title: Genetic diversity of microbial eukaryotes in anoxic sediment around fumaroles on a submarine caldera floor based on the small-subunit rDNA phylogeny.
abstract: Recent culture-independent molecular analyses have shown the diversity and ecological importance of microbial eukaryotes (protists) in various marine environments. In the present study we directly extracted DNA from anoxic sediment near active fumaroles on a submarine caldera floor at a depth of 200 m and constructed genetic libraries of PCR-amplified eukaryotic small-subunit (SSU) rDNA. By sequencing cloned SSU rDNA of the libraries and their phylogenetic analyses, it was shown that most sequences have affiliations with known major lineages of eukaryotes (Cercozoa, Alveolata, stramenopiles and Opisthokonta). In particular, some sequences were closely related to those of representatives of eukaryotic parasites, such as Phagomyxa and Cryothecomonas of Cercozoa, Pirsonia of stramenopiles and Ichthyosporea of Opisthokonta, although it is not clear whether the organisms occur in free-living or parasitic forms. In addition, other sequences did not seem to be related to any described eukaryotic lineages suggesting the existence of novel eukaryotes at a high-taxonomic level in the sediment. The community composition of microbial eukaryotes in the sediment we surveyed was different overall from those of other anoxic marine environments previously investigated.
authors.affiliation: Japan Agency for Marine-Earth Science and Technology (JAMSTEC), 2-15 Natsushima, Yokosuka, Kanagawa 237-0061, Japan. takishitak@jamstec.go.jp
authors.forename: Kiyotaka
authors.initials: K
authors.lastname: Takishita
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Miyake
authors.forename: Masaru
authors.initials: M
authors.lastname: Kawato
authors.forename: Tadashi
authors.initials: T
authors.lastname: Maruyama
mesh_terms: D000818:Animals; D003001:Cloning, Molecular; D017931:DNA Primers; D004275:DNA, Ribosomal / Q000235:genetics*; D004777:Environment; D056890:Eukaryota / Q000145:classification / Q000235:genetics*; D014644:Genetic Variation; D019015:Geologic Sediments; D000860:Hypoxia; D010802:Phylogeny; D012623:Seawater
chemical_list: D017931:DNA Primers; D004275:DNA, Ribosomal
references.citation: Mol Biol Evol. 1997 May;14(5):498-505
references.pmid: 9159927
references.citation: Nature. 2002 May 9;417(6885):137
references.pmid: 12000949
references.citation: Mol Biol Evol. 1987 Jul;4(4):406-25
references.pmid: 3447015
references.citation: Nature. 2001 Feb 1;409(6820):607-10
references.pmid: 11214317
references.citation: Appl Environ Microbiol. 2003 May;69(5):2657-63
references.pmid: 12732534
references.citation: Protist. 2003 Oct;154(3-4):341-58
references.pmid: 14658494
references.citation: Mol Biol Evol. 1993 May;10(3):512-26
references.pmid: 8336541
references.citation: Evolution. 1985 Jul;39(4):783-791
references.pmid: 28561359
references.citation: Proc Natl Acad Sci U S A. 2002 May 28;99(11):7658-62
references.pmid: 12032339
references.citation: Int J Syst Evol Microbiol. 2003 Jan;53(Pt 1):289-93
references.pmid: 12656186
references.citation: Proc Natl Acad Sci U S A. 2002 Jun 11;99(12):8324-9
references.pmid: 12060775
references.citation: Proc Natl Acad Sci U S A. 2003 Jan 21;100(2):697-702
references.pmid: 12522264
references.citation: Appl Environ Microbiol. 2002 Sep;68(9):4554-8
references.pmid: 12200313
references.citation: Appl Environ Microbiol. 2003 Sep;69(9):5656-63
references.pmid: 12957957
references.citation: Bioinformatics. 1998;14(9):817-8
references.pmid: 9918953
references.citation: Science. 1999 Aug 13;285(5430):1025-6
references.pmid: 10475845
references.citation: Nucleic Acids Res. 2001 Jan 1;29(1):173-4
references.pmid: 11125082
references.citation: Appl Environ Microbiol. 2001 Jul;67(7):2932-41
references.pmid: 11425705
references.citation: BMC Biol. 2004 Jun 04;2:13
references.pmid: 15176975
references.citation: Nucleic Acids Res. 1994 Nov 11;22(22):4673-80
references.pmid: 7984417
references.citation: Appl Environ Microbiol. 2004 Jun;70(6):3528-34
references.pmid: 15184153
references.citation: Syst Biol. 2001 Aug;50(4):525-39
references.pmid: 12116651
references.citation: Trends Parasitol. 2003 Dec;19(12):556-8
references.pmid: 14642764
references.citation: Nature. 2001 Feb 1;409(6820):603-7
references.pmid: 11214316
references.citation: Protist. 2001 May;152(1):43-51
references.pmid: 11401036