Carotenoids of clam, coral and nudibranch zooxanthellae in aposymbiotic culture

The carotenoids of unialgal cultures originating from symbiotic zooxanthellae of two molluscan (Tridacna crocea, a giant clam, and Pteraeolidia ianthine a nudibranch) and one cnidian (Pseudopterogorgia bipinnata, a gorgonian coral) host have been analysed by HPLC or TLC procedures combined with several spectroscopic techniques including MS and NMR. A high total carotenoid content (0.45-0.63% of the dry wt) was obtained. The carotenoid pattern with C37-norcarotenoids (peridinin and pyrrhoxanthin) comprising around 80% of total carotenoids, and β,β-carotene (2%), the ailenic dinoxanthin (3–4%) and the acetylenic diatoxanthin (1–3%) and diadinoxanthin (7–9%) representing minor C40-carotenoids, corresponds to that of peridinin-producing free-living dinoflagellates. Supplementary 1H NMR and 13C NMR data are reported for peridinin and pyrrhoxanthin. A polar, minor carotenoid, P447, was partly characterized as containing a disaccharide glycosidically bound to an allenic carotenoid aglycone. Re-evaluation of previous reports suggests the wide-spread occurrence of related carotenoid disaccharides in Dinophyceae for which they are considered a new chemosystematic marker.