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Masatoshi Mita - One of the best experts on this subject based on the ideXlab platform.
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Enzyme-linked immunosorbent assay of relaxin-like gonad-stimulating peptide in the starfish Patiria (Asterina) pectinifera.
General and comparative endocrinology, 2017Co-Authors: Masatoshi Mita, Hidekazu KatayamaAbstract:Abstract A relaxin-like gonad-stimulating peptide (RGP) from starfish Patiria (Asterina) pectinifera is the first identified invertebrate gonadotropin for final gamete maturation. Recently, we succeeded in obtaining specific antibodies against P. pectinifera RGP (PpeRGP). In this study, the antibodies were used for the development of a specific and sensitive enzyme-linked immunosorbent assay (ELISA) for the measurement of PpeRGP. A biotin-conjugated peptide that binds to peroxidase-conjugated streptavidin is specifically detectable using 3,3′,5,5′-tetramethylbenzidine (TMB)/hydrogen peroxide as a substrate; therefore, biotin-conjugated RGP (biotin-PpeRGP) was synthesized chemically. Similarly to PpeRGP, synthetic biotin-PpeRGP bound to the antibody against PpeRGP. In binding experiments with biotin-PpeRGP using wells coated with the antibody, a displacement curve was obtained using serial concentrations of PpeRGP. The ELISA system showed that PpeRGP could be measured in the range 0.01–10 pmol per 50 µl assay buffer. On the contrary, the B-chains of PpeRGP, Asterias amurensis RGP, Aphelasterias japonica RGP, and human relaxin showed minimal cross-reactivity in the ELISA, except that the A-chain of PpeRGP affected it slightly. These results strongly suggest that this ELISA system is highly specific and sensitive with respect to PpeRGP.
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Inhibitory mechanism of l-glutamic acid on spawning of the starfish Patiria (Asterina) pectinifera.
Molecular reproduction and development, 2017Co-Authors: Masatoshi MitaAbstract:SUMMARY l-Glutamic acid was previously identified as an inhibitor of spawning in the starfish Patiria (Asterina) pectinifera; this study examined how l-glutamic acid works. Oocyte release from ovaries of P. pectinifera occurred after germinal vesicle breakdown (GVBD) and follicular envelope breakdown (FEBD) when gonads were incubated ex vivo with either relaxin-like gonad-stimulating peptide (RGP) or 1-methyladenine (1-MeAde). l-Glutamic acid blocked this spawning phenotype, causing the mature oocytes to remain within the ovaries. Neither RGP-induced 1-MeAde production in ovarian follicle cells nor 1-MeAde-induced GVBD and FEBD was affected by l-glutamic acid. l-Glutamic acid may act through metabotropic receptors in the ovaries to inhibit spawning, as l-(+)-2-amino-4-phosphonobutyric acid, an agonist for metabotropic glutamate receptors, also inhibited spawning induced by 1-MeAde. Application of acetylcholine (ACH) to ovaries under inhibitory conditions with l-glutamic acid, however, brought about spawning, possibly by inducing contraction of the ovarian wall to discharge mature oocytes from the ovaries concurrently with GVBD and FEBD. Thus, l-glutamic acid may inhibit ACH secretion from gonadal nerve cells in the ovary. Mol. Reprod. Dev. 84: 246–256, 2017. © 2017 Wiley Periodicals, Inc.
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Radioimmunoassay of relaxin-like gonad-stimulating peptide in the starfish Patiria (=Asterina) pectinifera.
General and comparative endocrinology, 2016Co-Authors: Kazutoshi Yamamoto, Masato Kiyomoto, Hidekazu Katayama, Masatoshi MitaAbstract:Abstract A relaxin-like gonad-stimulating peptide (RGP) from starfish Patiria (= Asterina ) pectinifera is the first identified invertebrate gonadotropin for final gamete maturation. An antiserum against P. pectinifera RGP (PpeRGP) was produced by immunizing rabbits with a PpeRGP sulfanyl-polyethylene glycol derivative conjugated with keyhole limpet hemocyanin (KLH) as the antigen. The antiserum was used for the development of a specific and sensitive radioimmunoassay (RIA) for the measurement of RGP. In binding experiments using radioiodinated PpeRGP and antiserum against PpeRGP, a displacement curve was obtained using radioinert PpeRGP. The sensitivity of the RIA, defined as the amount of PpeRGP that significantly decreased the counts by 2 SD from the 100% bound point, averaged 0.040 ± 0.002 pmol PpeRGP per 100 μl assay buffer (0.40 ± 0.02 nM) in 10 assays. Intra-assay and inter-assay coefficients of variation were 6.1% and 2.7%, respectively. Serial dilution of whole homogenates from the radial nerve cords and circumoral nerve-rings of P. pectinifera produced displacement curves parallel to the PpeRGP standard. Thus, the amounts of PpeRGP were determined as 1.54 ± 0.09 pmol/mg wet weight of radial nerves and 0.87 ± 0.04 pmol/mg wet weight of nerve-rings, respectively. On contrary, pyloric stomach, pyloric caeca, tube-feet, ovaries, testes, and ovarian follicle cells did not react in the RIA system. Furthermore, the A- and B-chains of PpeRGP, Asterias amurensis RGP, bovine insulin, and human relaxin did not show cross-reactivity in the RIA. These results strongly suggest that the RIA system is a highly specific and sensitive with respect to PpeRGP.
