Phylogenetic implication of iron-containing superoxide dismutase genes from trichomonad species

Abstract

Abbreviations: SS rRNA, small subunit rRNA; LS rRNA, large subunit rRNA; SOD, superoxide dismutase; Cu/ZnSOD, copper/zinc-containing superoxide dismutase; MnSOD, manganese-containing superoxide dismutase; FeSOD, iron-containing superoxide dismutase; PCR, polymerase chain reaction. *Corresponding author. Tel: + 33 73407472; fax: + 33 73407670. ’ Note: Nucleotide sequence data reported in this paper are available in the GenBank data base under the accession numbers 270665, 270666, 270667, 270668, 270669, 270670, 27067 1, 270672, 270673, 270674, 270675, 270676. transmitted infections in humans [3,4] and Tritrichomonas foetus is recognized as a significant cause of bovine infertility [5]. Comparisons of small subunit (SS) and large subunit (LS) rRNA sequences indicate that trichomonads represent one of the earliest branches in the eukaryotic tree [6-91. The phylogenetic relationships among trichomonads had been first examined by means of morphological characters [ 10,l l] and inferred from SS or LS rRNA sequences [8.9]. The molecular data have generated new hypotheses on the systematics of trichomonads and only some of them are in agreement with morphological analysis. Comparisons of the molecular phylogenies based on LS [S] or SS rRNA sequences [9] revealed the strength of some associations but the position of some species remains unclear indicating a need for sequences of new taxa or the use of other molecular indicators.