Pigments and fatty acids of marine raphidophytes: A chemotaxonomic re-evaluation

Abstract

SUMMARY The patterns of occurrence of photosynthetic pigments and fatty acids among seven available species (11 strains) of marine raphidophytes were determined and used as chemotaxonomic markers. All currently recognized genera of marine raphidophytes were included for analysis: that is, Chattonella, Fibrocapsa, Heterosigma, Olisthodiscus and Haramonas. The characteristic pigment composition was shown to be chlorophyll a, chlorophylls c1 and/or c2, fucoxanthin as the major carot‐enoid, β,β‐carotene and any or all of zeaxanthin, violaxanthin and an auroxanthin‐like pigment as the minor carotenoids. The carotenoid composition of all marine raphidophyte genera investigated was virtually the same, except in Fibrocapsa and Haramonas, which differed due to the occurrence of fucoxanthinol and 19′‐butanoyloxyfucoxanthin, respectively. These fucoxanthin derivatives, in addition to fucoxanthin, have potential chemotaxonomic use for differentiating the two species. In all 11 strains, 15 fatty acids (saturated, mono‐unsaturated and polyunsaturated) were determined. Significant taxonomic distinctions between genera were reflected by their fatty acid profiles. A rapid key for the differentiation of genera, in addition to morphological features, may be the absence of the 18:4 fatty acid in Olisthodiscus; presence of 18:5 in Heterosigma; the presence of fucoxanthinol in Fibrocapsa and presence of 19′‐butanoyloxyfucoxanthin in Haramonas.

Phylogeny and morphology of a Chattonella (Raphidophyceae) species from the Mediterranean Sea: what is C. subsalsa?

“…This evidence tends to confirm the homogeneity of the pigment composition in marine raphidophytes and thereby excludes their use as species-specific markers (Mostaert et al, 1998;Mangoni et al, 2011).…”

“…Marine raphidophytes contain chlorophyll a, c 1 and/or c 2 , and diadinoxanthin, fucoxanthin and violaxanthin as the major carotenoids. There are also pigment variants, which can be restricted to particular genera; for example, Fibrocapsa and Haramonas species differ in the presence of fucoxanthinol in Fibrocapsa but 19-butanoyloxyfucoxanthin in Haramonas (Bjørnland & LiaaenJensen, 1989; Mostaert et al, 1998).…”

Seasonal variations in phytoplankton composition and transparent exopolymer particles in a eutrophicated coastal environment

“…Initial ratios for groups other than the raphidophytes used in the ChemTax calculation were derived after minor modifications following Mackey et al (1996) . Viola and Fuco were used as marker pigments for raphidophytes (Jeffrey et al 1997, Mostaert et al 1998) with respective ratios of 0.12 and 0.69 normalized to chl a. The taxonomic groups, marker pigments and initial ratios used for ChemTax analysis are presented in Table 1.…”

Freshwater Raphidophyceae from the State of Rio de Janeiro, Southeast Brazil

“…A large nucleus and numerous mucocysts or trichocysts are present (Heywood 1980, 1982, Mignot 1967. The freshwater species contain diadinoxanthin, heteroxanthin, and vaucheriaxanthin, and the majority of marine species contain fucoxanthin and violaxanthin (Mostaert et al 1998) (Yamaguchi et al 2009). The genus Chlorinimonas with a single species, C. sublosa Yamaguchi, Nakayama, Murakami & Inouye, has been described recently as a marine sand-dwelling raphydophycean; however, like the freshwater genera, it shows the presence of diadinoxanthine rather than fucoxathin (Yamaguchi et al 2009).…”