Abstracts - Deutsche Zoologische Gesellschaft

18 Key Lectures of the Symposiaphorans, and annelids suggests that this is indeed the case. For example, a well-developed mushroombody, comprising many thousand small diameter globuli (Kenyon) cells is present in arthropods aswell as in annelids, two groups that represent distantly related protostome clades. We will discuss theconsequences for our understanding of metazoan brain evolution for both possible scenarios, first,the one that assumes that similar brain structures arose only once during evolution and second, theopposite view that structures like the mushroom bodies might have evolved independently. (DFGgrant Lo 797/3-2)S NB.2 (Mo) - ENIn vivo visualization of odor coding and processing in the Drosophila brainSilke Sachse, Marco Schubert, Sonja Bisch-Knaden, , Bill S. HanssonDepartment of Evolutionary Neuroethology, Max Planck Institute for Chemical Ecology, JenaMost organisms rely on their olfactory system to detect and analyze chemical cues in the environment,cues which are subsequently utilized in the context of behavior. The basic layout of the firstolfactory processing centers, the olfactory bulb in vertebrates and the antennal lobe in insects, is remarkablysimilar. Odors are encoded by specific ensembles of activated glomeruli (the structural andfunctional units of the bulb-lobe) in a combinatorial manner. However, a comparison of the transformationof odor representations between input to the antennal lobe and output to higher brain centersyields a complex and contradictory picture. The question of how odors are processed is accordinglyopen. A central problem regarding our present understanding of olfactory processing is that virtuallynothing is known regarding the inhibitory components. The inhibitory processes are assumedto be as important as the well-studied excitatory pathways, however, the necessary tools to studythe former processes in imaging studies have so far been lacking. In order to visualize inhibitoryresponses, we used a newly described fluorescent protein, named Clomeleon, which functions as anindicator for chloride ions — the main mediator of synaptic inhibitions in mature neurons. Usingthe standard GAL4-UAS system in Drosophila melanogaster, we genetically expressed Clomeleonin subpopulations of olfactory neurons to measure and characterize neuronal inhibitions at differentprocessing levels in the Drosophila olfactory system.S PH.1 (Sa) - ENInsights into evolutionary ecology of insect immunityBoran AltincicekJustus-Liebig-Universität, GießenThe evolutionary success of insects regarding diversity in species and ecological niches reflectstheir prominent ability to control a wide array of pathogens. Here, we have identified immune-induciblegenes in phylogenetically distant insects using subtractive suppression hybridization. Resultsfrom the apterygote Thermobia domestica, the aphid Acyrthosiphon pisum, the drone fly Eristalistenax, and the genetically tractable model beetle Tribolium castaneum revealed the immune inducedexpression of genes encoding proteins involved in signaling, defense mechanisms, stress response,and cellular homeostasis. However, we also noted differences, especially on antimicrobial peptides(AMPs). We identified thaumatins in Tribolium (ancient antifungal plant peptides) that are absentfrom most other insects and numerous putative E. tenax specific AMPs. In the aphid we havefound lysozyme activity but no detectable inhibitory activities against live bacteria. We identified