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Relaxin-like gonad-stimulating peptide is highly conserved in starfish Asterina pectinifera
Invertebrate Reproduction & Development, 2015Co-Authors: Narumi Ikeda, Haruka Uzawa, Misaki Daiya, Shogo Haraguchi, Kazuyoshi Tsutsui, Masatoshi MitaAbstract:Relaxin-like gonad-stimulating peptide (RGP) in starfish is the only known invertebrate peptide hormone responsible for final gamete maturation, rendering it functionally analogous to gonadotropins in vertebrates. Recently, RGP was purified from the radial nerves of starfish Asterina pectinifera, which belongs to the Order Valvatida in the Class Asteroidea. A. pectinifera is an endemic Japanese species, inhabiting rocky shores from northern to southern Japanese waters. This study examined whether genetic variation or polymorphism is found in RGP. Comparing cDNA sequences of RGP in A. pectinifera from 10 local populations in Japanese waters, we found that the coding DNA sequences (CDSs) were exactly the same. This result indicated that RGP is a highly conserved peptide in A. pectinifera. Furthermore, the CDS of RGP identified in Certonardoa semiregularis, which also belongs to Order Valvatida, was completely consistent with that of A. pectinifera. Thus, this also suggested that the chemical structure of A....
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Nucleotide sequence and expression of relaxin-like gonad-stimulating peptide gene in starfish Asterina pectinifera.
General and comparative endocrinology, 2015Co-Authors: Shogo Haraguchi, Narumi Ikeda, Kazuyoshi Tsutsui, Michiko Abe, Masatoshi MitaAbstract:Abstract Starfish gonad-stimulating substance (GSS) is the only known invertebrate peptide hormone responsible for final gamete maturation, rendering it functionally analogous to gonadotropins in vertebrates. Because GSS belongs to the relaxin-like peptide family, we propose renaming for starfish gonadotropic hormone as relaxin-like gonad-stimulating peptide (RGP). This study examined the primary structure and expression regulation of the RGP gene in starfish Asterina pectinifera. RGP consisted of 3896 base pairs (bp) divided over two exons, exon 1 of 208 bp and exon 2 of 2277 bp, and one intron of 1411 bp. Promoter sequences, CAAT and TATA boxes, were present in the 5′-upstream region of the coding DNA sequence of RGP. The transcript was 2485 bases (b) in length. The AAUAAA polyadenylation signal was found in 3′-untranslated region over 2 kb away from the stop codon. This showed that only 14% of the RGP mRNA was translated into the peptide, because a size of the open-reading frame was 351 b. Furthermore, an analysis by using real-time quantitative PCR with specific primers for RGP showed that mRNA of RGP was expressed at high levels in the radial nerves. Expression was also observed in the cardiac stomachs, although the level was low, and trace levels were detected in the gonads, pyloric caeca and tube feet. This result suggests that the RGP gene is transcribed mainly in the radial nerves of A. pectinifera.
Hiroko Shirai - One of the best experts on this subject based on the ideXlab platform.
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Germ Cell Differentiation in Starfish: The Posterior Enterocoel as the Origin of Germ Cells in Asterina pectinifera
Development Growth and Differentiation, 1992Co-Authors: Chiemi Inoue, Masato Kiyomoto, Hiroko ShiraiAbstract:The origin of germ cells of Asterina pectinifera was traced back to the posterior enterocoel (PE) of 2-day bipinnaria by two steps. First, the cellular cluster, composed of presumptive germ cells in the coelomic epithelium at brachiolaria stage, was confirmed to be the origin of the aboral haemal sinus located near the hydroporic canal (HC-AHS) by continuous observation of the formation process of HC-AHS. Second, the origin of the cluster was traced back to the PE of 2-day bipinnaria by comparison of the number of the presumptive germ cells in microsurgically PE-removed bipinnariae with that of non-operated control larvae. A summary of the differentiation of germ cells in Asterina pectinifera is given/presented.
