17 pages, 5 figures, 2 tables.A high-performance liquid chromatographic (HPLC) method based on a reversed-phase C8 column and pyridine-containing mobile phases was developed for the simultaneous separation of chlorophylls and carotenoids. The method is selective enough to resolve monovinyl (MV) and divinyl (DV) pairs of polar chlorophylls and DV chlorophyll a (chl a) (the marker pigment for the prokaryote Prochlorococcus marinus) from chl a (the MV analogue). Only the pair DV chl a/chl b was not resolved. This resolution capability for chlorophylls was only previously achieved using polymeric C18 columns in combination with ammonium acetate or pyridine-containing mobile phases. The proposed method also allows the separation of taxon-specific carotenoids belonging to 8 algal classes, including some critical pigment pairs for previous HPLC methods using C18 columns. The method employs a binary gradient, so it can be used with both low-pressure and high-pressure mixing instruments. Method transferability was tested using 3 HPLC systems. Only a slight adjustment of gradient profile was required to obtain similar results with HPLC equipment having different dwell volumes. The selectivity of the method towards some recently discovered chlorophyll and carotenoid pigments makes it especially suitable for studying not only field samples, but also for re-examining the pigment composition of different algal classes.This work was supported by the project\ud PGIDT-CIMA-99/9 of the Xunta de Galicia, Spain.Peer reviewe

Several Dinophysis species produce diarrhoetic toxins (okadaic acid and dinophysistoxins) and pectenotoxins, and cause gastointestinal illness, Diarrhetic Shellfish Poisoning (DSP), even at low cell densities (<10³ cells·L⁻¹). They are the main threat, in terms of days of harvesting bans, to aquaculture in Northern Japan, Chile, and Europe. Toxicity and toxin profiles are very variable, more between strains than species. The distribution of DSP events mirrors that of shellfish production areas that have implemented toxin regulations, otherwise misinterpreted as bacterial or viral contamination. Field observations and laboratory experiments have shown that most of the toxins produced by Dinophysis are released into the medium, raising questions about the ecological role of extracelular toxins and their potential uptake by shellfish. Shellfish contamination results from a complex balance between food selection, adsorption, species-specific enzymatic transformations, and allometric processes. Highest risk areas are those combining Dinophysis strains with high cell content of okadaates, aquaculture with predominance of mytilids (good accumulators of toxins), and consumers who frequently include mussels in their diet. Regions including pectenotoxins in their regulated phycotoxins will suffer from much longer harvesting bans and from disloyal competition with production areas where these toxins have been deregulated.

20 pages, 5 figures, 11 tables.The pigment compositions of 37 species (65 strains) of cultured haptophytes were analysed using improved HPLC methods. We distinguished 8 pigment types based on the distribution of 9 chlorophyll c (chl c) pigments and 5 fucoxanthin derivatives. All types contained chl c2 and Mg-2,4-divinyl phaeoporphyrin a5 monomethyl ester (MgDVP), fucoxanthin, diadinoxanthin and β,β-carotene. Pigment types were based on the following additional pigments: Type 1: chl c1; Type 2: chl c1 and chl c2-Pavlova gyrans-type; Type 3: chl c1 and chl c2-monogalactosyl diacylglyceride ester (chl c2-MGDG [18:4/14:0]); Type 4: chl c1, chl c3 and non-polar chl c1-like; Type 5: chl c1, chl c3, chl c2-MGDG [18:4/14:0] and 4-keto-fucoxanthin; Type 6: chl c3, monovinyl chl c3 (MV-chl c3), chl c2-MGDG [18:4/14:0], 19¹-hexanoyloxyfucoxanthin and its 4-keto derivative, and traces of 19¹-butanoyloxyfucoxanthin; Type 7: similar to Type 6, minus MV-chl c3 but with chl c2-MGDG [14:0/14:0] added; Type 8: similar to Type 6, minus MV-chl c3 but with significant 19¹-butanoyloxyfucoxanthin. Taxonomic associations ranged from single genera to multiple families - Type 1: Pavlovaceae, Isochrysidaceae and Pleurochrysidaceae; Type 2: Pavlovaceae; Type 3: Isochrysidaceae; Type 4: Prymnesium spp.; Type 5: Ochrosphaera spp.; Type 6: Nöelaerhabdaceae, notably Emiliania spp.; Type 7: Chrysochromulina spp.; Type 8: Phaeocystaceae, Prymnesiaceae and Isochrysidaceae. These pigment types showed a strong correlation with available phylogenetic trees, supporting a genetic basis for the pigment associations. The additional marker pigments offer oceanographers greater power for detecting haptophytes in mixed populations, while also distinguishing a greater proportion of them from diatoms.Peer reviewe

