Some biochemical characteristics of toxic diatom Pseudo-nitzschia multiseries isolated in the Argentine Sea

Pseudo-nitzschia multiseries (Hasle) Hasle has been cited as an important component of the coastal marine phytoplankton in the Argentine Sea, but its capacity to produce domoic acid had not been proved yet. A culture of this species, isolated from waters of the Buenos Aires Province coastal region, allowed us to confirm its capacity to produce domoic acid. Other biochemical characteristics studied were, its pigment composition, and its content of mycosporine like aminoacids (MAA's). The cell content of domoic acid, estimated by HPLC was of 0.13 pg cel(-1). This value is similar to those reported for isolates of this species in other parts of the world ocean (0.1-21 pg cel(-1)). The pigment composition, determined by HPLC, showed a profile characteristic of diatoms with the accessory chlorophylls c(1) and c(2). This, seems to be distinctive for toxic species of the genus Pseudo-nitzschia, since non-toxic species of this genus posses also chlorophyll c(3). Another noteworthy biochemical characteristic is the production of several MAAs compounds, which have a photoprotective function against the stress induced by ultraviolet radiation. It is notorious in this species the presence of mycosporine-taurine, a rare MAAs only found previously in some marine anemona of the genus Anthopleura.