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 20061 National Ocean Service, NOAA, SILVERSPRING, MD, United States of America2 NOAA/GLERL, MUSKEGON, MI, UnitedStates of America3 NOAA/NCCOS, BEAUFORT, NC, UnitedStates of AmericaThe toxic cyanobacterium,Microcystis aeruginosa, hasbecome a dominant component ofthe summer phytoplanktonpopulation in Saginaw Bay andwestern Lake Erie, USA. Expansiveblooms of Microcystis have causedconsiderable concern to the GreatLakes region due to the use ofthese waters for recreation. Thetoxin, microcystin, has beenobserved in both regions above therecommended limit of 1 µg L -1 andposes a threat to human health.Microcystis blooms have uniquescattering and absorptionproperties, due to the production ofsurface scum and the dominantaccessory pigment, phycocyanin.In an effort to better detect andmonitor these blooms, satellitederived products from SeaWiFSand MODIS which highlight theseoptical properties will be comparedwith in situ measurements ofMicrocystis and its toxin, from 2004and 2005. Phycocyanin has anabsorption peak centered at 620nm. Therefore, changes in theabsorption spectra centered at thiswavelength will be investigatedusing spectral curvature methods.In addition, the use of a particulatebackscatter ratio method will betested for its ability to detect theseblooms. The ability to detectsurface scum using the MODISnear-infrared band (865 nm) may becompromised by shallow waterdepth but looks promising in deeperwater.PO.09-10Fatty acid esters of pectenotoxinseco acids in Norwegian andIrish musselsSession: PO.09 - Toxin synthesis andchemical structure of toxinsT. Torgersen 1 , AL Wilkins 2 , NRehman 3 , T Rundberget 1 , D Petersen 4 ,P Hess 3 , F Rise 4 , CO Miles 11 National Veterinary Institute, OSLO,Norway2 The University of Waikato, HAMILTON,New Zealand3 Marine Institute, GALWAY, Ireland4 University of Oslo, OSLO, NorwayPectenotoxin-2 (PTX-2) from marinedinoflagellates of the genusDinophysis is rapidly hydrolyzed inmany shellfish to pectenotoxin-2seco acid (PTX-2 SA), whichisomerises to 7- 7-epi-PTX-2 SA.Pectenotoxin-12 (PTX-12) from thesame dinoflagellates is alsobelieved to be hydrolyzed inshellfish to PTX-12 SAs, which arein equilibrium with isomerspresumed to be 7-epi-PTX-12 SAs.Three series of fatty acid esters ofPTX-2 SA and 7-epi-PTX-2 SAwere detected by LC-MS analysis ofan extract from Irish blue mussels(Mytilus edulis). Fatty acids wereconjugated on C-11, C-33 and C-37of the PTX-skeleton. In methanolicextracts from two samples of bluemussels from Norway, three seriesof fatty acid esters of PTX-2 SA,with only minor accompanyingamounts of the 7-epi-analogues,and a series of fatty acid esters ofPTX-12 SAs and its presumed 7-epi-analogues, were detected.The location of the fatty acid esterlinkages were identified by LC-MSnin positive- and negative-ionizationmodes, LC-MS analysis of theproducts of the reaction with sodiumperiodate, and NMR analysis ofpurified samples of the mostabundant derivatives. For PTX-2293