die Vereinigten Staaten im Spiegel deutscher Informationsschriften für Auswanderer im 19. Jahrhundert

Elektronische Version der gedr. Ausg. 198

The Dark Side of the Sun A Critical Discourse Analysis of Ecological Modernisation in the Context of the Solar Economy in Morocco

This thesis is a critical investigation of the emerging solar economy in Morocco. The launch of the Moroccan Solar Plan in 2009 has attracted substantial amounts of foreign investment. Notably, several multilateral development banks support the country’s large-scale solar projects. Instead of climate change mitigation however, their engagement is rather framed by an eco-modern ideology that aims at the reconciliation of economic growth and environmental sustainability. Through a critical discourse analysis this thesis studies to what extent ecological modernisation discourse is present in four texts in which key stakeholders who represent European, German, African, and Moroccan interests justify their respective engagement in Morocco’s solar sector. By drawing on eco-modernisation discourse the actors present the sector as progressive and climate-friendly. The discourse is coupled with a hegemonic development discourse that equates growth and development. Both discourses are embedded in a complex web of neoliberal politics, unequal power relations and diverging group interests. The search for the topic of climate change in the texts revealed that it is dealt with in a vague manner that leaves open in what ways economic growth contributes to climate change mitigation

Unternehmensgründungen aus Hochschulen im regionalen Kontext: Gründungsneigung und Mobilitätsbereitschaft von Studierenden

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X-ray structure of the quinoprotein ethanol dehydrogenase from \u3ci\u3ePseudomonas aeruginosa\u3c/i\u3e: basis of substrate specificity

The homodimeric enzyme form of quinoprotein ethanol dehydrogenase from Pseudomonas aeruginosa ATCC 17933 crystallizes readily with the space group R3. The X-ray structure was solved at 2.6 Å resolution by molecular replacement. Aside from differences in some loops, the folding of the enzyme is very similar to the large subunit of the quinoprotein methanol dehydrogenases from Methylobacterium extorquens or Methylophilus W3A1. Eight W-shaped β-sheet motifs are arranged circularly in a propeller-like fashion forming a disk-shaped superbarrel. No electron density for a small subunit like that in methanol dehydrogenase could be found. The prosthetic group is located in the centre of the superbarrel and is coordinated to a calcium ion. Most amino acid residues found in close contact with the prosthetic group pyrroloquinoline quinone and the Ca2+ are conserved between the quinoprotein ethanol dehydrogenase structure and that of the methanol dehydrogenases. The main differences in the active-site region are a bulky tryptophan residue in the active-site cavity of methanol dehydrogenase, which is replaced by a phenylalanine and a leucine side-chain in the ethanol dehydrogenase structure and a leucine residue right above the pyrrolquinoline quinone group in methanol dehydrogenase which is replaced by a tryptophan side-chain. Both amino acid exchanges appear to have an important influence, causing different substrate specificities of these otherwise very similar enzymes. In addition to the Ca2+ in the active-site cavity found also in methanol dehydrogenase, ethanol dehydrogenase contains a second Ca2+-binding site at the N terminus, which contributes to the stability of the native enzyme

Probing Intranuclear Environments at the Single-Molecule Level

Genome activity and nuclear metabolism clearly depend on accessibility, but it is not known whether and to what extent nuclear structures limit the mobility and access of individual molecules. We used fluorescently labeled streptavidin with a nuclear localization signal as an average-sized, inert protein to probe the nuclear environment. The protein was injected into the cytoplasm of mouse cells, and single molecules were tracked in the nucleus with high-speed fluorescence microscopy. We analyzed and compared the mobility of single streptavidin molecules in structurally and functionally distinct nuclear compartments of living cells. Our results indicated that all nuclear subcompartments were easily and similarly accessible for such an average-sized protein, and even condensed heterochromatin neither excluded single molecules nor impeded their passage. The only significant difference was a higher frequency of transient trappings in heterochromatin, which lasted only tens of milliseconds. The streptavidin molecules, however, did not accumulate in heterochromatin, suggesting comparatively less free volume. Interestingly, the nucleolus seemed to exclude streptavidin, as it did many other nuclear proteins, when visualized by conventional fluorescence microscopy. The tracking of single molecules, nonetheless, showed no evidence for repulsion at the border but relatively unimpeded passage through the nucleolus. These results clearly show that single-molecule tracking can provide novel insights into mobility of proteins in the nucleus that cannot be obtained by conventional fluorescence microscopy. Our results suggest that nuclear processes may not be regulated at the level of physical accessibility but rather by local concentration of reactants and availability of binding sites