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Ryuichi Higuchi - One of the best experts on this subject based on the ideXlab platform.

  • constituents of holothuroidea 17 isolation and structure of biologically active monosialo gangliosides from the sea cucumber cucumaria echinata
    Chemical & Pharmaceutical Bulletin, 2006
    Co-Authors: Fumiaki Kisa, Masanori Inagaki, Tomofumi Miyamoto, Koji Yamada, Ryuichi Higuchi
    Abstract:

    Three new disialo- and trisialo-gangliosides, CEG-6 (6), CEG-8 (8), and CEG-9 (9), were obtained, together with one known ganglioside, HLG-3 (7), from the lipid fraction of the chloroform/methanol extract of the sea cucumber Cucumaria echinata. The structures of the new gangliosides were determined on the basis of chemical and spectroscopic evidence to be 1-O-[α-L-fucopyranosyl-(1→11)-(N-glycolyl-α-D-neuraminosyl)-(2→4)-(N-acetyl-α-D-neuraminosyl)-(2→6)-β-D-glucopyranosyl]-ceramide (6) and 1-O-[(N-glycolyl-D-neuraminosyl)-(2→11)-(N-glycolyl-D-neuraminosyl)-(2→4)-(N-acetyl-D-neuraminosyl)-(2→6)-D-glucopyranosyl]-ceramide (8, 9). The ceramide moieties of each compound were composed of an homogeneous sphingosine or phytosphingosine base and heterogeneous 2-hydroxy or nonhydroxylated fatty acid units. These gangliosides showed neuritogenic activity toward the rat Pheochromocytoma Cell Line PC-12 in the presence of nerve growth factor.

  • Biologically active glycosides from asteroidea, 42. Isolation and structure of a new biologically active ganglioside molecular species from the starfish Asterina pectinifera.
    Chemical & pharmaceutical bulletin, 2006
    Co-Authors: Ryuichi Higuchi, Tetsuya Komori, Shinichi Inoue, Kouji Inagaki, Maki Sakai, Tomofumi Miyamoto, Masanori Inagaki, Ryuichi Isobe
    Abstract:

    A ganglioside molecular species GP-3 (1) has been obtained from the water-soluble lipid fraction of the chloroform/methanol extract of the starfish Asterina pectinifera. The structure of the ganglioside has been determined on the basis of chemical and spectroscopic evidence. Compound 1 represents new ganglioside molecular species possessing two moles of sialic acids at the inner part of the sugar moiety. Partial hydrolysis by hot water and an enzymatic hydrolysis by means of endoglycoceramidase (EGCase) have proved useful for structure elucidation of the complex oligosaccharide moiety. Moreover, 1 exhibits neuritogenic activity toward the rat Pheochromocytoma Cell Line, PC-12 Cells, in the presence of nerve growth factor (NGF).

  • constituents of holothuroidea 10 isolation and structure of a biologically active ganglioside molecular species from the sea cucumber holothuria leucospilota
    Chemical & Pharmaceutical Bulletin, 2001
    Co-Authors: Koji Yamada, Tomofumi Miyamoto, Rei Matsubara, Masafumi Kaneko, Ryuichi Higuchi
    Abstract:

    Three ganglioside molecular species, HLG-1 (1), HLG-2 (2), and HLG-3 (3) have been obtained from the lipid fraction of the chloroform/methanol extract of the sea cucumber Holothuria leucospilota. The structures of these gangliosides have been determined, on the basis of chemical and spectroscopic evidence, as 1-O-[(N-glycolyl-α-D-neuraminosyl)-(2→6)-β-D-glucopyranosyl]-ceramide (1), 1-O-[(N-glycolyl-α-D-neuraminosyl)-(2→4)-(N-acetyl-α-D-neuraminosyl)-(2→6)-β-D-glucopyranosyl]-ceramide (2) and 1-O-[α-L-fucopyranosyl-(1→11)-(N-glycolyl-α-D-neuraminosyl)-(2→4)-(N-acetyl-α-D-neuraminosyl)-(2→6)-β-D-glucopyranosyl]-ceramide (3). The ceramide moieties were composed of heterogeneous phytosphingosine, sphingosine and 2-hydroxy fatty acid units. Compounds 2 and 3 represent new ganglioside molecular species. These three ganglioside molecular species showed neuritogenic activity toward the rat Pheochromocytoma Cell Line, PC-12 Cell, in the presence of NGF (nerve growth factor).

