Flow cytometric determination of lipid content in a marine dinoflagellate, Crypthecodinium cohnii

Since flow cytometry allows rapid, simultaneous and quantitative measurements related to cell morphology and physiologicy, the lipid-specific fluorescent dye, Nile Red, was employed for the in vivo lipid quantification of Crypthecodinium cohnii, a heterotrophic marine dinoflagellate rich in polyunsaturated long chain fatty acids. The fluorescence signal was linearly correlated with the neutral and polar lipid content as determined by gravimetric techniques. A significant correlation of NR signal was also observed between the polar to neutral lipid ratio and docohexaenoic acid per cell. The results demonstrate a method for rapid lipid quantification that can be used in the selection, isolation and culture control of C cohnii clones with high lipid and DHA content.