The Alexandrium tamarense/catenella / fundyense species complex comprises four genetically differ... more The Alexandrium tamarense/catenella / fundyense species complex comprises four genetically different clades in which the similarity between strains is larger in geographically related species than between geographically distant strains of the same species. These clades are the North Atlantic, the Western European, the Temperate Asian and the Mediterranean clades. The morphological characters currently used to differentiate the species within this complex are the presence or absence of a ventral pore in 1’ plate, the ability to form chains, and the relation between the transdiameter and the length of the cells. In Alexandrium minutum the presence of the ventral pore is not a constant character, and in other species the ability to form longer or shorter chains is strain dependent, and the relation between the transdiameter and length of cells depends on whether or not they form chains. These characters alone are no longer valid to differentiate among species of this complex. In our op...
Journal of Industrial Microbiology & Biotechnology, 2012
Two different strains of microalgae, one raphidophyte and one dinoflagellate, were tested under d... more Two different strains of microalgae, one raphidophyte and one dinoflagellate, were tested under different abiotic conditions with the goal of enhancing lipid production. Whereas aeration was crucial for biomass production, nitrogen deficiency and temperature were found to be the main abiotic parameters inducing the high-level cellular accumulation of neutral lipids. Net neutral lipid production and especially triacylglycerol (TAG) per cell were higher in microalgae (>200% in Alexandrium minutum, and 30% in Heterosigma akashiwo) under treatment conditions (25°C; 330 μM NaNO3) than under control conditions (20°C; 880 μM NaNO3). For both algal species, oil production (free fatty acids plus TAG fraction) was also higher under treatment conditions (57 mg L−1 in A. minutum and 323 mg L−1 in H. akashiwo). Despite the increased production and accumulation of lipids in microalgae, the different conditions did not significantly change the fatty acids profiles of the species analyzed. These...
Información del artículo Resultados del programa de seguimiento de fitoplancton tóxico y biotoxin... more Información del artículo Resultados del programa de seguimiento de fitoplancton tóxico y biotoxinas en las zonas de producción de bivalvos de Cataluña: años 2003-2006 y primer trimestre de 2007.
ABSTRACTThe frequency and intensity ofPseudo-nitzschiaspp. blooms along the coast of Catalonia ha... more ABSTRACTThe frequency and intensity ofPseudo-nitzschiaspp. blooms along the coast of Catalonia have been increasing over the past 20 years. As species from this genus that are documented as toxigenic have been found in local waters, with both toxic and nontoxic species cooccurring in the same bloom, there is a need to develop management tools for discriminating the difference. Currently, differentiation of toxic and nontoxic species requires time-consuming electron microscopy to distinguish taxonomic features that would allow identification as to species, and cryptic species can still remain misidentified. In this study, cells ofPseudo-nitzschiafrom clonal cultures isolated from seawater were characterized to their species identity using scanning electron microscopy, and subsamples of each culture were used to create an internal transcribed spacer 1 (ITS-1), 5.8S, and ITS-2 ribosomal DNA database for development of species-specific quantitative PCR (qPCR) assays. Once developed, the...
Two different strains of microalgae, one raphidophyte and one dinoflagellate, were tested under d... more Two different strains of microalgae, one raphidophyte and one dinoflagellate, were tested under different abiotic conditions with the goal of enhancing lipid production. Whereas aeration was crucial for biomass production, nitrogen deficiency and temperature were found to be the main abiotic parameters inducing the high-level cellular accumulation of neutral lipids. Net neutral lipid production and especially triacylglycerol (TAG) per cell were higher in microalgae (>200% in Alexandrium minutum, and 30% in Heterosigma akashiwo) under treatment conditions (25°C; 330 μM NaNO3) than under control conditions (20°C; 880 μM NaNO3). For both algal species, oil production (free fatty acids plus TAG fraction) was also higher under treatment conditions (57 mg L−1 in A. minutum and 323 mg L−1 in H. akashiwo). Despite the increased production and accumulation of lipids in microalgae, the different conditions did not significantly change the fatty acids profiles of the species analyzed. These profiles consisted of saturated fatty acids (SAFA) and polyunsaturated fatty acids (PUFA) in significant proportions. However, during the stationary phase, the concentrations per cell of some PUFAs, especially arachidonic acid (C20:4n6), were higher in treated than in control algae. These results suggest that the adjustment of abiotic parameters is a suitable and one of the cheapest alternatives to obtain sufficient quantities of microalgal biomass, with high oil content and minimal changes in the fatty acid profile of the strains under consideration.
