Phylogeny of the bodonid flagellates (Kinetoplastida) based on small-subunit rRNA gene sequences.

Abstract

The phylogeny of kinetoplastid flagellates was investigated by determining the sequences of the small-subunit (18S) rRNA from Bodo designis, Bodo saltans K, Bodo saltans P, Bodo sorokini, Bodo sp. (cf. uncinatus), Cruzella marina, Cryptobia helicis, Dimastigella mimosa and Parabodo nitrophilus and analysing these data together with several previously obtained sequences. The root of the kinetoplastid tree was tentatively determined to be attached to the branch of B. designis and/or Cruzella marina. Within this topology, the suborder Trypanosomatina appears as a late-emerging monophyletic group, while the suborder Bodonina is paraphyletic. Within the bodonid subtree, the branches of parasitic organisms were intermingled with free-living ones, implying multiple transitions to parasitism. The tree indicates that the genera Cryptobia and Bodo are artificial taxa. In addition, the separation of the fish cryptobias and Trypanoplasma borreli as different genera was not supported.Keywords : Kinetoplastida, Bodonina, Bodo, Cryptobia, phylogeny INTRODUCTIONStudies of protozoa from the order Kinetoplastida (phylum Euglenozoa) has yielded a large number of unexpected findings, probably more than for any other comparable group of protists ( Vickerman, 1994 ; Donelson et al., 1999). The order has been defined by the presence of a unique organelle, the kinetoplast, which represents a DNA-containing compartment of the single mitochondrion of a cell.These studies have revealed organization of the mitochondrial (kinetoplast) DNA in the form of giant networks, an unusual uridylate insertion\deletion type of RNA editing, intriguingly small kinetoplast rRNAs, Abbreviations : kDNA, kinetoplastid DNA ; LSU large-subunit ; SSU, smallsubunit ; T-PTP, topology-dependent cladistic permutation tail probability.The GenBank accession numbers of the determined SSU rRNA sequences are : AF209856 (B. designis), AF208878 (C. marina), AF208880 (C. helicis), AF208882 (D. mimosa), AF208884 [Bodo sp. (cf. uncinatus)], AF208886 (P. nitrophilus), AF208887 (B. saltans P), AF208888 (B. sorokini ), AF208889 (B. saltans K) ; and of the determined partial LSU rRNA sequences are :importation of all mitochondrial tRNAs from the cytosol, trans-splicing of cytosolic mRNAs, trypanosome surface antigen variation and a novel nucleotide in DNA referred to as base J (reviewed by Donelson et al., 1999) with this list likely to be continued in the future. Due to the early separation of Euglenozoa (Sogin et al., 1986), some of these features could have been directly inherited from the early eukaryotes, while others can represent more recent adaptations, having evolved, for example, as an adaptation to facultative anaerobiosis (Cavalier-Smith, 1997) or even at later stages, as adaptations to parasitism.Based on morphology, Kinetoplastida is traditionally divided into two suborders -Bodonina and Trypanosomatina ( Vickerman, 1976( Vickerman, , 1978Lom, 1979 ;Kivic & Walne, 1984). Members of Trypanosomatina are characterized as obligatory parasitic species with a single ...

Pathogenesis of Chagas' Disease: Parasite Persistence and Autoimmunity

“…In addition, LkDT events have been detected in nonautonomous retroelement SINEs (Alu and MIR) (61%), MER, ERV, and MalR (39%), also constantly found in coding regions showing sequence stretches complementary to LINE primers (115). The kDNA integration events promote the rupture of ORFs of different genes, and therefore, the transfer of mitochondrion DNA from T. cruzi to Chagas' disease patients can have broad physiopathological significance.…”

“…B. saltans is a nonparasitic species included among the bacterivorous kinetoplastid flagellate protozoans especially abundant in organically enriched water. B. saltans diverged early on from the evolutionary line of kinetoplastids, and this species of bodonid is more closely related to the trypanosomatids (115) and is a predecessor of the single-flagellum trypanosomatids that lost the second flagellum in the course of their evolution (59).…”

Phylogeny of the kinetoplastida: taxonomic problems and insights into the evolution of parasitism

“…Only after completion of a more satisfactory survey of this group, will it be possible to propose a comprehensive taxonomic system for this group. The phylogeny of bodonids was investigated in another recent work, which included nine additional bodonid species (Dole•el et al 2000). The root of the tree (Fig.…”

Global Kinetoplastea phylogeny inferred from a large-scale multigene alignment including parasitic species for better understanding transitions from a free-living to a parasitic lifestyle

“…Owing to their importance in public health, the origin of parasitism in the extant trypanosomatids is one of the major questions in the evolution of Kinetoplastea. To address this question, the precise relationship among Neobodonida, Parabodonida, Eubodonida and Trypanosomatida has been explored mainly by analyzing SSU rRNA genes or genes encoding highly conserved proteins, but has not been resolved with high statistical support (Dolezel et al, 2000;Simpson et al, 2002;Moreira et al, 2004;Simpson et al, 2004;von der Heyden et al, 2004;Deschamps et al, 2011). A phylogenetic analysis of 64 genes encoding highly conserved proteins successfully designated Eubodonida as the closest relative of Trypanosomatida (Deschamps et al, 2011).…”