Amoebidium

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Amoebidium
Amoebidium parasiticum.jpg
Amoebidium parasiticum
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Class: Ichthyosporea
Order: Ichthyophonida
Family: Amoebidiaceae
Genus: Amoebidium
Cienkowski, 1861 [1]
Type species
Amoebidium parasiticum
Cienkowski 1861
Species [2] [3] [4]
  • A. appalachense
  • A. australiense
  • A. colluviei
  • A. parasiticum
  • A. recticola

Amoebidium is a genus of unicellular, symbiotic eukaryotes in the Opisthokont group Mesomycetozoea, [5] family Amoebidiidae. [6] [7] Amoebidium species attach to the exoskeleton of freshwater aquatic arthropods such as midge larvae and water fleas ( Daphnia ). [8] The type species is Amoebidium parasiticum , [1] which is also one of the only species to be cultured axenically. [9]

Contents

Etymology

Derived from the word "amoeba" to refer to the amoeba-like dispersal cells formed during some stages of the life cycle. [1]

Description

Amoebidium species are single-celled, cigar-shaped or tubular in vegetative growth form (= thallus), and attach to the exoskeleton of various freshwater arthropod hosts (Crustaecea or Insecta) by means of a secreted, glue-like basal holdfast. [1] [8] The thalli are coenocytic (i.e. lack divisions within the cell) and are unbranched. Sexual reproduction is unknown. Asexual reproduction may proceed along two different routes: 1) the entire content of the cell divides into elongated, uninucleate spores (known as sporangiospores or endospores) with the cell wall breaking apart to release the spores or 2) the entire content of the cell divides to produce teardrop-shaped, motile amoeboid cells that disperse for a short time, then encyst and produce spores from the cyst (called cystospores). [8] [10] [11]

Species

There are currently five species that have been named [8] and are differentiated based on the size and shape of the thalli, spores, and dispersal amoebae. Amoebidium parasiticum is the most commonly encountered species in field collections, and appears to have a cosmopolitan distribution with collections from the Czech Republic, Denmark, England, France, Israel, Japan, the Philippines, Poland, Singapore, Spain, Tunisia, and the United States including Puerto Rico. [8] It has also been found in association with a variety of hosts including copepods, amphipods, isopods, mayfly nymphs, and black fly and midge larvae. The other four species ( A. appalachense , [12] A. australiense , [13] A. colluviei , [14] and A. recticola [15] ) have been collected from limited geographic areas, but it is unclear whether these species truly have a limited distribution or if the observed distribution is an artifact of limited sampling. [16] For example, A. recticola has not been reported in the literature since 1920 [17] and was originally collected from Daphnia living in a reptile tank at the Paris Museum, France. [15]

Culturing

Amoebidium parasiticum was the first trichomycete (a group of microscopic fungi and protists found in symbiotic association with aquatic arthropods) to be obtained in axenic culture, [9] allowing for detailed studies of its nutritional requirements, [18] cell wall composition, [19] and conditions that induce amoebagenesis [20] (formation and release of the dispersal amoebae) as well as providing pure tissue for DNA extraction. Several important characteristics were discovered from these studies. Firstly, Amoebidium was originally tentatively placed within kingdom Fungi, but its actual relatedness to fungi was questioned due to the formation of amoeboid cells (a character not observed among fungi). [8] When the cell wall composition of A. parasiticum was analyzed, there was no chitin or cellulose detected, a result that supported the non-relatedness of Amoebidium to fungi. [19] Secondly, experimentation on the nutritional requirements of A. parasiticum lead to the development of various media recipes that enabled the culturing of other trichomycete species. [8] Thirdly, researchers had noted that amoebagenesis appeared to be triggered by ecdysis or death of the host arthropod based on their observations during dissections. [21] Experiments with A. parasiticum cultures supported these observations by showing that amoebagenesis could be induced by incubating Amoebidium thalli with a homogenate of the host (Daphnia) supplemented with various combinations of amino acids and vitamins. [20] [22] Finally, collection of trichomycete DNA for molecular phylogenetic analysis is very challenging due to contaminating DNA from the host, bacteria, and other symbionts and food items residing in the host gut at the time of dissection. Therefore, axenic cultures of trichomycetes are highly valuable for obtaining pure DNA samples. As a result, the phylogenetic position of A. parasiticum was finally resolved in 2000 when molecular phylogenetic analyses [23] [24] showed that it clearly was not related to fungi, but instead belonged with a group of protists in the Mesomycetozoea (at the time referred to as the DRIP clade). Amoebidiumappalachense was also obtained in axenic culture, and subsequent molecular analyses supported its relationship with A. parasiticum and other Mesomycetozoea [7] .

