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Post by aqt on Jan 15, 2010 17:47:12 GMT -5
The Apicomplexa are a large group of protists, most of which possess a unique organelle called apicoplast and an apical complex structure involved in penetrating a host's cell. They are unicellular, spore-forming, and exclusively[1] parasites of animals. Motile structures such as flagella or pseudopods are absent except in certain gamete stages. This is a diverse group including organisms such as coccidia, gregarines, piroplasms, haemogregarines, and plasmodia; some diseases caused by apicomplexan organisms include: Babesiosis (Babesia) Malaria (Plasmodium) Coccidian diseases including: Cryptosporidiosis (Cryptosporidium parvum) Cyclosporiasis (Cyclospora cayetanensis) Isosporiasis (Isospora belli) Toxoplasmosis (Toxoplasma gondii) en.wikipedia.org/wiki/Apicomplexaback to basics? aqt
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Post by aqt on Jan 15, 2010 17:55:48 GMT -5
Evidence suggests that the apicoplast is a product of secondary endosymbiosis,[3] and that the apicoplast may be homologous to the secondary plastid of the closely related dinoflagellate algae. An ancient cyanobacterium was first engulfed by a eukaryotic cell but was not digested. The bacterium escaped being digested because it formed a symbiotic relationship with the host eukaryotic cell; both the eukaryote and the bacterium mutually benefited from their novel shared existence.[4] The result of the primary endosymbiosis was a photosynthetic eukaryotic alga. A descendent of this eukaryotic alga was then itself engulfed by a heterotrophic eukaryote with which it formed its own symbiotic relationship and was preserved as a plastid.[5] The apicoplast plastid evolved in its new role to preserve only those functions and genes necessary to beneficially contribute to the host-organelle relationship. The ancestral genome of more than 150 kb was reduced through deletions and rearrangements to its present 35 kb size.[1] During the reorganization of the plastid the apicoplast lost its nucleus and, most notably, its ability to photosynthesize.[5] These losses of function are hypothesized to have occurred at an early evolutionary stage in order to have allowed sufficient time for the complete degradation of acknowledged photosynthetic relicts[1] and the disappearance of a nucleomorph en.wikipedia.org/wiki/Apicoplast
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Post by aqt on Jan 15, 2010 18:03:56 GMT -5
The apical complex is a set of secretory and cytoskeletal structures that enables the young parasite to enter a host cell. It consists of several components: two apical rings a conoid - an open cone of spiral rod-like elements polar wing of dense granular material that connects the ends of the longitudinal cytoskeletal microtubules rhoptries and micronemes. These are modified secretory vesicles. www.zoology.ubc.ca/courses/bio332/sporozoa_notes.htmReproduction in apicomplexans: Cell growth (A and B) occurs prior to division. Division takes place through several rounds of mitosis without cytokinesis (C) followed by multiple cleavage (D) resulting in the simultaneous production of a set of progeny cells (E). Typical apicomplexan life cycle. The three points at which multiple fission occurs (Merogony, Gamogony and Sporogony) are indicated in boxes. The principal stages are shown in bold type. Gamogony is the process where by a gamont gives rise to many gametes. Sporogony is the process whereby a single zygote gives rise to many spores or sporozoites. Sporozoites are small cells that lie within the thickwalled resistant spore. Merogony is a process that increases the number of infective cells. A single large schizont gives rise to a large number of small merozoites that infect other host cells. Why do you think that this might be of benefit to a parasite? Merogony is not present in all life histories. The relative importance of increase in cell numbers at gamogony and at sporogony also varies between different groups of apicomplexans and between species. While there is a common general life cycle pattern, there is lots of variation in life history. There are two major groups of apicomplexans, Gregarines and Coccidia.
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Post by skyship on Jan 15, 2010 21:41:45 GMT -5
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Post by skyship on Jan 15, 2010 22:22:22 GMT -5
Isospora Belli Masking as cancer or is it Cancer? seems to reproduce not replicate. as cancer does.? In all of our endeavors, little talk of parasites? in the papers, it is all about genes? ==================== seems isospora and typanasoma have the mitochondria?................ found a 3d display of growth of euglena, euglena and trypanasoma have mito acting as organells, but they can build a 3 dimensional organism. Symbiosis. will post later. ======================== check this out, can't get but, oh well: from google: BioOne Online Journals - MOLECULAR PHYLOGENY OF THE OTHER TISSUE ... by JR Barta - 2001 - Cited by 20 - Related articles - All 9 versions The Isospora species containing Stieda bodies were found to group with the .... Dating of the human-ape splitting by a molecular clock of mitochondrial DNA. ... www.bioone.org/.../0022-3395(2001)087%5B0121:MPOTOT%5D2.0.CO%3B2============================== What are stiedia bodies? ============================ in relations to trypanasoma: There seems to be a new trypanasoma evansii in India, could that one simply be our parasite? Why is it all of a sudden new in India? mmmmmmm written in 2005: why the report from Switz and France? bit odd, but we have seen worse! www.ajtmh.org/cgi/reprint/73/3/491.pdfEvans found some in 1901 books.google.com/books?id=YwspAAAAYAAJ&pg=PA318&lpg=PA318&dq=trypanosoma+evansii+first+case+in+India&source=bl&ots=mr5l4ZaAss&sig= tgjk8v1IAklSBm-cTgPhGhLAf3w#v=onepage&q=trypanosoma%20evansii%20 first%20case%20in%20India&f=false
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