IDENTIFICATION, GROWTH AND TOXICITY OF SINGAPORE BENTHIC PROROCENTRUM (DINOPHYCEAE)

Abstract

Prorocentrum is a genus of dinoflagellate whose members possess two flagella and a cell covering called a theca. Typically, these organisms which are neither plants, animals or fungi, appear laterally compressed and live in marine and fresh waters. Over the years, many new species have been found and efforts have been made to differentiate them based on several morphological characteristics. Several species produce toxins that are transferred to humans who eat contaminated shellfish. Okadaic acid (OA) and dinophysisitoxin-1 (DTX -1) are toxins which have often been implicated in diarrhetic shellfish poisoning (DSP) worldwide. This project studied Prorocentrum from Pulau Hantu and Sultan Shoals. Based on morphological characteristics, the Prorocentrum from Pulau Hantu was positively identified as Prorocentrum lima. Samples from cultures were taken at two-day intervals for cell counts and toxin analysis. The cell counts allowed growth curves to be plotted and it was found that the growth patterns of Prorocentrum from Sultan Shoals and Pulau Hantu were similar. Using the mass spectrometer, presence and concentration of OA and DTX-1 were tested at four points of the growth curves. Although DTX-1 was not detected, average OA concentration per cell was found to fluctuate at these four points, reaching maximum on day 20.