The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Sakae Kikuyama - One of the best experts on this subject based on the ideXlab platform.
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Imorin: a sexual attractiveness pheromone in female red-bellied newts (Cynops Pyrrhogaster).
Scientific Reports, 2017Co-Authors: Tomoaki Nakada, Fumiyo Toyoda, Itaru Hasunuma, Kazutoshi Yamamoto, Kouhei Matsuda, Takashi Nakakura, Satomi Onoue, Makoto Yokosuka, Sakae KikuyamaAbstract:The male red-bellied newt (Cynops Pyrrhogaster) approaches the female’s cloaca prior to performing any courtship behaviour, as if he is using some released substance to gauge whether she is sexually receptive. Therefore, we investigated whether such a female sexual attractiveness pheromone exists. We found that a tripeptide with amino acid sequence Ala-Glu-Phe is secreted by the ciliary cells in the epithelium of the proximal portion of the oviduct of sexually developed newts and confirmed that this is the major active substance in water in which sexually developed female newts have been kept. This substance only attracted sexually developed male newts and acted by stimulating the vomeronasal epithelial cells. This is the first female sexual attractiveness peptide pheromone to be identified in a vertebrate.
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possible hormonal interaction for eliciting courtship behavior in the male newt Cynops Pyrrhogaster
General and Comparative Endocrinology, 2015Co-Authors: Fumiyo Toyoda, Sakae Kikuyama, Kazuyoshi Tsutsui, Tomoaki Nakada, Itaru Hasunuma, Shogo HaraguchiAbstract:Reproductive behavior in amphibians, as in other vertebrate animals, is under the control of multiple hormonal substances. Prolactin (PRL), arginine vasotocin (AVT), androgen, and 7α-hydroxypregnenolone (7α-OH PREG), four such substances with hormonal activity, are known to be involved in the expression of the tail vibration behavior which is the initial step of courtship performed by the male newt, Cynops Pyrrhogaster. As current information on the interaction(s) between these hormones in terms of eliciting tail vibration behavior is limited, we have investigated whether the decline of expression of tail vibration behavior due to suppression of the activity of any one of these hormones can be restored by supplying any one of the other three hormones exogenously. Expression of the behavior was determined in terms of incidence (% of test animals exhibiting the behavior) and frequency (number of times that the behavior was repeated during the test period). Neither PRL nor androgen restored the decline in the incidence and frequency of the tail vibration behavior caused by the suppression of the activity of any one of other three hormones. AVT completely restored both the anti-PRL antibody-induced and flutamide (an androgen receptor antagonist)-induced, but not ketoconazole (an inhibitor of the steroidogenic CYP enzymes)-induced decline in the incidence and frequency of the tail vibration behavior. The neurosteroid, 7α-OH PREG, failed to restore flutamide-induced decline in the incidence and frequency of the behavior. However, it was able to restore both anti-PRL antibody-induced and AVT receptor antagonist-induced decline in the incidence, but not in the frequency of the behavior. In another experiment designed to see the activity of hormones enhancing the frequency of the tail vibration behavior, AVT was revealed to be more potent than 7α-OH PREG. The role of each hormonal substance in determining the expression of the tail vibration behavior was discussed based on the results.
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expression of g proteins in the olfactory receptor neurons of the newt Cynops Pyrrhogaster their unique projection into the olfactory bulbs
The Journal of Comparative Neurology, 2014Co-Authors: Tomoaki Nakada, Fumiyo Toyoda, Itaru Hasunuma, Takashi Nakakura, Makoto Yokosuka, Toru R Saito, Kimiko Haginoyamagishi, Koki Nakanishi, Sakae KikuyamaAbstract:We analyzed the expression of G protein α subunits and the axonal projection into the brain in the olfactory system of the semiaquatic newt Cynops Pyrrhogaster by immunostaining with antibodies against Gαolf and Gαo, by in situ hybridization using probes for Gαolf, Gαo, and Gαi2, and by neuronal tracing with DiI and DiA. The main olfactory epithelium (OE) consists of two parts, the ventral OE and dorsal OE. In the ventral OE, the Gαolf- and Gαo-expressing neurons are located in the apical and basal zone of the OE, respectively. This zonal expression was similar to that of the OE in the middle cavity of the fully aquatic toad Xenopus laevis. However, the Gαolf- and Gαo-expressing neurons in the newt ventral OE project their axons toward the main olfactory bulb (MOB) and the accessory olfactory bulb (AOB), respectively, whereas in Xenopus, the axons of both neurons project solely toward the MOB. In the dorsal OE of the newt, as in the principal cavity of Xenopus, the majority of the neurons express Gαolf and extend their axons into the MOB. In the vomeronasal organ (VNO), the neurons mostly express Gαo. These neurons and quite a few Gαolf-expressing neurons project their axons toward the AOB. This feature is similar to that in the terrestrial toad Bufo japonicus and is different from that in Xenopus, in which VNO neurons express solely Gαo, although their axons invariably project toward the AOB. We discuss the findings in the light of diversification and evolution of the vertebrate olfactory system. J. Comp. Neurol. 522:3501–3519, 2014. © 2014 Wiley Periodicals, Inc.
