Apicomplexa

Apicomplexa
Scientific classification
Domain:	Eukaryota
Clade:	Diaphoretickes
Clade:	TSAR
Clade:	SAR
Clade:	Alveolata
Phylum:	Apicomplexa; Levine, 1970
Classes & Subclasses Perkins, 2000
	Aconoidasida (= Hematozoa); Conoidasida Coccidia; (= Coccidiasina); Gregarinia; (= Gregarinasina); ;

The Apicomplexa (also called Apicomplexia; single: apicomplexan) are organisms of a large phylum of mainly parasitic alveolates. Most possess a unique form of organelle structure that comprises a type of non-photosynthetic plastid called an apicoplast—with an apical complex membrane. The organelle's apical shape (e.g., see Ceratium furca) is an adaptation that the apicomplexan applies in penetrating a host cell.

The Apicomplexa are unicellular and spore-forming. Most are obligate endoparasites of animals,^[3] except Nephromyces, a symbiont in marine animals, originally classified as a chytrid fungus,^[4] and the Chromerida, some of which are photosynthetic partners of corals. Motile structures such as flagella or pseudopods are present only in certain gamete stages.

The Apicomplexa are a diverse group that includes organisms such as the coccidia, gregarines, piroplasms, haemogregarines, and plasmodia. Diseases caused by Apicomplexa include:

Babesiosis (Babesia)
Malaria (Plasmodium)
Cryptosporidiosis (Cryptosporidium parvum)
Cyclosporiasis (Cyclospora cayetanensis)
Cystoisosporiasis (Cystoisospora belli)
Toxoplasmosis (Toxoplasma gondii)

The name Apicomplexa derives from two Latin words—apex (top) and complexus (infolds)—for the set of organelles in the sporozoite. The Apicomplexa comprise the bulk of what used to be called the Sporozoa, a group of parasitic protozoans, in general without flagella, cilia, or pseudopods. Most of the Apicomplexa are motile, however, with a gliding mechanism^[5] that uses adhesions and small static myosin motors.^[6] The other main lines of this obsolete grouping were the Ascetosporea (a group of Rhizaria), the Myxozoa (highly derived cnidarian animals), and the Microsporidia (derived from fungi). Sometimes, the name Sporozoa is taken as a synonym for the Apicomplexa, or occasionally as a subset.

^ Levine ND (1970). "Taxonomy of the Sporozoa". J Parasitol. 56 (4, Sect. 2, Part 1: Supplement: Proceedings Of the Second International Congress of Parasitology): 208–9. JSTOR 3277701.
^ Levine ND (May 1971). "Uniform Terminology for the Protozoan Subphylum Apicomplexa". J Eukaryot Microbiol. 18 (2): 352–5. doi:10.1111/j.1550-7408.1971.tb03330.x.
^ Jadwiga Grabda (1991). Marine fish parasitology: an outline. VCH. p. 8. ISBN 978-0-89573-823-3.
^ Saffo M. B.; McCoy A. M.; Rieken C.; Slamovits C. H. (2010). "Nephromyces, a beneficial apicomplexan symbiont in marine animals". Proceedings of the National Academy of Sciences. 107 (37): 16190–5. Bibcode:2010PNAS..10716190S. doi:10.1073/pnas.1002335107. PMC 2941302. PMID 20736348.
^ Kappe, Stefan H.I.; et al. (January 2004). "Apicomplexan gliding motility and host cell invasion: overhauling the motor model". Trends in Parasitology. 20 (1): 13–16. CiteSeerX 10.1.1.458.5746. doi:10.1016/j.pt.2003.10.011. PMID 14700584.
^ Sibley, L.D.I. (Oct 2010). "How apicomplexan parasites move in and out of cells". Curr Opin Biotechnol. 21 (5): 592–598. doi:10.1016/j.copbio.2010.05.009. PMC 2947570. PMID 20580218.

[Levine1970-1] Levine ND (1970). "Taxonomy of the Sporozoa". J Parasitol. 56 (4, Sect. 2, Part 1: Supplement: Proceedings Of the Second International Congress of Parasitology): 208–9. JSTOR 3277701.

[2] Levine ND (May 1971). "Uniform Terminology for the Protozoan Subphylum Apicomplexa". J Eukaryot Microbiol. 18 (2): 352–5. doi:10.1111/j.1550-7408.1971.tb03330.x.

[3] Jadwiga Grabda (1991). Marine fish parasitology: an outline. VCH. p. 8. ISBN 978-0-89573-823-3.

[4] Saffo M. B.; McCoy A. M.; Rieken C.; Slamovits C. H. (2010). "Nephromyces, a beneficial apicomplexan symbiont in marine animals". Proceedings of the National Academy of Sciences. 107 (37): 16190–5. Bibcode:2010PNAS..10716190S. doi:10.1073/pnas.1002335107. PMC 2941302. PMID 20736348.

[5] Kappe, Stefan H.I.; et al. (January 2004). "Apicomplexan gliding motility and host cell invasion: overhauling the motor model". Trends in Parasitology. 20 (1): 13–16. CiteSeerX 10.1.1.458.5746. doi:10.1016/j.pt.2003.10.011. PMID 14700584.

[6] Sibley, L.D.I. (Oct 2010). "How apicomplexan parasites move in and out of cells". Curr Opin Biotechnol. 21 (5): 592–598. doi:10.1016/j.copbio.2010.05.009. PMC 2947570. PMID 20580218.

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