The Labyrinthulomycetes ( ICBN) or Labyrinthulea (

ICZN The International Code of Zoological Nomenclature (ICZN) is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals. It is also informally known as the ICZN Code, for its publisher, the I ...

) are a class of protists that produce a network of filaments or tubes, which serve as tracks for the cells to glide along and absorb nutrients for them. The two main groups are the labyrinthulids (or slime nets) and thraustochytrids. They are mostly

marine Marine is an adjective meaning of or pertaining to the sea or ocean. Marine or marines may refer to: Ocean * Maritime (disambiguation) * Marine art * Marine biology * Marine debris * Marine habitats * Marine life * Marine pollution Military * ...

, commonly found as parasites on algae and seagrasses or as decomposers on dead plant material. They also include some parasites of marine invertebrates.

Characteristics

Although they are outside the cells, the filaments of Labyrinthulomycetes are surrounded by a membrane. They are formed and connected with the cytoplasm by a unique organelle called a sagenogen or bothrosome. The cells are uninucleated and typically ovoid, and move back and forth along the

amorphous In condensed matter physics and materials science, an amorphous solid (or non-crystalline solid, glassy solid) is a solid that lacks the long-range order that is characteristic of a crystal. Etymology The term comes from the Greek ''a'' ("wi ...

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.

Classification

Labyrinthulomycetes/Labyrinthulea used to belong to the defunct fungal phylum Labyrinthulomycota. They were originally considered unusual slime moulds, although they are not very similar to the other sorts. The structure of their zoospores and genetic studies show them to be a primitive group of heterokonts, but their classification and treatment remains somewhat unsettled. This class has usually two orders, Labyrinthulales and Thraustochytriales (ICBN), or Labyrinthulida and Thraustochytrida (ICZN), but a third has recently been proposed. * Genus '' Stellarchytrium'' FioRito & Leander 2016 * Family Oblongichytriidae Cavalier-Smith 2012 ** Genus '' Oblongichytrium'' Yokoyama & Honda 2007 * Order Labyrinthulida Doflein 1901 ** Family Aplanochytriidae Leander ex Cavalier-Smith 2012 *** Genus ''

Aplanochytrium The genus ''Aplanochytrium'' is part of the class Labyrinthulomycetes. It is a sister genus of ''Labyrinthula'' and thraustochytrids. The major characteristic of all three genera is the production of an extension of the plasma membrane and the ec ...

'' Bahnweg & Sparrow 1972 'Labyrinthuloides'' Perkins 1973">Labyrinthuloides.html" ;"title="'Labyrinthuloides">'Labyrinthuloides'' Perkins 1973 ** Family Labyrinthulidae Cienkowski 1867 *** Genus ''Labyrinthomyxa'' Duboscq 1921 *** Genus ''Pseudoplasmodium'' Molisch 1925 *** Genus ''

Labyrinthula The genus ''Labyrinthula'' is part of the protist group Labyrinthulomycetes and contains thirteen species. The major feature of this genus is the formation of an ectoplasmic net secreted by specialized organelles called bothrosomes which surro ...

'' Cienkowski 1864 'Labyrinthodictyon'' Valkanov 1969; ''Labyrinthorhiza">Labyrinthodictyon.html" ;"title="'Labyrinthodictyon">'Labyrinthodictyon'' Valkanov 1969; ''Labyrinthorhiza'' Chadefaud 1956] * Order Amphitremida Gomaa et al. 2013 ** Family Diplophryidae Cavalier-Smith 2012 *** Genus ''Diplophrys'' Barker 1868 ** Family Amphitrematidae Poche 1913 *** Genus '' Paramphitrema'' Valkanov 1970 *** Genus '' Archerella'' Loeblich & Tappan 1961 *** Genus ''

Amphitrema ''Amphitrema'' is a genus of testate amoeba in the family Amphitremidae. The genus is commonly found in ''Sphagnum''-dominated peatlands. All species of this genus are mixotrophic and harbor unicellular algae belonging to genus ''Chlorella ...

'' Archer 1867 * Order Thraustochytriida Alderman & 1974 ** Genus '' Pyrrhosorus'' Juel 1901 ** Genus '' Thanatostrea'' Franc & Arvy 1969 ** Family Althorniidae Cavalier-Smith 2012 *** Genus '' Althornia'' Jones & Alderman 1972 ** Family Sorodiplophryidae Cavalier-Smith 2012 *** Genus '' Sorodiplophrys'' Olive & Dykstra 1975 ** Family Amphifilidae Cavalier-Smith 2012 *** Genus '' Amphifila'' Cavalier-Smith 2012 *** Genus '' Fibrophrys columna'' Takahashi et al. 2016 ** Family Thraustochytriidae Sparrow ex Cejp 1959 *** Genus '' Japonochytrium'' Kobayasi & Ôkubo 1953 *** Genus '' Monorhizochytrium'' Doi & Honda 2017 *** Genus '' Sicyoidochytrium'' Yokoy., Salleh & Honda 2007 *** Genus '' Aurantiochytrium'' Yokoy. & Honda 2007 *** Genus '' Ulkenia'' Gaertn. 1977 *** Genus '' Parietichytrium'' Yokoy., Salleh & Honda 2007 *** Genus '' Botryochytrium'' Yokoy., Salleh & Honda 2007 *** Genus '' Schizochytrium'' Goldst. & Belsky emend. Booth & Mill. *** Genus '' Thraustochytrium'' Sparrow 1936 *** Genus '' Hondaea'' Amato & Cagnac 2018 *** Genus '' Labyrinthulochytrium Hassett & Gradinger 2018''

Genetic code

The labyrinthulomycete '' Thraustochytrium aureum'' is notable for the alternative genetic code of its

mitochondria A mitochondrion (; ) is an organelle found in the Cell (biology), cells of most Eukaryotes, such as animals, plants and Fungus, fungi. Mitochondria have a double lipid bilayer, membrane structure and use aerobic respiration to generate adenosi ...

which use as a stop codon instead of coding for Leucine. This code is represented by NCBI translation table 23, ''Thraustochytrium'' mitochondrial code.

Gallery

File:Aplanolm.jpg, ''

'' sp. under

light microscope The optical microscope, also referred to as a light microscope, is a type of microscope that commonly uses visible light and a system of lenses to generate magnified images of small objects. Optical microscopes are the oldest design of microsco ...

File:Aplanosem.png, ''Aplanochytrium'' sp. under SEM File:Aurantiochytrium limacinum SR21.jpg, ''Aurantiochytrium'' sp. File:Collection Penard MHNG Specimen 48-2-4 Amphitrema stenostoma.tif, Test of ''

'', a testate amoeba recently included in the group File:Tsenkovsky Lev Semyonovich.jpg,

Leon Cienkowski Tsenkovsky Lev Semyonovich

Lev Semyonovich Tsenkovsky (Leon ...

, Polish botanist who in 1867 described ''

'', the first genus of the groupCienkowski, L. (1867). Ueber den Bau und die Entwicklung der Labyrinthuleen. ''Arch. mikr. Anat.'', 3:274

References

External links

Labyrinthulomycota
{{Taxonbar, from1=Q1148791, from2=Q16653009 Heterokont classes Bigyra