TY - JOUR A1 - Chen, Yi-chun A1 - Mishra, Dushyant A1 - Gläß, Sebastian A1 - Gerber, Bertram T1 - Behavioral Evidence for Enhanced Processing of the Minor Component of Binary Odor Mixtures in Larval Drosophila JF - Frontiers in Psychology N2 - A fundamental problem in deciding between mutually exclusive options is that the decision needs to be categorical although the properties of the options often differ but in grade. We developed an experimental handle to study this aspect of behavior organization. Larval Drosophila were trained such that in one set of animals odor A was rewarded, but odor B was not (A+/B), whereas a second set of animals was trained reciprocally (A/B+). We then measured the preference of the larvae either for A, or for B, or for “morphed” mixtures of A and B, that is for mixtures differing in the ratio of the two components. As expected, the larvae showed higher preference when only the previously rewarded odor was presented than when only the previously unrewarded odor was presented. For mixtures of A and B that differed in the ratio of the two components, the major component dominated preference behavior—but it dominated less than expected from a linear relationship between mixture ratio and preference behavior. This suggests that a minor component can have an enhanced impact in a mixture, relative to such a linear expectation. The current paradigm may prove useful in understanding how nervous systems generate discrete outputs in the face of inputs that differ only gradually. KW - learning KW - memory KW - perception KW - compound conditioning KW - decision-making KW - Drosophila Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170011 VL - 8 IS - 1923 ER - TY - JOUR A1 - Cheng, Cheng A1 - Othman, Eman M. A1 - Stopper, Helga A1 - Edrada-Ebel, RuAngelie A1 - Hentschel, Ute A1 - Abdelmohsen, Usama Ramadan T1 - Isolation of petrocidin A, a new cytotoxic cyclic dipeptide from the marine sponge-derived bacterium \(Streptomyces\) sp. SBT348 JF - Marine Drugs N2 - A new cyclic dipeptide, petrocidin A (\(\textbf{1}\)), along with three known compounds—2,3-dihydroxybenzoic acid (\(\textbf{2}\)), 2,3-dihydroxybenzamide (\(\textbf{3}\)), and maltol (\(\textbf{4}\))—were isolated from the solid culture of \(Streptomyces\) sp. SBT348. The strain \(Streptomyces\) sp. SBT348 had been prioritized in a strain collection of 64 sponge-associated actinomycetes based on its distinct metabolomic profile using liquid chromatography/high-resolution mass spectrometry (LC-HRMS) and nuclear magnetic resonance (NMR). The absolute configuration of all α-amino acids was determined by HPLC analysis after derivatization with Marfey’s reagent and comparison with commercially available reference amino acids. Structure elucidation was pursued in the presented study by mass spectrometry and NMR spectral data. Petrocidin A (\(\textbf{1}\)) and 2,3-dihydroxybenzamide (\(\textbf{3}\)) exhibited significant cytotoxicity towards the human promyelocytic HL-60 and the human colon adenocarcinoma HT-29 cell lines. These results demonstrated the potential of sponge-associated actinomycetes for the discovery of novel and pharmacologically active natural products. KW - biology KW - sponges KW - actinomycetes KW - streptomyces KW - cyclic dipeptide KW - cytotoxic Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-172644 VL - 15 IS - 12 ER - TY - JOUR A1 - Chiesa, Mauro A1 - Greiner, Nicolas A1 - Schönherr, Marek A1 - Tramontano, Francesco T1 - Electroweak corrections to diphoton plus jets JF - Journal of High Energy Physics N2 - We calculate the next-to-leading order electroweak corrections to the production of a photon pair in association with zero, one and two jets at the LHC. We use GoSam and Sherpa to obtain the results in a fully automated way. For a typical set of fiducial cuts the electroweak corrections lead to a modification of the total cross section of up to 3%, depending on the jet multiplicity. We find substantial contributions in differential distributions, leading to tens of per cent corrections for phase space regions within the reach of the LHC. Furthermore we investigate the importance of photon induced processes as well as subleading contributions. Photon induced processes are found to be negligible, subleading contributions can have a sizeable impact however they can be removed by appropriate phase space cuts. KW - NLO computations Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-173512 IS - 10 ER - TY - JOUR A1 - Collenburg, Lena A1 - Beyersdorf, Niklas A1 - Wiese, Teresa A1 - Arenz, Christoph A1 - Saied, Essa M. A1 - Becker-Flegler, Katrin Anne A1 - Schneider-Schaulies, Sibylle A1 - Avota, Elita T1 - The activity of the neutral sphingomyelinase is important in T cell recruitment and directional migration JF - Frontiers in Immunology N2 - Breakdown of sphingomyelin as catalyzed by the activity of sphingomyelinases profoundly affects biophysical properties of cellular membranes which is particularly important with regard to compartmentalization of surface receptors and their signaling relay. As it is activated