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expression of g proteins in the olfactory receptor neurons of the newt Cynops Pyrrhogaster their unique projection into the olfactory bulbs
The Journal of Comparative Neurology, 2014Co-Authors: Tomoaki Nakada, Fumiyo Toyoda, Itaru Hasunuma, Takashi Nakakura, Makoto Yokosuka, Toru R Saito, Kimiko Haginoyamagishi, Koki Nakanishi, Sakae KikuyamaAbstract:We analyzed the expression of G protein α subunits and the axonal projection into the brain in the olfactory system of the semiaquatic newt Cynops Pyrrhogaster by immunostaining with antibodies against Gαolf and Gαo , by in situ hybridization using probes for Gαolf , Gαo , and Gαi2 , and by neuronal tracing with DiI and DiA. The main olfactory epithelium (OE) consists of two parts, the ventral OE and dorsal OE. In the ventral OE, the Gαolf - and Gαo -expressing neurons are located in the apical and basal zone of the OE, respectively. This zonal expression was similar to that of the OE in the middle cavity of the fully aquatic toad Xenopus laevis. However, the Gαolf - and Gαo -expressing neurons in the newt ventral OE project their axons toward the main olfactory bulb (MOB) and the accessory olfactory bulb (AOB), respectively, whereas in Xenopus, the axons of both neurons project solely toward the MOB. In the dorsal OE of the newt, as in the principal cavity of Xenopus, the majority of the neurons express Gαolf and extend their axons into the MOB. In the vomeronasal organ (VNO), the neurons mostly express Gαo . These neurons and quite a few Gαolf -expressing neurons project their axons toward the AOB. This feature is similar to that in the terrestrial toad Bufo japonicus and is different from that in Xenopus, in which VNO neurons express solely Gαo , although their axons invariably project toward the AOB. We discuss the findings in the light of diversification and evolution of the vertebrate olfactory system.
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involvement of the neurosteroid 7α hydroxypregnenolone in the courtship behavior of the male newt Cynops Pyrrhogaster
Hormones and Behavior, 2012Co-Authors: Fumiyo Toyoda, Sakae Kikuyama, Kazuyoshi Tsutsui, Tomoaki Nakada, Itaru Hasunuma, Shogo HaraguchiAbstract:Reproductive behavior in amphibians, as in other vertebrate animals, is controlled by multiple hormones. A neurosteroid, 7α-hydroxypregnenolone, has recently been found to enhance locomotor activity in the male newt, Cynops Pyrrhogaster. Here, we show that this neurosteroid is also involved in enhancing the expression of courtship behavior. Intracerebroventricular (ICV) injection of 7α-hydroxypregnenolone enhanced courtship behavior dose-dependently in the sexually undeveloped males that had been pretreated with prolactin and gonadotropin, which is known to bring the males to a sexually developed state. But, unlike the case in the locomotion activity, 7α-hydroxypregnenolone did not elicit the behavior in males receiving no prior injections of these hormones. ICV administration of ketoconazole, an inhibitor of the steroidogenic enzyme cytochrome P450s, suppressed the spontaneously occurring courtship behavior in sexually active males. Supplementation with 7α-hydroxypregnenolone reversed the effect of ketoconazole in these animals. It was also demonstrated that the effect of the neurosteroid on the courtship behavior was blocked by a dopamine D2-like, but not by a D1-like, receptor antagonist. These results indicate that endogenous 7α-hydroxypregnenolone enhances the expression of the male courtship behavior through a dopaminergic system mediated by a D2-like receptor in the brain.
Fumiyo Toyoda - One of the best experts on this subject based on the ideXlab platform.
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Imorin: a sexual attractiveness pheromone in female red-bellied newts (Cynops Pyrrhogaster).
Scientific Reports, 2017Co-Authors: Tomoaki Nakada, Fumiyo Toyoda, Itaru Hasunuma, Kazutoshi Yamamoto, Kouhei Matsuda, Takashi Nakakura, Satomi Onoue, Makoto Yokosuka, Sakae KikuyamaAbstract:The male red-bellied newt (Cynops Pyrrhogaster) approaches the female’s cloaca prior to performing any courtship behaviour, as if he is using some released substance to gauge whether she is sexually receptive. Therefore, we investigated whether such a female sexual attractiveness pheromone exists. We found that a tripeptide with amino acid sequence Ala-Glu-Phe is secreted by the ciliary cells in the epithelium of the proximal portion of the oviduct of sexually developed newts and confirmed that this is the major active substance in water in which sexually developed female newts have been kept. This substance only attracted sexually developed male newts and acted by stimulating the vomeronasal epithelial cells. This is the first female sexual attractiveness peptide pheromone to be identified in a vertebrate.
