The hemimastigophora (Hemimastix amphikineta nov. gen., nov. spec.), a new protistan phylum from gondwanian soils

Foissner, Wilhelm; Blatterer, Hubert; Foissner, Ilse

doi:10.1016/s0932-4739(88)80027-0

Cited by 43 publications

(19 citation statements)

References 45 publications

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“…When sulfur is available, they generate hydrogen sulfide (16). Although severely hindered by ambient oxygen, they are (28). Hemimastigophorans probably evolved from members of the kinetoplastid-euglenid taxon (29).…”

Section: The ''Thiodendron'' Stagementioning

confidence: 99%

The chimeric eukaryote: Origin of the nucleus from the karyomastigont in amitochondriate protists

Margulis

Dolan

Guerrero

2000

Proc. Natl. Acad. Sci. U.S.A.

176

107

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We present a testable model for the origin of the nucleus, the membrane-bounded organelle that defines eukaryotes. A chimeric cell evolved via symbiogenesis by syntrophic merger between an archaebacterium and a eubacterium. The archaebacterium, a thermoacidophil resembling extant Thermoplasma, generated hydrogen sulfide to protect the eubacterium, a heterotrophic swimmer comparable to Spirochaeta or Hollandina that oxidized sulfide to sulfur. Selection pressure for speed swimming and oxygen avoidance led to an ancient analogue of the extant cosmopolitan bacterial consortium ''Thiodendron latens.'' By eubacterial-archaebacterial genetic integration, the chimera, an amitochondriate heterotroph, evolved. This ''earliest branching protist'' that formed by permanent DNA recombination generated the nucleus as a component of the karyomastigont, an intracellular complex that assured genetic continuity of the former symbionts. The karyomastigont organellar system, common in extant amitochondriate protists as well as in presumed mitochondriate ancestors, minimally consists of a single nucleus, a single kinetosome and their protein connector. As predecessor of standard mitosis, the karyomastigont preceded free (unattached) nuclei. The nucleus evolved in karyomastigont ancestors by detachment at least five times (archamoebae, calonymphids, chlorophyte green algae, ciliates, foraminifera). This specific model of syntrophic chimeric fusion can be proved by sequence comparison of functional domains of motility proteins isolated from candidate taxa.Archaeprotists ͉ spirochetes ͉ sulfur syntrophy ͉ Thiodendron ͉ trichomonad Two Domains, Not Three

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Section: The ''Thiodendron'' Stagementioning

confidence: 99%

The chimeric eukaryote: Origin of the nucleus from the karyomastigont in amitochondriate protists

Margulis

Dolan

Guerrero

2000

Proc. Natl. Acad. Sci. U.S.A.

176

107

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“…A transitional helix (TH) occurs in the Chrysophyta, Eustigmatophyta, and Xanthophyta. A TH-like structure is found in one genus of the Prasinophyta (Pyrarnirnonas; Moestrup and Thomsen 1974), in the euglenoid Entosiphon (Mignot 1966), and in a number of protists with uncertain taxonomic affinities (Phalansteriurn (Hibberd 1983); Hernirnastix (Foissner et al 1988)). …”

Section: Taxonomy and Ultrastructurementioning

confidence: 99%

“…The Bicosoecidae are apparently unique among the zooflagellates in possessing basal bodies that match those of Cryothecornonas in length (700 nm; Moestrup and Thomsen 1976). Typical values for genera incertae sedis are as follows: Hernirnastix, 180-250 nm (Foissner et al 1988); Apusornonas, 350 nm (Karpoff and Zhukov 1986); Cercornonas, 450 nm (Mylnikov 1986); and Discocelis, 300 nm (Vgrs 1988).…”

Section: Taxonomy and Ultrastructurementioning

confidence: 99%

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Fine structure and biology of Cryothecomonas gen. nov. (Protista incertae sedis) from the ice biota

Thomsen¹,

Buck²,

Bolt³

et al. 1991

Can. J. Zool.

103

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1991. Fine structure and biology of Cryothecomonas gen.nov. (Protista incertae sedis) from the ice biota. Can. J. Zool. 69: 1048-1070. The morphology and ultrastructure of four species of Cryothecomonas gen.nov. (Protista incertae sedis) in material from the Weddell Sea, Antarctica, and the Isefjord, Denmark, are described. These heterotrophic flagellates, which were initially observed in association with sea ice, display a unique combination of morphological characteristics. At present it is impossible to assign the new genus to an existing higher taxonomic level of protistan flagellates. Cryothecomonas species are furnished with a close-fitting multilayered theca. The two naked anterior flagella emerge through narrow thecal funnels. A transitional helix is part of the flagellar transition zone. A conspicuous cytostome is located in a posterior (lateral) position. Food uptake is mediated through the extension of cytostomal pseudopodia. The nucleus is anteriorly located and contains a conspicuous nucleolus and distinct areas of chromatin. Mitochondria1 cristae are tubular. Cryothecomonas species feed on cells in the size range 2-4.5 k m (e.g., algal flagellates). Data are presented on the abundance of Cryothecomonas armigera sp.nov. in Antarctic waters.

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“…EUKARYOTES INCERTAE SEDIS (Foissner et al 1988;Brugerolle et al 2002;Kim et al 2006) Some eukaryotic taxa remain unplaced: through being inadequately described, genuinely difficult to place or genuinely not closely related to any other group. The taxa listed here are a small proportion of incertae sedis eukaryotes, selected on the basis of recent publication and current phylogenetic interest.…”

Section: Endomyxamentioning

confidence: 99%

Eukaryotic systematics: a user's guide for cell biologists and parasitologists

et al. 2011

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Single-celled parasites like Entamoeba, Trypanosoma, Phytophthora and Plasmodium wreak untold havoc on human habitat and health. Understanding the position of the various protistan pathogens in the larger context of eukaryotic diversity informs our study of how these parasites operate on a cellular level, as well as how they have evolved. Here, we review the literature that has brought our understanding of eukaryotic relationships from an idea of parasites as primitive cells to a crystallized view of diversity that encompasses 6 major divisions, or supergroups, of eukaryotes. We provide an updated taxonomic scheme (for 2011), based on extensive genomic, ultrastructural and phylogenetic evidence, with three differing levels of taxonomic detail for ease of referencing and accessibility (see supplementary material at Cambridge Journals On-line). Two of the most pressing issues in cellular evolution, the root of the eukaryotic tree and the evolution of photosynthesis in complex algae, are also discussed along with ideas about what the new generation of genome sequencing technologies may contribute to the field of eukaryotic systematics. We hope that, armed with this user's guide, cell biologists and parasitologists will be encouraged about taking an increasingly evolutionary point of view in the battle against parasites representing real dangers to our livelihoods and lives.

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The hemimastigophora (Hemimastix amphikineta nov. gen., nov. spec.), a new protistan phylum from gondwanian soils

Cited by 43 publications

References 45 publications

The chimeric eukaryote: Origin of the nucleus from the karyomastigont in amitochondriate protists

The chimeric eukaryote: Origin of the nucleus from the karyomastigont in amitochondriate protists

Fine structure and biology of Cryothecomonas gen. nov. (Protista incertae sedis) from the ice biota

Eukaryotic systematics: a user's guide for cell biologists and parasitologists

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