12th International Conference on Harmful Algae

INTERNATIONAL SOCIETY FOR THE STUDY OF HARMFUL ALGAE12 th <strong>International</strong> <strong>Conference</strong> on Harmful Algae, Copenhagen, Denmark, 4-8 September 2006microarray was used to assessglobal transcript profiles under avariety of acute (heat shock,peroxide, lead, NaNO2, andparaquot) and chronic stress (N orP depletion, dark, and cellsenescence). We identified a suiteof genes up-regulated under allconditions that result in decreasedviability and another suiteconsistently down-regulated. Upregulatedgenes include membersof the ubiquitin pathway,senescence-associated cysproteases, and calpains. Genesinvolved in translation andphotosynthesis are consistentlydown-regulated. Components ofthe programmed cell death pathwayare present (metacaspase, caspaserecruitment domain proteins, deathassociatedkinase), but do notrespond at the transcriptional level.The expression of this gene set iscurrently under investigation in fieldpopulations of K. brevis of knowngrowth/stress status to assess theirpotential for biomarkers of bloomtermination.O.17-04A genomic approach towards abetter understanding of domoicacid production in the marinediatom Pseudo-nitzschiamultistriataSession: O.17 - GenomicsPresentation time: 10:10 - 10:30A Luedeking 1 , W Kooistra 1 , MMontresor 1 , D D'Alelio 1 , U John 21 Stazione Zoologica di Napoli, NAPLES,Italy2 Alfred Wegener Institute,BREMERHAVEN, GermanyWithin the diatoms the genusPseudo-nitzschia has gained livelyinterest since 1987 when P.multiseries caused an AmnesicShellfish Poisoning (ASP) eventalong Prince Edward Island,Canada. Production of domoic acidseems to be tightly controlled by thediatom and several enzymes thatmight be involved in the metabolicpathway were recently suggested.Nevertheless, the key enzymesystem facilitating the fusion andtransformation of the two putativeprecursors geranylpyrophosphateand 3-Hydroxy-glutamic acid stillremain unknown. In a first step wedetermined the physiological limitsof P. multistriata to temperature,salinity and nutrient limitation.Thereafter, we investigate toxinproduction under thosephysiological conditions thatstimulate production of domoic acid.In parallel gene expression ofapprox. 4500 genes is measured.Therefore, we use a microarray thatis based on the EST-sequencing ofa normalised cDNA library of P.multistriata. This approach enablesus to make an in silico subtraction ofexpressed genes in relation to toxinproduction resulting in a set ofcandidate genes putatively involvedin toxin synthesis.O.18-01Inter-annual variability ofAlexandrium blooms in CorkHarbour, IrelandSession: O.18 - Ecology & Oceanography 1Presentation time: 09:10 - 09:30A Ní Rathaille, N Touzet, R RaineMartin Ryan Institute, GALWAY, IrelandBlooms of Alexandrium are arecurring problem in the retentiveNorth Channel of Cork Harbour onthe south coast of Ireland. Annualvariations of these blooms includethe timing of their initiation, theirintensity and their duration. Theycan often lead to toxic events andshellfish closures in the North69