  • constituents of holothuroidea 9 isolation and structure of a new ganglioside molecular species from the sea cucumber holothuria pervicax
    Chemical & Pharmaceutical Bulletin, 2000
    Co-Authors: Koji Yamada, Ryuichi Isobe, Tomofumi Miyamoto, Yasuo Harada, Ryuichi Higuchi
    Abstract:

    A new ganglioside molecular species, HPG-7 (1) was obtained from the polar fraction of the chloroform/methanol extract of the sea cucumber, Holothuria pervicax. On the basis of chemical and spectroscopic evidence, the structure of 1 was determined, and the major component was 1-O-[alpha-L-fucopyranosyl-(1-->4)-(N-acetyl-alpha-D-neuraminosyl) - (2-->11)-(N-glycolyl-alpha-D-neuraminosyl)-(2-->4)-(N-acetyl -alpha-D- neuraminosyl)-(2-->6)-beta-D-glucopyranosyl]-(2S,3S,4R)-2-[(2R)-2- hydroxytetracosanoylamino]-14-methyl-hexadecane-1,3,4-triol. This is the first report on the isolation and structure elucidation of trisialo-ganglioside from sea cucumber. 1 showed neuritogenic activity toward the rat Pheochromocytoma Cell Line, PC-12 Cell.

  • isolation and structure of biologically active glycosphingolipids from the sea cucumber cucumaria echinata
    European Journal of Organic Chemistry, 1998
    Co-Authors: Koji Yamada, Ryuichi Higuchi, Tomofumi Miyamoto, Ryuichi Isobe, Eiji Hara, Seiichiroh Honda
    Abstract:

    Five cerebrosides, CE-1-1, CE-1-2, CE-1-3, CE-3-1, and CE-3-2, and a ganglioside molecular species CG-1 have been obtained from the less polar and polar fractions, respectively, of the chloroform/methanol extract of the sea cucumber Cucumaria echinata. The structures of these glycosphingolipids have been determined on the basis of chemical and spectroscopic evidence. The cerebrosides show lethality toward brine shrimps. On the other hand, the ganglioside CG-1 exhibits neuritogenic activity toward the rat Pheochromocytoma Cell Line, PC-12 Cells.

Koji Yamada - One of the best experts on this subject based on the ideXlab platform.

  • constituents of holothuroidea 17 isolation and structure of biologically active monosialo gangliosides from the sea cucumber cucumaria echinata
    Chemical & Pharmaceutical Bulletin, 2006
    Co-Authors: Fumiaki Kisa, Masanori Inagaki, Tomofumi Miyamoto, Koji Yamada, Ryuichi Higuchi
    Abstract:

    Three new disialo- and trisialo-gangliosides, CEG-6 (6), CEG-8 (8), and CEG-9 (9), were obtained, together with one known ganglioside, HLG-3 (7), from the lipid fraction of the chloroform/methanol extract of the sea cucumber Cucumaria echinata. The structures of the new gangliosides were determined on the basis of chemical and spectroscopic evidence to be 1-O-[α-L-fucopyranosyl-(1→11)-(N-glycolyl-α-D-neuraminosyl)-(2→4)-(N-acetyl-α-D-neuraminosyl)-(2→6)-β-D-glucopyranosyl]-ceramide (6) and 1-O-[(N-glycolyl-D-neuraminosyl)-(2→11)-(N-glycolyl-D-neuraminosyl)-(2→4)-(N-acetyl-D-neuraminosyl)-(2→6)-D-glucopyranosyl]-ceramide (8, 9). The ceramide moieties of each compound were composed of an homogeneous sphingosine or phytosphingosine base and heterogeneous 2-hydroxy or nonhydroxylated fatty acid units. These gangliosides showed neuritogenic activity toward the rat Pheochromocytoma Cell Line PC-12 in the presence of nerve growth factor.

  • constituents of holothuroidea 10 isolation and structure of a biologically active ganglioside molecular species from the sea cucumber holothuria leucospilota
    Chemical & Pharmaceutical Bulletin, 2001
    Co-Authors: Koji Yamada, Tomofumi Miyamoto, Rei Matsubara, Masafumi Kaneko, Ryuichi Higuchi
    Abstract:

