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Mamiko Ozaki - One of the best experts on this subject based on the ideXlab platform.

  • A novel Takeout-like protein expressed in the taste and olfactory organs of the blowfly, Phormia regina.
    The FEBS journal, 2006
    Co-Authors: Kazuyo Fujikawa, Keiji Seno, Mamiko Ozaki
    Abstract:

    In insects, the functional molecules responsible for the taste system are still obscure. The gene for a 28.5 kDa protein purified from taste sensilla of the blowfly Phormia regina belongs to a gene family that includes takeout of Drosophila melanogaster. Molecular phylogenetic analysis revealed that the Phormia Takeout-like protein is most similar to the protein encoded by a member of the Drosophila takeout gene family, CG14661, whose expression and function have not been identified yet. Western blot analyses revealed that Phormia Takeout-like protein was exclusively expressed in antennae and labellum of the adult blowfly in both sexes. Immunohistochemical experiments demonstrated that Takeout-like protein was localized around the lamella structure of the auxiliary cells and in the sensillar lymph of the labellar taste sensillum. In antennae, Takeout-like protein was distributed at the base of the olfactory sensilla as well. No significant differences in Takeout-like protein expression were found between the sexes. Our results suggest that Phormia Takeout-like protein is involved in some early events concerned with chemoreception in both the taste and olfactory systems.

  • Gqα subunit mediates receptor site-specific adaptation in the sugar taste receptor cell of the blowfly, Phormia regina
    Neuroscience letters, 2005
    Co-Authors: Keiji Seno, Kazuyo Fujikawa, Tadashi Nakamura, Mamiko Ozaki
    Abstract:

    Abstract The gustatory system is essential for almost all animals. The recent identification of G protein-coupled receptor proteins (GPCRs) has progressed molecular biological studies of gustatory systems, although the signal transduction mechanisms have not yet been fully elucidated. In vision and olfactory receptor cells, G q class G protein is known to be a major signal transducer. By functional blocking of intrinsic G q with an anti-G q/11 α antibody, we investigated the roles of G q in the sugar receptor cell of the blowfly, Phormia regina . Before and after introduction of the anti-G q/11 α antibody into the cell through the DOC-permeabilized cell membrane, we recorded the responses of the receptor cell to sucrose and d -fructose, which stimulate different receptor sites, respectively. The initial impulse frequency in response to either sucrose or d -fructose was not changed by antibody introduction, whereas the adaptation rate in sucrose stimulation, but not fructose stimulation, became slower after antibody introduction. These results indicate that: (1) G q is a regulator of adaptation in the sugar receptor cell of Phormia , rather than a transducer, and (2) different adaptation mechanisms are promoted by stimulations with sucrose and d -fructose.

Jean-paul Delbecque - One of the best experts on this subject based on the ideXlab platform.

  • Calcium inhibits ovarian steroidogenesis in the blowfly Phormia regina
    2015
    Co-Authors: Gérard Manière, Elisabeth Vanhems, F Gautron, Jean-paul Delbecque
    Abstract:

    Calcium is frequently involved in the stimulation of steroidogenesis in gonads and endocrine glands, generally in association with cAMP. However, our present obser-vations show that it has the opposite effect in the ovary of the blowfly Phormia regina. Our in vitro experiments first showed that extracellular calcium does not play a role during the stimulation of steroidogenesis in fly ovaries; indeed steroidogenesis was activated in vitro as efficiently in a medium with or without calcium, either by pharmaco-logical compounds mimicking cAMP signaling or by active brain extracts. When calcium was experimentally introduced into biosynthetic cells by ionophores or liber-ated from internal stores by thapsigargin, it did not activate, but clearly inhibited both basal and acute steroidogenesis respectively in previtellogenic and in vitellogenic ovaries. Our experiments also demonstrated that calcium decreases cAMP concentrations in the ovaries of Phormia, by stimulating its degradation, without modifying its biosynthesis. Moreover, inhibitors of calcium–calmodulin phosphodiesterases (PDEs) increased steroid biosynthesis in vitro, whereas inhibitors of calcium-insensitive PDEs did not. These data thus demonstrate that, in blowfly ovaries, calcium ions inhibit cAMP-stimulated steroidogenesis by activating a calmodulin-sensitive (type I) PDE. Journal of Endocrinology (2002) 173, 533–54