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possible hormonal interaction for eliciting courtship behavior in the male newt Cynops Pyrrhogaster
General and Comparative Endocrinology, 2015Co-Authors: Fumiyo Toyoda, Sakae Kikuyama, Kazuyoshi Tsutsui, Tomoaki Nakada, Itaru Hasunuma, Shogo HaraguchiAbstract:Reproductive behavior in amphibians, as in other vertebrate animals, is under the control of multiple hormonal substances. Prolactin (PRL), arginine vasotocin (AVT), androgen, and 7α-hydroxypregnenolone (7α-OH PREG), four such substances with hormonal activity, are known to be involved in the expression of the tail vibration behavior which is the initial step of courtship performed by the male newt, Cynops Pyrrhogaster. As current information on the interaction(s) between these hormones in terms of eliciting tail vibration behavior is limited, we have investigated whether the decline of expression of tail vibration behavior due to suppression of the activity of any one of these hormones can be restored by supplying any one of the other three hormones exogenously. Expression of the behavior was determined in terms of incidence (% of test animals exhibiting the behavior) and frequency (number of times that the behavior was repeated during the test period). Neither PRL nor androgen restored the decline in the incidence and frequency of the tail vibration behavior caused by the suppression of the activity of any one of other three hormones. AVT completely restored both the anti-PRL antibody-induced and flutamide (an androgen receptor antagonist)-induced, but not ketoconazole (an inhibitor of the steroidogenic CYP enzymes)-induced decline in the incidence and frequency of the tail vibration behavior. The neurosteroid, 7α-OH PREG, failed to restore flutamide-induced decline in the incidence and frequency of the behavior. However, it was able to restore both anti-PRL antibody-induced and AVT receptor antagonist-induced decline in the incidence, but not in the frequency of the behavior. In another experiment designed to see the activity of hormones enhancing the frequency of the tail vibration behavior, AVT was revealed to be more potent than 7α-OH PREG. The role of each hormonal substance in determining the expression of the tail vibration behavior was discussed based on the results.
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expression of g proteins in the olfactory receptor neurons of the newt Cynops Pyrrhogaster their unique projection into the olfactory bulbs
The Journal of Comparative Neurology, 2014Co-Authors: Tomoaki Nakada, Fumiyo Toyoda, Itaru Hasunuma, Takashi Nakakura, Makoto Yokosuka, Toru R Saito, Kimiko Haginoyamagishi, Koki Nakanishi, Sakae KikuyamaAbstract:We analyzed the expression of G protein α subunits and the axonal projection into the brain in the olfactory system of the semiaquatic newt Cynops Pyrrhogaster by immunostaining with antibodies against Gαolf and Gαo, by in situ hybridization using probes for Gαolf, Gαo, and Gαi2, and by neuronal tracing with DiI and DiA. The main olfactory epithelium (OE) consists of two parts, the ventral OE and dorsal OE. In the ventral OE, the Gαolf- and Gαo-expressing neurons are located in the apical and basal zone of the OE, respectively. This zonal expression was similar to that of the OE in the middle cavity of the fully aquatic toad Xenopus laevis. However, the Gαolf- and Gαo-expressing neurons in the newt ventral OE project their axons toward the main olfactory bulb (MOB) and the accessory olfactory bulb (AOB), respectively, whereas in Xenopus, the axons of both neurons project solely toward the MOB. In the dorsal OE of the newt, as in the principal cavity of Xenopus, the majority of the neurons express Gαolf and extend their axons into the MOB. In the vomeronasal organ (VNO), the neurons mostly express Gαo. These neurons and quite a few Gαolf-expressing neurons project their axons toward the AOB. This feature is similar to that in the terrestrial toad Bufo japonicus and is different from that in Xenopus, in which VNO neurons express solely Gαo, although their axons invariably project toward the AOB. We discuss the findings in the light of diversification and evolution of the vertebrate olfactory system. J. Comp. Neurol. 522:3501–3519, 2014. © 2014 Wiley Periodicals, Inc.
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expression of g proteins in the olfactory receptor neurons of the newt Cynops Pyrrhogaster their unique projection into the olfactory bulbs
The Journal of Comparative Neurology, 2014Co-Authors: Tomoaki Nakada, Fumiyo Toyoda, Itaru Hasunuma, Takashi Nakakura, Makoto Yokosuka, Toru R Saito, Kimiko Haginoyamagishi, Koki Nakanishi, Sakae KikuyamaAbstract:We analyzed the expression of G protein α subunits and the axonal projection into the brain in the olfactory system of the semiaquatic newt Cynops Pyrrhogaster by immunostaining with antibodies against Gαolf and Gαo , by in situ hybridization using probes for Gαolf , Gαo , and Gαi2 , and by neuronal tracing with DiI and DiA. The main olfactory epithelium (OE) consists of two parts, the ventral OE and dorsal OE. In the ventral OE, the Gαolf - and Gαo -expressing neurons are located in the apical and basal zone of the OE, respectively. This zonal expression was similar to that of the OE in the middle cavity of the fully aquatic toad Xenopus laevis. However, the Gαolf - and Gαo -expressing neurons in the newt ventral OE project their axons toward the main olfactory bulb (MOB) and the accessory olfactory bulb (AOB), respectively, whereas in Xenopus, the axons of both neurons project solely toward the MOB. In the dorsal OE of the newt, as in the principal cavity of Xenopus, the majority of the neurons express Gαolf and extend their axons into the MOB. In the vomeronasal organ (VNO), the neurons mostly express Gαo . These neurons and quite a few Gαolf -expressing neurons project their axons toward the AOB. This feature is similar to that in the terrestrial toad Bufo japonicus and is different from that in Xenopus, in which VNO neurons express solely Gαo , although their axons invariably project toward the AOB. We discuss the findings in the light of diversification and evolution of the vertebrate olfactory system.
