Identification of the ectosymbiotic bacteria of Mixotricha paradoxa involved in movement symbiosis

Symbionts of the gut flagellate Staurojoenina sp. from Neotermes cubanus represent a novel, termite-associated lineage of Bacteroidales: description of ‘Candidatus Vestibaculum illigatum’

“…The ultrastructure of the junctional complexes is completely different from that of the motility symbionts of Caduceia versatilis (Tamm, 1980;d'Ambrosio et al, 1999), and only remotely resembles the situation of the second epibiont of M. paradoxa (Cleveland & Grimstone, 1964;Wenzel et al, 2003). It is likely that also the nature of the association between Staurojoenina species and their epibiotic bacteria differs from those examples.…”

“…Interestingly, the epibionts of Staurojoenina sp. fall into the same cluster of the Bacteroidales as one of the two epibionts of the trichomonad flagellate Mixotricha paradoxa from Mastotermes darwiniensis (Wenzel et al, 2003).…”

“…Cleveland & Grimstone (1964) provided an elegant description of the fascinating motility symbiosis between Mixotricha paradoxa and its epibiotic spirochaetes, which were recently identified as members of the Treponema cluster by 16S rRNA gene sequence analysis (Wenzel et al, 2003). Mixotricha paradoxa, which occurs only in the gut of Mastotermes darwiniensis, is propelled by the helical undulations of the spirochaetes adhering to the host membrane through specialized cell junctions.…”

“…2), the clone from Staurojoenina sp. always fell within a cluster of clones comprising Bacteroides-related sequences from other termites (Cluster 4; Ohkuma et al, 2002), which also included the rodshaped symbiont of the trichomonad flagellate Mixotricha paradoxa (Wenzel et al, 2003). The closest cultivated relative was the human oral bacterium Tannerella forsythensis, although the sequence similarity was rather low (<85 %).…”

“…The presence of special attachment sites on the cell envelope of the flagellates (Smith & Arnott, 1974;Tamm, 1980;Radek et al, 1992Radek et al, , 1996 indicate tight interactions, but only in the case of Mixotricha paradoxa (Cleveland & Grimstone, 1964) and a devescovinid flagellate (Tamm, 1982), has a function of the epibionts in the motility of the host cell been demonstrated. Apart from some epibiotic spirochaetes (Iida et al, 2000;Noda et al, 2003) of several other gut flagellates, the epibionts of M. paradoxa (Wenzel et al, 2003) are also among the few instances where the phylogenetic affiliation of the prokaryotic partner has been substantiated (Dolan, 2001). …”