Amoeboflagellate

An amoeboflagellate (pl. amoeboflagellates) is any eukaryotic organism capable of behaving as an amoeba and as a flagellate at some point during their life cycle. Amoeboflagellates present both pseudopodia and at least one flagellum, often simultaneously.^[1][2]

The heterolobosean pathogen Naegleria fowleri can behave as an amoeba (center) or as a flagellate (right).

Occurrence

The amoeboflagellate cell type has been acquired numerous independent times across the evolution of protists (i.e. primarily unicellular eukaryotes that are not plants, fungi or animals).^[3] Some examples of protist phyla with amoeboflagellate body types are:

• Cercozoa contains various examples of amoeboflagellates with filose pseudopods, thread-like cell projections also known as filopodia. The cercomonads, glissomonads and paracercomonads behave as amoeboflagellates with two flagella throughout the majority of their life cycle,^[2][4] and are essential predators of the soil microbiome.^[5] Among the more basal Cercozoa is Reticulamoeba, an amoeboflagellate with reticulose pseudopods (reticulopodia), filopodia that join into a net-like structure.^[6]

• Amoebozoa contains several groups of amoeboflagellates with one^[7] or two flagella^[8] and lobose pseudopods, which are rounder and more blunt-ended than filopodia. Among them are the myxogastrids, a group of slime molds that behave as amoeboflagellates in various stages of their life cycle.^[9] Many species of Archamoebae, a more basal group, are anaerobic amoeboflagellates.^[10] Other examples are the dictyostelians, another group of slime molds,^[11] and the closely related varioseans, such as Phalansterium.^[7]

• Breviatea, a small class^[a] related to animals, fungi and amoebozoans, is composed of anaerobic amoeboflagellates with two flagella.^[13][14]

• Percolozoa contains amoeboflagellates with lobose pseudopods, but are differentiated by their flat mitochondrial cristae, not tubular as in Amoebozoa.^[7][15] A popular example is the genus Naegleria, whose members can change shape between an amoeba and a flagellate.^[1]

The choanoflagellate Salpingoeca rosetta can switch between a swimming (flagellate) stage and a crawling (amoeboid) stage when subjected to a confined space.^[3]

The amoeboflagellate phenotype is present in numerous protists that have a crucial phylogenetic position near the origin of animals and fungi, within the vast clade known as Opisthokonta. It has been described in choanoflagellates such as Salpingoeca, filastereans such as Pigoraptor, and even some early-branching fungi such as Sanchytrium,^[16] but it is absent in animals.^[3] The two species of Pluriformea have a wide range of cell types, from cellular aggregations to amoeboflagellates.^[17]

Notes

1. This class belongs to a paraphyletic phylum that is in disuse, known as Apusozoa.^[12] Although not a phylum itself, it is listed here with other phyla due to comprising an independent clade of organisms.

