The Phycobilin Signatures of Chloroplasts from Three Dinoflagellate Species: A Microanalytical Study of Dinophysis Caudata, D. Fortii, and D. Acuminata (Dinophysiales, Dinophyceae) (original) (raw)
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Most 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- ...
Harmful Algae, 2010
Most species belonging to the toxigenic genus Dinophysis have chloroplasts of cryptophyte origin. Whether these chloroplasts are temporarily sequestered from the prey, or permanently established under the control of the dinoflagellate is currently disputed. To investigate this, a culture of Dinophysis acuminata was established by feeding it the phototrophic ciliate Mesodinium rubrum (= Myrionecta rubra), which again was fed the cryptophyte Teleaulax amphioxeia. Molecular analysis comprising the nucleomorph LSU and two chloroplast markers (tufA gene and a fragment from the end of 16S rDNA to the beginning of 23S rDNA) resulted in identical sequences for the three organisms. Yet, transmission electron microscopy of the three organisms revealed that several chloroplast features separated D. acuminata from both T. amphioxeia and M. rubrum. The thylakoid arrangement, the number of membranes around the chloroplast as well as the position and the arrangement of the pyrenoids were strikingly different. Considering both molecular and ultrastructural evidence, our data indicated that the chloroplasts in D. acuminata are permanent chloroplasts originating within Teleaulax or another closely related cryptophyte genus. Electron microscopy also provided new information on the peduncle of D. acuminata, which is used in food uptake. ß
Journal of Plankton Research, 2012
Despite the discussion around the nature of plastids in Dinophysis, a comparison of pigment signatures in the three-culture system (Dinophysis, the ciliate Mesodinium rubrum and the cryptophyte Teleaulax amphioxeia) has never been reported. We observed similar pigment composition, but quantitative differences, in four Dinophysis species (D. acuminata, D. acuta, D. caudata and D. tripos), Mesodinium and Teleaulax. Dinophysis contained 59-221-fold higher Chl a per cell than T. amphioxeia (depending on the light conditions and species). To explain this result, several reasons (e.g. more chloroplasts than previously appreciated and synthesis of new pigments) are suggested.
Photoregulation in a Kleptochloroplastidic Dinoflagellate, Dinophysis acuta
Frontiers in microbiology, 2016
Some phagotrophic organisms can retain chloroplasts of their photosynthetic prey as so-called kleptochloroplasts and maintain their function for shorter or longer periods of time. Here we show for the first time that the dinoflagellate Dinophysis acuta takes control over "third-hand" chloroplasts obtained from its ciliate prey Mesodinium spp. that originally ingested the cryptophyte chloroplasts. With its kleptochloroplasts, D. acuta can synthesize photosynthetic as well as photoprotective pigments under long-term starvation in the light. Variable chlorophyll fluorescence measurements showed that the kleptochloroplasts were fully functional during 1 month of prey starvation, while the chlorophyll a-specific inorganic carbon uptake decreased within days of prey starvation under an irradiance of 100 μmol photons m(-2) s(-1). While D. acuta cells can regulate their pigmentation and function of kleptochloroplasts they apparently lose the ability to maintain high inorganic carb...
Light and electron microscopical observations on Protoceratium reficulatum (Dinophyceae)
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Proceedings of the Royal Society of London, 1990
Affinity-purified antibodies prepared against the peridinin-chlorophyll aprotein (POP) complex from the dinoflagellate pygmaea were employed to study the immunological similarity of PCP among 28 dinoflagellate species, representing eight genera in four families. The anti-HpPCP antibodies cross-reacted with the subunits of PCP apoproteins from all dinoflagellates tested, but did not cross-react with pigment proteins from the chrysophyte Cricosphaera establishing its specificity for dinoflagellate pigment-protein complexes. Among the dinoflagellates, the PCP apoprotein occurs either as a monomer of about 35 kDa or as an apparent homodimer of about 15 kDa. In some instances, both subunit polypeptides are present simultaneously. The occurrence of different quaternary structures of the PCP apoprotein in different algae can serve as a taxonomic tool, when used in conjunction with other characters. Abbreviations used in the text: PCP, peridinin-chlorophyll a-protein; anti-HpPCP, antibodies against PCP from Heterocapsa ; SDS-page, sodium dodecyl sulphate polyacrylamide gel electrophoresis.