  • Calcium inhibits ovarian steroidogenesis in the blowfly Phormia regina.
    Journal of Endocrinology, 2002
    Co-Authors: Gérard Manière, Elisabeth Vanhems, F Gautron, Jean-paul Delbecque
    Abstract:

    Calcium is frequently involved in the stimulation of steroidogenesis in gonads and endocrine glands, generally in association with cAMP. However, our present observations show that it has the opposite effect in the ovary of the blowfly Phormia regina. Our in vitro experiments first showed that extracellular calcium does not play a role during the stimulation of steroidogenesis in fly ovaries; indeed steroidogenesis was activated in vitro as efficiently in a medium with or without calcium, either by pharmacological compounds mimicking cAMP signaling or by active brain extracts. When calcium was experimentally introduced into biosynthetic cells by ionophores or liberated from internal stores by thapsigargin, it did not activate, but clearly inhibited both basal and acute steroidogenesis respectively in previtellogenic and in vitellogenic ovaries. Our experiments also demonstrated that calcium decreases cAMP concentrations in the ovaries of Phormia, by stimulating its degradation, without modifying its biosynthesis. Moreover, inhibitors of calcium‐calmodulin phosphodiesterases (PDEs) increased steroid biosynthesis in vitro, whereas inhibitors of calciuminsensitive PDEs did not. These data thus demonstrate that, in blowfly ovaries, calcium ions inhibit cAMPstimulated steroidogenesis by activating a calmodulinsensitive (type I) PDE.

  • Calcium inhibits ovarian steroidogenesis in the blowfly Phormia regina.
    Journal of Endocrinology, 2002
    Co-Authors: Gérard Manière, Elisabeth Vanhems, F Gautron, Jean-paul Delbecque
    Abstract:

    Calcium is frequently involved in the stimulation of steroidogenesis in gonads and endocrine glands, generally in association with cAMP. However, our present observations show that it has the opposite effect in the ovary of the blowfly Phormia regina. Our in vitro experiments first showed that extracellular calcium does not play a role during the stimulation of steroidogenesis in fly ovaries; indeed steroidogenesis was activated in vitro as efficiently in a medium with or without calcium, either by pharmacological compounds mimicking cAMP signaling or by active brain extracts. When calcium was experimentally introduced into biosynthetic cells by ionophores or liberated from internal stores by thapsigargin, it did not activate, but clearly inhibited both basal and acute steroidogenesis respectively in previtellogenic and in vitellogenic ovaries. Our experiments also demonstrated that calcium decreases cAMP concentrations in the ovaries of Phormia, by stimulating its degradation, without modifying its biosynthesis. Moreover, inhibitors of calcium‐calmodulin phosphodiesterases (PDEs) increased steroid biosynthesis in vitro, whereas inhibitors of calciuminsensitive PDEs did not. These data thus demonstrate that, in blowfly ovaries, calcium ions inhibit cAMPstimulated steroidogenesis by activating a calmodulinsensitive (type I) PDE.

Keiji Seno - One of the best experts on this subject based on the ideXlab platform.

  • A novel Takeout-like protein expressed in the taste and olfactory organs of the blowfly, Phormia regina.
    The FEBS journal, 2006
    Co-Authors: Kazuyo Fujikawa, Keiji Seno, Mamiko Ozaki
    Abstract:

    In insects, the functional molecules responsible for the taste system are still obscure. The gene for a 28.5 kDa protein purified from taste sensilla of the blowfly Phormia regina belongs to a gene family that includes takeout of Drosophila melanogaster. Molecular phylogenetic analysis revealed that the Phormia Takeout-like protein is most similar to the protein encoded by a member of the Drosophila takeout gene family, CG14661, whose expression and function have not been identified yet. Western blot analyses revealed that Phormia Takeout-like protein was exclusively expressed in antennae and labellum of the adult blowfly in both sexes. Immunohistochemical experiments demonstrated that Takeout-like protein was localized around the lamella structure of the auxiliary cells and in the sensillar lymph of the labellar taste sensillum. In antennae, Takeout-like protein was distributed at the base of the olfactory sensilla as well. No significant differences in Takeout-like protein expression were found between the sexes. Our results suggest that Phormia Takeout-like protein is involved in some early events concerned with chemoreception in both the taste and olfactory systems.

