A multi-phylum study of grazer-induced paralytic shellfish toxin production in the dinoflagellate Alexandrium fundyense: A new perspective on control of algal toxicity

Senft-Batoh, Christina; Dam, Hans G.; Shumway, Sandra E.; Wikfors, Gary H.

doi:10.1016/j.hal.2015.02.008

Cited by 24 publications

(17 citation statements)

References 72 publications

(109 reference statements)

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“…This suggests that genotype-specific interactions and associated trait variation within a population maintain disequilibrium among genotypes and can, therefore, among other mechanisms, explain the 'paradox of the plankton'. The presence of paralytic shellfish poisoning toxins appears to have a negligible or neutral effect with respect to the species interactions investigated here (Senft-Batoh et al, 2015).…”

Section: Discussionmentioning

confidence: 68%

Trait changes induced by species interactions in two phenotypically distinct strains of a marine dinoflagellate

et al. 2016

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Populations of the toxigenic marine dinoflagellate Alexandrium are composed of multiple genotypes that display phenotypic variation for traits known to influence top-down processes, such as the ability to lyse co-occurring competitors and prospective grazers. We performed a detailed molecular analysis of species interactions to determine how different genotypes perceive and respond to other species. In a controlled laboratory culture study, we exposed two A. fundyense strains that differ in their capacity to produce lytic compounds to the dinoflagellate grazer Polykrikos kofoidii, and analyzed transcriptomic changes during this interaction. Approximately 5% of all analyzed genes were differentially expressed between the two Alexandrium strains under control conditions (without grazer presence) with fold-change differences that were proportionally higher than those observed in grazer treatments. Species interactions led to the genotype-specific expression of genes involved in endocytotic processes, cell cycle control and outer membrane properties, and signal transduction and gene expression regulatory processes followed similar patterns for both genotypes. The genotype-specific trait changes observed in this study exemplify the complex responses to chemically mediated species interactions within the plankton and their regulation at the gene level.

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Section: Discussionmentioning

confidence: 68%

Trait changes induced by species interactions in two phenotypically distinct strains of a marine dinoflagellate

et al. 2016

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“…Finally, we recall that our model only describes the relationship between nutrients (throughout the cellular nutritional status) and toxin production, and it does not account for other biotic processes, such as grazing, which can also stimulate toxin production in dinoflagellates [ 73 , 74 ]. These factors are important to fully understand the environmental regulation of toxin production and should be considered in future model developments meant to simulate algal toxicity in a realistic ecosystem framework.…”

Section: Discussionmentioning

confidence: 99%

Modelling the Stoichiometric Regulation of C-Rich Toxins in Marine Dinoflagellates

et al. 2015

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Toxin production in marine microalgae was previously shown to be tightly coupled with cellular stoichiometry. The highest values of cellular toxin are in fact mainly associated with a high carbon to nutrient cellular ratio. In particular, the cellular accumulation of C-rich toxins (i.e., with C:N > 6.6) can be stimulated by both N and P deficiency. Dinoflagellates are the main producers of C-rich toxins and may represent a serious threat for human health and the marine ecosystem. As such, the development of a numerical model able to predict how toxin production is stimulated by nutrient supply/deficiency is of primary utility for both scientific and management purposes. In this work we have developed a mechanistic model describing the stoichiometric regulation of C-rich toxins in marine dinoflagellates. To this purpose, a new formulation describing toxin production and fate was embedded in the European Regional Seas Ecosystem Model (ERSEM), here simplified to describe a monospecific batch culture. Toxin production was assumed to be composed by two distinct additive terms; the first is a constant fraction of algal production and is assumed to take place at any physiological conditions. The second term is assumed to be dependent on algal biomass and to be stimulated by internal nutrient deficiency. By using these assumptions, the model reproduced the concentrations and temporal evolution of toxins observed in cultures of Ostreopsis cf. ovata, a benthic/epiphytic dinoflagellate producing C-rich toxins named ovatoxins. The analysis of simulations and their comparison with experimental data provided a conceptual model linking toxin production and nutritional status in this species. The model was also qualitatively validated by using independent literature data, and the results indicate that our formulation can be also used to simulate toxin dynamics in other dinoflagellates. Our model represents an important step towards the simulation and prediction of marine algal toxicity.

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“…This interpretation is supported by the observations that algal toxins often have a deterrent rather than a toxic effect on grazers [10][11][12][13][14][15], and that toxin production may be upregulated in the presence of grazers or their cues, as demonstrated in dinoflagellates, Alexandrium spp. [13,16,17], and in diatoms, Pseudo-nitzschia spp. [18].…”

Section: Introductionmentioning

confidence: 99%

The cost of toxin production in phytoplankton: the case of PST producing dinoflagellates

et al. 2018

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Many species of phytoplankton produce toxins that may provide protection from grazing. In that case one would expect toxin production to be costly; else all species would evolve toxicity. However, experiments have consistently failed to show any costs. Here, we show that costs of toxin production are environment dependent but can be high. We develop a fitness optimization model to estimate rate, costs, and benefits of toxin production, using PST (paralytic shellfish toxin) producing dinoflagellates as an example. Costs include energy and material (nitrogen) costs estimated from well-established biochemistry of PSTs, and benefits are estimated from relationship between toxin content and grazing mortality. The model reproduces all known features of PST production: inducibility in the presence of grazer cues, low toxicity of nitrogen-starved cells, but high toxicity of P-limited and light-limited cells. The model predicts negligible reduction in cell division rate in nitrogen replete cells, consistent with observations, but >20% reduction when nitrogen is limiting and abundance of grazers high. Such situation is characteristic of coastal and oceanic waters during summer when blooms of toxic algae typically develop. The investment in defense is warranted, since the net growth rate is always higher in defended than in undefended cells.

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A multi-phylum study of grazer-induced paralytic shellfish toxin production in the dinoflagellate Alexandrium fundyense: A new perspective on control of algal toxicity

Cited by 24 publications

References 72 publications

Trait changes induced by species interactions in two phenotypically distinct strains of a marine dinoflagellate

Trait changes induced by species interactions in two phenotypically distinct strains of a marine dinoflagellate

Modelling the Stoichiometric Regulation of C-Rich Toxins in Marine Dinoflagellates

The cost of toxin production in phytoplankton: the case of PST producing dinoflagellates

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