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Search Results: 1 - 10 of 156 matches for " Maike Forstner "
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A receptor and binding protein interplay in the detection of a distinct pheromone component in the silkmoth Antheraea polyphemus
Maike Forstner, Heinz Breer, Jürgen Krieger
International Journal of Biological Sciences , 2009,
Abstract: Male moths respond to conspecific female-released pheromones with remarkable sensitivity and specificity, due to highly specialized chemosensory neurons in their antennae. In Antheraea silkmoths, three types of sensory neurons have been described, each responsive to one of three pheromone components. Since also three different pheromone binding proteins (PBPs) have been identified, the antenna of Antheraea seems to provide a unique model system for detailed analyzes of the interplay between the various elements underlying pheromone reception. Efforts to identify pheromone receptors of Antheraea polyphemus have led to the identification of a candidate pheromone receptor (ApolOR1). This receptor was found predominantly expressed in male antennae, specifically in neurons located beneath pheromone-sensitive sensilla trichodea. The ApolOR1-expressing cells were found to be surrounded by supporting cells co-expressing all three ApolPBPs. The response spectrum of ApolOR1 was assessed by means of calcium imaging using HEK293-cells stably expressing the receptor. It was found that at nanomolar concentrations ApolOR1-cells responded to all three pheromones when the compounds were solubilized by DMSO and also when DMSO was substituted by one of the three PBPs. However, at picomolar concentrations, cells responded only in the presence of the subtype ApolPBP2 and the pheromone (E,Z)-6,11-hexadecadienal. These results are indicative of a specific interplay of a distinct pheromone component with an appropriate binding protein and its related receptor subtype, which may be considered as basis for the remarkable sensitivity and specificity of the pheromone detection system.
Antennal expression pattern of two olfactory receptors and an odorant binding protein implicated in host odor detection by the malaria vector Anopheles gambiae
Danuta Schymura, Maike Forstner, Anna Schultze, Thomas Kr?ber, Luc Swevers, Kostas Iatrou, Jürgen Krieger
International Journal of Biological Sciences , 2010,
Abstract: Odor-detection in the malaria mosquito Anopheles gambiae involves large families of diverse proteins, including multiple odorant binding proteins (AgOBPs) and olfactory receptors (AgORs). The receptors AgOR1 and AgOR2, as well as the binding protein AgOBP1, have been implicated in the recognition of human host odors. In this study, we have explored the expression of these olfactory proteins, as well as the ubiquitous odorant receptor heteromerization partner AgOR7, in the thirteen flagellomeres (segments) of female and male antenna. Expressing cells were visualized by adapting a whole mount fluorescence in situ hybridization method. In female mosquitoes, AgOR1-expressing olfactory receptor neurons (ORNs) were almost exclusively segregated in segments 3 to 9, whereas AgOR2-expressing ORNs were distributed over flagellomeres 2 to 13. Different individuals comprised a similar number of cells expressing a distinct AgOR type, although their antennal topography and number per flagellomere varied. AgOBP1-expressing support cells were present in segments 3 to 13 of the female antenna, with increasing numbers towards the distal end. In male mosquitoes, total numbers of AgOR- and AgOBP1-expressing cells were much lower. While AgOR2-expressing cells were found on both terminal flagellomeres, AgOR1 cells were restricted to the most distal segment. High densities of AgOBP1-expressing cells were identified in segment 13, whereas segment 12 comprised very few. Altogether, the results demonstrate that both sexes express the two olfactory receptor types as well as the binding protein AgOBP1 but there is a significant sexual dimorphism concerning the number and distribution of these cells. This may suggest gender-specific differences in the ability to detect distinct odorants, specifically human host-derived volatiles.
