無腸動物Waminoa sp. の人工飼育と産卵法

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1 Waminoa sp. Artificial rearing and oviposition of Waminoa sp. (Acoela, Acoelomorpha): Toward the development of a model system to study animal-algal symbiosis. Tomoe Hikosaka-KATAYAMA 1 and Akira HIKOSAKA 2 1 Center for Gene Science, Hiroshima University 2 Graduate School of Integrated Arts and Sciences, Hiroshima University Abstract: Waminoa sp. is an acoelomorph worm that infests corals and harbors two species of dinoflagellates, Amphidinium sp. and Symbiodinium sp.. These symbiotic algae are inherited vertically from parent to offspring during oogenesis. In this study, we established a method for artificial breeding of Waminoa sp., as the first step toward using Waminoa sp. in the study of the mechanism underlying animal algal symbiosis and the evolution of this symbiosis. We developed a system in which an aquarium circulated approximately 80 L of artificial seawater between an upper aquarium and a lower sump, each of which was 45 cm 30 cm 35 cm in size and contained 40 L of seawater. Water flowed into the upper aquarium from the sump alternately through a pipe outlet. The upper aquarium contained the hard coral Symphyllia valenciennesii, live rocks, and a layer of fine sand. A 150-W metal halide lamp was suspended over the aquarium to aid photosynthesis. The system was maintained at a salinity of ppt and a temperature of 23 C, on a 14-h light (17 50 μmol quanta m -2 s -1 ) : 10-h dark photoperiod. We succeeded in producing almost every stage of the life cycle of Waminoa sp., including the zygote, embryo, larva, juvenile, and adult stages, independent of seasons. In addition, we developed an artificial oviposition procedure that involved isolation from coral in the mature stage. The system developed in this study will serve as a foundation for future studies on acoel algal symbiosis. Key Words: Symbiosis, Acoelomorpha, Symbiodinium, Amphidinium, oogenesis, oviposition.

Margulis, 1993 (Katayama et al., 1993 Baguñà and Riutort, 2004) Acoelomorpha Tetraselmis Amphidinium Yamasu, 1987 (Hyman, 1951) Douglas, 1994 Waminoa Barneah et al.

2 Margulis, 1993 (Katayama et al., 1993 Baguñà and Riutort, 2004) Acoelomorpha Tetraselmis Amphidinium Yamasu, 1987 (Hyman, 1951) Douglas, 1994 Waminoa Barneah et al., 2007a Haapkylä et al., Waminoa spp., 2010Waminoa Amphidinium Symbiodinium Winsor, 1990 Waminoa W. brickneri Barneah et al., 2007b Waminoa Waminoa Waminoa spp. Waminoa spp.

45cm x 30 cm x 35 cm 10kg EHEIM, 20L (, zc-500e)

3 Waminoa Waminoa Waminoa sp. Symphyllia valenciennesii 20cm Web Room210, cm x 30 cm x 35 cm 10kg EHEIM, 20L (, zc-500e) LiveSea salt, EHEIM 150W / 14/ μmol quanta m -2 s -1 1 CO L

Waminoa Waminoa 50ml Leica MZFL III 10 MgCl 2 Waminoa 25 0.5 23 23 50ml / 14/10 35μmol quanta m -2 s -1 25 LH-40CCFL-TMCT 25 Nikon LABOPHOTO-2 Waminoa sp.

4 Waminoa Waminoa 50ml Leica MZFL III 10 MgCl 2 Waminoa ml / 14/10 35μmol quanta m -2 s LH-40CCFL-TMCT 25 Nikon LABOPHOTO-2 Waminoa sp. Waminoa sp. 18 Waminoa sp. Waminoa 60 Waminoa sp. 2.5mm2mm (4A) Waminoa sp. (4B) Amphidinium sp. Symbiodinium sp. (4C) Waminoa sp. 4A 4A Waminoa brickneri

5 Waminoa (5A) (5B) Symbiodinium sp. (5C) (5D) 50μm 4B) 18 25μm Amphidinium sp. 7 11μm Symbiodinium sp. Waminoa Waminoa 25 Praesagittifera naikaiensis 1997Waminoa sp. Waminoa23 4C 25 ( 5A 5B) 15 Waminoa Henry et al B ( 5C)

6 20 ( 5D) Waminoa sp. 25 (McCoy and Balzer, 2002) Waminoa Waminoa sp. ROOM210 Waminoa sp. NBARD Waminoa C CAPWR Baguñà, J., Riutort, M Molecular phylogeny of the Platyhelminthes. Canadian Journal of Zoology, 82, Barneah, O., Brickner, I., Hooge, M., Weis, V.M., Benayahu, Y. 2007b. First evidence of maternal transmission of algal Barneah, O., Brickner, I., Hooge, M., Weis, V.M., endosymbionts at an oocyte stage in a triploblastic host, LaJeunesse, T.C., Benayahu, Y. 2007a. Three party with observations on reproduction in Waminoa brickneri symbiosis: acoelomorph worms, corals and unicellular (Acoelomorpha). Invertebrate Biology, 126, algal symbionts in Eilat (Red Sea). Marine Biology, 151, Douglas, A.E Symbiotic Interactions. Oxford

7 Waminoa University Press. New York. Haapkylä, J., Seymour, A.S., Barneah, O., Brickner, I., Hennige, S., Suggett, D., Smith, D Association of Waminoa sp. (Acoela) with corals in the Wakatobi Marine Park, South-East Sulawesi, Indonesia. Marine Biology, 156, Henry, J.Q., Martindale, M.Q., Boyer, B.C The unique developmental program of the Acoel flatworm, Neochildia fusca. Developmental Biology, 220, Hyman, L.H The Invertebrates: Platyhelminthes and Rhynchocoela; the Acoelomate Bilateria. McGraw-Hill, New york: pp Katayama, T., Yamamoto, M., Wada, H., Satoh, N Phylogenetic position of acoel turbellarians inferred from partial 18S rdna sequences. Zoological Science, 10, Margulis, L Symbiosis in Cell Evolution 2nd ed McCoy, A.M., Balzer, I Algal symbiosis in flatworms. In: Symbiosis: Mechanisms and Model Systems. Seckbach J, ed., pp Kluwer Academic Publishers, Dordrecht, The Netherlands Ogunlana, M., Hooge, M., Tekle, Y.I., Benayahu, Y., Barneah, O., Tyler, S Waminoa brickneri n. sp. (Acoela: Acoelomorpha) associated with corals in the Red Sea. Zootaxa, 1008, Room210 (Web site). URL: cool.ne.jp/articles.html ( ). Winsor, L Marine Turbellaria (Acoela) from North Queensland. Memoirs of the Queensland Museum, 28, Yamasu, T., Okazaki, A Preliminary faunal list of acoel turbellarian species from the Ryukyu islands. Garaxia, 6,

* Meso- -scale Features of the Tokai Heavy Rainfall in September 2000 Shin-ichi SUZUKI Disaster Prevention Research Group, National R

38 2002 7 2000 9 * Meso- -scale Features of the Tokai Heavy Rainfall in September 2000 Shin-ichi SUZUKI Disaster Prevention Research Group, National Research Institute for Earth Science and Disaster Prevention,