  • Gqα subunit mediates receptor site-specific adaptation in the sugar taste receptor cell of the blowfly, Phormia regina
    Neuroscience letters, 2005
    Co-Authors: Keiji Seno, Kazuyo Fujikawa, Tadashi Nakamura, Mamiko Ozaki
    Abstract:

    Abstract The gustatory system is essential for almost all animals. The recent identification of G protein-coupled receptor proteins (GPCRs) has progressed molecular biological studies of gustatory systems, although the signal transduction mechanisms have not yet been fully elucidated. In vision and olfactory receptor cells, G q class G protein is known to be a major signal transducer. By functional blocking of intrinsic G q with an anti-G q/11 α antibody, we investigated the roles of G q in the sugar receptor cell of the blowfly, Phormia regina . Before and after introduction of the anti-G q/11 α antibody into the cell through the DOC-permeabilized cell membrane, we recorded the responses of the receptor cell to sucrose and d -fructose, which stimulate different receptor sites, respectively. The initial impulse frequency in response to either sucrose or d -fructose was not changed by antibody introduction, whereas the adaptation rate in sucrose stimulation, but not fructose stimulation, became slower after antibody introduction. These results indicate that: (1) G q is a regulator of adaptation in the sugar receptor cell of Phormia , rather than a transducer, and (2) different adaptation mechanisms are promoted by stimulations with sucrose and d -fructose.

Gérard Manière - One of the best experts on this subject based on the ideXlab platform.

  • Calcium inhibits ovarian steroidogenesis in the blowfly Phormia regina
    2015
    Co-Authors: Gérard Manière, Elisabeth Vanhems, F Gautron, Jean-paul Delbecque
    Abstract:

    Calcium is frequently involved in the stimulation of steroidogenesis in gonads and endocrine glands, generally in association with cAMP. However, our present obser-vations show that it has the opposite effect in the ovary of the blowfly Phormia regina. Our in vitro experiments first showed that extracellular calcium does not play a role during the stimulation of steroidogenesis in fly ovaries; indeed steroidogenesis was activated in vitro as efficiently in a medium with or without calcium, either by pharmaco-logical compounds mimicking cAMP signaling or by active brain extracts. When calcium was experimentally introduced into biosynthetic cells by ionophores or liber-ated from internal stores by thapsigargin, it did not activate, but clearly inhibited both basal and acute steroidogenesis respectively in previtellogenic and in vitellogenic ovaries. Our experiments also demonstrated that calcium decreases cAMP concentrations in the ovaries of Phormia, by stimulating its degradation, without modifying its biosynthesis. Moreover, inhibitors of calcium–calmodulin phosphodiesterases (PDEs) increased steroid biosynthesis in vitro, whereas inhibitors of calcium-insensitive PDEs did not. These data thus demonstrate that, in blowfly ovaries, calcium ions inhibit cAMP-stimulated steroidogenesis by activating a calmodulin-sensitive (type I) PDE. Journal of Endocrinology (2002) 173, 533–54

  • Calcium inhibits ovarian steroidogenesis in the blowfly Phormia regina.
    Journal of Endocrinology, 2002
    Co-Authors: Gérard Manière, Elisabeth Vanhems, F Gautron, Jean-paul Delbecque
    Abstract:

    Calcium is frequently involved in the stimulation of steroidogenesis in gonads and endocrine glands, generally in association with cAMP. However, our present observations show that it has the opposite effect in the ovary of the blowfly Phormia regina. Our in vitro experiments first showed that extracellular calcium does not play a role during the stimulation of steroidogenesis in fly ovaries; indeed steroidogenesis was activated in vitro as efficiently in a medium with or without calcium, either by pharmacological compounds mimicking cAMP signaling or by active brain extracts. When calcium was experimentally introduced into biosynthetic cells by ionophores or liberated from internal stores by thapsigargin, it did not activate, but clearly inhibited both basal and acute steroidogenesis respectively in previtellogenic and in vitellogenic ovaries. Our experiments also demonstrated that calcium decreases cAMP concentrations in the ovaries of Phormia, by stimulating its degradation, without modifying its biosynthesis. Moreover, inhibitors of calcium‐calmodulin phosphodiesterases (PDEs) increased steroid biosynthesis in vitro, whereas inhibitors of calciuminsensitive PDEs did not. These data thus demonstrate that, in blowfly ovaries, calcium ions inhibit cAMPstimulated steroidogenesis by activating a calmodulinsensitive (type I) PDE.