Related Research Articles

<span class="mw-page-title-main">Opisthokont</span> Group of eukaryotes which includes animals and fungi, among other groups

The opisthokonts are a broad group of eukaryotes, including both the animal and fungus kingdoms. The opisthokonts, previously called the "Fungi/Metazoa group", are generally recognized as a clade. Opisthokonts together with Apusomonadida and Breviata comprise the larger clade Obazoa.

<span class="mw-page-title-main">Ichthyosporea</span> Clade of eukaryote organisms

The Ichthyosporea are a small group of Opisthokonta in Eukaryota, mostly parasites of fish and other animals.

<span class="mw-page-title-main">Glomeromycota</span> Phylum of fungi

Glomeromycota are one of eight currently recognized divisions within the kingdom Fungi, with approximately 230 described species. Members of the Glomeromycota form arbuscular mycorrhizas (AMs) with the thalli of bryophytes and the roots of vascular land plants. Not all species have been shown to form AMs, and one, Geosiphon pyriformis, is known not to do so. Instead, it forms an endocytobiotic association with Nostoc cyanobacteria. The majority of evidence shows that the Glomeromycota are dependent on land plants for carbon and energy, but there is recent circumstantial evidence that some species may be able to lead an independent existence. The arbuscular mycorrhizal species are terrestrial and widely distributed in soils worldwide where they form symbioses with the roots of the majority of plant species (>80%). They can also be found in wetlands, including salt-marshes, and associated with epiphytic plants.

<span class="mw-page-title-main">Laboulbeniomycetes</span> Class of fungi

The Laboulbeniomycetes are a unique group of fungi that are obligatorily associated with arthropods, either as external parasites or for dispersal (Pyxidiophorales).

<span class="mw-page-title-main">Laboulbeniales</span> Order of fungi

The Laboulbeniales is an order of Fungi within the class Laboulbeniomycetes. They are also known by the colloquial name beetle hangers or labouls. The order includes around 2,325 species of obligate insect ectoparasites that produce cellular thalli from two-celled ascospores. Of the described Laboulbeniales, Weir and Hammond 1997 find 80% to be from Coleoptera and the next largest group to be the 10% from Diptera. Recently, the genus Herpomyces, traditionally considered a basal member of Laboulbeniales, was transferred to the order Herpomycetales based on molecular phylogenetic data. Laboulbeniales typically do not kill their hosts, although they may impair host fitness if the parasite density is high.

<span class="mw-page-title-main">Blastocladiomycota</span> Phylum of flagellated fungi

Blastocladiomycota is one of the currently recognized phyla within the kingdom Fungi. Blastocladiomycota was originally the order Blastocladiales within the phylum Chytridiomycota until molecular and zoospore ultrastructural characters were used to demonstrate it was not monophyletic with Chytridiomycota. The order was first erected by Petersen for a single genus, Blastocladia, which was originally considered a member of the oomycetes. Accordingly, members of Blastocladiomycota are often referred to colloquially as "chytrids." However, some feel "chytrid" should refer only to members of Chytridiomycota. Thus, members of Blastocladiomycota are commonly called "blastoclads" by mycologists. Alternatively, members of Blastocladiomycota, Chytridiomycota, and Neocallimastigomycota lumped together as the zoosporic true fungi. Blastocladiomycota contains 5 families and approximately 12 genera. This early diverging branch of kingdom Fungi is the first to exhibit alternation of generations. As well, two (once) popular model organisms—Allomyces macrogynus and Blastocladiella emersonii—belong to this phylum.

