- Gregarinasina
Taxobox
color = khaki
name = Gregarines
regnum =Protista
phylum =Apicomplexa
classis =Conoidasida
subclassis = Gregarinasina
subdivision_ranks = Orders
subdivision =Archigregarinorida Eugregarinorida Neogregarinorida The gregarines are a group ofApicomplexa n protozoa, classified as the Gregarinasina or Gregarinea.The gregarines are able to move and change direction along a surface through gliding motility without the use of cilia, flagella, or lamellipodia [Walker et al., 1979] . This is accomplished through the use of an actin and myosin complex [Heintzelman, 2004] . The complexes require an actin cytoskeleton to perform their gliding motions [Mitchison and Cramer, 1996] . In the proposed ‘capping’ model, an uncharacterized protein complex moves rearward, moving the parasites forward [Sibley et al., 1998] .
The large (roughly half a millimeter) parasites inhabit the intestines of a large number of invertebrates. They are not found in humans. However, Gregarinasina is closely related to both
Toxoplasma andPlasmodium , which causetoxoplasmosis andmalaria , respectively. Both protists use protein complexes similar to those that are formed by the gregarines for gliding motility and to invade target cells [Sibley et al., 1998; Menard, 2001; Meissner et al, 2002] . This makes them an excellent model for studying gliding motility with the goal of creating toxoplasmosis and malaria treatment options.Bibliography
* Heintzelman, M B. 2004. Actin and Myosin in Gregarina polymorpha. Cell Motil Cytoskeleton 58:83-95.
* Menard, R. 2001. Gliding Motility and Cell Invasion by Apicomplexa: Insights from the Plasmodium sporozoite. Cell. Microbiol 3: 63-73.
* Meissner, M, Schluter, D and Soldati, D. 2002. Role of Toxoplasma Gondii Myosin a in Powering Parasite Gliding and Host Cell Invasion. Science 298: 837-841.
* Mitchison, T.J., and Cramer, L.P. 1996. Actin-based cell motility and cell locomotion. Cell 84: 371–379
* Sibley, L.D., Hakansson, S, Carruthers, V. B. 1998. Gliding motility: An efficient mechanism for cell penetration Curr. Biol. 8, 12.
* Walker, M M., C Mackenzie, S P Bainbridge, and C Orme. 1979. A Study of the Structure and Gliding Movement of Gregarina garnhami. J Protozool 26: 566-574.External Links
* [http://tolweb.org/Gregarina/124806 Tree of Life Gregarina]
* [http://tolweb.org/movies/Gregarina/124806 Gregarina Movies]
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