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Last Updated :2024/11/16

研究者情報

マスター

アカウント（マスター）

  • 氏名

    都木　靖彰(タカギ　ヤスアキ), タカギ　ヤスアキ

所属（マスター）

  • 水産科学研究院　海洋応用生命科学部門　増殖生物学分野

所属（マスター）

  • 水産科学研究院　海洋応用生命科学部門　増殖生物学分野

独自項目

syllabus

  • 2021, 大学院共通授業科目（教育プログラム）：PARE, Inter-Graduate School Classes(Educational Program):PARE, 修士課程, 大学院共通科目, populations, human activities, environments, resources, food, land, rivers, coasts, atmosphere, soil, water, groundwater, geo-environment, water cycle, element cycles, ecosystems, poverty, sustainability, climate change, erosion, chemical substances, pollution, risk management, green technology
  • 2021, Introduction to Fisheries Sciences Ⅰ（水産科学汎論Ⅰ）, Introduction to Fisheries Sciences Ⅰ, 修士課程, 水産科学院, 水産科学，海洋生物学，生物多様性，生物資源, 環境, 資源探査, 漁業技術, 持続可能性, 環境保全, 養殖, 遺伝学, 生命工学, 微生物学, 化学，食糧科学,生物安全性
  • 2021, 増殖生物学特論Ⅰ, Advanced Aquaculture Biology Ⅰ, 修士課程, 水産科学院, 増殖、養殖、生理学、生化学、分子生物学、魚類、ウニ類
  • 2021, 増殖生物学特論Ⅱ, Advanced Aquaculture Biology Ⅱ, 修士課程, 水産科学院, 日本語：増殖、養殖、生理学、生化学、分子生物学、魚類、ウニ類
  • 2021, 環境と人間, Environment and People, 学士課程, 全学教育, 食のバリューチェーン、Society 5.0、エネルギー、異分野融合、持続可能性、フィールド、ロバストネス（強靱性）
  • 2021, 水産科学英語Ⅰ, English for Fisheries Sciences I, 学士課程, 水産学部, 水産生命科学英語、水産技術英語
  • 2021, 環境と人間, Environment and People, 学士課程, 全学教育, 海、河川、生命、細胞、遺伝子、魚、海藻、微生物、代謝、進化
  • 2021, 水族生理学, Physiology of Aquatic Animals, 学士課程, 水産学部, 無脊椎動物の消化，呼吸，循環，神経，内分泌，魚類の筋肉と筋細胞，魚類における筋細胞分化
  • 2021, 水産増殖学, General Aquaculture, 学士課程, 水産学部, 水産増殖，水産養殖，種苗生産，染色体地図，遺伝的多様性，遺伝マーカー，育種，遺伝的管理，魚病，海藻

PositionHistory

  • 教育研究評議会評議員, 2018年4月1日, 2020年3月31日
  • 教育研究評議会評議員, 2020年4月1日, 2022年3月31日
  • 教育研究評議会評議員, 2022年4月1日, 2024年3月31日
  • 水産学部長, 2022年4月1日, 2024年3月31日
  • 大学院水産科学院長, 2022年4月1日, 2024年3月31日
  • 大学院水産科学研究院長, 2022年4月1日, 2024年3月31日

researchmap

プロフィール情報

学位

  • 水産学博士（北海道大学）

プロフィール情報

  • 姓

    都木, タカギ

  • 名

    靖彰, ヤスアキ

  • ID各種

    200901028361363949

業績リスト

研究キーワード

  • 創傷治癒   化粧品   コンドロイチン硫酸   コラーゲンペプチド   再生医療用材料   細胞外基質   コラーゲン   魚類生理学   Fish Physiology   

研究分野

  • ライフサイエンス / 水圏生命科学 / コラーゲン ペプチド コンドロイチン硫酸 加水分解物
  • ライフサイエンス / 水圏生産科学 / チョウザメ 養殖 キャビア 地域振興 産学官連携
  • ライフサイエンス / 細胞生物学 / 細胞外基質 細胞活性制御
  • ナノテク・材料 / 有機機能材料 / コラーゲン 細胞足場 組織工学 再生医療

経歴

  • 2002年 - 2005年 北海道大学教授（大学院水産科学研究科） 教授
  • 2002年 - 2005年 Professor,Professor, Hokkaido University, Graduate School of Fisheries Sciences

学歴

  •         - 1990年   北海道大学   水産学研究科   水産増殖学専攻
  •         - 1990年   北海道大学

委員歴

  • 2024年02月 - 現在   日本水産学会   理事
  • 2022年03月 - 現在   日本水産学会   北海道支部支部幹事
  • 2019年02月 - 現在   日本水産学会   国際交流委員会
  • 2013年 - 現在   日本水産学会   水産増殖懇話会委員会
  • 2023年03月 - 2025年02月   日本水産学会   学会賞選考委員会
  • 2021年04月 - 2024年03月   日本水産増殖学会   会長

受賞

  • 1998年 1998: Best Oral Presentation Award, 2nd International Symposium on Fish Otolith Research and Application

論文

  • Qi Zhang, Shufang Hou, Yanmei Liu, Jia Du, Yongkang Jia, Qiushi Yang, Tingting Xu, Yasuaki Takagi, Dapeng Li, Xi Zhang
    Foods 13 18 2901 - 2901 2024年09月13日 [査読有り][通常論文]
     
    The southern catfish (Silurus meridionalis) is an economically important carnivorous freshwater fish in China. In this study, we compared the properties of skin collagen from southern catfish fed with raw food (RF) and cooked food (CF). The skin collagen yield in the RF group (8.66 ± 0.11%) was significantly higher than that of the CF group (8.00 ± 0.27%). SDS-PAGE, circular dichroism spectroscopy, and FTIR analyses revealed that the collagen extracted from southern catfish skin in both groups was type I collagen, with a unique triple helix structure and high purity. The thermal denaturation temperature of collagen in the RF group (35.20 ± 0.11 °C) was significantly higher than that of the CF group (34.51 ± 0.25 °C). The DPPH free radical scavenging rates were 68.30 ± 2.41% in the RF collagen and 61.78 ± 3.91% in the CF collagen, which was higher than that found in most fish collagen. Both the RF and CF groups had high ability to form fibrils in vitro. Under the same conditions, the CF group exhibited faster fibril formation and a thicker fibril diameter (p < 0.05). In addition, the RF group exhibited significantly higher expression of col1a1 compared to the CF group. These results indicated that feeding southern catfish raw food contributed to collagen production, and the collagen from these fish may have potential in biomaterial applications.
  • Shuichiro Watanabe, Ken Matsuzaki, Utano Shimizu, Ichiro Higuchi, Takashi Todo, Yasuaki Takagi, Kazuhiro Ura
    Fisheries Science 90 6 907 - 924 2024年06月10日 [査読有り][通常論文]
  • Md Rashidul Islam, Shunji Yunoki, Kazuhiro Ura, Yasuaki Takagi
    Sustainable Chemistry and Pharmacy 39 101612  2024年06月 [査読有り][通常論文]
  • Linyan Shi, Kazuhiro Ura, Yasuaki Takagi
    Osteoarthritis and Cartilage Open 6 2 100450 - 100450 2024年06月 [査読有り]
  • Yongkang Jia, Jia Du, Rujuan Xi, Qi Zhang, Li Li, Dapeng Li, Yasuaki Takagi, Xi Zhang
    Journal of Animal Science 102 2024年01月03日 [査読有り][通常論文]
     
    Abstract Grass carp (Ctenopharyngodon idellus) is an economically important farmed fish. This experiment was conducted to study the effects of different culture salinities on the growth and muscle quality of grass carp. We found that salinity of 0 to 5 had no significant effect on the growth of grass carp, but it significantly decreased at salinities above 5. Compared to salinity 0, the protein content of serum was significantly higher at salinities of 3 and 5. However, all serum biochemical compound measured, except glucose and total protein, decreased significantly at salinity 9. Muscle textural properties of grass carp were significantly higher at salinities of 3 and 5 than at 0, 7, and 9. Salinities of 0 to 3 had no significant effect on muscle nutrition of grass carp, but this parameter tended to decrease at salinities above 7. Salinities of 3 and 5 significantly favored muscle growth and expression of collagen-related genes, whereas the opposite was true for salinities of 7 and 9. These results indicated that grass carp grew normally at salinities of 3 and 5, with some improvement in muscle quality, whereas salinities of 7 and 9 had a negative effect on growth and quality. Therefore, appropriate salinity levels can help to improve the muscle quality of grass carp without affecting their growth.
  • Dawei Meng, Yasuaki Takagi
    Sustainable Chemistry and Pharmacy 36 101299 - 101299 2023年12月 [査読有り]
  • Naoya Terauchi, Dawei Meng, Wen Li, Haruto Inada, Kazuhiro Ura, Yasuaki Takagi
    Fisheries Science 89 4 527 - 535 2023年05月12日 [査読有り]
  • Md Rashidul Islam, Wen Li, Yumi Ogata, Takeya Yoshioka, Kazuhiro Ura, Takagi Yasuaki
    Sustainable Chemistry and Pharmacy 31 100944 - 100944 2023年04月 [査読有り][通常論文]
  • Boxue Yang, Wenzhao Li, Asuka Ishii, Ga-hyun Joe, Yutaka Shimizu, Yasuaki Takagi, Hiroki Saeki
    Waste and Biomass Valorization 2023年03月24日
  • Dawei Meng, Wen Li, Xiaoqian Leng, Yasuaki Takagi, Zhiyuan Dai, Hao Du, Qiwei Wei
    Process Biochemistry 124 180 - 188 2023年01月 [査読有り][通常論文]
  • Dawei Meng, Xiaoqian Leng, Yan Zhang, Jiang Luo, Hao Du, Yasuaki Takagi, Zhiyuan Dai, Qiwei Wei
    Carbohydrate Research 522 108685 - 108685 2022年12月 [査読有り][通常論文]
  • Wen Li, Kazuhiro Ura, Yasuaki Takagi
    Current Research in Food Science 5 698 - 709 2022年04月 [査読有り]
  • Tomoharu Yuhi, Osamu Nishimiya, Kaoru Ohno, Asami Takita, Takako Inoguchi, Kazuhiro Ura, Yasuaki Takagi
    Fisheries Science 88 2 259 - 273 2022年03月 [査読有り][通常論文]
     
    Accumulation of yolk precursor protein in the oviparous egg is essential for embryo growth. Transferrin-like protein, also known as major yolk protein, is a major precursor protein in sea urchins and sea cucumbers. In sea urchins, a new yolk protein was recently detected in Strongylocentrotus intermedius and Mesocentrotus nudus eggs. This protein, tentatively named yolk-related protein (YRP), was thought to have important physiological functions for sea urchin gonadal growth and gametogenesis. To understand the relationship between YRP and vitellogenesis, we investigated the molecular structure of sea urchin YRP, quantified the transcript levels during oogenesis, and identified the presence of YRP in coelomic fluid. Using molecular cloning, we characterized one cDNA that encoded YRP (mn-yrp). Structural analysis revealed that mn-YRP is an apolipoprotein B (ApoB)-like protein that belongs to the large lipid transfer protein superfamily. Quantification of mn-yrp (mn-apob) transcripts showed that mn-apob is mainly expressed in the stomach during gonadal growth. Immunobiochemical methods using antiserum revealed that mn-ApoB was present in the coelomic fluid. These results indicate that ApoB has a role in the transport of nutrients, such as sugar, lipids, and carotenoids, from the digestive tract to eggs via coelomic fluid in sea urchin.
  • Preparation of collagen nanofibril-scaffold from the skin of catfish (Pangasianodon hypophthalmus) farmed in the Mekong Delta.
    Ho QP, Thi MTL, Huynh LH, Tran MP, Thi BTN, Takagi Y
    AACL Bioflux 124 180 - 188 2022年 [査読有り][通常論文]
  • Wen Li, Naoya Terauchi, Dawei Meng, Nobuyuki Miyamoto, Naonobu Tsutsumi, Kazuhiro Ura, Yasuaki Takagi
    Sustainable Chemistry and Pharmacy 23 100499 - 100499 2021年10月 [査読有り][通常論文]
  • Quoc Phong Ho, Takagi Yasuaki, Lien Huong Huynh, Thanh Tuyen Nguyen, Minh Phu Tran, Thi Minh Thuy Le, Luu Ngoc Hanh Cao
    Can Tho University Journal of Science 13 Aquaculture 64 - 72 2021年06月30日 [査読有り][通常論文]
     
