＜Series : S\u27interroger sur I\u27mplicite>S’interroger sur l’implicite III － Corps, Espace, Sensibilité : Report: The Implicitness of Landscape : Sensibilities, Negative Memories, and Violence

シリーズ「語りえぬものを問う」国際シンポジウム語りえぬものを問うIII──身体・空間・感性──S’interroger sur l’impliciteⅢ－Corps, Espace, Sensibilité2005年10月30日（日）関西学院大学西宮上ヶ原キャンパス関西学院会

Activator protein-1 responsive to the group II metabotropic glutamate receptor subtype in association with intracellular calcium in cultured rat cortical neurons

金沢大学大学院自然科学研究科分子作用学Activation of ionotropic glutamate (Glu) receptors, such as N-methyl-d-aspartate receptors, is shown to modulate the gene transcription mediated by the transcription factor activator protein-1 (AP1) composed of Fos and Jun family proteins in the brain, while little attention has been paid to the modulation of AP1 expression by metabotropic Glu receptors (mGluRs). In cultured rat cortical neurons, where constitutive expression was seen with all groups I, II and III mGluR subtypes, a significant and selective increase was seen in the DNA binding activity of AP1 120 min after the brief exposure to the group II mGluR agonist (2S,2′R,3′R)-2-(2′,3′-dicarboxycyclopropyl)glycine (DCG-IV) for 5 min. In cultured rat cortical astrocytes, by contrast, a significant increase was induced by a group I mGluR agonist, but not by either a group II or III mGluR agonist. The increase by DCG-IV was significantly prevented by a group II mGluR antagonist as well as by either an intracellular Ca2+ chelator or a voltage-sensitive Ca2+ channel blocker, but not by an intracellular Ca2+ store inhibitor. Moreover, DCG-IV significantly prevented the increase of cAMP formation by forskolin in cultured neurons. Western blot analysis revealed differential expression profiles of Fos family members in neurons briefly exposed to DCG-IV and NMDA. Prior or simultaneous exposure to DCG-IV led to significant protection against neuronal cell death by NMDA. These results suggest that activation of the group II mGluR subtype would modulate the gene expression mediated by AP1 through increased intracellular Ca2+ levels in cultured rat cortical neurons. © 2007

Developmental genetic bases behind the independent origin of the tympanic membrane in mammals and diapsids

International audienceThe amniote middle ear is a classical example of the evolutionary novelty. Although paleontological evidence supports the view that mammals and diapsids (modern reptiles and birds) independently acquired the middle ear after divergence from their common ancestor, the developmental bases of these transformations remain unknown. Here we show that lower-to-upper jaw transformation induced by inactivation of the Endothelin1-Dlx5/6 cascade involving Goosecoid results in loss of the tympanic membrane in mouse, but causes duplication of the tympanic membrane in chicken. Detailed anatomical analysis indicates that the relative positions of the primary jaw joint and first pharyngeal pouch led to the coupling of tympanic membrane formation with the lower jaw in mammals, but with the upper jaw in diapsids. We propose that differences in connection and release by various pharyngeal skeletal elements resulted in structural diversity, leading to the acquisition of the tympanic membrane in two distinct manners during amniote evolution

Isolation and characterization of a novel 2-sec-butylphenol-degrading bacterium Pseudomonas sp. strain MS-1

A novel bacterium capable of utilizing 2-sec-butylphenol as the sole carbon and energy source, Pseudomonas sp. strain MS-1, was isolated from freshwater sediment. Within 30 h, strain MS-1 completely degraded 1.5 mM 2-sec-butylphenol in basal salt medium, with concomitant cell growth. A pathway for the metabolism of 2-sec-butylphenol by strain MS-1 was proposed on the basis of the identification of 3 internal metabolites—3-sec-butylcatechol, 2-hydroxy-6-oxo-7-methylnona-2,4-dienoic acid, and 2-methylbutyric acid—by gas chromatography-mass spectrometry analysis. Strain MS-1 degraded 2-sec-butylphenol through 3-sec-butylcatechol along a meta-cleavage pathway. Degradation experiments with various alkylphenols showed that the degradability of alkylphenols by strain MS-1 depended strongly on the position (ortho ≫ meta = para) of the alkyl substitute, and that strain MS-1 could degrade 2-alkylphenols with various sized and branched alkyl chain (o-cresol, 2-ethylphenol, 2-n-propylphenol, 2-isopropylphenol, 2-sec-butylphenol, and 2-tert-butylphenol), as well as a dialkylphenol (namely, 6-tert-butyl-m-cresol)