both upon TCR ligation and co-stimulation in a spatiotemporally controlled manner, the neutral sphingomyelinase (NSM) has proven to be important in T cell activation, where it appears to play a particularly important role in cytoskeletal reorganization and cell polarization. Because these are important parameters in directional T cell migration and motility in tissues, we analyzed the role of the NSM in these processes. Pharmacological inhibition of NSM interfered with early lymph node homing of T cells in vivo indicating that the enzyme impacts on endothelial adhesion, transendothelial migration, sensing of chemokine gradients or, at a cellular level, acquisition of a polarized phenotype. NSM inhibition reduced adhesion of T cells to TNF-α/IFN-γ activated, but not resting endothelial cells, most likely via inhibiting high-affinity LFA-1 clustering. NSM activity proved to be highly important in directional T cell motility in response to SDF1-α, indicating that their ability to sense and translate chemokine gradients might be NSM dependent. In fact, pharmacological or genetic NSM ablation interfered with T cell polarization both at an overall morphological level and redistribution of CXCR4 and pERM proteins on endothelial cells or fibronectin, as well as with F-actin polymerization in response to SDF1-α stimulation, indicating that efficient directional perception and signaling relay depend on NSM activity. Altogether, these data support a central role of the NSM in T cell recruitment and migration both under homeostatic and inflamed conditions by regulating polarized redistribution of receptors and their coupling to the cytoskeleton. KW - LFA-1 KW - neutral sphingomyelinase KW - T cell migration KW - ceramide KW - polarization KW - adhesion Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-158944 VL - 8 IS - 1007 ER - TY - JOUR A1 - Costea, Paul I. A1 - Coelho, Louis Pedro A1 - Sunagawa, Shinichi A1 - Munch, Robin A1 - Huerta-Cepas, Jaime A1 - Forslund, Kristoffer A1 - Hildebrand, Falk A1 - Kushugulova, Almagul A1 - Zeller, Georg A1 - Bork, Peer T1 - Subspecies in the global human gut microbiome JF - Molecular Systems Biology N2 - Population genomics of prokaryotes has been studied in depth in only a small number of primarily pathogenic bacteria, as genome sequences of isolates of diverse origin are lacking for most species. Here, we conducted a large‐scale survey of population structure in prevalent human gut microbial species, sampled from their natural environment, with a culture‐independent metagenomic approach. We examined the variation landscape of 71 species in 2,144 human fecal metagenomes and found that in 44 of these, accounting for 72% of the total assigned microbial abundance, single‐nucleotide variation clearly indicates the existence of sub‐populations (here termed subspecies). A single subspecies (per species) usually dominates within each host, as expected from ecological theory. At the global scale, geographic distributions of subspecies differ between phyla, with Firmicutes subspecies being significantly more geographically restricted. To investigate the functional significance of the delineated subspecies, we identified genes that consistently distinguish them in a manner that is independent of reference genomes. We further associated these subspecies‐specific genes with properties of the microbial community and the host. For example, two of the three Eubacterium rectale subspecies consistently harbor an accessory pro‐inflammatory flagellum operon that is associated with lower gut community diversity, higher host BMI, and higher blood fasting insulin levels. Using an additional 676 human oral samples, we further demonstrate the existence of niche specialized subspecies in the different parts of the oral cavity. Taken together, we provide evidence for subspecies in the majority of abundant gut prokaryotes, leading to a better functional and ecological understanding of the human gut microbiome in conjunction with its host. KW - biology KW - genetic variation KW - metagenomics KW - microbiome KW - population structure KW - prokaryotic subspecies Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-172674 VL - 13 IS - 12 ER - TY - JOUR A1 - Dainese, Matteo A1 - Schneider, Gudrun A1 - Krauss, Jochen A1 - Steffan-Dewenter, Ingolf T1 - Complementarity among natural enemies enhances pest suppression JF - Scientific Reports N2 - Natural enemies have been shown to be effective agents for controlling insect pests in crops. However, it remains unclear how different natural enemy guilds contribute to the regulation of pests and how this might be modulated by landscape context. In a field exclusion experiment in oilseed rape (OSR), we found that parasitoids and ground-dwelling predators acted in a complementary way to suppress pollen beetles, suggesting that pest control by multiple enemies attacking a pest during different periods of its occurrence in the field improves biological control efficacy. The density of pollen beetle significantly decreased with an increased proportion of non-crop habitats in the