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Published Papers 【 display / non-display 】

• The effect of Aspergillus luchuensis pectin methylesterase genes pmeA and pmeB on methanol production in sweet potato shochu.

  Mizutani O, Kakizono D, Takahashi T, Mukai N, Fukuda H, Yamada O

  Bioscience, biotechnology, and biochemistry ( Bioscience, Biotechnology and Biochemistry )  87 ( 7 ) 777 - 785   2023.06 [ Peer Review Accepted ]

  Type of publication: Research paper (scientific journal)

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• Preparation and Crystal Structure Analysis of High-Strength Film Derived from Nigeran Ester Derivatives

  Togo Azusa, Uechi Keiko, Mizutani Osamu, Kimura Satoshi, Iwata Tadahisa

  Journal of Fiber Science and Technology ( 一般社団法人 繊維学会 )  78 ( 8 ) 126 - 132   2022 [ Peer Review Accepted ]

  Type of publication: Research paper (scientific journal)

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  <p>Nigeran (<i>α</i>-1,3-<i>alt</i>-<i>α</i>-1,4-glucan) is a linear glucan with alternating <i>α</i>-1,3- and <i>α</i>-1,4-glycosidic linkages. It is extracted from the cell walls of certain species in the genera <i>Aspergillus</i> and <i>Penicillium</i>. Nigeran can be esterified and used as a film, but its strength is only approximately 4–25 MPa. However, in the present study, high-strength nigeran ester films with tensile strengths of 100 MPa were successfully prepared by thermally stretching and annealing the melt-quenched films. Two-dimensional wide-angle X-ray diffraction (2D-WAXD) analysis revealed that the highly oriented films of nigeran butyrate (NGBu), nigeran valerate (NGVa), and nigeran hexanoate (NGHx) studied herein had two-fold helix symmetry along the molecular axis. Assuming the crystal systems to be orthorhombic, the unit lattice of each ester was calculated as NGBu (<i>a</i>=28.6Å, <i>b</i>=9.07Å, <i>c</i>=16.5Å), NGVa (<i>a</i>=31.5Å, <i>b</i>=9.07Å, <i>c</i>=16.2Å), and NGHx (<i>a</i>=36.7Å, <i>b</i>=9.07Å, <i>c</i>=16.2Å). In the calculated unit lattice parameters, only the <i>a</i>-axis was extended as the number of ester carbons increased.</p>

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• Identification of Genes Involved in the Synthesis of the Fungal Cell Wall Component Nigeran and Regulation of Its Polymerization in Aspergillus <i>luchuensis</i>.

  Uechi K, Yaguchi H, Tokashiki J, Taira T, Mizutani O

  Applied and environmental microbiology   87 ( 21 ) e0114421   2021.10 [ Peer Review Accepted ]

  Type of publication: Research paper (scientific journal)

  　View Summary

  Certain Aspergillus and Penicillium spp. produce the fungal cell wall component nigeran, an unbranched D-glucan with alternating α-1,3- and α-1,4-glucoside linkages, under nitrogen starvation. The mechanism underlying nigeran biosynthesis and the physiological role of nigeran in fungal survival are not clear. We used RNA-seq to identify genes involved in nigeran synthesis in the filamentous fungus Aspergillus luchuensis when grown under nitrogen-free conditions. agsB, which encodes a putative α-1,3-glucan synthase, and two adjacent genes (agtC and gnsA) were upregulated under conditions of nitrogen starvation. Disruption of agsB in A. luchuensis (ΔagsB) resulted in the complete loss of nigeran synthesis. Furthermore, overexpression of agsB in an Aspergillus oryzae strain that cannot produce nigeran resulted in nigeran synthesis. These results indicated that agsB encodes a nigeran synthase. Therefore, we have renamed the A. luchuensis agsB as nigeran synthase gene (nisA). Nigeran synthesis in an agtC mutant (ΔagtC) increased to 121%; conversely, that in ΔgnsA and ΔagtCgnsA decreased to 64% and 63%, respectively, compared to that in the wild-type strain. Our results revealed that AgtC and GnsA play an important role in regulating not only the quantity of nigeran but also its polymerization. Collectively, our results demonstrated that nisA (agsB) is essential for nigeran synthesis in A. luchuensis, whereas agtC and gnsA contribute to the regulation of nigeran synthesis and its polymerization. This research provides insights into fungal cell wall biosynthesis, specifically the molecular evolution of fungal α-glucan synthase genes and the potential utilization of nigeran as a novel biopolymer. Importance The fungal cell wall is composed mainly of polysaccharides. Under nitrogen-free conditions, some Aspergillus and Penicillium spp. produce significant levels of nigeran, a fungal cell wall polysaccharide composed of alternating α-1,3-/1,4-glucosidic linkages. The mechanisms regulating the biosynthesis and function of nigeran are unknown. Here, we performed RNA sequencing of Aspergillus luchuensis cultured under nitrogen-free or low-nitrogen conditions. A putative α-1,3-glucan synthase gene, whose transcriptional level was upregulated under nitrogen-free conditions, was demonstrated to encode nigeran synthase. Furthermore, two genes encoding an α-glucanotransferase and a hypothetical protein were shown to be involved in controlling nigeran content and molecular weight. This study reveals genes involved in the synthesis of nigeran, a potential biopolymer, and provides a deeper understanding of fungal cell wall biosynthesis.