    This study was conducted to incorporate amine functional groups on the surface of hydroxyapatite to enhance its potential application in biomedical materials. Hydroxyapatite particles (HA) were synthesized from striped catfish (Pagasianodon hypophthalmus) bone and surface modified by grafting with (3-aminopropyl)triethoxysilane (APTES). Important factors affected grafting efficiency such as concentration of APTES, water content, reaction temperature and reaction time were studied. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM) were used to confirm the grafting reaction on HA surfaces. Grafting efficiency was evaluated based on intensity of characteristic absorption peaks of APTES. The experimental results showed that amine functional groups were successfully introduced on HA surface at optimal condition of 0.2 M APTES, 0.75 wt.% water content, at 60°C and 12-hour reaction time.
  • Thi Thanh Huong Do, Thi Kim Ha Nguyen, Tinh Em Nguyen, Minh Ky Tang, Takagi Yasuaki, Thanh Phuong Nguyen
    Can Tho University Journal of Science 13 Aquaculture 10 - 20 2021年06月30日 [査読有り][通常論文]
     
    The effects of temperature on growth performance, survival rate, digestive enzymatic activities, and physiological responses of striped snakehead (Channa striata) at fry stage were evaluated. The study consisted of two trials including (1) determination of temperature threshold and (2) effects of different temperatures (24°C, 27°C (control), 30°C, 33°C and 36°C) on growth performance, survival rate, digestive enzyme activities and physiological parameters of striped snakehead fry stage for 90 days. The growth experiment was conducted in 500-L tank (250-L water) with triplicates. The stocking density was 300 individuals per tank. Striped snakehead at fry stage showed a high tolerance to temperature ranging from 10 to 40ºC. After 90 days, fish reared in 30°C performed the greatest weight and survival rate (13.1±3.12 g/fish and 15.5±4.63%, respectively). The number of red blood cells and hemoglobin concentrations increased with the increase in temperature. It was discovered that different temperatures (from 27 to 36°C) did not significantly influence the number of white blood cells, osmolality, and ion concentration of fish. Glucose and cortisol concentrations increased with temperature rises and peaked in fish reared at 36°C, while temperatures of 30oC and 33oC showed higher digestive enzyme activities. It proves that 30°C is the optimal level for striped snakehead fry rearing.
  • Hồ Quốc Phong, Ngọc Gia Ngân Võ, Huỳnh Liên Hương, Takagi Yasuaki, Lê Thị Minh Thủy, Nguyễn Việt Bách
    Can Tho University Journal of Science 57 3 1 - 9 2021年06月30日 [査読有り][通常論文]
     
    Nghiên cứu được tiến hành nhằm gắn kết collagen trích ly từ da cá tra (Pangasiidae) lên bề mặt hydroxyapatite (HA) tổng hợp từ xương cá tra làm tăng khả năng ứng dụng trong lĩnh vực y sinh. Sau khi trích ly, collagen được gắn kết lên bề mặt HA thông qua cầu nối glutaraldehyde. Các hạt HA trước tiên gắn kết với 3 – amino propyl triethoxysilane (APTES) tạo nhóm chức amine trên bề mặt. Glutaraldehyde là cầu nối gắn kết HA và collagen thông qua phản ứng giữa nhóm chức amine và aldehyde. Các yếu tố ảnh đến sự gắn kết như nồng độ collagen, pH dung dịch phản ứng, thời gian và nhiệt độ của phản ứng được tiến hành khảo sát. Kết quả thí nghiệm cho thấy nồng độ collagen 1 mg/mL, dung dịch acetic acid hòa tan collagen có pH 3, thời gian phản ứng 3 giờ và nhiệt độ phản ứng 37C là điều kiện thích hợp để tiến hành gắn kết. Ngoài ra, kết quả chụp SEM cho thấy rằng các hạt HA được chế tạo có kích thước khoảng 1.000 nm và bị phủ một lớp collagen sau khi gắn kết.
  • Wen Li, Taishi Kobayashi, DaWei Meng, Nobuyuki Miyamoto, Naonobu Tsutsumi, Kazuhiro Ura, Yasuaki Takagi
    Food Bioscience 41 100991 - 100991 2021年06月 [査読有り][通常論文]
  • Md. Rashidul Islam, Tomoharu Yuhi, Dawei Meng, Takeya Yoshioka, Yumi Ogata, Kazuhiro Ura, Yasuaki Takagi
    LWT-Food Science and Technology 142 110944 - 110944 2021年05月 [査読有り][通常論文]
  • Xi Zhang, Huiyan Zhang, Shigeru Toriumi, Kazuhiro Ura, Yasuaki Takagi
    Aquaculture 529 735641 - 735641 2020年12月 [査読有り][通常論文]
  • Md. Rashidul Islam, Tomoharu Yuhi, Kazuhiro Ura, Yasuaki Takagi
    Applied Sciences 10 19 6660 - 6660 2020年09月23日 [査読有り][通常論文]
     
    To develop a new method for extracting gelatin from the sturgeon head, the conditions for pretreatment and extraction were optimized. Treatment at 65 °C (3–3.5 h) was enough to separate the head into mixed tissues (skin, scales, pectoral fins, muscle, bones, gills, and small cartilage pieces), skull cartilage, and liquid. From the intensities of α-, β- and γ-bands and yields, the optimized pretreatment conditions for type A and type B gelatin were 0.05 M HCl (1 h) and 0.1 M NaOH (1 h), respectively. The best extraction conditions were: (1) for type A gelatin: with distilled water (DW) (w/v 1:5) at 35 °C, pH 7 when stirring at 200 rpm for 3 h, and (2) for type B gelatin: with DW (w/v 1:5) at 50 °C, pH 8 when stirring at 200 rpm for 1 h. After the decalcification of extracted residues with 0.05 M HCl for 3 h, re-extraction of gelatin was possible. Under the best extraction conditions, yields of type A and B gelatins were 5.01 and 7.25% (dry gelatin weight/wet sample weight), respectively. Thus, it is possible to extract an industrial amount of gelatin from sturgeon heads, making them valuable by-products.
  • Dawei Meng, Wen Li, Kazuhiro Ura, Yasuaki Takagi
    International Journal of Biological Macromolecules 148 182 - 191 2020年04月 [査読有り][通常論文]
  • Hồ Quốc Phong, Phan Đình Khôi, Huỳnh Liên Hương, Nguyễn Văn Nhã, Nguyễn Thị Bích Thuyền, Yasuaki Takagi, Lê Thị Minh Thủy, Trần Minh Phú
    Can Tho University Journal of Science 56 199 - 211 2020年 [査読有り][通常論文]
  • Đỗ Thị Thanh Hương, Tăng Minh Kỳ, Nguyễn Thị Kim Hà, Nguyễn Tính Em, Takagi Yasuaki, Nguyễn Thanh Phương
    Can Tho University Journal of Science 56 11 - 19 2020年 [査読有り][通常論文]
  • Major yolk protein binds folic acid in sea urchin
    Ura K, Goto T, Kitano Y, Nishimiya O, Takagi Y
    Aquaculture Science 68 309 - 316 2020年 [査読有り][通常論文]
  • Quantitative changes of major yolk protein in the coelomic fluid and gonads of the sea urchin, Mesocentrotus nudus, during the reproductive cycle.
    Ura K, Suzuki N, Numata H, Tsue S, Satoh M, Takei N, Higuchi I, Yuhi T, Nishimiya O, Takagi Y
    北海道大学水産科学研究彙報 69 29 - 36 2019年 [査読有り][通常論文]
  • Zhang X, Adachi S, Ura K, Takagi Y
    Int. J. Biol. Macromol. 137 809 - 820 2019年 [査読有り][通常論文]
  • Moroi S, MiuraT, Tamura T, Zhang X, Ura K, Takagi Y
    Mater. Sci. Engineer. C 104 109925  2019年 [査読有り][通常論文]
  • Meng D, Tanaka H, Kobayashi T, Hatayama H, Zhang X, Ura K, Yunoki S, Takagi Y
    Int. J. Biol. Macromol. 131 572 - 580 2019年 [査読有り][通常論文]
     
    Non-mammalian collagens have attracted increasing attention for industrial and biomedical use. We have therefore evaluated extraction conditions and the biochemical properties of collagens from aquacultured sturgeon. Pepsin-soluble type I and type II collagen were respectively extracted from the skin and notochord of bester sturgeon by-products, with yields of 63.9 ± 0.19% and 35.5 ± 0.68%. Collagen extraction efficiency was improved by an alkaline pretreatment of the skin and notochord (fewer extraction cycles were required), but the final yields decreased to 56.2 ± 0.84% for type I and 31.8 ± 1.13% for type II. Alkaline pretreatment did not affect the thermal stability or triple-helical structure of both types of collagen. Types I and II collagen formed re-assembled fibril structures in vitro, under different conditions. Alkaline pretreatment slowed down the formation of type I collagen fibrils and specifically inhibited the formation of thick fibril-bundle structures. In contrast, alkaline pretreatment did not change type II collagen fibril formation. In conclusion, alkaline pretreatment of sturgeon skin and notochord is an effective method to accelerate collagen extraction process of types I and II collagen without changing their biochemical properties. However, it decreases the yield of both collagens and specifically changes the fibril-forming ability of type I collagen.
  • Zhang X, Wang J, Tang R, He X, Li L, Takagi Y, Li D
    Front. Physiol. 10 683  2019年 [査読有り][通常論文]
  • Li W, Kobayashi T, Moroi S, Kotake H, Ikoma T, Saeki H, Ura K, Takagi Y
    Carbohydr. Polym. 214 303 - 310 2019年 [査読有り][通常論文]
  • Nishimiya O, Teraoka Y, Gotoh T, Yuhi T, Higuchi I, Ura K, Takagi Y
    Fish. Sci. 85 1 127 - 135 2019年 [査読有り][通常論文]
     
    The major yolk protein in sea urchins is a transferrin-like protein. In this report, a new component was detected in gonad extracts of Strongylocentrotus intermedius and Mesocentrotus nudus, which cross-reacts with antiserum against egg yolk proteins. We tentatively named them egg yolk-related proteins siYRP and mnYRP. The siYRP was purified from testis of S. intermedius by ammonium sulfate fractionation, anion exchange chromatography, affinity chromatography and gel filtration. Purified siYRP was >900kDa in size. The siYRP purified on SDS-PAGE under reducing conditions gave seven bands, corresponding to 93, 213 and >250kDa. Purified mnYRP displayed similar structural characteristics as siYRP. Purified siYRP and mnYRP were identified by tandem mass spectrometry and renamed as siVitellogenin (Vtg)-like and mnVtg-like proteins, respectively. Both Vtg-like proteins were confirmed to be lipoglycoproteins by staining with Sudan black and periodic acid-Schiff. A specific antiserum against the siVtg-like protein was raised in rabbit. Antiserum against the siVtg-like protein immunostained siVtg-like and mnVtg-like proteins. Immunochemical methods using the antiserum revealed that siVtg-like and mnVtg-like proteins were present in the ovary, testis and unfertilized eggs of both species. These results indicated that Vtg-like proteins have important physiological functions for gonadal growth and gametogenesis in sea urchins.
  • Yukiho Sasaoka, Hideki Kishimura, Shinji Adachi, Yasuaki Takagi
    Journal of Food Biochemistry 42 2 e12478  2018年04月01日 [査読有り][通常論文]
     
    We prepared collagen peptides (SCP) from sturgeon by-products: the skin, fin, and bone. The materials were pretreated and hydrolyzed by papain. Finally, we obtained 85.1 g of dried SCP powder from 864 g (wet weight) of the materials. In oral glucose tolerance test (OGTT) with ICR mice, blood glucose levels of SCP group were significantly lower than those of control group. Then, we fractionated SCP by Sephadex column chromatography and all fractions showed hypoglycemic effect. Further, we separated each peptide in the fractions by reversed-phase HPLC. Most of the peptides in these peaks consisted of Gly-X-Y (X and Y are optional amino acid residues) repetitive sequences which are common to the triple helical region of the collagen molecules. Moreover, many peptides contained Pro and Ala residues, which promises to serve as a DPP-IV inhibitor. Altogether, these results suggest the hypoglycemic effect of SCP may be caused by these structural properties. Practical applications: While sturgeon is famous and highly valuable for its salted egg “caviar” and meat, other parts such as skin, fin, and bone, that is, by-products are not fully utilized in seafood industry. In this study, we focused on whole utilization of a sturgeon and prepared collagen peptides (SCP) from sturgeon by-products. The yield of SCP was approximately 100 g SCP/kg wet by-products. In animal experiments, SCP showed hypoglycemic effect. Moreover, the effect is probably caused by Gly-X-Y repetitive sequences derived from the triple helical region of a collagen molecule. The mechanism might be related to DPP-IV inhibitory activity. SCP was white, odorless, and easily soluble in water and it could be advantages in using SCP as an ingredient for functional foods preventing Type 2 diabetes mellitus. The by-products of sturgeon will be a new fishery resource which could be used as a material for collagen peptides providing the hypoglycemic effect.
  • Puteri NE, Astawan M, Pulpi NS, Wresdiyati T, Takagi Y
    Food Sci. Tech. (Campinas) 31 suppl 1 147 - 153 2018年 [査読有り][通常論文]
  • Morphology and anatomy of corallimorpharian Metarhodactis aff. boninensis from Thailand
    Dokkadew S, Kaewsuralikhit C, Takagi Y, Taparhudee W
    Journal of Fisheries and Environment 42 1 - 13 2018年 [査読有り][通常論文]
  • Sato N, Furuta T, Takeda T, Miyabe Y, Ura K, Takagi Y, Yasui H, Kumagai Y, Kishimura H
    Journal of Food Biochemistry 43 2 e12709 - e12709 2018年 [査読有り][通常論文]
  • Yuki Okashita, Heng Wang, Shiori Tsue, Osamu Nishimiya, Kazuhiro Ura, Yasuaki Takagi
    FISHERIES SCIENCE 83 5 803 - 810 2017年09月 [査読有り][通常論文]
     
