Comparative Study Of Dinophysis Fortii In The Coastal Waters Of Dalian And Dinophysis Acuminata Of The United States

Diarrhetic shellfish poisoning(DSP) mainly included okadaic acid(OA), dinophysistoxins(DTXs), pectenotoxins(PTXs) and its derivatives. Dinophysis were the main source of DSP and widely distributed around the world as well as the coastal waters of China. DSP contaminated shellfish had been frequently detected, which should be paid more attention by relevant administrative agencies. The present works studied a Dinophysis that isolated from the costal waters of Dalian and ananlysed the one from America by contrast. Taxonomic characteristics were described by morphology and molecular biology. LC-MS methods were established to analyze the toxin composition and production.From morphology, the cell from Dalian measured 53.8±2.0 μm in lengh and 39.3±2.1 μm in width; the cell from America measured 37.3±2.1 μm in lengh and 24.8±2.1 μm in width. The strain from Dalian were definitively identified as Dinophysis fortii, the strain of the United States were identified as Dinophysis acuminata complex by morphological and molecular methods.The growth of the strain from Dalian was influenced by temperature and it had the maximum growth rate at 22℃. The cell toxin content of OA, DTX1, PTX2 varied significantly with growth phase at different temperatures. The result showed the average content of OA, DTX1, PTX2 were 10.38~35.58 pg/cell、8.49~43.56 pg/cell and 91.18~171.16 pg/cell. The toxin contents were higher at 8℃ than the other two temperatures(15℃ and 22℃). The growth of D.fortii played a significant role in its toxin production, the toxin content in each cell increased when the cell density reduced.The strain of the United States had the same toxin component with the strain from Dalian, but its toxin contents were lower than the strain from Dalian. Its maximum growth rate appeared at 15℃.In summary, D.fortii is the source of OA, DTX1 and PTX2 in the coastal waters of Dalian. The growth of the strain and its toxin production were influenced by temperature. The present study was first focus on biology and ecology of D.fortii in Dalian. These results provided referenced methods for the monitor and toxin of D.fortii to reasonably establish monitoring and forecast strategy, and reduce the loss which D.fortii generated.