RT Dissertation/Thesis
T1 Comparative ecophysiology of two mixotrophic species of "Dinophysis" producers of lipophilic toxins
T2 Ecofisiología comparada de dos especies mixótrofas de "Dinophysis" productoras de toxinas lipofílicas
A1 García Portela, María
K1 2407.01 Cultivo Celular
K1 2407 Biología Celular
K1 2304.01 Plásticos Celulares
AB Dinophysis HAB (Harmful Algae Blooms) produce diarrheogenic toxins (okadaic acid and dinophysis toxins) and pectenotoxins (DSP) resulting in long bans in bivalve culture areas in the European Atlantic coast. The species D. acuminata and D. acuta present different distribution patterns, toxin profiles and cause specific impacts on the resources, being an endemic problem in the Galician Rias with closure seasons between 3 and 9 months. Dinophysis presents the difficulty of its cultivation in laboratory for its mixotropic character. The discovery in 2006 of the trophic chain Teleaulax (cryptophyte) -Mesodinium (ciliate) -Dinophysis (dinoflagellate) was used to obtain cultures of Dinophysis in laboratory for the first time. Despite the similarity between D.acuminata and D.acuta, the spatial and temporal gap in their distribution and development of populations of these species suggests that they may be benefiting from an environmental factor other than ingestion of prey.Main objective: comparative ecophysiology of Dinophysis acuminata and Dinophysis acuta: experimental contribution (mixotrophic cultures) to the description of the niche of each species.- Secondary objectives: 1) Identification of the main source of nitrogen: new production (nitrate) and / or regenerated production (ammonium, urea) versus organic matter from the dam (ciliated Mesodinium) to evaluate the contribution in its growth of the nutrients absorbed from the outside versus input of nutrients obtained by ingesting its only known prey, the ciliate Mesodinium.2) Photosynthetic characterization (P / I curves), toxinological and study of the pigmentary composition in conditions of satiety and fasting of its ciliated prey to understand the physical / biological factors by which the maximum cell of D. acuminata is located in the layer superficial and D. acuta in the pycnocline when they temporarily overlap.3) Biochemical characterization through the comparison of metabolomic profiles (Ifremer, Nantes).4) Response to different conditions of small-scale turbulence (SZN, Naples).Methodology:- Nitrogen sources identfication: incubations of D. acuminata and D. acuta cultures, with the addition of nitrogen compounds marked radioactively as substrate: 15NO3- (Na15NO3), 15NH4 + ((15NH4) 2SO4), (15NH2) 2CO.Analysis by mass spectrometry (UAM, Madrid).- Photosynthetic characterization: cultures of the trophic chain species were exposed to different light intensities (0-650 μmol photons m-2s-1) and qualities (white, green and blue) using different grown mediums.• Pigment composition: HPLC analysis with ICM-CSIC experts in Vigo.• PAM Fluorometry: P / I curves and photosynthetic parameters.• Toxins: analysis of methanolic extracts of Dinophysis samples acclimated to different light intensities in the CIMA (Vilaxoán, Xunta de Galicia), using a mass spectrometer for UHPLC analysis.- Biochemical characterization through the comparison of metabolomic profiles:• Biology: Curves and estimation of growth rates.• Phylogenetics: sequencing of the Danish strain of M. rubrum.• Toxins: analysis of hydrolyzed samples (acid hydrolysis) to explore the presence of diol-esters in D. acuta and D. acuminata (directed analyzes).Measurement systems:• SistemA: HRMS (QTOF 6550) / SistemB: LRMS / MS (API 4000 QTrap)• Metabolomics (non-targeted analysis: MassHunter Workstation Qualitative Analysis software.- Response to different conditions of small-scale turbulence: Use of the TURBOGEN device capable of producing levels of microscale turbulence similar to those recorded in the natural environment, in computer-controlled mesocosms, with a homogeneous light distribution. Three experiments were performed with 3 levels of turbulence (ɛ): high, medium and low (10-3,10-5 and 10-6 m2 s-3, respectively).
YR 2019
FD 2019-03-06
LK http://hdl.handle.net/11093/1202
UL http://hdl.handle.net/11093/1202
LA eng
NO Ministerio de Economía y Competitividad de España | Ref. BES-2014-067832
DS Investigo
RD 29-nov-2023