Although they are outside the cells, the filaments of Labyrinthulomycetes are surrounded by amembrane. They are formed and connected with the cytoplasm by a unique organelle called a sagenogen or bothrosome. The cells areuninucleated and typically ovoid, and move back and forth along theamorphous network at speeds varying from 5-150 μm per minute. Among the labyrinthulids, the cells are enclosed within the tubes, and among the thraustochytrids, they are attached to their sides.
Some characteristics of the labyrinthulomycetes can be explained by their origin from ancestral plastids. They produceomega-3 poly-unsaturated fatty acids using adesaturase usually present inchloroplasts. The zoospores oflabyrinthulids have aneyespot composed of membrane-bound granules that resembles eyespots of photosynthetic stramenopiles, which are either within a plastid or believed to be derived from a plastid.[3]
Labyrinthulomycetes or Labyrinthulea used to compose the defunct fungalphylum Labyrinthulomycota.[9] They were originally considered unusualslime moulds, although they are not very similar to the other sorts. The structure of theirzoospores and genetic studies show them to be a primitive group ofheterokonts, but their classification and treatment remains somewhat unsettled.
This class usually contained two orders, Labyrinthulales and Thraustochytriales (ICBN), orLabyrinthulida andThraustochytrida (ICZN), but a different classification has recently been proposed.[6][10][11][1][9]
Family-level clade "Stellarchytriaceae/Stellarchytriidae" – this group is provisionally placed inLabyrinthulida[9][1] but, according to phylogenetic analyses, diverges before the rest of labyrinthulean clades.[11]
^abcAdl 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.PMC6492006.PMID30257078.
^Cavalier-Smith, T. (1997). "Sagenista and bigyra, two phyla of heterotrophic heterokont chromists".Archiv für Protistenkunde.148 (3):253–267.doi:10.1016/S0003-9365(97)80006-1.
^abcTsui, Clement K M; Marshall, Wyth; Yokoyama, Rinka; Honda, Daiske; Lippmeier, J Casey; Craven, Kelly D; Peterson, Paul D; Berbee, Mary L (January 2009). "Labyrinthulomycetes phylogeny and its implications for the evolutionary loss of chloroplasts and gain of ectoplasmic gliding".Molecular Phylogenetics and Evolution.50 (1):129–40.doi:10.1016/j.ympev.2008.09.027.PMID18977305.
^abcBennett, Reuel M.; Honda, D.; Beakes, Gordon W.; Thines, Marco (2017). "Chapter 14. Labyrinthulomycota". In Archibald, John M.; Simpson, Alastair G.B.; Slamovits, Claudio H. (eds.).Handbook of the Protists. Springer. pp. 507–542.doi:10.1007/978-3-319-28149-0_25.ISBN978-3-319-28147-6.
^abFioRito, Rebecca; Leander, Celeste; Leander, Brian (2016). "Characterization of three novel species of Labyrinthulomycota isolated from ochre sea stars (Pisaster ochraceus)".Marine Biology.163 (8): 170.doi:10.1007/s00227-016-2944-5.S2CID43399688.
^Hassett, Brandon T.; Gradinger, Rolf (2018). "New Species of Saprobic Labyrinthulea (=Labyrinthulomycota) and the Erection of a gen. nov. to Resolve Molecular Polyphyly within the Aplanochytrids".Journal of Eukaryotic Microbiology.65 (4):475–483.doi:10.1111/jeu.12494.hdl:10037/13570.ISSN1550-7408.PMID29265676.S2CID46820836.
^Elzanowski A, Ostell J, Leipe D, Soussov V."The Genetic Codes".Taxonomy browser. National Center for Biotechnology Information (NCBI), U.S. National Library of Medicine. Retrieved11 August 2016.
^Cienkowski, L. (1867). Ueber den Bau und die Entwicklung der Labyrinthuleen.Arch. mikr. Anat., 3:274,[1].
![Leon Cienkowski, Russian botanist who in 1867 described Labyrinthula, the first genus of the group[15]](/mt/?noimg=&dark=on&url=https%3a%2f%2fwikipedia.org%2fwiki%2fFile%3aTsenkovsky_Lev_Semyonovich.jpg)
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