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G protein-coupled receptor (GPCR) genes are large gene families in every animal, sometimes making up to 1-2% of the animal's genome. Of all insect GPCRs, the neurohormone (neuropeptide, protein hormone, biogenic amine) GPCRs are especially important, because they, together with their ligands, occupy a high hierarchic position in the physiology of insects and steer crucial processes such as development, reproduction, and behavior. In this paper, we give a review of our current knowledge on Drosophila melanogaster GPCRs and use this information to annotate the neurohormone GPCR genes present in the recently sequenced genome from the honey bee Apis mellifera. We found 35 neuropeptide receptor genes in the honey bee (44 in Drosophila) and two genes, coding for leucine-rich repeats-containing protein hormone GPCRs (4 in Drosophila). In addition, the honey bee has 19 biogenic amine receptor genes (21 in Drosophila). The larger numbers of neurohormone receptors in Drosophila are probably due to gene duplications that occurred during recent evolution of the fly. Our analyses also yielded the likely ligands for 40 of the 56 honey bee neurohormone GPCRs identified in this study. In addition, we made some interesting observations on neurohormone GPCR evolution and the evolution and co-evolution of their ligands. For neuropeptide and protein hormone GPCRs, there appears to be a general co-evolution between receptors and their ligands. This is in contrast to biogenic amine GPCRs, where evolutionarily unrelated GPCRs often bind to the same biogenic amine, suggesting frequent ligand exchanges ("ligand hops") during GPCR evolution. (c) 2006 Elsevier Ltd. All rights reserved.
In Allefeld & Kurths [2004], we introduced an approach to multivariate phase synchronization analysis in the form of a Synchronization Cluster Analysis (SCA). A statistical model of a synchronization cluster was described, and an abbreviated instruction on how to apply this model to empirical data was given, while an implementation of the corresponding algorithm was (and is) available from the authors. In this letter, the complete details on how the data analysis algorithm is to be derived from the model are filled in.
The biogenic amine serotonin (5-HT) plays a key role in the regulation and modulation of many physiological and behavioural processes in both vertebrates and invertebrates. These functions are mediated through the binding of serotonin to its receptors, of which 13 subtypes have been characterized in vertebrates. We have isolated a cDNA from the honeybee Apis mellifera (Am5-ht7) sharing high similarity to members of the 5-HT7 receptor family. Expression of the Am5-HT7 receptor in HEK293 cells results in an increase in basal cAMP levels, suggesting that Am5-HT7 is expressed as a constitutively active receptor. Serotonin application to Am5-ht7-transfected cells elevates cyclic adenosine 3',5'-monophosphate (cAMP) levels in a dose-dependent manner (EC50 = 1.1-1.8 nM). The Am5-HT7 receptor is also activated by 5-carboxamidotryptamine, whereas methiothepin acts as an inverse agonist. Receptor expression has been investigated by RT-PCR, in situ hybridization, and western blotting experiments. Receptor mRNA is expressed in the perikarya of various brain neuropils, including intrinsic mushroom body neurons, and in peripheral organs. This study marks the first comprehensive characterization of a serotonin receptor in the honeybee and should facilitate further analysis of the role(s) of the receptor in mediating the various central and peripheral effects of 5-HT.
Biogenic amines are important messenger substances in the central nervous system and in peripheral organs of vertebrates and of invertebrates. The honeybee, Apis mellifera, is excellently suited to uncover the functions of biogenic amines in behaviour, because it has an extensive behavioural repertoire, with a number of biogenic amine receptors characterised in this insect. In the honeybee, the biogenic amines dopamine, octopamine, serotonin and tyramine modulate neuronal functions in various ways. Dopamine and serotonin are present in high concentrations in the bee brain, whereas octopamine and tyramine are less abundant. Octopamine is a key molecule for the control of honeybee behaviour. It generally has an arousing effect and leads to higher sensitivity for sensory inputs, better learning performance and increased foraging behaviour. Tyramine has been suggested to act antagonistically to octopamine, but only few experimental data are available for this amine. Dopamine and serotonin often have antagonistic or inhibitory effects as compared to octopamine. Biogenic amines bind to membrane receptors that primarily belong to the large gene-family of GTP-binding (G) protein coupled receptors. Receptor activation leads to transient changes in concentrations of intracellular second messengers such as cAMP, IP3 and/or Ca2+. Although several biogenic amine receptors from the honeybee have been cloned and characterised more recently, many genes still remain to be identified. The availability of the completely sequenced genome of Apis mellifera will contribute substantially to closing this gap. In this review, we will discuss the present knowledge on how biogenic amines and their receptor-mediated cellular responses modulate different behaviours of honeybees including learning processes and division of labour.