landscape. Parasitism had a strong effect on pollen beetle numbers in landscapes with a low or intermediate proportion of non-crop habitats, but not in complex landscapes. Our results underline the importance of different natural enemy guilds to pest regulation in crops, and demonstrate how biological control can be strengthened by complementarity among natural enemies. The optimization of natural pest control by adoption of specific management practices at local and landscape scales, such as establishing non-crop areas, low-impact tillage, and temporal crop rotation, could significantly reduce dependence on pesticides and foster yield stability through ecological intensification in agriculture. KW - ecosystem services KW - agroecology Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-158621 VL - 7 ER - TY - JOUR A1 - Danner, Nadja A1 - Keller, Alexander A1 - Härtel, Stephan A1 - Steffan-Dewenter, Ingolf T1 - Honey bee foraging ecology: Season but not landscape diversity shapes the amount and diversity of collected pollen JF - PLoS ONE N2 - The availability of pollen in agricultural landscapes is essential for the successful growth and reproduction of honey bee colonies (Apis mellifera L.). The quantity and diversity of collected pollen can influence the growth and health of honey bee colonies, but little is known about the influence of landscape structure on pollen diet. In a field experiment, we rotated 16 honey bee colonies across 16 agricultural landscapes, used traps to collect samples of collected pollen and observed intra-colonial dance communication to gain information about foraging distances. DNA metabarcoding was applied to analyze mixed pollen samples. Neither the amount of collected pollen nor pollen diversity was related to landscape diversity. However, we found a strong seasonal variation in the amount and diversity of collected pollen in all sites independent of landscape diversity. The observed increase in foraging distances with decreasing landscape diversity suggests that honey bees compensated for lower landscape diversity by increasing their pollen foraging range in order to maintain pollen amount and diversity. Our results underscore the importance of a diverse pollen diet for honey bee colonies. Agri-environmental schemes aiming to support pollinators should focus on possible spatial and temporal gaps in pollen availability and diversity in agricultural landscapes. KW - honey bees KW - pollen KW - season KW - foraging Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170424 VL - 12 IS - 8 ER - TY - JOUR A1 - Deacon, R. S. A1 - Wiedenmann, J. A1 - Bocquillon, E. A1 - Domínguez, F. A1 - Klapwijk, T. M. A1 - Leubner, P. A1 - Brüne, C. A1 - Hankiewicz, E. M. A1 - Tarucha, S. A1 - Ishibashi, K. A1 - Buhmann, H. A1 - Molenkamp, L. W. T1 - Josephson Radiation from Gapless Andreev Bound States in HgTe-Based Topological Junctions JF - Physical Review X N2 - Frequency analysis of the rf emission of oscillating Josephson supercurrent is a powerful passive way of probing properties of topological Josephson junctions. In particular, measurements of the Josephson emission enable the detection of topological gapless Andreev bound states that give rise to emission at half the Josephson frequency f\(_{J}\) rather than conventional emission at f\(_{J}\). Here, we report direct measurement of rf emission spectra on Josephson junctions made of HgTe-based gate-tunable topological weak links. The emission spectra exhibit a clear signal at half the Josephson frequency f\(_{J}\)/2. The linewidths of emission lines indicate a coherence time of 0.3–4 ns for the f\(_{J}\)/2 line, much shorter than for the f\(_{J}\) line (3–4 ns). These observations strongly point towards the presence of topological gapless Andreev bound states and pave the way for a future HgTe-based platform for topological quantum computation. KW - condensed matter physics KW - Josephson junctions KW - topological materials KW - gapless Andreev bound states Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170969 VL - 7 IS - 021011 ER - TY - JOUR A1 - Degen, Tobias A1 - Hovestadt, Thomas A1 - Mitesser, Oliver A1 - Hölker, Franz T1 - Altered sex-specific mortality and female mating success: ecological effects and evolutionary responses JF - Ecosphere N2 - Theory predicts that males and females should often join the mating pool at different times (sexual dimorphism in timing of emergence [SDT]) as the degree of SDT affects female mating success. We utilize an analytical model to explore (1) how important SDT is for female mating success, (2) how mating success might change if either sex's mortality (abruptly) increases, and (3) to what degree evolutionary responses in SDT may be able to mitigate the consequences of such mortality increase. Increasing male pre‐mating mortality has a non‐linear effect on the fraction of females mated: The effect is initially weak, but at some critical level a further increase in male mortality has a stronger effect than a similar increase in female mortality. Such a change is expected to impose selection for