Kazukiyo Kobayashi

Nagoya University, Nagoya, Aichi, Japan

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Publications (155)334.69 Total impact

  • ChemInform 01/2010; 30(6).
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    ABSTRACT: ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
    ChemInform 01/2010; 33(1).
  • Advances in Science and Technology 01/2008; 57:166-169.
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    ABSTRACT: Glycopolymers carrying sulfated saccharides with modest sugar contents (11% and 28%) were found to suppress the formation of amyloid fibrils by amyloid beta peptides (Abeta(1-42), Abeta(1-40), and Abeta(25-35)), as evaluated by thioflavin T assays and atomic force microscopy observation. Circular dichroism spectra showed that the conformation of amyloid beta peptides depended on the glycopolymer additives, and that the glycopolymer additives reduced the beta-sheet contents. Neutralization activity was confirmed by in vitro assay with HeLa cells. The sulfate group and the appropriate sugar contents were essential for the inhibitory effect.
    Biomacromolecules 08/2007; 8(7):2129-34. · 5.37 Impact Factor
  • Yoshiko Miura, Daisuke Koketsu, Kazukiyo Kobayashi
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    ABSTRACT: A well-defined glycopolymer was synthesized to investigate its properties. The glycopolymer was obtained with a narrow polydispersity by nitroxide-mediated radical polymerization of styrene carrying acetylated lactose and by the subsequent deprotection. The cylindrical structure and helical conformation of the polymer were measured by circular dichroism (CD) spectra. The affinities of the polymers towards lectins depended on the degree of polymerization (DP), and the polymers with higher DP showed stronger affinity. Copyright © 2007 John Wiley & Sons, Ltd.
    Polymers for Advanced Technologies 07/2007; 18(8):647 - 651. · 1.64 Impact Factor
  • Biomacromolecules 03/2007; 8(2):753-6. · 5.37 Impact Factor
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    ABSTRACT: Shiga toxin (Stx) is one of the most critical factors in the development of hemolytic uremic syndrome and other systemic complications following enterohemorrhagic Escherichia coli (EHEC) infection. Substances neutralizing Stx by interfering with toxin-receptor binding have been explored as therapeutic candidates for EHEC infection. In this study, we examined globotriaosyl (Gb3), galabiosyl (Gb2) and galacto-trehalose, each of which was synthetically conjugated with a polyacrylamide backbone, for Stxneutralizing activity. Galacto-trehalose was designed as a Gb2 mimicking, unnatural Stx-ligand that was expected to show tolerance to enzymatic degradation in vivo. Galacto-trehalose copolymer showed neutralizing activity against Stx-1 but not Stx-2 in a HeLa cell cytotoxicity assay. It was thought that galactotrehalose copolymer could be a lead compound for the treatment of Stx-mediated diseases, although it requires modification to show neutralizing activity to Stx-2. The Gb3 copolymer with high sugar unit density showed stronger neutralizing activity against Stx-2 than those with lower density. However, the density-dependency of the neutralizing activity was less obvious against Stx-1. Intravenous administration of the Gb3 copolymer prevented death in mice lethally infected with Stx-1- and Stx-2-producing E. coli O157:H7. Thus, we demonstrated that the artificial Gb3 copolymer could neutralize Stx-1 and the more clinically relevant Stx-2 in vitro and effectively inhibit Stx toxicity in vivo.
    Microbiology and Immunology 02/2007; 51(6):581-92. · 1.55 Impact Factor
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    Masayuki Toyoshima, Ken Ooya, Yoshiko Miura, Kazukiyo Kobayashi
    Journal of the Japan Society of Powder and Powder Metallurgy 01/2007; 54(12):843-848.
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    ABSTRACT: A novel strategy to construct a fibroblast scaffold on substrates has been demonstrated via top-down photolithography and the subsequent bottom-up processes of molecular self-assembly and molecular recognition. 3-Aminopropyltrimethoxysilane (APS) self-assembled monolayer was micropatterned by photolithography. An anionic polysaccharide heparin was adsorbed selectively on the cationic APS region of the micropatterned substrate. Basic fibroblast growth factor (bFGF) was selectively bound to the displayed heparin region and then micropatterned cultivation of fibroblast cells was successful on the bFGF–heparin–APS substrate.
    Surface Science 01/2007; 601(18):3871-3875. · 1.87 Impact Factor
