Trichosphaerium

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Trichosphaerium
Trichosphaerium 1c microbiolres-14.png
Trichosphaerium sp. with dactylopodium (arrow)
Trichosphaerium 1d microbiolres-14.png
Trichosphaerium in its giant amoeba form
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Phylum: Amoebozoa
Class: Tubulinea
Clade: Corycidia
Order: Trichosida
Möbius, 1889
Family: Trichosphaeriidae
Sheehan & Banner, 1973
Genus: Trichosphaerium
Schneider, 1878
Synonyms
  • PontifexSchaeffer, 1926
  • AtrichosaCavalier-Smith, 2016 [1]

Trichosphaerium is a genus of amoebozoan protists that present extraordinary morphological transformations, both in size and shape, during their life cycle. They can present a test that may or may not be covered in spicules. They are related to the family Microcoryciidae, which contains other amoebae with tests, within the clade Corycidia of the phylum Amoebozoa.

Contents

Morphology

Trichosphaerium is a genus of amoebae characterized from other Amoebozoa by a multiporous test and a specialized non-motile pseudopodium, known as a dactylopodium, shaped like a digit. The dactylopodium is considered a sensory structure. Its morphology, behavior and life cycle are extraordinary in comparison with other protists. During its poorly understood life cycle, Trichosphaerium undergoes dramatic changes in shape and size. They can grow from as small as 10 µm to giant cell sizes of over 1 mm, observable by the naked eye. They can display such varied recognizable morphotypes that they can be easily mistaken with other species of amoebae. [2]

Immunocytochemistry staining of plasma membrane (red) and DNA (blue) of Trichosphaerium, showing various sizes of amoebae including a large amoeba cell with a large (polyploid) nucleus (arrow). Scale bar: 10 mm. Trichosphaerium 2c microbiolres-14.webp
Immunocytochemistry staining of plasma membrane (red) and DNA (blue) of Trichosphaerium, showing various sizes of amoebae including a large amoeba cell with a large (polyploid) nucleus (arrow). Scale bar: 10 μm.

Controversial reports describe an alternation of two trophozoite stages within its life cycle: the "schizont", an amoeba surrounded by a test covered in flexible spicules, and the "gamont", an amoeba surrounded by a more flexible and fibrous test without spicules. According to studies written by German protozoologist Fritz Schaudinn in 1899, the gamont stage produces flagellated gametes, which fuse into a zygote to generate the schizont stage. Although both morphotypes have been observed and kept in laboratory cultures over the decades, this alternation of generations has never been observed in them, which adds a layer of complexity to the unusual, poorly understood behavior of these amoebae. [2]

Systematics

Illustration of T. sieboldi FMIB 40813 Trichosphaerium sieboldi.jpeg
Illustration of T. sieboldi

Trichosphaerium is the sole accepted genus of the family Trichosphaeriidae (sometimes written as Trichosidae) [3] and the order Trichosida. [1] [4] The phylogenetic placement of Trichosphaerium has been controversial, [2] but most recent studies place it within the class Tubulinea of the phylum Amoebozoa. [1] [5] In particular, since 2017, phylogenomic analyses of Amoebozoa recover a clade known as Corycidia, at the base of Tubulinea, containing both Trichosphaerium and amoebae of the family Microcoryciidae together. [4] [6]

Synonyms

In 2016, American protozoologist Thomas Cavalier-Smith described the genus Atrichosa to comprise an undescribed species of Trichosphaerium, after considering that the type strain of this species does not belong to the genus Trichosphaerium but to a distinct, yet related, organism. [1] This change, however, was not accepted by the 2019 revision of eukaryotic classification, where Atrichosa is considered a junior synonym of Trichosphaerium "until the opposite is shown". [7] Another genus, Pontifex, is considered to be a synonym of Trichosphaerium, although with uncertainty. [1]

Species

Up to four species have been described within the genus, mainly based on the morphology of the spicules that cover their test. [2]