<span class="mw-page-title-main">Zoopagomycotina</span> Subdivision of fungi

The Zoopagomycotina are a subdivision of the fungal division Zygomycota sensu lato. It contains 5 families and 20 genera. Relationships among and within subphyla of Zygomycota are poorly understood, and their monophyly remains in question, so they are sometimes referred to by the informal name zygomycetes.

The Harpellales are an order of fungi classified in the subdivision Kickxellomycotina. Thalli are either unbranched or branched, producing basipetal series of trichospores. Zygospores are biconical. Species in the order are found attached to the gut lining of aquatic larvae of Insecta or (rarely) Isopoda. Harpellales are divided into two families, the Harpellaceae and the Legeriomycetaceae. According to the Dictionary of the Fungi, the order contains 38 genera and 200 species. The order was formally described in 1978 Mycotaxon publication. Harpellales has served as a model to study and understand the evolution, growth, and biodiversity of other such fungi found in the gut as species are plentiful around the world.

<i>Corallochytrium</i> Genus of unicellular organisms

Corallochytrium belongs to the class of Corallochytrea within Teretosporea and is a sister group to Ichthyosporea. Corallochytrium limacisporum is the only species of Corallochytrium known so far. It was first discovered and named in the Arabian Sea’s coral lagoons by Kaghu-Kumar in 1987. It was first thought to be a member of the fungi-like thraustochytrids, however, this was later disproven due to Corallochytriums lack of cilia and sagenogenetosome. Little research has been done on the life cycle or morphology. Most research concerning this genus has been done to uncover the evolution of animals and fungi, as Corallochytrium possess both animal and fungal enzymatic trademarks.

<span class="mw-page-title-main">Ichthyophonida</span> Order of parasitic animals

Ichthyophonida is an order of parasitic eukaryotes.

<span class="mw-page-title-main">Holozoa</span> Clade containing animals and some protists

Holozoa is a clade of organisms that includes animals and their closest single-celled relatives, but excludes fungi and all other organisms. Together they amount to more than 1.5 million species of purely heterotrophic organisms, including around 300 unicellular species. It consists of various subgroups, namely Metazoa and the protists Choanoflagellata, Filasterea, Pluriformea and Ichthyosporea. Along with fungi and some other groups, Holozoa is part of the Opisthokonta, a supergroup of eukaryotes. Choanofila was previously used as the name for a group similar in composition to Holozoa, but its usage is discouraged now because it excludes animals and is therefore paraphyletic.

<span class="mw-page-title-main">Amoebidiidae</span> Family of protozoa

Amoebidiidae is a family of single-celled eukaryotes, previously thought to be zygomycete fungi belonging to the class Trichomycetes, but molecular phylogenetic analyses place the family with the opisthokont group Mesomycetozoea. The family was originally called Amoebidiaceae, and considered the sole family of the fungal order Amoebidiales that included two genera: Amoebidium and Paramoebidium. However, Amoebidiidae is now monogeneric as it was recently emended to include only Amoebidium. Species of Amoebidium are considered obligate symbionts of freshwater-dwelling arthropod hosts such as midge larvae and water fleas (Daphnia). However, because Amoebidium species attach to the exoskeleton (exterior) of the host and grow in axenic culture, at least some species may be facultative symbionts.

Smittium is a genus of fungi in the order Harpellales. It is the largest genus in the order. As of 2013, there were 81 described species. Many of these have been formally described only recently; in 1998 there were just 46. Several have been transferred to Smittium from other genera, such as Orphella, Rubetella, Genistella, and Typhella. In general, the genus has a cosmopolitan distribution, but some species are limited to small regions.

