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Questions Has plant species richness in semi-natural grasslands changed over recent decades? Do the temporal trends of habitat specialists differ from those of habitat generalists? Has there been a homogenization of the grassland vegetation? Location Different regions in Germany and the UK. Methods We conducted a formal meta-analysis of re-survey vegetation studies of semi-natural grasslands. In total, 23 data sets were compiled, spanning up to 75 years between the surveys, including 13 data sets from wet grasslands, six from dry grasslands and four from other grassland types. Edaphic conditions were assessed using mean Ellenberg indicator values for soil moisture, nitrogen and pH. Changes in species richness and environmental variables were evaluated using response ratios. Results In most wet grasslands, total species richness declined over time, while habitat specialists almost completely vanished. The number of species losses increased with increasing time between the surveys and were associated with a strong decrease in soil moisture and higher soil nutrient contents. Wet grasslands in nature reserves showed no such changes or even opposite trends. In dry grasslands and other grassland types, total species richness did not consistently change, but the number or proportions of habitat specialists declined. There were also considerable changes in species composition, especially in wet grasslands that often have been converted into intensively managed, highly productive meadows or pastures. We did not find a general homogenization of the vegetation in any of the grassland types. Conclusions The results document the widespread deterioration of semi-natural grasslands, especially of those types that can easily be transformed to high production grasslands. The main causes for the loss of grassland specialists are changed management in combination with increased fertilization and nitrogen deposition. Dry grasslands are most resistant to change, but also show a long-term trend towards an increase in more mesotrophic species.
Agenda 21-Prozesse für zukunftsfähige Kommunen in Brandenburg KROHN, A.: Stadtentwicklung und Lokale Agenda 21 – Zwei Seiten einer Medaille ; MATERNE, S.: Agenda 21 in Oranienburg – die Entwicklung eines Leitbildes ; SCHLUTOW, A.; WILHELM, B.; METZDORF, R.; WILK, B., FÖRSTER, B.: Interessengemeinschaft "Ökologie 2000 - Unternehmer für die Umwelt" – Anstoß der Wirtschaft für eine lokale Agenda 21 in Strausberg ; SCHADE, B.: Agenda 21 im Landkreis Potsdam-Mittelmark – Rahmen für lokale Aktivitäten ; KITZIG, A.: Potsdam, Stadt der Toleranz – unterwegs mit Geschichts- und Verantwortungsbewußtsein für die Zukunft. Die Lokale Agenda 21 ; MÜLLER, J.: Umsetzung eines Klimaschutzkonzeptes – Schritte zu einer nachhaltigen Entwicklung der Stadt Eberswalde , HAASE, W.: Eine lokale Agenda 21 für Kleinmachnow , RÜCKERT-JOHN, J.: Auf dem Weg zur Nachhaltigkeit. Ergebnisse einer Dorfstudie
Portal alumni
(2013)
Begonnen hat es um 1900 mit Qualitätskontrolle, später folgte Qualitätsprüfung und seit Mitte der 90er Jahre hat das Thema Qualitätsmanagement Einzug gehalten in alle Bereiche von Politik und Gesellschaft. Im Gesundheitswesen, der Justiz und auch an vielen Hochschulen wurden spezielle Stellen eingerichtet, die sich gezielt mit der Umsetzung von Qualitätsentwicklung oder Qualitätsmanagement befassen. Das übergeordnete Ziel bei Einführung eines Qualitätsmanagements ist es, die Wettbewerbsfähigkeit der Organisation sowie auch die Zufriedenheit der Mitglieder der Institutionen und weiterer Stakeholder zu steigern, indem die Qualität der Tätigkeiten und der jeweiligen Rahmenbedingungen erhalten und optimiert wird. Mit der bewussten Entscheidung zur Qualitätssicherung und -entwicklung beginnt ein fortlaufender Prozess, der stetig intensiv begleitet werden muss. Qualitätsmanagement wirkt nachhaltig, in dem durch die Schaffung regelmäßiger und systematischer Strukturen und Prozesse auch zukünftig den beteiligten Personen ein optimales Handeln entsprechend der dann geltenden Bedingungen ermöglicht wird. Portal alumni widmet sich in seinem zehnten Heft diesem Thema und hat Absolventen der Universität Potsdam nach ihrem Tätigkeitsfeld im Qualitätsmanagement und den entsprechenden Erfolgen befragt. Dabei zeigt sich, dass Ehemalige Einsatzbereiche in Wirtschaft und Unternehmen aber auch in Sport, Bildung oder Hochschulen gefunden haben. Daneben berichten wir in diesem Heft von einem Projekt des Career Service, dem Schnupperjobben, und auch die Berichte über die Geschehnisse an Ihrer Alma mater kommen nicht zu kurz.
Hydrogel systems based on hydroxyethyl starch-polyethylene glycol methacrylate (HES-P(EG)(6)MA) or hydroxyethyl starch methacrylate (HES-MA) were used to assess the protein release behavior. Here, we analyzed the in vitro release of FITC-anti-human antibodies incorporated in either HES-P(EG)(6)MA or HES-MA hydrogel delivery systems in PBS or human serum. In addition, hydrogel disks and microparticles prepared from the two polymers were subcutaneously implanted in BALB/c mice. The in vivo release of FITC-IgG was non-invasively monitored by an in vivo imaging system (IVIS 200) over a time period of up to 3 months. The imaging system allowed to asses individual animals over time, therefore only a small number of animals was required to obtain high quality data. The reduction in fluorescence intensity at the site of administration was compared to in vitro release profiles. These investigations demonstrated a sustained release from HES-MA hydrogel disks compared to rapidly degrading HES-P(EG)(6)MA disks and microparticles. The sustained release from HES-MA disks could be further optimized by using increased polymer concentrations. Human serum as in vitro release medium reflected better the in vivo release from HES-P(EG)(6)MA systems than PBS, suggesting that the presence of organic substances like proteins or lipids may play a significant role for the release kinetics.
