@article {1731, title = {The identification of ᴅ-tryptophan as a bioactive substance for postembryonic ovarian development in the planarian Dugesia ryukyuensis}, journal = {Scientific Reports}, volume = {7}, year = {2017}, month = {2017/03/24/online}, pages = {45175 - }, publisher = {The Author(s)}, url = {http://dx.doi.org/10.1038/srep45175}, author = {Kobayashi, Kazuya and Maezawa, Takanobu and Tanaka, Hiroyuki and Onuki, Hiroyuki and Horiguchi, Yurie and Hirota, Hiroshi and Ishida, Tetsuo and Horiike, Kihachiro and Agata, Yasutoshi and Aoki, Manabu and Hoshi, Motonori and Matsumoto, Midori} } @article {669, title = {The Dugesia ryukyuensis database as a molecular resource for studying switching of the reproductive system}, journal = {Zoological Science}, volume = {24}, number = {1}, year = {2007}, month = {01/2007}, pages = {31-37}, publisher = {Zoological Society of Japan}, abstract = {

The planarian Dugesia ryukyuensis reproduces both asexually and sexually, and can switch from one mode of reproduction to the other. We recently developed a method for experimentally switching reproduction of the planarian from the asexual to the sexual mode. We constructed a cDNA library from sexualized D. ryukyuensis and sequenced and analyzed 8,988 expressed sequence tags (ESTs). The ESTs were analyzed and grouped into 3,077 non-redundant sequences, leaving 1,929 singletons that formed the basis of unigene sets. Fifty-six percent of the cDNAs analyzed shared similarity (E-value\<1E -20) with sequences deposited in NCBI. Highly redundant sequences encoded granulin and actin, which are expressed in the whole body, and other redundant sequences encoded a Vasa-like protein, which is known to be a component of germ-line cells and is expressed in the ovary, and Y-protein, which is expressed in the testis. The sexualized planarian expressed sequence tag database (http://planaria.bio.keio.ac.jp/planaria/) is an open-access, online resource providing access to sequence, classification, clustering, and annotation data. This database should constitute a powerful tool for analyzing sexualization in planarians.

}, doi = {http://dx.doi.org/10.2108/zsj.24.31}, url = {http://www.bioone.org/doi/abs/10.2108/zsj.24.31}, author = {Hideyuki Ishizuka and Takanobu Maezawa and Junpei Kawauchi and Hanae Nodono and Yukako Hirao and Osamu Nishimura and Haruka Nakagawa and Kiyono Sekii and Kenta Tasaka and Hiroshi Tarui and Kiyokazu Agata and Hoshi, Motonori and Kobayashi, Kazuya and Yasubumi Sakakibara and Matsumoto, Midori} } @article {springerlink:10.1007/s00412-008-0148-6, title = {Production of diploid and triploid offspring by inbreeding of the triploid planarian Dugesia ryukyuensis}, journal = {Chromosoma}, volume = {117}, year = {2008}, note = {10.1007/s00412-008-0148-6}, pages = {289-296}, publisher = {Springer Berlin / Heidelberg}, abstract = {

Triploidy has generally been considered to be an evolutionary dead end due to problems of chromosomal pairing and segregation during meiosis. Thus, the formation of tetraploids and diploids from triploid types is a rare phenomenon. In the present study, we demonstrated that inbreeding of the triploid planarian Dugesia ryukyuensis resulted in both diploid and triploid offspring in nature. In the triploids of D. ryukyuensis , chiasmata between homologous chromosomes were observed in both female and male germ lines. This result suggests that both diploid and triploid offspring of this species are produced bisexually by zygotic fusion between sperm and eggs. Hence, this phenomenon may be a novel mechanism in planarian for escaping the triploid state.

}, issn = {0009-5915}, url = {http://dx.doi.org/10.1007/s00412-008-0148-6}, author = {Kobayashi, Kazuya and Ishizu, Hirotsugu and Arioka, Sachiko and Padilla Cabrera, Jocelyn and Hoshi, Motonori and Matsumoto, Midori} }