Howard C. Whisler (1931–2007) was an American mycologist. Born in Oakland, California, he attended Berkeley schools and then Palo Alto High School. Howard worked on his undergraduate degree at Oregon State College for two years and then went to the University of California, Berkeley, where he completed a Bachelor of Science degree in plant pathology in 1954. He joined the United States Air Force from 1954 to 1956 stationed in Italy. He returned to University of California, Berkeley after his military life and had finished his doctoral degree with Ralph Emerson in 1960. From 1960 to 1961 he held a post doctoral NATO-NSF Fellowship in France, at the Université de Montpellier. Howard was appointed assistant professor of Botany at McGill University in 1961. He was appointed to the faculty at the University of Washington on March 15, 1963 and worked until he died on September 16, 2007, at the age of 76.

<span class="mw-page-title-main">Trichomycetes</span> Group of fungi

Trichomycetes refers to a group of fungi in the division Zygomycota that grow in the guts of arthropods living in aquatic habitats. The name is obsolete, having not been validly published. Species formerly placed in the Trichomycetes are now placed in the orders Harpellales and Asellariales, both in the suborder subdivision Kickxellomycotina, while Amoebidiales and Eccrinales are included in Opisthokonta.

Robert W. Lichtwardt was a Brazilian-born American mycologist specializing in the study of arthropod-associated, gut-dwelling fungi (trichomycetes). He is known for his online monograph and interactive keys to trichomycete taxa.

<i>Paramoebidium</i> Genus of eukaryotes

Paramoebidium is a genus of unicellular, symbiotic eukaryotes that inhabit the digestive tract of immature freshwater arthropod hosts. Paramoebidium is classified in the opisthokont class Mesomycetozoea, and is the sole genus in the family Paramoebidiidae. Prior to 2005, Paramoebidium species were tentatively placed with the fungal group Trichomycetes due to their habitation of arthropod guts, host overlap between various Paramoebidium and fungal trichomycete taxa, and similar vegetative growth form.

<span class="mw-page-title-main">Paramoebidiidae</span> Family of eukaryotes

Paramoebidiidae is a family of single-celled eukaryotes, previously thought to be zygomycete fungi belonging to the class Trichomycetes, but molecular phylogenetic analyses place the family with the opisthokont group Mesomycetozoea. The family was originally called Amoebidiaceae, and considered the sole family of the fungal order Amoebidiales that included two genera, Amoebidium and Paramoebidium. However, Paramoebidium is now the sole genus of the family Paramoebidiidae and Amoebidiidae is likewise monogeneric as it was recently emended to include only Amoebidium. Species of Paramoebidium are obligate symbionts of immature freshwater-dwelling arthropod hosts such as mayfly and stonefly nymphs and black fly larvae. Paramoebidium species attach to the digestive tract lining of their host via a secreted holdfast.

<i>Abeoforma whisleri</i> Single-celled organism

Abeoforma whisleri is a single-celled eukaryote that belongs to the Ichthyosporea clade, a group of protists closely related to animals.

<i>Pirum gemmata</i>

Pirum gemmata is a unicellular eukaryote that belongs to the Ichthyosporea clade, a group of protists closely related to animals. P. gemmata was isolated from the gut contents of a marine invertebrate, specifically the detritivorous peanut worm Phascolosoma agassizii.

