SEM image of thraustochytrid showing ectoplasmic net.
Scientific classification
Domain:
Eukaryota
Clade:
Diaphoretickes
Clade:
SAR
Clade:
Stramenopiles
Phylum:
Bigyra
Class:
Labyrinthulea
Order:
Thraustochytrida Sparrow, 1973
Families
Althorniidae
Amphifilidae
Amphitremidae
Diplophryidae
Oblongichytriidae
Sorodiplophryidae
Thraustochytriidae
Synonyms
Labyrinthulales
Thraustochytrids are single-celled saprotrophic eukaryotes (decomposers) that are widely distributed in marine ecosystems, and which secrete enzymes including, but not limited to amylases, proteases, phosphatases.[1][2][3][4][5][6] They are most abundant in regions with high amounts of detritus and decaying plant material.[1] They play an important ecological role in mangroves, where they aid in nutrient cycling by decomposing decaying matter.[7][8][9][10] Additionally, they contribute significantly to the synthesis of omega-3 polyunsaturated fatty acids (PUFAs): docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA), which are essential fatty acids for the growth and reproduction of crustaceans.[11][12][13] Thraustochytrids are members of the class Labyrinthulea, a group of protists that had previously been incorrectly categorized as fungi due to their similar appearance and lifestyle.[14] With the advent of DNA sequencing technology, labyrinthulomycetes were appropriately placed with other stramenopiles and subsequently categorized as a group of Labyrinthulomycetes.
There are several characteristics which are unique to Thraustochytrids, including their cell wall made of extracellular non-cellulosic scales, zoospores with characteristic heterokont flagella, and a bothrosome-produced ectoplasmic net, which is used for extracellular digestion.[15][16][17][18][19][20][21][22][23] Thraustochytrids are morphologically variable throughout their life cycle. They have a main vegetative asexual cycle, which can vary depending on the genus.[24][10] While sexual reproduction has been observed in this group, it remains poorly understood.[25]
Thraustochytrids are of particular biotechnical interest due to their high concentrations of docosahexaenoic acid (DHA), palmitic acid, carotenoids, and sterols, all of which have beneficial effects to human health.[10][17][26][27][28][29][30][31][32] Thraustochytrids rely on a plethora of resources such as various sources of organic carbon (vitamins and sugars), and inorganic salts throughout their life cycle.[33][34][35][36][37][38][39][40][41] Scientists have devised several potential uses for thraustochytrids stemming around increasing DHA, fatty acids, and squalene concentrations in vivo by either changing the genetic makeup or medium composition/conditioning.[42][43][44][45][46][47][48] There have also been some breakthroughs which have resulted in gene transfers to plant species in order to make isolation of certain oils easier and cost effective.[49][50] Thraustochytrids are currently cultured for use in fish feed and production of dietary supplements for humans and animals.[51][52][53] In addition, scientists are currently researching new methodologies to convert waste water into useful products like squalene, which can then be utilized for the production of biofuel.[54][55][56][57][58]
^ abRaghukumar, Seshagiri (2002-01-01). "Ecology of the marine protists, the Labyrinthulomycetes (Thraustochytrids and Labyrinthulids)". European Journal of Protistology. 38 (2): 127–145. doi:10.1078/0932-4739-00832. ISSN 0932-4739.
^Raghukumar, S.; Anil, A. C.; Khandeparker, L.; Patil, J. S. (2000-05-19). "Thraustochytrid protists as a component of marine microbial films". Marine Biology. 136 (4): 603–609. Bibcode:2000MarBi.136..603R. doi:10.1007/s002270050720. ISSN 0025-3162. S2CID 86089872.
^Raghukumar, S.; Sharma, Sumita; Raghukumar, Chandralata; Sathe-Pathak, Veena; Chandramohan, D. (1994-10-27). "Thraustochytrid and fungal component of marine detritus. IV. Laboratory studies on decomposition of leaves of the mangrove Rhizophora apiculata Blume". Journal of Experimental Marine Biology and Ecology. 183 (1): 113–131. doi:10.1016/0022-0981(94)90160-0. ISSN 0022-0981.
^Nagano, Naoki; Matsui, Shou; Kuramura, Tomoyo; Taoka, Yousuke; Honda, Daiske; Hayashi, Masahiro (2010-05-05). "The Distribution of Extracellular Cellulase Activity in Marine Eukaryotes, Thraustochytrids". Marine Biotechnology. 13 (2): 133–136. doi:10.1007/s10126-010-9297-8. ISSN 1436-2228. PMID 20443042. S2CID 12148424.
^Liu, Ying; Singh, Purnima; Sun, Yuan; Luan, Shengji; Wang, Guangyi (2013-11-24). "Culturable diversity and biochemical features of thraustochytrids from coastal waters of Southern China". Applied Microbiology and Biotechnology. 98 (7): 3241–3255. doi:10.1007/s00253-013-5391-y. ISSN 0175-7598. PMID 24270895. S2CID 15905195.
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^Margulis, Lynn (1990). Handbook of protoctista : the structure, cultivation, habitats, and life histories of the eukaryotic microorganisms and their descendants exclusive of animals, plants, and fungi. Jones and Bartlett. ISBN 0-86720-052-9. OCLC 802792335.
