Protein phosphatase inhibition assays for okadaic acid detection in shellfish: matrix effects, applicability and comparison with LC-MS/MS analysis

The applicability of the protein phosphatase inhibition assay (PPIA) to the determination of okadaic acid (OA) and its acyl derivatives in shellfish samples has been investigated, using a recombinant PP2A and a commercial one. Mediterranean mussel, wedge clam, Pacific oyster and flat oyster have been chosen as model species. Shellfish matrix loading limits for the PPIA have been established, according to the shellfish species and the enzyme source. A synergistic inhibitory effect has been observed in the presence of OA and shellfish matrix, which has been overcome by the application of a correction factor (0.48). Finally, Mediterranean mussel samples obtained from Rı´a de Arousa during a DSP closure associated to Dinophysis acuminata, determined as positive by the mouse bioassay, have been analysed with the PPIAs. The OA equivalent contents provided by the PPIAs correlate satisfactorily with those obtained by liquid chromatography–tandem mass spectrometry (LC–MS/MS).

Genome Biology and Evolution of the Animal Kingdom

Estudi realitzat a partir d’una estada a la Institut J.W. Jenkinson Laboratory for Evolution and Development of the University of Oxford, Regne Unit, entre 2010 i 2012. He estat membre del laboratori del Professor Peter W.H. Holland com a becari post-doctoral Beatriu de Pinós des de setembre de 2010 al setembre de 2012. El nostre projecte de recerca se centra en l'anàlisi genòmic comparatiu del Regne Animal, tot explorant el contingut dels genomes a través de totes les branques de l'arbre dels animals. Totes les referències a les meves publicacions durant aquest post-doc es poden trobar a http://about.me/jordi_paps. Crec que el nombre i la qualitat dels resultats del meu post-doc, un total de 8 publicacions incloent dos articles a la prestigiosa revista Nature, són prova de l'èxit d'aquest post-doc. Prof Peter W. H. Holland (Departament de Zoologia de la Universitat d'Oxford) i jo som coautors de tres articles de genòmica comparativa, resultats directes d'aquest projecte: 1) comparació de families gèniques entre vertebrats invertebrats (Briefings in Functional Genomics), 2) el genoma de l'ostra (publicat a la revista Nature), i 3) els genomes de 6 platihelmints paràsits (acceptat també a Nature). A més, tenim altres 2 treballs en preparació. Un d'ells analitza l'evolució, expressió i funció dels gens Hox al a la tènia Hymenolepis. El perfil fi d'aquests gens clau del desenvolupament esclareix els canvis d'estil de vida dels organismes. A més, durant aquest últim post-doc he participat en diverses col•laboracions, incloent anàlisi de gens d'envelliment a cucs plans, un estudi sobre la filogènia del grup Gastrotricha, una revisió de l'evolució phylum Platyhelminthes, així com un capítol d'un llibre sobre l'evolució dels animals bilaterals. Finalment, gràcies a la beca Beatriu de Pinós, el Prof. Peter W.H. Holland m'ha convidat a formar part del seu equip com un investigador post-doctoral en el seu projecte ERC Advance actual sobre duplicacions genòmiques.

Crassostrea patagonica (d'Orbigny, 1842) shell concentrations from the late Miocene Rio Negro province, NE Patagonia, Argentina

The Río Negro Formation (late Miocene-early Pliocene) mainly consists of continental deposits, but it contains a middle member of marine origin. It represents a transgressive-regressive sequence that can be seen at several outcrops along the N Patagonian coast. The taphonomical approach to the El Espigón marine deposits permits the identification of four main layers containing different kinds of skeletal accumulation, which mainly consist of oyster shells [Crassostrea patagonica (D'Orbigny, 1842)]. These concentrations display three different morphologies (pouches, pavements and bouquets) with a different taphonomic signature. These deposits were formed in shallow marine environments influenced by wave activity that produced valve concentrations of different entities. They contain several shell beds that represent event, composite, hiatal to lag skeletal concentrations. Traces of bioturbation in the sediment (Thalassinoides, Teichichnus) and bioerosion on the shells (Entobia, Gastrochaeonolites, Caulostrepsis), and encrusters (cirripeds, bryozoans), are also abundant in the outcrop and consititue common components of these Miocene materials. Layers 1 and 2 of the sequence were deposited in shoreface/foreshore environments at the beginning of a highstand systems tract, while layers 3 and 4 were deposited at the end, or at the beginning of a forced regression, in foreshore environments. A final erosional episode cut the top of the layer 4, which truncated the abundant bioturbaation developed there.