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Origin of Germ Cells and Early Differentiation of Gonads in the Starfish, Asterina pectinifera. (starfish/germ cells/PGC/gonad/haemal sinus)
Development Growth & Differentiation, 1991Co-Authors: Chiemi Inoue, Hiroko ShiraiAbstract:The origin of the germ cells and the development of the genital system in the annually spawning starfish, Asterina pectinifera, were studied by light and electron microscopy. Characteristic germ cells were first characterized in gonads after spawning: the gonia are larger than somatic cells, have large nuclei (with electron-lucent nucleoplasm), and show mitochondrial aggregation associated with nuage (electron-dense bodies). In young starfish without gonads similar cells were detected in the haemal sinus, where they were termed primordial germ cells (PGCs). Brachiolariae and metamorphosed juveniles had a cellular cluster in the coelomic epithelium, near the hydroporic canal. The cluster was comprised of cells endowed with the above-mentioned characteristics of the germ cells. The germ cell counts indicated that PGCs migrate from the aboral haemal sinus near the hydroporic canal, through the haemal sinus to the gonads, where they settle, proliferate, and differentiate into gonia.
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origin of germ cells and early differentiation of gonads in the starfish Asterina pectinifera starfish germ cells pgc gonad haemal sinus
Development Growth & Differentiation, 1991Co-Authors: Chiemi Inoue, Hiroko ShiraiAbstract:The origin of the germ cells and the development of the genital system in the annually spawning starfish, Asterina pectinifera, were studied by light and electron microscopy. Characteristic germ cells were first characterized in gonads after spawning: the gonia are larger than somatic cells, have large nuclei (with electron-lucent nucleoplasm), and show mitochondrial aggregation associated with nuage (electron-dense bodies). In young starfish without gonads similar cells were detected in the haemal sinus, where they were termed primordial germ cells (PGCs). Brachiolariae and metamorphosed juveniles had a cellular cluster in the coelomic epithelium, near the hydroporic canal. The cluster was comprised of cells endowed with the above-mentioned characteristics of the germ cells. The germ cell counts indicated that PGCs migrate from the aboral haemal sinus near the hydroporic canal, through the haemal sinus to the gonads, where they settle, proliferate, and differentiate into gonia.
Valentin A. Stonik - One of the best experts on this subject based on the ideXlab platform.
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LC-ESI MS/MS profiling of polar steroid metabolites of the Far Eastern starfish Patiria (=Asterina) pectinifera
Metabolomics, 2015Co-Authors: Roman S. Popov, Alla A. Kicha, Pavel S. Dmitrenok, Natalia V. Ivanchina, Timofey V. Malyarenko, Valentin A. StonikAbstract:Profiling of asterosaponins, polyhydroxysteroids and glycosides of polyhydroxysteroids of the common in the Far Eastern sea waters starfish Patiria ( = Asterina) pectinifera was performed by LC-ESI MS and LC-APPI MS. The 72 polar steroid metabolites, including 35 asterosaponins, 22 polyhydroxysteroids and 15 sulfated glycosides of polyhydroxysteroids, were detected and identified using the LC–MS and LC–MS/MS spectra. The steroid metabolome of P. pectinifera is characterized by large number of sulfated and non-sulfated highly oxidized compounds with cholestane, ergostane and stigmastane skeleton systems of aglycones. Some peculiarities of biosynthesis of the starfish polar steroids were discussed. It was suggested that biosynthesis of asterosaponins from diet sterols is executed in a mosaic type manner with transformations in aglycone moieties and elongation of carbohydrate chains proceeding independently from each other and simultaneously.
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Seasonal variations in polyhydroxysteroids and related glycosides from digestive tissues of the starfish Patiria (=Asterina) pectinifera.
Comparative biochemistry and physiology. Part B Biochemistry & molecular biology, 2004Co-Authors: Alla A. Kicha, Natalia V. Ivanchina, Valentin A. StonikAbstract:Seasonal variations in the concentrations of individual polyhydroxysteroids and related low molecular weight glycosides in pyloric caeca and stomach of the starfish Patiria (=Asterina) pectinifera collected at one location near Vladivostok have been studied. HPLC analysis on the fractions containing these substances showed a fairly constant composition of steroids in digestive tissues of P. pectinifera in spite of small seasonal variations in the relative concentrations of individual compounds.
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Seasonal variations in the levels of polyhydroxysteroids and related glycosides in the digestive tissues of the starfish Patiria (Asterina) pectinifera.