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involvement of the neurosteroid 7α hydroxypregnenolone in the courtship behavior of the male newt Cynops Pyrrhogaster
Hormones and Behavior, 2012Co-Authors: Fumiyo Toyoda, Sakae Kikuyama, Kazuyoshi Tsutsui, Tomoaki Nakada, Itaru Hasunuma, Shogo HaraguchiAbstract:Reproductive behavior in amphibians, as in other vertebrate animals, is controlled by multiple hormones. A neurosteroid, 7α-hydroxypregnenolone, has recently been found to enhance locomotor activity in the male newt, Cynops Pyrrhogaster. Here, we show that this neurosteroid is also involved in enhancing the expression of courtship behavior. Intracerebroventricular (ICV) injection of 7α-hydroxypregnenolone enhanced courtship behavior dose-dependently in the sexually undeveloped males that had been pretreated with prolactin and gonadotropin, which is known to bring the males to a sexually developed state. But, unlike the case in the locomotion activity, 7α-hydroxypregnenolone did not elicit the behavior in males receiving no prior injections of these hormones. ICV administration of ketoconazole, an inhibitor of the steroidogenic enzyme cytochrome P450s, suppressed the spontaneously occurring courtship behavior in sexually active males. Supplementation with 7α-hydroxypregnenolone reversed the effect of ketoconazole in these animals. It was also demonstrated that the effect of the neurosteroid on the courtship behavior was blocked by a dopamine D2-like, but not by a D1-like, receptor antagonist. These results indicate that endogenous 7α-hydroxypregnenolone enhances the expression of the male courtship behavior through a dopaminergic system mediated by a D2-like receptor in the brain.
Akihiko Watanabe - One of the best experts on this subject based on the ideXlab platform.
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sperm storage influences the potential for spontaneous acrosome reaction of the sperm in the newt Cynops Pyrrhogaster
Molecular Reproduction and Development, 2017Co-Authors: Shinnosuke Kon, Fubito Toyama, Tae Sato, Daisuke Endo, Tomoe Takahashi, Akio Takaku, Yuni Nakauchi, V B Meyerrochow, Eriko Takayamawatanabe, Akihiko WatanabeAbstract:Sperm storage is supposed to influence sperm quality, although the details remain unclear. In the present study, we found that sperm stored in a sperm storage site, the vas deferens of Cynops Pyrrhogaster, spontaneously undergo acrosome reaction following incubation in Steinberg's salt solution (ST). Percentages of acrosome-reacted sperm increased time-dependently to about 60% in 24 hr. The concentration of cyclic adenosine monophosphate (cAMP) was elevated after incubating sperm in ST, while dibutylyl cAMP induced an acrosome reaction. Chelating of extracellular Ca2+ suppressed the dibutylyl cAMP-induced acrosome reaction as well as spontaneous acrosome reaction in ST. These results suggest that cAMP elevation driven by Ca2+ influx can be a cue for spontaneous acrosome reaction. Relatively low Ca2+ concentration and pH in the vas deferens were sufficient to suppress spontaneous acrosome reaction within 1 hr. In addition, the cysteine rich secretory protein 2 gene was expressed in the vas deferens, indicating that it may be involved in the continuous suppression of spontaneous acrosome reaction. Sperm that underwent spontaneous acrosome reaction in ST was significantly increased when stored in the vas deferens for longer periods, or by males experiencing temperatures in excess of 12°C during hibernation conditions. Percentages of the spontaneously acrosome-reacted sperm were found to differ among males even though they were of identical genetic background. Taken together, C. Pyrrhogaster sperm possess the potential for spontaneous acrosome reaction that does not become obvious in the vas deferens, unless promoted in correlation with sperm storage.
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contribution of different ca 2 channels to the acrosome reaction mediated initiation of sperm motility in the newt Cynops Pyrrhogaster
Zygote, 2015Co-Authors: Eriko Takayamawatanabe, Hiroto Ochiai, Shunpei Tanino, Akihiko WatanabeAbstract:Initiation of sperm motility in urodeles, which is induced by a sperm motility-initiating substance (SMIS) in the sequestered granules on the surface of egg jelly, is mediated by the acrosome reaction (AR), which is triggered by an AR-inducing substance (ARIS) on a sheet-like structure. Details of the unique process of the interaction between egg jelly and sperm in these species is still unclear. The current study showed the fine structure of egg jelly in the newt Cynops Pyrrhogaster, a urodele species, revealing that its outer surface was covered by a sheet-like structure of approximately 0.29 μm in thickness. Granules of approximately 2 μm in diameter with small particles of approximately 54 nm were attached to its surface and distributed inhomogeneously just beneath the sheet-like structure. Emission spectrometry revealed that the Ca2+ concentration was maintained at a high level compared with that of the blood plasma and the vas deferens fluid, suggesting that egg jelly is a reliable source of Ca2+ for the sperm-egg interaction. Blockers of the T-type voltage-dependent Ca2+ channel (VDCC), but not the L-type VDCC, inhibited both AR and initiation of sperm motility. Conversely, Ni+, which affects the α1 H subunit of T-type VDCC, only inhibited the initiation of sperm motility. These data suggest that, in response to ARIS and SMIS, sequential gating of distinct Ca2+ channels occurs in the AR, followed by the initiation of sperm motility on the surface of the egg jelly in C. Pyrrhogaster at fertilization.