Sex-Specific Odorant Receptors of the Tobacco Hornworm Manduca Sexta
Ewald Gro?e-Wilde,Regina Stieber,Maike Forstner,Jürgen Krieger,Dieter Wicher,Bill S. Hansson
Frontiers in Cellular Neuroscience , 2010, DOI: 10.3389/fncel.2010.00022
Abstract: As odor information plays a vital role in the life of moths, their olfactory sense has evolved into a highly specific and sensitive apparatus relevant to reproduction and survival. The key players in the detection of odorants are olfactory receptor (OR) proteins. Here we identify four OR-encoding genes differentially expressed in the antennae of males and females of the sphingid moth Manduca sexta. Two male-specific receptors (the previously reported MsexOR-1 and the newly identified MsexOR-4) show great resemblance to other male moth pheromone ORs. The putative pheromone receptors are co-expressed with the co-receptor involved in general odorant signal transduction, the DmelOr83b homolog MsexOR-2. One female-specific receptor (MsexOR-5) displays similarities to BmorOR-19, a receptor in Bombyx mori tuned to the detection of the plant odor linalool.
The Making of a Genius: Richard P. Feynman
Christian Forstner
Physics , 2012,
Abstract: In 1965 the Nobel Foundation honored Sin-Itiro Tomonaga, Julian Schwinger, and Richard Feynman for their fundamental work in quantum electrodynamics and the consequences for the physics of elementary particles. In contrast to both of his colleagues only Richard Feynman appeared as a genius before the public. In his autobiographies he managed to connect his behavior, which contradicted several social and scientific norms, with the American myth of the "practical man". This connection led to the image of a common American with extraordinary scientific abilities and contributed extensively to enhance the image of Feynman as genius in the public opinion. Is this image resulting from Feynman's autobiographies in accordance with historical facts? This question is the starting point for a deeper historical analysis that tries to put Feynman and his actions back into historical context. The image of a "genius" appears then as a construct resulting from the public reception of brilliant scientific research.
Polymer Supported Lipid Bilayers  [PDF]
Ian P. McCabe, Martin B. Forstner
Open Journal of Biophysics (OJBIPHY) , 2013, DOI: 10.4236/ojbiphy.2013.31A008

Lipid bilayers are some of the most fascinating self-assembled structure in living nature. Not only do they serve as the protective boundary of cells and their internal organelles, they also organize and host major parts of the biochemical machinery for cellular communication and transmembrane transport. To study aspects of cellular membranes in a controlled manner, solid supported planar bilayers have served as reliable tools for many decades. They have been used in a large variety of studies ranging from fundamental investigations of membranes and their constituents to the dissection of cellular signaling mechanisms. However, there are limitations to these systems and recently a class of new systems in which the lipid bilayer is supported on a soft, polymer cushion has emerged. Here, we review the different polymer cushioned bilayer systems and discuss their manufacture and advantages.

(Online-)Beratung soziotechnisch betrachtet
Maike Hecht
E-Beratungsjournal , 2010,
Abstract: Online-Beratung hat sich in der vergangenen Dekade von einem exotischen zu einem weitgehend anerkannten Angebot vieler Beratungsstellen gewandelt. Im Zuge dieser Institutionalisierung wurden Anwendungsgebiete, Qualit ts- und Kompetenzanforderungen intensiv diskutiert, was in der Etablierung erster Standards und Ausbildungsprofile mündete. Im Gegensatz dazu hat sich die eingesetzte Technik und ihre Gestaltung in den vergangenen zehn Jahren nur wenig ver ndert – wenngleich gerade das Internet als ein hochdynamisches Medium gilt, das sowohl auf der technischen als auch auf Seiten der Nutzungsgewohnheiten in dieser Zeit durchaus einen Ver nderungsprozess durchgemacht hat. Dieser Artikel betrachtet Online-Beratung aus einer Entwicklerperspektive und lenkt den Blick auf Alternativen zur derzeitigen starken Orientierung an den etablierten Tools E-Mail, Chat und Foren. Er schl gt eine ausführliche soziotechnische Anforderungsanalyse vor, die eine genaue Erhebung der Bedarfe des sozialen Systems ebenso enth lt wie eine detaillierte Auseinandersetzung mit den besonderen Eigenschaften des Mediums Internet und ihrer m glichen Nutzung in der und für die Beratungsarbeit.
