Arcellinida

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Arcellinid testate amoebae or Arcellinida,[1]Arcellacean[2] or lobose testate amoebae[3] are single-celled protists partially enclosed in a simple test (shell).

Arcellinid testate amoebae are commonly found in soils, leaf litter, peat bogs and near/in fresh water.[1] They use their pseudopodia, a temporary cell extension, for moving and taking in food. Like most amoebae, they are generally believed to reproduce asexually via binary fission. However a recent review suggests that sexual recombination may be the rule rather than the exception in amoeboid protists in general, including the Arcellinid testate amoebae.[4]

Morphology

Representation of an arcellinid
  1. Test, cemented sand, diatom frustules
  2. Contractile vacuole, regulates the quantity of water inside a cell
  3. Mitochondrion; creates ATP (energy) for the cell (flat cristae)
  4. Nucleolus
  5. Golgi apparatus, packages proteins
  6. Endoplasmic reticulum, the transport network for molecules going to specific parts of the cell
  7. Digestive Vacuole
  8. Lysosome, holds enzymes
  9. Phagosome, vesicle formed around a particle (prey not to scale)
  10. Xenosome, bacterium living inside cytoplasm
  11. Vesicles
  12. Lobopodia, a pseudopod or arm-like projection made of cytoplasm
  13. Prey (not to scale)

Arcellinida always have a shell or test. The tests lie outside the cell membrane and consist of organic or mineral materials that are either secreted or incorporate external particles. The test has a single main opening.[5]

Simple tests are made by secretion (autogenous tests), agglutination of foreign material (xenogenous tests), or sometimes a combination of both. Past environmental changes can be determined by analysing the composition of fossil tests, including the reconstruction of past climate change.[1] Testate amoebae species have been used to reconstruct hydrological changes over the late Holocene, as a result of individual species possessing a narrow tolerance for ecohydrological conditions such as water-table depth or pH.[6]

Evolutionary history

Fossils of arcellinid testate amoebae date back to the Tonian stage of the Proterozoic, around 789-759 million years ago. The fossils indicate that by 730 million years ago, arcellinids had already diversified into major lineages.[7]

Testate amoebae are theorized to be mostly polyphyletic (coming from more than one ancestral type), but testaceafilosea, one group of testate amoebae, are theorized to be monophyletic. Ancient tests of terrestrial fauna are commonly found in fossilized amber,[8] although mid-Cretaceous testate amoeba (i.e., Difflugia, Cucurbitella) have been found in ancient lake sediments.[9] It is likely that the group has evolved minimally over the course of the Phanerozoic.

Classification

Phylogeny of Arcellinida in 2019[10]
Arcellinida
Phylogeny of Arcellinida in 2022[11]
Arcellinida

The classification of Arcellinida, as of 2019:[12][5][10]

Arcellinida incertae sedis:

