Species of the Parasitic Genus Duboscquella are Members of the Enigmatic Marine Alveolate Group I

Harada, A.; Ohtsuka, Susumu; Horiguchi, Takeo

doi:10.1016/j.protis.2007.03.005

Cited by 87 publications

(84 citation statements)

References 29 publications

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“…In contrast, P. chabelardi, which has been previously determined as Perkinsus-like (Gestal et al, 2006), is placed with high statistical support within group 1 of the MAs in our work (Figure 1), suggesting that previous classifications were incorrect (Gestal et al, 2006). The placing of P. chabelardi in MA group 1, strengthens the view that this alveolate group is entirely parasitic (see Groisillier et al, 2006;Harada et al, 2006;Dolven et al, 2007;Guillou et al, 2008).…”

Section: Phylogeny Of Enigmatic Perkinsoid Speciessupporting

confidence: 74%

Freshwater Perkinsea and marine-freshwater colonizations revealed by pyrosequencing and phylogeny of environmental rDNA

et al. 2010

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Protist parasites are ecologically important, as they can have great impact on host population dynamics and functioning of entire ecosystems. Nevertheless, little is known about their prevalence in aquatic habitats. Here, we investigate the diversity and distributional patterns of the protist parasites Perkinsus and Parvilucifera (Perkinsea). Our approach included 454 pyrosequencing of the 18S rDNA gene obtained from a high-altitude lake (Lake Finsevatn, Norway) and phylogenetic analyses of all publicly available sequences related to Perkinsea. The applied PCR primers target a 450 bp region that encompass the variable V4 region of the 18S rDNA gene and have been optimized for the Titanium upgrade of the 454 technology. Nearly 5000 sequences longer than 150 bp were recovered from nearly all eukaryotic supergroups, and of those, 13 unique sequences were affiliated to Perkinsea. Thus, our new strategy for 454 amplicon sequencing was able to recover a large diversity of distantly related eukaryotes and previously unknown species of Perkinsea. In addition, we identified 40 Perkinsea sequences in GenBank generated by other recent diversity surveys. Importantly, phylogenetic analyses of these sequences identified 17 habitat-specific marine and freshwater clades . Hence, only a few successful transitions between these habitats have taken place over the entire history of Perkinsea, suggesting that the boundary between marine and fresh waters may constitute a barrier to cross-colonizations for intracellular parasites.

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Section: Phylogeny Of Enigmatic Perkinsoid Speciessupporting

confidence: 74%

Freshwater Perkinsea and marine-freshwater colonizations revealed by pyrosequencing and phylogeny of environmental rDNA

et al. 2010

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“…The consistency of the two clone libraries suggests that multiple copies of 18S rRNA genes in Duboscquella likely contributed to the cluster formation. Thus, previous findings of large fractions of clones and pyrotags being related to Duboscquella and other parasitic dinophytes (Harada et al, 2007;Brown et al, 2009) these groups to the composition of marine protist communities. Alternatively, differences in Duboscquella frequency in clone versus SAG libraries may have been caused by multiple parasitic cells residing inside individual, sorted protists.…”

Section: Discussionmentioning

confidence: 64%

“…Heterotrophic protists also have an important role in the microbial loop and the marine carbon cycle through respiration, grazing on phytoplankton and heterotrophic microbes and by being a food source to zooplankton (Azam et al, 1983;Fuhrman and McManus, 1984;Yokokawa and Nagata, 2005;Jeong et al, 2008). Many marine protists function as mixotrophs (Zubkov and Tarran, 2008;de Castro et al, 2009), harbor endosymbionts (Buck and Bentham, 1998;Not et al, 2007b) or parasitize other eukaryotes (Harada et al, 2007;Brown et al, 2009), demonstrating their diverse and complex ecological roles.…”

