Projekte

Alterung in einzelligen Eukaryoten

Einzellige Eukaryoten mit einem asymmetrischen Zellteilungsmechanismus stellen wertvolle Werkzeuge zur Erforschung von Mechanismen und Modulatoren der replikativen und chronologischen Zellalterung dar. In einer kollaborativen Forschungsinitiative der beteiligten Fachgebiete werden Schlüsselmodulatoren der Zellalterung hinsichtlich möglicher funktioneller Konservierung zwischen den entfernt verwandten Gruppen der Diatomeen (als Vertreter der Stramenopiles) und der Hefen (als Vertreter der Fungi) untersucht.

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UNCD-basierte Oberflächen zur Untersuchung von zeitaufgelösten neuronalen Signalen

Due to the outstanding electrochemical properties, superior chemical inertness and biocompatibility, etc., diamond in a form of thin films with different crystallinities has been recognized as an extremely attractive material for (bio-)chemical sensing and as an interface to biological systems. The ultrananocrystalline diamond (UNCD) films deposited in our group by microwave plasma chemical vapor deposition from methane/nitrogen gas mixtures are composed of diamond nanocrystallites of up to 10 nm diameter embedded in an amorphous carbon matrix. Their surface is smooth with rms roughness of 10 – 14 nm and H-terminated, rounded nanostructures with diameters up to 100 nm dominate the topography. After surface modifications by different plasma and photochemical processes the UNCD surface can be rendered strongly hydrophilic (with O- or NH2-termination) or strongly hydrophobic (with F-termination). Furthermore, the surface termination can be patterned.

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Zeitliche Steuerung des Fettstoffwechsels in Dictyostelium

In der einzelligen Amöbe Dictyostelium, wie auch in anderen einzelligen Eukaryonten und vielen Bakterien, führt Nahrungsmangel zu einer Abfolge von Entwicklungsschritten an deren Ende die Bildung von Sporen steht. Diese Überdauerungsstadien sind resistent gegen Hitze, Kälte, Trockenheit und natürlich auch Nahrungsmangel. Eigentlich sollten es intrazelluläre Nahrungsreserven den Zellen ermöglichen Hungerphasen zu überstehen, aber überraschenderweise verhindert gespeichertes Fett, dass sich die Zellen zu Sporen entwickeln. Innerhalb des Graduiertenkollegs “Biologische Uhren” werden wir untersuchen, zu welchem Zeitpunkt die Zelle entscheidet eine Spore zu werden, oder daran zu scheitern.

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Localization and interaction of PDF neuropeptides in Onychophora and Tardigrada

Although numerous studies have been performed on pigment-dispersing factor neuropeptides (PDFs) in arthropods – a neuropeptide, which acts as a circadian neuromodulator – only little is known about the expression and interaction of PDFs with their receptors in the closest relatives of arthropods, the onychophorans (velvet worms) and tardigrades (water bears). The aim of our project is therefore to localize the two identified PDF neuropeptides in onychophorans and the three PDFs in tardigrades together with their respective receptors using immunolabelling with specific antibodies.

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The role of Orco in hawkmoth pheromone transduction and in the control of circadian changes in olfactory sensitivity

Insect odor transduction is still not resolved, despite the fact that its understanding is a crucial prerequisite to controlling the behaviour of pest, vector, or beneficial insects. Odours from the environment and pheromones (species-specific odours) can be detected via odour receptor neurons (ORNs) on insect antennae. It is well known that insect olfactory receptors (ORs) expressed in ORNs consist of a highly conserved olfactory receptor co-receptor (Orco) subunit and a highly variable ligand-binding OR subunit. Orco locates and maintains ORs in ciliary membranes as prerequisite to odor responses (termed chaperone function). Despite several excellent investigations, it remains unclear how Orco and OR proteins interact with each other during odor transduction. 

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Morphological and functional examination of neuropeptides in the circadian system of Rhyparobia maderae with focus on myoinhibitory peptides

The cockroach Rhyparobia maderae is an established model organism for circadian research. Transplantation experiments located the circadian clock that controls rest-activity cycles to the accessory medulla (AME) with innervating pigment-dispersing factor (PDF) expressing neurons. The AME is a small optic lobe neuropil innervated by about 240 neurons belonging to 8 soma groups that are enriched in neuropeptides. Among all AME clock neurons the 12 anterior PDF expressing cells are studied best. Two of them co-express myoinhibitory peptides (MIPs). We want to understand the function of MIP in the circadian system of the cockroach.

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Functional characterization of circadian clock neuronal circuits controlling sleep-wake rhythms in the Madeira cockroach Rhyparobia maderae

The Madeira cockroach Rhyparobia maderae is an established model system in chronobiology, especially suited to cellular, electrophysiological, biochemical and behavioural analysis due to its large size and long lifespan. In the Madeira cockroach the accessory medulla (AME) with adjacent pigment-dispersing factor (PDF)-expressing neurons is the circadian pacemaker centre that controls sleep-wake rhythms. Previous studies found that circadian clock neurons that project to the contralateral circadian clock control locomotor activity rhythms (reviews: Stengl et al. 2015, Current Opinion in Insect Science; Stengl & Arendt 2016, Current Opinion in Neurobiology). Thus, we distinguished contralaterally projecting from ipsilaterally remaining circadian clock neurons via backfills from the contralateral AME (Gestrich et al. 2018, Journal of Biological Rhythms).

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