Fig. 2

Identification and quantitative illustration of CPEs and other chlorophyll derivatives. Left: Three-dimensional (3D) HPLC chromatograms of extracts of a an aged unialgal culture of a euglenophyte (Eutreptiella sp. CCMP389); and b a two-membered co-culture of a algivorous stramenopile (Actinophris sol) fed a dietary green alga (Chlorogonium capillatum); c HPLC online visible absorption spectra of major chlorophylls and their derivatives; d 3D HPLC chromatogram of an extract of C. capillatum only (an unialgal culture). Right: e Donut charts showing the relative abundances of the derivatives of chlorophyll a (Chl-a) in representative cultures in which CPEs were detected. These included 13²,17³-cyclopheophorbide a enol (cPPB-aE) and other miscellaneous derivatives: (13²R/S)-hydroxychlorophyllone a (hCPL-a), other cPPB-aE derivatives (pyropheophytin a and compound-X_a; Supplementary Fig. S1), pheophytin a (Phe-a), Mg-chelated derivatives of Chl-a (Chl-a allomers and chlorophyllide a), and free-base derivatives of Chl-a (pheophorbide a and pyropheophorbide a). Species names in parentheses indicate the dietary algae in two-membered co-cultures. Numerals in each doughnut chart indicate the ratio of the plotted derivative to the total Chl-a derivatives (the plotted derivatives plus intact Chl-a) in each analysis as a percentage. Therefore, 100 indicates the complete alteration of the originally produced Chl-a