    In the present study, we examined the localization of the major yolk protein (MYP) in the intestine of the sea urchin Strongylocentrotus intermedius. First, partial MYP complementary DNA was isolated from the sea urchin intestine. The expression level of MYP messenger RNA (mRNA) along the sea urchin digestive tract is highest in the intestine, so we performed in situ hybridization and immunohistochemical analysis using this tissue. No MYP mRNA was detected in the luminal epithelium, connective tissue, muscle tissue, or coelomic epithelium by in situ hybridization analysis. Positive immunohistochemical staining was observed in the luminal epithelium, inner epithelium and connective tissue, the signal being strongest in the latter. We conclude that MYP synthesized in the inner epithelial cells is moved to and stored in connective tissue and the luminal epithelium, before being secreted into the body cavity and the inner digestive cavity of the sea urchin.
  • Md. Tariful Islam Mredha, Nobuto Kitamura, Takayuki Nonoyama, Susumu Wada, Keiko Goto, Xi Zhang, Tasuku Nakajima, Takayuki Kurokawa, Yasuaki Takagi, Kazunori Yasuda, Jian Ping Gong
    BIOMATERIALS 132 85 - 95 2017年07月 [査読有り][通常論文]
     
    Soft supporting tissues in the human body, such as cartilages and ligaments, are tough materials and firmly fixed to bones. These soft tissues, once injured, cannot regenerate spontaneously in vivo. Developing tough and biocompatible hydrogels as artificial soft supporting tissues would substantially improve outcomes after soft tissue injury. Collagen is the main rigid component in soft connective tissues which is organized in various hierarchical arrays. We have successfully developed a novel class of collagen fibril-based tough hydrogels based on the double network (DN) concept using swim bladder collagen (SBC) extracted from Bester sturgeon fish. The DN hydrogels, SBC/PDMAAm, are composed of physically/chemically crosslinked anisotropic SBC fibril as the first network and neutral, biocompatible poly(N,N'-dimethylacrylamide) (PDMAAm) as the second network. The anisotropic structure of SBC fibril network, which is well retained in the DN hydrogels, is formed by free injection method, taking advantage of the excellent fibrillogenesis capacity of SBC. The denaturation temperature of collagen is improved in the DN hydrogels. These DN gels possess anisotropic swelling behavior, exhibit excellent mechanical properties comparable to natural cartilage. The 4 weeks implantation of the gels in the osteochondral defect of rabbit knee also shows excellent biomechanical performance in vivo. Furthermore, the hydroxyapatite (HAp) coated DN gels, HAp/SBC/PDMAAm gels, strongly bond to bone after 4 weeks. This new class of collagen-based hybrid DN gels, as soft and elastic ceramics, having good biomechanical performance and strong bonding ability with bone would expand the choice for designing next generation orthopedic implants such as artificial cartilage, bone defect repair material in the load bearing region of the body. (C) 2017 Elsevier Ltd. All rights reserved.
  • Ura K, Wang H, Hori T, Aizawa S, Tsue S, Satoh M, Takei N, Hoshino K, Higuchi I, Sanuki S, Yuhi T, Nishimiya O, Takagi Y
    Aquaculture Science 65 3 231 - 237 日本水産増殖学会 2017年 [査読有り][通常論文]
  • Noriko Azuma, Seishi Hagihara, Masaki Ichimura, Yasuaki Takagi, Kazuhiro Ura, Shinji Adachi
    ICHTHYOLOGICAL RESEARCH 64 1 139 - 144 2017年01月 [査読有り][通常論文]
     
    Genetic characterization was performed in five individuals of wild Amur sturgeon Acipenser schrenckii, and/or its presumed hybrid caught around Hokkaido, using a mitochondrial DNA (mtDNA) marker and two markers of nuclear DNA (nDNA). Genetic analyses indicated that two of the five fish had the mtDNA haplotype of Kaluga, Huso dauricus, whereas the nDNA markers indicated signs for both A. schrenckii and H. dauricus genotypes, referring to a hybrid origin. The other three fish were plausibly pure A. schrenckii. The results indicated the importance of combined usage of mtDNA and nDNA markers for correct species identification in sturgeon.
  • Takayuki Nonoyama, Susumu Wada, Ryuji Kiyama, Nobuto Kitamura, Md. Tariful Islam Mredha, Xi Zhang, Takayuki Kurokawa, Tasuku Nakajima, Yasuaki Takagi, Kazunori Yasuda, Jian Ping Gong
    ADVANCED MATERIALS 28 31 6740 - + 2016年08月 [査読有り][通常論文]
     
    On implanting hydroxyapatite-mineralized tough hydrogel into osteochondral defects of rabbits, osteogenesis spontaneously penetrates into the gel matrix owing to the semi-permeablility of the hydrogel. The gradient layer (around 40 mu m thick) contributes quite strong bonding of the gel to bone. This is the first success in realizing the robust osteointegration of tough hydrogels, and the method is simple and feasible for practical use.
  • Zhang X, Azuma N, Hagihara S, Ura K, Adahi S, Takagi Y
    Gene 579 1 8 - 16 2016年03月 [査読有り][通常論文]
     
    To characterize type I and II collagen in the Amur sturgeon at the molecular level, mRNAs encoding the pro alpha chain of both types of collagen were cloned and sequenced. Full sequences of both were obtained, and the molecular phylogeny based on the deduced amino acid sequence indicated that the correct sequences of the target genes were obtained. Analyses of primary structure of the pro alpha chains revealed that type I and II collagen share the basic structure of the prom chain of fibril collagen, but have different characteristics, especially in residues related to thermal stability. In the triple helical domain, Gly-Pro-Pro sequence stabilizing the tripeptide unit was more frequent in type II than in type I, and Gly-Gly, which likely decline in thermal stability, was more frequent in type I than in type II. These results suggested that the denaturation temperature of type II would be remarkably higher than type I. The spatial pattern of gene expression was analyzed by quantitative real-time PCR, which showed that relatively ubiquitous type I gene and strongly skewed distribution of type II gene, which highly expressed only in vertebra, snout cartilage, and notochord. This pattern was similar to the distribution pattern of each collagen protein detected by previous biochemical analyses using Amur and Bester sturgeons. The present study is the first report of the cloning of the full-length cDNAs for both of type I and type II collagen in the Amur sturgeon, and is the first comparative analysis of type I and II collagens in a sturgeon species at the molecular level. The results provide basic and general information on collagens in sturgeons. (C) 2015 Elsevier B.V. All rights reserved.
  • Frolan A. Aya, Vicar Stella N. Nillasca, Luis Maria B. Garcia, Yasuaki Takagi
    ICHTHYOLOGICAL RESEARCH 63 1 121 - 131 2016年01月 [査読有り][通常論文]
     
    The embryonic and larval development of hatchery-reared silver therapon Leiopotherapon plumbeus are described to provide essential information on the early life history of this species. Egg size, larval size at hatching, yolk resorption rate, onset of feeding and development of some morphological characters were examined. Fertilized eggs (430-610 A mu m in diameter) were spherical, yellowish, demersal and slightly adhesive. First cleavage occurred 6 min post-fertilization and embryos hatched 21-24 h post-fertilization under ambient temperature of 27.5 +/- A 0.1 A degrees C. Newly hatched larvae [1.79 +/- A 0.04 mm in total length (TL)] with yolk volume of 0.579 +/- A 0.126 mm(3) had no functional or pigmented eyes, mouth or digestive tract. The eyes became fully pigmented and mouth opened [31 and 36.5 hours post-hatching (hph)] shortly before yolk resorption at 39 hph and when larvae had grown to 2.65 +/- A 0.14 mm in TL. Some morphological characters such as total length, pre-anal length and eye diameter decreased following yolk resorption, which also coincided with the development of foraging capacities shortly before exogenous feeding was initiated. L. plumbeus larvae initiated exogenous feeding at 54 hph, indicating a short (15 h after yolk resorption) transitional feeding period. Larval growth at the early stages of development (54-72 hph) was rapid and steadily increased from 288 to 720 hph, when larvae, 12.05 +/- A 4.02 mm in TL, closely resembled the external characteristics of their adult conspecifics.
  • Heng Wang, Kazuhiro Ura, Yasuaki Takagi
    FISHERIES SCIENCE 81 6 1127 - 1134 2015年11月 [査読有り][通常論文]
     
    Major yolk protein (MYP) is the most abundant protein found in the yolk granules of sea urchin eggs. The structure of MYPs stored in the eggs of two sea urchin species from Strongylocentrotus intermedius and Mesocentrotus nudus were investigated. Egg-localized major yolk protein (EGMYP) extracted from the eggs of two species of sea urchins was assessed using disc-polyacrylamide gel electrophoresis and immunoelectrophoresis. The molecular weight of native EGMYP was 595 in S. intermedius eggs and 625 kDa in M. nudus eggs. The use of sodium dodecyl sulfate-polyacrylamide gel electrophoresis and Western blotting analysis under reducing conditions revealed that the EGMYP of S. intermedius separated into four bands (approximately 172, 116, 74 and 68 kDa), while the EGMYP of M. nudus resolved as a set of bands ranging from 175 to 58 kDa (approximately 175, 165, 153, 115, 102, 90, 78, 65 and 58 kDa). Yolk granules from eggs were isolated using sucrose density ultracentrifugation and examined using electron microscopy. The structures of purified EGMYP extracted from eggs and from yolk granules were similar in both species. The EGMYP stored in the eggs of the sea urchins was a glycoprotein complex, the protein structure of which, however, varied between the two species.
  • Md. Tariful Islam Mredha, Xi Zhang, Takayuki Nonoyama, Tasuku Nakajima, Takayuki Kurokawa, Yasuaki Takagi, Jian Ping Gong
    JOURNAL OF MATERIALS CHEMISTRY B 3 39 7658 - 7666 2015年 [査読有り][通常論文]
     
    Marine collagen has been attracting attention as a medical material in recent times due to the low risk of pathogen infection compared to animal collagen. Type I collagen extracted from the swim bladder of Bester sturgeon fish has excellent characteristics such as high denaturation temperature, high solubility, low viscosity and an extremely fast rate to form large bundle of fibers under certain conditions. These specific characteristics of swim bladder collagen (SBC) permit us to create stable, disk shaped hydrogels with concentric orientation of collagen fibers by the controlled diffusion of neutral buffer through collagen solution at room temperature. However, traditionally used animal collagens, e.g. calf skin collagen (CSC) and porcine skin collagen (PSC), could not form any stable and oriented structure by this method. The mechanism of the superstructure formation of SBC by a diffusion induced gelation process has been explored. The fast fibrillogenesis rate of SBC causes a quick squeezing out of the solvent from the gel phase to the sol phase during gelation, which builds an internal stress at the gel-sol interface. The tensile stress induces the collagen molecules of the gel phase to align along the gel-sol interface direction to give this concentric ring-shaped orientation pattern. On the other hand, the slow fibrillogenesis rate of animal collagens due to the high viscosity of the solution does not favor the ordered structure formation. The denaturation temperature of SBC increases significantly from 31 degrees C to 43 degrees C after gelation, whereas that of CSC and PSC were found to increase a little. Rheology experiment shows that the SBC gel has storage modulus larger than 15 kPa. The SBC hydrogels with thermal and mechanical stability have potential as bio-materials for tissue engineering applications.
  • ホタテ貝殻から創製した物理ー化学的識別物質
    下野功, 高橋志郎, 森千太郎, 佐藤克行, 小林淳哉, 都木靖彰
    北海道立工業技術センター研究報告 13 18 - 25 2014年12月 [査読無し][通常論文]
  • Norihiko Komatsu, Nobuhiro Ogawa, Kurin Iimura, Kazuhiro Ura, Yasuaki Takagi
    FISHERIES SCIENCE 80 6 1249 - 1256 2014年11月 [査読有り][通常論文]
     