Related Research Articles

<span class="mw-page-title-main">Amoebozoa</span> Phylum of protozoans

Amoebozoa is a major taxonomic group containing about 2,400 described species of amoeboid protists, often possessing blunt, fingerlike, lobose pseudopods and tubular mitochondrial cristae. In traditional classification schemes, Amoebozoa is usually ranked as a phylum within either the kingdom Protista or the kingdom Protozoa. In the classification favored by the International Society of Protistologists, it is retained as an unranked "supergroup" within Eukaryota. Molecular genetic analysis supports Amoebozoa as a monophyletic clade. Modern studies of eukaryotic phylogenetic trees identify it as the sister group to Opisthokonta, another major clade which contains both fungi and animals as well as several other clades comprising some 300 species of unicellular eukaryotes. Amoebozoa and Opisthokonta are sometimes grouped together in a high-level taxon, variously named Unikonta, Amorphea or Opimoda.

<span class="mw-page-title-main">Lobosa</span> Phylum of protozoans

Lobosa is a taxonomic group of amoebae in the phylum Amoebozoa. Most lobosans possess broad, bluntly rounded pseudopods, although one genus in the group, the recently discovered Sapocribrum, has slender and threadlike (filose) pseudopodia. In current classification schemes, Lobosa is a subphylum, composed mainly of amoebae that have lobose pseudopods but lack cilia or flagella.

<i>Chaos</i> (genus) Genus of microscopic organisms

Chaos is a genus of single-celled amoeboid organisms in the family Amoebidae. The largest and most-known species, the so-called "giant amoeba", can reach lengths up to 5 mm, although most specimens fall between 1 and 3 mm.

The Vannellidae are a family of Amoebozoa, which are found in soil, fresh- and salt water. The most common genus is Vannella.

<i>Difflugia</i> Large genus of protists

Difflugia is the largest genus of Arcellinida, one of several groups of Tubulinea within the eukaryote supergroup Amoebozoa. Arcellinida species produce shells or tests from mineral particles or biogeonic elements and are thus commonly referred to as testate amoebae or shelled amoebae. Difflugia are particularly common in marshes and other freshwater habitats.

<span class="mw-page-title-main">Tubulinea</span> Class of protozoans

The Tubulinea are a major grouping of Amoebozoa, including most of the more familiar amoebae genera like Amoeba, Arcella, Difflugia and Hartmannella.

<span class="mw-page-title-main">Discosea</span> Class of amoebae

Discosea is a class of Amoebozoa, consisting of naked amoebae with a flattened, discoid body shape. Members of the group do not produce tubular or subcylindrical pseudopodia, like amoebae of the class Tubulinea. When a discosean is in motion, a transparent layer called hyaloplasm forms at the leading edge of the cell. In some discoseans, short "subpseudopodia" may be extended from this hyaloplasm, but the granular contents of the cell do not flow into these, as in true pseudopodia. Discosean amoebae lack hard shells, but some, like Cochliopodium and Korotnevella secrete intricate organic scales which may cover the upper (dorsal) surface of the cell. No species have flagella or flagellated stages of life.

<span class="mw-page-title-main">Archamoebae</span> Phylum of protists

The Archamoebae are a group of protists originally thought to have evolved before the acquisition of mitochondria by eukaryotes. They include genera that are internal parasites or commensals of animals. A few species are human pathogens, causing diseases such as amoebic dysentery. The other genera of archamoebae live in freshwater habitats and are unusual among amoebae in possessing flagella. Most have a single nucleus and flagellum, but the giant amoeba Pelomyxa has many of each.

<span class="mw-page-title-main">Eumycetozoa</span> Taxonomic group of slime molds

Eumycetozoa, or true slime molds, is a diverse group of protists that behave as slime molds and develop fruiting bodies, either as sorocarps or as sporocarps. It is a monophyletic group or clade within the phylum Amoebozoa that contains the myxogastrids, dictyostelids and protosporangiids.

