Jakoba liberaAlastair Simpson
Jakoba is a group of jakobid flagellates. At present there is a single described species, Jakoba libera (Ruinen, 1938) Patterson, 1990.
Jakoba incarcerata described by Bernard et al. 2000 has now been renamed Andalucia incarcerata (Lara et al., 2006), while 'Jakoba bahamensis' / 'Jakoba bahamiensis' is not formally described. In fact, molecular phylogenies indicate that neither are specifically related to Jakoba libera (Simpson et al., 2002; Lara et al., 2006; Rodriguez-Ezpeleta, 2007; Simpson et al., 2008; Hampl et al. unpublished).
There are two cultures identified as Jakoba libera for which small subunit ribosomal RNA gene sequences are available - ATCC 50422 and WHOI DB9. The sequences are 95% identical, and are always recovered as a clade relative to other jakobids (Cavalier-Smith, 2003; Lara et al., 2006). The Jakoba libera morphospecies, so far, therefore, appears to be a clade.
Jakoba libera is a bacterivorous flagellate with two flagella. It is free-swimming, but often attaches to surfaces by the anterior flagellum during feeding. As in other jakobids, and many other excavates, the posterior flagellum beats within a broad ventral groove. The current generated by the flagellum draws suspended prokaryotes into the groove, where they are phagocytosed.
Jakoba libera has been reported from marine samples, and from hypersaline sites (Patterson, 1990; Ruinen, 1938).
The mitochondrial genome of Jakoba libera, while still remarkably gene-rich, includes fewer genes than other jakobid mitochondrial genomes studied to date (Gray et al., 2004). For example, only two subunits of eubacterial-type RNA polymerase are encoded by the mitochondrial genome, whereas other jakobids (e.g. Reclinomonas americana) have four mitochondrially-encoded subunits.
Bernard, C., Simpson, A. G. B. & Patterson, D. J. (2000) Some free-living flagellates (Protista) from anoxic habitats. Ophelia 52: 113-142.
Cavalier-Smith, T. (2003) The excavate protozoan phyla Metamonada Grasse emend. (Anaeromonadea, Parabasalia, Carpediemonas, Eopharyngia) and Loukozoa emend. (Jakobea, Malawimonas): their evolutionary affinities and new higher taxa. Int. J. Syst. Evol. Microbiol. 53: 1741-1758.
Gray, M. W., Lang, B. F. & Burger, G. (2004) Mitochondria of protists. Annu. Rev. Genet. 38: 477-525.
Lara, E., Chatzinotas, A., Simpson, A.G.B. (2006) Andalucia (gen. nov,): a new taxon for the deepest branch within jakobids (Jakobida; Excavata), based on morphological and molecular study of a new flagellate from soil. J. Eukaryot. Microbiol. 53: 112-120.
O’Kelly, C. J. (1993) The jakobid flagellates: structural features of Jakoba, Reclinomonas and Histiona and implications for the early diversification of eukaryotes. J. Eukaryot. Microbiol. 40: 627--636.
Patterson, D.J. (1990) Jakoba libera (Ruinen, 1938), a heterotrophic flagellate from deep oceanic sediments. J. Mar. Biol. Ass. U.K. 70: 381-393.
Patterson, D.J., Vørs, N., Simpson, A.G.B. & O'Kelly, C.J. (2002) Residual and predatory heterotrophic flagellates. In: Lee, J.J., Leedale, G.F.& Bradbury P. (ed.) An illustrated guide to the protozoa, second edition. pp 1302-1328. Society of Protozoologists, Lawrence, Kansas.
Rodríguez-Ezpeleta, N., Brinkmann, H., Burger, G., Roger, A.J., Gray, M.W., Philippe, H., Lang, B.F. (2007) Toward resolving the eukaryotic tree: The phylogenetic positions of jakobids and cercozoans. Curr. Biol. 17: 1420-1425.
Ruinen J. (1938) Notizen über Salzflagellaten. II. Über die Verbereitung der Salzflagellaten. Arch Protistenkd 90: 210-258.
Simpson, A.G.B., Roger, A.J., Silberman, J.D., Leipe, D.D., Edgcomb, V.P., Jermiin, L.S., Patterson, D.J. & Sogin, M.L. (2002) Evolutionary history of “early diverging” eukaryotes: the excavate taxon Carpediemonas is a close relative of Giardia. Mol. Biol. Evol. 19: 1782-1791.
Simpson, A.G.B., Perley, T. & Lara, E., (2008) Lateral transfer of the gene for a widely used marker, alpha tubulin, indicated by a multi-protein study of the phylogenetic position of Andalucia (Excavata). Mol. Phylogenet. Evol. 47: 366-377.
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Dalhousie University, Halifax, Nova Scotia, Canada
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- First online 05 September 2008
- Content changed 05 September 2008
Citing this page:
Simpson, Alastair. 2008. Jakoba http://tolweb.org/Jakoba_libera/97415/2008.09.05 in The Tree of Life Web Project, http://tolweb.org/. Jakoba libera . Version 05 September 2008.