title: Taxonomic study of a new eustigmatophycean alga, Vacuoliviride crystalliferum gen. et sp. nov.
abstract: This study investigated the taxonomic affiliation of the algal strain nak-9, which has been reported to absorb radioactive cesium with high efficiency, using light and electron microscopy, and molecular phylogenetic analysis based on 18S ribosomal RNA gene (rDNA) sequences. This alga is spherical and coccoid, with a smooth cell wall, large vacuole, crystalline structure, reddish globule, and refractile granules (lamellate vesicles). The cells possess one to several greenish parietal chloroplasts with a bulging pyrenoid surrounded by lamellate vesicles. The chloroplasts include orderly thylakoid lamellae but no girdle lamella. Molecular phylogenetic analysis suggests that strain nak-9 is a member of the eustigmatophycean clade, which includes Goniochloris, Pseudostaurastrum, and Trachydiscus. On the basis of these results, we propose that strain nak-9 (NIES-2860) comprises a new species and new genus of the Eustigmatophyceae, Vacuoliviride crystalliferum gen. et sp. nov.
authors.affiliation: Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki, 305-8572, Japan, algae@biol.tsukuba.ac.jp.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Nakayama
authors.forename: Atsushi
authors.initials: A
authors.lastname: Nakamura
authors.forename: Akiko
authors.initials: A
authors.lastname: Yokoyama
authors.forename: Takashi
authors.initials: T
authors.lastname: Shiratori
authors.forename: Isao
authors.initials: I
authors.lastname: Inouye
authors.forename: Ken-Ichiro
authors.initials: K
authors.lastname: Ishida
mesh_terms: D020418:Algal Proteins / Q000235:genetics; D002736:Chloroplasts / Q000648:ultrastructure; D008969:Molecular Sequence Data; D010802:Phylogeny; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D017422:Sequence Analysis, DNA; D058009:Stramenopiles / Q000145:classification* / Q000166:cytology / Q000235:genetics* / Q000648:ultrastructure
chemical_list: D020418:Algal Proteins; D012337:RNA, Ribosomal, 18S