A dinoflagellate producer of pinnatoxin G, isolated from sub-tropical Japanese waters

A thecate dinoflagellate (Peridiniales, Dinophyceae) was cultured from individual non-calcareous cysts, isolated from surface sediment samples collected in Okinawa, Japan. Two isolates (CAWD188 and CAWD190) from two different sampling sites, each cultured from an individual cyst, produced ca. 11.9 and 15 pg cell−1 pinnatoxin G, respectively, as determined by liquid chromatography-mass spectrometric (LC-MS). No other pinnatoxins were detected. The motile cells and cysts appeared morphologically identical to those of pinnatoxins E and F producers isolated from New Zealand waters and pinnatoxins E, F, and G producers isolated from Australian waters. Motile and cysts cells measured an average of 25 μm long × 21.3 μm wide and 29 μm long × 25.5 μm wide, respectively. Analysis of the large subunit ribosomal DNA sequence data showed two well supported strains with slight differences between the Japanese and the Australasian isolates.