No difference found in ribosomal DNA sequences from physiologically diverse clones of Karenia brevis (Dinophyceae) from the Gulf of Mexico

Loret, Pascale

doi:10.1093/plankt/24.7.735

Cited by 47 publications

(42 citation statements)

References 23 publications

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“…Toxin levels of K. brevis vary among and within strains depending on culture conditions and growth phase (Baden & Tomas 1988, Roszell et al 1990, Loret et al 2002. In the present experiments, we measured the brevetoxin content of cells on the day of experimentation.…”

Section: Variability In Toxin Contentmentioning

confidence: 86%

Toxicity and nutritional inadequacy of Karenia brevis: synergistic mechanisms disrupt top-down grazer control

Waggett¹,

Hardison²,

Tester³

2012

Mar. Ecol. Prog. Ser.

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Zooplankton grazers are capable of influencing food-web dynamics by exerting topdown control over phytoplankton prey populations. Certain toxic or unpalatable algal species have evolved mechanisms to disrupt grazer control, thereby facilitating the formation of massive, monospecific blooms. The harmful algal bloom (HAB)-forming dinoflagellate Karenia brevis has been associated with lethal and sublethal effects on zooplankton that may offer both direct and indirect support of bloom formation and maintenance. Reductions in copepod grazing on K. brevis have been attributed to acute physiological incapacitation and nutritional inadequacy. To evaluate the potential toxicity or nutritional inadequacy of K. brevis, food removal and egg production experiments were conducted using the copepod Acartia tonsa and K. brevis strains CCMP 2228, Wilson, and SP-1, characterized using liquid chromatography-mass spectrometry (LC-MS) as having high, low, and no brevetoxin levels, respectively. Variable grazing rates were found in experiments involving mixtures of toxic CCMP 2228 and Wilson strains. However, in experiments with toxic CCMP 2228 and non-toxic SP-1 strains, A. tonsa grazed SP-1 at significantly higher rates than the toxic alternative. Additionally, A. tonsa experienced significantly greater mortality when exposed to toxic K. brevis strains, particularly after prolonged exposure. Egg production rates of copepods fed toxic K. brevis strains were similar to those of starved copepods, while those of copepods fed non-toxic SP-1 and the nutritious Rhodomonas salina were significantly higher. Analysis indicates that K. brevis impacts grazer populations via multiple synergistic mechanisms: (1) decreased ingestion rates, (2) decreased egg production, and (3) increased mortality of copepods through a combination of toxicity and nutritional inadequacy.

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Section: Variability In Toxin Contentmentioning

confidence: 86%

Toxicity and nutritional inadequacy of Karenia brevis: synergistic mechanisms disrupt top-down grazer control

Waggett¹,

Hardison²,

Tester³

2012

Mar. Ecol. Prog. Ser.

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“…As the criteria used for species differentiation based on genetic information are continuously debated (Manhart and McCourt, 1992;Taylor, 1993;Coyne and Orr, 2004), it will continue to be necessary to use both morphotypes and genotypes when defining strains, especially when ascertaining the extent of speciation and strain development of an organism. Some taxonomical methods will probably need to be upgraded by using new genetic regions for strain identification, as proof exists that morphologically or toxically variable dinoflagellate strains such as Karenia brevis and Pfiesteria piscida (Loret et al, 2002;Tengs et al, 2003) have identical rDNA sequences. Open questions also remain as to how sexual reproduction and polyploidy of dinoflagellates (Pfiester and Anderson, 1987;Faust, 1992) compound genetic variability and speciation.…”

Section: Discussionmentioning

confidence: 99%

Morphology and rDNA phylogeny of a Mediterranean <em>Coolia monotis</em> (Dinophyceae) strain from Greece

Dolapsakis¹,

Kilpatrick²,

Economou‐Amilli³

et al. 2006

Sci. Mar.

