H. Furukawa, S. Mito, J. Nishio, N. Sato, Y. Ando, A. Tominaga, F. Toyama, Y. Nakauchi, E. Takayama-Watanabe, A. Watanabe 2023. Identification and characterization of sperm motility initiating substance-2 gene in the internally fertilizing Cynops species. Develop.Growth Differ. 65: 144-152.


T. Sato, T. Arimura, K. Murata, M. Kawamura, W. Obama, M. Suzuki, Y.  Nakauchi, A.Tominaga, M. Morita, K. Hiraoka, E. Takayama-Watanabe, A.Watanabe 2021. Differences of extracellular cues and Ca2+ permeable channels in the signaling pathways for inducing amphibian sperm motility. Zool. Sci. 38:343-351.

N. Makino, N. Sato, E. Takayama-Watanabe, A. Watanabe. 2020. Localization of sperm intracellular Ca2+ keeps fertilizability in the newt vas deferens. Reproduction 159:339-349.

S. Kon, A. Takaku, F. Toyama, E. Takayama-Watanabe, A. Watanabe. 2019. Acrosome reaction inducing substance triggers two different pathways of sperm intracellular signaling in newt fertilization. Int. J. Dev. Biol. 63: 589-595. 

D. Endo, S. Kon, T. Sato, F. Toyama, Y. Katsura, Y. Nakauchi, E. Takayama-Watanabe, A. Watanabe. 2019. NMDA-type glutamate receptors mediate the acrosome reaction and motility initiation in newt sperm. Mol. Reprod. Dev. 86: 1106-1115. doi: 10.1002/mrd.23225.

R.M. Casco-Robles, A. Watanabe, K. Eto, K. Takeshima, S. Obata, T. Kinoshita, T. Ariizumi, K. Nakatani, T. Nakada, P.A. Tsonis, M.M. Casco-Robles, K. Sakurai, K. Yahata, F. Maruo, F. Toyama, C. Chiba. 2018. Novel erythrocyte clumps revealed by an orphan gene Newtic1 in circulating blood and regenerating limbs of the adult newt. Sci. Rep. 8: 7455. doi:10.1038/s41598-018-25867-x

S. Kon, T. Sato, D. Endo, T. Takahashi, A. Takaku, Y. Nakauchi, F. Toyama, V. B. Meyer-Rochow, E. Takayama-Watanabe, A.Watanabe. 2017. Sperm storage influences the potential for spontaneous acrosome reaction of the sperm in the newt Cynops pyrrhogaster. Mol. Reprod. Dev. 84: 1314-1322. DOI: 10.1002/mrd.22932.

T. Sato, M. Yokoe, D. Endo, M. Morita, F. Toyama, Y. Kawamura, Y. Nakauchi, E. Takayama-Watanabe, A. Watanabe. 2017. Sperm motility initiating substance may be insufficient to induce forward motility of Cynops ensicauda sperm. Mol. Reprod. Dev. 84: 686-692.

M. Yokoe, E. Takayama-Watanabe, Y. Saito,  M. Kutsuzawa,  K. Fujita, H. Ochi, Y. Nakauchi, A. Watanabe. 2016. A novel cysteine knot protein for enhancing sperm motility that might facilitate the evolution of internal fertilization in amphibians. PLOS ONE 11: e0160445.

E. Takayama-Watanabe,  H. Ochiai,  S. Tanino,  A. Watanabe.  2015. Contribution of different Ca2+ channels to the acrosome reaction-mediated initiation of sperm motility in the newt Cynops pyrrhogaster. Zygote 23:  342-351.

A. Watanabe,  E. Takayama-Watanabe.  2014.  In silico identification of the genes for sperm-egg interaction in the internal fertilization of the newt Cynops pyrrhogaster. Int. J. Dev. Biol.  58: 873-879.

M. Yokoe,  M.  Sano,  H.  Shibata,  D. 
Shibata,  E.  Takayama-Watanabe,  K.  Inaba,  A.  Watanabe. 2014.  Sperm proteases that may be involved in the initiation of sperm motility in the newt, Cynops pyrrhogaster.  Int.  J.  Mol.  Sci.  15: 15210-15224.

 E. Takayama-Watanabe,  T. Takahashi,  M. Yokoe,  A. Watanabe.  2014.  Acrosome reaction-mediated motility initiation that is critical for the internal fertilization of urodele amphibians. In Sexual reproduction in animals and plants.  H.  Sawada, N.  Inoue, M.  Iwano (eds) Springer, Tokyo, Japan, pp. 97-103.