References

1. Johan F De Jonckheere (6 August 2011). "Origin and evolution of the worldwide distributed pathogenic amoeboflagellate Naegleria fowleri". Infection, Genetics and Evolution. 11 (7): 1520–1528. doi:10.1016/J.MEEGID.2011.07.023. ISSN 1567-1348. PMID 21843657. Wikidata Q37917917.
2. Alexander P. Myl'nikov; Serguei A. Karpov (2004). "Review of diversity and taxonomy of cercomonads" (PDF). Protistology. 3 (4): 201–217. ISSN 1680-0826. Wikidata Q124459772.
3. Thibaut Brunet; Marvin Albert; William Roman; Maxwell C Coyle; Danielle C Spitzer; Nicole King (15 January 2021). "A flagellate-to-amoeboid switch in the closest living relatives of animals". eLife. 10. doi:10.7554/ELIFE.61037. ISSN 2050-084X. PMC 7895527. PMID 33448265. Wikidata Q105870433.
4. Sebastian Hess; Michael Melkonian (21 July 2014). "Ultrastructure of the Algivorous Amoeboflagellate Viridiraptor invadens (Glissomonadida, Cercozoa)". Protist. 165 (5): 605–635. doi:10.1016/J.PROTIS.2014.07.004. ISSN 1434-4610. PMID 25150610. Wikidata Q42464422.
5. Anna Maria Fiore-Donno; Tim Richter-Heitmann; Florine Degrune; et al. (11 June 2019). "Functional Traits and Spatio-Temporal Structure of a Major Group of Soil Protists (Rhizaria: Cercozoa) in a Temperate Grassland". Frontiers in Microbiology. 10: 1332. doi:10.3389/FMICB.2019.01332. ISSN 1664-302X. PMC 6579879. PMID 31244819. Wikidata Q64891960.
6. David Bass; Akinori Yabuki; Sébastien Santini; Sarah Romac; Cédric Berney (4 December 2012). "Reticulamoeba is a long-branched Granofilosean (Cercozoa) that is missing from sequence databases". PLOS One. 7 (12): e49090. Bibcode:2012PLoSO...749090B. doi:10.1371/JOURNAL.PONE.0049090. ISSN 1932-6203. PMC 3514243. PMID 23226495. Wikidata Q34506390.
7. Thomas Cavalier-Smith; Ema E.-Y. Chao; Brian Oates (May 2004). "Molecular phylogeny of Amoebozoa and the evolutionary significance of the unikont Phalansterium". European Journal of Protistology. 40 (1): 21–48. doi:10.1016/J.EJOP.2003.10.001. ISSN 0932-4739. Wikidata Q29399107.
8. Emmo Hamann; Harald Gruber-Vodicka; Manuel Kleiner; et al. (9 June 2016). "Environmental Breviatea harbour mutualistic Arcobacter epibionts". Nature. 534 (7606): 254–8. doi:10.1038/NATURE18297. ISSN 1476-4687. PMC 4900452. PMID 27279223. Wikidata Q28828264.
9. Jim Clark; Edward F. Haskins (2016). "Mycosphere Essays 3. Myxomycete spore and amoeboflagellate biology: a review". Mycosphere. 7 (2): 86–101. doi:10.5943/MYCOSPHERE/7/2/1. ISSN 2077-7019. Wikidata Q117487619.
10. Irina A. Milyutina; Vladimir V. Aleshin; Kirill A. Mikrjukov; OIga S. Kedrova; Nikolai B. Petrov (1 July 2001). "The unusually long small subunit ribosomal RNA gene found in amitochondriate amoeboflagellate Pelomyxa palustris: its rRNA predicted secondary structure and phylogenetic implication". Gene. 272 (1–2): 131–139. doi:10.1016/S0378-1119(01)00556-X. ISSN 0378-1119. PMID 11470518. Wikidata Q48352141.
11. Koryu Kin; Pauline Schaap (27 March 2021). "Evolution of Multicellular Complexity in The Dictyostelid Social Amoebas". Genes. 12 (4): 487. doi:10.3390/GENES12040487. ISSN 2073-4425. PMC 8067170. PMID 33801615. Wikidata Q124470705.
12. Jordi Paps; Luis A Medina-Chacón; Wyth Marshall; Hiroshi Suga; Iñaki Ruiz-Trillo (18 October 2012). "Molecular phylogeny of unikonts: new insights into the position of apusomonads and ancyromonads and the internal relationships of opisthokonts". Protist. 164 (1): 2–12. doi:10.1016/J.PROTIS.2012.09.002. ISSN 1434-4610. PMC 4342546. PMID 23083534. Wikidata Q34307204.
13. Marianne A Minge; Jeffrey D Silberman; Russell J S Orr; Thomas Cavalier-Smith; Kamran Shalchian-Tabrizi; Fabien Burki; Asmund Skjaeveland; Kjetill S Jakobsen (22 February 2009). "Evolutionary position of breviate amoebae and the primary eukaryote divergence". Proceedings of the Royal Society B. 276 (1657): 597–604. doi:10.1098/RSPB.2008.1358. ISSN 0962-8452. PMC 2660946. PMID 19004754. Wikidata Q24652846.
14. Thomas Cavalier-Smith; Ema E Chao; Elizabeth A Snell; Cédric Berney; Anna Maria Fiore-Donno; Rhodri Lewis (23 August 2014). "Multigene eukaryote phylogeny reveals the likely protozoan ancestors of opisthokonts (animals, fungi, choanozoans) and Amoebozoa". Molecular Phylogenetics and Evolution. 81: 71–85. doi:10.1016/J.YMPEV.2014.08.012. ISSN 1055-7903. PMID 25152275. Wikidata Q34434820.
15. C A Broers; C K Stumm; G D Vogels; G Brugerolle (1 June 1990). "Psalteriomonas lanterna gen. nov., sp. nov., a free-living amoeboflagellate isolated from freshwater anaerobic sediments". European Journal of Protistology. 25 (4): 369–380. doi:10.1016/S0932-4739(11)80130-6. ISSN 0932-4739. PMID 23196051. Wikidata Q30579184.
16. Luis Javier Galindo; Purificación López-García; Guifré Torruella; Sergey Karpov; David Moreira (17 August 2021). "Phylogenomics of a new fungal phylum reveals multiple waves of reductive evolution across Holomycota". Nature Communications. 12 (1). doi:10.1038/S41467-021-25308-W. ISSN 2041-1723. PMC 8371127. PMID 34404788. Wikidata Q113186376.
17. Elisabeth Hehenberger; Denis Tikhonenkov; Martin Kolisko; Javier del Campo; Anton S Esaulov; Alexander P Mylnikov; Patrick J Keeling (15 June 2017). "Novel Predators Reshape Holozoan Phylogeny and Reveal the Presence of a Two-Component Signaling System in the Ancestor of Animals". Current Biology. 27 (13): 2043-2050.e6. doi:10.1016/J.CUB.2017.06.006. ISSN 0960-9822. PMID 28648822. Wikidata Q40146126.