Section: Introductionmentioning

confidence: 99%

Capturing diversity of marine heterotrophic protists: one cell at a time

et al. 2010

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Recent applications of culture-independent, molecular methods have revealed unexpectedly high diversity in a variety of functional and phylogenetic groups of microorganisms in the ocean. However, none of the existing research tools are free from significant limitations, such as PCR and cloning biases, low phylogenetic resolution and others. Here, we employed novel, single-cell sequencing techniques to assess the composition of small (o10 lm diameter), heterotrophic protists from the Gulf of Maine. Single cells were isolated by flow cytometry, their genomes amplified, and 18S rRNA marker genes were amplified and sequenced. We compared the results to traditional environmental PCR cloning of sorted cells. The diversity of heterotrophic protists was significantly higher in the library of single amplified genomes (SAGs) than in environmental PCR clone libraries of the 18S rRNA gene, obtained from the same coastal sample. Libraries of SAGs, but not clones contained several recently discovered, uncultured groups, including picobiliphytes and novel marine stramenopiles. Clone, but not SAG, libraries contained several large clusters of identical and nearly identical sequences of Dinophyceae, Cercozoa and Stramenopiles. Similar results were obtained using two alternative primer sets, suggesting that PCR biases may not be the only explanation for the observed patterns. Instead, differences in the number of 18S rRNA gene copies among the various protist taxa probably had a significant role in determining the PCR clone composition. These results show that single-cell sequencing has the potential to more accurately assess protistan community composition than previously established methods. In addition, the creation of SAG libraries opens opportunities for the analysis of multiple genes or entire genomes of the uncultured protist groups.

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“…The Novel Alveolate groups I and II (Groisillier et al, 2006) collectively contributed to 12.4, 23.6 and 21.2% of tag sequence abundance at 10, 800 and 4400 m, respectively. Recently, sequences clustering within these clades have been identified as representing endoparasitic dinoflagellates related to the genera Amoebophyra (Kim et al, 2008) and Duboscquella (Harada et al, 2007). Infection by both genera is mediated by the production of dispersal spores and infections and is mostly lethal (Kim et al, 2008).…”

Section: Discussionmentioning

confidence: 99%

Microbial community structure in the North Pacific ocean

et al. 2009

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We report a ribosomal tag pyrosequencing study of the phylogenetic diversity of Archaea, Bacteria and Eucarya over a depth profile at the Hawaii Ocean Time-Series Station, ALOHA. The V9 region of the SSU rRNA gene was amplified from samples representing the epi-(10 m), meso-(800 m) and bathy-(4400 m) pelagia. The primers used are expected to amplify representatives of B80% of known phylogenetic diversity across all three domains. Comparisons of unique sequences revealed a remarkably low degree of overlap between communities at each depth. The 444 147 sequence tags analyzed represented 62 975 unique sequences. Of these, 3707 (5.9%) occurred at two depths, and only 298 (0.5%) were observed at all three depths. At this level of phylogenetic resolution, Bacteria diversity decreased with depth but was still equivalent to that reported elsewhere for different soil types. Archaea diversity was highest in the two deeper samples. Eucarya observations and richness estimates are almost one order of magnitude higher than any previous marine microbial Eucarya richness estimates. The associations of many Eucarya sequences with putative parasitic organisms may have significant impacts on our understanding of the mechanisms controlling host population density and diversity, and point to a more significant role for microbial Eucarya in carbon flux through the microbial loop. We posit that the majority of sequences detected from the deep sea that have closest matches to sequences from non-pelagic sources are indeed native to the marine environment, and are possibly responsible for key metabolic processes in global biogeochemical cycles.

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Species of the Parasitic Genus Duboscquella are Members of the Enigmatic Marine Alveolate Group I

Cited by 87 publications

References 29 publications

Freshwater Perkinsea and marine-freshwater colonizations revealed by pyrosequencing and phylogeny of environmental rDNA

Freshwater Perkinsea and marine-freshwater colonizations revealed by pyrosequencing and phylogeny of environmental rDNA

Capturing diversity of marine heterotrophic protists: one cell at a time

Microbial community structure in the North Pacific ocean

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