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    ABSTRACT: Polystyrene derivatives with lactose, glucose, maltose, maltotriose, maltopentaose, and maltoheptaose on each benzene ring were prepared by the radical polymerization of a new class of macromers synthesized by coupling the corresponding oligosaccharide lactones with p-vinylbenzylamine. These polymers consisting of amphiphilic structural units were water-soluble, and organic solutes were bound to hydrophobic microenvironments of the polymers in water. α-D-Glucopyranose-carrying polymers were recognized and precipitated by concanavalin A. Cultivation of liver cells (hepatocytes) was attempted using culture dishes whose surface was coated with lactose-, glucose-, maltose-, and maltotriose-carrying polystyrenes. It has been found that a lactose-carrying polystyrene (PVLA) is a useful surface material for hepatocyte culture. 1) Highly specific adhesion of hepatocytes was attained for PVLA-coated dishes with or without serum supplement. 2) The cell adhesion was a threshold phenomenon with respect to the PVLA concentration on the dish. 3) The cell adhesion was effectively inhibited when hepatocytes were treated with PVLA molecules in the medium prior to culture. 4) The adhesion was not inhibited by albumin, an adhesion-inhibitory protein in serum. These findings suggest that pendent galactose residues of a PLVA molecule functioned as a strong recognition determinant for hepatocytes. We assume that multi-antennary, high-density galactose residues of PVLA are attributed to the specific adhesion of hepatocytes.
    Journal of Macromolecular Science: Part A - Chemistry. 10/2006; 25(5):655-667.
  • Journal of Carbohydrate Chemistry 08/2006; 21(6)(601–607 (2002)):605-611. · 0.85 Impact Factor
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    ABSTRACT: A Gb3-trisaccharide mimic peptide was selected with biopanning from a phage display library against anti-Gb3 antibody to neutralize Shiga toxins (Stxs). Biopanning was carried out on a microplate immobilized with a Fab fragment of anti-Gb3 antibody and a subtraction procedure screening was applied to enhance specificity. The selected phage clones showed strong affinity to anti-Gb3 antibody and to Stxs. Among these clones, a 9-mer sequence WHWTWLSEY was determined as the strongest Gb3 mimic peptide and chemically synthesized. The peptide bound strongly to Stx-1 and Stx-2, though the binding was inhibited with Gb3Cer. Surface plasmon resonance (SPR) and fluorescent spectroscopy determined that the affinity of the peptide to both Stxs was strong. Neutralization activity was confirmed by in vitro assay with HeLa cells. The Gb3 mimic peptide potentially has great promise for use against Stxs.
    Biochimica et Biophysica Acta 07/2006; 1760(6):883-9. · 4.66 Impact Factor
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    ABSTRACT: Moraxella catarrhalis is one of the major pathogens of respiratory and middle ear infections. Attachment of this bacterium to the surface of human pharyngeal epithelial cells is the first step in the pathogenesis of infections. This study revealed that sulfatide might act as a binding molecule for the attachment of M. catarrhalis to human pharyngeal epithelial cells. Furthermore, six different synthetic sulfatides were found to inhibit the attachment of M. catarrhalis significantly at an optimum concentration of 10 microg/ml. Synthetic sulfatides may have the potential to be used as a therapy to prevent M. catarrhalis infections.
    Microbiology and Immunology 02/2006; 50(12):967-70. · 1.55 Impact Factor
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    ABSTRACT: We have designed novel short peptides expressing both antimicrobial and Shiga-toxin (Stx) neutralization activities by combining nuclear localization signal (NLS) peptides (RIRKKLR, PKKKRKV, and PRRRK) tandemly with globotriaoside (Gb3) mimic peptide (WHWTWL). These fusion peptides exhibited excellent antimicrobial activity against both gram-positive and gram-negative bacteria. A peptide WHWTWLRIRKKLR (Trp-His-Trp-Thr-Trp-Leu-Arg-Ile-Arg-Lys-Lys-Leu-Arg), especially, exhibited about 100 times higher activity than the original NLS peptide. SPR analysis demonstrated that the binding of this peptide to both Stxs was strong: K(d) = 6.6 x 10(-6) to Stx-1 and 6.8 x 10(-6) to Stx-2. The in vitro assay against Stx-1 using HeLa cells showed that this peptide increased the survival rate of HeLa cells against the infection of Stx-1. The peptide has been found to maintain high antimicrobial activity, Stx neutralization activity, and no cytotoxicity at its concentration of 7.8-31.3 microg/mL (4.2-16.7 microM). The present peptide design has a prospect of developing potent multifunctional drugs to destroy proteinaceous toxin-producing bacteria and to simultaneously neutralize the toxins released by bacteriolysis.
