Santiago Fraga - Academia.edu (original) (raw)
Papers by Santiago Fraga
The presence of the paralytic shellfish poisoning (PSP) dinoflagellate Alexandrium catenella in t... more The presence of the paralytic shellfish poisoning (PSP) dinoflagellate Alexandrium catenella in the north western (NW) Mediterranean Sea has been known since 1983. From this date on, the species has spread along the Spanish and Italian coastlines. Information concerning A. catenella isolates in the NW Mediterranean Sea was gained through phylogenetic studies. Twenty established toxic cultures of A. catenella taken from various NW Mediterranean Sea locations were analysed by nucleotide sequencing of the 5.8S rDNA and internal transcribed spacer regions. These rDNA ribosomal markers resulted useful in delineating the phylogenetic position of this species in the genus Alexandrium as well as in determining relationships between A. catenella isolates from different geographic areas. The phylogenetic position of the Mediterranean A. catenella ribotype, when compared to the “Alexandrium tamarense/catenella/fundyense species complex”, fits this species complex well. All the Mediterranean A....
The morphology and molecular phylogenetic relationships of <i>Coolia</i> species isol... more The morphology and molecular phylogenetic relationships of <i>Coolia</i> species isolated from Brazil, including <i>C. malayensis, C. tropicalis</i> and a new lineage of the <i>Coolia canariensis</i> complex, are presented. Morphology was investigated by light and scanning electron microscopy. No significant morphological differences between the Brazilian strains and other geographically distant strains of <i>C. malayensis</i> and <i>C. tropicalis</i> were observed. In LSU and ITS rDNA phylogenies <i>C. malayensis</i> and <i>C. tropicalis</i> sequences from Brazil branched within the clade of these species with strains isolated from elsewhere. Phylogenetic relationships (LSU rDNA) within the <i>C. canariensis</i> species complex support the existence of three cryptic species. No morphological difference was discernible among species in this complex. Additional molecular, morphological and...
The presence of the paralytic shellfish poisoning (PSP) dinoflagellate Alexandrium catenella in t... more The presence of the paralytic shellfish poisoning (PSP) dinoflagellate Alexandrium catenella in the north western (NW) Mediterranean Sea has been known since 1983. From this date on, the species has spread along the Spanish and Italian coastlines. Information concerning A. catenella isolates in the NW Mediterranean Sea was gained through phylogenetic studies. Twenty established toxic cultures of A. catenella taken from various NW Mediterranean Sea locations were analysed by nucleotide sequencing of the 5.8S rDNA and internal transcribed spacer regions. These rDNA ribosomal markers resulted useful in delineating the phylogenetic position of this species in the genus Alexandrium as well as in determining relationships between A. catenella isolates from different geographic areas. The phylogenetic position of the Mediterranean A. catenella ribotype, when compared to the “Alexandrium tamarense/catenella/fundyense species complex”, fits this species complex well. All the Mediterranean A....
The morphology and molecular phylogenetic relationships of <i>Coolia</i> species isol... more The morphology and molecular phylogenetic relationships of <i>Coolia</i> species isolated from Brazil, including <i>C. malayensis, C. tropicalis</i> and a new lineage of the <i>Coolia canariensis</i> complex, are presented. Morphology was investigated by light and scanning electron microscopy. No significant morphological differences between the Brazilian strains and other geographically distant strains of <i>C. malayensis</i> and <i>C. tropicalis</i> were observed. In LSU and ITS rDNA phylogenies <i>C. malayensis</i> and <i>C. tropicalis</i> sequences from Brazil branched within the clade of these species with strains isolated from elsewhere. Phylogenetic relationships (LSU rDNA) within the <i>C. canariensis</i> species complex support the existence of three cryptic species. No morphological difference was discernible among species in this complex. Additional molecular, morphological and...
Ecological Studies, 2018
The Scientific Committee of the CRP on Fjords and Coastal Embayments proposed a second OSM to hig... more The Scientific Committee of the CRP on Fjords and Coastal Embayments proposed a second OSM to highlight this progress and the importance of a comparative approach to improve our understanding of HABs. This second OSM focused on four themes: (1) Life history of HAB species; (2) Chemical ecological and toxin interactions; (3) Genetic diversity and (4) Transport and
Biological and Geological Perspectives of Dinoflagellates
ABSTRACT Specimens belonging to the mixotrophic genus Fragilidium were isolated from coastal wate... more ABSTRACT Specimens belonging to the mixotrophic genus Fragilidium were isolated from coastal waters of west Iberia (NE Atlantic). Based on plate morphology and LSU rDNA sequences two species were identified: F. subglobosum and F . cf. duplocampanaeforme . The life-cycle is similar in both species. The asexual cycle is characterized by an alternation between a thecate motile stage and a reproductively active coccoid stage. The sexual cycle is characterized by heterogamous anisogamy and includes a sexual benthic hypnozygote. The first apical plate in vegetative cells does not touch the apical pore plate while in gametes it does, confirming in Fragilidium the homology of what is frequently referred as the first pre-cingular with the first apical plate in Gonyaulacales. Both species were observed to prey on Ceratium horridum . Molecular phylogenetic analyses with strains isolated from other geographical areas and Fragilidium gene sequences available in GenBank identified three different clades. One clade comprising F. subglobosum from the type locality and strains from Iberian waters; a second clade comprising the morphological species F. cf. duplocampanaeforme from Iberia and other strains from NE Atlantic, SE Atlantic and S Pacific and a third clade with an unassigned species from the SE Atlantic.
