title: In vitro differentiation of fertile sperm from cryopreserved spermatogonia of the endangered endemic cyprinid honmoroko (Gnathopogon caerulescens).
abstract: Many endemic fish species are threatened with extinction. Conservation strategies and the restoration of endemic fish after extinction must therefore be investigated. Although sperm cryopreservation is indispensable for the conservation of endangered fishes, the limited number of mature fish and limited availability (volume and period) of sperm from small endemic fish hinders the optimization and practical use of this material. In this report, we demonstrate the in vitro differentiation of fertile sperm from cryopreserved spermatogonia of juveniles of the endangered small cyprinid honmoroko (Gnathopogon caerulescens), which is endemic to Lake Biwa in Japan. The entire process of spermatogenesis was recapitulated in vitro using cryopreserved spermatogonia of non-spawning adult and juvenile fish. The differentiation of sperm from spermatogonia was captured as a time-lapse video and confirmed by 5-ethynyl-2'-deoxyuridine (EdU) incorporation into sperm. Fertility was demonstrated by artificial insemination. These results suggest that the combination of cryopreservation of spermatogonia and in vitro sperm differentiation will provide a new and promising strategy for the preservation of paternal genetic materials.
authors.affiliation: Laboratory of Cell Engineering, Department of Pharmaceutical Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan.
authors.forename: Shogo
authors.initials: S
authors.lastname: Higaki
authors.affiliation: Laboratory of Cell Engineering, Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan.
authors.forename: Manami
authors.initials: M
authors.lastname: Shimada
authors.affiliation: Laboratory of Cell Engineering, Department of Pharmaceutical Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan.
authors.forename: Kazuaki
authors.initials: K
authors.lastname: Kawamoto
authors.affiliation: Laboratory of Cell Engineering, Department of Pharmaceutical Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan.
authors.forename: Takaaki
authors.initials: T
authors.lastname: Todo
authors.affiliation: Genetic Strains Research Center, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Kawasaki
authors.affiliation: Molecular Neuroscience Research Center, Shiga University of Medical Science, Otsu, Shiga, 520-2192, Japan.
authors.forename: Ikuo
authors.initials: I
authors.lastname: Tooyama
authors.affiliation: Lake Biwa Museum, Oroshimo 1091, Kusatsu, Shiga 525-0001, Japan.
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Fujioka
authors.affiliation: Genetic Strains Research Center, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan.
authors.forename: Noriyoshi
authors.initials: N
authors.lastname: Sakai
authors.affiliation: Laboratory of Cell Engineering, Department of Pharmaceutical Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan.|Laboratory of Cell Engineering, Graduate School of Life Sciences, Ritsumeikan University, Kusatsu, Shiga 525-8577, Japan.
authors.forename: Tatsuyuki
authors.initials: T
authors.lastname: Takada
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D003247:Conservation of Natural Resources / Q000379:methods*; D015925:Cryopreservation; D003530:Cyprinidae / Q000502:physiology*; D003857:Deoxyuridine / Q000031:analogs & derivatives / Q000378:metabolism; D056727:Endangered Species; D005260:Female; D005298:Fertility; D066298:In Vitro Techniques; D007564:Japan; D008297:Male; D013093:Spermatogonia / Q000166:cytology* / Q000378:metabolism; D013094:Spermatozoa / Q000166:cytology* / Q000378:metabolism; D059008:Time-Lapse Imaging
chemical_list: C031086:5-ethynyl-2'-deoxyuridine; D003857:Deoxyuridine