    Bioorganic & Medicinal Chemistry 02/2006; 14(1):77-82. · 2.90 Impact Factor
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    ABSTRACT: Efficient matrix that resists the nonspecific adsorption of proteins from the contacting phosphate buffer silane (PBS) solution has been explored to fabricate carbohydrate arrays on silicon wafer. p-Vinylbenzyllactonoamide (VLA) was immobilized onto silicon through Si–C bond. The VLA-covered substrate was then photolithographically micropatterned through a photomask by ultraviolet (UV) irradiation. The VLA-covered regions recognized specifically the lactose-binding lectin in PBS solution. On the other hand, the UV-irradiated regions, i.e., SiOx surface, prevented the nonspecific adsorption of the lectin from the contacting PBS solution. Several control experiments have demonstrated that the resistant-ability of SiOx surface as the matrix was comparable to the best of known system for resisting the nonspecific adsorption.
    Thin Solid Films 01/2006; 499(1):213-218. · 1.87 Impact Factor
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    ABSTRACT: Divergent pathways are disclosed in the activation of 2-O-benzyl-1-hydroxy sugars by a reagent combination of CBr4 and Ph3P, all of which afford one-pot alpha-glycosylation methods. When this reagent is used in CH2Cl2, the 1-hydroxy sugar is converted to the alpha-glycosyl bromide in a conventional way and leads to the one-pot alpha-glycosylation method based on a halide ion-catalytic mechanism. In either DMF or a mixture of DMF and CHCl3, however, alternative alpha-glycosyl species are generated. From the 1H and 13C NMR study of the products, as well as the reactions using Vilsmeier reagents [(CH3)2N+=CHX]X- (X=Br and Cl), these were identified as cationic alpha-glycopyranosyl imidates having either Br- or Cl- counter ion. The cationic alpha-glycosyl imidate (Br-), derived specifically in the presence of DMF, is more reactive than the alpha-glycosyl bromide and thus is responsible for the accelerated one-pot alpha-glycosylation. The one-pot alpha-glycosylation methodology performed in DMF was assessed also with different types of acceptor substrates including tertiary alcohols and an anomeric mixture of 1-OH sugars.
    Carbohydrate Research 11/2005; 340(14):2236-44. · 2.04 Impact Factor
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    ABSTRACT: The bis(alpha-D-mannopyranosyl)-[60]fullerene conjugate 3 was prepared by thermal coupling of C60 and either 2-azidoethyl 2,3,4,6-tetra-O-acetyl- or 2,3;4,6-di-O-isopropylidene-alpha-D-mannopyranoside (Scheme). Compound 3 was found to readily self-assemble. Dynamic-light-scattering (DLS) and atomic-force microscopy (AFM) experiments supported that the amphiphilic compound gives rise to nano-sized supramolecular structures during sugar deprotection (Ac-group removal) performed in MeOH/CH2Cl2 solution. Encapsulation studies with an aqueous suspension of 3 showed that the self-assembling structure envelopes Ba2+ and the fluorescent dye Acridine Red during its formation, which indicates that it resembles a bilayer vesicle or an unadulterated liposome with an inner hollow space. In addition to this notable property, the unique molecular geometry of the spatially arranged mannosyl surface residues of 3 gives rise to strong binding of the carbohydrate-recognizing lectin Con A. Hence, the polar amphiphilic end of 3 mimics the structure of 3,6-branched tri-alpha-D-mannoside (6; Fig. 3), a natural ligand of the Con A protein.
    Chemistry & Biodiversity 10/2005; 2(9):1232-41. · 1.81 Impact Factor
  • Isao Wataoka, Kazukiyo Kobayashi, Kanji Kajiwara
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    ABSTRACT: An oligomaltose-carrying polystyrene "glycoconjugate polystyrene" was synthesized by the homopolymerization of 4-vinylbenzylamine oligomaltonic amides, derived from maltose, maltotriose, maltopentaose, and maltoheptaose. The resultant amphiphilic glycoconjugate polystyrenes were dissolved in 0.1 M aqueous urea, and their structures characterized by small-angle X-ray scattering and molecular modeling. "Glycoconjugate polystyrene" was found to behave as a "molecular bottle brush", composed of a large pseudo-helical polystyrene backbone and carbohydrate brushes. A large pseudo-helical polystyrene backbone is formed by a random sequence of TT, TG, and/or TTGG. The results indicate that the cross-section of a backbone chain with smaller oligosaccharide side-chains is obliged to expand more than that with longer side-chains. Even with rigid hydrophilic pendant oligosaccharide chains, the larger pseudo-helix of the main chain could orient the side-chains so as to envelop the hydrophobic backbone in aqueous solution. Thus the conformation of the main chain is determined not only by the chemical nature of an oligosaccharide chain but also by its length.
