@article{UestuenBartetzkoBoernke2015, author = {{\"U}st{\"u}n, Suayib and Bartetzko, Verena and B{\"o}rnke, Frederik}, title = {The Xanthomonas effector XopJ triggers a conditional hypersensitive response upon treatment of N. benthamiana leaves with salicylic acid}, series = {Frontiers in plant science}, volume = {6}, journal = {Frontiers in plant science}, publisher = {Frontiers Research Foundation}, address = {Lausanne}, issn = {1664-462X}, doi = {10.3389/fpls.2015.00599}, pages = {11}, year = {2015}, abstract = {XopJ is a Xanthomonas type III effector protein that promotes bacterial virulence on susceptible pepper plants through the inhibition of the host cell proteasome and a resultant suppression of salicylic acid (SA) - dependent defense responses. We show here that Nicotiana benthamiana leaves transiently expressing XopJ display hypersensitive response (HR) -like symptoms when exogenously treated with SA. This apparent avirulence function of XopJ was further dependent on effector myristoylation as well as on an intact catalytic triad, suggesting a requirement of its enzymatic activity for HR-like symptom elicitation. The ability of XopJ to cause a HR-like symptom development upon SA treatment was lost upon silencing of SGT1 and NDR1, respectively, but was independent of EDS1 silencing, suggesting that XopJ is recognized by an R protein of the CC-NBS-LRR class. Furthermore, silencing of NPR1 abolished the elicitation of HR-like symptoms in XopJ expressing leaves after SA application. Measurement of the proteasome activity indicated that proteasome inhibition by XopJ was alleviated in the presence of SA, an effect that was not observed in NPR1 silenced plants. Our results suggest that XopJ - triggered HR-like symptoms are closely related to the virulence function of the effector and that XopJ follows a two-signal model in order to elicit a response in the non-host plant N. benthamiana.}, language = {en} } @article{ZuehlkeRiebeBeitzetal.2015, author = {Z{\"u}hlke, Martin and Riebe, Daniel and Beitz, Toralf and L{\"o}hmannsr{\"o}ben, Hans-Gerd and Zenichowski, Karl and Diener, Marc and Linscheid, Michael W.}, title = {An electrospray ionization-ion mobility spectrometer as detector for high-performance liquid chromatography}, series = {European journal of mass spectrometry}, volume = {21}, journal = {European journal of mass spectrometry}, number = {3}, publisher = {WeltTrends}, address = {Sussex}, issn = {1469-0667}, doi = {10.1255/ejms.1367}, pages = {391 -- 402}, year = {2015}, abstract = {The application of electrospray ionization (ESI) ion mobility (IM) spectrometry on the detection end of a high-performance liquid chromatograph has been a subject of study for some time. So far, this method has been limited to low flow rates or has required splitting of the liquid flow. This work presents a novel concept of an ESI source facilitating the stable operation of the spectrometer at flow rates between 10 mu L min(-1) and 1500 mu L min(-1) without flow splitting, advancing the T-cylinder design developed by Kurnin and co-workers. Flow rates eight times faster than previously reported were achieved because of a more efficient dispersion of the liquid at increased electrospray voltages combined with nebulization by a sheath gas. Imaging revealed the spray operation to be in a rotationally symmetric multijet-mode. The novel ESI-IM spectrometer tolerates high water contents (<= 90\%) and electrolyte concentrations up to 10 mM, meeting another condition required of high-performance liquid chromatography (HPLC) detectors. Limits of detection of 50 nM for promazine in the positive mode and 1 mu M for 1,3-dinitrobenzene in the negative mode were established. Three mixtures of reduced complexity (five surfactants, four neuroleptics, and two isomers) were separated in the millisecond regime in stand-alone operation of the spectrometer. Separations of two more complex mixtures (five neuroleptics and 13 pesticides) demonstrate the application of the spectrometer as an HPLC detector. The examples illustrate the advantages of the spectrometer over the established diode array detector, in terms of additional IM separation of substances not fully separated in the retention time domain as well as identification of substances based on their characteristic IMs.