Light, electron microscopy and DNA sequences of the dinoflagellate Prorocentrum concavum (syn. P. Arabianum) with special emphasis on the periflagellar area (original) (raw)
Related papers
2007
This study was carried out to investigate the morphological relationship between Prorocentrum and Dinophysis, and to identify other characteristics (morphology and new gene-cytochrome b) to improve the classification of Prorocentrum. To achieve these objectives ultrastructural study (SEM and TEM) were carried out on D. acuminata and P. hoffmaniannum. Results showed that Dinophysis has 4 platelets surrounding the flagellar pore as has been suggested in study elsewhere. Prorocentrum hoffmaniannum has 8 platelets in the periflagellar area and SEM is not suitable to determine the number of platelets for Prorocentrum species. The relationship between these two genera based on platelets configuration cannot be resolved until more Dinophysis species have been studied. Prior to molecular analysis, the morphology characteristics of six Prorocentrum species were identified using light and SEM. The morphological characteristic of these Prorocentrum species agreed well with previous description...
The Journal of eukaryotic microbiology, 2017
Prorocentrum mexicanum and P. rhathymum are toxicologically important dinoflagellates, but their relationship is not well defined. We investigated strains from Puerto Rico and Brazil by light and scanning electron microscopies. We provide molecular data from a strain isolated near the type locality of P. rhathymum, and the first morphological and molecular data from the South Atlantic Ocean. The rRNA gene (rDNA) sequences of the Puerto Rican and Brazilian strains were identical, and their morphologies fit the description of P. rhathymum. In the molecular phylogenies, the globally distributed populations under the names P. mexicanum and P. rhathymum are intermixed and branched together, except for several divergent strains from Florida and Cuba. We examined the original descriptions and iconotypes of the species P. maximum, P. brochii, P. mexicanum and P. rhathymum. We conclude that P. maximum sensu Schiller's figure 41a corresponds to the earlier description of this species; the...
Journal of Phycology, 2011
Wild and cultured specimens of Prorocentrum lima (Ehrenb.) F. Stein from 26 widely different areas in 13 countries were examined in order to determine consistent characters for delimiting species boundaries in this taxon. The morphological characters valve shape, valve size, valve ornamentation, number and shape of valve pores, number and shape of marginal pores, and periflagellar platelets were observed using LM and SEM, and two molecular genetic regions were sequenced. We identified stable morphological characters that were consistent among wild specimens and all cultures, which were valve shape, valve ornamentation, and number and arrangement of periflagellar platelets. All cultures of P. lima identified by these characters formed a monophyletic group in phylogenetic analyses based on the two genes, which, however, included the species Prorocentrum arenarium. P. arenarium was determined to be within the range of morphological variation of P. lima, and therefore we synonymize the ...
A New Clade, Based on Partial LSU rDNA Sequences, of Unarmoured Dinoflagellates
Protist, 2013
The user has requested enhancement of the downloaded file. All in-text references underlined in blue are added to the original document and are linked to publications on ResearchGate, letting you access and read them immediately. This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.
Despite their evolutionary and ecological importance, dinoflagellate phylogeny remains poorly resolved. Here we explored the utility of mitochondrial cytochrome b (cob) in inferring a dinoflagellate tree and focused on resolving the relationship between fucoxanthin-and peridinin-containing taxa. Trees were inferred using cob and small subunit rDNA alone or in combination as concatenated data and including members of the six major dinoflagellate orders. Many regions of the cob DNA or protein and rDNA trees were congruent with support for the monophyly of Symbiodinium spp. Freudenthal and of the Prorocentrales and the early divergence of Crypthecodinium cohnii Seligo in Grasse. However, these markers provided differing support for the monophyly of Pfiesteria spp. Steidinger et Burkholder (only supported strongly by rDNA) and of the fucoxanthin dinoflagellates with Akashiwo sp. (Hirasaka) Hansen et Moestrup (Gymnodiniales, only supported strongly by the cob data). The approximately unbiased (AU) test was used to assess these results using 13-and 11-taxon (excluding apicomplexans) backbone maximum likelihood trees inferred from the combined cob þ rDNA data. The AU test suggested that our data were insufficient to resolve the phylogenetic position of Symbiodinium spp. and that the ancestral position of C. cohnii might have resulted from long-branch attraction to the apicomplexan outgroup. We found significant support, however, for the association of fucoxanthin dinoflagellates with Akashiwo sp. The monophyly and relatively derived position of the Gymnodiniales in our cob DNA and protein trees and in the cob þ rDNA tree is consistent with the tertiary endosymbiotic origin of the plastid in fucoxanthin dinoflagellates.
