title: Phylogenetic position of Blastocystis hominis and of stramenopiles inferred from multiple molecular sequence data.
abstract: Blastocystis hominis, a parasite of the human intestine, has recently been positioned within stramenopiles by the small subunit rRNA phylogeny. To further confirm its phylogenetic position using multiple molecular sequence data, we determined the nucleotide sequences putatively encoding small subunit ribosomal RNA, cytosolic-type 70-kDa heat shock protein, translation elongation factor 2, and the non-catalytic 'B' subunit of vacuolar ATPase of B. hominis (HE87-1 strain). Moreover, we determined the translation elongation factor 2 sequence of an apicomplexan parasite, Plasmodium falciparum, that belongs to alveolates. The maximum likelihood analyses of small subunit rRNA and cytosolic-type 70-kDa heat shock protein clearly demonstrated that B. hominis (HE87-1 strain) is positioned within stramenopiles, being congruent with the previous small subunit rRNA analysis, including the sequences of B. hominis (Nand strain) and a Blastocystis isolate from guinea pig. Although no clear resolution among major eukaryotic groups was obtained by the individual phylogenies based on the four molecules analyzed here, a combined analysis of various molecules, including these, clearly indicated that Blastocystis/stramenopiles are the closest relatives of alveolates.
authors.affiliation: Department of Biosystems Science, The Graduate University for Advanced Studies (Sokendai), Hayama, Kanagawa, Japan.
authors.forename: Nobuko
authors.initials: N
authors.lastname: Arisue
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Hashimoto
authors.forename: Hisao
authors.initials: H
authors.lastname: Yoshikawa
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Nakamura
authors.forename: Gen
authors.initials: G
authors.lastname: Nakamura
authors.forename: Fuminori
authors.initials: F
authors.lastname: Nakamura
authors.forename: Taka-Aki
authors.initials: TA
authors.lastname: Yano
authors.forename: Masami
authors.initials: M
authors.lastname: Hasegawa
mesh_terms: D000818:Animals; D016844:Blastocystis / Q000235:genetics*; D003001:Cloning, Molecular; D056890:Eukaryota / Q000235:genetics*; D018840:HSP70 Heat-Shock Proteins / Q000032:analysis / Q000235:genetics; D006801:Humans; D008969:Molecular Sequence Data; D020652:Peptide Elongation Factor 2 / Q000032:analysis / Q000235:genetics; D010802:Phylogeny; D010963:Plasmodium falciparum / Q000235:genetics / Q000302:isolation & purification; D012313:RNA / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D016053:RNA, Protozoan / Q000032:analysis*; D016415:Sequence Alignment; D017423:Sequence Analysis, RNA; D025262:Vacuolar Proton-Translocating ATPases / Q000032:analysis / Q000235:genetics
chemical_list: D018840:HSP70 Heat-Shock Proteins; D020652:Peptide Elongation Factor 2; D016053:RNA, Protozoan; D012313:RNA; D025262:Vacuolar Proton-Translocating ATPases