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 2006detected throughout the yearachieving abundances up to1.33x10 5 cells g -1 fwm epiphyticallyon the marine phanerogamCymodocea nodosa in November,while the presence of the otherProrocentrum species was morescarce and restricted to the warmperiod.PO.13-17Occurrence of species from thegenus Pseudo-nitzschia in thesouthwestern Atlantic andSouthern OceanSession: PO.13 - Regional eventsGO Almandoz 1 , ME Ferrario 1 , GAFerreyra 2 , IR Schloss 21 Facultad de Cs. Naturales y Museo(UNLP), LA PLATA, Argentina2 Instituto Antartico Argentino, BUENOSAIRES, ArgentinaThe distribution of Pseudo-nitzschiaspecies and its relationship withmain environmental factors werestudied in surface waters of theArgentine and Weddell Seas (38-55°S and 61-77°S, respectively).Both qualitative and quantitativesamples, collected during summerand fall 2003, summer 2004 andspring 2005 were examined usinglight and scanning electronmicroscopy. Several Pseudonitzschiaspecies were found in theArgentine Sea, including P.americana, P. australis, P.calliantha, P. fraudulenta, P. heimii,P. lineola, P. pungens, P.subcurvata, P. turgidula and P.turgiduloides. Pseudo-nitzschiapungens and P. australis were themost common species recorded,especially in waters with elevatedtemperatures and salinities (around15 ºC, 33.8psu) and low nutrientconcentrations. The rest of thespecies showed a more restricteddistribution. Pseudo-nitzschiacalliantha and the epiphytic P.americana, both reported for thefirst time in Argentinean waters,were found only during spring. Alower number of species was foundin the cold (0.6 to -1.6 ºC), nutrientrichwaters of the Weddell Sea.Notably, P. lineola, P.prolongatoides, P. subcurvata andP. turgiduloides showed awidespread distribution, while P.heimii and P. turgidula wereconfined tp northward of 62ºS.Morphometric data, abundancesand ecological preferences aregiven and compared with previousstudies.PO.02-07New insights into the higherorder organization of thedinoflagellate chromosomes:evidence of eukaryoticdifferentiationsSession: PO.02 - GenomicsEAF Alverca 1 , A Cuadrado 2 , S Franca 1 ,S Moreno Díaz de la Espina 31 INSA, LISBON, Portugal2 Universidad de Alcalá de Henares,MADRID, Spain3 Centro de Investigaciones Biológicas,MADRID, SpainDinoflagellates are eukaryoticprotists with a unique genome andchromosome organization. Theylack histones and nucleosomes,being therefore considered the onlyliving knockouts of these proteins.They have distinct interphasicchromosomes stabilized by metalcations and DNA-RNA hybrids.Their DNA has a high G+C content,highly methylated and rare basesand their genomes lack thecanonical TATA box, showingspecific regulatory sequences intheir promoters, as well as lineararrangement of genes and gene124