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Many snake venoms are known for their antithrombotic activity. They contain components that specifically target different platelet-activating receptors such as the collagen-binding integrin α2β1 and the von Willebrand factor receptor GPIb. In a search for an α2β1 integrin-blocking component from the venom of the habu snake (Trimeresurus flavoviridis), we employed two independent purification protocols. First, we used the integrin α2A domain, a major collagen-binding domain, as bait for affinity purification of an α2β1 integrin-binding toxin from the crude venom. Second, in parallel, we used classical protein separation protocols and tested for α2β1 integrin-inhibiting capabilities by ELISA. Using both approaches, we identified flavocetin-A as an inhibitor of α2β1 integrin. Hitherto, flavocetin-A has been reported as a GPIb inhibitor. However, flavocetin-A inhibited collagen-induced platelet aggregation even after GPIb was blocked with other inhibitors. Moreover, flavocetin-A antagonized α2β1 integrin-mediated adhesion and migration of HT1080 human fibrosarcoma cells, which lack any GPIb, on collagen. Protein chemical analyses proved that flavocetin-A binds to α2β1 integrin and its α2A domain with high affinity and in a cooperative manner, which most likely is due to its quaternary structure. Kinetic measurements confirmed the formation of a strong complex between integrin and flavocetin-A, which dissociates very slowly. This study proves that flavocetin-A, which has long been known as a GPIb inhibitor, efficiently targets α2β1 integrin and thus blocks collagen-induced platelet activation. Moreover, our findings suggest that the separation of GPIb- and α2β1 integrin-blocking members within the C-type lectin-related protein family is less strict than previously assumed.
Recht und die Vorstellung von dem, was Recht ist, sind nicht allein an Territorien oder Herrschaften gebunden, sondern wandern mit den Menschen mit. Treffen mehrere möglicherweise anwendbare Rechte aufeinander, steht für heutige Gerichte ein Kollisionsrecht wie das Internationale Privatrecht bereit, dass über den Umgang mit diesem Konflikt entscheidet , indem es den Fall einer bestimmten nationalstaatlichen Regelung unterstellt. Andere Lösungen sind jedoch ebenfalls denkbar und wurden in der Vergangenheit auch praktiziert, was heute schwer nachzuvollziehen ist. Um die Denkstruktur und Grenzen der modernen Herangehensweise deutlich werden zu lassen, sollen in diesem Beitrag die Schwierigkeiten erläutert werden, das Konzept des Internationalen Privatrechts auf das Neben- und Miteinander verschiedener rechtlicher Traditionen im hellenistischen Ägypten zu übertragen. Ziel ist es, auch Nichtjuristen damit einen Einstieg und eine Übersicht über die Diskussion innerhalb der antiken Rechtsgeschichte zu ermöglichen.
Seed dispersal is hard to measure, and there is still a lack of knowledge about dispersal-related traits of plant species. Therefore, we developed D3, the Dispersal and Diaspore Database (available at
www.seed-dispersal.info), which aims at simplifying ecological and evolutionary analyses by providing and integrating various items related to seed dispersal: empirical studies, functional traits, image analyses and ranking indices (quantifying the adaptation to dispersal modes).
Currently, the database includes data for more than 5000 taxa and 33 items as well as digital images of diaspores (i.e. the dispersal units), seeds, fruits and infructescences. The included items cover common traits like diaspore mass, size, shape, terminal velocity and seed number per diaspore. Furthermore, we present newly or further developed items like ecomorphological categorizations of the diaspore and fruit as well as information from literature on prevailing dispersal modes. Finally, we introduce several items which are not covered in other databases yet: surface structure and form of the diaspore, the exposure of the diaspores in the infructescence and dispersal rankings. Dispersal rankings allow estimations of how well certain species are adapted to a specific dispersal mode in comparison to a larger species set. They are calculated as the percentile rank of an indicator of species’ dispersal potential in relation to a larger species set.
Especially for the new and further developed items we outline the basic concepts in detail, describe the measurement and categorization methods and show how to interpret and integrate these data for single species as well as for larger species sets. Thereby, we calculate baseline statistics of seed dispersal of the Central European flora. We found that diaspores of 72% of the taxa show specializations related to long-distance dispersal, i.e. most often elongated appendages or nutrient-rich tissues. Diaspore masses, sizes and terminal velocities vary over several orders of magnitude and can be approximated by lognormal distributions.