T. Takahashi,  M. Kutsuzawa,  K. Shiba,  E. Takayama-Watanabe,  K. Inaba,  A. Watanabe. 2013. Distinct Ca2+ channels maintain a high motility state of the sperm that may be needed for penetration of egg jelly of the newt, Cynops pyrrhogaster. Develop. Growth Differ.  55: 657-667.

E. Takayama-Watanabe,  C. Campanella,  H. Kubo and A.  Watanabe. 2012. Sperm motility initiation by egg jelly of the anuran, Discoglossus pictus may be mediated by sperm motility-initiating substance of the internally-fertilizing newt, Cynops pyrrhogaster. Zygote 20: 417-422.

Y. Nakauchi,  Y. Hayakawa,  M. Fujinoki,  O.Yamamura,  M. Kobayashi,  A. Watanabe. 2011. Characterization of an alternative chromatin remodeling to parasperm in a cottid fish, Hemilepidotus gilberti. Zool. Sci. 28: 438-443.

A. Watanabe,  E. Takayama-Watanabe,  C. A. Vines,  G. N. Cherr. 2011. Sperm motility-initiating substance in newt egg-jelly induces differential initiation of sperm motility based on sperm intracellular calcium levels. Develop. Growth Differ. 53: 9-17.

M. Ohta,  H. Kubo,  Y. Nakauchi  A. Watanabe. 2010. Sperm motility-initiating activity in the egg jelly of the externally-fertilizing urodele amphibian, Hynobius lichenatus. Zool. Sci. 27: 875-879.
T. Watanabe,  H. Kubo,  S. Takeshima,  M. Nakagawa,  M. Ohta,  S. Kamimura,  E. Takayama-Watanabe,  A. Watanabe,  K. Onitake. 2010. Identification of the sperm motility-initiating substance in the newt, Cynops pyrrhogaster, and its possible relation with the acrosome reaction during internal fertilization. Int. J. Dev. Biol. 54: 591-597.

Y. Iwasaki,  K. Ohkawa,  H. Sadakata,  A. Kashiwadate,  E. Takayama-Watanabe,  K. Onitake,  A. Watanabe. 2009. Two states of active spermatogenesis switch between reproductive and non-reproductive seasons in the testes of the medaka, Oryzias latipes. Develop. Growth Differ. 51: 521-532.

A. Watanabe. 2009 Spermatogenesis, In vitro spermatogenesis from primary spermatocytes. In  Medaka
Biology, Management, and Experimental Protocols. M. Kinoshita, K. Murata, M. Tanaka (Eds.).  Blackwell publishing Ltd pp. 74-75, 350-353.

A. Watanabe,  K. Fukutomi,  H. Kubo,  M. Ohta,  E. Takayama-Watanabe,  K. Onitake. 2009. Identification of egg-jelly substances triggering sperm acrosome reaction in the newt, Cynops pyrrhogaster. Mol Reprod Dev. 76: 399-406.

Y. Hayakawa,  E. Takayama-Watanabe,  A. Watanabe,  M. Kobayashi,  H. Munehara,  K. Onitake. 2007. Partial formation of sperm dimorphism from spermatocytes of the cottoid fish, Hemilepidotus gilberti in cell culture. Zygote 15: 285-293.

W. Hiyoshi,  T. Sasaki,  E. Takayama-Watanabe,  H. Takai,  A. Watanabe,  K. Onitake. 2007. Egg-jelly of the newt, Cynops pyrrhogaster contains a factor essential for sperm binding to the vitelline envelope. J. Exp. Zool. 307A: 301-311.

A. Watanabe,  K. Onitake. 2007. The Regulation of Spermatogenesis in Fish: Recent Cellular and Molecular Approaches In: "Fish Spermatology. " eds. by S.M.H. Alavi, J.J. Cosson, K. Coward, & Gh. Rafiee, Oxford, Alpha Science Ltd
 Publications, pp. 141-160.

Y. Hayakawa,  M. Kobayashi,  H. Munehara,  A. Watanabe,  K. Onitake. 2007. Spermatogenesis involving parasperm production in the marine cottoid fish, Hemilepidotus gilberti. The Raffles Bulletin of Zoology, Sup 14: 29-35.

S. Takahashi,  H. Nakazawa,  A. Watanabe,  K. Onitake,  2006. The outermost layer of egg-jelly is crucial to successful fertilization in the newt, Cynops pyrrhogaster. J. Exp. Zool. 305A: 1010-1017.