    Fish scales are a potential source of collagen for fabricating scaffolds for cells during tissue engineering because fish collagen has a low risk of zoonosis. Since the assembly of collagen fibrils has a significant impact on the functionality of the scaffold, the ability to replicate the fibril assembly of human tissues is critical. To determine the mechanism of fish collagen fibril assembly, we first identified non-collagenous proteins (NCPs), the potential regulators of fibril assembly in vivo, and then used tandem mass spectrometry to analyze the NCPs contained in the basal plates of goldfish Carassius auratus scales, a collagenous plate which is characterized by a plywood-like assembly of collagen fibrils similar to that found in the cornea. We identified a 19-kDa acidic protein as dermatopontin, the NCP which is a possible regulator of fibril assembly in the mammalian cornea. We cloned a goldfish dermatopontin cDNA of 1,074 bp containing an open reading frame encoding 196 amino acids. Reverse transcription-PCR revealed that dermatopontin mRNA was expressed in a wide range of tissues, including scale, skin, fin, eye, and skeletal muscle. In situ hybridization revealed that dermatopontin mRNA was expressed primarily in the basal plate-producing hyposquamal scleroblasts of the scales, suggesting that the dermatopontin is linked to the collagen fibril assembly of the basal plate.
  • Xi Zhang, Mika Ookawa, Yongkai Tan, Kazuhiro Ura, Shinji Adachi, Yasuaki Takagi
    FOOD CHEMISTRY 160 305 - 312 2014年10月 [査読有り][通常論文]
     
    Collagens purified from Bester sturgeon organs were characterised biochemically, and their fibril-forming abilities and fibril morphologies formed in vitro clarified. Yields of collagens were 2.1%, 11.9%, 0.4%, 18.1%, 0.4%, 0.8% and 0.03% (collagen dry weight/tissue wet weight) from scales, skin, muscle, swim bladder, digestive tract, notochord and snout cartilage, respectively. Using SDS-PAGE and amino acid composition analyses, collagens from scales, skin, muscle, the swim bladder and digestive tract were characterised as type I, and collagens from the notochord and snout cartilage as type II. Denaturation temperatures of the collagens, measured using circular dichroism, were 29.6, 26.8, 29.0, 32.9, 31.6 and 36.3 degrees C in scales, skin, muscle, swim bladder, digestive tract, and notochord, respectively. For fibril formation, swim bladder and skin collagen showed a more rapid rate of increase in turbidity, a shorter time to attain the maximum turbidity, and formed thicker fibrils compared with porcine tendon type I collagen. (C) 2014 Elsevier Ltd. All rights reserved.
  • Kenta Susuki, Masaki Ichimura, Yosuke Koshino, Masahide Kaeriyama, Yasuaki Takagi, Shinji Adachi, Hideaki Kudo
    JOURNAL OF MORPHOLOGY 275 5 514 - 527 2014年05月 [査読有り][通常論文]
     
    Mature male Pacific salmon (Genus Oncorhynchus) develop a dorsal hump, as a secondary male sexual characteristic, during the spawning period. Previous gross anatomical studies have indicated that the dorsal humps of salmon are mainly composed of cartilaginous tissue (Davidson [1935] J Morphol 57:169-183.) However, the histological and biochemical characteristics of such humps are poorly understood. In this study, the detailed microstructures and components of the dorsal humps of pink salmon were analyzed using histochemical techniques and electrophoresis. In mature males, free interneural spines and neural spines were located in a line near to the median septum of the dorsal hump. No cartilaginous tissue was detected within the dorsal hump. Fibrous and mucous connective tissues were mainly found in three regions of the dorsal hump: i) the median septum, ii) the distal region, and iii) the crescent-shaped region. Both the median septum and distal region consisted of connective tissue with a high water content, which contained elastic fibers and hyaluronic acid. It was also demonstrated that the lipid content of the dorsal hump connective tissue was markedly decreased in the mature males compared with the immature and maturing males. Although, the crescent-shaped region of the hump consisted of connective tissue, it did not contain elastic fibers, hyaluronic acid, or lipids. In an ultrastructural examination, it was found that all of the connective tissues in the dorsal hump were composed of collagen fibers. Gel electrophoresis of collagen extracts from these tissues found that the collagen in the dorsal hump is composed of Type I collagen, as is the case in salmon skin. These results indicate that in male pink salmon the dorsal hump is formed as a result of an increase in the amount of connective tissue, rather than cartilage, and the growth of free interneural spines and neural spines. J. Morphol. 275:514-527, 2014. (c) 2013 Wiley Periodicals, Inc.
  • Yongkai Tan, Kurin Iimura, Tetsuro Sato, Kazuhiro Ura, Yasuaki Takagi
    Gene 516 2 277 - 284 2013年03月10日 [査読有り][通常論文]
     
    There has been significant interest in the expression and function of dermatopontin (DPT) in mammals owing to recent evidence pointing to its critical role in collagen fibrillogenesis. Despite this interest, limited information is available about the site/s of DPT mRNA expression or changes in expression in vivo. We used reverse-transcription polymerase chain reaction and in situ hybridization to evaluate the spatial and temporal pattern of DPT mRNA expression in zebrafish, Danio rerio, a widely used vertebrate model. We observed that DPT transcripts were expressed in zebrafish embryos at all developmental stages in a range of tissues, including the brain and optic neuron cells. Based on our results, we hypothesize that DPT may also play a role in neural functions in vivo. © 2012 Elsevier B.V.
  • X. Zhang, K. Shimoda, K. Ura, S. Adachi, Y. Takagi
    JOURNAL OF FISH BIOLOGY 81 6 1985 - 2004 2012年11月 [査読有り][通常論文]
     
    In the larval bester, a hybrid sturgeon of beluga Huso huso and sterlet Acipenser ruthenus, development of cartilage around the notochord began 7 days post hatch (dph) (14.0 mm, total length, L-T). The vertebral cartilage develops in the following sequence: basidorsals and basiventrals, neural canals, neural spines and ribs. The development of ribs remained incomplete in the largest specimen (181 dph, 179 mm L-T) that was examined. Endoskeletal development of the fins began 4 dph for the dorsal and anal fins, 6 dph for the pectoral fin and 10 dph for the caudal and pelvic fins. Complete elements of all fins were observed by 91 dph and complete ossification of fin rays was observed by 122 dph in the double-stained specimens. Observation of the histological sections, however, suggested that ossification occurred soon after the formation of the organic matrix in the fin rays. Dorsal scutes were first visible by 25 dph, followed by the lateral and ventral scutes, which were visible by 37 and 44 dph, respectively. The number of scutes was fixed at 44, 59 and 91 dph and ossification was complete by 59 (dorsal) and 91 dph (lateral and ventral scutes) in the double-stained specimens. Ossification occurred soon after the formation of the scute organic matrix in the histological sections. Four types of scales were observed in the H. huso x A. ruthenus hybrid. Median predorsal, preanal and small scales on the anterior section of the head were visible by 59 dph. Scales on the caudal fin were visible by 91 dph and a variable assemblage of scales anterior to the anal fin was visible by 122 dph. Both the scutes and scales developed in a process that is similar to that of intramembranous ossification. (C) 2012 The Authors Journal of Fish Biology (C) 2012 The Fisheries Society of the British Isles
  • Syuto Hasegawa, Kazuhiro Ura, Hiroyuki Tanaka, Takao Ojima, Yasuaki Takagi
    FISHERIES SCIENCE 78 5 1107 - 1115 2012年09月 [査読有り][通常論文]
     
    We isolated a cellulase from the digestive organs of the short-spined sea urchin Strogylocentrotus intermedius using a combination of ion-exchange chromatography and gel filtration together with an assay for carboxymethylcellulase activity. The isolated cellulase was stained as a single band by Congo red. The molecular weight of the isolated cellulase, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing conditions, was 59 kDa. The isolated cellulase exhibited hydrolytic activity toward carboxymethyl cellulose, with an optimum temperature and pH of 30 A degrees C and pH 8.0, respectively. The thermal stability of the enzyme was characterized by determining the temperature at which activity decreased by 50 % with treatment for 30 min at pH 7.0 and found to be 32 A degrees C. Cellulase activity remained at a high level at 5-20 A degrees C, which is the growth temperature of the short-spined sea urchin. These results confirm that the short-spined sea urchin should preferably be reared at a water temperature of < 20 A degrees C.
  • George Shigueki Yasui, Takafumi Fujimoto, Lenin Arias-Rodriguez, Yasuaki Takagi, Katsutoshi Arai
    AQUACULTURE 344 147 - 152 2012年05月 [査読有り][通常論文]
     
    The solutions commonly used to dilute or cryopreserve sperm are commonly composed of salts, buffers and cryoprotectants, which may affect gametes and subsequent fertilization success. Here, we have evaluated the effects of several cryoprotectants (methanol; MeOH, dimethyl sulfoxide; DMSO and dimethyl acetamide; DMA at concentrations of 0.25, 0.5 and 1%) and different ions (potassium, calcium and magnesium at concentrations of 1.25, 2.5, 5.0 and 10 mM) as sperm diluents upon sperm motility and fertilization success in the loach Misgurnus anguillicaudatus sperm. Our results demonstrated that DMSO (at 1%) decreased sperm motility while calcium and magnesium ions (from 2.5 mM) induced sperm aggregation and reduced sperm motility. Reduced fertilization rates were observed with potassium (from 1.25 mM), calcium (at 10 mM), magnesium (at 10 mM), DMA (at 1%), and DMSO (at 1%). We conclude that specific ions and cryoprotectants, and their relative concentrations caused effect upon loach gametes. These data are important to consider for the preparation of sperm diluents and activating solutions in order to manage gamete quality for artificial propagation. (C) 2012 Elsevier B.V. All rights reserved.
  • Kurin Iimura, Hidekazu Tohse, Kazuhiro Ura, Yasuaki Takagi
    JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 318B 3 190 - 198 2012年05月 [査読有り][通常論文]
     
    Teleost fish scale is a dermal skeleton equipped with a strong regenerative ability. Owing to this regenerative ability, teleost fish scale can be used as a model for the regeneration of the dermal skeleton. However, there is insufficient fundamental knowledge of the regeneration, and this limits the usage of fish scale. In this study, as a first step toward understanding the molecular mechanism of the cellular differentiation during scale regeneration, we cloned the cDNAs for osteoblast-related proteins (Runx2, Sparc, and Bgp) in goldfish, and analyzed their expressions during scale regeneration. The expression profiles of these genes during scale regeneration were similar to those during mammalian osteoblastic differentiation. Specifically, runx2 expression was increased at the earliest time point, followed by sparc expression and then bgp expression. In the earlier stages, these genes were expressed in cells that formed cellular condensations and the flat cells surrounding them in the scale pocket. As the regeneration proceeded, the expressions became restricted to the episquamal, hyposquamal, and marginal scleroblasts and the cells around the marginal area of the regenerating scale. These results strongly suggest that (1) the differentiation mechanism of scleroblasts is similar to that of mammalian osteoblasts and odontoblasts, (2) scleroblast differentiation occurs around the cellular condensations at the early regeneration stage and is restricted to the marginal area of the scale at the later stage, and (3) the differentiation mechanisms are similar between the episquamal scleroblasts that produce the external layer and the hyposquamal scleroblasts that produce the basal plate. J. Exp. Zool. (Mol. Dev. Evol.) 318:190198, 2012. (c) 2012 Wiley Periodicals, Inc.
  • Kazuhiro Ura, Syuto Hasegawa, Eri Tanaka, Takahiro Gotoh, Takao Ojima, Yasuaki Takagi
    ANATOMICAL RECORD-ADVANCES IN INTEGRATIVE ANATOMY AND EVOLUTIONARY BIOLOGY 295 1 73 - 77 2012年01月 [査読有り][通常論文]
     
    Subtilase, a major protease in the short-spined sea urchin (Strongylocentrotus intermedius), was isolated and used as antigen for the subsequent production of a specific polyclonal antibody. Immunoreactive cells were observed by immunohistochemical analysis in granules in the anterior and posterior stomach and the anterior intestine. These granules, which were most numerous in the anterior stomach, also stained intensely with methylene blue-Azure II. However, granules in cells of the esophagus, posterior intestine, and rectum were not stained by this antibody. We conclude that subtilase mainly localizes in the stomach and anterior intestine of the sea urchin. Anat Rec, 2012. (C) 2011 Wiley Periodicals, Inc.
  • 下野功, 高橋志郎, 森千太郎, 佐藤克行, 小林淳哉, 都木靖彰
    北海道立工業技術センター研究報告 12 31 - 37 テクノポリス函館技術振興協会 2012年 [査読無し][通常論文]
     
    ホタテガイ貝殻の利活用は、大量使用の見込める製品(土壌改良材等)の低コスト化と、少量でも付加価値の高い製品の創製というように、目的別に取組むことが望ましい。本研究では、ホタテガイ貝殻から高機能材料を創製することを目的とし、ホタテガイ貝殻が持つ蛍光機能を活かした応用研究を行った。本研究の結果、貝殻製蛍光体の4つの発光帯の強度比は、食品の灰化処理を目的として行なった熱処理に対し、高い安定性を示した。この結果に基づき、ホタテガイ貝殻から創製した貝殻製蛍光体の、発光帯の強度比を識別番号と見なし、これを食品やサプリメントのロット番号や製造年月日等の情報と対応させることで、包装容器と中身との同一性を証明するための目印となる食品用標識剤を提案した。
  • Nobuhiro Ogawa, Kazuhiro Ura, Yasuaki Takagi
    FISHERIES SCIENCE 76 2 189 - 198 2010年03月 [査読有り][通常論文]
     