reduced SDT. Increasing mortality during the mating season has always a stronger effect on female mating success if the mortality affects the sex that emerges first. This bias results from the fact that enhancing mortality of the earlier emerging sex reduces female–male encounter rates. However, an evolutionary response in SDT may effectively mitigate such consequences. Further, if considered independently for females and males, the predicted evolutionary response in SDT could be quite dissimilar. The difference between female and male evolutionary response in SDT leads to marked differences in the fraction of fertilized females under certain conditions. Our model may provide general guidelines for improving harvesting of populations, conservation management of rare species under altered environmental conditions, or maintaining long‐term efficiency of pest‐control measures. KW - evolutionary response KW - sexual dimorphism in timing KW - sex-specific mortality KW - reproductive asynchrony KW - mating success Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170953 VL - 8 IS - 5 ER - TY - JOUR A1 - Denner, Ansgar A1 - Lang, Jean-Nicolas A1 - Pellen, Mathieu A1 - Uccirati, Sandro T1 - Higgs production in association with off-shell top-antitop pairs at NLO EW and QCD at the LHC JF - Journal of High Energy Physics N2 - We present NLO electroweak corrections to Higgs production in association with off-shell top-antitop quark pairs. The full process pp → e +νeµ −ν¯µbb¯H is considered, and hence all interference, off-shell, and non-resonant contributions are taken into account. The electroweak corrections turn out to be below one per cent for the integrated cross section but can exceed 10% in certain phase-space regions. In addition to its phenomenological relevance, the computation constitutes a major technical achievement as the full NLO virtual corrections involving up to 9-point functions have been computed exactly. The results of the full computation are supported by two calculations in the double-pole approximation. These also allow to infer the effect of off-shell contributions and emphasise their importance especially for the run II of the LHC. Finally, we present combined predictions featuring both NLO electroweak and QCD corrections in a common set-up that will help the experimental collaborations in their quest of precisely measuring the aforementioned process. KW - high energy physics KW - NLO computations Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-171871 IS - 2 ER - TY - JOUR A1 - Denner, Ansgar A1 - Lang, Jean-Nicolas A1 - Uccirati, Sandro T1 - NLO electroweak corrections in extended Higgs sectors with RECOLA2 JF - Journal of High Energy Physics N2 - We present the computer code RECOLA2 along with the first NLO electroweak corrections to Higgs production in vector-boson fusion and updated results for Higgs strahlung in the Two-Higgs-Doublet Model and Higgs-Singlet extension of the Standard Model. A fully automated procedure for the generation of tree-level and one-loop matrix elements in general models, including renormalization, is presented. We discuss the application of the Background-Field Method to the extended models. Numerical results for NLO electroweak cross sections are presented for different renormalization schemes in the Two-Higgs-Doublet Model and the Higgs-Singlet extension of the Standard Model. Finally, we present distributions for the production of a heavy Higgs boson. KW - NLO computations KW - phenomenological models KW - Higgs boson Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170673 VL - 7 IS - 87 ER - TY - JOUR A1 - Dick, Julia A1 - Krauß, Patrizia A1 - Hillenkamp, Jost A1 - Kohlmorgen, Britta A1 - Schoen, Christoph T1 - Postoperative Tropheryma whipplei endophthalmitis – a case report highlighting the additive value of molecular testing JF - JMM Case Reports N2 - Introduction. Tropheryma whipplei is the causative agent of Whipple’s disease. Gastrointestinal and lymphatic tissues are affected in the majority of cases, resulting in diarrhoea, malabsorption and fever. Here, we report a rare case of ocular manifestation in a patient lacking the typical Whipple symptoms. Case presentation. A 74-year-old Caucasian female presented with blurred vision in the right eye over a period of 1–2 months, accompanied by stinging pain and conjunctival hyperaemia for the last 2 days. Upon admission, visual acuity was hand motion in the affected eye. Ophthalmological examination showed typical signs of intraocular inflammation. Diagnostic and therapeutic pars plana vitrectomy including vitreous biopsy and intravitreal instillation of vancomycin and amikacin was performed within hours of initial presentation. Both microscopic analysis and microbial cultures of the vitreous biopsy remained negative for bacteria and fungi. The postoperative antibiotic regime included intravenous administration of ceftriaxone in combination with topical tobramycin and ofloxacin. Due to the empirical therapy the inflammation ceased and the patient was discharged after 5 days with cefpodoxime orally and local antibiotic and steroidal therapy. Meanwhile, the vitreous body had undergone testing by PCR for the eubacterial 16S rRNA gene, which was found to be positive. Analysis of the PCR product revealed a specific sequence of T. whipplei. Conclusion. In our patient, endophthalmitis was the first and only symptom of Morbus Whipple, while most patients with Whipple’s disease suffer from severe gastrointestinal symptoms. 