Surveys of two epiphytic dinoflagellates Coolia monotis and Ostreopsis sp. were conducted in a br... more Surveys of two epiphytic dinoflagellates Coolia monotis and Ostreopsis sp. were conducted in a brackish area of Sicily(Capo Peloro Lagoons, Messina, Italy). Phytoplankton concentrates from net hauls and macroalgal samples permitted to detect these species even at lower concentrations. Culturing techniques were optimized and isolated strains of Ostreopsis revealed toxicity(palytoxin) whereas C. monotis strains were non toxic.
Ecological Studies, 2018
The Scientific Committee of the CRP on Fjords and Coastal Embayments proposed a second OSM to hig... more The Scientific Committee of the CRP on Fjords and Coastal Embayments proposed a second OSM to highlight this progress and the importance of a comparative approach to improve our understanding of HABs. This second OSM focused on four themes: (1) Life history of HAB species; (2) Chemical ecological and toxin interactions; (3) Genetic diversity and (4) Transport and
Introduccion: En este capitulo se hace una revision sobre los conceptos basicos utilizados en tax... more Introduccion: En este capitulo se hace una revision sobre los conceptos basicos utilizados en taxonomia y en los distintos conceptos de especie con especial enfasis en los dinoflagelados. Se aborda la necesidad de la taxonomia para estudios ecologicos y de biodiversidad. Se describe el desarrollo historico de la taxonomia y los distintos conceptos de especie utilizados en los estudios de dinoflagelados. Se definen especies cripticas, semicripticas y pseudo-cripticas y se revisan las propuestas taxonomicas actuales para resolver el problema de las especies cripticas y su caracterizacion, entre ellas la llamada taxonomia integradora que incluye mas de un tipo de caracteres para la definicion de especies. Se describen las principales caracteristicas de los dinoflagelados, y se revisan los dinoflagelados nocivos en base al tipo de danos que estos pueden producir. Dentro de la descripcion de los criterios utilizados para taxonomia de dinoflagelados, se propone un sistema de nomenclatura ...
Biological and Geological Perspectives of Dinoflagellates
ABSTRACT Specimens belonging to the mixotrophic genus Fragilidium were isolated from coastal wate... more ABSTRACT Specimens belonging to the mixotrophic genus Fragilidium were isolated from coastal waters of west Iberia (NE Atlantic). Based on plate morphology and LSU rDNA sequences two species were identified: F. subglobosum and F . cf. duplocampanaeforme . The life-cycle is similar in both species. The asexual cycle is characterized by an alternation between a thecate motile stage and a reproductively active coccoid stage. The sexual cycle is characterized by heterogamous anisogamy and includes a sexual benthic hypnozygote. The first apical plate in vegetative cells does not touch the apical pore plate while in gametes it does, confirming in Fragilidium the homology of what is frequently referred as the first pre-cingular with the first apical plate in Gonyaulacales. Both species were observed to prey on Ceratium horridum . Molecular phylogenetic analyses with strains isolated from other geographical areas and Fragilidium gene sequences available in GenBank identified three different clades. One clade comprising F. subglobosum from the type locality and strains from Iberian waters; a second clade comprising the morphological species F. cf. duplocampanaeforme from Iberia and other strains from NE Atlantic, SE Atlantic and S Pacific and a third clade with an unassigned species from the SE Atlantic.
Surveys of two epiphytic dinoflagellates Coolia monotis and Ostreopsis sp. were conducted in a br... more Surveys of two epiphytic dinoflagellates Coolia monotis and Ostreopsis sp. were conducted in a brackish area of Sicily(Capo Peloro Lagoons, Messina, Italy). Phytoplankton concentrates from net hauls and macroalgal samples permitted to detect these species even at lower concentrations. Culturing techniques were optimized and isolated strains of Ostreopsis revealed toxicity(palytoxin) whereas C. monotis strains were non toxic.
