Phylogeny and Morphology of New Diplonemids from Japan

Tashyreva, Daria; Prokopchuk, Galina; Yabuki, Akinori; Kaur, Binnypreet; Faktorová, Drahomíra; Votýpka, Jan; Kusaka, Chiho; Fujikura, Katsunori; Shiratori, Takashi; Ishida, Koichi; Horák, Aleš; Lukeš, Julius

doi:10.1016/j.protis.2018.02.001

Cited by 45 publications

(49 citation statements)

References 60 publications

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“…; Tashyreva et al. ), although there is no direct data in support of this for the eupelagonemids specifically. Since diplonemids, and especially eupelagonemids, are so poorly known and what we do know suggests they are probably very diverse, it is premature to propose a simple morphological synapomorphy for the whole group.…”

Section: Resultsmentioning

confidence: 99%

“…The newly described genera are also marine, though their habitats are yet to be clarified (Tashyreva et al. ). Some of these diplonemids have been studied mostly due to their relationship to the more famous kinetoplastids, and because of their baroque mitochondrial genome architecture and posttranscriptional editing characteristics (Kiethega et al.…”

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confidence: 99%

“…But overall, the group has not been extensively described, with multiple undetermined phylotypes present in environmental molecular surveys (Tashyreva et al. ,b).…”

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confidence: 99%

“…A fourth proposed genus, Isonema, is generally considered a junior synonym of Diplonema (Triemer and Ott 1990). In 2018, three new diplonemid genera were reported (Lacrimia, Sulcionema, and Flectonema) (Tashyreva et al 2018a), and novel morphological and behavioral features, as well as endosymbionts, were described for the genus Diplonema (Tashyreva et al 2018b), demonstrating the under-explored diversity of this group.…”

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confidence: 99%

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A Revised Taxonomy of Diplonemids Including the Eupelagonemidae n. fam. and a Type Species, Eupelagonema oceanica n. gen. & sp.

Okamoto

Gawryluk

Campo

et al. 2018

J Eukaryotic Microbiology

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Recent surveys of marine microbial diversity have identified a previously unrecognized lineage of diplonemid protists as being among the most diverse heterotrophic eukaryotes in global oceans. Despite their monophyly (and assumed importance), they lack a formal taxonomic description, and are informally known as deep-sea pelagic diplonemids (DSPDs) or marine diplonemids. Recently, we documented morphology and molecular sequences from several DSPDs, one of which is particularly widespread and abundant in environmental sequence data. To simplify the communication of future work on this important group, here we formally propose to erect the family Eupelagonemidae to encompass this clade, as well as a formal genus and species description for the apparently most abundant phylotype, Eupelagonema oceanica, for which morphological information and single-cell amplified genome data are currently available.

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Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

“…But overall, the group has not been extensively described, with multiple undetermined phylotypes present in environmental molecular surveys (Tashyreva et al. ,b).…”

mentioning

confidence: 99%

mentioning

confidence: 99%

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A Revised Taxonomy of Diplonemids Including the Eupelagonemidae n. fam. and a Type Species, Eupelagonema oceanica n. gen. & sp.

Okamoto

Gawryluk

Campo

et al. 2018

J Eukaryotic Microbiology

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“…The large fraction of repetitive DNA (65%) and relatively high proportion of foldback DNA (14%) may be responsible for the continually condensed structure of the Euglena chromosomes (Rawson et al, 1979). Permanently condensed heterochromatin was recently observed also in diplonemids (Tashyreva et al, 2018). In trypanosomes, the chromosomes are not condensed at any stage of the mitotic cycle (Gull et al, 1998;Minning et al, 2011;Souza et al, 2011).…”