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sperm proteases that may be involved in the initiation of sperm motility in the newt Cynops Pyrrhogaster
International Journal of Molecular Sciences, 2014Co-Authors: Misato Yokoe, Eriko Takayamawatanabe, Makoto Sano, Honami Shibata, Daisuke Shibata, Kazuo Inaba, Akihiko WatanabeAbstract:A protease of sperm in the newt Cynops Pyrrhogaster that is released after the acrosome reaction (AR) is proposed to lyse the sheet structure on the outer surface of egg jelly and release sperm motility-initiating substance (SMIS). Here, we found that protease activity in the sperm head was potent to widely digest substrates beneath the sperm. The protease activity measured by fluorescein thiocarbamoyl-casein digestion was detected in the supernatant of the sperm after the AR and the activity was inhibited by 4-(2-aminoethyl) benzenesulfonyl fluoride (AEBSF), an inhibitor for serine or cysteine protease, suggesting the release of serine and/or cysteine proteases by AR. In an in silico analysis of the testes, acrosins and 20S proteasome were identified as possible candidates of the acrosomal proteases. We also detected another AEBSF-sensitive protease activity on the sperm surface. Fluorescence staining with AlexaFluor 488-labeled AEBSF revealed a cysteine protease in the principal piece; it is localized in the joint region between the axial rod and undulating membrane, which includes an axoneme and produces powerful undulation of the membrane for forward sperm motility. These results indicate that AEBSF-sensitive proteases in the acrosome and principal piece may participate in the initiation of sperm motility on the surface of egg jelly.
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in silico identification of the genes for sperm egg interaction in the internal fertilization of the newt Cynops Pyrrhogaster
The International Journal of Developmental Biology, 2014Co-Authors: Akihiko Watanabe, Eriko TakayamawatanabeAbstract:A specific sperm-egg interaction in the oviductal matrix is crucial for internal fertilization of the red-bellied newt, Cynops Pyrrhogaster. An understanding of the molecular basis of this interaction is expected to elucidate the evolutionary history of internal fertilization in amphibians. Recently, deep sequencing technology has provided global gene information even in nonmodel animals, allowing us to understand specific features of the molecular mechanisms underlying fertilization in C. Pyrrhogaster. In the present study, we screened de novo assembled RNAseq from ovary, testis, and oviduct samples in C. Pyrrhogaster and identified the base sequences encoding zona pellucida (ZP) proteins, voltage-dependent Ca2+ channels, and cysteine-rich secretory proteins (CRISPs), which respectively are sperm receptors for egg envelopes, major mediators of sperm intracellular signaling, and expected extracellular modulators for sperm function in the female reproductive tract. In the ovary, ZP homologues of all six subgroups were found, including a ZP1 homologue that was newly found in amphibians, a ZP4 homologue, and six ZPC homologues. The unique combination of ZP proteins suggests a new mechanism for sperm binding to egg envelopes in the internal fertilization of C. Pyrrhogaster. In the testis, CaV1.1, 1.2, and 3.2, which are L- and T-type voltage-dependent Ca2+ channels, were found as potential mediators for the internal fertilization-specific sperm-egg interaction. We also found CRISP 2 in the oviduct, which is speculated to participate in the sperm-egg interaction. These results indicate that the de novo assembled RNAseq is a powerful tool allowing analysis of the specific sperm-egg interactions in C. Pyrrhogaster.
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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
Development Growth & Differentiation, 2013Co-Authors: Tomoe Takahashi, Eriko Takayamawatanabe, Kazuo Inaba, Megumi Kutsuzawa, Kogiku Shiba, Akihiko WatanabeAbstract:Activation state of sperm motility named “hyperactivation” enables mammalian sperm to progress through the oviductal matrix, although a similar state of sperm motility is unknown in non-mammalian vertebrates at fertilization. Here, we found a high motility state of the sperm in the newt Cynops Pyrrhogaster. It was predominantly caused in egg jelly extract (JE) and characterized by a high wave velocity of the undulating membrane (UM) that was significantly higher at the posterior midpiece. An insemination assay suggested that the high motility state might be needed for sperm to penetrate the egg jelly, which is the accumulated oviductal matrix. Specific characteristics of the high motility state were completely abrogated by a high concentration of verapamil, which blocks the L-type and T-type voltage-dependent Ca2+ channels (VDCCs). Mibefradil, a dominant blocker of T-type VDCCs, suppressed the wave of the UM at the posterior midpiece with separate wave propagation from both the anterior midpiece and the posterior principal piece. In addition, nitrendipine, a dominant L-type VDCC blocker, weakened the wave of the UM, especially in the anterior midpiece. Live Ca2+ imaging showed that, compared with the intact sperm in the JE, the relative intracellular Ca2+ level changed especially in the anterior and posterior ends of the midpiece of the blocker-treated sperm. These suggest that different types of Ca2+ channels mediate the intracellular Ca2+ level predominantly in the anterior and posterior ends of the midpiece to maintain the high motility state of the newt sperm.
