Thraustochytriidae | |
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SEM image of a Phycophthorum zoospore | |
Scientific classification ![]() | |
Domain: | Eukaryota |
Clade: | Diaphoretickes |
Clade: | Sar |
Clade: | Stramenopiles |
Phylum: | Bigyra |
Class: | Labyrinthulea |
Order: | Thraustochytrida |
Family: | Thraustochytriidae Sparrow ex Cejp 1959 [1] |
Type genus | |
Thraustochytrium Sparrow, 1936 emend. T.W. Johnson, 1961 | |
Genera [2] [3] | |
Synonyms [1] | |
Thraustochytriaceae |
Thraustochytriidae or Thraustochytriaceae is a family of heterotrophic protists. They are unicellular eukaryotes characterized by round cells that use a cytoplasmic network to feed and anchor to the substrate, with an appearance similar to chytrids.
Members of the Thraustochytriidae form ovoid or spherical thalli (or cells) associated with a fine ectoplasmic (i.e. outer cytoplasm) network of rhizoid-like threads that act as their anchoring and feeding structures. In general size and appearance, these thalli are superficially similar to those of hyphochytrids and chytrid fungi. [1]
Thraustochytriidae are mostly saprotrophic. Their usual substrates are decaying plants and macrophyte algae. The most common representatives from Thraustochytriidae are Aurantiochytrium , Schizochytrium , Thraustochytrium and Ulkenia , found on decaying plant remains, in sediments and in sea water. Most species have a very wide or cosmopolitan distribution. They are abundant in estuarines of coastal areas, where their usual substrate arrives from terrestrial ecosystems in the form of detritus. [4]
There are, however, some parasitic organisms present in the family. For example, Phycophthorum parasitizes pennate diatoms. [3] The QPX, of unknown genus or species, is a parasite of the hard clam. [5]
Thraustochytriidae/Thraustochytriaceae belongs to the Labyrinthulea, a group of heterotrophic stramenopiles that generate cytoplasmic networks outside their cells. [1] In particular, it is one of the two families of the labyrinthulean order Thraustochytrida, the other one being Althorniidae with only one genus, Althornia . As all remaining thraustochytrids belong to Thraustochytriidae, it is the most taxonomically diverse family of the order. [3]