    The external layer of a teleost fish scale is composed of type I collagen, an amorphous matrix substance and hydroxyapatite crystals. Calcification of this layer can be inhibited in the scale-regenerating process under calcium-and phosphate-deficient (CaDPD) conditions, and can be facilitated by incubation in physiological saline. The aim of this study was to evaluate this model of calcification using histological and quantitative analysis in order to promote further understanding of the mechanism of calcification in fish scales. We found that the external layer of the scales produced under CaDPD conditions contained more densely aligned collagen fibrils with a small amount of the amorphous matrix substance. The CaDPD scale contained only one-third of the amount of calcium and phosphate present in the control fish. After 4 hours of incubation, a two-to threefold increase in calcium content and a 1.5-fold increase in phosphate content were observed. Calcification proceeded in the external layer, and mineral deposits grew only in the electron-dense matrix substance. We conclude that this model would be suitable for studying the early process of fish scale calcification that occurs in the noncollagenous substance. The electron-dense substance may contain key molecules that promote calcification.
  • Hidekazu Tohse, Kazuko Saruwatari, Toshihiro Kogure, Hiromichi Nagasawa, Yasuaki Takagi
    CRYSTAL GROWTH & DESIGN 9 11 4897 - 4901 2009年11月 [査読有り][通常論文]
     
    We show that the high-molecular weight (HMW) protein aggregate of fish otolith matrix is involved in the regulation of crystal polymorphs during otolith biomineralization. Teleost fish otoliths are biominerals that contain calcium carbonate aragonite or vaterite crystals. In a previous study, we identified a novel protein named otolith matrix macromolecule-64 (OMM-64) within the otolith organic matrix. In addition, we revealed that the HMW aggregate of otolith matrix architecture was comprised of OMM-64, in which inner-ear-specific short-chain collagen otolin-1 was also contained. By using an in vitro crystallization system in the absence of magnesium ions here, we show that native OMM-64 induced vaterite crystals, whereas native otolion-1 induced calcite crystals. However, the aggregate complex induced the aragonite polymorph ill the same condition. The present data suggest that separation and Structural and functional analyses of each matrix protein ill the aggregate are absolutely imperative, but functional examination of the protein complex itself is equally important in clarifying polymorph control of biomineralization.
  • 小林 豊, 高村 巧, 下野 功, 浦 和寛, 都木 靖彰
    水産増殖 = The aquiculture 57 2 271 - 278 水産増殖談話会 2009年06月 [査読有り][通常論文]
     
    岩手県大槌産、岩手県山田産、北海道鹿部産、北海道知内産の2年貝養殖ホタテガイの貝殻中のLi、Mn、SrおよびBa濃度を誘導結合プラズマ質量分析装置を用いて測定したところ、産地により微量元素組成に有意な差が認められた。MANOVAの判別分析を用いて産地識別を試みたところ、48個体中9個体で誤判別が発生し、判別的中率は81.3％であった。大槌産と他の産地との間で誤判別される例が多かったが、そのほかの産地間の誤判別は少なかった。同様の方法を用いて岩手県八幡平産および北海道七飯産の養殖ニジマスの耳石中の微量元素濃度を定量した結果、その組成にも産地により有意な差があった。判別的中率は95.5％であった。生産年による微量元素組成の変動が小さければ、貝殻および耳石微量元素組成による産地識別が可能であると考えられる。
  • Konomi Sakamoto, Wataru Honto, Masaharu Iguchi, Nobuhiro Ogawa, Kazuhiro Ura, Yasuaki Takagi
    Fisheries Science 75 1 91 - 98 2009年02月 [査読有り][通常論文]
     
    This study examines the following in the Japanese mitten crab: (1) the structure of the exoskeleton with special reference to its calcification (2) the progression of post-molt cuticle formation and calcification. In the crab, the structure and calcification state of the exoskeleton at the molt and during the inter-molt stage were similar to those of other crustaceans. During the inter-molt, the exoskeleton consisted of four cuticle layers the outermost epicuticle, the exocuticle, the endocuticle and the innermost membrane layer. Intense calcification was observed in the exo- and endocuticle. At the molt, the synthesis of the epi- and exocuticle was already complete, and the addition of the endocuticle began after the molt. Calcification of the exocuticle initiated soon after the molt, but there was a delay between endocuticle matrix synthesis and calcification. Histology showed that the process of calcification was similar to that in other crustaceans. However, calcium concentrations within the exoskeleton continued to increase and never reached the levels of the inter-molt stage at the end of the experiment. This suggests that the Japanese mitten crab is relatively slow to calcify compared to other crustaceans. © 2008 The Japanese Society of Fisheries Science.
  • 浦 和寛, 田中 恵梨, 東藤 孝, 後藤 孝弘, 清水 幹博, 尾島 孝男, 都木 靖彰
    北海道大学水産科学研究彙報 58 3 21 - 28 北海道大学大学院水産科学研究院 = Research Faculty of Fisheries Sciences, Hokkaido University 2009年02月 [査読無し][通常論文]
     
    We purified a subtilase from digestive system of short spined sea urchin Strongylocentortus intermedius by a combination of ion-exchange chromatography and gel filtration. The molecular weight of purified subtilase on SDS-PAGE under both reducing and nonreducing conditions was 35,000. Antiserum against subtilase specifically immunostained its antigen. By Western blot analysis, immunoreactive with this antibody were observed in stomach and intestine.
  • Hidekazu Tohse, Yasuaki Takagi, Hiromichi Nagasawa
    FEBS JOURNAL 275 10 2512 - 2523 2008年05月 [査読有り][通常論文]
     
    In the biomineralization processes, proteins are thought to control the polymorphism and morphology of the crystals by forming complexes of structural and mineral-associated proteins. To identify such proteins, we have searched for proteins that may form high-molecular-weight (HMW) aggregates in the matrix of fish otoliths that have aragonite and vaterite as their crystal polymorphs. By screening a cDNA library of the trout inner ear using an antiserum raised against whole otolith matrix, a novel protein, named otolith matrix macromolecule-64 (OMM-64), was identified. The protein was found to have a molecular mass of 64 kDa, and to contain two tandem repeats and a Glu-rich region. The structure of the protein and that of its DNA are similar to those of starmaker, a protein involved in the polymorphism control in the zebrafish otoliths [Sollner C, Burghammer M, Busch-Nentwich E, Berger J, Schwarz H, Riekel C & Nicolson T (2003) Science302, 282-286]. Ca-45 overlay analysis revealed that the Glu-rich region has calcium-binding activity. Combined analysis by western blotting and deglycosylation suggested that OMM-64 is present in an HMW aggregate with heparan sulfate chains. Histological observations revealed that OMM-64 is expressed specifically in otolith matrix-producing cells and deposited onto the otolith. Moreover, the HMW aggregate binds to the inner ear-specific short-chain collagen otolin-1, and the resulting complex forms ring-like structures in the otolith matrix. Overall, OMM-64, by forming a calcium-binding aggregate that binds to otolin-1 and forming matrix protein architectures, may be involved in the control of crystal morphology during otolith biomineralization.
  • Masayuki Iigo, Tomotaka Abe, Saori Kambayashi, Kaoru Oikawa, Tomohiro Masuda, Kanta Mizusawa, Shoji Kitamura, Teruo Azuma, Yasuaki Takagi, Katsumi Aida, Tadashi Yanagisawa
    GENERAL AND COMPARATIVE ENDOCRINOLOGY 154 1-3 91 - 97 2007年10月 [査読有り][通常論文]
     
    In many teleost species, the photoreceptive pineal organ harbors the circadian clock that regulates melatonin release in the pineal organ itself. However, the pineal organ of three salmonids (rainbow trout Oncorhynchus mykiss, masu salmon Oncorhynchus masou, and sockeye salmon Oncorhynchus nerka) did not exhibit cireadian rhythms in melatonin release when maintained under constant darkness (1313) in vitro, suggesting that the pineal organs of all salmonids lack the circadian regulation of melatonin production. To test this hypothesis, the pineal organ of seven salmonids (common whitefish Coregonus lavaretus, grayling Thymallus thymallus, Japanese huchen Hucho perryi, Japanese charr Salvelius leucomaenis pluvius, brook trout Salvelius fontinalis, brown trout Salmo trutta and chum salmon Oncorhynchus keta) and closely related osmerids (ayu Plecoglossus altivelis altivelis and Japanese smelt Hypomesus nipponensis) were individually maintained in flow-through culture at 15 degrees C under several light conditions. Under light-dark cycles, the pineal organ of all species showed a rhythmic melatonin release with high rates during the dark phase. Under DD, the osmerid pineal organs exhibited circadian rhythms in melatonin release with high rates only during the subjective-night but the salmonid pineal organs constantly released melatonin at high rates. Under constant light, melatonin release was suppressed in all species. The pineal organ of rainbow trout maintained at different temperature (15, 20 or 25 degrees C under DD released melatonin with high rates but the amount of melatonin released was temperature-sensitive (highest at 20 degrees C). Thus, melatonin release from the pineal organ of osmerids is regulated by both light and circadian clock but the circadian regulation is lacking in salmonids. These results indicate that ancestral salmonids lost the circadian regulation of melatonin production after the divergence from osmerid teleosts. (C) 2007 Elsevier Inc. All rights reserved.
  • Yasuaki Takagi, Kazuhiro Ura
    Journal of Nanoscience and Nanotechnology 7 3 757 - 762 2007年03月01日 [査読有り][通常論文]
     
    The corneal stroma is composed of multiple lamellae, each containing closely packed collagen fibrils. The orientation of fibrils in a lamella is parallel, but those in different lamellae are orthogonal. As a result, the corneal stroma has a characteristic orthogonal plywood-like structure. Such a highly-regulated three-dimensional arrangement of collagen fibrils gives strength and transparency to the corneal stroma, but it also presents a challenge in the fabrication of materials to replace it. A bioinspired technology is required to process such materials, but the regulatory mechanism of collagen-fibril orientation is still unknown. The low regenerating activity of the corneal stroma seems to be a major factor preventing progress in this field of research. A similarly highly-ordered arrangement of collagen fibrils can be seen in the basal plates of teleost fish scales. Moreover, the scales have high regenerating ability. When a scale is mechanically lost, a new scale is rapidly regenerated. The cells that produce the basal plates are extremely activated; thus, production of the highly-ordered collagen fibrils is very rapid. Therefore, the regenerating scales should be a uniquely helpful biological model for studying the regulatory mechanism of collagen-fibril orientation. Fish-scale collagen has another advantage for use as a biomaterial: the low probability of zoonotic infection. Therefore, scale collagen is a most promising biomaterial for fabricating three-dimensionally arranged collagen fibers to substitute for the corneal stroma. Three tasks that must be clarified for the bioinspired production of a corneal substitute from fish scale collagen are proposed.
  • Takaomi Arai, Takafumi Hirata, Yasuaki Takagi
    MARINE ENVIRONMENTAL RESEARCH 63 1 55 - 66 2007年02月 [査読有り][通常論文]
     
    Trace element levels in otoliths of chum salmon Oncorhynchus keta were examined by means of laser ablation inductively coupled plasma mass spectrometry (LA-ICPMS). A close linear relationship in the Sr:Ca ratios between EPMA (X-ray analysis with an electron microprobe) and LA-ICPMS analyses was found (p < 0.0001), suggesting that the latter technique could be used to separate the marine and freshwater life phases. Mg:Ca, Cr:Ca, Zn:Ca and Ba:Ca ratios in either the core region or the oceanic growth zone of the otoliths varied among sites. These differences suggest that elemental compositions may reflect environmental variability among spawning (breeding) or habitat sites. Thus, those element ratios demonstrate the potential to be used to distinguish between fish spawning (breeding) sites and habitats for this species of salmon. (c) 2006 Elsevier Ltd. All rights reserved.
  • Yasuharu Ohira, Motohiro Shimizu, Kazuhiro Ura, Yasuaki Takagi
    FISHERIES SCIENCE 73 1 46 - 54 2007年02月 [査読有り][通常論文]
     
    The time-course changes in calcium and phosphorus contents, dry weight, and area during scale regeneration in the goldfish Carassius auratus L. were quantified. Histological observations were then conducted to understand the mutual relationship between the quantitative and morphological processes of scale regeneration. The quantitative study revealed that regenerating scales grow most rapidly in area during the first 5 days of regeneration. The gradual decrease in the area growth rate coupled with the continuous linear weight growth over the period of 5-28 days suggests a shift in growth priority from area growth to the apposition of the basal plate. Calcium and phosphorus deposition proceeded almost linearly during scale regeneration. Calcification of the bony layer preceded that of the basal plate and, after 14 days of regeneration, calcification of the basal plate started and gradually progressed. On day 28, recovery of calcium and phosphorus contents in the regenerating scales were approximatley 72% of ontogenetic scales, which is lower than the rates of area and weight regeneration (104 and 85%, respectively). Late initiation and slow progress of calcification in the basal plate is suggested to be responsible for the slow regeneration in calcium and phosphorus contents.
  • Hidekazu Tohse, Emi Murayama, Tsuyoshi Ohira, Yasuaki Takagi, Hiromichi Nagasawa
    COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY B-BIOCHEMISTRY & MOLECULAR BIOLOGY 145 3-4 257 - 264 2006年11月 [査読有り][通常論文]
     
