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.
Das Projekt "Microarrays for the detection of toxic algae (MIDTAL)" wird vom Umweltbundesamt gefördert und von Natural Environment Research Council, Marine Biological Association of the United Kingdom durchgeführt. Objective: Microalgae in marine and brackish waters of Europe regularly cause 'harmful effects', considered from the human perspective, in that they threaten public health and cause economic damage to fisheries and tourism. Cyanobacteria cause similar problems in freshwaters. These episodes encompass a broad range of phenomena collectively referred to as 'harmful algal blooms' (HABs). They include discoloration of waters by mass occurrences of microalgae (true algal blooms that may or may not be 'harmful') to toxin-producing species that may be harmful even in low cell concentrations. A broad classification of HAB distinguishes three groups of toxic organisms. For adequate management of these phenomena, monitoring of microalgae is required. However, the effectiveness of monitoring programmes is limited by the fact that it is time consuming and morphology as determined by light microscopy may be insufficient to give definitive species and toxin attribution. Once cell numbers reach a threshold level, then shellfish are selected to toxin analysis by the mouse bioassay. The mouse bioassay is continued on a daily basis until no more toxin is detected. Molecular and biochemical methods are now available that offer rapid means of both species and toxin detection. In this project we will target rapid species identification using rRNA genes as the target. We include antibodies to specific toxins because even when cell numbers are very low, the toxins can be present and can be accumulated in the shellfish. Microarrays are the state of the art technology in molecular biology for the processing of bulk samples for detection of target RNA/DNA sequences.. The purpose of MIDTAL is to support the common fisheries policy to aid the national monitoring agencies by providing new rapid tools for the identification of toxic algae and their toxins so that they can comply with ECC directive 91/1491/CEE that can be converted to cell numbers and reduce the need for the mouse bioassay.