Parabasalia

Čepička, Ivan; Dolan, Michael F.; Gile, Gillian H.

doi:10.1007/978-3-319-28149-0_9

Cited by 15 publications

(28 citation statements)

References 141 publications

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“…The taxonomy of Parabasalia has recently been updated to reflect their molecular phylogeny ( 30 ). Based on this taxonomic revision, SSU rRNA sequences are classified into eight well-accepted major groups: Cristamonadida, Hypotrichomonadida, Spirotrichonymphida, Trichomonadida, Honigbergiellida, Tritrichomonadida, Trichonymphida and Lophomonadida.…”

Section: Resultsmentioning

confidence: 99%

OUP accepted manuscript

et al. 2020

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The small subunit ribosomal RNA (SSU rRNA) gene is a widely used molecular marker to study the diversity of life. Sequencing of SSU rRNA gene amplicons has become a standard approach for the investigation of the ecology and diversity of microbes. However, a well-curated database is necessary for correct classification of these data. While available for many groups of Bacteria and Archaea, such reference databases are absent for most eukaryotes. The primary goal of the EukRef project (eukref.org) is to close this gap and generate well-curated reference databases for major groups of eukaryotes, especially protists. Here we present a set of EukRef-curated databases for the excavate protists—a large assemblage that includes numerous taxa with divergent SSU rRNA gene sequences, which are prone to misclassification. We identified 6121 sequences, 625 of which were obtained from cultures, 3053 from cell isolations or enrichments and 2419 from environmental samples. We have corrected the classification for the majority of these curated sequences. The resulting publicly available databases will provide phylogenetically based standards for the improved identification of excavates in ecological and microbiome studies, as well as resources to classify new discoveries in excavate diversity.

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Section: Resultsmentioning

confidence: 99%

OUP accepted manuscript

et al. 2020

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“…Trichomonads (Excavata: Parabasalia) are anaerobic, flagellated protists, which commonly inhabit the digestive, oral, or urogenital tract of various invertebrate and vertebrate hosts. Most of them are beneficial mutualists or commensals of termites, while only a minority has been described among vertebrates (Čepička et al ., 2017). The trichomonads that inhabit the intestines of vertebrates are mostly considered commensals, however, notable exceptions exist including Histomonas meleagridis , an important pathogen of poultry, and Dientamoeba fragilis , whose pathogenic potential for humans is debated (Wong et al ., 2018).…”

Section: Introductionmentioning

confidence: 99%

“…Tai et al ., 2015). In contrast, it has been shown that some trichomonad species from vertebrates can infect a broad range of hosts (for examples see Čepička et al ., 2017). Interestingly, several bird-infecting trichomonads of the genus Trichomonas were recognized as close relatives of pathogenic trichomonads in humans including T. vaginalis and T. tenax (Maritz et al ., 2014).…”

Section: Introductionmentioning

confidence: 99%

Sympatric western lowland gorillas, central chimpanzees and humans are infected with different trichomonads

Petrželková¹,

Smejkalová²,

Céza³

et al. 2019

Parasitology

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We investigated intestinal trichomonads in western lowland gorillas, central chimpanzees and humans cohabiting the forest ecosystem of Dzanga-Sangha Protected Area in Central African Republic, using the internal transcribed spacer (ITS) region and SSU rRNA gene sequences. Trichomonads belonging to the genus Tetratrichomonas were detected in 23% of the faecal samples and in all host species. Different hosts were infected with different genotypes of Tetratrichomonas. In chimpanzees, we detected tetratrichomonads from ‘novel lineage 2’, which was previously reported mostly in captive and wild chimpanzees. In gorillas, we found two different genotypes of Tetratrichomonas. The ITS region sequences of the more frequent genotype were identical to the sequence found in a faecal sample of a wild western lowland gorilla from Cameroon. Sequences of the second genotype from gorillas were almost identical to sequences previously obtained from an anorexic French woman. We provide the first report of the presence of intestinal tetratrichomonads in asymptomatic, apparently healthy humans. Human tetratrichomonads belonged to the lineage 7, which was previously reported in domestic and wild pigs and a domestic horse. Our findings suggest that the ecology and spatial overlap among hominids in the tropical forest ecosystem has not resulted in exchange of intestinal trichomonads among these hosts.

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“…A prominent feature uniting Cryptocercus with the termites is a symbiotic relationship with single-celled anaerobic eukaryotes living in the enlarged hindgut paunch of the insects. These gut protists fall into two main groups traditionally known as flagellates—the Phylum Parabasalia and the Order Oxymonadida (Phylum Preaxostyla) [ 6 ], with the former historically divided into the trichomonads and hypermastigotes. Nearly 450 distinct flagellate species have been described in the termite and Cryptocercus hosts that have been investigated (see [ 7 , 8 ] for a catalogue of those reported).…”

Section: Introductionmentioning

confidence: 99%

What Kills the Hindgut Flagellates of Lower Termites during the Host Molting Cycle?

Nalepa

2017

Microorganisms

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Subsocial wood feeding cockroaches in the genus Cryptocercus, the sister group of termites, retain their symbiotic gut flagellates during the host molting cycle, but in lower termites, closely related flagellates die prior to host ecdysis. Although the prevalent view is that termite flagellates die because of conditions of starvation and desiccation in the gut during the host molting cycle, the work of L.R. Cleveland in the 1930s through the 1960s provides a strong alternate hypothesis: it was the changed hormonal environment associated with the origin of eusociality and its concomitant shift in termite developmental ontogeny that instigates the death of the flagellates in termites. Although the research on termite gut microbial communities has exploded since the advent of modern molecular techniques, the role of the host hormonal environment on the life cycle of its gut flagellates has been neglected. Here Cleveland’s studies are revisited to provide a basis for re-examination of the problem, and the results framed in the context of two alternate hypotheses: the flagellate symbionts are victims of the change in host social status, or the flagellates have become incorporated into the life cycle of the eusocial termite colony. Recent work on parasitic protists suggests clear paths for exploring these hypotheses and for resolving long standing issues regarding sexual-encystment cycles in flagellates of the Cryptocercus-termite lineage using molecular methodologies, bringing the problem into the modern era.

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Parabasalia

Cited by 15 publications

References 141 publications

OUP accepted manuscript

OUP accepted manuscript

Sympatric western lowland gorillas, central chimpanzees and humans are infected with different trichomonads

What Kills the Hindgut Flagellates of Lower Termites during the Host Molting Cycle?

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