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 2006SAGE) we have examinedtranscriptional patterns in threeAureococcus anophagefferenslibraries, nutrient-replete,phosphorus-starved (-P), andnitrogen-starved (-N), designed toidentify nutrient stress responses.Long-SAGE examines geneexpression patterns without a prioriknowledge of gene sequences viathe detection of 21bp sequencetags. To date we have sampledover 75,000 A. anophagefferenssequence tags. Ongoing analysessuggest that A. anophagefferenshas a strong transcriptionalresponse to nutrient starvation, with71 sequence tags significantly(R=2) up-regulated in the –N library,and 179 sequence tags (R=2) upregulatedin the –P library. Unlikethe genome, which is essentiallystatic, these patterns of geneexpression are modulated by thenutritional physiology of the cell andthe ongoing annotation of thesesequence tags will provide adynamic link between A.anophagefferens and its cellularfunctioning in coastal systems.O.17-02EST-based gene discovery andexpression analysis inAlexandrium.Session: O.17 - GenomicsPresentation time: 09:30 - 09:50JD Hackett, DM AndersonWoods Hole Oceanographic Institution,WOODS HOLE, United States of AmericaExpressed sequence tag (EST)-based approaches are an importanttool for facilitating gene discoveryfor organisms without a completegenome sequence. We used ahighly efficient strategy usingnormalized and subtracted cDNAlibraries to generate ESTs for thetoxic dinoflagellate Alexandriumtamarense (9,000 unique ESTs).We are now using these data todetermine the metabolic capabilitiesof Alexandrium. The ESTs wereanalyzed to determine the metabolicpathways present in Alexandriumand to identify genes that may beinvolved in saxitoxin synthesis. Weare also using quantitative-PCR toanalyze gene expression undernitrogen and phosphorus limitationusing cultured strains. Genes thatshow regulation under thesenutrient stress conditions are testedon samples collected from a naturaltoxic bloom of Alexandrium. Theobjective of this work is to design agene expression 'tool kit' that can beused to determine the expression ofgenes involved in nutrient utilizationfrom natural Alexandrium blooms.O.17-03Identification of cellular stressand death-associated genes inKarenia brevis as potentialbiomarkers for bloom terminationSession: O.17 - GenomicsPresentation time: 09:50 - 10:10FM van Dolah, KB Lidie, JS Morey, EAMonroe, JC RyanNOAA, CHARLESTON, SC, United Statesof AmericaKarenia brevis is responsible forbrevetoxin-producing red tides inthe Gulf of Mexico. Current HABforecasting tools are capable ofprojecting the movement of K.brevis blooms towards vulnerablecommunities; however, lack ofinsight into mechanisms controllingcell death in dinoflagellates makesforecasting of bloom terminationcurrently unfeasible. In this studytherefore we sought to identifygenes in K. brevis expressed underconditions leading to cell death. An11,000 gene K. brevis DNA68