Bacteriophage HK620 infects Escherichia coli H and is closely related to Shigella phage Sf6 and Salmonella phage P22. All three Podoviridae recognize and cleave their respective host cell receptor polysaccharide by homotrimeric tailspike proteins. The three proteins exhibit high sequence identity in the 110 residues of their N-terminal particle- binding domains, but no apparent sequence similarity in their major, receptor-binding parts. We have biochemically characterized the receptor-binding part of HK620 tailspike and determined its crystal structure to 1.38 Å resolution. Its major domain is a right-handed parallel ;-helix, as in Sf6 and P22 tailspikes. HK620 tailspike has endo-N- acetylglucosaminidase activity and produces hexasaccharides of an O18A1-type O-antigen. As indicated by the structure of a hexasaccharide complex determined at 1.6 Å resolution, the endoglycosidase-active sites are located intramolecularly, as in P22, and not between subunits, as in Sf6 tailspike. In contrast, the extreme C-terminal domain of HK620 tailspike forms a ;-sandwich, as in Sf6 and unlike P22 tailspike. Despite the different folds, structure-based sequence alignments of the C-termini reveal motifs conserved between the three proteins. We propose that the tailspike genes of P22, Sf6 and HK620 have a common precursor and are not mosaics of unrelated gene fragments.
Sf6 belongs to the Podoviridae family of temperate bacteriophages that infect gram-negative bacteria by insertion of their double-stranded DNA. They attach to their hosts specifically via their tailspike proteins. The 1.25 Å crystal structure of Shigella phage Sf6 tailspike protein (Sf6 TSP) reveals a conserved architecture with a central, right-handed ; helix. In the trimer of Sf6 TSP, the parallel ; helices form a left-handed, coiled;; coil with a pitch of 340 Å. The C-terminal domain consists of a ; sandwich reminiscent of viral capsid proteins. Further crystallographic and biochemical analyses show a Shigella cell wall O-antigen fragment to bind to an endorhamnosidase active site located between two ;-helix subunits each anchoring one catalytic carboxylate. The functionally and structurally related bacteriophage, P22 TSP, lacks sequence identity with Sf6 TSP and has its active sites on single subunits. Sf6 TSP may serve as an example for the evolution of different host specificities on a similar general architecture.
Bacteriophage HK620 recognizes and cleaves the O-antigen polysaccharide of Escherichia coli serogroup O18A1 with its tailspike protein (TSP). HK620TSP binds hexasaccharide fragments with low affinity, but single amino acid exchanges generated a set of high-affinity mutants with submicromolar dissociation constants. Isothermal titration calorimetry showed that only small amounts of heat were released upon complex formation via a large number of direct and solvent-mediated hydrogen bonds between carbohydrate and protein. At room temperature, association was both enthalpy- and entropy-driven emphasizing major solvent rearrangements upon complex formation. Crystal structure analysis showed identical protein and sugar conformers in the TSP complexes regardless of their hexasaccharide affinity. Only in one case, a TSP mutant bound a different hexasaccharide conformer. The extended sugar binding site could be dissected in two regions: first, a hydrophobic pocket at the reducing end with minor affinity contributions. Access to this site could be blocked by a single aspartate to asparagine exchange without major loss in hexasaccharide affinity. Second, a region where the specific exchange of glutamate for glutamine created a site for an additional water molecule. Side-chain rearrangements upon sugar binding led to desolvation and additional hydrogen bonding which define this region of the binding site as the high-affinity scaffold.
Grenzen sind immanenter Bestandteil der internationalen Beziehungen. Deren Kern besteht ja darin, dass Akteure über (nationalstaatliche) Grenzen hinweg handeln. Die Grenze und deren Überschreitung sind somit eine conditio sine qua non von internationalen Beziehungen. Das stellt sich in Europa, Amerika und Afrika sehr verschieden dar und wird auch unterschiedlich diskutiert. Der vorliegende Band bildet dies ab: die theoretische Debatte und die empirische Verschiedenheit in den Regionen, wobei die Europäische Union den regionalen Schwerpunkt bildet. Der vorliegende Band, der auf einen Lehrtext von 2005 aufbaut, enthält neue Texte zu Amerika und zu Europas Ostgrenze.
Herein, we report the synthesis of two phenylaza-[18]crown-6 lariat ethers with a coumarin fluorophore (1 and 2) and we reveal that compound 1 is an excellent probe for K+ ions under simulated physiological conditions. The presence of a 2-methoxyethoxy lariat group at the ortho position of the anilino moiety is crucial to the substantially increased stability of compounds 1 and 2 over their lariat-free phenylaza-[18] crown-6 ether analogues. Probe 1 shows a high K+/Na+ selectivity and a 2.5-fold fluorescence enhancement was observed in the presence of 100 mm K+ ions. A fluorescent membrane sensor, which was prepared by incorporating probe 1 into a hydrogel, showed a fully reversible response, a response time of 150 s, and a signal change of 7.8% per 1 mm K+ within the range 1-10 mm K+. The membrane was easily fabricated (only a single sensing layer on a solid polyester support), yet no leaching was observed. Moreover, compound 1 rapidly permeated into cells, was cytocompatible, and was suitable for the fluorescent imaging of K+ ions on both the extracellular and intracellular levels.