| Ellobiopsis | |
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| Genus: | Ellobiopsis Caullery, 1910 |
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Ellobiopsis caridarum | |
Ellobiopsis is agenus ofunicellular,ectoparasiticeukaryotes causing disease in crustaceans.[1] This genus is widespread and has been found infectingcopepods from both marine and freshwater ecosystems.[2] parasitism has been seen to interfere with fertility in both sexes of copepods.[3][2]
TheEllobiopsistype species,Ellobiopsis chattoni, was first described in 1910 by Caullery after being isolated from an infectedcopepod found in theMediterranean Sea.Ellobiopsis was first classified as adinoflagellate, but observation of aspore formingorganelle concluded that theEllobiopsis was not a part of this group.Phylogeny based on smallsubunit (SSU) ribosomal DNA placesEllobiopsis in theAlveolata.[4] In the family Ellobiopsidae, the most closely related genus isThalassomyces.[4] Threespecies have been defined in this genus:Ellobiopsis chattoni Caullery (1910),Ellobiopsis elongata Steuer (1932)and Ellobiopsis fagei Hovasse (1951). These species are characterized by morphology of their reproductive structures and their ability to infect species specific hosts.
During dispersal, unflagellated spores ofEllobiopsis land on the surface of potential hosts. Once in contact with a host, the cell body of the organism grows and takes on an oval shape. A rhizoid pierces the hostcuticle to root the parasite in the copepod tissue. The cell body constricts in the center and differentiate into trophomere and gonomere, proximal and distal to the host body. The cell forms a conical shape. The number of gonomeres is distinguishes species.[2] The cell body has been seen to grows to a length of 700 μm and a width of 350 μm.[5]
Theparasitic life cycle ofEllobiopsis chattoni begins with a spore that lands on the surface of a host appendage. A stalk attaches the parasite to the host and it uses an organelle for penetration, called a rhizoid, of the cuticle and to root itself in the host tissue.[2][5] As the cell grows the root is used for absorption, causing damaging to the local host tissue.[2] Once established at a specific size, approximately 400 μm,[5] the cell body begins to partition itself in half. The half not attached to the host becomes the gonomere and the half attached to the host is named the trophomere. As the gonomere and trophomere partitioning continues to partition, the spore begins to form in the gonomere and it takes on a granulated texture. The pre-spores are released from the reproductive body and form spores for dispersal to the next host.[4]