Intracellular domoic acid production in Pseudo-nitzschia multistriata isolated from the Gulf of Naples (Tyrrhenian Sea, Italy)

Twenty-six Pseudo-nitzschia multistriata cultures were tested for intracellular domoic acid production and fourteen were found to be toxic. Four suboptimal growth conditions were compared with conditions observed to be optimal to explore possible triggers for intracellular domoic acid production. Silica- and phosphate-limitation and low light treatment induced elevated toxin concentrations whereas high temperature appeared to suppress it. Inheritance of the toxin-production ability was investigated by measuring intracellular toxin content in a total of thirty-nine F1 strains from two different crosses. Results showed radical differences in domoic acid levels among the F1 offspring from the same parents.