The presence of the paralytic shellfish poisoning (PSP) dinoflagellate Alexandrium catenella in t... more The presence of the paralytic shellfish poisoning (PSP) dinoflagellate Alexandrium catenella in the north western (NW) Mediterranean Sea has been known since 1983. From this date on, the species has spread along the Spanish and Italian coastlines. Information concerning A. catenella isolates in the NW Mediterranean Sea was gained through phylogenetic studies. Twenty established toxic cultures of A. catenella taken from various NW Mediterranean Sea locations were analysed by nucleotide sequencing of the 5.8S rDNA and internal transcribed spacer regions. These rDNA ribosomal markers resulted useful in delineating the phylogenetic position of this species in the genus Alexandrium as well as in determining relationships between A. catenella isolates from different geographic areas. The phylogenetic position of the Mediterranean A. catenella ribotype, when compared to the “Alexandrium tamarense/catenella/fundyense species complex”, fits this species complex well. All the Mediterranean A....
The morphology and molecular phylogenetic relationships of <i>Coolia</i> species isol... more The morphology and molecular phylogenetic relationships of <i>Coolia</i> species isolated from Brazil, including <i>C. malayensis, C. tropicalis</i> and a new lineage of the <i>Coolia canariensis</i> complex, are presented. Morphology was investigated by light and scanning electron microscopy. No significant morphological differences between the Brazilian strains and other geographically distant strains of <i>C. malayensis</i> and <i>C. tropicalis</i> were observed. In LSU and ITS rDNA phylogenies <i>C. malayensis</i> and <i>C. tropicalis</i> sequences from Brazil branched within the clade of these species with strains isolated from elsewhere. Phylogenetic relationships (LSU rDNA) within the <i>C. canariensis</i> species complex support the existence of three cryptic species. No morphological difference was discernible among species in this complex. Additional molecular, morphological and...
The presence of the paralytic shellfish poisoning (PSP) dinoflagellate Alexandrium catenella in t... more The presence of the paralytic shellfish poisoning (PSP) dinoflagellate Alexandrium catenella in the north western (NW) Mediterranean Sea has been known since 1983. From this date on, the species has spread along the Spanish and Italian coastlines. Information concerning A. catenella isolates in the NW Mediterranean Sea was gained through phylogenetic studies. Twenty established toxic cultures of A. catenella taken from various NW Mediterranean Sea locations were analysed by nucleotide sequencing of the 5.8S rDNA and internal transcribed spacer regions. These rDNA ribosomal markers resulted useful in delineating the phylogenetic position of this species in the genus Alexandrium as well as in determining relationships between A. catenella isolates from different geographic areas. The phylogenetic position of the Mediterranean A. catenella ribotype, when compared to the “Alexandrium tamarense/catenella/fundyense species complex”, fits this species complex well. All the Mediterranean A....
The morphology and molecular phylogenetic relationships of <i>Coolia</i> species isol... more The morphology and molecular phylogenetic relationships of <i>Coolia</i> species isolated from Brazil, including <i>C. malayensis, C. tropicalis</i> and a new lineage of the <i>Coolia canariensis</i> complex, are presented. Morphology was investigated by light and scanning electron microscopy. No significant morphological differences between the Brazilian strains and other geographically distant strains of <i>C. malayensis</i> and <i>C. tropicalis</i> were observed. In LSU and ITS rDNA phylogenies <i>C. malayensis</i> and <i>C. tropicalis</i> sequences from Brazil branched within the clade of these species with strains isolated from elsewhere. Phylogenetic relationships (LSU rDNA) within the <i>C. canariensis</i> species complex support the existence of three cryptic species. No morphological difference was discernible among species in this complex. Additional molecular, morphological and...
Ecological Studies, 2018
The Scientific Committee of the CRP on Fjords and Coastal Embayments proposed a second OSM to hig... more The Scientific Committee of the CRP on Fjords and Coastal Embayments proposed a second OSM to highlight this progress and the importance of a comparative approach to improve our understanding of HABs. This second OSM focused on four themes: (1) Life history of HAB species; (2) Chemical ecological and toxin interactions; (3) Genetic diversity and (4) Transport and
Biological and Geological Perspectives of Dinoflagellates
ABSTRACT Specimens belonging to the mixotrophic genus Fragilidium were isolated from coastal wate... more ABSTRACT Specimens belonging to the mixotrophic genus Fragilidium were isolated from coastal waters of west Iberia (NE Atlantic). Based on plate morphology and LSU rDNA sequences two species were identified: F. subglobosum and F . cf. duplocampanaeforme . The life-cycle is similar in both species. The asexual cycle is characterized by an alternation between a thecate motile stage and a reproductively active coccoid stage. The sexual cycle is characterized by heterogamous anisogamy and includes a sexual benthic hypnozygote. The first apical plate in vegetative cells does not touch the apical pore plate while in gametes it does, confirming in Fragilidium the homology of what is frequently referred as the first pre-cingular with the first apical plate in Gonyaulacales. Both species were observed to prey on Ceratium horridum . Molecular phylogenetic analyses with strains isolated from other geographical areas and Fragilidium gene sequences available in GenBank identified three different clades. One clade comprising F. subglobosum from the type locality and strains from Iberian waters; a second clade comprising the morphological species F. cf. duplocampanaeforme from Iberia and other strains from NE Atlantic, SE Atlantic and S Pacific and a third clade with an unassigned species from the SE Atlantic.