The Alexandrium tamarense/catenella / fundyense species complex comprises four genetically differ... more The Alexandrium tamarense/catenella / fundyense species complex comprises four genetically different clades in which the similarity between strains is larger in geographically related species than between geographically distant strains of the same species. These clades are the North Atlantic, the Western European, the Temperate Asian and the Mediterranean clades. The morphological characters currently used to differentiate the species within this complex are the presence or absence of a ventral pore in 1’ plate, the ability to form chains, and the relation between the transdiameter and the length of the cells. In Alexandrium minutum the presence of the ventral pore is not a constant character, and in other species the ability to form longer or shorter chains is strain dependent, and the relation between the transdiameter and length of cells depends on whether or not they form chains. These characters alone are no longer valid to differentiate among species of this complex. In our op...
Journal of Industrial Microbiology & Biotechnology, 2012
Two different strains of microalgae, one raphidophyte and one dinoflagellate, were tested under d... more Two different strains of microalgae, one raphidophyte and one dinoflagellate, were tested under different abiotic conditions with the goal of enhancing lipid production. Whereas aeration was crucial for biomass production, nitrogen deficiency and temperature were found to be the main abiotic parameters inducing the high-level cellular accumulation of neutral lipids. Net neutral lipid production and especially triacylglycerol (TAG) per cell were higher in microalgae (>200% in Alexandrium minutum, and 30% in Heterosigma akashiwo) under treatment conditions (25°C; 330 μM NaNO3) than under control conditions (20°C; 880 μM NaNO3). For both algal species, oil production (free fatty acids plus TAG fraction) was also higher under treatment conditions (57 mg L−1 in A. minutum and 323 mg L−1 in H. akashiwo). Despite the increased production and accumulation of lipids in microalgae, the different conditions did not significantly change the fatty acids profiles of the species analyzed. These...
Información del artículo Resultados del programa de seguimiento de fitoplancton tóxico y biotoxin... more Información del artículo Resultados del programa de seguimiento de fitoplancton tóxico y biotoxinas en las zonas de producción de bivalvos de Cataluña: años 2003-2006 y primer trimestre de 2007.
ABSTRACTThe frequency and intensity ofPseudo-nitzschiaspp. blooms along the coast of Catalonia ha... more ABSTRACTThe frequency and intensity ofPseudo-nitzschiaspp. blooms along the coast of Catalonia have been increasing over the past 20 years. As species from this genus that are documented as toxigenic have been found in local waters, with both toxic and nontoxic species cooccurring in the same bloom, there is a need to develop management tools for discriminating the difference. Currently, differentiation of toxic and nontoxic species requires time-consuming electron microscopy to distinguish taxonomic features that would allow identification as to species, and cryptic species can still remain misidentified. In this study, cells ofPseudo-nitzschiafrom clonal cultures isolated from seawater were characterized to their species identity using scanning electron microscopy, and subsamples of each culture were used to create an internal transcribed spacer 1 (ITS-1), 5.8S, and ITS-2 ribosomal DNA database for development of species-specific quantitative PCR (qPCR) assays. Once developed, the...
Two different strains of microalgae, one raphidophyte and one dinoflagellate, were tested under d... more Two different strains of microalgae, one raphidophyte and one dinoflagellate, were tested under different abiotic conditions with the goal of enhancing lipid production. Whereas aeration was crucial for biomass production, nitrogen deficiency and temperature were found to be the main abiotic parameters inducing the high-level cellular accumulation of neutral lipids. Net neutral lipid production and especially triacylglycerol (TAG) per cell were higher in microalgae (>200% in Alexandrium minutum, and 30% in Heterosigma akashiwo) under treatment conditions (25°C; 330 μM NaNO3) than under control conditions (20°C; 880 μM NaNO3). For both algal species, oil production (free fatty acids plus TAG fraction) was also higher under treatment conditions (57 mg L−1 in A. minutum and 323 mg L−1 in H. akashiwo). Despite the increased production and accumulation of lipids in microalgae, the different conditions did not significantly change the fatty acids profiles of the species analyzed. These profiles consisted of saturated fatty acids (SAFA) and polyunsaturated fatty acids (PUFA) in significant proportions. However, during the stationary phase, the concentrations per cell of some PUFAs, especially arachidonic acid (C20:4n6), were higher in treated than in control algae. These results suggest that the adjustment of abiotic parameters is a suitable and one of the cheapest alternatives to obtain sufficient quantities of microalgal biomass, with high oil content and minimal changes in the fatty acid profile of the strains under consideration.
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