Journal of Phycology, 2005
Despite their evolutionary and ecological importance, dinoflagellate phylogeny remains poorly resolved. Here we explored the utility of mitochondrial cytochrome b (cob) in inferring a dinoflagellate tree and focused on resolving the relationship between fucoxanthin-and peridinin-containing taxa. Trees were inferred using cob and small subunit rDNA alone or in combination as concatenated data and including members of the six major dinoflagellate orders. Many regions of the cob DNA or protein and rDNA trees were congruent with support for the monophyly of Symbiodinium spp. Freudenthal and of the Prorocentrales and the early divergence of Crypthecodinium cohnii Seligo in Grasse. However, these markers provided differing support for the monophyly of Pfiesteria spp. Steidinger et Burkholder (only supported strongly by rDNA) and of the fucoxanthin dinoflagellates with Akashiwo sp. (Hirasaka) Hansen et Moestrup (Gymnodiniales, only supported strongly by the cob data). The approximately unbiased (AU) test was used to assess these results using 13-and 11-taxon (excluding apicomplexans) backbone maximum likelihood trees inferred from the combined cob+rDNA data. The AU test suggested that our data were insufficient to resolve the phylogenetic position of Symbiodinium spp. and that the ancestral position of C. cohnii might have resulted from long-branch attraction to the apicomplexan outgroup. We found significant support, however, for the association of fucoxanthin dinoflagellates with Akashiwo sp. The monophyly and relatively derived position of the Gymnodiniales in our cob DNA and protein trees and in the cob+rDNA tree is consistent with the tertiary endosymbiotic origin of the plastid in fucoxanthin dinoflagellates.
The toxic dinoflagellate Prorocentrum lima and its associated bacteria
European Journal of Protistology, 1995
An immunofluorescence method, using a monoclonal ant ibody aga inst ok adaic acid (OA) to xin and DNA sta ining, wa s used to visualize the tox in and extranuclear DNA wh ich could possibly be of int racellular bacterial orig in, in the dinoflagellate species Pr orocentrum lima Ehrenberg (Dodge). Ok ad aic acid (OA) was detected within the cytopl asm of the din oflagellate cell, frequentl y near the cytoplasmic membrane in the cell periphery and occasionall y close to the nuclear memb rane in the center of the cytopl asm. Th ese result s suggest that OA production could be related to the peripheral chloro plast and th at OA accumulation may be associated with membrane lipids. OA is not co-localized with extranuclear DNA, imply ing that intracellular bacteria do not contain or accumulate the toxin. Comparison between axenic and no n-axenic dinoflagellate cultures showed no differen ces in immunolabelling, suggesting that ext racellular associated bacteria are not essenti al to ok ad aic acid production by the P. lima culture. Th ese results tend to show that the dinoflagellat e cell is able to produce OA autonomously.
Journal of Molecular Evolution, 2007
Many outstanding questions about dinoflagellate evolution can potentially be resolved by establishing a robust phylogeny. To do this, we generated a data set of mitochondrial cytochrome b (cob) and mitochondrial cytochrome c oxidase 1 (cox1) from a broad range of dinoflagellates. Maximum likelihood, maximum parsimony, and Bayesian methods were used to infer phylogenies from these genes separately and as a concatenated alignment with and without small subunit (SSU) rDNA sequences. These trees were largely congruent in topology with previously published phylogenies but revealed several unexpected results. Prorocentrum benthic and planktonic species previously placed in different clusters formed a monophyletic group in all trees, suggesting that the Prorocentrales is a monophyletic group. More strikingly, our analyses placed Amphidinium and Heterocapsa as early splits among dinoflagellates that diverged after the emergence of O. marina. This affiliation received strong bootstrap support, but these lineages exhibited relatively long branches. The approximately unbiased (AU-) test was used to assess this result using a three-gene (cob + cox1 + SSU rDNA) DNA data set and the inferred tree. This analysis showed that forcing Amphidinium or Heterocapsa to relatively more derived positions in the phylogeny resulted in significantly lower likelihood scores, consistent with the phylogenies. The position of these lineages needs to be further verified.
Plankton and Benthos Research, 2011
The taxonomic position of an armored dinoflagellate Prorocentrum donghaiense Lu, 2001, which is one of the causative species of large red tides occurring off Changjiang River mouth was examined and compared to a similar species P. shikokuense. In both species, the following morphological features were shared; a weakly concave cell with a tiny apical spine around the periflagellar area, one side of the cell being slightly extended on the anterior end, a rounded posterior end, a rounded nucleus located in the posterior region and similar size of cells. DNA sequences of small subunit rDNA and internal transcribed spacer 1 (ITS1)-5.8S rDNA-ITS2 regions of these two species were largely the same. Morphological and molecular data suggest that P. donghaiense and P. shikokuense are synonymous and P. shikokuense has priority over P. donghaiense.