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Analysis of knockout/knockin mice that express a mutant FasL lacking the intracellular domain
(2009)
Fas ligand (FasL; CD178; CD95L) is a type II transmembrane protein belonging to the tumour necrosis factor family; its binding to the Fas receptor (CD95; APO-1) triggers apoptosis in the receptor-bearing cell. Signalling through this pathway plays a pivotal role during the immune response and in immune system homeostasis. Similar to other TNF family members, the intracellular domain has been reported to transmit signals to the inside of the FasL-bearing cell (reverse signalling). Recently, we identified the proteases ADAM10 and SPPL2a as molecules important for the processing of FasL. Protease cleavage releases the intracellular domain, which then is able to translocate to the nucleus and to repress reporter gene activity. To study the physiological importance of FasL reverse signalling in vivo, we established knockout/knockin mice with a FasL deletion mutant that lacks the intracellular portion (FasLDeltaIntra). Co-culture experiments confirmed that the truncated FasL protein is still capable of inducing apoptosis in Fas-sensitive cells. Preliminary immune histochemistry data suggest that, in contrast to published data, the absence of the intracellular FasL domain does not alter the intracellular FasL localization in activated T cells. We are currently investigating signalling and proliferative capacities of T cells derived from homozygous FasLDeltaIntra mice to validate a co-stimulatory role of FasL reverse signalling.
The ongoing digitalization of educational resources and the use of the internet lead to a steady increase of potentially available learning media. However, many of the media which are used for educational purposes have not been designed specifically for teaching and learning. Usually, linguistic criteria of readability and comprehensibility as well as content-related criteria are used independently to assess and compare the quality of educational media. This also holds true for educational media used in economics. This article aims to improve the analysis of textual learning media used in economic education by drawing on threshold concepts. Threshold concepts are key terms in knowledge acquisition within a domain. From a linguistic perspective, however, threshold concepts are instances of specialized vocabularies, exhibiting particular linguistic features. In three kinds of (German) resources, namely in textbooks, in newspapers, and on Wikipedia, we investigate the distributive profiles of 63 threshold concepts identified in economics education (which have been collected from threshold concept research). We looked at the threshold concepts' frequency distribution, their compound distribution, and their network structure within the three kinds of resources. The two main findings of our analysis show that firstly, the three kinds of resources can indeed be distinguished in terms of their threshold concepts' profiles. Secondly, Wikipedia definitely shows stronger associative connections between economic threshold concepts than the other sources. We discuss the findings in relation to adequate media use for teaching and learning—not only in economic education.
Biodiversity information is contained in countless digitized and unprocessed scholarly texts. Although automated extraction of these data has been gaining momentum for years, there are still innumerable text sources that are poorly accessible and require a more advanced range of methods to extract relevant information. To improve the access to semantic biodiversity information, we have launched the BIOfid project (www.biofid.de) and have developed a portal to access the semantics of German language biodiversity texts, mainly from the 19th and 20th century. However, to make such a portal work, a couple of methods had to be developed or adapted first. In particular, text-technological information extraction methods were needed, which extract the required information from the texts. Such methods draw on machine learning techniques, which in turn are trained by learning data. To this end, among others, we gathered the BIOfid text corpus, which is a cooperatively built resource, developed by biologists, text technologists, and linguists. A special feature of BIOfid is its multiple annotation approach, which takes into account both general and biology-specific classifications, and by this means goes beyond previous, typically taxon- or ontology-driven proper name detection. We describe the design decisions and the genuine Annotation Hub Framework underlying the BIOfid annotations and present agreement results. The tools used to create the annotations are introduced, and the use of the data in the semantic portal is described. Finally, some general lessons, in particular with multiple annotation projects, are drawn.
Se presenta un resumen del estado actual de investigaciones sobre líquenes foliícolas en la región Neotrópica. Historicamente, se puede hacer una división en (1) el período inicial, dominado por las obras de J. Müller Argoviensis, (2) la monografía de R. Santesson, (3) la fase brasileña, caracterizada por el micólogo Brasileño A. C. Batista y sus colaboradores, y (4) el período moderno, con estudios detallados monográficos y florísticos y un creciente interés en la ecología de líquenes foliícolas. Actualmente tenemos un conocimiento -taxonómico y sistemático relativamente bueno en la mayoría de los grupos, aunque nuevas espécies son descritas continuamente y algunas familias y géneros necesitan revisiones. Información florística detallada existe solamente de pocas regiones, y por esa razon los datos biogeográficos quedan incompletos y controversos. Estudios ecológicos modernos fueron realizados en varias ocasiones, pero falta verificar los resultados por estudios extensivas en otras regiones dentro y fuera del Neotrópico. Investigaciones preliminares demuestran que los líquenes foliícolas pueden ser usados como bioindicadores en diferentes formas. Biogeograficamente, la región Neotrópica esta caracterizada por un alto número de espécies exclusivos y por su afinidad con África tropical. Debido a la amplia distribución de muchos taxa y al déficit del conocimiento florístico, las subdivisiones biogeográficas dentro del Neotrópico, establecidas con patrones de distribución de plantas superiores, solo en pocos casos son apoyadas por la distribución de líquenes foliícolas.