Chikafumi Chiba - One of the best experts on this subject based on the ideXlab platform.
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Dietary administration of tetrodotoxin and its putative biosynthetic intermediates to the captive-reared non-toxic Japanese fire-bellied newt, Cynops Pyrrhogaster.
Toxicon, 2017Co-Authors: Yuta Kudo, Chikafumi Chiba, Keiichi Konoki, Yuko Cho, Mari Yotsu-yamashitaAbstract:The origin of tetrodotoxin (TTX) in amphibians has long been disputed. In this study, TTX and its putative biosynthetic intermediates or shunt compounds (4,9-anhydro-10-hemiketal-5-deoxyTTX and Cep-242) were dietary administered to the captive-reared, non-toxic Japanese fire-bellied newt, Cynops Pyrrhogaster. After 4 weeks, the ingested compounds were detected mainly in the newt body using liquid chromatography-mass spectrometry (LC-MS), while these compounds were not converted into other TTX analogues in newts.
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A Transcriptome for the Study of Early Processes of Retinal Regeneration in the Adult Newt, Cynops Pyrrhogaster
2016Co-Authors: Kenta Nakamura, Hirofumi Yasumuro, Fubito Toyama, Wataru Inami, Md. Rafiqul Islam, Miyako Takayanagi, Ailidana Kunahong, Roman M. Casco-robles, Chikafumi ChibaAbstract:Retinal regeneration in the adult newt is a useful system to uncover essential mechanisms underlying the regeneration of body parts of this animal as well as to find clues to treat retinal disorders such as proliferative vitreoretinopathy. Here, to facilitate the study of early processes of retinal regeneration, we provide a de novo assembly transcriptome and inferred proteome of the Japanese fire bellied newt (Cynops Pyrrhogaster), which was obtained from eyeball samples of day 0–14 after surgical removal of the lens and neural retina. This transcriptome (237,120 in silico transcripts) contains most information of cDNAs/ESTs which has been reported in newts (C. Pyrrhogaster, Pleurodeles waltl and Notophthalmus viridescence) thus far. On the other hand, de novo assembly transcriptomes reported lately for N. viridescence only covered 16–31 % of this transcriptome, suggesting that most constituents of this transcriptome are specific to the regenerating eye tissues of C. Pyrrhogaster. A total of 87,102 in silico transcripts of this transcriptome were functionally annotated. Coding sequence prediction in combination with functional annotation revealed that 76,968 in silico transcripts encode protein/ peptides recorded in public databases so far, whereas 17,316 might be unique. qPCR and Sanger sequencing demonstrated that this transcriptome contains much information pertaining to genes that are regulated in association with cell reprogramming, cell-cycle re-entry/proliferation, and tissue patterning in an early phase of retinal regeneration. This data also provides important insight for further investigations addressing cellular mechanisms and molecular network
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ORIGINAL PAPER The newt (Cynops Pyrrhogaster) RPE65 promoter: molecular cloning, characterization and functional analysis
2016Co-Authors: Martin Miguel, Casco-robles Tomoya Miura, Chikafumi ChibaAbstract:Abstract The adult newt has the ability to regener-ate the neural retina following injury, a process achieved primarily by the retinal pigment epithelium (RPE). To deliver exogenous genes to the RPE for genetic manipulation of regenerative events, we isolated the newt RPE65 promoter region by genome walking. First, we cloned the 2.8 kb RPE65 promoter from the newt, Cynops Pyrrhogaster. Sequence ana-lysis revealed several conserved regulatory elements described previously in mouse and human RPE65 promoters. Second, having previously established an I-SceI-mediated transgenic protocol for the newt, we used it here to examine the-657 bp proximal promoter of RPE65. The promoter assay used with F0 transgenic newts confirmed transgene expression of mCherry fluorescent protein in the RPE. Using bioinformatic tools and the TRANSFAC database, we identified a 340 bp CpG island located between-635 and-296 bp in the promoter; this region contains response elements for the microphthalmia-associated transcription factor known as MITF (CACGTG, CATGTG), and E-boxes (CANNTG). Sex-determin-ing region box 9 (or SOX9) response element previ-ously reported in the regulation of RPE genes (including RPE65) was also identified in the newt RPE65 promoter. Third, we identified DNA motif boxes in the newt RPE65 promoter that are conserved among other vertebrates. The newt RPE65 promoter is an invaluable tool for site-specific delivery of exog-enous genes or genetic manipulation systems for the study of retinal regeneration in this animal
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confirmation of the absence of tetrodotoxin and its analogues in the juveniles of the japanese fire bellied newt Cynops Pyrrhogaster captive reared from eggs in the laboratory using hilic lc ms
Toxicon, 2015Co-Authors: Yuta Kudo, Chikafumi Chiba, Keiichi Konoki, Yuko Cho, Mari YotsuyamashitaAbstract:The tetrodotoxin (TTX) contents of the Japanese fire-bellied newt, Cynops Pyrrhogaster, captive-reared from eggs to metamorphosed juveniles with a non-toxic diet for 70 weeks, as well as wild-caught juvenile newts, were investigated using a high-resolution hydrophilic interaction chromatography-LC-MS. TTX was detected in 0- to 22-week-old captive-reared juvenile newts but was not detected (<15 ng/g) in the 36- to 70-week-old newts, while significant levels of TTX (1.3–14 μg/g) were detected in the wild-caught juveniles.