Section: (6) a Comparison Of The Nucleus And Mitosis In Trypanosomatimentioning

confidence: 99%

Comparative molecular cell biology of phototrophic euglenids and parasitic trypanosomatids sheds light on the ancestor of Euglenozoa

et al. 2019

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Parasitic trypanosomatids and phototrophic euglenids are among the most extensively studied euglenozoans. The phototrophic euglenid lineage arose relatively recently through secondary endosymbiosis between a phagotrophic euglenid and a prasinophyte green alga that evolved into the euglenid secondary chloroplast. The parasitic trypanosomatids (i.e. Trypanosoma spp. and Leishmania spp.) and the freshwater phototrophic euglenids (i.e. Euglena gracilis) are the most evolutionary distant lineages in the Euglenozoa phylogenetic tree. The molecular and cell biological traits they share can thus be considered as ancestral traits originating in the common euglenozoan ancestor. These euglenozoan ancestral traits include common mitochondrial presequence motifs, respiratory chain complexes containing various unique subunits, a unique ATP synthase structure, the absence of mitochondria‐encoded transfer RNAs (tRNAs), a nucleus with a centrally positioned nucleolus, closed mitosis without dissolution of the nuclear membrane and nucleoli, a nuclear genome containing the unusual ‘J’ base (β‐D‐glucosyl‐hydroxymethyluracil), processing of nucleus‐encoded precursor messenger RNAs (pre‐mRNAs) via spliced‐leader RNA (SL‐RNA) trans‐splicing, post‐transcriptional gene silencing by the RNA interference (RNAi) pathway and the absence of transcriptional regulation of nuclear gene expression. Mitochondrial uridine insertion/deletion RNA editing directed by guide RNAs (gRNAs) evolved in the ancestor of the kinetoplastid lineage. The evolutionary origin of other molecular features known to be present only in either kinetoplastids (i.e. polycistronic transcripts, compaction of nuclear genomes) or euglenids (i.e. monocistronic transcripts, huge genomes, many nuclear cis‐spliced introns, polyproteins) is unclear.

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Massive mitochondrial DNA content in diplonemid and kinetoplastid protists

et al. 2018

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SummaryThe mitochondrial DNA of diplonemid and kinetoplastid protists is known for its suite of bizarre features, including the presence of concatenated circular molecules, extensive trans‐splicing and various forms of RNA editing. Here we report on the existence of another remarkable characteristic: hyper‐inflated DNA content. We estimated the total amount of mitochondrial DNA in four kinetoplastid species (Trypanosoma brucei, Trypanoplasma borreli, Cryptobia helicis, and Perkinsela sp.) and the diplonemid Diplonema papillatum. Staining with 4′,6‐diamidino‐2‐phenylindole and RedDot1 followed by color deconvolution and quantification revealed massive inflation in the total amount of DNA in their organelles. This was further confirmed by electron microscopy. The most extreme case is the ∼260 Mbp of DNA in the mitochondrion of Diplonema, which greatly exceeds that in its nucleus; this is, to our knowledge, the largest amount of DNA described in any organelle. Perkinsela sp. has a total mitochondrial DNA content ~6.6× greater than its nuclear genome. This mass of DNA occupies most of the volume of the Perkinsela cell, despite the fact that it contains only six protein‐coding genes. Why so much DNA? We propose that these bloated mitochondrial DNAs accumulated by a ratchet‐like process. Despite their excessive nature, the synthesis and maintenance of these mtDNAs must incur a relatively low cost, considering that diplonemids are one of the most ubiquitous and speciose protist groups in the ocean. © 2018 The Authors. IUBMB Life published by Wiley Periodicals, Inc. on behalf of International Union of Biochemistry and Molecular Biology., 70(12):1267–1274, 2018

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Phylogeny and Morphology of New Diplonemids from Japan

Cited by 45 publications

References 60 publications

A Revised Taxonomy of Diplonemids Including the Eupelagonemidae n. fam. and a Type Species, Eupelagonema oceanica n. gen. & sp.

A Revised Taxonomy of Diplonemids Including the Eupelagonemidae n. fam. and a Type Species, Eupelagonema oceanica n. gen. & sp.

Comparative molecular cell biology of phototrophic euglenids and parasitic trypanosomatids sheds light on the ancestor of Euglenozoa

Massive mitochondrial DNA content in diplonemid and kinetoplastid protists

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