This further contribution to the knowledge of the foliicolous lichen flora of Costa Rica provides a detailed account on the genus Fellhanera. In total, 25 species and five undescribed taxa are treated. Ten species are described as new: Fellhanera angustispora sp.n., F. dictyospora sp.n., F. dispersa sp.n., F. emarginata sp.n., F. pilomarginata sp.n., F. longispora sp.n., F. muhlei sp.n., F. montana sp.n., F. verrucifera sp.n., and F. viridis sp.n. New combinations are F. pauciseptata (R. Sant.) R. Lücking comb.n. [Bas.: Bacidia pauciseptata R. Sant.] and F. rubida (Müll. Arg.) R. Lücking comb.n. [Bas.: Patellaria rubida Müll. Arg.]. F. dominicana (Vain.) Vezda is placed into synonymy with F. fuscatula (Müll. Arg.) Vezda, whose type has 7-septate ascospores, and the name F. subfuscatula R. Lücking sp.n. is introduced for the taxon with 5-septate ascospores formerly known as F. fuscatula. F. misionensis Ferraro & R. Lücking ined. and F. sublecanorina (Nyl.) Vezda are reported for the first time from Costa Rica. The formerly invalidly published names F. farinosa nom. nud. and F. pilosa nom. nud. are considered to be synonyms of F. fuscatula (Müll. Arg.) Vezda and F. rhapidophylli (Rehm) Vezda, respectively. Specimens identified as F. tuckeri nom. nud. belong to F. rhapidophylli as well. F. buxi is excluded from the foliicolous lichen flora of Costa Rica. A keys is provided to the complex group of species of Fellhanera with brownish apothecia and 3-septate ascospores. Infrageneric relationships within Fellhanera are briefly discussed, and notes on the ecology of the species are provided.
A total of 233 foliicolous lichen species and 18 lichenicolous fungi are reported from Guyana as a result of the Smithsonian „International Cryptogamic Expedition to Guyana“ 1996. Three lichens and two lichenicolous fungi are new to science: Arthonia grubei sp.n., Badimia subelegans sp.n., Calopadia pauciseptata sp.n., Opegrapha matzeri sp.n. (lichenicolous on Amazonomyces sprucei), and Pyrenidium santessonii sp.n. (lichenicolous on Bacidia psychotriae). The new combination Strigula janeirensis (Bas.: Phylloporina janeirensis; syn.: Raciborskiella janeirensis) is proposed. Apart from Amazonomyces sprucei and Bacidia psychotriae, Arthonia lecythidicola (with the lichenicolous A. pseudopegraphina) and Byssolecania deplanata (with the lichenicolous Opegrapha cf. kalbii) are reported as new hosts for lichenicolous fungi. Arthonia pseudopegraphina growing on A. lecythidicola is the first known case of adelphoparasitism at generic level in foliicolous Arthonia. Arthonia flavoverrucosa, Badimia polillensis, and Byssoloma vezdanum are new records for the Neotropics, and 115 species are new for Guyana, resulting in a total of c. 280 genuine foliicolous species reported for that country, while Porina applanata and P. verruculosa are excluded from its flora. The foliicolous lichen flora of Guyana is representative for the Guianas (Guyana, Suriname, French Guiana) and has great affinities with the Amazon region, while the degree of endemism is low. A characteristic species for this area is Amazonomyces sprucei. Species composition is typical of Neotropical lowland to submontane humid forests, with a dominance of the genera Porina, Strigula, and Mazosia. The table mountain vegetation supports elements of the upper montane forest, such as Echinoplaca fusconitida and Logilvia gilva. Foliicolous lichen diversity is highest in undisturbed lowland to submontane humid forest, much lower in the table mountain vegetation and drastically decreased in semi-open secondary vegetation and the coastal savanna. Species composition in semi-open, disturbed vegetation is similar to that found in the undisturbed forest canopy. Site preferences of foliicolous lichens follow those established by studies in other Neotropical regions like Costa Rica.
A model for the description of proton collisions from molecules composed of atoms such as hydrogen, carbon, nitrogen, oxygen and phosphorus (H, C, N, O, P) was recently extended to treat collisions with multiply charged ions with a focus on net ionization. Here we complement the work by focusing on net capture. The ion–atom collisions are computed using the two-center basis generator method. The atomic net capture cross sections are then used to assemble two models for ion–molecule collisions: An independent atom model (IAM) based on the Bragg additivity rule (labeled IAM-AR), and also the so-called pixel-counting method (IAM-PCM) which introduces dependence on the orientation of the molecule during impact. The IAM-PCM leads to significantly reduced capture cross sections relative to IAM-AR at low energies, since it takes into account the overlap of effective atomic cross sectional areas. We compare our results with available experimental and other theoretical data focusing on water vapor (H2O), methane (CH4) and uracil (C4H4N2O2). For the water molecule target we also provide results from a classical-trajectory Monte Carlo approach that includes dynamical screening effects on projectile and target. For small molecules dominated by a many-electron atom, such as carbon in methane or oxygen in water, we find a saturation phenomenon for higher projectile charges (q=3) and low energies, where the net capture cross section for the molecule is dominated by the net cross section for the many-electron atom, and the net capture cross section is not proportional to the total number of valence electrons.
Für Marburg-Hermershausen ließ sich während einer Kartierung im Rahmen der Dorferneuerung 1985 ein qualitativer und quantitativer Rückgang charakteristischer Dorfvegetation feststellen, der durch Versiegelung, Einschränkung landwirtschaftlicher Nutzungen, Verlust traditioneller volkskundlicher Heilmethoden und übertriebenem Sauberkeitsbestreben bedingt ist. Zur Umsetzung der Ergebnisse wurden Vorschläge entwickelt, die sich an die Bevölkerung, Behörden und Planer wenden, wie eine Verbesserung der Dorfökologie für Pflanzen (und Tiere) erreicht werden kann. Allein die Einsicht in die Notwendigkeit zur Erhaltung und Förderung der vom Menschen geprägten Dorfvegetation kann diese so bedrängte Vegetation retten.