Comparative analyses of carotenoid pigments in Euglena gracilis and Astasia pertyi (Euglenophyta) by reversed phase-high performance liquid chromatography

Examination of the carotenoid composition of light-grown and etiolated (dark-grown) Euqlena gracilis var. bacillaris by reversed phase-high performance liquid chromatography has shown that these organisms have a similar complement of pigments, although there are quantitative differences. Etiolated cells have a much reduced total pigment concentration; however, with respect to individual carotenoids, some are drastically reduced, others are reduced to a lesser degree, and still others exhibit a slight increase when compared to light-grown cells. The previously reported absence of chlorophyll in etiolated cells is questionable, as this work shows that ca. 4% is being maintained in this cell line. Preliminary results from Astasia pertyi, examined here for the first time, indicate a carotenoid complement quite different from that of Euglena gracilis. The comparative results from Astasia pertyi and Euglena gracilis light-grown and etiolated cells may have implications both for the biosynthetic patterns of carotenoids and phylogenetic considerations in the euglenoid flagellates; the techniques developed here should provide a strong basis on which to develop taxonomies based on carotenoid composition.