Comparative biochemistry and physiology. Part B Biochemistry & molecular biology, 2003Co-Authors: Alla A. Kicha, Natalia V. Ivanchina, Valentin A. StonikAbstract:Seasonal variations in the levels of polar steroids including polyhydroxylated steroids and related glycosides in digestive organs of the starfish Patiria (=Asterina) pectinifera have been studied. The concentration of polar steroids is related to the annual reproductive cycle of the starfish and periods of active feeding. Two peaks in concentrations of polar steroids in pyloric caeca and stomach were found, the first in winter during reorganization and the second in summer during intensive gametogenesis before spawning. Probable biological functions of polyhydroxysteroids and related glycosides are discussed. The data support the hypothesis these compounds are involved in digestion in the starfish.
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The distribution of free sterols, polyhydroxysteroids and steroid glycosides in various body components of the starfish Patiria (=Asterina) pectinifera
Comparative biochemistry and physiology. Part B Biochemistry & molecular biology, 2001Co-Authors: Alla A. Kicha, N. V. Ivanchina, I. A. Gorshkova, Ljudmila P. Ponomarenko, Galina N. Likhatskaya, Valentin A. StonikAbstract:The distribution of free sterols, polyhydroxysteroids and steroid glycosides in different body components of the Far-eastern starfish Patiria (=Asterina) pectinifera has been studied. It was shown that free sterol fractions from aboral and oral body walls, gonads, stomach and pyloric ceca contained Delta(7) sterols with a preponderance of 5alpha-cholest-7-en-3beta-ol. All these body components had also toxic steroid oligoglycosides. However, polyhydroxysteroids and related low molecular weight steroid glycosides were found in stomach and pyloric ceca only. In pyloric ceca, the sulfated monoside 'asterosaponin' P(1) was identified as a main polar steroid, whereas 6-sodium sulfate of cholestane-3beta,4beta,6alpha,7alpha,8,15beta,16beta,26-octaol predominated in the stomach. Probable biological functions of polar steroids and free sterols in this starfish were discussed. It was suggested that some polyhydroxysteroids and related monoglycosides play the same biological role as bile alcohols and bile acids do in vertebrates.
Chiemi Inoue - One of the best experts on this subject based on the ideXlab platform.
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Germ Cell Differentiation in Starfish: The Posterior Enterocoel as the Origin of Germ Cells in Asterina pectinifera
Development Growth and Differentiation, 1992Co-Authors: Chiemi Inoue, Masato Kiyomoto, Hiroko ShiraiAbstract:The origin of germ cells of Asterina pectinifera was traced back to the posterior enterocoel (PE) of 2-day bipinnaria by two steps. First, the cellular cluster, composed of presumptive germ cells in the coelomic epithelium at brachiolaria stage, was confirmed to be the origin of the aboral haemal sinus located near the hydroporic canal (HC-AHS) by continuous observation of the formation process of HC-AHS. Second, the origin of the cluster was traced back to the PE of 2-day bipinnaria by comparison of the number of the presumptive germ cells in microsurgically PE-removed bipinnariae with that of non-operated control larvae. A summary of the differentiation of germ cells in Asterina pectinifera is given/presented.
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Origin of Germ Cells and Early Differentiation of Gonads in the Starfish, Asterina pectinifera. (starfish/germ cells/PGC/gonad/haemal sinus)
Development Growth & Differentiation, 1991Co-Authors: Chiemi Inoue, Hiroko ShiraiAbstract:The origin of the germ cells and the development of the genital system in the annually spawning starfish, Asterina pectinifera, were studied by light and electron microscopy. Characteristic germ cells were first characterized in gonads after spawning: the gonia are larger than somatic cells, have large nuclei (with electron-lucent nucleoplasm), and show mitochondrial aggregation associated with nuage (electron-dense bodies). In young starfish without gonads similar cells were detected in the haemal sinus, where they were termed primordial germ cells (PGCs). Brachiolariae and metamorphosed juveniles had a cellular cluster in the coelomic epithelium, near the hydroporic canal. The cluster was comprised of cells endowed with the above-mentioned characteristics of the germ cells. The germ cell counts indicated that PGCs migrate from the aboral haemal sinus near the hydroporic canal, through the haemal sinus to the gonads, where they settle, proliferate, and differentiate into gonia.