Summary: The importance of the cyanobacteria Prochlorococcus and Synechococcus in marine ecosystems in terms of abundance and primary production can be partially explained by ecotypic differentiation. Despite the dominance of eukaryotes within photosynthetic picoplankton in many areas a similar differentiation has never been evidenced for these organisms. Here we report distinct genetic [rDNA 18S and internal transcribed spacer (ITS) sequencing], karyotypic (pulsed‐field gel electrophoresis), phenotypic (pigment composition) and physiological (light‐limited growth rates) traits in 12 Ostreococcus strains (Prasinophyceae) isolated from various marine environments and depths, which suggest that the concept of ecotype could also be valid for eukaryotes. Internal transcribed spacer phylogeny grouped together four deep strains isolated between 90 m and 120 m depth from different geographical origins. Three deep strains displayed larger chromosomal bands, different chromosome hybridization patterns, and an additional chlorophyll (chl) c ‐like pigment. Furthermore, growth rates of deep strains show severe photo‐inhibition at high light intensities, while surface strains do not grow at the lowest light intensities. These features strongly suggest distinct adaptation to environmental conditions encountered at surface and the bottom of the oceanic euphotic zone, reminiscent of that described in prokaryotes.

20 páginas, 3 figuras, 6 tablasMost photosynthetic dinoflagellates contain a chloroplast with peridinin as the major carotenoid. Chloroplasts from other algal lineages have been reported, suggesting multiple plastid losses and replacements through endosymbiotic events. The pigment composition of 64 dinoflagellate species (122 strains) was analysed by using high-performance liquid chromatography. In addition to chlorophyll (chl) a, both chl c2 and divinyl protochlorophyllide occurred in chl c-containing species. Chl c1 co-occurred with chl c2 in some peridinin-containing (e.g. Gambierdiscus spp.) and fucoxanthin-containing dinoflagellates (e.g. Kryptoperidinium foliaceum). Chl c3 occurred in dinoflagellates whose plastids contained 19’-acyloxyfucoxanthins (e.g. Karenia mikimotoi). Chl b was present in green dinoflagellates (Lepidodinium chlorophorum). Based on unique combinations of chlorophylls and carotenoids, 6 pigment-based chloroplast types were defined: Type 1: peridinin/dinoxanthin/chl c2 (Alexandrium minutum); Type 2: fucoxanthin/19’-acyloxy fucoxanthins/4-keto-19’-acyloxy-fucoxanthins/gyroxanthin diesters/chl c2, c3, monogalactosyl-diacylglycerol-chl c2 (Karenia mikimotoi); Type 3: fucoxanthin/19’-acyloxyfucoxanthins/gyroxanthin diesters/chl c2, c3 (Karlodinium veneficum); Type 4: fucoxanthin/chl c1, c2 (K. foliaceum); Type 5: alloxanthin/chl c2/phycobiliproteins (Dinophysis tripos); Type 6: neoxanthin/violaxanthin/a major unknown carotenoid/chl b (Lepidodinium chlorophorum). While plastids with peridinin, and probably those with chl b, originated by secondary endosymbiosis, the other chloroplast types were obtained through tertiary endosymbiosis. Chloroplast types corresponded with evolutionary lineages within dinoflagellates. Caution must be observed when only peridinin is used for tracking photosynthetic dinoflagellates in field samples. The additional marker pigments offer oceanographers greater power for detecting dinophytes in mixed populations.This work was supported by funds\ud from the Xunta de Galicia, Spain (PGIDIT-06 PXIB 6021\ud 43PR), from the Spanish Ministry of Science and Innovation\ud (CSIC (200930I009) and from Instituto Español de Oceano -\ud grafía (project CCIEO).Peer reviewe