T. Sasaki,  A. Watanabe,  E. Takayama-Watanabe,  M. Suzuki,  H. Abe,  K. Onitake. 2005. Ordered progress of spermiogenesis to the fertilizable sperm of the medaka fish, Oryzias latipes, in cell culture. Develop. Growth & Differ. 47: 87-97.

A. Watanabe,  K. Onitake. 2003. Sperm activation. In "Reproductive biology and phylogeny of urodela." ed. by David M. Sever. Science publisher, Inc. Enfield (NH). USA. pp.425-445.

Y. Makabe-Kobayashi,  E. Kudaira,  A. Watanabe,  K. Onitake. 2003. Newt ZPC molecule, cpZPC, localizes in the inner surface of the egg envelope. Int. J. Dev. Biol. 47: 51-58.

T. Watanabe,  T. Itoh,  A. Watanabe,  K. Onitake. 2003. Characteristics of sperm motility induced on the egg-jelly in the internal fertilization of the newt, Cynops pyrrhogaster. Zool. Sci. 20: 345-352.

A. Watanabe,  K. Onitake. 2002. Urodela egg-coat as the apparatus for the internal fertilization. Zool. Sci. 19: 1341-1347.

T. Sasaki,  S. Kamimura,  H. Takai,  A. Watanabe,  K. Onitake. 2002. The activity for the induction of sperm acrosome reaction localises in the outer layers and exists in the high molecular weight components of egg-jelly of the newt, Cynops pyrrhogaster. Zygote 10: 1-9.

T. Itoh,  S. Kamimura,  A. Watanabe,  K. Onitake. 2002. Egg-jelly structure promotes efficiency of internal fertilization in the newt, Cynops pyrrhogaster. J. Exp. Zool. 292: 314-322.

M. Okimura,  A. Watanabe,  K. Onitake. 2001. Organization of carbohydrate components in the egg-jelly layers of the newt, Cynops pyrrhogaster. Zool. Sci. 18: 909-918.

K. Onitake,  H. Takai,  M. Ukita,  J. Mizuno,  T. Sasaki ,  A. Watanabe. 2000. Significance of egg-jelly substances in the internal fertilization of the newt, Cynops pyrrhogaster. Comp. Biochem. Physiol. 126: 121-128.

J. Mizuno,  A. Watanabe,  K. Onitake. 1999. Initiation of sperm motility in the newt, Cynops pyrrhogaster, is induced by a heat-stable component of egg-jelly. Zygote. 7: 329-334.

M. Ukita,  T. Itoh,  T. Watanabe,  A. Watanabe,  K. Onitake. 1999. Substances for the initiation of sperm motility in egg-jelly of the Japanese newt, Cynops pyrrhogaster. Zool. Sci. 16: 793-802.

S. Nakai,  A. Watanabe,  K. Onitake. 1999. Sperm surface heparin/heparan sulfate is responsible for sperm binding to the uterine envelope in the newt, Cynops pyrrhogaster. Develop. Growth & Differ. 41: 101-107.

A. Watanabe,  E. Kobayashi,  T. Ogawa,  K. Onitake. 1998. Fibroblast growth factor may regulate the initiation of oocyte growth in the developing ovary of the medaka, Oryzias latipes. Zool. Sci. 15: 531-536.

A. Saiki,  M. Tamura,  M. Matsumoto,  J. Katowgi,  A. Watanabe,  K. Onitake. 1997. Establishment of in vitro spermatogenesis from spermatocytes in the medaka Oryzias latipes. Develop. Growth & Differ. 39: 337-344.

A. Watanabe,  N. Hatakeyama,  A. Yasuoka,  K. Onitake. 1997. Distributions of fibroblast growth factor and the mRNA for its receptor, MFR1, in the developing testis of the medaka, Oryzias latipes. J. Exp. Zool. 279: 177-184.

A. Watanabe,  K. Onitake.1995. Changes in the distribution of fibroblast growth factor in the teleostean testis during spermatogenesis. J. Exp. Zool. 272: 475-483.

A. Watanabe,  H. Ide. 1993. Basic FGF maintains some characteristics of the progress zone of chick limb bud in cell culture. Dev. Biol. 159: 223-231.

A. Watanabe,  K. Ohsugi,  H. Ide. 1993. Formation of distal structures from stumps of chick wing buds at stage 24-25 following the grafting of quail tissue from X-irradiated distal limb buds. J. Exp. Zool. 267: 447-453.