An unsupervised classification scheme for improving predictions of prokaryotic TIS
Maike Tech, Peter Meinicke
BMC Bioinformatics , 2006, DOI: 10.1186/1471-2105-7-121
Abstract: We introduce a clustering algorithm for completely unsupervised scoring of potential TIS, based on positionally smoothed probability matrices. The algorithm requires an initial gene prediction and the genomic sequence of the organism to perform the reannotation. As compared with other methods for improving predictions of gene starts in bacterial genomes, our approach is not based on any specific assumptions about prokaryotic TIS. Despite the generality of the underlying algorithm, the prediction rate of our method is competitive on experimentally verified test data from E. coli and B. subtilis. Regarding genomes with high G+C content, in contrast to some previously proposed methods, our algorithm also provides good performance on P. aeruginosa, B. pseudomallei and R. solanacearum.On reliable test data we showed that our method provides good results in post-processing the predictions of the widely-used program GLIMMER. The underlying clustering algorithm is robust with respect to variations in the initial TIS annotation and does not require specific assumptions about prokaryotic gene starts. These features are particularly useful on genomes with high G+C content. The algorithm has been implemented in the tool ?TICO?(TIs COrrector) which is publicly available from our web site.Recent publications have shown that gene prediction in prokaryotes is still a challenging problem in bioinformatics. While existing gene finders [1-3] are likely to identify coding regions associated with open reading frames (ORF) of statistically significant length, the prediction of the true translation initiation sites (TIS) is insufficient in many cases [4-6]. In particular, for genomes with a high G+C content the prediction of TIS has been shown to be of low quality [6].In order to cope with this insufficiency of conventional gene finders, several methods have been proposed for improving the predictions of prokaryotic TIS. Common approaches require prior knowledge about the characteristics
Hoffen auf den guten Willen – von der unverbindlichen Institutionalisierung feministischer Forderungen Hoping for Good Will—On the Non-Binding Institutionalization of Feminist Demands
Maike Bu?mann
querelles-net , 2008,
Abstract: Nachdem die Protagonistinnen der ersten Frauenbewegung prinzipiell den Zugang in die Institutionen erstritten hatten, wurde seit den 1968ern der Marsch durch die Institutionen angetreten. Diesen untersucht Stefanie Ehmsen für die Vereinigten Staaten und die Bundesrepublik, wobei sie die Unterschiede als Resultat der jeweiligen politischen Traditionen interpretiert. Zwar wartet sie mit gut recherchierten und lesenswerten Fallbeispielen auf, doch das Potential der Analyse wird leider nicht ausgesch pft. After the protagonists of the first women’s movement managed to win entrance into the institutions, at least in principle, since 1968 the march through the institutions has been underway. Stefanie Ehmsen examines this fact in the United States and in the Federal Republic, however she interprets the differences to be the result of the respective political traditions. Although she provides well-researched case studies that are worth reading, she unfortunately does not exhaust the potential of the analysis.
Yang-Mills Solutions and Dyons on Cylinders over Coset Spaces with Sasakian Structure
Maike Torm?hlen
Physics , 2014, DOI: 10.1016/j.nuclphysb.2015.11.013
Abstract: We present solutions of the Yang-Mills equation on cylinders $\mathbb R\times G/H$ over coset spaces with Sasakian structure and odd dimension $2m+1$. The gauge potential is assumed to be $SU(m)$-equivariant, parametrized by two real, scalar-valued functions. Yang-Mills theory with torsion in this setup reduces to the Newtonian mechanics of a point particle moving in $\mathbb R^2$ under the influence of an inverted potential. We analyze the critical points of this potential and present an analytic as well as several numerical finite-action solutions. Apart from the Yang-Mills solutions that constitute $SU(m)$-equivariant instanton configurations, we construct periodic sphaleron solutions on $S^1\times G/H$ and dyon solutions on $i\mathbb R\times G/H$.
Tame Class Field Theory for Global Function Fields
Florian Hess,Maike Massierer
Mathematics , 2013,
Abstract: We give a function field specific, algebraic proof of the main results of class field theory for abelian extensions of degree coprime to the characteristic. By adapting some methods known for number fields and combining them in a new way, we obtain a different and much simplified proof, which builds directly on a standard basic knowledge of the theory of function fields. Our methods are explicit and constructive and thus relevant for algorithmic applications. We use generalized forms of the Tate-Lichtenbaum and Ate pairings, which are well-known in cryptography, as an important tool.
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