Chlorophyll c2 monogalactosyldiacylglyceride ester (chl c2-MGDG). A novel marker pigment for Chrysochromulina species (Haptophyta)

The pigment composition of the haptophyte Chrysochromulina polylepis (Strain CCMP 286) was analysed by high-performance liquid chromatography (HPLC) using pyridine-containing mobile phases and polymeric C 18 , or monomeric C 8 columns. The polar chlorophyll (chl) c pigment composition included chl c 2 and chl c 3 as major fractions, and divinyl protochlorophyllide a (DV pchlide or MgDVP) as a minor component. Several non-polar fluorescent peaks sharing a common chl c-type absorption spectrum were also detected. The main component of these peaks was isolated and characterised by chromatographic behaviour, UV-visible (UV-VIS) and fluorescence spectroscopy. Although spectral properties were similar to a high molecular weight non-polar chl c (1313 Da) recently characterised from Emiliania huxleyi, both chlorophylls showed different chromatographic behaviour. Fast atom bombardment-mass spectrometry (FAB-MS) analysis showed a high mass molecular ion (m/z 1265), and a fragmentation pattern compatible with a molecular structure consisting of a chl c 2 pigment linked by an ester bond to the sugar moiety of a monogalactosyl diacylglyceride (MGDG), which included 2 myristic acid (14:0) residues. To study the distribution pattern of the novel pigment, different strains of C. polylepis and other species of the genus Chrysochromulina were analysed. A similar chl c 2 ester was also present in 2 C. polylepis strains (K, B11) and in C. aff. polylepis (PLY 200), as well as in C. acantha, C. camella, C. leadbeateri, C. strobilus, C. throndsenii,. Three species, C. fragaria, C. hirta (2 strains) and C. kappa, lacked the new chl c, but they contained detectable amounts of other nonpolar chl c-like pigments. The feasibility of using chls c and carotenoids as marker pigments to detect Chrysochromulina species in field samples is discussed.