16S rDNA PCR should be considered for any intraocular infection when microscopy and standard culture methods remain negative. KW - intravitreal vancomycin and amikacin KW - intravenous ceftriaxone KW - topic ofloxacin KW - Whipple's disease KW - endophthalmitis KW - Tropheryma whipplei KW - ocular infection KW - vitrectomy KW - oral cefpodoxime KW - oral doxycycline Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-158823 VL - 4 ER - TY - JOUR A1 - Dombert, Benjamin A1 - Balk, Stefanie A1 - Lüningschrör, Patrick A1 - Moradi, Mehri A1 - Sivadasan, Rajeeve A1 - Saal-Bauernschubert, Lena A1 - Jablonka, Sibylle T1 - BDNF/trkB induction of calcium transients through Ca\(_{v}\)2.2 calcium channels in motoneurons corresponds to F-actin assembly and growth cone formation on β2-chain laminin (221) JF - Frontiers in Molecular Neuroscience N2 - Spontaneous Ca\(^{2+}\) transients and actin dynamics in primary motoneurons correspond to cellular differentiation such as axon elongation and growth cone formation. Brain-derived neurotrophic factor (BDNF) and its receptor trkB support both motoneuron survival and synaptic differentiation. However, in motoneurons effects of BDNF/trkB signaling on spontaneous Ca\(^{2+}\) influx and actin dynamics at axonal growth cones are not fully unraveled. In our study we addressed the question how neurotrophic factor signaling corresponds to cell autonomous excitability and growth cone formation. Primary motoneurons from mouse embryos were cultured on the synapse specific, β2-chain containing laminin isoform (221) regulating axon elongation through spontaneous Ca\(^{2+}\) transients that are in turn induced by enhanced clustering of N-type specific voltage-gated Ca\(^{2+}\) channels (Ca\(_{v}\)2.2) in axonal growth cones. TrkB-deficient (trkBTK\(^{-/-}\)) mouse motoneurons which express no full-length trkB receptor and wildtype motoneurons cultured without BDNF exhibited reduced spontaneous Ca\(^{2+}\) transients that corresponded to altered axon elongation and defects in growth cone morphology which was accompanied by changes in the local actin cytoskeleton. Vice versa, the acute application of BDNF resulted in the induction of spontaneous Ca\(^{2+}\) transients and Ca\(_{v}\)2.2 clustering in motor growth cones, as well as the activation of trkB downstream signaling cascades which promoted the stabilization of β-actin via the LIM kinase pathway and phosphorylation of profilin at Tyr129. Finally, we identified a mutual regulation of neuronal excitability and actin dynamics in axonal growth cones of embryonic motoneurons cultured on laminin-221/211. Impaired excitability resulted in dysregulated axon extension and local actin cytoskeleton, whereas upon β-actin knockdown Ca\(_{v}\)2.2 clustering was affected. We conclude from our data that in embryonic motoneurons BDNF/trkB signaling contributes to axon elongation and growth cone formation through changes in the local actin cytoskeleton accompanied by increased Ca\(_{v}\)2.2 clustering and local calcium transients. These findings may help to explore cellular mechanisms which might be dysregulated during maturation of embryonic motoneurons leading to motoneuron disease. KW - growth cone KW - BDNF KW - trkB KW - Ca\(_{v}\)2.2 KW - F-actin KW - motor axon Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-159094 VL - 10 IS - 346 ER - TY - JOUR A1 - Dong, Hailong A1 - Kuzmanoski, Ana A1 - Wehner, Tobias A1 - Mueller-Buschbaum, Klaus A1 - Feldmann, Claus T1 - Microwave-assisted polyol synthesis of water dispersible red-emitting Eu\(^{3+}\)-modified carbon dots JF - Materials N2 - Eu\(^{3+}\)-modified carbon dots (C-dots), 3–5 nm in diameter, were prepared, functionalized, and stabilized via a one-pot polyol synthesis. The role of Eu\(^{2+}\)/Eu\(^{3+}\), the influence of O\(_2\) (oxidation) and H\(_2\)O (hydrolysis), as well as the impact of the heating procedure (conventional resistance heating and microwave (MW) heating) were explored. With the reducing conditions of the polyol at the elevated temperature of synthesis (200–230 °C), first of all, Eu\(^{2+}\) was obtained resulting in the blue emission of the C-dots. Subsequent to O\(_2\)-driven oxidation, Eu\(^{3+}\)-modified, red-emitting C-dots were realized. However, the Eu\(^{3+}\) emission is rapidly quenched by water for C-dots prepared via conventional resistance heating. In contrast to the hydroxyl functionalization of conventionally-heated C-dots, MW-heating results in a carboxylate functionalization of the C-dots. Carboxylate-coordinated Eu\(^{3+}\), however, turned out as highly stable even in water. Based on this fundamental understanding of synthesis and material, in sum, a