    Three ganglioside molecular species, HLG-1 (1), HLG-2 (2), and HLG-3 (3) have been obtained from the lipid fraction of the chloroform/methanol extract of the sea cucumber Holothuria leucospilota. The structures of these gangliosides have been determined, on the basis of chemical and spectroscopic evidence, as 1-O-[(N-glycolyl-α-D-neuraminosyl)-(2→6)-β-D-glucopyranosyl]-ceramide (1), 1-O-[(N-glycolyl-α-D-neuraminosyl)-(2→4)-(N-acetyl-α-D-neuraminosyl)-(2→6)-β-D-glucopyranosyl]-ceramide (2) and 1-O-[α-L-fucopyranosyl-(1→11)-(N-glycolyl-α-D-neuraminosyl)-(2→4)-(N-acetyl-α-D-neuraminosyl)-(2→6)-β-D-glucopyranosyl]-ceramide (3). The ceramide moieties were composed of heterogeneous phytosphingosine, sphingosine and 2-hydroxy fatty acid units. Compounds 2 and 3 represent new ganglioside molecular species. These three ganglioside molecular species showed neuritogenic activity toward the rat Pheochromocytoma Cell Line, PC-12 Cell, in the presence of NGF (nerve growth factor).

  • constituents of holothuroidea 9 isolation and structure of a new ganglioside molecular species from the sea cucumber holothuria pervicax
    Chemical & Pharmaceutical Bulletin, 2000
    Co-Authors: Koji Yamada, Ryuichi Isobe, Tomofumi Miyamoto, Yasuo Harada, Ryuichi Higuchi
    Abstract:

    A new ganglioside molecular species, HPG-7 (1) was obtained from the polar fraction of the chloroform/methanol extract of the sea cucumber, Holothuria pervicax. On the basis of chemical and spectroscopic evidence, the structure of 1 was determined, and the major component was 1-O-[alpha-L-fucopyranosyl-(1-->4)-(N-acetyl-alpha-D-neuraminosyl) - (2-->11)-(N-glycolyl-alpha-D-neuraminosyl)-(2-->4)-(N-acetyl -alpha-D- neuraminosyl)-(2-->6)-beta-D-glucopyranosyl]-(2S,3S,4R)-2-[(2R)-2- hydroxytetracosanoylamino]-14-methyl-hexadecane-1,3,4-triol. This is the first report on the isolation and structure elucidation of trisialo-ganglioside from sea cucumber. 1 showed neuritogenic activity toward the rat Pheochromocytoma Cell Line, PC-12 Cell.

  • isolation and structure of biologically active glycosphingolipids from the sea cucumber cucumaria echinata
    European Journal of Organic Chemistry, 1998
    Co-Authors: Koji Yamada, Ryuichi Higuchi, Tomofumi Miyamoto, Ryuichi Isobe, Eiji Hara, Seiichiroh Honda
    Abstract:

    Five cerebrosides, CE-1-1, CE-1-2, CE-1-3, CE-3-1, and CE-3-2, and a ganglioside molecular species CG-1 have been obtained from the less polar and polar fractions, respectively, of the chloroform/methanol extract of the sea cucumber Cucumaria echinata. The structures of these glycosphingolipids have been determined on the basis of chemical and spectroscopic evidence. The cerebrosides show lethality toward brine shrimps. On the other hand, the ganglioside CG-1 exhibits neuritogenic activity toward the rat Pheochromocytoma Cell Line, PC-12 Cells.

Tomofumi Miyamoto - One of the best experts on this subject based on the ideXlab platform.

  • constituents of holothuroidea 17 isolation and structure of biologically active monosialo gangliosides from the sea cucumber cucumaria echinata
    Chemical & Pharmaceutical Bulletin, 2006
    Co-Authors: Fumiaki Kisa, Masanori Inagaki, Tomofumi Miyamoto, Koji Yamada, Ryuichi Higuchi
    Abstract:

    Three new disialo- and trisialo-gangliosides, CEG-6 (6), CEG-8 (8), and CEG-9 (9), were obtained, together with one known ganglioside, HLG-3 (7), from the lipid fraction of the chloroform/methanol extract of the sea cucumber Cucumaria echinata. The structures of the new gangliosides were determined on the basis of chemical and spectroscopic evidence to be 1-O-[α-L-fucopyranosyl-(1→11)-(N-glycolyl-α-D-neuraminosyl)-(2→4)-(N-acetyl-α-D-neuraminosyl)-(2→6)-β-D-glucopyranosyl]-ceramide (6) and 1-O-[(N-glycolyl-D-neuraminosyl)-(2→11)-(N-glycolyl-D-neuraminosyl)-(2→4)-(N-acetyl-D-neuraminosyl)-(2→6)-D-glucopyranosyl]-ceramide (8, 9). The ceramide moieties of each compound were composed of an homogeneous sphingosine or phytosphingosine base and heterogeneous 2-hydroxy or nonhydroxylated fatty acid units. These gangliosides showed neuritogenic activity toward the rat Pheochromocytoma Cell Line PC-12 in the presence of nerve growth factor.

