Abstracts - Deutsche Zoologische Gesellschaft

Physiology Posters 191and Remipedia. Three distinct hemocyanin subunit types (alpha, beta and gamma) had been identifiedin the Eucarida. However, little has been known on hemocyanin structure and subunit compositionin Hoplocarida and Pericarida. Here we investigate the hemocyanin from the stomatopod Odontodactylusscyllarus (Hoplocarida). Two distinct hemocyanin subunit types have been identified inthe hemolymph by Western blotting. By reverse transcription PCR, hemocyanin cDNA fragmentswere obtained from RNA extracted from the whole body.P PH.10 - ENLocalization and expression analyses of Globin X in zebrafishJessica Wollberg, Frank Gerlach, Thorsten BurmesterBiocenter Grindel and Zoological Museum, University of HamburgGlobins are small respiratory proteins consisting of approximately 150 amino acids and a porphyrinringwith a Fe 2+ ion. In vertebrates, five distinct globin types with different tissue distributions andfunctions have been identified. Hemoglobin and myoglobin are among the best-studied proteins,whereas the physiological roles of neuroglobin and cytoglobin are still uncertain. While these fourglobin types are probably present in all vertebrate taxa, globin X (GbX) appears to be restricted tothe “lower vertebrates” (fish and amphibia). For better understanding of its function, we investigatethe cellular and subcellular localisation of GbX. By Western blotting, we found that the protein ispreferentially present in brain and oocytes. Analyses of GbX sequences revealed two conserved N-terminal lipid modification sites: N-myristoylation followed by S-palmitoylation. The general functionof myristoylation and palmitoylation is to increase the affinity of a soluble protein to cellularmembranes and to stabilize membrane association. Currently, we investigate the possible interactionof GbX with the cell membrane.P PH.11 - ENInsect hemocyanin: expression analysis in cockroachesChristian Pick, Marco Schneuer, Thorsten BurmesterBiocenter Grindel und Zoological Museum, University of HamburgHemocyanins (Hc) are the respiratory proteins that float freely dissolved in the hemolymph of manyarthropod species. Even though well-known in Chelicerata and malacostracan Crustacea their widespreadoccurrence in other arthropods (e.g., insects) has been discovered only recently. Becauseinsects possess a tracheal system, a network of tubules through which O 2is delivered in the gaseousphase, respiratory proteins had been considered unnecessary. A functional Hc, however, is present inthe stonefly Perla marginata and Hc sequences were identified in most other hemimetabolous andametabolous insects. Here we present the full length cDNAs of two distinct subunits from the cockroachesPeriplaneta americana (Blattidae) and Blaptica dubia (Blaberidae). Phylogenetic analysesshow that the subunits are orthologous to subunits 1 and 2 of the stonefly P. marginata. We alsofound the cockroach Hcs to be paraphyletic with respect to the Hcs of the termite Cryptotermes secundus.Expression analyses show that Hc mRNA is present in all developmental stages of B. dubia,whereas the protein was only found in the hemolymph of first instar nymphs. Hence, mRNA mightonly be translated under hypoxia, which is true for first instar nymphs due to their incomplete trachealsystem. This hypothesis of a post-transcriptional hypoxia-induced regulation is also reinforcedby the fact that hypoxia treatment did not alter the expression of Hc mRNA in adult B. dubia.