^Fan, King Wai; Chen, Feng (2007), "Production of High-Value Products by Marine Microalgae Thraustochytrids", Bioprocessing for Value-Added Products from Renewable Resources, Elsevier, pp. 293–323, doi:10.1016/b978-044452114-9/50012-8, ISBN 9780444521149, retrieved 2022-03-29
^ abcCite error: The named reference Morabito-2019 was invoked but never defined (see the help page).
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^Lowenstam, Heinz A.; Weiner, Stephen (1989-07-27), "Protoctista", On Biomineralization, Oxford University Press, doi:10.1093/oso/9780195049770.003.0006, ISBN 978-0-19-504977-0, retrieved 2022-03-27
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^ abPerkins, E.J. (1974), "The Marine Environment", Biology of Plant Litter Decomposition, Elsevier, pp. 683–721, doi:10.1016/b978-0-12-215002-9.50020-4, ISBN 9780122150029, retrieved 2022-03-27
^MOSS, STEPHEN T. (1985). "An ultrastructural study of taxonomically significant characters of the Thraustochytriales and the Labyrinthulales". Botanical Journal of the Linnean Society. 91 (1–2): 329–357. doi:10.1111/j.1095-8339.1985.tb01154.x. ISSN 0024-4074.
^Perkins, Frank O. (1972). "The ultrastructure of holdfasts, ?rhizoids?, and ?slime tracks? in thraustochytriaceous fungi and Labyrinthula spp". Archiv für Mikrobiologie. 84 (2): 95–118. doi:10.1007/bf00412431. ISSN 0302-8933. PMID 4559400. S2CID 35154048.
^Perkins, Frank O. (1973-02-01). "Observations of thraustochytriaceous (Phycomycetes) and labyrinthulid (Rhizopodea) ectoplasmic nets on natural and artificial substrates—an electron microscope study". Canadian Journal of Botany. 51 (2): 485–491. doi:10.1139/b73-057. ISSN 0008-4026.
^Porter, David (1972). "Cell division in the marine slime mold,Labyrinthula sp., and the role of the bothrosome in extracellular membrane production". Protoplasma. 74 (4): 427–448. doi:10.1007/bf01281960. ISSN 0033-183X. S2CID 41333647.
^Bennett, Reuel M.; Honda, D.; Beakes, Gordon W.; Thines, Marco (2017), "Labyrinthulomycota", Handbook of the Protists, Cham: Springer International Publishing, pp. 507–542, doi:10.1007/978-3-319-28149-0_25, ISBN 978-3-319-28147-6, retrieved 2022-03-27
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^Honda, Daiske; Yokochi, Toshihiro; Nakahara, Toro; Erata, Mayumi; Higashihara, Takanori (1998-04-01). "Schizochytrium limacinum sp. nov., a new thraustochytrid from a mangrove area in the west Pacific Ocean". Mycological Research. 102 (4): 439–448. doi:10.1017/S0953756297005170. ISSN 0953-7562.
^Ganuza, Eneko; Yang, Shanshan; Amezquita, Magdalena; Giraldo-Silva, Ana; Andersen, Robert A. (2019-04-01). "Genomics, Biology and Phylogeny Aurantiochytrium acetophilum sp. nov. (Thraustrochytriaceae), Including First Evidence of Sexual Reproduction". Protist. 170 (2): 209–232. doi:10.1016/j.protis.2019.02.004. ISSN 1434-4610. PMID 31100647. S2CID 109224340.
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basal membrane to merge. In thraustochytrids, the cell wall is rich in galactose and xylose. Characteristic of thraustochytrids is their ectoplasmic net—which...
them. The two main groups are the labyrinthulids (or slime nets) and thraustochytrids. They are mostly marine, commonly found as parasites on algae and seagrasses...
stramenopile organisms. Thraustochytrids are common protists in marine sediments and the water column, but only a few thraustochytrids are known as parasites...
defining characteristics of thraustochytrids. After phylogenetic analysis, Corallochytrium was determined not to be a thraustochytrid, but rather related to...
Schizochytrium limacinum is a species of thraustochytrids first isolated from a mangrove area in the western Pacific Ocean. It differs from other Schizochytrium...
as a type of leptocephali, feed on marine snow. Organisms, such as thraustochytrids and hydrozoan tissue, were consumed by these larva in a grouped manner...
First included in the order thraustochytrids, Aplanochytrium is now considered a sister group of the thraustochytrids and Labyrinthula. The previous...
being Althorniidae with only one genus, Althornia. As all remaining thraustochytrids belong to Thraustochytriidae, it is the most taxonomically diverse...
Takanori (April 1998). "Schizochytrium limacinum sp. nov., a new thraustochytrid from a mangrove area in the west Pacific Ocean". Mycological Research...
increasing minority of parasitic thraustochytrids. Hasset, Brandon T. (April 2020). "A Widely Distributed Thraustochytrid Parasite of Diatoms Isolated from...
(2002). "Ecology of the marine protists, the Labyrinthulomycetes (Thraustochytrids and Labyrinthulids)". European Journal of Protistology. 38 (2): 127–145...
Role of Silicate in the Parasitism of Pleurosigma sp. Diatoms by the Thraustochytrid Phycophthorum isakeiti (Master thesis). The Arctic University of Norway...
although other parasites of G. delicatula are also likely involved. Thraustochytrids are considered to be important decomposers in ecosystems. Aurantiochytrium...
Panayiotis V. (17 September 2013). "Development of Genomic Resources for a thraustochytrid Pathogen and Investigation of Temperature Influences on Gene Expression"...