Multiple Plastids Collected by the Dinoflagellate Dinophysis mitra through Kleptoplastidy
Applied and Environmental Microbiology, 2011
Kleptoplastidy is the retention of plastids obtained from ingested algal prey, which may remain temporarily functional and be used for photosynthesis by the predator. We showed that the marine dinoflagellate Dinophysis mitra has great kleptoplastid diversity. We obtained 308 plastid rbc L sequences by gene cloning from 14 D. mitra cells and 102 operational taxonomic units (OTUs). Most sequences were new in the genetic database and positioned within Haptophyceae (227 sequences [73.7%], 80 OTUs [78.4%]), particularly within the genus Chrysochromulina . Others were closely related to Prasinophyceae (16 sequences [5.2%], 5 OTUs [4.9%]), Dictyochophyceae (14 sequences [4.5%], 5 OTUs [4.9%]), Pelagophyceae (14 sequences [4.5%], 1 OTU [1.0%]), Bolidophyceae (3 sequences [1.0%], 1 OTU [1.0%]), and Bacillariophyceae (1 sequence [0.3%], 1 OTU [1.0%]); however, 33 sequences (10.8%) as 9 OTUs (8.8%) were not closely clustered with any particular group. Only six sequences were identical to those...
PLOS ONE
Species within the marine toxic dinoflagellate genus Dinophysis are phagotrophic organisms that exploit chloroplasts (kleptochloroplasts) from other protists to perform photosynthesis. Dinophysis spp. acquire the kleptochloroplasts from the ciliate Mesodinium rubrum, which in turn acquires the chloroplasts from a unique clade of cryptophytes. Dinophysis spp. digest the prey nuclei and all other cell organelles upon ingestion (except the kleptochloroplasts) and they are therefore believed to constantly acquire new chloroplasts as the populations grow. Previous studies have, however, indicated that Dinophysis can keep the kleptochloroplasts active during long term starvation and are able to produce photosynthetic pigments when exposed to prey starvation. This indicates a considerable control over the kleptochloroplasts and the ability of Dinophysis to replicate its kleptochloroplasts was therefore re-investigated in detail in this study. The kleptochloroplasts of Dinophysis acuta and Dinophysis acuminata were analyzed using confocal microscopy and 3D bioimaging software during long term starvation experiments. The cell concentrations were monitored to confirm cell divisions and samples were withdrawn each time a doubling had occurred. The results show direct evidence of kleptochloroplastidic division and that the decreases in total kleptochloroplast volume, number of kleptochloroplasts and number of kleptochloroplast centers were not caused by dilution due to cell divisions. This is the first report of division of kleptochloroplasts in any protist without the associated prey nuclei. This indicates that Dinophysis spp. may be in a transitional phase towards possessing permanent chloroplasts, which thereby potentially makes it a key organism to understand the evolution of phototrophic protists.
Journal of Phycology, 1999
The Crypthecodinium cohnii-like heterotrophic dinoflagellate preys on the cells of the red microalga Porphyridium sp. UTEX 637, and not on other microalgae. The dinoflagellate contains enzymes that degrade the cell wall complex of this species of alga and not that of other red microalgae. The cells of the red microalgae are encapsulated within a cell wall complex composed of about 10 sugars, sulfate, and proteins. We previously hypothesized that the dinoflagellate recognizes the cell wall of this alga. In this study, we have shown that the biorecognition site is the 66-kDa glycoprotein in the algal cell wall complex. The methodology used in this study was based on changing the algal cell wall composition and examining the prey and chemosensory response of the dinoflagellate. The dinoflagellate was not attracted to the cell wall of other red microalgae, which are similar to that of Porphyridium sp., or to sugars composing its cell wall. However, the dinoflagellate preyed on and was attracted to Porphyridium sp. mutants (DCB resistant) having modified cell wall polysaccharide composition, probably because the 66-kDa cell wall glycoprotein was not changed. The dinoflagellate did not respond chemotactically to enzymatically degraded cell wall complex. Treatment of the cell wall complex with antiserum to the 66-kDa glycoprotein or with the lectin concanavalin A (con A), which binds specifically to ␣-D-mannosyl and ␣-D-glucosyl residues, did not affect the chemotactic attraction. However, prey by the dinoflagellate was prevented when the algal cells were blocked with antiserum specific to the 66-kDa glycoprotein or with con A. These latter results provide direct proof that the 66-kDa cell wall glycoprotein is 1 the recognition site and prey-prevention results from the blocking of this site on the cell wall.