| Budget Amount *help |
¥4,940,000 (Direct Cost: ¥3,800,000、Indirect Cost: ¥1,140,000)
Fiscal Year 2017: ¥1,040,000 (Direct Cost: ¥800,000、Indirect Cost: ¥240,000)
Fiscal Year 2016: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000)
Fiscal Year 2015: ¥2,340,000 (Direct Cost: ¥1,800,000、Indirect Cost: ¥540,000)
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| Outline of Final Research Achievements |
Beta-1,6-glucan, a cell wall component of fungi, is known as a bioactive (antitumor) polysaccharide. In this study, the cDNAs encoding Beta-1,6-glucan degrading enzymes (Beta-1,6-glucanases) were cloned from basidiomycetes, and two Beta-1,6-glucanases, Sc30 (from Schizophyllum commune) and Cc30 (from Coprinopsis cinerea), were heterologously expressed in Aspergillus oryzae. Sc30 (57 kDa) and Cc30 (50 kDa) catalyzed depolymerization of Beta-1,6-glucan endolytically, and were highly specific toward Beta-1,6-glucan polysaccharide. The enzymes were most active at pH 5.0. We prepared glycosynthase mutants using the Beta-1,6-glucanases, Sc30 and Cc30. Some prepared Beta-glucan oligosaccharides with various structures showed the immunostimulatory activity on murine macrophage-like cells. It was suggested that these functional oligomers were consisted of Beta-1,6-linkages, and their degree of polymerization were greater than five.
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| Academic Significance and Societal Importance of the Research Achievements |
きのこ類に含まれるβ-1,6グルカンは免疫活性化機能を持つ。しかしながら、きのこ類からの単離・精製は困難であるため、純粋なβ-1,6グルカンが得られた例はない。β-1,6グルカンは生物の中で真菌類のみが唯一所有する分子あり、ヒトはβ-1,6グルカンを真菌類を認識する際の目印としている可能性がある。近年、食用きのこの大量栽培が可能になってきたが、消費量は伸び悩んでいる。本研究によってβ-1,6グルカンを、免疫に関与する新しい機能性食物繊維として提唱できれば、きのこ類に新たな価値を生み出すことができ、きのこ産業の活性化に繋がる。
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