Publications by authors named "Seiichiro Umemura"

Levoglucosan (LG) is an anhydrosugar produced through glucan pyrolysis and is widely found in nature. We previously isolated an LG-utilizing thermophile, Bacillus smithii S-2701M, and suggested that this bacterium may have a metabolic pathway from LG to glucose, initiated by LG dehydrogenase (LGDH). Here, we completely elucidated the metabolic pathway of LG involving three novel enzymes in addition to LGDH.

View Article and Find Full Text PDF

A series of multivalent sialoglyco-conjugated nanoparticles were efficiently synthesized by using highly-branched α-glucuronic acid-linked cyclic dextrins (GlcA-HBCD) as a backbone. The sialoglycoside-moieties, with varying degrees of substitution, could be incorporated onto the preformed nanoparticles. These synthesized particles, which are highly soluble in aqueous solution, were shown to have a spherical nanostructure with a diameter of approximately 15nm.

View Article and Find Full Text PDF

We designed and synthesized three tetravalent sialo-glycoclusters that had different separations between the terminal sialic acids and the linking carboxy groups of the ethylene glycol bis(β-aminoethyl ether)-N,N,N',N'-tetraacetate scaffold to serve as ligands for the sialic acid-binding lectin Sambucus sieboldiana agglutinin (SSA). The interaction between each glycocluster and SSA was characterized by hemagglutination inhibition, quantitative precipitation, and double-diffusion assays. For the precipitation assays, the precipitin curves indicated that the ligands and SSA bound in either a 1:1 or a 1:2 ratio, i.

View Article and Find Full Text PDF