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The newt (Cynops Pyrrhogaster) RPE65 promoter: molecular cloning, characterization and functional analysis
Transgenic Research, 2015Co-Authors: Martin Miguel Casco-robles, Tomoya Miura, Chikafumi ChibaAbstract:The adult newt has the ability to regenerate the neural retina following injury, a process achieved primarily by the retinal pigment epithelium (RPE). To deliver exogenous genes to the RPE for genetic manipulation of regenerative events, we isolated the newt RPE65 promoter region by genome walking. First, we cloned the 2.8 kb RPE65 promoter from the newt, Cynops Pyrrhogaster . Sequence analysis revealed several conserved regulatory elements described previously in mouse and human RPE65 promoters. Second, having previously established an I - Sce I-mediated transgenic protocol for the newt, we used it here to examine the −657 bp proximal promoter of RPE65. The promoter assay used with F0 transgenic newts confirmed transgene expression of mCherry fluorescent protein in the RPE. Using bioinformatic tools and the TRANSFAC database, we identified a 340 bp CpG island located between −635 and −296 bp in the promoter; this region contains response elements for the microphthalmia-associated transcription factor known as MITF (CACGTG, CATGTG), and E-boxes (CANNTG). Sex-determining region box 9 (or SOX9) response element previously reported in the regulation of RPE genes (including RPE65) was also identified in the newt RPE65 promoter. Third, we identified DNA motif boxes in the newt RPE65 promoter that are conserved among other vertebrates. The newt RPE65 promoter is an invaluable tool for site-specific delivery of exogenous genes or genetic manipulation systems for the study of retinal regeneration in this animal.
Tomoaki Nakada - One of the best experts on this subject based on the ideXlab platform.
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Imorin: a sexual attractiveness pheromone in female red-bellied newts (Cynops Pyrrhogaster).
Scientific Reports, 2017Co-Authors: Tomoaki Nakada, Fumiyo Toyoda, Itaru Hasunuma, Kazutoshi Yamamoto, Kouhei Matsuda, Takashi Nakakura, Satomi Onoue, Makoto Yokosuka, Sakae KikuyamaAbstract:The male red-bellied newt (Cynops Pyrrhogaster) approaches the female’s cloaca prior to performing any courtship behaviour, as if he is using some released substance to gauge whether she is sexually receptive. Therefore, we investigated whether such a female sexual attractiveness pheromone exists. We found that a tripeptide with amino acid sequence Ala-Glu-Phe is secreted by the ciliary cells in the epithelium of the proximal portion of the oviduct of sexually developed newts and confirmed that this is the major active substance in water in which sexually developed female newts have been kept. This substance only attracted sexually developed male newts and acted by stimulating the vomeronasal epithelial cells. This is the first female sexual attractiveness peptide pheromone to be identified in a vertebrate.
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possible hormonal interaction for eliciting courtship behavior in the male newt Cynops Pyrrhogaster
General and Comparative Endocrinology, 2015Co-Authors: Fumiyo Toyoda, Sakae Kikuyama, Kazuyoshi Tsutsui, Tomoaki Nakada, Itaru Hasunuma, Shogo HaraguchiAbstract:Reproductive behavior in amphibians, as in other vertebrate animals, is under the control of multiple hormonal substances. Prolactin (PRL), arginine vasotocin (AVT), androgen, and 7α-hydroxypregnenolone (7α-OH PREG), four such substances with hormonal activity, are known to be involved in the expression of the tail vibration behavior which is the initial step of courtship performed by the male newt, Cynops Pyrrhogaster. As current information on the interaction(s) between these hormones in terms of eliciting tail vibration behavior is limited, we have investigated whether the decline of expression of tail vibration behavior due to suppression of the activity of any one of these hormones can be restored by supplying any one of the other three hormones exogenously. Expression of the behavior was determined in terms of incidence (% of test animals exhibiting the behavior) and frequency (number of times that the behavior was repeated during the test period). Neither PRL nor androgen restored the decline in the incidence and frequency of the tail vibration behavior caused by the suppression of the activity of any one of other three hormones. AVT completely restored both the anti-PRL antibody-induced and flutamide (an androgen receptor antagonist)-induced, but not ketoconazole (an inhibitor of the steroidogenic CYP enzymes)-induced decline in the incidence and frequency of the tail vibration behavior. The neurosteroid, 7α-OH PREG, failed to restore flutamide-induced decline in the incidence and frequency of the behavior. However, it was able to restore both anti-PRL antibody-induced and AVT receptor antagonist-induced decline in the incidence, but not in the frequency of the behavior. In another experiment designed to see the activity of hormones enhancing the frequency of the tail vibration behavior, AVT was revealed to be more potent than 7α-OH PREG. The role of each hormonal substance in determining the expression of the tail vibration behavior was discussed based on the results.