The Sino-Tibetan language family enshrines the migratory histories of many East Asian populations, including the Chinese, Tibetans, and Burmese. Its history is intimately associated with Neolithic and Bronze Age developments in China itself, and today it is one of the major world language families in terms of population numbers.
Im vorliegenden Beitrag werde ich die soziologischen und linguistischen theoretischmethodischen Ansätze der Komikforschung kurz skizzieren, um zu zeigen, dass sich Komik als Mittel für eine soziologische bzw. interaktionistische Forschung durchaus eignet, und werde danach auf den Zusammenhang von Komik, Kultur und Gesellschaft überleiten. Auf dieser Basis möchte ich die Potentiale der Komik für die Erforschung der Beziehungen zwischen Einheimischen und Zugewanderten in Deutschland anhand der Beispiele der Spätaussiedler sowie der Deutsch-Türken auf einem neuen Wege - nämlich in Bezug auf die sozialen Funktionen von Komik - aufzeigen. Es wird nachgewiesen, dass Komik ein soziales, kultur- und kontextabhängiges, in den Alltag eingebettetes Phänomen darstellt, da sie bei den Beteiligten nicht nur die Bildung von In- und Out-Group, sondern auch einen ungezwungenen Perspektivenwechsel und die Revision eigener Wissensbestände ermöglicht. Aus diesen Gründen eignet sie sich in besonderer Weise als Gegenstand für die Erforschung inter- und intraethnischer Beziehungen.
In this article we review a variety of methods to enable understanding and modelling the spread of a pest or pathogen post-entry. Building upon our experience of multidisciplinary research in this area, we propose practical guidelines and a framework for model development, to help with the application of mathematical modelling in the field of invasion ecology for post-entry spread. We evaluate the pros and cons of a range of methods, including references to examples of the methods in practice. We also show how issues of data deficiency and uncertainty can be addressed. The aim is to provide guidance to the reader on the most suitable elements to include in a model of post-entry dispersal in a risk assessment, under differing circumstances. We identify both the strengths and weaknesses of different methods and their application as part of a holistic, multidisciplinary approach to biosecurity research.
Transylvanian Saxons' migration from Romania to Germany: the formation of a 'return' diaspora?
(2013)
Processes and patterns of migration on a global scale have changed in profound ways during the last two decades (Smith and King, 2012). In the European context, this is exemplified by transformations to the traditional mobility patterns from East to West Europe (Koser and Lutz, 1998), with migrants more likely to be involved in temporary circular and transnational mobility (Favell, 2008). Since the end of the Second World War, historical and political events in Europe have facilitated the mobility of ethnic Germans from Eastern Europe to Germany. Subsequently, the fall of the Iron Curtain has permitted unrestrained East-West movements, which resulted in mass migrations towards the West and diaspora fragments in the East. However, after settlement in the West, ethnic Germans have also been absorbed within wider temporary and transnational movements (Koser, 2007). Within this context, this thesis examines the post-migratory lives of three generations of Transylvanian Saxons in Germany by exploring the cultural, social, economic and political dimensions of this community. This thesis aims to contribute to on-going academic debates about diasporas by explicitly responding to Hoerder s (2002) call for more studies on ethnic German diasporas. It shows that Transylvanian Saxons, who relocated to the ancestral homeland, do not disrupt identities and lives forged in diaspora, but rather, they negotiate complex identities and belongings in relation to both home and homeland . It reveals a double diaspora and the necessity to perceive identity and diaspora as dynamic processes and constantly evolving in relation to time, space and place. This double diasporic allegiance in the case of the Transylvanian Saxons suggests interrogating the formation of a return diaspora and its importance for processes of international migration.
Vascular endothelial growth factors (VEGFs), initially thought to act specifically on the vascular system, exert trophic effects on neural cells during development and adulthood. Therefore, the VEGF system serves as a promising therapeutic target for brain pathologies, but its simultaneous action on vascular cells paves the way for harmful side effects. To circumvent these deleterious effects, many studies have aimed to clarify whether VEGFs directly affect neural cells or if the effects are mediated secondarily via other cell types, like vascular cells. A great number of reports have shown the expression and function of VEGF receptors (VEGFRs), mainly VEGFR-1 and -2, in neural cells, where VEGFR-2 has been described as the major mediator of VEGF-A signals. This review aims to summarize and compare the divergent roles of VEGFR-1 and -2 during CNS development and homeostasis.