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SUMMARY: Sequences of LSU and SSU ribosomal RNA genes and phylogeny have not been widely investigated for the dinoflagellate Coolia monotis Meunier, and no information is available on the small and large rDNA subunits of Mediterranean strains. A strain isolated from the Thermaikos Gulf in northern Greece was identified as C. monotis-a new record for the Greek algal flora-using thecal morphology by light, epifluorescence and scanning electron microscopy. The small subunit and partial (D1/D2) large subunit sequences were analyzed and compared to other strains of C. monotis and dinoflagellates from various regions. Thecal architecture showed that the Greek strain of C. monotis was phenotypically similar, but not identical, to other strains reported in literature. The partial LSU sequence (700 bp) was found to vary by 113 bp positions (16%) from the C. monotis strain from New Zealand, whereas the SSU (1757 bp) had 15 bp differences (0.85%) from the strain from Norway. Phylogenetic tree construction showed that the Greek strain fell within the Coolia clade and had a close relationship with the families Ostreopsidaceae and Goniodomaceae of the order Gonyaulacales. Preliminary findings suggest the existence of different genotype strains of C. monotis with large intraspecific genetic variability and minimal morphological differentiation (similar phenotypes). Certain ecological and evolutionary implications of these findings are discussed.Keywords: Coolia monotis, Greece, microscopy, rDNA, taxonomy, phylogeny. RESUMEN: MORFOLOGÍA Y FILOGENIA DEL RDNA DE UNA SUBESPECIE MEDITERRÁNEA DE COOLIA MONOTIS (DINOPHYCEAE) DE GRECIA. -Las secuencias de los genes del RNA de las subunidades ribosomales grandes y pequeñas (LSU y SSU, respectivamente) y la filogenia del dinoflagelado Coolia monotis Meunier han sido poco investigadas, y no hay información disponible sobre los genes LSU y SSU de subespecies mediterráneas. Una subespecie aislada del golfo de Thermaikos en el norte de Grecia fue identificada como C. monotis -una nueva aportación a la flora algal griega-por medio de la morfología de la teca observada a través de microscopía óptica, de epifluorescia y electrónica. Las secuencias correspondientes a la subunidad pequeña y a la parte (D1/D2) de la subunidad grande fueron analizadas y comparadas a las de otras subespecies de C. monotis y otras especies de dinoflagelados de diversas regiones. La arquitectura de la teca mostró que la subespecie griega de C. monotis era fenotípicamente similar, pero no idéntica, a otras subespecies registradas en la literatura. Se encontró que la secuencia parcial de la LSU (700 pares de bases o bp) difería de la de C. monotis de Nueva Zelanda en las posiciones de 113 bp (16%), mientras que la SSU (1757 bp) se diferenciaba en 15 bp (0.85%) de la subespecie de Noruega. La construcción del árbol filogenetico demostró que la subespecie griega se situaba dentro de la rama de Coolia y presentaba una relación cercana con las familias Ostreopsidaceae y Goniodomaceae del orden Gonyaulacales. Resultados pre...

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“…K. brevis strains JR, JR1 (which are identical to CCMP2281. CCMP2281 and JR1 are reportedly axenic) and NOAA1 (also known as Charlotte Harbor (Loret et al, 2002)) were obtained from the US EPA Gulf Ecology Division Laboratory in Gulf Breeze, Florida. Prorocentrum lima was obtained from the collection of Daniel Baden while at the University of Miami.…”

Section: Dinoflagellate Strains and Culturing Conditionsmentioning

confidence: 99%

Localization of polyketide synthase encoding genes to the toxic dinoflagellate Karenia brevis

et al. 2005

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Karenia brevis is a toxic marine dinoflagellate endemic to the Gulf of Mexico. Blooms of this harmful alga cause fish kills, marine mammal mortalities and neurotoxic shellfish poisonings. These harmful effects are attributed to a suite of polyketide secondary metabolites known as the brevetoxins. The carbon framework of all polyketides is assembled by a polyketide synthase (PKS). Previously, PKS encoding genes were amplified from K. brevis culture and their similarity to a PKS gene from the closely related protist, Cryptosporidium parvum, suggested that these genes originate from the dinoflagellate. However, K. brevis has not been grown axenically. The associated bacteria might be the source of the toxins or the PKS genes. Herein we report the localization of PKS encoding genes by a combination of flow cytometry/PCR and fluorescence in situ hybridization (FISH). Two genes localized exclusively to K. brevis cells while a third localized to both K. brevis and associated bacteria. While these genes have not yet been linked to toxin production, the work describes the first definitive evidence of resident PKS genes in any dinoflagellate.

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No difference found in ribosomal DNA sequences from physiologically diverse clones of Karenia brevis (Dinophyceae) from the Gulf of Mexico

Cited by 47 publications

References 23 publications

Toxicity and nutritional inadequacy of Karenia brevis: synergistic mechanisms disrupt top-down grazer control

Toxicity and nutritional inadequacy of Karenia brevis: synergistic mechanisms disrupt top-down grazer control

Morphology and rDNA phylogeny of a Mediterranean <em>Coolia monotis</em> (Dinophyceae) strain from Greece

Localization of polyketide synthase encoding genes to the toxic dinoflagellate Karenia brevis

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