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''Halofolliculina corallasia'' is a heterotrich ciliate identified as a cause of the syndrome called Skeletal Eroding Band (SEB). It is the first coral disease pathogen that is a protozoan as well as the first known to be an eucaryote; all others identified are bacteria.〔 Like other members of the folliculinid family, ''H. corallasia'' is sessile and lives in a "house" called a lorica, into which the cell can retreat when disturbed. The mouth is flanked by a pair of wing-like projections that are fringed with polykinetids, groups of cilia that work in groups to produce a current that draws food into the "mouth". This species is so far the only known agent causing Skeletal Eroding Band, the most common disease of corals in the Indian and Pacific Oceans, and also found in the Red Sea. A very similar disease was later discovered in the Caribbean Sea, but is caused by a different species of the same genus and occurs in a different type of environment. ==Description== ''Halofolliculina corallasia'' was first observed in reefs near Motupore Island in Papua New Guinea in 1988,〔 and named in 2001. The species name ''corallasia'' is a combination of "coral" and the Greek word ''lasios'' (λάσιος), which means "densely overgrown". ''H. corallasia'' is a member of the ciliate group of protozoans.〔 〕 Ciliates are among the most complex of single-celled eukaryote organisms, distinguished by three characteristics. First, it reproduces both by cell division (splitting one cell into two) and by conjugation, in which two organisms temporarily join in order to swap DNA. Second, it has two cell nuclei. The larger, called the "macronucleus", carries out the normal work of the cell by transcribing DNA into RNA, which is used to control the cell's functions. The smaller "micronucleus" is used only for reproducing the organism by cell division and by conjugation. And third, it has cilia at some stage in its life cycle.〔 Heterotrichs, which are among the largest protozoans, have a spiral of polykinetids around their "mouths". These are groups of cilia that work in groups to produce a current that draws food into the "mouth". Members of the heterotrich family Folliculinidae are sessile, enclosing the rear ends in a lorica (Latin for cuirass, flexible body armor) that is anchored to a surface, and into which the cells retract when disturbed. The mouth is flanked by a pair of wing-like projections that are fringed with polykinetids.〔 ''H. corallasia'' is smaller than other members of the same genus, having a flask-shaped lorica typically 220 µm long and 95 µm wide, and "wings" that are 175 to 200 µm long when fully extended. Its lorica, which is dark gray or black and made of a chitin-like substance, has flaps that close its opening when the cell is retracted.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Halofolliculina corallasia」の詳細全文を読む スポンサード リンク
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