}, language = {en} } @article{ZurellEggersKaatzetal.2015, author = {Zurell, Damaris and Eggers, Ute and Kaatz, Michael and Rotics, Shay and Sapir, Nir and Wikelski, Martin and Nathan, Ran and Jeltsch, Florian}, title = {Individual-based modelling of resource competition to predict density-dependent population dynamics: a case study with white storks}, series = {Oikos}, volume = {124}, journal = {Oikos}, number = {3}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0030-1299}, doi = {10.1111/oik.01294}, pages = {319 -- 330}, year = {2015}, abstract = {Density regulation influences population dynamics through its effects on demographic rates and consequently constitutes a key mechanism explaining the response of organisms to environmental changes. Yet, it is difficult to establish the exact form of density dependence from empirical data. Here, we developed an individual-based model to explore how resource limitation and behavioural processes determine the spatial structure of white stork Ciconia ciconia populations and regulate reproductive rates. We found that the form of density dependence differed considerably between landscapes with the same overall resource availability and between home range selection strategies, highlighting the importance of fine-scale resource distribution in interaction with behaviour. In accordance with theories of density dependence, breeding output generally decreased with density but this effect was highly variable and strongly affected by optimal foraging strategy, resource detection probability and colonial behaviour. Moreover, our results uncovered an overlooked consequence of density dependence by showing that high early nestling mortality in storks, assumed to be the outcome of harsh weather, may actually result from density dependent effects on food provision. Our findings emphasize that accounting for interactive effects of individual behaviour and local environmental factors is crucial for understanding density-dependent processes within spatially structured populations. Enhanced understanding of the ways animal populations are regulated in general, and how habitat conditions and behaviour may dictate spatial population structure and demographic rates is critically needed for predicting the dynamics of populations, communities and ecosystems under changing environmental conditions.}, language = {en} } @article{ZouSchlaad2015, author = {Zou, Hua and Schlaad, Helmut}, title = {Thermoresponsive PNIPAM/Silica Nanoparticles by Direct Photopolymerization in Aqueous Media}, series = {Journal of polymer science : A, Polymer chemistry}, volume = {53}, journal = {Journal of polymer science : A, Polymer chemistry}, number = {10}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0887-624X}, doi = {10.1002/pola.27593}, pages = {1260 -- 1267}, year = {2015}, abstract = {This article presents a simple and facile method to fabricate thermoresponsive polymer-grafted silica particles by direct surface-initiated photopolymerization of N-isopropylacrylamide (NIPAM). This method is based on silica particles bearing thiol functionalities, which are transformed into thiyl radicals by irradiation with UV light to initiate the polymerization of NIPAM in aqueous media at room temperature. The photopolymerization of NIPAM could be applied to smaller thiol-functionalized particles (approximate to 48 nm) as well as to larger particles (approximate to 692 nm). Hollow poly(NIPAM) capsules could be formed after etching away the silica cores from the composite particles. It is possible to produce tailor-made composite particles or capsules for particular applications by extending this approach to other vinyl monomers. (c) 2015 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 2015, 53, 1260-1267}, language = {en} } @article{ZirafiKimStaendkeretal.2015, author = {Zirafi, Onofrio and Kim, Kyeong-Ae and St{\"a}ndker, Ludger and Mohr, Katharina B. and Sauter, Daniel and Heigele, Anke and Kluge, Silvia F. and Wiercinska, Eliza and Chudziak, Doreen and Richter, Rudolf and M{\"o}pps, Barbara and Gierschik, Peter and Vas, Virag and Geiger, Hartmut and Lamla, Markus and Weil, Tanja and Burster, Timo and Zgraja, Andreas and Daubeuf, Francois and Frossard, Nelly and Hachet-Haas, Muriel and Heunisch, Fabian and Reichetzeder, Christoph and Galzi, Jean-Luc and Perez-Castells, Javier and Canales-Mayordomo, Angeles and Jimenez-Barbero, Jesus and Gimenez-Gallego, Guillermo and Schneider, Marion and Shorter, James and Telenti, Amalio and Hocher, Berthold and Forssmann, Wolf-Georg and Bonig, Halvard and Kirchhoff, Frank and M{\"u}nch, Jan}, title = {Discovery and Characterization of an Endogenous CXCR4 Antagonist}, series = {Cell reports}, volume = {11}, journal = {Cell reports}, number = {5}, publisher = {Cell Press}, address = {Cambridge}, issn = {2211-1247}, doi = {10.1016/j.celrep.2015.03.061}, pages = {737 -- 747}, year = {2015}, abstract = {CXCL12-CXCR4 signaling controls multiple physiological processes and its dysregulation is associated with cancers and inflammatory diseases. To discover as-yet-unknown endogenous ligands of CXCR4, we screened a blood-derived peptide library for inhibitors of CXCR4-tropic HIV-1 strains. This approach identified a 16 amino acid fragment of serum albumin as an effective and highly specific CXCR4 antagonist. The endogenous peptide, termed EPI-X4, is evolutionarily conserved and generated from the highly abundant albumin precursor by pH-regulated proteases. EPI-X4 forms an unusual lasso-like structure and antagonizes CXCL12-induced tumor cell migration, mobilizes stem cells, and suppresses inflammatory responses in mice. Furthermore, the peptide is abundant in the urine of patients with inflammatory kidney diseases and may serve as a biomarker. Our results identify EPI-X4 as a key regulator of CXCR4 signaling and introduce proteolysis of an abundant precursor protein as an alternative concept for chemokine receptor regulation.