References

  1. 1 2 3 4 Cienkowski, L. 1861. Ueber parasitische Schläuche auf Crustaceen und einigen Insektenlarven (Amoebidium parasiticum m.). Botanische Zeitung19: 169-174.
  2. ↑ "Amoebidium". NCBI taxonomy. Bethesda, MD: National Center for Biotechnology Information. Retrieved 17 August 2018. Amoebidium appalachense Amoebidium parasiticum
  3. ↑ "Amoebidium". www.mycobank.org. Retrieved 2020-05-17.
  4. ↑ "Amoebidium". www.speciesfungorum.org. Retrieved 2020-05-17.
  5. ↑ Mendoza L, Taylor JW, Ajello L (October 2002). "The class mesomycetozoea: a heterogeneous group of microorganisms at the animal-fungal boundary". Annu. Rev. Microbiol. 56: 315–44. doi : 10.1146/annurev.micro.56.012302.160950
  6. ↑ Will Karlisle Reeves (2003). "Emendation of the family name Amoebidiaceae (Choanozoa, Mesomycetozoa, Ichthyosporea)". Comparative Parasitology. 70 (1): 78–79. doi : 10.1654/1525-2647
  7. 1 2 Reynolds, N.K., M.E. Smith, E.D. Tretter, J. Gause, D. Heeney, M.J. Cafaro, J.F. Smith, S.J. Novak, W.A. Bourland, M.M. White. 2017. Resolving relationships at the animal-fungal divergence: A molecular phylogenetic study of the protist trichomycetes (Ichthyosporea, Eccrinida). Molecular Phylogenetics and Evolution 109, 447-464.
  8. 1 2 3 4 5 6 7 Lichtwardt, R.W., M.J. Cafaro, M.M. White. 2001. The Trichomycetes: Fungal Associates of Arthropods Revised Edition. Published online http://www.nhm.ku.edu/%7Efungi/Monograph/Text/Mono.htm Archived 2017-04-26 at the Wayback Machine
  9. 1 2 Whisler, H.C., 1960. Pure culture of the Trichomycete, Amoebidium parasiticum. Nature 186, 732-733.
  10. ↑ Lichtenstein, J. L. 1917a. Sur un Amoebidium a commensalisme interne du rectum des larves d' Anaximperator Leach: Amoebidiumfasciculatum n. sp. Archives de Zoologie Expérimentale et Générale56: 49-62.
  11. ↑ Manier, J.-F., and Raibaut, A. 1969. Cycle biologique du Trichomycète Amoebidiumparasiticum (Cienkowski). 16-mm film. Service du film de recherche scientifique, Paris.
  12. ↑ White, M.M., Siri, A., and Lichtwardt, R.W. 2006. Trichomycete insect symbionts in Great Smoky Mountains National Park and vicinity. Mycologia 98: 333-352.
  13. ↑ Lichtwardt, R. W., and Williams, M. C. 1992. Two new Australasian species of Amoebidiales associated with aquatic insect larvae, and comments on their biogeography. Mycologia84: 376-383.
  14. ↑ Lichtwardt, R. W. 1997. Costa Rican gut fungi (Trichomycetes) infecting lotic insect larvae. Revista de Biología Tropical 45: 1339-1383.
  15. 1 2 Chatton, E. 1906. Sur la morphologie et l'évolution de l' Amoebidium recticola, nouvelle espèce commensale des Daphnies. Archives de Zoologie Expérimentale et Générale4, 5: 33-38.
  16. ↑ Lichtwardt, R.W. 2001. Trichomycetes: fungi in relationship with insects and other arthropods. In: Symbiosis. J. Seckbach, ed. Kluwer Academic Publishers, Netherlands, p. 515-588.
  17. ↑ Chatton, E. 1920. Les membranes péritrophiques des Drosophiles (Diptères) et des Daphnies (Cladocères); leur genèse et leur role à l'égard des parasites intestinaux. Bulletin de la Société Zoologique deFrance45: 265-280.
  18. ↑ Whisler, H. C. 1962. Culture and nutrition of Amoebidium parasiticum. American Journal of Botany49: 193-199.
  19. 1 2 Trotter, M. J., and Whisler, H. C. 1965. Chemical composition of the cell wall of Amoebidium parasiticum. Canadian Journal of Botany43: 869-876.
  20. 1 2 Whisler, H. C. 1966. Host-integrated development in the Amoebidiales. The Journal of Protozoology13: 183-188.
  21. ↑ Lichtwardt, R. W. 1986. The Trichomycetes: Fungal Associates of Arthropods. Springer-Verlag, New York. 343 pp.
  22. ↑ Whisler, H. C. 1968. Developmental control of Amoebidium parasiticum. Developmental Biology17: 562-570.
  23. ↑ Benny, G. L., and O'Donnell, K. 2000. Amoebidium parasiticum is a protozoan, not a Trichomycete. Mycologia92: 1133-1137.
  24. ↑ Ustinova, I, Krienitz, L., and Huss, V. A. R. 2000. Hyaloraphidium curvatum is not a green alga, but a lower fungus; Amoebidium parasiticum is not a fungus, but a member of the DRIPS. Protist151: 253-262.
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