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Die taxonomische Umgrenzung und interpretation von Hieracium fallax war im 19. Jahrhundert sehr unklar und teilweise schwankend. Sie hat dann vor allem durch die Monographie von Nägeli & Peter (1889) eine starke Wandlung erfahren, die mit Beschreibung bei Willdenow (1809) und dem Typus-Material in B nicht mehr übereinstimmt. Die Geschichte dieses Bedeutungswandels wird kurz dargelegt. Der von Bräutigam & Greuter (2007) im Zuge der Ausgliederung von Pilosella aus Hieracium vorgenommene Namenswechsel zu P. setigera Fr. ist zu korrigieren, da für die betreffende „echioides-cymosum“- Zwischenart mit H. cymosiforme Froel. ein älterer Name aufgegriffen werden muss. Die Namen H. cymosiforme, H. fallax und Pilosella setigera werden lectotypisiert und die Neukombination P. cymosiformis vorgenommen.
Acinetobacter baumannii is a nosocomial pathogen which can persist in the hospital environment not only due to the acquirement of multiple antibiotic resistances, but also because of its exceptional resistance against disinfectants and desiccation. A suitable desiccation assay was established in which A. baumannii ATCC 19606T survived for ca. 1 month. The growth medium slightly influenced survival after subsequent desiccation. A significant effect could be attributed to the growth phase in which bacteria were dried: In exponential phase, cells were much more desiccation sensitive. The main focus of the present study was the elucidation of the role of compatible solutes, which are known to protect many bacteria under low water activity conditions, in desiccation survival of A. baumannii. Exogenous trehalose was shown to efficiently protect A. baumannii on dry surfaces, in contrast to other compatible solutes tested such as mannitol or glycine betaine. To analyze the importance of intracellularly accumulated solutes, a double mutant lacking biosynthesis pathways for mannitol and trehalose was generated. This mutant accumulated glutamate as sole solute in the presence of high NaCl concentrations and showed severe growth defects under osmotic stress conditions. However, no effect on desiccation tolerance could be seen, neither when cells were dried in water nor in the presence of NaCl.
The centrosome linker proteins C-Nap1, rootletin, and CEP68 connect the two centrosomes of a cell during interphase into one microtubule-organizing center. This coupling is important for cell migration, cilia formation, and timing of mitotic spindle formation. Very little is known about the structure of the centrosome linker. Here, we used stimulated emission depletion (STED) microscopy to show that each C-Nap1 ring at the proximal end of the two centrioles organizes a rootletin ring and, in addition, multiple rootletin/CEP68 fibers. Rootletin/CEP68 fibers originating from the two centrosomes form a web-like, interdigitating network, explaining the flexible nature of the centrosome linker. The rootletin/CEP68 filaments are repetitive and highly ordered. Staggered rootletin molecules (N-to-N and C-to-C) within the filaments are 75 nm apart. Rootletin binds CEP68 via its C-terminal spectrin repeat-containing region in 75-nm intervals. The N-to-C distance of two rootletin molecules is ∼35 to 40 nm, leading to an estimated minimal rootletin length of ∼110 nm. CEP68 is important in forming rootletin filaments that branch off centrioles and to modulate the thickness of rootletin fibers. Thus, the centrosome linker consists of a vast network of repeating rootletin units with C-Nap1 as ring organizer and CEP68 as filament modulator.
Complex I (proton-pumping NADH:ubiquinone oxidoreductase) is the largest enzyme of the mitochondrial respiratory chain and a significant source of reactive oxygen species (ROS). We hypothesized that during energy conversion by complex I, electron transfer onto ubiquinone triggers the concerted rearrangement of three protein loops of subunits ND1, ND3, and 49-kDa thereby generating the power-stoke driving proton pumping. Here we show that fixing loop TMH1-2ND3 to the nearby subunit PSST via a disulfide bridge introduced by site-directed mutagenesis reversibly disengages proton pumping without impairing ubiquinone reduction, inhibitor binding or the Active/Deactive transition. The X-ray structure of mutant complex I indicates that the disulfide bridge immobilizes but does not displace the tip of loop TMH1-2ND3. We conclude that movement of loop TMH1-2ND3 located at the ubiquinone-binding pocket is required to drive proton pumping corroborating one of the central predictions of our model for the mechanism of energy conversion by complex I proposed earlier.