  • Calcium inhibits ovarian steroidogenesis in the blowfly Phormia regina.
    Journal of Endocrinology, 2002
    Co-Authors: Gérard Manière, Elisabeth Vanhems, F Gautron, Jean-paul Delbecque
    Abstract:

    Calcium is frequently involved in the stimulation of steroidogenesis in gonads and endocrine glands, generally in association with cAMP. However, our present observations show that it has the opposite effect in the ovary of the blowfly Phormia regina. Our in vitro experiments first showed that extracellular calcium does not play a role during the stimulation of steroidogenesis in fly ovaries; indeed steroidogenesis was activated in vitro as efficiently in a medium with or without calcium, either by pharmacological compounds mimicking cAMP signaling or by active brain extracts. When calcium was experimentally introduced into biosynthetic cells by ionophores or liberated from internal stores by thapsigargin, it did not activate, but clearly inhibited both basal and acute steroidogenesis respectively in previtellogenic and in vitellogenic ovaries. Our experiments also demonstrated that calcium decreases cAMP concentrations in the ovaries of Phormia, by stimulating its degradation, without modifying its biosynthesis. Moreover, inhibitors of calcium‐calmodulin phosphodiesterases (PDEs) increased steroid biosynthesis in vitro, whereas inhibitors of calciuminsensitive PDEs did not. These data thus demonstrate that, in blowfly ovaries, calcium ions inhibit cAMPstimulated steroidogenesis by activating a calmodulinsensitive (type I) PDE.

Kazuyo Fujikawa - One of the best experts on this subject based on the ideXlab platform.

  • A novel Takeout-like protein expressed in the taste and olfactory organs of the blowfly, Phormia regina.
    The FEBS journal, 2006
    Co-Authors: Kazuyo Fujikawa, Keiji Seno, Mamiko Ozaki
    Abstract:

    In insects, the functional molecules responsible for the taste system are still obscure. The gene for a 28.5 kDa protein purified from taste sensilla of the blowfly Phormia regina belongs to a gene family that includes takeout of Drosophila melanogaster. Molecular phylogenetic analysis revealed that the Phormia Takeout-like protein is most similar to the protein encoded by a member of the Drosophila takeout gene family, CG14661, whose expression and function have not been identified yet. Western blot analyses revealed that Phormia Takeout-like protein was exclusively expressed in antennae and labellum of the adult blowfly in both sexes. Immunohistochemical experiments demonstrated that Takeout-like protein was localized around the lamella structure of the auxiliary cells and in the sensillar lymph of the labellar taste sensillum. In antennae, Takeout-like protein was distributed at the base of the olfactory sensilla as well. No significant differences in Takeout-like protein expression were found between the sexes. Our results suggest that Phormia Takeout-like protein is involved in some early events concerned with chemoreception in both the taste and olfactory systems.

  • Gqα subunit mediates receptor site-specific adaptation in the sugar taste receptor cell of the blowfly, Phormia regina
    Neuroscience letters, 2005
    Co-Authors: Keiji Seno, Kazuyo Fujikawa, Tadashi Nakamura, Mamiko Ozaki
    Abstract:

    Abstract The gustatory system is essential for almost all animals. The recent identification of G protein-coupled receptor proteins (GPCRs) has progressed molecular biological studies of gustatory systems, although the signal transduction mechanisms have not yet been fully elucidated. In vision and olfactory receptor cells, G q class G protein is known to be a major signal transducer. By functional blocking of intrinsic G q with an anti-G q/11 α antibody, we investigated the roles of G q in the sugar receptor cell of the blowfly, Phormia regina . Before and after introduction of the anti-G q/11 α antibody into the cell through the DOC-permeabilized cell membrane, we recorded the responses of the receptor cell to sucrose and d -fructose, which stimulate different receptor sites, respectively. The initial impulse frequency in response to either sucrose or d -fructose was not changed by antibody introduction, whereas the adaptation rate in sucrose stimulation, but not fructose stimulation, became slower after antibody introduction. These results indicate that: (1) G q is a regulator of adaptation in the sugar receptor cell of Phormia , rather than a transducer, and (2) different adaptation mechanisms are promoted by stimulations with sucrose and d -fructose.