    Physiological studies have suggested that carbonic anhydrase (CA) plays a central role in otolith biomineralization via ion transport. However, the presence and exact function of CA in the inner ear have not been determined. In the present study, to investigate the localization of CA and its involvement in otolith calcification, we cloned two cDNAs encoding CAs from the rainbow trout sacculus. These two cDNAs, designated rainbow trout CAa (rtCAa) and rtCAb, both had an open reading frame encoding 260 amino acids with a sequence identity of 78%. Remarkably, rtCAb has a high degree of homology (82%) with "high activity CA" in the zebrafish, and its mRNA expression showed variation in the range 1.9-11.4 x 10(4) copies/ng total RNA in the sacculus. In contrast, rtCAa mRNA was constantly expressed at approximately 3 x 10(4) copies/ng total RNA. In situ hybridization revealed that rtCAb mRNA was strongly expressed in the distal squamous epithelial cells and transitional epithelial cells, except the mitochondria-rich cells, whereas, rtCAa was localized in extrasaccular tissue. These results suggest that the rtCAb isozyme is involved in the daily increment formation and calcification of otoliths via phase and spatial differences of the bicarbonate supply to the endolymph. (c) 2006 Elsevier Inc. All rights reserved.
  • Yoshifumi Sawada, Manabu Hattori, Naoko Sudo, Keitaro Kato, Yasuaki Takagi, Kazuhiro Ura, Michio Kurata, Tokihiko Okada, Hidemi Kumai
    Aquaculture Research 37 8 805 - 812 2006年06月 [査読有り][通常論文]
     
    A previous study elucidated that an extreme hypoxia during somitogenesis induced the most frequent skeletal malformation centrum defects in red sea bream (RSB), Pagrus major. In this study, details of the hypoxic conditions to induce them in RSB, dissolved oxygen (DO) concentration and exposure time to hypoxia, were investigated. Fertilized eggs were exposed to seawater of six DO concentrations (0%, 10%, 25%, 50%, 75% and 100% of saturation) for seven different periods (5, 10, 30, 60, 120, 240 and 360 min) during somitogenesis. Somitic disturbances in newly hatched larvae were induced by exposure to 0% and 10% DO concentration for 10 and 120 min and longer respectively. Rearing eggs exposed to hypoxic condition of 10% DO for 240 min for 40 days post-hatch showed that the location and the frequency of somitic disturbances in larvae and centrum defects in juveniles were significantly correlated (P< 0.01). Dissolved oxygen concentration of the interstitial water in the egg high density layer formed at the water surface in a stationary state abruptly decreased to 3.7% within 7 min. Centrum defect induction by exposure of eggs to extreme low DO concentrations for a short period, which is the probable situation in the practical juvenile production, suggests that careful maintenance of DO concentration is important in the incubating water of fertilized eggs during egg sorting and transportation, where eggs are made into a pile and undergo hypoxia, for the prevention of centrum defects. © 2006 Blackwell Publishing Ltd.
  • Induction of centrum defects in amberjack, Seriola dumerili, by exposure of embryos to hypoxia.
    Sawada Y, Hattori M, Iteya M, Takagi Y, Ura K, Seoka M, Kato K, Kurata M, Miyatake H, Katayama A, Kumai H
    Fisheries Science 72 364 - 372 2006年03月 [査読有り][通常論文]
  • 下野 功, 高村 巧, 保坂 知世子, 小林 淳哉, 都木 靖彰, 山元 明
    日本セラミックス協会学術論文誌 : Nippon Seramikkusu Kyokai gakujutsu ronbunshi 114 1328 341 - 346 社団法人日本セラミックス協会 2006年 [査読無し][通常論文]
     
    We studied new preparation conditions for scallop shell phosphors to suppress weathering and the disappearance of fluorescence, and measured the fluorescence properties of these phosphors. When a shell was fired to 900°C in a carbon dioxide atmosphere, weathering and the disappearance of fluorescence could be suppressed. It was found that the higher brightness of the shell phosphor fired at 860°C was about 6cd/m2, when the power of irradiated UV light was about 1.6 W/m2. The emission spectrum shows three bands, with peaks at about 420 nm, 485 nm and 585 nm. The bands at 420 nm and 485 nm are presumed to be due to Cu, and the band at 585 nm is presumed to be due to Mn.
  • Hiroaki Yoshikubo, Nobuo Suzuki, Keiju Takemura, Masahiro Hoso, Sayaka Yashima, Shawichi Iwamuro, Yasuaki Takagi, Makoto J. Tabata, Atsuhiko Hattori
    Life Sciences 76 23 2699 - 2709 2005年04月22日 [査読有り][通常論文]
     
    Osteogenesis in the teleost was morphologically observed using regenerating scales of goldfish. Histological observations indicated that osteoblasts around the regenerating scales on days 7 to 10 were greater in size and number than those at other stages. Therefore, further experiments were carried out to examine the activity of osteoblasts in the regenerating period. To quantify their osteoblastic activities, scales on the left side of the body were taken, and the regenerating scales were then used to measure the activities of alkaline phosphatase (ALP), a marker of osteoblasts, on days 7, 10, and 15. The ontogenic scales on the right side of the body were also collected and used to measure ALP activity on the same days. Osteoblasts at all stages of regenerating scales were more active than those in the remaining ontogenic scales. The regenerating scales on day 10 had the highest activity. Furthermore, we found that estrogen receptor (ER) mRNA was expressed in the regenerating scales because estrogen participates in osteoblastic growth and differentiation in mammals. Therefore, using a scale culture system reported previously, the estrogenic response was examined in the ontogenic and regenerating scales on day 10. The reactivity was much higher in regenerating scales, although estrogen treatment significantly activated the osteoblastic activities in both scales. We are the first to demonstrate that ER is expressed in regenerating scales and that estrogen participates in osteogenesis as it does in mammalian bone. Our findings strongly suggest that regenerating scales can be used as a model of osteogenesis in vertebrates. © 2005 Elsevier Inc. All rights reserved.
  • Y Takagi, H Tohse, E Murayama, T Ohira, H Nagasawa
    MARINE ECOLOGY PROGRESS SERIES 294 249 - 256 2005年 [査読有り][通常論文]
     
    In the teleost fish otolith, the alternate deposition of CaCO3-rich and protein-rich layers results in the formation of daily increments. In order to clarify the mechanism of daily increment formation, a precise understanding of the relationship between ionic and organic controls of otolith growth is essential. In the present study, we studied diel variations in the aragonite saturation rate (Sa) of the endolymph and the mRNA expression of 2 major otolith matrix proteins, OMP-1 and otolin1, in the saccular tissue. A new technique for simultaneously quantifying endolymph S,, and mRNA expression in the saccular tissue from an individual rainbow trout was developed. Endolymph Ca2+ levels, CO2 partial pressure (P-CO2) and pH were simultaneously measured using an automatic pH/gas/electrolyte analyzer, and the S. was calculated.. Total RNA was isolated from sacculi of individual fish after the endolymph was obtained. cDNAs were synthesized and used to quantify OMP-1 and otolin-1 mRNA expression levels by real-time PCR. Significant diel variations were observed in endolymph pH and P-CO2 levels in an antiphasic manner. Endolymph S, did not exhibit significant diel variations and was maintained at a value of more than 2.0, indicating that the endolymph was kept supersaturated with respect to aragonite during the day-night cycle. Expression of otolin-1 mRNA had apparent diel variations with high levels at night, whereas that of OMP-1 mRNA was almost constant. These data strongly suggest an organic control of daily increment formation in the otolith. The most probable candidate protein for daily increment formation is otolin-1.
  • Hirotoshi ENDO, Yasuaki TAKAGI, Noriaki OZAKI, Toshihiro KOGURE, Toshiki WATANABE
    Biochemical Journal 384 1 159 - 167 2004年11月15日 [査読有り][通常論文]
     
    The DD4 mRNA of the penaeid prawn Penaeus japonicus was shown previously to be expressed in the epidermis adjacent to the exoskeleton specifically during the post-moult period, when calcification of the exoskeleton took place. The encoded protein possessed a Ca2+-binding site, suggesting its involvement in the calcification of the exoskeleton. In the present study, an additional ORF (open reading frame) of 289 amino acids was identified at the 5′ end of the previous ORF. The newly identified part of the encoded protein included a region of approx. 120 amino acids that was highly rich in glutamate residues, and contained one or more Ca2+-binding sites. In an immunohistochemical study, signals were detected within calcified regions in the endocuticular layer of the exoskeleton. Bacterially expressed partial segments of the protein induced CaCO3 crystallization in vitro. Finally, a reverse transcription-PCR study showed that the expression was limited to an early part of the post-moult period, preceding significant calcification of the exoskeleton. These observations argue for the possibility that the encoded protein, renamed crustocalcin (CCN), promotes formation of CaCO3 crystals in the exoskeleton by inducing nucleation.
  • E Murayama, Y Takagi, H Nagasawa
    HISTOCHEMISTRY AND CELL BIOLOGY 121 2 155 - 166 2004年02月 [査読有り][通常論文]
     
    The fish otolith consists mainly of calcium carbonate and organic matrices, the latter of which may play important roles in the process of otolith formation. We previously identified two otolith matrix proteins, named otolith matrix protein-1 (OMP-1) and otolin-1, from the rainbow trout, Oncorhynchus mykiss, and the chum salmon, O. keta. In this study, recombinant proteins corresponding to OMP-1 and otolin-1 were synthesized using yeast and bacterial expression systems, respectively, to produce specific antibodies against each protein. Immunohistochemical analysis using these antisera revealed that in the otoliths of adult fish, OMP-1 and otolin-1 were colocalized along the daily rings possibly formed by alternate deposition of calcium carbonate and organic matrices. In the adult inner ear, OMP-1 was produced at most of the saccular epithelium, while otolin-1 was produced at a limited part of cylindrical cells located at the marginal zone of the sensory epithelium. In the embryonic inner ear, these proteins had already existed in the otolith primordia when calcification had commenced. In addition, otolin-1 was localized in the fibrous materials connecting otolith primordia and sensory epithelium at this stage. These results indicate that these proteins are required as essential components for otolith formation and calcification.
  • Vertebral deformities in cultured red sea bream, Pagrus major, Temminck and Schlegel.
    Hattori, M, Y. Sawada, Y. Takagi, R. Suzuki, T. Okada, H. Kumai
    Aquaculture Research 34 1129 - 1137 2003年10月10日 [査読有り][通常論文]
  • Okada N, Takagi Y, Tanaka M, Tagawa M
    The anatomical record. Part A, Discoveries in molecular, cellular, and evolutionary biology 273 1 663 - 668 1 2003年07月 [査読有り][通常論文]
  • Takagi Yasuaki, Tanaka Hideji, Naito Yasuhiko
    Otsuchi Marine Science 28 6 - 13 Otsuchi Marine Research Center, Ocean Research Institute, the University of Tokyo 2003年03月28日 [査読有り][通常論文]
     
    The homing season of chum salmon in the Sanriku coastal area is generally late September to January. The surface water temperature is 20℃ at the beginning of the season and decreases to 12℃ at the end. This temperature condition is very tough for the homing migration of chum salmon, since they are typical cold-water species. How do they behave in the waters where temperatures can be close to their upper lethal limit? We monitored swimming behavior of salmon using micro data-loggers to study the relationship between homing behavior and ambient temperature. Seasonal changes in seawater temperature transformed the salmon behavior from deep diving to surface swimming. The deep diving is a type of behavioral thermoregulation in thermally stratified water with high surface temperature, whereas surface swimming helps the salmon to locate their natal rivers. Sexual maturation induced the salmon to seek their natal river in the surface water, even if their temperature was high. An analysis of the vertical movements of the salmon indicated that salmon are negatively buoyant throughout the dive, and thus, the energy cost for deep diving cannot be negligible. Our data indicate the high behavioral adaptability of salmon to such thermally stratified water with high surface temperature.
  • Yasuaki Takagi
    Marine Ecology Progress Series 231 237 - 245 2002年04月22日 [査読有り][通常論文]
     