Light absorption of myoglobin triggers diatomic ligand photolysis and a spin crossover transition of iron(II) that initiate protein conformational change. The photolysis and spin crossover reactions happen concurrently on a femtosecond timescale. The microscopic origin of these reactions remains controversial. Here, we apply quantum wavepacket dynamics to elucidate the ultrafast photochemical mechanism for a heme–carbon monoxide (heme–CO) complex. We observe coherent oscillations of the Fe–CO bond distance with a period of 42 fs and an amplitude of ∼1 Å. These nuclear motions induce pronounced geometric reorganization, which makes the CO dissociation irreversible. The reaction is initially dominated by symmetry breaking vibrations inducing an electron transfer from porphyrin to iron. Subsequently, the wavepacket relaxes to the triplet manifold in ∼75 fs and to the quintet manifold in ∼430 fs. Our results highlight the central role of nuclear vibrations at the origin of the ultrafast photodynamics of organometallic complexes.
Previous magnetoencephalography (MEG) studies have revealed gamma-band activity at sensors over parietal and fronto-temporal cortex during the delay phase of auditory spatial and non-spatial match-to-sample tasks, respectively. While this activity was interpreted as reflecting the memory maintenance of sound features, we noted that task-related activation differences might have been present already prior to the onset of the sample stimulus. The present study focused on the interval between a visual cue indicating which sound feature was to be memorized (lateralization or pitch) and sample sound presentation to test for task-related activation differences preceding stimulus encoding. MEG spectral activity was analyzed with cluster randomization tests (N = 15). Whereas there were no differences in frequencies below 40 Hz, gamma-band spectral amplitude (about 50–65 and 90–100 Hz) was higher for the lateralization than the pitch task. This activity was localized at right posterior and central sensors and present for several hundred ms after task cue offset. Activity at 50–65 Hz was also increased throughout the delay phase for the lateralization compared with the pitch task. Apparently cortical networks related to auditory spatial processing were activated after participants had been informed about the task.
The ATP-binding cassette transporter TAPL translocates polypeptides from the cytosol into the lysosomal lumen. TAPL can be divided into two functional units: coreTAPL, active in ATP-dependent peptide translocation, and the N-terminal membrane spanning domain, TMD0, responsible for cellular localization and interaction with the lysosomal associated membrane proteins LAMP-1 and LAMP-2. Although the structure and function of ABC transporters were intensively analyzed in the past, the knowledge about accessory membrane embedded domains is limited. Therefore, we expressed the TMD0 of TAPL via a cell-free expression system and confirmed its correct folding by NMR and interaction studies. In cell as well as cell-free expressed TMD0 forms oligomers, which were assigned as dimers by PELDOR spectroscopy and static light scattering. By NMR spectroscopy of uniformly and selectively isotope labeled TMD0 we performed a complete backbone and partial side chain assignment. Accordingly, TMD0 has a four transmembrane helix topology with a short helical segment in a lysosomal loop. The topology of TMD0 was confirmed by paramagnetic relaxation enhancement with paramagnetic stearic acid as well as by nuclear Overhauser effects with c6-DHPC and cross-peaks with water.
Some students evidently find it difficult to paraphrase the content of a text (particularly a specialist or professional text) after reading it. This inability may have a negative impact on their performance when writing Bachelor theses or when studying in general. This paper therefore addresses the question of how to help students of German develop the important competency of paraphrasing and summarizing the content of texts. The starting point was a small-scale research project conducted among students at the Department of German Studies, Faculty of Arts, University of Ostrava; the results of the research were analyzed to identify the main problems encountered by students when carrying out these tasks. This analysis forms the basis for an overview of strategies and methods which can be practised by students when paraphrasing and summarizing the content of texts. The article systematizes the key processes and operations for paraphrasing and summarizing with reference to the theoretical literature. The article seeks to contribute to the discussion of a broad range of methods that can be used to help improve the quality of foreign language studies and the study of specialist and professional language
The recent recolonisation of the Central European lowland (CEL) by the grey wolf (Canis lupus) provides an excellent opportunity to study the effect of founder events on endoparasite diversity. Which role do prey and predator populations play in the re-establishment of endoparasite life cycles? Which intrinsic and extrinsic factors control individual endoparasite diversity in an expanding host population? In 53 individually known CEL wolves sampled in Germany, we revealed a community of four cestode, eight nematode, one trematode and 12 potential Sarcocystis species through molecular genetic techniques. Infections with zoonotic Echinococcus multilocularis, Trichinella britovi and T. spiralis occurred as single cases. Per capita endoparasite species richness and diversity significantly increased with population size and changed with age, whereas sex, microsatellite heterozygosity, and geographic origin had no effect. Tapeworm abundance (Taenia spp.) was significantly higher in immigrants than natives. Metacestode prevalence was slightly higher in ungulates from wolf territories than from control areas elsewhere. Even though alternative canid definitive hosts might also play a role within the investigated parasite life cycles, our findings indicate that (1) immigrated wolves increase parasite diversity in German packs, and (2) prevalence of wolf-associated parasites had declined during wolf absence and has now risen during recolonisation.