Suguru Okuda

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Extensive evidence from rat and human studies indicates that glucocorticoid hormones influence cognitive performance. Posttraining activation of glucocorticoid-sensitive pathways dose-dependently enhances the consolidation of long-term memory. Glucocorticoid effects on memory consolidation rely on noradrenergic activation of the basolateral amygdala and(More)
In this article we summarize a wide variety of properties of arachidonic acid (AA) in the mammalian nervous system especially in the brain. AA serves as a biologically-active signaling molecule as well as an important component of membrane lipids. Esterified AA is liberated from the membrane by phospholipase activity which is stimulated by various signals(More)
Bacterial lipoproteins are synthesized as precursors in the cytoplasm and processed into mature forms on the cytoplasmic membrane. A lipid moiety attached to the N terminus anchors these proteins to the membrane surface. Many bacteria are predicted to express more than 100 lipoproteins, which play diverse functions on the cell surface. The Lol system,(More)
3-Hydroxykynurenine (3-HK) is a potential endogenous neurotoxin whose increased levels have been described in several neurodegenerative disorders. Here, we characterized in vitro neurotoxicity of 3-HK. Of the tested kynurenine pathway metabolites, only 3-HK, and to a lesser extent 3-hydroxyanthranilic acid, were toxic to primary cultured striatal neurons.(More)
3-Hydroxykynurenine (3-HK) is a tryptophan metabolite whose level in the brain is markedly elevated under several pathological conditions, including Huntington disease and human immunodeficiency virus infection. Here we demonstrate that micromolar concentrations (1-100 microM) of 3-HK cause cell death in primary neuronal cultures prepared from rat striatum.(More)
Gram-negative bacteria are impervious to many drugs and environmental stresses because they possess an outer membrane (OM) containing lipopolysaccharide (LPS). LPS is biosynthesized at the cytoplasmic (inner) membrane and is transported to the OM by an unknown mechanism involving the LPS transport proteins, LptA-G. These proteins have been proposed to form(More)
Millions of molecules of lipopolysaccharide (LPS) must be assembled on the Escherichia coli cell surface each time the cell divides. The biogenesis of LPS requires seven essential lipopolysaccharide transport (Lpt) proteins to move LPS from the inner membrane through the periplasm to the cell surface. However, no intermediate transport states have been(More)
Outer membrane-specific lipoproteins in Escherichia coli are released from the inner membrane by an ATP-binding cassette transporter, the LolCDE complex, which causes the formation of a soluble complex with a periplasmic molecular chaperone, LolA. LolA then transports lipoproteins to the outer membrane where an outer membrane receptor, LolB, incorporates(More)
An unknown amino sugar, U-7, which had been detected in the hydrolysate of the polysaccharide fraction (F-A) of Pseudomonas aeruginosa P14 lipopolysaccharide, was isolated from the hydrolysate of whole cells of this micro-organism and converted into the N-acetyl derivative (U-7NAc). On the basis of i.r.-absorption spectrometry, 13C-n.m.r. and 1H-n.m.r.(More)
Arachidonic acid (20:4) is a component of membrane lipids that has been implicated as a messenger both in physiological and pathophysiological processes, including ischemic injury and synaptic plasticity. In order to clarify direct trophic or toxic effects of arachidonic acid on central neurons, primary cultures of rat hippocampal neurons were exposed to(More)