    This is the first report on the aragonite saturation state of the endolymph in a single fish species, the rainbow trout Oncorhynchus mykiss, based on the direct quantification of electrolyte concentrations in the saccular endolymph. The Ca2+ level, CO2 partial pressure and pH of the saccular endolymph in 1+ and 2+ yr old trout were simultaneously determined using an automatic pH/blood gas/electrolyte analyzer. From the values of CO2 partial pressure and pH, HCO3 - and CO3 2- levels were obtained using the Henderson-Hasselbalch equation. In addition, Na, K, Cl, Mg and inorganic P levels were measured in order to determine ionic strength of the endolymph. The aragonite supersaturation rate (Sa) was calculated from the Ca2+ and CO3 2- concentrations and the ionic strength. In both age groups, Ca2+ and CO3 2- concentrations were around 0.75 and 0.68 mmol l-1, respectively. Small differences in Na, P, and HCO3 - concentrations were observed between the 2 age groups, but endolymph ionic strength was similar. The Sa ratio was 2.885 to 3.507 in 1+ yr old fish and 2.027 to 4.303 in 2+ yr old fish. Therefore, the endolymphis supersaturated with respect to aragonite. Sa was significantly correlated with CO3 2- levels, which were largely determined by pH. As a consequence, Sa was strongly dependent on pH, indicating that endolymph pH-regulation is important in the aragonite crystallization of the otolith.
  • E Murayama, Y Takagi, T Ohira, JG Davis, MI Greene, H Nagasawa
    EUROPEAN JOURNAL OF BIOCHEMISTRY 269 2 688 - 696 2002年01月 [査読有り][通常論文]
     
    A collagen-like protein was identified from the otoliths of the chum salmon, Oncorhynchus keta. The otolith, composed mainly of calcium carbonate with small amount of organic matrices, is formed in the inner ear and serves as a part of the hearing and balance systems. Although the organic matrices may play important roles in the growth of otolith, little is known about their chemical nature and physiological function. In this study, a major organic component of the otolith, designated otolin-1, which may serve as a template for calcification, was purified. The sequences of two tryptic peptides from otolin-1 revealed high homology with parts of a saccular collagen which had been described previously [Davis, J.G., Oberholtzer, J.C., Burns, F.R. & Greene, M.I. (1995) Science 267, 1031-1034]. Cloning of a cDNA coding for otolin-1 revealed that the deduced amino-acid sequence contained a collagenous domain in the central part of the protein. Although collagen is the most abundant structural protein in the animal body, otolin-1 mRNA was expressed specifically in the sacculus. Immunohistochemical studies showed that otolin-1 is synthesized in the transitional epithelium and transferred to the otolith and otolithic membrane. This is the first report concerning characterization of a structural protein containing many tandem repeats of the sequence, Gly-Xaa-Yaa, typical for collagen from the biomineral composed of calcium carbonate.
  • Yasuaki Takagi
    Zoological Science 18 5 623 - 629 2001年07月 [査読有り][通常論文]
     
    Fish undergo a brief growth spurt known as "compensatory growth" when they resume adequate feeding after a restricted food intake. In the present study, changes in formation and resorption of acellular bone during the compensatory growth period were quantified using bone histomorphometry. Juvenile tilapia (Oreochromis niloticus) were starved for 15 days and subsequently refed for 15 days. In the starvation period, osteoblastic activity decreased linearly with time and almost reached zero on day 15, whereas the significant reduction in osteoclastic activity first became evident on day 15. This resulted in an increased percentage of eroded bone surface, which is the bone surface affected by osteoclasts. In the refeeding period, osteoblastic activity recovered to the levels of fed fish on day 3, briefly increased above the levels of fed fish on day 7, then returned to those of fed fish on day 15. Osteoclastic activity gradually increased and returned to the levels of fed fish from 7 days onwards. The eroded surface rapidly decreased to the levels of fed fish on day 3, became significantly lower than those of fed fish on day 7, and then returned to those of fed fish on day 15. It is concluded that starvation leads to a decreased turnover rate in tilapia acellular bone, which can be reversed by subsequent refeeding. A brief increase in bone-forming activity above the levels of fed fish, "the compensatory bone-formation", is a characteristic feature of the recovery period.
  • 都木 靖彰, 宮崎 信之
    地球環境 6 1 87 - 91 国際環境研究協会 2001年 [査読無し][通常論文]
  • 都木 靖彰, 乙部 弘隆, 田中 秀二
    地球環境 6 1 69 - 77 国際環境研究協会 2001年 [査読無し][通常論文]
  • F. Katoh, S. Hasegawa, J. Kita, Y. Takagi, T. Kaneko
    Canadian Journal of Zoology 79 5 822 - 829 2001年 [査読有り][通常論文]
     
    Physiological and morphological differences between killifish adapted to seawater (SW) and fresh water (FW) were examined with special reference to chloride cells. There was no difference in plasma osmolality between SW- and FW-adapted fish, reflecting their euryhalinity. A rich population of chloride cells was detected in whole-mount preparations of the gills and opercular membrane from SW- and FW-adapted fish. There was no difference between SW- and FW-adapted fish in gill Na+,K+-ATPase activity or oxygen-consumption rates. The gill chloride cells were located mostly in a flat region of the afferent-vascular edge of the filaments. In both tissues, the cells were larger in FW- than in SW-adapted fish. The apical membrane of chloride cells was invaginated to form a pit in SW-adapted fish, whereas it was flat or showed projections and was equipped with microvilli in FW-adapted fish. Chloride cells often interdigitated with neighboring accessory cells in SW-adapted fish, forming multicellular complexes. In FW-adapted fish, on the other hand, a pair of chloride cells that were similar in size was occasionally associated to form "twin cells." Thus, distinct SW and FW types of chloride cells were defined. Our findings suggest that SW- and FW-type chloride cells are equally active in the two environments, but exhibit different ion-transporting functions.
  • Hideji Tanaka, Yasuaki Takagi, Yasuhiko Naito
    Journal of Experimental Biology 204 22 3895 - 3904 2001年 [査読有り][通常論文]
     
    Although the homing migration of Pacific salmon is well documented, the swimming behaviour of the returning salmon has been poorly described, principally as a result of the difficulties encountered in monitoring salmon behaviour in the sea. The present study describes the use of a recently developed electronic data logger to obtain simultaneous recordings of the swimming speed, depth, fin-beating activity and body angle of free-ranging chum salmon Oncorhynchus keta during their homing migration in coastal waters. Chum salmon migrated horizontally at speeds of 1.5-3.0 km h-1. The gross horizontal distance salmon moved during total recording periods were 1.24- to 19.0-fold greater than the net distance from the release site to the retrieval points. It is suggested that homing salmon did not drift passively but swam actively to the spawning grounds. Salmon preferred the surface water, but also made frequent vertical migrations. The travelled depth of each salmon ranged from 0.36 to 0.64 km per hour. Salmon descended at faster rates and steeper angles than they ascended. Both tailbeat frequency and tail thrust were higher during the ascent than the descent phase. These results suggest that chum salmon spent more energy during the ascent than the descent phase. Profiles of descent rate assumed an arched shape with respect to a change in hydrostatic pressure, while ascent rate increased with decreasing depth. High tailbeat frequencies were found during the course of ascent, which suggests that the salmon did not regulate the volume of air in the swim bladder during short-term vertical migrations.
  • Nozomi Okada, Yasuaki Takagi, Tadahisa Seikai, Masaru Tanaka, Masatomo Tagawa
    Cell and Tissue Research 304 1 59 - 66 2001年 [査読有り][通常論文]
     
    The symmetrical body of flatfish larvae dramatically changes into an asymmetrical form after metamorphosis. Eye migration results in the most significant asymmetrical development seen in any vertebrate. To understand the mechanisms involved in eye migration, bone and cartilage formation was observed during metamorphosis in laboratory-reared Japanese flounder, Paralichthys olivaceus, by using whole-body samples and histological sections. Most of the hard tissues of the cranium (parasphenoid, trabecular cartilage, supraorbital canal, and supraorbital bar) exist symmetrically in the larval period before metamorphosis and develop by twisting in the same direction as that in which the eye migrates. An increase in skin thickness beneath the eye was observed only on the blind side at the beginning of eye migration this was the first definitive difference between the right and left sides of the body. The pseudomesial bar, a peculiar bone present only in flatfishes, developed from this thick skin and grew dorsad. Novel sac-like structures were found and named retrorbital vesicles. The retrorbital vesicle of the blind side grew larger and faster than that of the ocular side when the right eye moved most dramatically, whereas no difference was observed between the volume of right and left connective tissue in the head. The asymmetrical presence and growth of the pseudomesial bar together with inflation of the retrorbital vesicle on the blind side may be responsible for right eye migration during metamorphosis in the Japanese flounder.
  • T. Yada, T. Azuma, Y. Takagi
    Comparative Biochemistry and Physiology - B Biochemistry and Molecular Biology 129 2-3 695 - 701 2001年 [査読有り][通常論文]
     
    The influence of acclimation to seawater (SW) and growth hormone (GH) administration on immune functions was examined in the rainbow trout (Oncorhynchus mykiss). After 3 days acclimation to dilute SW (12 parts per thousand, ppt), an increase in plasma lysozyme activity was observed compared to the fish kept in fresh water (FW). No change was seen in plasma immunoglobulin M (IgM) levels. When they were transferred from dilute SW to full-strength SW (29 ppt) after a single intra-peritoneal injection of ovine or salmon GH, plasma sodium levels of GH-treated fish were significantly lower than those of the control fish injected with Ringer's solution 24 h after the transfer. The plasma level of IgM was not influenced by GH injection in the fish kept in FW nor in those transferred to SW. The administration of GH increased plasma lysozyme activity in the fish in FW, but no further increase was seen after SW transfer. The production of superoxide anions in peripheral blood leucocytes was stimulated by GH in both FW and SW. These results suggest that GH is involved in the stimulation of the non-specific immune functions in SW-acclimated salmonids. © 2001 Elsevier Science Inc.
  • Emi Murayama, Atsuro Okuno, Tsuyoshi Ohira, Yasuaki Takagi, Hiromichi Nagasawa
    Comparative Biochemistry and Physiology Part B: Biochemistry and Molecular Biology 126 4 511 - 520 2000年08月 [査読有り][通常論文]
  • 乙部 弘隆, 都木 靖彰, 安保 綾子
    日本水産学会誌 66 4 705 - 712 公益社団法人日本水産学会 2000年07月 [査読有り][通常論文]
     
    大槌湾をモデル海域とし, 1996年と1997年の日々の漁況と海象・気象変動データから, 三陸沿岸へ回帰したサケの行動と海象や気象変動との関係を論じた。漁獲ピーク時の水温は両年とも13℃台であった。5mm以上の降雨や10m/s以上の西風が吹いた日の直後には, 前日の1.5倍以上の漁獲がみられた日が両年とも8割あった。特に漁期で最大降雨日あるいは最大強風日の直後には一, 二の好漁であった。以上の結果はサケの遡上行動に海象・気象変動が大きく関与していることを示す。
  • Hideji Tanaka, Yasuaki Takagi, Yasuhiko Naito
    Journal of Experimental Biology 203 12 1825 - 1833 2000年06月 [査読有り][通常論文]
     
    Homing Pacific salmon are suggested to utilise directional cues in shallow water while migrating in coastal waters. Since salmonids are typical cold-water fish, they may have to cope with warm surface water while gathering directional information. We studied behavioural thermoregulation of 31 free-ranging chum salmon Oncorhynchus keta using micro data loggers off the Sanriku coast from early October to December. The surface water temperature was approximately 20°C in early October and decreased to approximately 12°C in December. The seasonal change of water temperature transformed the behaviour of salmon markedly from deep diving to shallow swimming. In October, salmon frequently dived to depths exceeding 100 m. Duration of deep dives tended to be prolonged as the thermal difference between sea surface and bottom water increased. The results indicated that salmon sought the coolest thermal refuge that they could exploit by vertical movement. Thermal refuge could be a way for salmon to minimise metabolic energy cost however, salmon repeatedly returned to the surface water column. We found a positive correlation between surface swimming of salmon and the presence of cool covering water, which could contain river waters. This suggests that salmon tend to be risk-prone when subjected to a high concentration of directional cues. Salmon in December spent most of their time in shallow water. These findings suggest that salmon adjusted their behavioural strategy with the hydrographic structure of the sea in order to achieve a balance between acquiring directional cues and behavioural thermoregulation.
  • Y Takagi, K Ishii, N Ozaki, H Nagasawa
    ZOOLOGICAL SCIENCE 17 2 179 - 184 2000年03月 [査読有り][通常論文]
     
    Gastrolith matrix protein (GAMP) is a novel protein purified from gastroliths of the crayfish, Procambarus clarkii, and has been suggested to be associated with calcium carbonate deposition. In the present study, a specific antibody against CAMP was raised and distribution of CAMP immunoreactivity was studied in crayfish gastrolith and exoskeleton. Localization of calcium carbonate in the exoskeleton, determined by silver nitrate staining and energy dispersive X-ray microanalysis, was compared with that of GAMP immunoreactivity. Crystalline forms of calcium carbonate were also determined. SDS-PAGE and Western blotting revealed that the gastrolith extract contained a major band which was GAMP-immunopositive and showed the same mobility as that of purified CAMP. The exoskeleton extract showed smear bands, but no immunoreaction was detected. By using immunohistochemistry, the anti-CAMP antiserum reacted almost uniformly with gastrolith matrix irrespective of gastrolith size. Epithelial cells of the gastrolith disc were also immunopositive. In the exoskeleton, exocuticle was strongly CAMP-immunopositive, whereas the endocuticle and membrane layer was slightly positive. The epicuticle was immunonegative. Calcium carbonate was detected in exocuticle, endocuticle and a part of the membrane layer, but not in the epicuticle. Thus, the distribution of CAMP immunoreactivity roughly corresponded with that of calcium carbonate. X-ray diffraction study showed that calcium carbonate in the gastrolith was amorphous, whereas that in the exoskeleton consisted of calcite crystals. These data indicate that a GAMP-immunoreactive substance is commonly distributed in the mineralized tissues of the crayfish, but may exist in a chemically different form in other tissues.
  • 都木 靖彰
    東京大学海洋研究所大槌臨海研究センター研究報告 25 1 - 6 The University of Tokyo 2000年03月 [査読有り][通常論文]
  • Yasuaki Takagi, Kou Ishida, Yasuo Mugiya
    Fisheries Science 66 5 933 - 939 2000年 [査読有り][通常論文]
     