<span class="mw-page-title-main">Protozoa</span> Single-celled eukaryotic organisms that feed on organic matter

Protozoa are a polyphyletic group of single-celled eukaryotes, either free-living or parasitic, that feed on organic matter such as other microorganisms or organic debris. Historically, protozoans were regarded as "one-celled animals".

<i>Cochliopodium</i> Genus of protozoans

Cochliopodium is a Himatismenida genus.

<i>Rhizamoeba</i> Genus of marine lobose amoebae

Rhizamoeba is a small genus of free-living marine naked lobose amoebae in the monotypic family Rhizamoebidae in the order Leptomyxida. It is most closely related to Leptomyxa and Flabellula, and some species have been moved to Leptomyxa due to molecular data.

<span class="mw-page-title-main">Thecofilosea</span> Class of single-celled organisms

Thecofilosea is a class of unicellular testate amoebae belonging to the phylum Cercozoa. They are amoeboflagellates, organisms with flagella and pseudopodia, distinguished from other cercozoa by their scale-lacking test composed of organic material. They are closely related to the Imbricatea, a group of testate amoebae with tests composed of inorganic silica scales.

<span class="mw-page-title-main">Testate amoebae</span>

Testate amoebae are a polyphyletic group of unicellular amoeboid protists, which differ from naked amoebae in the presence of a test that partially encloses the cell, with an aperture from which the pseudopodia emerge, that provides the amoeba with shelter from predators and environmental conditions.

<span class="mw-page-title-main">Vampyrellida</span> Order of single-celled organisms

The vampyrellids, colloquially known as vampire amoebae, are a group of free-living predatory amoebae classified as part of the lineage Endomyxa. They are distinguished from other groups of amoebae by their irregular cell shape with propensity to fuse and split like plasmodial organisms, and their life cycle with a digestive cyst stage that digests the gathered food. They appear worldwide in marine, brackish, freshwater and soil habitats. They are important predators of an enormous variety of microscopic organisms, from algae to fungi and animals. They are also known as aconchulinid amoebae.

<span class="mw-page-title-main">Amoeba</span> Polyphyletic group of unicellular eukaryotes with the ability to shapeshift

An amoeba, often called an amoeboid, is a type of cell or unicellular organism with the ability to alter its shape, primarily by extending and retracting pseudopods. Amoebae do not form a single taxonomic group; instead, they are found in every major lineage of eukaryotic organisms. Amoeboid cells occur not only among the protozoa, but also in fungi, algae, and animals.

Cutosea is a small group of marine amoeboid protists proposed in 2016. It is a monotypic class of Amoebozoa containing the order Squamocutida. Cutosean organisms are characterized by a cell coat of microscales separated from the cell membrane. Three genera, Armaparvus, Sapocribrum and Squamamoeba, belong to this group, distributed in two families.

<span class="mw-page-title-main">Cryptodifflugiidae</span> Family of testate amoebae

Cryptodifflugiidae is a family of arcellinid testate amoebae.

<span class="mw-page-title-main">Evosea</span> Group of amoebae

Evosea is a diverse clade of amoeboid protists discovered through molecular analyses. Along with Tubulinea and Discosea, Evosea is one of the three major groups within Amoebozoa, an important clade of eukaryotic organisms. It contains unicellular organisms that display a wide variety of life cycles and cell shapes, including amoebae, flagellates and different kinds of slime molds.

<span class="mw-page-title-main">Corycidia</span> Group of amoebae

Corycidia is a clade of amoeboid protists within the eukaryotic supergroup Amoebozoa. It contains all amoebae of the families Microcoryciidae, which was previously regarded as Arcellinida, and Trichosphaeriidae, which contains the sole genus Trichosphaerium.