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expression of g proteins in the olfactory receptor neurons of the newt Cynops Pyrrhogaster their unique projection into the olfactory bulbs
The Journal of Comparative Neurology, 2014Co-Authors: Tomoaki Nakada, Fumiyo Toyoda, Itaru Hasunuma, Takashi Nakakura, Makoto Yokosuka, Toru R Saito, Kimiko Haginoyamagishi, Koki Nakanishi, Sakae KikuyamaAbstract:We analyzed the expression of G protein α subunits and the axonal projection into the brain in the olfactory system of the semiaquatic newt Cynops Pyrrhogaster by immunostaining with antibodies against Gαolf and Gαo , by in situ hybridization using probes for Gαolf , Gαo , and Gαi2 , and by neuronal tracing with DiI and DiA. The main olfactory epithelium (OE) consists of two parts, the ventral OE and dorsal OE. In the ventral OE, the Gαolf - and Gαo -expressing neurons are located in the apical and basal zone of the OE, respectively. This zonal expression was similar to that of the OE in the middle cavity of the fully aquatic toad Xenopus laevis. However, the Gαolf - and Gαo -expressing neurons in the newt ventral OE project their axons toward the main olfactory bulb (MOB) and the accessory olfactory bulb (AOB), respectively, whereas in Xenopus, the axons of both neurons project solely toward the MOB. In the dorsal OE of the newt, as in the principal cavity of Xenopus, the majority of the neurons express Gαolf and extend their axons into the MOB. In the vomeronasal organ (VNO), the neurons mostly express Gαo . These neurons and quite a few Gαolf -expressing neurons project their axons toward the AOB. This feature is similar to that in the terrestrial toad Bufo japonicus and is different from that in Xenopus, in which VNO neurons express solely Gαo , although their axons invariably project toward the AOB. We discuss the findings in the light of diversification and evolution of the vertebrate olfactory system.
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expression of g proteins in the olfactory receptor neurons of the newt Cynops Pyrrhogaster their unique projection into the olfactory bulbs
The Journal of Comparative Neurology, 2014Co-Authors: Tomoaki Nakada, Fumiyo Toyoda, Itaru Hasunuma, Takashi Nakakura, Makoto Yokosuka, Toru R Saito, Kimiko Haginoyamagishi, Koki Nakanishi, Sakae KikuyamaAbstract:We analyzed the expression of G protein α subunits and the axonal projection into the brain in the olfactory system of the semiaquatic newt Cynops Pyrrhogaster by immunostaining with antibodies against Gαolf and Gαo, by in situ hybridization using probes for Gαolf, Gαo, and Gαi2, and by neuronal tracing with DiI and DiA. The main olfactory epithelium (OE) consists of two parts, the ventral OE and dorsal OE. In the ventral OE, the Gαolf- and Gαo-expressing neurons are located in the apical and basal zone of the OE, respectively. This zonal expression was similar to that of the OE in the middle cavity of the fully aquatic toad Xenopus laevis. However, the Gαolf- and Gαo-expressing neurons in the newt ventral OE project their axons toward the main olfactory bulb (MOB) and the accessory olfactory bulb (AOB), respectively, whereas in Xenopus, the axons of both neurons project solely toward the MOB. In the dorsal OE of the newt, as in the principal cavity of Xenopus, the majority of the neurons express Gαolf and extend their axons into the MOB. In the vomeronasal organ (VNO), the neurons mostly express Gαo. These neurons and quite a few Gαolf-expressing neurons project their axons toward the AOB. This feature is similar to that in the terrestrial toad Bufo japonicus and is different from that in Xenopus, in which VNO neurons express solely Gαo, although their axons invariably project toward the AOB. We discuss the findings in the light of diversification and evolution of the vertebrate olfactory system. J. Comp. Neurol. 522:3501–3519, 2014. © 2014 Wiley Periodicals, Inc.
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involvement of the neurosteroid 7α hydroxypregnenolone in the courtship behavior of the male newt Cynops Pyrrhogaster
Hormones and Behavior, 2012Co-Authors: Fumiyo Toyoda, Sakae Kikuyama, Kazuyoshi Tsutsui, Tomoaki Nakada, Itaru Hasunuma, Shogo HaraguchiAbstract:Reproductive behavior in amphibians, as in other vertebrate animals, is controlled by multiple hormones. A neurosteroid, 7α-hydroxypregnenolone, has recently been found to enhance locomotor activity in the male newt, Cynops Pyrrhogaster. Here, we show that this neurosteroid is also involved in enhancing the expression of courtship behavior. Intracerebroventricular (ICV) injection of 7α-hydroxypregnenolone enhanced courtship behavior dose-dependently in the sexually undeveloped males that had been pretreated with prolactin and gonadotropin, which is known to bring the males to a sexually developed state. But, unlike the case in the locomotion activity, 7α-hydroxypregnenolone did not elicit the behavior in males receiving no prior injections of these hormones. ICV administration of ketoconazole, an inhibitor of the steroidogenic enzyme cytochrome P450s, suppressed the spontaneously occurring courtship behavior in sexually active males. Supplementation with 7α-hydroxypregnenolone reversed the effect of ketoconazole in these animals. It was also demonstrated that the effect of the neurosteroid on the courtship behavior was blocked by a dopamine D2-like, but not by a D1-like, receptor antagonist. These results indicate that endogenous 7α-hydroxypregnenolone enhances the expression of the male courtship behavior through a dopaminergic system mediated by a D2-like receptor in the brain.