one-pot polyol approach is established that results in H\(_2\)O-dispersable C-dots with intense red Eu\(^{3+}\)-line-type emission. KW - carbon dot KW - europium KW - microwave KW - polyol KW - surface conditioning Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-181674 VL - 10 ER - TY - JOUR A1 - Drenckhahn, Detlev T1 - Vorkommen des Atlantischen Wildkohls (Brassica oleracea L. subsp. oleracea) an den Kreidefelsen der Ostseeinsel Rügen, Deutschland T1 - Occurrence of Atlantic wild cabbage (Brassica oleracea L. subsp. oleracea) at the limestone cliffs of the baltic island of Rügen, Germany JF - Forum Geobotanicum N2 - Der Atlantische Wildkohl (Brassica oleracea L. subsp. oleracea) wächst auf den Küstenfelsen des Atlantiks und der Nordsee zwischen Nord-Spanien, Schottland und der Nordseeinsel Helgoland. 2001 wurde auch ein Vorkommen des Wildkohls an den Kreidefelsen der Ostseeinsel Rügen nachgewiesen, das aus ungefähr 50 Individuen besteht. Die Pflanzen unterscheiden sich phänotypisch nicht von Wildpflanzen der Atlantikküsten. Da alle verbreiteten Kultursorten des Gemüsekohls genetisch sehr eng mit dem Atlantischen Kohl verwandt sind, vom dem sie höchstwahrscheinlich abstammen, wird die Frage erörtert, ob eine spontane Rückverwandlung (Rückkreuzung) von in die Natur entwichenen Kultursorten in den Wildkohl-Phänotyp möglich ist. Dieses wird als wenig wahrscheinlich angesehen. Dagegen ist Introgression zwischen Kultursorten und Wildsorten gut belegt. Die Frage nach einer möglichen Hybridisierung von Grünkohl mit Pflanzen vom Wildkohlphänotyp oder mit anderen Kultursorten an der Kreideküste der dänischen Ostseeinsel Seeland wird anhand eigener Beobachtungen erörtert. Die dortige Population besteht offensichtlich aus verwilderten Kulturkohlhybriden, die sich deutlich von den Wildpflanzen Rügens unterscheiden. Das neue Vorkommen des Atlantischen Wildkohls in der westlichen Ostsee kann im Zusammenhang mit der Ostausbreitung anderer atlantischer Sippen im Rahmen des Klimawandels gesehen werden. N2 - The distribution area of the Atlantic wild cabbage (Brassica oleracea L. subsp. oleracea), hitherto known to be restricted to atlantic coastal cliffs between Northern Spain, Scotland and Helgoland, has expanded this century eastwards to the limestone cliffs of the island of Rügen in the Baltic Sea. The population size is about 50 individuals which are morphologically indistinguishable from Atlantic wild cabbage. The possibility is addressed whether the Rügen population might be derived by backcrossing and naturalization of escaped cultured Brassica oleracea varieties. Genetic studies have shown that the main cultured varieties grown today are closely related to Atlantic wild cabbage from which these varieties were most likely raised. Spontaneous reversal from cultured varieties to the atlantic wild phenotype has often been claimed but not been convincingly demonstrated in the literature and it is considered unlikely that such a full reversal would occur in the absence of crosspollination (introgression) with wild type cabbages. However, introgression of cultured varieties with wild types or naturalization of escaped cultured cole varieties to a more archaic phenotype has been reported. Such an introgression or naturalization process is currently taking place at the limestone coast of Zealand/Denmark. As documented and described in this study, the wild growing coles of Zealand look like descendents of kale and (headed) cabbage and differ considerably from the population of Rügen and Helgoland. The currently observed eastward extension of the atlantic range of wild Brassica oleracea into the Baltic Sea can be interpreted as a more general phenomenon of eastward expansion of the distribution area of other atlantic species in the course of climate warming. KW - Brassica oleracea KW - Atlantischer Wildkohl KW - Kohl Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-142963 UR - http://www.forum-geobotanicum.net/articles/vol_7-2016/drenckhahn_brassica/drenckhahn_brassica_oleracea.pdf SN - 1867-9315 VL - 7 ER - TY - JOUR A1 - Drenckhahn, Detlev A1 - Baumgartner, Werner A1 - Zonneveld, Ben T1 - Different genome sizes of Western and Eastern Ficaria verna lineages shed light on steps of Ficaria evolution JF - Forum Geobotanicum N2 - The genus Ficaria is now considered to comprize eight Eurasian species. The most widespread European species is the tetraploid F. verna Huds. The present study provides evidence for the existence of two main lineages of F. verna that differ considerably in their genomic size by about 3 pg. A Western F. verna lineage west of river Rhine displays a mean genome size (2C-value) of 34.2 pg and is almost precisely codistributed with the diploid F. ambigua Boreau (20 pg) north of the Mediterranean. The remaining part of Europe appears to be occupied by the Eastern F. verna lineage solely (mean genome size of 31.3 pg) which codistributes in South-Eastern Europe with the diploid F. calthifolia Rchb. (15 pg). There is little overlap at the boundary of Western and Eastern F. verna lineages with the occurrence of