References

  1. 1 2 3 4 5 6 Cavalier-Smith T, Chao EE, Lewis R (June 2016). "187-gene phylogeny of protozoan phylum Amoebozoa reveals a new class (Cutosea) of deep-branching, ultrastructurally unique, enveloped marine Lobosa and clarifies amoeba evolution". Molecular Phylogenetics and Evolution. 99: 275–296. doi: 10.1016/j.ympev.2016.03.023 . PMID   27001604.
  2. 1 2 3 4 Tekle, Yonas I.; Tran, Hanh; Wang, Fang; Singla, Mandakini; Udu, Isimeme (2023). "Omics of an Enigmatic Marine Amoeba Uncovers Unprecedented Gene Trafficking from Giant Viruses and Provides Insights into Its Complex Life Cycle". Microbiology Research. 14 (2): 656–672. doi: 10.3390/microbiolres14020047 . PMC   10521059 . PMID   37752971.
  3. Adl SM, Simpson AG, Farmer MA, et al. (2005). "The new higher level classification of eukaryotes with emphasis on the taxonomy of protists" (PDF). The Journal of Eukaryotic Microbiology. 52 (5): 399–451. doi: 10.1111/j.1550-7408.2005.00053.x . PMID   16248873.
  4. 1 2 Kang, Seungho; Tice, Alexander K; Spiegel, Frederick W; Silberman, Jeffrey D; Pánek, Tomáš; Čepička, Ivan; Kostka, Martin; Kosakyan, Anush; Alcântara, Daniel M C; Roger, Andrew J; Shadwick, Lora L; Smirnov, Alexey; Kudryavtsev, Alexander; Lahr, Daniel J G; Brown, Matthew W (September 2017). "Between a Pod and a Hard Test: The Deep Evolution of Amoebae". Molecular Biology and Evolution. 34 (9): 2258–2270. doi:10.1093/molbev/msx162. PMC   5850466 . PMID   28505375.
  5. Tekle YI, Wood FC (September 2017). "Longamoebia is not monophyletic: Phylogenomic and cytoskeleton analyses provide novel and well-resolved relationships of amoebozoan subclades". Molecular Phylogenetics and Evolution. 114: 249–260. doi: 10.1016/j.ympev.2017.06.019 . PMID   28669813.
  6. Tekle YI, Wang F, Wood FC, Anderson OR, Smirnov A (2022). "New insights on the evolutionary relationships between the major lineages of Amoebozoa". Sci Rep. 12 (11173): 11173. Bibcode:2022NatSR..1211173T. doi:10.1038/s41598-022-15372-7. PMC   9249873 . PMID   35778543. S2CID   247231712.
  7. 1 2 Adl SM, Bass D, Lane CE, Lukeš J, Schoch CL, Smirnov A, Agatha S, Berney C, Brown MW, Burki F, Cárdenas P, Čepička I, Chistyakova L, del Campo J, Dunthorn M, Edvardsen B, Eglit Y, Guillou L, Hampl V, Heiss AA, Hoppenrath M, James TY, Karnkowska A, Karpov S, Kim E, Kolisko M, Kudryavtsev A, Lahr DJG, Lara E, Le Gall L, Lynn DH, Mann DG, Massana R, Mitchell EAD, Morrow C, Park JS, Pawlowski JW, Powell MJ, Richter DJ, Rueckert S, Shadwick L, Shimano S, Spiegel FW, Torruella G, Youssef N, Zlatogursky V, Zhang Q (2019). "Revisions to the Classification, Nomenclature, and Diversity of Eukaryotes". Journal of Eukaryotic Microbiology. 66 (1): 4–119. doi:10.1111/jeu.12691. PMC   6492006 . PMID   30257078.
  8. Angell, Robert W. (1975). "Structure of Trichosphaerium micrum sp. n.". The Journal of Protozoology. 22: 18–22. doi:10.1111/j.1550-7408.1975.tb00937.x.
  9. Angell, Robert W. (1976). "Observations on Trichosphaerium platyxyrum sp. n.". The Journal of Protozoology. 23 (3): 357–364. doi:10.1111/j.1550-7408.1976.tb03788.x.