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| Development and Evolution of the Aminals Stefan Berking |
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| Developmental Biochemistry and Morphogenetics |
| K.Herrmann U. Hoffmann B.Siefker |
| The main point of interest focuses on the biochemical basis of the control of pattern formation during normal development, metamorphosis and regeneration. Especially interesting are inter- and intracellular signalling molecules of low molecular weight including neurotransmitters. Embryological, cellbiological and biochemical methods (HPLC and mass spectroscopy) are used in the different projects . We are mainly working with coelenterates (cnidaria) of various taxa; in Hydra, some mutants are the objects of our research. By comparison of the obtained results we are expecting to gain an insight into the basic mechanisms of the control of pattern formation and into the evolution of these processes. |
| Sonderforschungsbereich
(SFB 572) "Festlegung von Zellverbänden und Zelltypspezifizierung" Segments in Aurelia aurita A typical cnidarian undergoes two metamorphoses. First of all, it develops from a free swimming larva into a sessile polyp and then, from a sessile polyp into a free swimming medusa. A medusa, the adult stage of Aurelia aurita, is structured similar to a polyp but possesses highly developed sense organs. Funded by the Sonderforschungsbereich we plan to investigate metamorphosis from polyp to medusa, the so called strobilation. Several medusae are formed by one polyp of Aurelia aurita. The formation of medusae begins with the repatterning of the polyp's head and progresses basally. Tissue rings develop into young medusae and detach successively. The process of strobilation is similar to segmentation in bilaterians, a process which has been well studied in arthropods and vertebrates. For example, in annelid worms the formation of segments marks the progression from the larval to the adult stage. Our aim is to investigate whether the similarities of segmentation in bilatarians and cnidarians are only of a superficial kind or share a common basis. |
| Molecular Mechanisms of Development |
| U. Hoffmann B.Siefker Signal molecules play a decisive role in the control of developmental processes. The linkage of signal molecules to receptors activates a signal cascade of which the action is mediated through the phosphorylation of resultant substrates. The earliest molecular answer is the alteration in the transcription rate of so called early or immediate response genes. We are interested in the isolation and characterization of the molecular components of signal cascades which have a function in different developmental stages in cnidaria. Especially early response genes (ERG) are dealt with, which offer access to the isolation of signal molecules as a further issue. |
| Embryopharmacology / Toxikology |
| K.Herrmann |
| The influence of
chemicals on the embryogenesis and pattern formation is analysed. The
aim is to deduce the toxic properties of a molecule from its
structure (QSAR): Furthermore it is important, whether certain
classes of substances act specifically on distinct organs. The
cnidarian Hydractinia echinata
and the fish
Brachydanio rerio are used for the experiments. . |
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