  • Biologically active glycosides from asteroidea, 42. Isolation and structure of a new biologically active ganglioside molecular species from the starfish Asterina pectinifera.
    Chemical & pharmaceutical bulletin, 2006
    Co-Authors: Ryuichi Higuchi, Tetsuya Komori, Shinichi Inoue, Kouji Inagaki, Maki Sakai, Tomofumi Miyamoto, Masanori Inagaki, Ryuichi Isobe
    Abstract:

    A ganglioside molecular species GP-3 (1) has been obtained from the water-soluble lipid fraction of the chloroform/methanol extract of the starfish Asterina pectinifera. The structure of the ganglioside has been determined on the basis of chemical and spectroscopic evidence. Compound 1 represents new ganglioside molecular species possessing two moles of sialic acids at the inner part of the sugar moiety. Partial hydrolysis by hot water and an enzymatic hydrolysis by means of endoglycoceramidase (EGCase) have proved useful for structure elucidation of the complex oligosaccharide moiety. Moreover, 1 exhibits neuritogenic activity toward the rat Pheochromocytoma Cell Line, PC-12 Cells, in the presence of nerve growth factor (NGF).

  • constituents of holothuroidea 10 isolation and structure of a biologically active ganglioside molecular species from the sea cucumber holothuria leucospilota
    Chemical & Pharmaceutical Bulletin, 2001
    Co-Authors: Koji Yamada, Tomofumi Miyamoto, Rei Matsubara, Masafumi Kaneko, Ryuichi Higuchi
    Abstract:

    Three ganglioside molecular species, HLG-1 (1), HLG-2 (2), and HLG-3 (3) have been obtained from the lipid fraction of the chloroform/methanol extract of the sea cucumber Holothuria leucospilota. The structures of these gangliosides have been determined, on the basis of chemical and spectroscopic evidence, as 1-O-[(N-glycolyl-α-D-neuraminosyl)-(2→6)-β-D-glucopyranosyl]-ceramide (1), 1-O-[(N-glycolyl-α-D-neuraminosyl)-(2→4)-(N-acetyl-α-D-neuraminosyl)-(2→6)-β-D-glucopyranosyl]-ceramide (2) and 1-O-[α-L-fucopyranosyl-(1→11)-(N-glycolyl-α-D-neuraminosyl)-(2→4)-(N-acetyl-α-D-neuraminosyl)-(2→6)-β-D-glucopyranosyl]-ceramide (3). The ceramide moieties were composed of heterogeneous phytosphingosine, sphingosine and 2-hydroxy fatty acid units. Compounds 2 and 3 represent new ganglioside molecular species. These three ganglioside molecular species showed neuritogenic activity toward the rat Pheochromocytoma Cell Line, PC-12 Cell, in the presence of NGF (nerve growth factor).

  • constituents of holothuroidea 9 isolation and structure of a new ganglioside molecular species from the sea cucumber holothuria pervicax
    Chemical & Pharmaceutical Bulletin, 2000
    Co-Authors: Koji Yamada, Ryuichi Isobe, Tomofumi Miyamoto, Yasuo Harada, Ryuichi Higuchi
    Abstract:

    A new ganglioside molecular species, HPG-7 (1) was obtained from the polar fraction of the chloroform/methanol extract of the sea cucumber, Holothuria pervicax. On the basis of chemical and spectroscopic evidence, the structure of 1 was determined, and the major component was 1-O-[alpha-L-fucopyranosyl-(1-->4)-(N-acetyl-alpha-D-neuraminosyl) - (2-->11)-(N-glycolyl-alpha-D-neuraminosyl)-(2-->4)-(N-acetyl -alpha-D- neuraminosyl)-(2-->6)-beta-D-glucopyranosyl]-(2S,3S,4R)-2-[(2R)-2- hydroxytetracosanoylamino]-14-methyl-hexadecane-1,3,4-triol. This is the first report on the isolation and structure elucidation of trisialo-ganglioside from sea cucumber. 1 showed neuritogenic activity toward the rat Pheochromocytoma Cell Line, PC-12 Cell.

  • isolation and structure of biologically active glycosphingolipids from the sea cucumber cucumaria echinata
    European Journal of Organic Chemistry, 1998
    Co-Authors: Koji Yamada, Ryuichi Higuchi, Tomofumi Miyamoto, Ryuichi Isobe, Eiji Hara, Seiichiroh Honda
    Abstract:

    Five cerebrosides, CE-1-1, CE-1-2, CE-1-3, CE-3-1, and CE-3-2, and a ganglioside molecular species CG-1 have been obtained from the less polar and polar fractions, respectively, of the chloroform/methanol extract of the sea cucumber Cucumaria echinata. The structures of these glycosphingolipids have been determined on the basis of chemical and spectroscopic evidence. The cerebrosides show lethality toward brine shrimps. On the other hand, the ganglioside CG-1 exhibits neuritogenic activity toward the rat Pheochromocytoma Cell Line, PC-12 Cells.