}, language = {en} } @article{ZimmermannNey2015, author = {Zimmermann, Andreas and Ney, Martin}, title = {Cyber-Security beyond the military perspective: International Law 'cyber space' and the concept of due diligence.}, series = {German Yearbook of International Law}, volume = {58}, journal = {German Yearbook of International Law}, publisher = {Duncker \& Humblot}, address = {Berlin}, pages = {51 -- 66}, year = {2015}, language = {en} } @article{Zimmermann2015, author = {Zimmermann, Andreas}, title = {The Palestinian-Israeli Conflict: Developing International Law Without Solving the Conflict}, series = {Archiv des V{\"o}lkerrechts}, volume = {53}, journal = {Archiv des V{\"o}lkerrechts}, number = {2}, publisher = {Mohr Siebeck}, address = {T{\"u}bingen}, doi = {10.1628/000389215X14412717564749}, pages = {149 -- 166}, year = {2015}, abstract = {The article analyses whether the Palestinian-Israeli conflict has served as a catalyst for the development of international law, as well as whether international law has been instrumental in attempting to find solutions for the said conflict. In several ways, this conflict has made a significant contribution to understanding and interpreting the UN Charter. It also brought along important developments about the role of third parties, both under the Geneva Conventions and under the law of state responsibility, which provides for an obligation of not recognizing as legal, or not rendering aid or assistance to situations caused by serious violations of jus cogens. International judicial institutions (and also domestic ones) play a rather limited role in this respect, due both to a lack of courage to address fundamental questions, and/or a disregard of the outcome of the proceedings by at least one of the parties to the conflict. Other reasons are Israel's reluctance of accepting the jurisdiction of either the ICJ or the ICC, and its view on the non-applicability of human rights treaties outside of its territory, as well as Palestine's uncertain status in the international community limiting its access to international courts. However, the ICJ's 2004 (formally non-binding) advisory opinion on the Israeli Wall provided answers to some of the most fundamental questions related to the conflict, unfortunately without having any immediate impact on the situation on the ground. Given Palestine's accession to the Rome Statute in early 2015, time has yet to show which role in the process will be played by the ICC. Other issues arising from the conflict, and examined by this article, are that of (Palestinian) statehood, going beyond the traditional concept of statehood and including the consequences of the jus cogens-character of the right of self-determination, as well as questions of treaty succession and succession in matters of State responsibility with regard to acts committed by the PLO.}, language = {en} } @article{ZimmermannUberZimmermannetal.2015, author = {Zimmermann, Alexander and Uber, Magdalena and Zimmermann, Beate and Levia, Delphis F.}, title = {Predictability of stemflow in a species-rich tropical forest}, series = {Hydrological processes}, volume = {29}, journal = {Hydrological processes}, number = {23}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0885-6087}, doi = {10.1002/hyp.10554}, pages = {4947 -- 4956}, year = {2015}, abstract = {Numerous studies investigated the influence of abiotic (meteorological conditions) and biotic factors (tree characteristics) on stemflow generation. Although these studies identified the variables that influence stemflow volumes in simply structured forests, the combination of tree characteristics that allows a robust prediction of stemflow volumes in species-rich forests is not well known. Many hydrological applications, however, require at least a rough estimate of stemflow volumes based on the characteristics of a forest stand. The need for robust predictions of stemflow motivated us to investigate the relationships between tree characteristics and stemflow volumes in a species-rich tropical forest located in central Panama. Based on a sampling setup consisting of ten rainfall collectors, 300 throughfall samplers and 60 stemflow collectors and cumulated data comprising 26 rain events, we derive three main findings. Firstly, stemflow represents a minor hydrological component in the studied 1-ha forest patch (1.0\% of cumulated rainfall). Secondly, in the studied species-rich forest, single