Anreizanalyse intensiver Freizeitnutzung von Computern : Hacker, Cracker und zweckorientierte Nutzer
(2006)
Was bringt intensive Computernutzer dazu, ihre Freizeit am Rechner zu verbringen, und gibt es hierbei Unterschiede zwischen verschiedenen Nutzertypen? N = 271 Personen nahmen an einer online Befragung zu Anreizen freizeitlicher Computernutzung teil. Durch ausgewählte Internetverteiler waren gezielt besonders engagierte Computernutzer angesprochen worden (M = 3,9 Freizeitstunden am Rechner pro Tag). Für diese Nutzer fanden sich (in der Reihenfolge ihres Gewichtes) folgende Anreizfaktoren: Zugehörigkeit/Gemeinschaft; Kompetenzerleben; Vielseitigkeit/Nutzen; Langeweilevermeidung; rebellische Illegalitätstendenz. Gruppiert nach ihren bevorzugten Nutzungsweisen fanden sich drei Nutzertypen: Zweckorientierte Nutzer (58%), Hacker (= Eindringen in fremde Systeme ohne Schädigungsabsicht, 22%) und Cracker (Eindringen mit Schädigungsabsicht, 20%). Diese Nutzertypen unterschieden sich deutlich in ihrem Anreizprofil. Hacking und Cracking, nicht aber zweckorientierte Nutzungsweisen waren korreliert mit Flow-Erleben und positiver Aktivierung am Rechner. Die Ergebnisse sind nicht repräsentativ für alle Freizeitnutzer. Sie beziehen sich auf eine gezielt rekrutierte Stichprobe besonders engagierter Computernutzer, die über spezifische Netzwerke (z. B. relevante Fachschaften, Chaos Computer Club) erreichbar sind.
Aus Warschauer Perspektive
(2006)
1455a 32-34 heißt es in der „Poetik“ des Aristoteles, dass die Dichter entweder begabt oder von einem göttlichen Wahnsinn (furor poeticus) besessen seien. Damit scheint es sich bei diesem Satz um die einzige Stelle zu handeln, an der Aristoteles eine göttliche Entrückung der Dichter in Betracht zieht. Die Kommentatoren des 16. Jahrhunderts haben deshalb viel philologischen Scharfsinn auf den Versuch verwendet, diese Stelle so zu deuten, dass sie zur Konzeption der Dichtung als einer technischen Fähigkeit, wie sie die „Poetik“ entwickelt, nicht in Widerspruch steht. Mehr oder weniger explizit wenden sie sich dabei gegen die neuplatonische Enthusiasmus-Theorie Marsilio Ficinos.
Mit diesem Heft wird die Diskussion über eine neue deutsche Ostpolitik fortgesetzt und abgeschlossen. Diese hatte im Heft Nr. 49 mit Thesen von Jochen Franzke begonnen, im nächsten Heft wurden erste Beiträge publiziert. Insgesamt haben sich Wissenschaftler und Politiker aus Deutschland, Österreich, Polen, Finnland und Tschechien beteiligt. Die Debatte schließt mit Schlussbemerkungen des Initiators. Ulrich Best, Katrin Böttger, Vladimir Handl, Heinz Timmermann, Christian Wipperfürth, Sabina Wölkner, Gesine Schwan, Dieter Segert, Beata Wilga, Markus Löning und Ole Diehl, Angelica Schwall-Düren, Wolfgang Gehrcke und Jochen Franzke