Surveys of two epiphytic dinoflagellates Coolia monotis and Ostreopsis sp. were conducted in a br... more Surveys of two epiphytic dinoflagellates Coolia monotis and Ostreopsis sp. were conducted in a brackish area of Sicily(Capo Peloro Lagoons, Messina, Italy). Phytoplankton concentrates from net hauls and macroalgal samples permitted to detect these species even at lower concentrations. Culturing techniques were optimized and isolated strains of Ostreopsis revealed toxicity(palytoxin) whereas C. monotis strains were non toxic.
Ecological Studies, 2018
The Scientific Committee of the CRP on Fjords and Coastal Embayments proposed a second OSM to hig... more The Scientific Committee of the CRP on Fjords and Coastal Embayments proposed a second OSM to highlight this progress and the importance of a comparative approach to improve our understanding of HABs. This second OSM focused on four themes: (1) Life history of HAB species; (2) Chemical ecological and toxin interactions; (3) Genetic diversity and (4) Transport and
Introduccion: En este capitulo se hace una revision sobre los conceptos basicos utilizados en tax... more Introduccion: En este capitulo se hace una revision sobre los conceptos basicos utilizados en taxonomia y en los distintos conceptos de especie con especial enfasis en los dinoflagelados. Se aborda la necesidad de la taxonomia para estudios ecologicos y de biodiversidad. Se describe el desarrollo historico de la taxonomia y los distintos conceptos de especie utilizados en los estudios de dinoflagelados. Se definen especies cripticas, semicripticas y pseudo-cripticas y se revisan las propuestas taxonomicas actuales para resolver el problema de las especies cripticas y su caracterizacion, entre ellas la llamada taxonomia integradora que incluye mas de un tipo de caracteres para la definicion de especies. Se describen las principales caracteristicas de los dinoflagelados, y se revisan los dinoflagelados nocivos en base al tipo de danos que estos pueden producir. Dentro de la descripcion de los criterios utilizados para taxonomia de dinoflagelados, se propone un sistema de nomenclatura ...
Biological and Geological Perspectives of Dinoflagellates
ABSTRACT Specimens belonging to the mixotrophic genus Fragilidium were isolated from coastal wate... more ABSTRACT Specimens belonging to the mixotrophic genus Fragilidium were isolated from coastal waters of west Iberia (NE Atlantic). Based on plate morphology and LSU rDNA sequences two species were identified: F. subglobosum and F . cf. duplocampanaeforme . The life-cycle is similar in both species. The asexual cycle is characterized by an alternation between a thecate motile stage and a reproductively active coccoid stage. The sexual cycle is characterized by heterogamous anisogamy and includes a sexual benthic hypnozygote. The first apical plate in vegetative cells does not touch the apical pore plate while in gametes it does, confirming in Fragilidium the homology of what is frequently referred as the first pre-cingular with the first apical plate in Gonyaulacales. Both species were observed to prey on Ceratium horridum . Molecular phylogenetic analyses with strains isolated from other geographical areas and Fragilidium gene sequences available in GenBank identified three different clades. One clade comprising F. subglobosum from the type locality and strains from Iberian waters; a second clade comprising the morphological species F. cf. duplocampanaeforme from Iberia and other strains from NE Atlantic, SE Atlantic and S Pacific and a third clade with an unassigned species from the SE Atlantic.
Surveys of two epiphytic dinoflagellates Coolia monotis and Ostreopsis sp. were conducted in a br... more Surveys of two epiphytic dinoflagellates Coolia monotis and Ostreopsis sp. were conducted in a brackish area of Sicily(Capo Peloro Lagoons, Messina, Italy). Phytoplankton concentrates from net hauls and macroalgal samples permitted to detect these species even at lower concentrations. Culturing techniques were optimized and isolated strains of Ostreopsis revealed toxicity(palytoxin) whereas C. monotis strains were non toxic.