tree characteristics are only weakly related to stemflow volumes. The influence of multiple tree parameters (e.g. crown diameter, presence of large epiphytes and inclination of branches) and the dependencies among these parameters require a multivariate approach to understand the generation of stemflow. Thirdly, predicting stemflow in species-rich forests based on tree parameters is a difficult task. Although our best model can capture the variation in stemflow to some degree, a critical validation reveals that the model cannot provide robust predictions of stemflow. A reanalysis of data from previous studies in species-rich forests corroborates this finding. Based on these results and considering that for most hydrological applications, stemflow is only one parameter among others to estimate, we advocate using the base model, i.e. the mean of the stemflow data, to quantify stemflow volumes for a given study area. Studies in species-rich forests that wish to obtain predictions of stemflow based on tree parameters probably need to conduct a much more extensive sampling than currently implemented by most studies. Copyright (c) 2015 John Wiley \& Sons, Ltd.}, language = {en} } @article{ZierisGerstbergerMueller2015, author = {Zieris, Holger and Gerstberger, Herbert and M{\"u}ller, Wolfgang}, title = {Using Arduino-Based Experiments to Integrate Computer Science Education and Natural Science}, series = {KEYCIT 2014 - Key Competencies in Informatics and ICT}, journal = {KEYCIT 2014 - Key Competencies in Informatics and ICT}, number = {7}, publisher = {Universit{\"a}tsverlag Potsdam}, address = {Potsdam}, issn = {1868-0844}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-82938}, pages = {381 -- 389}, year = {2015}, abstract = {Current curricular trends require teachers in Baden- Wuerttemberg (Germany) to integrate Computer Science (CS) into traditional subjects, such as Physical Science. However, concrete guidelines are missing. To fill this gap, we outline an approach where a microcontroller is used to perform and evaluate measurements in the Physical Science classroom. Using the open-source Arduino platform, we expect students to acquire and develop both CS and Physical Science competencies by using a self-programmed microcontroller. In addition to this combined development of competencies in Physical Science and CS, the subject matter will be embedded in suitable contexts and learning environments, such as weather and climate.}, language = {en} } @article{ZieglerReiterHeidbachetal.2015, author = {Ziegler, Moritz O. and Reiter, Karsten and Heidbach, Oliver and Zang, Arno and Kwiatek, Grzegorz and Stromeyer, Dietrich and Dahm, Torsten and Dresen, Georg and Hofmann, Gerhard}, title = {Mining-Induced Stress Transfer and Its Relation to a 1.9 Seismic Event in an Ultra-deep South African Gold Mine}, series = {Pure and applied geophysics}, volume = {172}, journal = {Pure and applied geophysics}, number = {10}, publisher = {Springer}, address = {Basel}, issn = {0033-4553}, doi = {10.1007/s00024-015-1033-x}, pages = {2557 -- 2570}, year = {2015}, abstract = {On 27 December 2007, a 1.9 seismic event occurred within a dyke in the deep-level Mponeng Gold Mine, South Africa. From the seismological network of the mine and the one from the Japanese-German Underground Acoustic Emission Research in South Africa (JAGUARS) group, the hypocentral depth (3,509 m), focal mechanism and aftershock location were estimated. Since no mining activity took place in the days before the event, dynamic triggering due to blasting can be ruled out as the cause. To investigate the hypothesis that stress transfer, due to excavation of the gold reef, induced the event, we set up a small-scale high-resolution three-dimensional (3D) geomechanical numerical model. The model consisted of the four different rock units present in the mine: quartzite (footwall), hard lava (hanging wall), conglomerate (gold reef) and diorite (dykes). The numerical solution was computed using a finite-element method with a discretised mesh of approximately elements. The initial stress state of the model is in agreement with in situ data from a neighbouring mine, and the step-wise excavation was simulated by mass removal from the gold reef. The resulting 3D stress tensor and its changes due to mining were analysed based on the Coulomb failure stress changes on the fault plane of the event. The results show that the seismic event was induced regardless of how the Coulomb failure stress changes were calculated and of the uncertainties in the fault plane solution. We also used the model to assess the seismic hazard due to the excavation towards the dyke. The resulting curve of stress changes shows a significant increase in the last in front of the dyke, indicating that small changes in the mining progress towards the dyke have a substantial impact on the stress transfer.}, language = {en} }