Das Projekt "Expressed Sequence Tags (ESTS) of Toxic Algae (ESTTAL)" wird vom Umweltbundesamt gefördert und von Stiftung Alfred-Wegener-Institut für Polar- und Meeresforschung e.V. in der Helmholtz-Gemeinschaft (AWI) durchgeführt. Harmful algal blooms (HABs) are caused by local proliferation of algae, with deleterious consequences, particularly in coastal waters throughout the world. Negative environmental effects include toxicity to human consumers of seafood, marine faunal mortalities or morbidity, habitat damage, disruption of marine food webs and economic losses to fishing, aquaculture, and tourism. In Europe, socio-economic factors and human health risk have led to comprehensive surveillance programmes for harmful microalgae and their toxins. Among harmful microalgae and cyanobacteria in European marine and brackish waters, many produce potent neurotoxins, ichthyotoxins or hepatotoxins. Although structural elucidation of many of these groups of toxins has advanced, much less is known about biosynthetic pathways and gene regulation in toxigenic species. We propose a limited genomic study of expressed sequence tags (ESTs) for toxigenic representatives of major eukaryotic microalgal groups, including dinoflagellates, raphidophytes, prymnesiophytes and diatoms, and cyanobacteria. Cultures will be grown under various environmental conditions to investigate the effects of external forcing functions on gene expression linked to toxicity and growth. After cloning of cDNA of toxigenic strains pooled from cultures grown under these different conditions into plasmid vectors, about 10,000 clones from each taxon will be randomly sequenced for ESTs. Our approach is to annotate the ESTs and attempt to identify genes associated with toxin production. DNA microarrays will be developed for screening of toxigenic and non-toxigenic strains. In addition, the sequence data will be analysed to identify other genes that may be involved in cell regulation or growth, cell cycle events, stress response and the induction of sexuality. Cultures will be grown under various environmental conditions to investigate the effects of external forcing functions on gene expression linked to toxicity and growth. Successful completion of this project will yield new information on microalgal and cyanobacterial genomic sequences for a diversity of taxa and will assist in the diagnosis of genes related to toxin biosynthesis and the formation of toxic blooms.
For the evaluation of effects of hormone-active substances to fish, several test guidelines have been validated by the OECD which are included in the Conceptual Framework for Testing and Assessment of Endocrine Disruptors (OECD, 2010). In these tests, the assessment of physiological parameters is limited to the established biomarkers like vitellogenin or 11-keto testosterone in blood plasma or liver tissue. A promising approach<BR>to refine existing testing strategies is the integration of molecular endpoints, which rapidly respond to exposure. Furthermore, these endpoints can be indicative of potential adverse effects at the organismal level by providing information, which connect to the initiating effect of a substance. This is in line with the concept of Adverse Outcome Pathways (AOP), which evolved from the "toxicity pathwayŁ approach as a mechanistic evaluation tool for the risk assessment.<BR>Quelle: https://www.umweltbundesamt.de/