Nuclearia thermophila sp. nov. (Nucleariidae), a new nucleariid species isolated from Yunoko Lake in Nikko (Japan).
A new species of unicellular opisthokont protist, Nuclearia thermophila sp. nov., was isolated from the warm spring water of Yunoko Lake, Japan, and has been described using light and electron microscopy. It exists as a spherical floating form and a flattened amoeboid form showing various shapes. The cells occasionally extended as branches or knobbed filopodia. The spherical form when suspended in medium measured 20-40microm in diameter (excluding filopodia). The amoeboid form may exceed 65microm along the longest axis. A nucleus with an obvious spherical nucleolus, dictyosomes, mitochondria with flat cristae, food vacuoles, and lipid droplet-like vacuoles with homogeneous contents were observed; no extracellular matrix or bacterial endosymbionts were present. The cells ingested flour particles. No cysts were seen. The molecular phylogenetic tree constructed on the basis of the small subunit ribosomal DNA revealed the novelty of N. thermophila and its relationships with previously known nucleariids.
Yoshida
Masaki
M
Research Information Center for Extremophile, Rikkyo (St. Paul's) University, Toshima-ku, Tokyo, Japan. myoshida@rikkyo.ne.jp
Nakayama
Takeshi
T
Inouye
Isao
I
D000818:Animals; D004275:DNA, Ribosomal / Q000235:genetics; D056890:Eukaryota / Q000145:classification* / Q000166:cytology / Q000502:physiology* / Q000648:ultrastructure; D005618:Fresh Water; D007564:Japan; D008969:Molecular Sequence Data; D010587:Phagocytosis / Q000502:physiology; D010802:Phylogeny
D004275:DNA, Ribosomal