Publications by authors named "A Ishiwata"

Article Synopsis
  • Gum arabic is important in the food industry for its ability to stabilize and emulsify, and it also supports the growth of beneficial gut bacteria like Bifidobacterium.
  • The two types of gum arabic, Acacia senegal and A. seyal, both have a protein component called arabinogalactan protein (AGP), but they differ in their structure.
  • This research identifies a new enzyme that breaks down specific components of A. seyal gum, revealing its structure and showing how Bifidobacterium catenulatum can use these sugars for growth.
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We report the case of a 77-year-old Japanese woman with neuromyelitis optica spectrum disorder, treated with 15 mg of prednisolone daily, who presented with acute septic shock and altered consciousness due to Dolosigranulum pigrum bacteremia. Intravenous extracellular fluids and broad-spectrum antibiotics were administered as an initial treatment. However, the patient died shortly after admission.

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An efficient and versatile glycosylation methodology is crucial for the systematic synthesis of oligosaccharides and glycoconjugates. A direct intermolecular and an indirect intramolecular methodology have been developed, and the former can be applied to the synthesis of medium-to-long-chain glycans like that of nucleotides and peptides. The development of a generally applicable approach for the stereoselective construction of glycosidic bonds remains a major challenge, especially for the synthesis of 1,2- glycosides such as β-mannosides, β-L-rhamnosides, and β-D-arabinofuranosides with equatorial glycosidic bonds as well as α-D-glucosides with axial ones.

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The capsular polysaccharide (CPS) is a major virulence factor of the pathogenic and a promising target for vaccine development. However, the synthesis of the 1,2--2-amino-2-deoxyglycoside core of CPS remains challenging to date. Here we develop a highly α-selective ZnI-mediated 1,2- 2-azido-2-deoxy chemical glycosylation strategy using 2-azido-2-deoxy glucosyl donors equipped with various 4,6--tethered groups.

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β-N-Acetylgalactosamine-containing glycans play essential roles in several biological processes, including cell adhesion, signal transduction, and immune responses. β-N-Acetylgalactosaminidases hydrolyze β-N-acetylgalactosamine linkages of various glycoconjugates. However, their biological significance remains ambiguous, primarily because only one type of enzyme, exo-β-N-acetylgalactosaminidases that specifically act on β-N-acetylgalactosamine residues, has been documented to date.

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