a separate intermediate group in the Netherlands (mean genomic size of 33.2 pg) that appears to result from hybridization of both lineages. On the basis of these observations and further considerations we propose development of F. ambigua and F. calthifolia south of the Alps with subsequent divergence to populate their current Western and Eastern European ranges, respectively. The Western F. verna lineage is proposed to originate from autotetraploidization of F. ambigua (precursor) with moderate genomic downsizing and the Eastern F. verna lineage from auto¬tetraploidization of F. calthifolia (precursor). KW - Ficaria verna KW - Ficaria calthifolia KW - Ficaria ambigua KW - Durchflusscytometrie KW - Evolution KW - Genom Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-155061 UR - http://www.forum-geobotanicum.net/articles/vol_7-2016/drenckhahn-baumgartner-zonnefeld_ficaria_verna/drenckhahn-baumgartner-zonnefeld_ficaria_verna.pdf SN - 1867-9315 VL - 7 ER - TY - JOUR A1 - Drenckhahn, Detlev A1 - Zonneveld, Ben T1 - Rubus viridilucidus Drenckhahn, eine neue Brombeerart aus der Sektion Corylifolii, Serie Subcanescentes T1 - Rubus viridilucidus Drenckhahn, a new bramble species of the section Corylifolii, series Subcanescentes JF - Forum Geobotanicum N2 - Rubus viridilucidus Drenckhahn ist eine tetraploide Brombeerart (2n=28) aus der Sektion Corylifolii, Serie Subcanescentes mit einem Genomgewicht (2C-Wert) von 1,49 pg, das dem Genomgewicht verwandter Sippen der Serie Subcanescentes wie R. scabrosus, R. fasciculatiformis und R. fasciculatus (1,52–1,54 pg) aus Unterfranken entspricht. Charakteristische Merkmale sind 3–4(5)-zählige Blätter mit herab gekrümmten rundlichen bis breit obovaten Endblättchen und breitovalen Seitenblättchen, die eine völlig unbehaarte, lichtgrüne, mattglänzende Blattoberfläche besitzen mit kontrastierender hell grünlich-grauer, samtig behaarter Blattunterseite. Die überwiegend rundlichen bis stumpf kantigen, lichtgrünen bis rötlich überlaufenen Schösslinge sind unbehaart und spärlich mit kurzen (<4mm) nadelförmigen Stacheln und wenigen Stieldrüsen besetzt. R. viridilucidus entwickelt zusätzlich zu den Blütenzweigen der zweijährigen Schösslinge (Ausbreitungsschösslinge) einen besonderen blühenden 0,8 bis 1,6 m langen Schösslingstyp aus, den Rispenschössling, der direkt aus dem Wurzelstock entspringt und terminal in eine Blütenrispe ausläuft. Bei R. viridilucidus sind zwei verschiedene Typen von Rispenschösslingen ausgebildet. Die Sippe wächst bevorzugt auf gestörten Flächen wie Brachen, Straßenrändern, Lagerplätzen, Weinbergrändern und kann sich mit 1–2 m jährlichem Zuwachs (Satellitenbildauswertung, Vermessungen vor Ort) schnell ausbreiten. Die bekannt gewordenen Fundstellen erstrecken sich vom nördlichen Baden-Württemberg bis in den nördlichsten Teil von Bayern (Rhön). N2 - Rubus viridilucidus Drenckhahn is a new member of the Rubus section Corylifolii, series Subcanescentes, with an average tetraploid set of chromosomes (2n=28) and a genome size of 1.49 pg that matches the genome size of the related species of the series Subcanescentes R. scabrosus, R. fasciculatiformis and R. fasciculatus (1.52–1.54 pg). This species is distinguished by 3 to 4(5)-nate leaves with down curved roundish to broad obovate terminal and broad lateral leaflets with lucid-green glabrous upper side and light greenish grey, velvety pubescent lower side. Stems are roundish to obtusely angled, glabrous, green to reddish coloured, and armed sparsely with short, needle-like prickles (<4mm) and stalked glands. R. viridilucidus develops a second type of stem – denoted as panicle shoot – that is 0.8–1.6 m long, emerges directly from the rootstock and terminates apically in an inflorescence. Panicle shoots occur in R. viridilucidus in two varieties. The species prefers fallow land, quarries, road sides and margins of vineyards. It has a remarkable capability of propagation (about 1–2 m/year) as documented on the basis of satellite image (Google Earth) in combination with on-site surveys. The distribution area of R. viridilucidus, known so far, extends from Northern Baden-Württemberg to the most northern edge of Bavaria (Rhön mountains). KW - Brombeerart KW - Vorkommen KW - Rubus viridilucidus KW - Brombeere KW - Rubus KW - Unterfranken KW - Karyotyp Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-156257 UR - http://www.forum-geobotanicum.net/articles/vol_7-2016/drenckhahn-zonneveld_rubus_viridilucidus/drenckhahn-zonneveld_rubus_viridilucidus.pdf SN - 1867-9315 VL - 7 ER - TY - JOUR A1 - Drescher, Nora A1 - Klein, Alexandra-Maria A1 - Neumann, Peter A1 - Yañez, Orlando A1 - Leonhardt, Sara D. T1 - Inside Honeybee Hives: Impact of Natural Propolis on the Ectoparasitic Mite Varroa destructor and Viruses JF - Insects N2 - Social immunity is a key factor for honeybee health, including behavioral defense strategies such as the collective use of antimicrobial plant resins (propolis). While laboratory data repeatedly show significant propolis effects, field data are scarce, especially at the colony level. Here, we investigated