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Titolo:
THE EVOLUTIONARY EXPANSION OF THE TRYPANOSOMATID FLAGELLATES
Autore:
VICKERMAN K;
Indirizzi:
UNIV GLASGOW,INST BIOMED & LIFE SCI GLASGOW G12 8QQ LANARK SCOTLAND
Titolo Testata:
International journal for parasitology
fascicolo: 8, volume: 24, anno: 1994,
pagine: 1317 - 1331
SICI:
0020-7519(1994)24:8<1317:TEEOTT>2.0.ZU;2-7
Fonte:
ISI
Lingua:
ENG
Soggetto:
KINETOPLAST DNA; AFRICAN TRYPANOSOMES; LIFE-CYCLE; LEISHMANIA; BRUCEI; PHYTOMONAS; PROTOZOA; EVANSI; TRANSMISSION; GLYCOSOMES;
Keywords:
KINETOPLASTIDA; TRYPANOSOMATIDAE; BODONIDAE; PHYLOGENY; EVOLUTIONARY DIVERGENCE; TRYPANOSOMA; LEISHMANIA; PHYTOMONAS; SEXUAL PROCESSES; ALTRUISM;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
78
Recensione:
Indirizzi per estratti:
Citazione:
K. Vickerman, "THE EVOLUTIONARY EXPANSION OF THE TRYPANOSOMATID FLAGELLATES", International journal for parasitology, 24(8), 1994, pp. 1317-1331

Abstract

The trypanosomatids combine a relatively uniform morphology with ability to parasitise a very diverse range of hosts including animals, plants and other protists. Along with their sister family, the biflagellate bodonids, they are set apart from other eukaryotes by distinctive organisational features, such as the kinetoplast-mitochondrion and RNA editing, isolation of glycolysis enzymes in the glycosome, use of the flagellar pocket for molecular traffic into and out of the cell, a unique method of generating cortical microtubules, and bizarre nuclear organisation. These features testify to the antiquity and isolation of the kinetoplast-bearing flagellates (Kinetoplastida). Molecular sequencing techniques (especially small subunit ribosomal RNA gene sequencing) ale now radically reshaping previous ideas on the phylogeny of theseorganisms. The idea that the monogenetic (MG) trypanosomatids gave rise to the digenetic (DG) genera is losing ground to a view that, afterthe bodonids, the African trypanosomes (DG) represent the most ancient lineage, followed by Trypanosoma cruzi (DG), then Blastocrithidia (MG), Herpetomonas (MG) and Plytomonas (DG), with Leptomonas (MG), Crithidia (MG), Leishmania (DG) and Endotrypanum (DG) forming the crown of the evolutionary tree. Vast genetic distances (12% divergence) separate T. brucei and T. cruzi, while the Leishmania species are separated by very short distances (less than 1% divergence). These phylogenetic conclusions are supported by studies on RNA editing and on the nature of the parasite surface. The trypanosomatids seem to be able to adapt with ease their energy metabolism to the availability of substrates andoxygen, and this may give them the ability to institute new life cycles if host behaviour patterns allow. Sexual processes, though present in at least some trypanosomatids, may have played only a minor part ingenerating diversity during trypanosomatid evolution. On the other hand, the development of altruistic behaviour on the part of some life cycle stages may be a hitherto unconsidered way of maximising fitness in this group. It is concluded that, owing to organisational constraints, the trypanosomatids can undergo substantial molecular variation while registering Very little in the way of morphological change.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 09/04/20 alle ore 05:27:55