Seiichiroh Honda - One of the best experts on this subject based on the ideXlab platform.

  • isolation and structure of biologically active glycosphingolipids from the sea cucumber cucumaria echinata
    European Journal of Organic Chemistry, 1998
    Co-Authors: Koji Yamada, Ryuichi Higuchi, Tomofumi Miyamoto, Ryuichi Isobe, Eiji Hara, Seiichiroh Honda
    Abstract:

    Five cerebrosides, CE-1-1, CE-1-2, CE-1-3, CE-3-1, and CE-3-2, and a ganglioside molecular species CG-1 have been obtained from the less polar and polar fractions, respectively, of the chloroform/methanol extract of the sea cucumber Cucumaria echinata. The structures of these glycosphingolipids have been determined on the basis of chemical and spectroscopic evidence. The cerebrosides show lethality toward brine shrimps. On the other hand, the ganglioside CG-1 exhibits neuritogenic activity toward the rat Pheochromocytoma Cell Line, PC-12 Cells.

Victor J. Dzau - One of the best experts on this subject based on the ideXlab platform.

  • angiotensin type 2 receptor dephosphorylates bcl 2 by activating mitogen activated protein kinase phosphatase 1 and induces apoptosis
    Journal of Biological Chemistry, 1997
    Co-Authors: Masatsugu Horiuchi, Wataru Hayashida, Toshie Kambe, Takehiko Yamada, Victor J. Dzau
    Abstract:

    Abstract We examined the Cellular and signaling mechanism of angiotensin II (Ang II) type 2 (AT2) receptor-induced apoptosis in PC12W (rat Pheochromocytoma Cell Line) Cells that express abundant AT2 receptor but not Ang II type 1 receptor. In these Cells, nerve growth factor (NGF) inhibited the internucleosomal DNA fragmentation induced by serum depletion, whereas Ang II antagonized this NGF Cell survival action and induced apoptosis. We studied the mechanism of NGF and AT2 receptor interaction on apoptosis by examining their effects on the survival factor Bcl-2. AT2 receptor activation did affect intraCellular Bcl-2 protein levels. Bcl-2 phosphorylation was stimulated by NGF, whereas AT2 receptor activation blocked this NGF effect. Pretreatment with antisense oligonucleotide of mitogen-activated protein (MAP) kinase phosphatase-1 enhanced the effects of NGF on MAP kinase activation and Bcl-2 phosphorylation but attenuated the inhibitory effects of AT2 receptor on MAP kinase, Bcl-2 phosphorylation, and apoptosis. Taken together, these results suggest that MAP kinase plays a critical role in inhibiting apoptosis by phosphorylating Bcl-2. The AT2 receptor inhibits MAP kinase activation, resulting in the inactivation of Bcl-2 and the induction of apoptosis.

  • angiotensin ii type 2 receptor mediates programmed Cell death
    Proceedings of the National Academy of Sciences of the United States of America, 1996
    Co-Authors: Takehiko Yamada, Masatsugu Horiuchi, Victor J. Dzau
    Abstract:

    The function of the recently discovered angiotensin II type 2 (AT2) receptor remains elusive. This receptor is expressed abundantly in fetus, but scantily in adult tissues except brain, adrenal medulla, and atretic ovary. In this study, we demonstrated that this receptor mediates programmed Cell death (apoptosis). We observed this effect in PC12W Cells (rat Pheochromocytoma Cell Line) and R3T3 Cells (mouse fibroblast Cell Line), which express abundant AT2 receptor but not AT1 receptor. The Cellular mechanism appears to involve the dephosphorylation of mitogen-activated protein kinase (MAP kinase). Vanadate, a protein-tyrosine-phosphatase inhibitor, attenuated the dephosphorylation of MAP kinases by the AT2 receptor and restored the apoptotic changes. Antisense oligonucleotide to MAP kinase phosphatase 1 inhibited the AT2 receptor-mediated MAP kinase dephosphorylation and blocked the AT2 receptor-mediated apoptosis. These results suggest that protein-tyrosine-phosphatase, including MAP kinase phosphatase 1 activated by the AT2 receptor, is involved in apoptosis. We hypothesize that this apoptotic function of the AT2 receptor may play an important role in developmental biology and pathophysiology.