Toxicity of four potentially ichthyotoxic marine phytoflagellates determined by four different test methods

Abstract

The toxicity of the marine phytoflagellates Prymnesium parvum. Prymnesium patelliferum, Chrysochromulina polylepis, and Chrysochromulina leadbeateri isolated from ichthyotoxic blooms in Norwegian coastal waters was compared using four different test methods developed for the detection of toxins produced by these species. The test methods were (1) lethality to the crustacean Artemia salina exposed to living algae, (2) hemolytic activity (lysis of human erythrocytes) by crude algal lipid extracts, and inhibition of the uptake of the neurotransmitters L-glutamate and gamma-aminobutyric acid (GABA) into (3) synaptosomes and (4) synaptic vesicles of rat brain by crude algal lipid extracts. All test methods indicated different levels of toxicity among the algal species. Prymnesium parvum, P. patelliferum, and C. polylepis were toxic as determined by all four test methods. The cultured strain of C. leadbeateri, although isolated from a toxic algal bloom, appeared nontoxic by the methods used here, and served as a negative control. The hemolytic activity of P. parvum extract was about nine times higher than that of P. patelliferum extract, whereas the activity was only two to three times higher using the other three methods. Chrysochromulina polylepis had higher toxic activity than P. patelliferum except for less inhibitory effect on synaptosomes. The inhibition of synaptosomal and vesicular neurotransmitter uptake systems by extracts of P. parvum, P. patelliferum, and C. polylepis appeared to be due to similar mechanisms of action, since similar inhibition ratios between the uptake of L-glutamate and GABA were obtained in both synaptosomes and synaptic vesicles. We suggest that P. parvum, P. patelliferum, and C. polylepis produce a set of similar toxins and that the relative amounts of each toxin vary among the three species.

Effects of the toxic haptophyte Prymnesium parvum on the survival and feeding of a ciliate: the influence of different nutrient conditions

“…Previous studies have shown that limiting conditions of either nitrogen or phosphorus enhance the toxic effect of Prymnesium parvum (Shilo 1971, Meldahl et al 1994, Johansson & Granéli 1999, suggesting that toxin production is a defence mechanism used to improve the competitive ability of P. parvum under conditions of severe nutrient competition. In the present study we investigated the survival and feeding of the ciliate Euplotes affinis, when exposed to mixed cultures of P. parvum and Rhodomonas cf.…”

Phagotrophy and toxicity variation in the mixotrophic Prymnesium patelliferum (Haptophyceae)

“…In Prymnesium spp., laboratory experiments indicate that toxin production is enhanced under nutrient stress irrespective of which nutrient (N, P) is limiting growth (Johansson and Granéli 1999). Phosphorus limitation stimulates the toxicity of P. patelliferum compared to nutrient-replete conditions (Larsen et al 1993;Meldahl et al 1994;this study). Because N and P are minor elements in the composition of the toxin complex (e.g., prymnesins) found in ichthyotoxic haptophytes (Igarashi et al 1996), it has been hypothesized that the toxicity in haptophytes such as Chrysochromulina and Prymnesium spp.…”

“…(Edvardsen and Paasche 1998). Nutrient availability seems to be an important regulation factor for the production of different types of algal toxins (Anderson et al 1990;Bates et al 1991;McLachlan et al 1994;Meldahl et al 1994;Johansson and Granéli 1999). In Prymnesium spp., laboratory experiments indicate that toxin production is enhanced under nutrient stress irrespective of which nutrient (N, P) is limiting growth (Johansson and Granéli 1999).…”

Harmful Algal Blooms: Physiology, Behavior, Population Dynamics and Global Impacts- A Review

“…Other plankton organisms were also shown to be affected by this Chrysochromulina bloom (Nielsen et al 1990). Chrysochromulina leadbeatri caused mortalities in caged salmon among the northern Norwegian coast in 1991 and the two Prymnesium (P. patelliferum and P. parvum) have also caused mortalities in aquaculture facilities for salmon and rainbow trout (Aune et al 1992;Meldahl et al 1994Meldahl et al , 1995.…”