Permalink : http://hdl.handle.net/2115/38469

KEYWORDS : Autotrophic dinoflagellate;Heterotrophic dinoflagellate;Resting cyst;4α-Methyl sterol

Four motile cells of autotrophic dinoflagellates, Peridinium umbonatum var. inaequale, Akashiwo sanguinea, Scrippsiella tinctoria, and Prorocentrum micans, commonly contain five major sterols: cholesterol, 4-methylcholestan-3-ol, 4, 24-dimethylcholestan-3-ol, dinosterol and dinostanol. A motile cell of heterotrophic dinoflagellate, Protoperidinium crassipes, contains cholesterol, 4, 24- dimethylcholestan-3-ol, dinosterol, dinostanol and 4-tetramethylcholestan-3-ol as major free sterols. Dinosterol concentration of heterotrophic dinoflagellate is about 4-12 times higher than those of autotrophic species, suggesting that the heterotrophic dinoflagellate is important source of dinosterol in some sediments. 4-Methylcholestan-3-ol and 4-tetramethylcholestan-3-ol occur respectively in autotrophic and heterotrophic dinoflagellates are believed to serve as potential biomarkers in respective types. Resting cyst of P. inaequale contains 4-methylcholestan-3β-ol, 4, 24-dimethyl-5α-cholestan-3β-ol, dinosterol, dinostanol, and unknown C31 sterol as major free sterols. The unknown C31 sterol detected only in resting cyst could have been produced during resting stage. This compound may serve as a potential biomarker for resting cysts of dinoflagellate.