CULTURE AND PHYLOGENETIC CHARACTERIZATION OF TRICHOMITUS-TRYPANOIDES DUBOSCQ AND GRASSE 1924, N-COMB - A TRICHOMONAD FLAGELLATE ISOLATED FROM THE HINDGUT OF THE TERMITE RETICULITERMES-SANTONENSIS FEYTAUD

A trichomonad flagellate strain R1 was isolated from the hindgut conte nts of the termite Reticulitermes santonensis Feytaud. The flagellate was cultivated at 28 degrees C in anaerobic medium containing yeast ex tract, minerals and vitamins. The isolate fed on living bacteria. It s howed the typical morphological and ultrastructural features of the tr ichomonads, closely resembling Trichomitus trypanoides. In order to de termine its phylogenetic position the small subunit ribosomal DNA (SSU rDNA) of the flagellate was amplified in vitro using the polymerase c hain reaction (PCR), cloned in a plasmid vector and sequenced. Compari son of the obtained sequence with so far available SSU rRNA/rDNA seque nces showed strongest similarity (89%) to the sequence of Tritrichomon as foetus. The phylogenetic analysis with parsimony and distance matri x methods placed Trichomitus trypanoides strain R1 near by the root of the phylogenetically so far analyzed eukaryotic organisms. This confi rms that termites harbour hindgut symbionts, which originate from very early evolved eukaryotes.