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• Expression profiles of amylolytic genes in AmyR and CreA transcription factor deletion mutants of the black koji mold Aspergillus luchuensis.

  Wataru Hashimoto, Hiraku Arai, Osamu Mizutani, Osamu Yamada, Takahiro Shintani, Katsuya Gomi

  Journal of bioscience and bioengineering   132 ( 4 ) 321 - 326   2021.06 [ Peer Review Accepted ]

  Type of publication: Research paper (scientific journal)

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• Development of an itraconazole resistance gene as a dominant selectable marker for transformation in Aspergillus oryzae and Aspergillus luchuensis.

  Tokashiki J, Toyama H, Mizutani O

  Bioscience, biotechnology, and biochemistry   85 ( 3 ) 722 - 727   2021.02 [ Peer Review Accepted ]

  Type of publication: Research paper (scientific journal)

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Books 【 display / non-display 】

Books 【 display / non-display 】

• Genome Engineering via CRISPR-Cas9 System 1st Edition

  Arazoe T., Mizutani O. ( Part: Multiple Authorship ,  5. Targeted genome editing using CRISPR-Cas9 system in fungi )

  Elsevier  2020.02

Other Papers 【 display / non-display 】

Other Papers 【 display / non-display 】

• Phenolic acid decarboxylase of <i>Aspergillus luchuensis</i> plays a crucial role in 4-vinylguaiacol production during <i>awamori</i> brewing

  Seibutsu-kogaku Kaishi ( The Society for Biotechnology, Japan )  100 ( 2 ) 79 - 79   2022.02

   

  DOI CiNii Research

Presentations 【 display / non-display 】

Presentations 【 display / non-display 】

• Expression profiles of amylolytic genes in the black koji-mold Aspergillus luchuensisAspergillus luchuensis

  Wataru Hashimoto, Hiraku Arai, Osamu Mizutani, Osamu Yamada, Takahiro Shintani, ○Katsuya Gomi

  15th European Conference on Fungal Genetics (ECFG15)　  (Italy ROME)  2020.02  -  2020.02 

• 麹菌の酸性プロテアーゼが芋焼酎の香気に与える影響

  瀬戸口翔, 水谷 治, 山田 修, 二神泰基, 岩井謙一, 高瀬良和, 玉置尚徳

  第 10 回国際酒文化・科学技術検討会  (鹿児島)  2018.10  -  2018.10 

• 沖縄の伝統的な蒸留酒、泡盛の製造に関与する微生物について

  外山博英, 水谷 治, 塚原正俊

  第 10 回国際酒文化・科学技術検討会  (鹿児島)  2018.10  -  2018.10 

• 麹菌 ligD 遺伝子がゲノム編集に起因する大規模欠失変異に与える影響

  上元 優, 林 梨咲, 渡嘉敷直杏, 荒添貴之, 山田 修, 外山博英, 水谷 治

  第３回ゲノム編集学会  (広島)  2018.06  -  2018.06 

• Microbes involved in brewing of Awamori, traditional distilled liquor in Okinawa

  Hirohide Toyama, Osamu Mizutani, Masatoshi Tsukahara

  VerVAAP2017 (“Fermentation Technology for Value Added Agricultural Products”)  (Thailand)  2017.07  -  2017.07 

Grant-in-Aid for Scientific Research 【 display / non-display 】

Grant-in-Aid for Scientific Research 【 display / non-display 】

• Grant-in-Aid for Scientific Research(C)

  Project Year: 2019.04  -  2022.03 

  Direct: 3,400,000 (YEN)  Overheads: 1,020,000 (YEN)  Total: 4,420,000 (YEN)

• Grant-in-Aid for Scientific Research(C)

  Project Year: 2016.04  -  2019.03 

  Direct: 3,800,000 (YEN)  Overheads: 1,140,000 (YEN)  Total: 4,940,000 (YEN)

• Grant-in-Aid for Young Scientists(B)

  Project Year: 2013.04  -  2016.03 

  Direct: 3,300,000 (YEN)  Overheads: 990,000 (YEN)  Total: 4,290,000 (YEN)