Changes in toxin content, biomass and pigments of the dinoflagellate Alexandrium minutum during nitrogen refeeding and growth into nitrogen or phosphorus stress
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AuthorsFlynn, K. (Krystyna); Franco, J.M. (José Mariano); Fernández, P. (Pablo); Reguera, B. (Beatriz); Zapata, M. (Manuel); Wood, G. (Gareth); Flynn, K.J. (Kevin)
Paralytic shellfish poisons
Algal growth dynamics
Two strains oi the paralytic shellfish toxin (PST) producing dinoflagellate Alexandrium minutum Halim (highly toxic ALl V and weakly toxic AL2V) were grown in batch culture with either nitrate or phosphate as the limiting nutrient. In comparison with cells of the strain AL1V, cells of AL2V grew at a similar C-specific Tale, had a higher C/N ratio, and lower ratios of chl a/chl C2and chl a/peridinin. Neither chlorophylls flor carotenoids could be used to estimate C-biomass, N-biomass or toxin content for this organismo The toxin profile for both strains was dominated (up to 95 %) by the gonyautoxin GTX4, with smaller proportions of GTX1, GTX2 and GTX3. The Tale of toxin synthesis for both strains was greatest 1 to 2 d after the N-refeeding of N-deprived cells, with the net Tale of toxin syn- .thesis exceeding that of C-biomass and cell division by a factor of up to 4. Toxin synthesis was not enhanced by short-term P-stress. N-stress alone led to a decrease in toxin cell-I, but ...