    Carbohydrate Research 05/2005; 340(5):989-95. · 2.04 Impact Factor
  • Yoshinao Yamada, Kazunori Matsuura, Kazukiyo Kobayashi
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    ABSTRACT: We describe herein the construction of periodically, spatially controlled glycoclusters along DNA duplexes and their cooperative lectin recognition. Site-specifically alpha-mannosylated oligodeoxynucleotide 20-mer (Man-ODN20) was synthesized via the phosphoramidite solid-phase synthesis. Alternate hybridization of the Man-ODN20 with the half-sliding complementary ODN 20-mer (hscODN20) gave an alternately prolonged Man-cluster Man-ODN20/hscODN20. The binding of the Man-cluster to FITC-labeled ConA lectin showed sigmoidal fluorescence dependency on the concentration of Man-ODN, indicating that some mannose residues along the repeating DNA duplex were cooperatively bound to ConA (apparent affinity constant: K(af)=2.4 x 10(4)M(-1) and Hill coefficient: n=3.5). The duplex of Man-ODN20 with full complementary ODN 20-mer (fcODN20) was little bound to ConA. The binding behavior of Man-ODN20/hscODN20 is compared with that of the alternately prolonged Gal-cluster Gal-ODN20/hscODN20 previously reported. Duplexes 20-mer, 40-mer, and 60-mer presenting one, two, and three periodic galactoses were also prepared by full hybridization of 20-mer beta-galactosylated oligodeoxynucleotide (Gal-ODN20) with the periodically repeating full complementary 20-mer, 40-mer, and 60-mer ODNs. RCA(120) lectin was found to little bind the 20-mer and 40-mer duplexes and to bind weakly and non-cooperatively the 60-mer duplex (K(af)=1.1 x 10(4)M(-1)). The cooperative lectin recognition of these glycoclusters in relation with the degree of association (DA) of ODN and the numbers of glycosides along the DNA duplex is discussed.
    Bioorganic & Medicinal Chemistry 04/2005; 13(6):1913-22. · 2.90 Impact Factor
  • Kazunori Matsuura, Katsuhiro Hayashi, Kazukiyo Kobayashi
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    ABSTRACT: A novel strategy for artificial regulation system of gene expression applying the specific molecular recognition between carbohydrate and lectin is proposed. Plasmid-lactose conjugates (pActin-lactose and pGFP-lactose) prepared via diazocoupling maintained the transcription activity with T7 RNA polymerase. Gel-shift assay showed that the pActin-lactose conjugates were specifically complexed with galactose-specific lectin RCA(120) with a strong binding affinity (K(a) = 7.6 x 10(5) M(-1) per Lac-unit). The complexes were observed to form aggregates of sub-several micrometer size by means of transmission electron microscopy (TEM) and atomic force microscopy (AFM). The activities of transcription and expression of the conjugates were evaluated, respectively, on the basis of the amount of transcript of pActin and the fluorescent intensity of the expressed GFP. These activities were repressed in the presence of an increasing concentration of RCA120, and then recovered by adding lactose, lactosylceramide-containing liposomes, and lactose-carrying polymers to the conjugate-RCA120 complex. Gel-shift assay and TEM observation revealed that the aggregation form of the complex was relaxed partially in the presence of the lactose derivatives, which increased the accessibility of T7 RNA polymerase to result in the recovery of transcription activity.
    Biomacromolecules 01/2005; 6(5):2533-40. · 5.37 Impact Factor

Publication Stats

844 Citations
334.69 Total Impact Points

Institutions

  • 1969–2010
    • Nagoya University
      • • Graduate School of Engineering
      • • Department of Molecular Design and Engineering
      Nagoya, Aichi, Japan
  • 2005
    • Shinshu University
      • Faculty of Textile Science and Technology
      Matsumoto, Nagano-ken, Japan
  • 2004
    • Kyushu University
      • Department of Chemistry
      Fukuoka-shi, Fukuoka-ken, Japan
  • 2002–2004
    • National Institute of Advanced Industrial Science and Technology
      Tsukuba, Ibaraki, Japan
  • 2003
    • Shizuoka University
      • Department of Applied Chemistry and Biochemical Engineering
      Shizuoka-shi, Shizuoka-ken, Japan
    • State University of New York College of Environmental Science and Forestry
      • Department of Chemistry
      Syracuse, NY, United States
  • 1966–2003
    • Osaka University
      Suika, Ōsaka, Japan
  • 1992
    • Kanagawa Academy of Science and Technology
      Kawasaki Si, Kanagawa, Japan