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origin of germ cells and early differentiation of gonads in the starfish Asterina pectinifera starfish germ cells pgc gonad haemal sinus
Development Growth & Differentiation, 1991Co-Authors: Chiemi Inoue, Hiroko ShiraiAbstract:The origin of the germ cells and the development of the genital system in the annually spawning starfish, Asterina pectinifera, were studied by light and electron microscopy. Characteristic germ cells were first characterized in gonads after spawning: the gonia are larger than somatic cells, have large nuclei (with electron-lucent nucleoplasm), and show mitochondrial aggregation associated with nuage (electron-dense bodies). In young starfish without gonads similar cells were detected in the haemal sinus, where they were termed primordial germ cells (PGCs). Brachiolariae and metamorphosed juveniles had a cellular cluster in the coelomic epithelium, near the hydroporic canal. The cluster was comprised of cells endowed with the above-mentioned characteristics of the germ cells. The germ cell counts indicated that PGCs migrate from the aboral haemal sinus near the hydroporic canal, through the haemal sinus to the gonads, where they settle, proliferate, and differentiate into gonia.
Hidekazu Katayama - One of the best experts on this subject based on the ideXlab platform.
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Enzyme-linked immunosorbent assay of relaxin-like gonad-stimulating peptide in the starfish Patiria (Asterina) pectinifera.
General and comparative endocrinology, 2017Co-Authors: Masatoshi Mita, Hidekazu KatayamaAbstract:Abstract A relaxin-like gonad-stimulating peptide (RGP) from starfish Patiria (Asterina) pectinifera is the first identified invertebrate gonadotropin for final gamete maturation. Recently, we succeeded in obtaining specific antibodies against P. pectinifera RGP (PpeRGP). In this study, the antibodies were used for the development of a specific and sensitive enzyme-linked immunosorbent assay (ELISA) for the measurement of PpeRGP. A biotin-conjugated peptide that binds to peroxidase-conjugated streptavidin is specifically detectable using 3,3′,5,5′-tetramethylbenzidine (TMB)/hydrogen peroxide as a substrate; therefore, biotin-conjugated RGP (biotin-PpeRGP) was synthesized chemically. Similarly to PpeRGP, synthetic biotin-PpeRGP bound to the antibody against PpeRGP. In binding experiments with biotin-PpeRGP using wells coated with the antibody, a displacement curve was obtained using serial concentrations of PpeRGP. The ELISA system showed that PpeRGP could be measured in the range 0.01–10 pmol per 50 µl assay buffer. On the contrary, the B-chains of PpeRGP, Asterias amurensis RGP, Aphelasterias japonica RGP, and human relaxin showed minimal cross-reactivity in the ELISA, except that the A-chain of PpeRGP affected it slightly. These results strongly suggest that this ELISA system is highly specific and sensitive with respect to PpeRGP.
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Radioimmunoassay of relaxin-like gonad-stimulating peptide in the starfish Patiria (=Asterina) pectinifera.
General and comparative endocrinology, 2016Co-Authors: Kazutoshi Yamamoto, Masato Kiyomoto, Hidekazu Katayama, Masatoshi MitaAbstract:Abstract A relaxin-like gonad-stimulating peptide (RGP) from starfish Patiria (= Asterina ) pectinifera is the first identified invertebrate gonadotropin for final gamete maturation. An antiserum against P. pectinifera RGP (PpeRGP) was produced by immunizing rabbits with a PpeRGP sulfanyl-polyethylene glycol derivative conjugated with keyhole limpet hemocyanin (KLH) as the antigen. The antiserum was used for the development of a specific and sensitive radioimmunoassay (RIA) for the measurement of RGP. In binding experiments using radioiodinated PpeRGP and antiserum against PpeRGP, a displacement curve was obtained using radioinert PpeRGP. The sensitivity of the RIA, defined as the amount of PpeRGP that significantly decreased the counts by 2 SD from the 100% bound point, averaged 0.040 ± 0.002 pmol PpeRGP per 100 μl assay buffer (0.40 ± 0.02 nM) in 10 assays. Intra-assay and inter-assay coefficients of variation were 6.1% and 2.7%, respectively. Serial dilution of whole homogenates from the radial nerve cords and circumoral nerve-rings of P. pectinifera produced displacement curves parallel to the PpeRGP standard. Thus, the amounts of PpeRGP were determined as 1.54 ± 0.09 pmol/mg wet weight of radial nerves and 0.87 ± 0.04 pmol/mg wet weight of nerve-rings, respectively. On contrary, pyloric stomach, pyloric caeca, tube-feet, ovaries, testes, and ovarian follicle cells did not react in the RIA system. Furthermore, the A- and B-chains of PpeRGP, Asterias amurensis RGP, bovine insulin, and human relaxin did not show cross-reactivity in the RIA. These results strongly suggest that the RIA system is a highly specific and sensitive with respect to PpeRGP.