whether propolis, as naturally deposited in the nests, can protect honeybees against ectoparasitic mites Varroa destructor and associated viruses, which are currently considered the most serious biological threat to European honeybee subspecies, Apis mellifera, globally. Propolis intake of 10 field colonies was manipulated by either reducing or adding freshly collected propolis. Mite infestations, titers of deformed wing virus (DWV) and sacbrood virus (SBV), resin intake, as well as colony strength were recorded monthly from July to September 2013. We additionally examined the effect of raw propolis volatiles on mite survival in laboratory assays. Our results showed no significant effects of adding or removing propolis on mite survival and infestation levels. However, in relation to V. destructor, DWV titers increased significantly less in colonies with added propolis than in propolis-removed colonies, whereas SBV titers were similar. Colonies with added propolis were also significantly stronger than propolis-removed colonies. These findings indicate that propolis may interfere with the dynamics of V. destructor-transmitted viruses, thereby further emphasizing the importance of propolis for honeybee health. KW - social immunity KW - Apis mellifera KW - deformed wing virus KW - plant-insect interactions KW - resin KW - sacbrood virus Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-171164 VL - 8 IS - 1 ER - TY - JOUR A1 - Dziom, V. A1 - Shuvaev, A. A1 - Pimenov, A. A1 - Astakhov, G.V. A1 - Ames, C. A1 - Bendias, K. A1 - Böttcher, J. A1 - Tkachov, G. A1 - Hankiewicz, E.M. A1 - Brüne, C. A1 - Buhmann, H. A1 - Molenkamp, L.W. T1 - Observation of the universal magnetoelectric effect in a 3D topological insulator JF - Nature Communications N2 - The electrodynamics of topological insulators (TIs) is described by modified Maxwell’s equations, which contain additional terms that couple an electric field to a magnetization and a magnetic field to a polarization of the medium, such that the coupling coefficient is quantized in odd multiples of α/4π per surface. Here we report on the observation of this so-called topological magnetoelectric effect. We use monochromatic terahertz (THz) spectroscopy of TI structures equipped with a semitransparent gate to selectively address surface states. In high external magnetic fields, we observe a universal Faraday rotation angle equal to the fine structure constant α=e\(^{2}\)/2E\(_{0}\)hc (in SI units) when a linearly polarized THz radiation of a certain frequency passes through the two surfaces of a strained HgTe 3D TI. These experiments give insight into axion electrodynamics of TIs and may potentially be used for a metrological definition of the three basic physical constants. KW - topological matter KW - infrared spectroscopy KW - topological insulators KW - topological magnetoelectric effect Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170875 VL - 8 IS - 15197 ER - TY - JOUR A1 - Döhler, Anja A1 - Schneider, Theresa A1 - Eckert, Ina A1 - Ribechini, Eliana A1 - Andreas, Nico A1 - Riemann, Marc A1 - Reizis, Boris A1 - Weih, Falk A1 - Lutz, Manfred B. T1 - RelB\(^{+}\) Steady-State Migratory Dendritic Cells Control the Peripheral Pool of the Natural Foxp3\(^{+}\) Regulatory T Cells JF - Frontiers in Immunology N2 - Thymus-derived natural Foxp3\(^{+}\) CD4\(^{+}\) regulatory T cells (nTregs) play a key role in maintaining immune tolerance and preventing autoimmune disease. Several studies indicate that dendritic cells (DCs) are critically involved in the maintenance and proliferation of nTregs. However, the mechanisms how DCs manage to keep the peripheral pool at constant levels remain poorly understood. Here, we describe that the NF-κB/Rel family transcription factor RelB controls the frequencies of steady-state migratory DCs (ssmDCs) in peripheral lymph nodes and their numbers control peripheral nTreg homeostasis. DC-specific RelB depletion was investigated in CD11c-Cre × RelB\(^{fl/fl}\) mice (RelB\(^{DCko}\)), which showed normal frequencies of resident DCs in lymph nodes and spleen while the subsets of CD103\(^{-}\) Langerin\(^{-}\) dermal DCs (dDCs) and Langerhans cells but not CD103\(^{+}\) Langerin\(^{+}\) dDC of the ssmDCs in skin-draining lymph nodes were increased. Enhanced frequencies and proliferation rates were also observed for nTregs and a small population of CD4\(^{+}\) CD44\(^{high}\) CD25\(^{low}\) memory-like T cells (Tml). Interestingly, only the Tml but not DCs showed an increase in IL-2-producing capacity in lymph nodes of RelB\(^{DCko}\) mice. Blocking of IL-2 in vivo reduced the frequency of nTregs but increased the Tml frequencies, followed by a recovery of nTregs. Taken together, by employing RelB\(^{DCko}\) mice with increased frequencies of ssmDCs our data indicate a critical role for specific ssmDC subsets for the peripheral nTreg and IL-2\(^{+}\) Tml frequencies during homeostasis. KW - lymph nodes KW - dendritic cells KW - RelB KW - regulatory T cells KW - IL-2 Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-158121 VL - 8 IS - 726 ER -