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trypanosome

 
Dictionary: try·pan·o·some   (trĭ-păn'ə-sōm') pronunciation
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n.
Any of various parasitic flagellate protozoans of the genus Trypanosoma, transmitted to the vertebrate bloodstream, lymph, and spinal fluid by certain insects and often causing diseases such as sleeping sickness and nagana.

[From New Latin Trȳpanosōma, genus name : Greek trūpanon, auger (from trūpān, to bore , from trūpē, hole) + Greek sōma, body; see -some3.]

trypanosomal try·pan'o·so'mal or try·pan'o·som'ic (-sŏm'ĭk)

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Columbia Encyclopedia: trypanosome
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trypanosome (trĭp'ənəsōm'), microscopic, one-celled protozoan of the genus Trypanosoma, typically living as an active parasite in the bloodstream of a vertebrate; hundreds of species are known. A trypanosome is long and pointed and possesses a flagellum. The flagellum arises at the front, or anterior, end of the parasite and curves back to form the edge of a long, undulating membrane used in locomotion. Trypanosomes have a complex life cycle; most species undergo part of their development in the digestive tract of insects, which spread the parasite by biting.

Many trypanosomes do not appear to harm their hosts, but a number of species cause serious diseases in humans or domestic animals (see trypanosomiasis). T. gambiense and T. rhodesiensecauses African sleeping sickness and is transmitted by tsetse flies. T. cruzi is the cause of Chagas' disease, prevalent in South and Central America, which affects the nervous system and heart; it is transmitted by the bite of assassin bugs. Other species, restricted in distribution to Africa and Asia, cause diseases of horses and cattle. Control measures include elimination or reduction of the insect carrier populations and measures to reduce the likelihood of bites.

Trypanosomes are classified in the phylum Mastigophora of the kingdom Protista.

Medical Dictionary: try·pan·o·some
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(trĭ-păn'ə-sōm')
n.

A member of the genus Trypanosoma or of the family Trypanosomatidae.

try·pan'o·so'mal or try·pan'o·som'ic (-sŏm'ĭk) adj.
Veterinary Dictionary: trypanosome
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A protozoan of the genus Trypanosoma.

Wikipedia: Trypanosome
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Trypanosomes
Trypanosoma cruzi parasites
Scientific classification
Domain: Eukaryota
Kingdom: Excavata
Phylum: Euglenozoa
Subphylum: Mastigophora
Class: Kinetoplastea
Order: Trypanosomatida
Genera

Blastocrithidia
Crithidia
Endotrypanum
Herpetomonas
Leishmania
Leptomonas
Phytomonas
Trypanosoma
Wallaceina

Trypanosomes are a group of kinetoplastid protozoa distinguished by having only a single flagellum. All members are exclusively parasitic, found primarily in insects.[1] A few genera have life-cycles involving a secondary host, which may be a vertebrate or a plant. These include several species that cause major diseases in humans.[2]

The most important trypanosomal diseases are trypanosomiasis (African Sleeping Sickness and South American Chagas Disease); these are caused by species of Trypanosoma. The Leishmaniases are a set of trypanosomal diseases caused by various species of Leishmania.

A variety of different forms appear in the life-cycles of trypanosomes, distinguished mainly by the position of the flagellum:

Amastigote (leishmanial) - reduced or absent
Promastigote (leptomonad) - anterior of nucleus, free from cell body
Epimastigote (crithidial) - anterior of nucleus, connected by a short undulating membrane
Opisthomastigote (herpetomonad) - posterior of nucleus, passing through a long groove in the cell
Trypomastigote (trypanosomal) - posterior of nucleus, connected by a long undulating membrane

Most trypanosomes have at least amastigote and promastigote stages. Trypanosoma appears in all five forms, with the trypanosomal stage occurring in the vertebrate host. Trypanosoma brucei sub-species have two forms in the bloodstream of a vertebrate host, the rapidly dividing long-slender form and the non-dividing short stumpy form. The short stumpy parasites are adapted for uptake into the tsetse fly vector, and are non-proliferative in comparison with the slender forms.

Unique to the African trypanosome Trypansoma brucei is the expression of a variable surface glycoprotein (VSG) coat on the cell surface, which undergoes constant variation in order to evade the humoral immune system and host antibodies. It is thought that recombination via double-stranded DNA breaks from a repertoire of about 100 complete VSG genes, and a large number of VSG-related sequences, is responsible for the vast diversity of the parasite.[3] This recombination would retain effectiveness in immune evasion by maintaining diversity.

The acidocalcisome organelle was first identified in trypanosomes. [4]

A notable characteristic of trypanosomes is that they are able to perform Trans-splicing.

References

  1. ^ Podlipaev S (May 2001). "The more insect trypanosomatids under study-the more diverse Trypanosomatidae appears". Int. J. Parasitol. 31 (5-6): 648–52. doi:10.1016/S0020-7519(01)00139-4. PMID 11334958. 
  2. ^ Simpson AG, Stevens JR, Lukes J (April 2006). "The evolution and diversity of kinetoplastid flagellates". Trends Parasitol. 22 (4): 168–74. doi:10.1016/j.pt.2006.02.006. PMID 16504583. 
  3. ^ Taylor JE, Rudenko G (November 2006). "Switching trypanosome coats: what's in the wardrobe?". Trends Genet. 22 (11): 614–20. doi:10.1016/j.tig.2006.08.003. PMID 16908087. 
  4. ^ http://www.nature.com/nrmicro/journal/v3/n3/full/nrmicro1097.html Nature Reviews Microbiology 3, 251-261 (March 2005) | doi:10.1038/nrmicro1097 Acidocalcisomes? Conserved from bacteria to man? Roberto Docampo, Wanderley de Souza, Kildare Miranda, Peter Rohloff Silvia N. J. Moreno

External links

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Excavata
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This entry is from Wikipedia, the leading user-contributed encyclopedia. It may not have been reviewed by professional editors (see full disclaimer)

 
 

 

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Dictionary. The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.  Read more
Columbia Encyclopedia. The Columbia Electronic Encyclopedia, Sixth Edition Copyright © 2003, Columbia University Press. Licensed from Columbia University Press. All rights reserved. www.cc.columbia.edu/cu/cup/.  Read more
Medical Dictionary. The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company.  Read more
Veterinary Dictionary. Saunders Comprehensive Veterinary Dictionary 3rd Edition. Copyright © 2007 by D.C. Blood, V.P. Studdert and C.C. Gay, Elsevier. All rights reserved.  Read more
Wikipedia. This article is licensed under the Creative Commons Attribution/Share-Alike License. It uses material from the Wikipedia article "Trypanosome".  Read more