References

  1. 123http://www.microscopy-uk.org.uk/mag/artjun03/gsamoebae.html Testate amoebae, peat bogs and past climates. accessed 16 march 2007
  2. ↑Identification key for holocene lacustrine arcellacean (thecamoebian) taxaArchived December 4, 2008, at the Wayback Machine
  3. ↑Lara E, Heger TJ, Ekelund F, Lamentowicz M, Mitchell EA (April 2008). "Ribosomal RNA genes challenge the monophyly of the Hyalospheniidae (Amoebozoa: Arcellinida)". Protist. 159 (2): 165–76. doi:10.1016/j.protis.2007.09.003. PMID 18023614.
  4. ↑Lahr DJ, Parfrey LW, Mitchell EA, Katz LA, Lara E (2011). "The chastity of amoebae: re-evaluating evidence for sex in amoeboid organisms". Proceedings of the Royal Society B: Biological Sciences. 278 (1715): 2081–2090. doi:10.1098/rspb.2011.0289. PMC 3107637. PMID 21429931.
  5. 12Adl SM, Simpson AG, Lane CE, Lukeš J, Bass D, Bowser SS, Brown MW, Burki F, Dunthorn M, Hampl V, Heiss A, Hoppenrath M, Lara E, le Gall L, Lynn DH, McManus H, Mitchell EA, Mozley-Stanridge SE, Parfrey LW, Pawlowski J, Rueckert S, Shadwick L, Schoch CL, Smirnov A, Spiegel FW (2012). "The Revised Classification of Eukaryotes". Journal of Eukaryotic Microbiology. 59 (5): 429–514. doi:10.1111/j.1550-7408.2012.00644.x. PMC 3483872. PMID 23020233.
  6. ↑Woodland, Wendy, A. (1998). "Quantitative estimates of water tables and soil moisture in Holocene peatlands from testate amoebae". The Holocene. 8 (3): 261–273. doi:10.1191/095968398667004497. S2CID 128897334.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  7. ↑Lahr, Daniel J.G.; Kosakyan, Anush; Lara, Enrique; Mitchell, Edward A.D.; Morais, Luana; Porfirio-Sousa, Alfredo L.; Ribeiro, Giulia M.; Tice, Alexander K.; Pánek, Tomáš; Kang, Seungho; Brown, Matthew W. (2019-03-18). "Phylogenomics and Morphological Reconstruction of Arcellinida Testate Amoebae Highlight Diversity of Microbial Eukaryotes in the Neoproterozoic". Current Biology. 29 (6): 991–1001.e3. doi:10.1016/j.cub.2019.01.078. hdl:10261/240246. ISSN 0960-9822. PMID 30827918. S2CID 72333352.
  8. ↑Schmidt, A.R.; Ragazzi, E.; Coppellotti, O.; Roghi, G. (2006). "A microworld in Triassic amber". Nature. 444 (7121): 835. doi:10.1038/444835a. PMID 17167469.
  9. ↑Hengstum, Van; Reinhardt, E.G.; Medioli, F.S.; Grocke, D.R. (2007). "Exceptionally preserved late albian (Cretaceous) Arcellaceans (Thecamoebians) from the Dakota Formation near Lincoln, Nebraska"(PDF). Journal of Foraminiferal Research. 37 (4): 300–308. doi:10.2113/gsjfr.37.4.300.
  10. 12Lahr, Daniel J.G.; Kosakyan, Anush; Lara, Enrique; Mitchell, Edward A.D.; Morais, Luana; Porfirio-Sousa, Alfredo L.; Ribeiro, Giulia M.; Pánek, Tomáš; Kang, Seungho; Brown, Matthew W. (2019). "Phylogenomics and Morphological Reconstruction of Arcellinida Testate Amoebae Highlight Diversity of Microbial Eukaryotes in the Neoproterozoic". Current Biology. 29 (6): 991–1001. doi:10.1016/j.cub.2019.01.078. hdl:11380/1301486. PMID 30827918.
  11. ↑González-Miguéns, Rubén; Todorov, Milcho; Blandenier, Quentin; Duckert, Clément; Porfirio-Sousa, Alfredo L.; Ribeiro, Giulia M.; Ramos, Diana; Lahr, Daniel J.G.; Buckley, David; Lara, Enrique (2022). "Deconstructing Difflugia: The tangled evolution of lobose testate amoebae shells (Amoebozoa: Arcellinida) illustrates the importance of convergent evolution in protist phylogeny". Molecular Phylogenetics and Evolution. 175 107557. doi:10.1016/j.ympev.2022.107557. hdl:10261/281619. ISSN 1055-7903. PMID 35777650.
  12. ↑Ralf Meisterfeld: Arcellinida, In: John J. Lee, Gordon F. Leedale, Phyllis Bradbury (Hrsg.): Illustrated Guide to the Protozoa, 2nd Edition. Vol. 2, Society of Protozoologists, Lawrence, Kansas 2000, ISBN 1-891276-23-9, pp. 827-860
  • ISTAR, the International Society for Testate Amoeba Research
  • Tree of Life: Arcellinida
  • An article by G. T. Swindles
  • Protozoa: The testate amoebae
  • BioImages: The Virtual Field-Guide (UK) - TESTACEA (Testate amoebae)
  • Pictures of testate amoebae
  • The Cushman Foundation Thecamoebian Page