Copepods induce paralytic shellfish toxin production in marine dinoflagellates

Selander, Erik; Thor, Peter; Toth, Gunilla B.; Pavia, Henrik

doi:10.1098/rspb.2006.3502

Cited by 182 publications

(233 citation statements)

References 48 publications

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“…(Selander et al, 2006), but the full induction takes 2-4 days (Selander et al, 2012), and is low with the low concentration of copepods used here (1 per 800 ml). Thus, it is assumed that the chemical profile of cells from the culture is representative for the experiments.…”

Section: Copepod Feeding Behaviormentioning

confidence: 88%

“…Most previous studies of the response of copepods to toxic algae are incubation studies, in which the net outcome of the copepod-prey interaction is quantified in terms of feeding rate, prey selection, growth or egg production rate, or other similar bulk measures (reviewed by Turner, 2014). The direct video observation of individual responses and of direct copepod-prey cell interactions provided by this and a few other studies (Bruno et al, 2012;Hong et al, 2012;Tiselius et al, 2013) Selander et al, 2006;Teegarden, 1999). The fact that the copepods can distinguish between cells of very similar size and shape suggests that selection is mediated by chemical information.…”

Section: Repertoire Of Copepod Feeding Behaviors and Implications To mentioning

confidence: 95%

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Distinctly different behavioral responses of a copepod, Temora longicornis , to different strains of toxic dinoflagellates, Alexandrium spp.

Hansen

Nielsen

et al. 2017

Harmful Algae

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A B S T R A C TZooplankton responses to toxic algae are highly variable, even towards taxonomically closely related species or different strains of the same species. Here, the individual level feeding behavior of a copepod, Temora longicornis, was examined which offered 4 similarly sized strains of toxic dinoflagellate Alexandrium spp. and a non-toxic control strain of the dinoflagellate Protoceratium reticulatum. The strains varied in their cellular toxin concentration and composition and in lytic activity. High-speed video observations revealed four distinctly different strain-specific feeding responses of the copepod during 4 h incubations: (i) the 'normal' feeding behavior, in which the feeding appendages were beating almost constantly to produce a feeding current and most (90%) of the captured algae were ingested; (ii) the beating activity of the feeding appendages was reduced by ca. 80% during the initial 60 min of exposure, after which very few algae were captured and ingested; (iii) capture and ingestion rates remained high, but ingested cells were regurgitated; and (iv) the copepod continued beating its appendages and captured cells at a high rate, but after 60 min, most captured cells were rejected. The various prey aversion responses observed may have very different implications to the prey and their ability to form blooms: consumed but regurgitated cells are dead, captured but rejected cells survive and may give the prey a competitive advantage, while reduced feeding activity of the grazer may be equally beneficial to the prey and its competitors. These behaviors were not related to lytic activity or overall paralytic shellfish toxins (PSTs) content and composition and suggest that other cues are responsible for the responses.

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Section: Copepod Feeding Behaviormentioning

confidence: 88%

Section: Repertoire Of Copepod Feeding Behaviors and Implications To mentioning

confidence: 95%

Distinctly different behavioral responses of a copepod, Temora longicornis , to different strains of toxic dinoflagellates, Alexandrium spp.

Hansen

Nielsen

et al. 2017

Harmful Algae

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“…The cellular toxin quota appears to increase upon phosphorus limitation and decrease upon nitrogen limitation (van de Waal et al, 2014). One factor that has been found to lead to a several fold increase in cellular toxin quota is the presence of copepods and their waterborne cues (Selander et al, 2006;Wohlrab et al, 2010;Yang et al, 2011).…”

Section: Introductionmentioning

confidence: 99%

Gene duplication, loss and selection in the evolution of saxitoxin biosynthesis in alveolates

Murray

Diwan

Orr

et al. 2015

Molecular Phylogenetics and Evolution

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a b s t r a c tA group of marine dinoflagellates (Alveolata, Eukaryota), consisting of $10 species of the genus Alexandrium, Gymnodinium catenatum and Pyrodinium bahamense, produce the toxin saxitoxin and its analogues (STX), which can accumulate in shellfish, leading to ecosystem and human health impacts. The genes, sxt, putatively involved in STX biosynthesis, have recently been identified, however, the evolution of these genes within dinoflagellates is not clear. There are two reasons for this: uncertainty over the phylogeny of dinoflagellates; and that the sxt genes of many species of Alexandrium and other dinoflagellate genera are not known. Here, we determined the phylogeny of STX-producing and other dinoflagellates based on a concatenated eight-gene alignment. We determined the presence, diversity and phylogeny of sxtA, domains A1 and A4 and sxtG in 52 strains of Alexandrium, and a further 43 species of dinoflagellates and thirteen other alveolates. We confirmed the presence and high sequence conservation of sxtA, domain A4, in 40 strains (35 Alexandrium, 1 Pyrodinium, 4 Gymnodinium) of 8 species of STX-producing dinoflagellates, and absence from non-producing species. We found three paralogs of sxtA, domain A1, and a widespread distribution of sxtA1 in non-STX producing dinoflagellates, indicating duplication events in the evolution of this gene. One paralog, clade 2, of sxtA1 may be particularly related to STX biosynthesis. Similarly, sxtG appears to be generally restricted to STX-producing species, while three amidinotransferase gene paralogs were found in dinoflagellates. We investigated the role of positive (diversifying) selection following duplication in sxtA1 and sxtG, and found negative selection in clades of sxtG and sxtA1, clade 2, suggesting they were functionally constrained. Significant episodic diversifying selection was found in some strains in clade 3 of sxtA1, a clade that may not be involved in STX biosynthesis, indicating pressure for diversification of function.

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“…the defense mechanism is inducible. Selander et al (2006) found that waterborne cues from the copepod Acartia tonsa induced paralytic shellfish poisoning toxin (PST) production in the dinoflagellate Alexandrium minutum, which led to reduced grazing of A. tonsa on A. minutum. It has also been shown that the chemical and morphological responses may take place simultaneously .…”

Section: Introductionmentioning

confidence: 99%

Induction of domoic acid production in the toxic diatom Pseudo-nitzschia seriata by calanoid copepods

et al. 2015

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a b s t r a c tThe toxic diatom Pseudo-nitzschia seriata was exposed directly and indirectly (separated by a membrane) to copepods, Calanus hyperboreus and C. finmarchicus, to evaluate the effects of the copepods on domoic acid production and chain formation in P. seriata. The toxicity of P. seriata increased in the presence of the copepods. This response was chemically mediated without physical contact between the organisms suggesting that it was induced by potential waterborne cues from the copepods or changes in water chemistry. Domoic acid production may be related to defense against grazing in P. seriata although it was not shown in the present study. To evaluate if the induction of domoic acid production was mediated by the chemical cues from damaged P. seriata cells, live P. seriata cells were exposed to a P. seriata cell homogenate, but no effect was observed. Chain formation in P. seriata was affected only when in direct contact with the copepods. This study suggests that the presence of zooplankton may be one of the factors affecting the toxicity of Pseudo-nitzschia blooms in the field.

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Copepods induce paralytic shellfish toxin production in marine dinoflagellates

Cited by 182 publications

References 48 publications

Distinctly different behavioral responses of a copepod, Temora longicornis , to different strains of toxic dinoflagellates, Alexandrium spp.

Distinctly different behavioral responses of a copepod, Temora longicornis , to different strains of toxic dinoflagellates, Alexandrium spp.

Gene duplication, loss and selection in the evolution of saxitoxin biosynthesis in alveolates

Induction of domoic acid production in the toxic diatom Pseudo-nitzschia seriata by calanoid copepods

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