Osaka University , or Handai , is a national university located in Osaka, Japan. It is the sixth oldest university in Japan as the Osaka Prefectural Medical College, and one of Japan's National Seven Universities. Numerous prominent scientists have worked at Osaka University such as the Nobel Laureate in Physics Hideki Yukawa. Wikipedia.
Saitoh T.,Osaka University
Cell host & microbe | Year: 2012
Neutrophils contribute to pathogen clearance by producing neutrophil extracellular traps (NETs), which are genomic DNA-based net-like structures that capture bacteria and fungi. Although NETs also express antiviral factors, such as myeloperoxidase and α-defensin, the involvement of NETs in antiviral responses remains unclear. We show that NETs capture human immunodeficiency virus (HIV)-1 and promote HIV-1 elimination through myeloperoxidase and α-defensin. Neutrophils detect HIV-1 by Toll-like receptors (TLRs) TLR7 and TLR8, which recognize viral nucleic acids. Engagement of TLR7 and TLR8 induces the generation of reactive oxygen species that trigger NET formation, leading to NET-dependent HIV-1 elimination. However, HIV-1 counteracts this response by inducing C-type lectin CD209-dependent production of interleukin (IL)-10 by dendritic cells to inhibit NET formation. IL-10 suppresses the reactive oxygen species-dependent generation of NETs induced upon TLR7 and TLR8 engagement, resulting in disrupted NET-dependent HIV-1 elimination. Therefore, NET formation is an antiviral response that is counteracted by HIV-1. Copyright © 2012 Elsevier Inc. All rights reserved.
Minamino T.,Osaka University
Biochimica et Biophysica Acta - Molecular Cell Research | Year: 2014
For construction of the bacterial flagellum, which is responsible for bacterial motility, the flagellar type III export apparatus utilizes both ATP and proton motive force across the cytoplasmic membrane and exports flagellar proteins from the cytoplasm to the distal end of the nascent structure. The export apparatus consists of a membrane-embedded export gate made of FlhA, FlhB, FliO, FliP, FliQ, and FliR and a water-soluble ATPase ring complex consisting of FliH, FliI, and FliJ. FlgN, FliS, and FliT act as substrate-specific chaperones that do not only protect their cognate substrates from degradation and aggregation in the cytoplasm but also efficiently transfer the substrates to the export apparatus. The ATPase ring complex facilitates the initial entry of the substrates into the narrow pore of the export gate. The export gate by itself is a proton-protein antiporter that uses the two components of proton motive force, the electric potential difference and the proton concentration difference, for different steps of the export process. A specific interaction of FlhA with FliJ located in the center of the ATPase ring complex allows the export gate to efficiently use proton motive force to drive protein export. The ATPase ring complex couples ATP binding and hydrolysis to its assembly-disassembly cycle for rapid and efficient protein export cycle. This article is part of a Special Issue entitled: Protein trafficking and secretion in bacteria. Guest Editors: Anastassios Economou and Ross Dalbey. © 2013 Elsevier B.V.
Kimura T.,Osaka University
Annual Review of Condensed Matter Physics | Year: 2012
Magnetoelectric (ME) multiferroics are materials that combine coupled electric and magnetic dipoles. Studies of ME multiferroics are a time-honored research subject because of their potential for future electronic devices. Recent discoveries have revealed that ferroelectricity can be induced by complex internal arrangements of magnetic moments. This new family of multiferroics is called magnetically induced ferroelectrics. Magnetically induced ferroelectrics are known to show giant ME effects, i.e., changes in ferroelectric polarization upon application of an external magnetic field. However, their ME effects usually occur at temperatures that are too low and at applied external fields (> ∼0.1 T) that are too high to be of practical use. Thus, the quest for a robust room-temperature ME effect is a major challenge in ME research. Lately, some ferrites with hexagonal crystal structures, termed hexaferrites, have been found to show ME effects at room temperature and low magnetic fields (∼0.01 T). The results represented an important step toward practical applications using the ME effect in magnetically induced ferroelectrics. This review introduces structure, magnetism, and resulting magnetoelectricity of hexaferrite systems, which are promising candidate materials for ME devices. Copyright © 2012 by Annual Reviews. All rights reserved.
Suzuki T.,Osaka University
Chemical Reviews | Year: 2011
The progress made in the area of iridium-catalyzed oxidation is discussed. Gelman reported the oxidation of secondary alcohols using an air-stable Ir pincer complex and Jensen developed a dihydride iridium PCP pincer complex and applied it to the oxidation of phenylethanol in the presence of tert-butylethylene as an oxidant. Lin reported the oxidative lactonization of 1,4- and 1,5-diols using IrH5(P-iPr3)2 with acetone as the oxidant. Suzuki reported a mild Tishchenko-type reaction using an iridium aminoalkoxide catalyst and Williams reported the one-pot synthesis of amides from alcohols. Williams reported that N-alkylation of phenylethylamine and tryptamine with alcohols proceeds with the [Ir(cod)Cl]2-dppf catalyst system. Ishii reported the synthesis of quinolines and pyroles from aminoalcohols and ketones in the presence of several iridium catalyst systems and KOH without any solvent.
Maeda N.,Osaka University
Molecular Aspects of Medicine | Year: 2012
The discovery of water channel protein (aquaporin [AQP]) has made a great impact on life sciences. So far, 13 AQPs have been identified in human. AQP3, 7, 9, and 10 are subcategorized as aquaglyceroporins which permeabilize glycerol as well as water. Many investigators have demonstrated that AQPs play a crucial role in the maintenance of water homeostasis, but the physiological significance of some AQPs as glycerol channels remains elusive. Adipocyte is a major source of glycerol, which is one of the substrates for hepatic gluconeogenesis. This review focuses on recent studies on glycerol metabolism through AQP7 and AQP9, and briefly discusses the importance of glycerol channel in adipocytes, liver, and heart. © 2012 Elsevier Ltd. All rights reserved.