    A lectin-binding assay was applied to the rainbow trout, Oncorhynchus mykiss, sacculus in order to identify specific sugars in the otolith organ. The binding of biotinylated lectins to the sagitta, otolith membrane and saccular epithelial cells was detected by histochemistry, and their binding to the EDTA-soluble fraction of the otolith matrix and saccular endolymph was detected by dot-blot analysis. N-Acetylglucosamine (GlcNAc) and mannose (Man) were identified in the otolith matrix with both techniques. These data indicate that glycoproteins in the otolith matrix have N-glycosidically linked sugar chains. In the otolith membrane, GlcNAc and Man were identified in the subcupular meshwork, whereas only Man was identified in the gelatinous layer. This is in line with the hypothesis that a part of the subcupular meshwork is incorporated into the otolith as an organic matrix. The saccular epithelial cells reacted with at least one of the lectins which bound to the otolith matrix. The endolymph had the same reactivity with lectins as the otolith matrix. Thus, we suggest that otolith-matrix carbohydrates are produced in the saccular epithelial cells, secreted into the endolymph, and deposited onto the otolith.
  • Yasuaki Takagi
    Fisheries Science 66 1 71 - 77 2000年 [査読有り][通常論文]
     
    In order to investigate the process of otolith-matrix production and deposition, ultrastructural immunolocalization of an EDTA-soluble fraction of otolith matrix (otolith soluble-matrix, OSM) was studied in the sacculus of rainbow trout, Oncorhynchus mykiss, just-hatched fry. In the transitional epithelial cells of a cylindrical type, OSM was packed in the vesicles whose diameter was 100-250 nm. In the transitional epithelial cells of a cuboidal type and squamous epithelial cells, OSM was packed into the vesicles whose diameter was 0.5-1.5 μm. Sensory epithelium was immunonegative. Exocytosis of small vesicles, dilations of translucent vesicles, and extrusions of cytoplasm were frequently associated with the apical surface of the transitional and squamous epithelial cells. The OSM-immunopositive fibrous substance existed in the endolymph and was deposited onto the otolith surface. Otolith matrix was an OSM-immunopositive fibrous substance arranged into the meshwork. Densely packed layers and less densely packed layers of the matrix were deposited alternatively. The present results indicate that OSM is produced in the transitional and squamous epithelial cells, is stored in the two types of secretory granules, is secreted into the endolymph, and is deposited onto the otolith surface.
  • Tsutsui Naoaki, Ishii Katsuaki, Takagi Yasuaki, WATANABE Toshiki, NAGASAWA Hiromichi
    Zoological science 16 4 619 - 628 社団法人 日本動物学会 1999年08月15日 [査読有り][通常論文]
     
    In the crayfish Procambarus clarkii, the gastroliths are formed as a paired structure in the stomach during the premolt period, and contain calcium carbonate and a small amount of an organic matrix. In this investigation, a cDNA encoding an insoluble matrix protein was isolated from P. clarkii. The open reading frame encoded 505 amino acid residues including two unique repeated sequences. The N-terminal half of the amino acid sequence, which included 10-amino-acid repeats, exhibited a high degree of similarity to that of involucrin, a protein synthesized in human keratinocytes. Northern blot analysis revealed that mRNA encoding the matrix protein is specifically expressed in the gastrolith discs during the premolt period in which the gastroliths formed. In the gastrolith discs, levels of expression of this mRNA correlated increases in weights of the gastroliths concomitant with their formation. Organ culture of the gastrolith discs suggested that expression of mRNA in the discs is induced by molting hormone, 20-hydroxyecdysone. These results reinforced the relationship between the matrix protein and formation of the gastroliths. Functional analysis showed that the protein inhibits calcium carbonate crystallization in a solution system, suggesting that the protein plays a role in the calcification of the gastroliths.
  • PERSSON P
    J. Fish Biol. 54 3 669 - 684 1999年03月 [査読有り]
  • Yasuaki Takagi, Akiyoshi Takahashi
    The Anatomical Record 254 3 322 - 329 1999年03月01日 [査読有り][通常論文]
  • JOHANNSSON SH.
    Ann. N. Y. Acad. Sci. 839 1 TRENDS IN COM 434 - 436 1998年05月 [査読有り][通常論文]
  • Yasuaki Takagi, Björn Thrandur Björnsson
    General and Comparative Endocrinology 108 1 80 - 86 1997年10月 [査読有り][通常論文]
  • TAKAGI Y.
    Anat.Rec. 248 4 483 - 489 1997年08月 [査読有り][通常論文]
  • Petra Persson, Sigurdur Hilmir Johannsson, Yasuaki Takagi, Bjorn Thrandur Bjornsson
    J Comp Physiol B 167 473 468 - 473 1997年 [査読有り][通常論文]
  • Y Takagi, B Th Björnsson
    Journal of Endocrinology 149 2 357 - 365 1996年05月 [査読有り][通常論文]
     
    Abstract The actions of 3,3′,5-tri-iodo-l-thyronine (T3) and recombinant human IGF-I (rhIGF-I) as well as their interaction on cartilage growth in rainbow trout (Oncorhynchus mykiss) were examined. Uptake of 3H-methyl thymidine and 35S-sulfate by isolated branchial cartilage was measured as a marker for chondrocyte proliferation and sulfated glycosaminoglycan synthesis respectively. When T3 (1·0 μg/g) was injected intraperitoneally, plasma T3 levels reached a transient peak after 1 day and decreased rapidly thereafter. Sulfate and thymidine uptake were not affected by T3 at 1 and 3 days post-injection, but at 6 days post-injection both were significantly higher in T3injected fish than those in controls. The stimulatory effects of a T3 injection on sulfate and thymidine uptake were dose-dependent over the range of 0·01, 0·1 and 1·0 μg/g. In vitro exposure of cartilage to T3 (0·075, 0·75, 7·5, 75 and 750 nm) for 6 days resulted in dose-dependent stimulation of sulfate uptake, with a maximum response at 7·5 nm and higher. T3 exposure (7·5 nm) for 2 or 3 days also increased sulfate uptake, but only slightly. Thymidine uptake was not clearly affected by T3. In vitro addition of rhIGF-I (0·075, 0·75 and 7·5 nm) increased sulfate uptake, but not thymidine uptake, dose-dependently. Compared with T3, rhIGF-I induced a greater maximum level of sulfate uptake: at 7·5 nm rhIGF-I increased the uptake 17-fold whereas T3 increased the uptake fourfold. When T3 (0·075, 0·75 or 7·5 nm) and rhIGF-I (0·1 or 1·0 nm) were added together, stimulative actions of T3 on sulfate uptake were largely additive to those of rhIGF-I. The results indicate that T3 as well as IGF-I are important modulators of sulfated glycosaminoglycan synthesis in rainbow trout cartilage. Journal of Endocrinology (1996) 149, 357–365
  • Yasuaki Takagi, Toyoji Kaneko
    Cell and Tissue Research 280 1 153 - 158 1995年04月 [査読有り][通常論文]
     
    Mineral-containing bone particles (BPs) were implanted intramuscularly into rainbow trout (Oncorhynchus mykiss) to investigate the sequence of appearance of bone-resorbing cells. A fibrous substance first surrounded the implanted BPs and was gradually replaced by connective tissue containing capillaries. Two weeks after BP implantation, relatively small multinucleated cells (type-1 cells), whose cytoplasm stained deeply with hematoxylin, appeared along the surfaces of the BPs. At later stages (after 4-8 weeks), the majority of cells which appeared to be resorbing the BPs were multinucleated cells whose cytoplasm stained deeply with eosin (type-2 cells). Type-2 cells contained more nuclei than type-1 cells. Electron-microscopical observations revealed that type-2 cells had the characteristic features of osteoclasts: the presence of numerous mitochondria, vacuoles and granules, and a differentiation of the cell membrane and cytoplasm into a ruffled border and clear zone, respectively. A tartrate-resistant acid phosphatase activity, which is an established characteristic of osteoclasts in terrestrial vertebrates, but which had not previously been examined in teleosts, was demonstrated histochemically in the type-2 cells. Development of type-2 cells was closely correlated with the development of connective tissue. These findings suggest that the development of a capillary network around the implanted BPs enables circulating osteoclast-progenitors to reach the surface of the BPs. © 1995 Springer-Verlag.
  • T. Kaneko, S. Hasegawa, Y. Takagi, M. Tagawa, T. Hirano
    Marine Biology 122 1 165 - 170 1995年03月 [査読有り][通常論文]
  • PERSSON P.
    Fish Physiol Biochem 14 329 - 339 1995年 [査読有り][通常論文]
  • TAKAGI Y
    J Exp Zool 268 3 229 - 238 1994年03月01日 [査読有り][通常論文]
  • 山野目健, 志田修, 三星亨, 徳島 暢礼, 大村禮司, 都木靖彰
    水産増殖 42 3 389 - 396 日本水産増殖学会 1994年 [査読有り][通常論文]
     
    ヒメマス, Oncorhynchus nerkaは, 0+魚, 1+魚とも春期に高い浸透圧調節能を示した。
    ヒメマスの海水移行後の浸透圧調節能に及ぼす50%海水馴致の効果を調べた結果, 海水適応能のあまり高くない時期においては浸透圧調節能を個体によっては助長するが, 海水適応能の高い春期においては, その効果は認められず, 50%海水馴致は必要としないことがわかった。
    ヒメマスにおいては, 海水移行後短期間の浸透圧ストレスの大小がその後の成長において大きな影響を及ぼし, その影響は長期にまで及ぶと考えられた。
  • TAKAGI Y.
    Comp Biochem Physiol 105 3 459 - 462 1993年07月 [査読有り][通常論文]
  • TAKAGI Y
    Comp Biochem Physiol 102 3 481 - 485 1992年07月 [査読有り][通常論文]
  • Yasuaki Takagi, Shunsuke Moriyama, Tetsuya Hirano, Juro Yamada
    General and Comparative Endocrinology 86 1 90 - 95 1992年04月 [査読有り][通常論文]
  • Takagi Yasuaki, Hirano Tetsuya, Yamada Juro
    Zoological Science 6 1 83 - 89 日本動物学会 1989年 [査読有り]
  • TAKAGI Y
    Comp Biochem Physiol, A 92 4 605 - 608 1989年01月 [査読有り][通常論文]
  • Takagi Yasuaki, Nakamura Yoshikazu, Yamada Juro
    Zoological Science 2 4 523 - 530 Zoological Society of Japan 1985年 [査読有り][通常論文]
     
    Effects of stanniectomy (CSX) on the absorption of Ca in the intestine of rainbow trout were examined by incubating the everted gut sac in Ringer solution. The serum Ca concentration increased by CSX in fish adapted to 1/3 SW but not in those adapted to FW. Ca moved from mucosa to serosa in the anterior intestine from FW-shams and the movement was not affected by CSX. The absorptive movement of Ca was not evident in 1/3 SW-shams but became apparent following CSX. Transports of water and other electrolytes (Na, Cl, K, Mg and Pi) showed no significant changes by CSX. The results indicated that the intestine is a target organ for an active principle of the CS, which are activated in a high-Ca environment to prevent Ca entry from the ambient water.

MISC

書籍等出版物

  • ウナギの科学
    塚本勝巳 (担当:共著範囲:第3章 3.2 骨格)
    朝倉書店 2019年
  • 魚類学の百科事典
    (担当:共著範囲:骨組織の形成と代謝)
    丸善出版 2018年
  • 魚類学
    矢部 衞, 桑村 哲生, 都木 靖彰 (担当:編者(編著者))
    恒星社厚生閣 2017年 377
  • マリンバイオテクノロジーの新潮流
    シーエムシー出版 2011年

所属学協会

  • （社）日本動物学会   日本水産学会   日本水産増殖学会   Zoological Society of Japan   

共同研究・競争的資金等の研究課題

  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2021年04月 -2025年03月 
    代表者 : 都木 靖彰, 浦 和寛, 東藤 正浩
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2021年07月 -2023年03月 
    代表者 : 都木 靖彰, 浦 和寛
     
    小課題1．チョウザメ脊索Ⅱ型コラーゲン（NC）を用いたⅡ型コラーゲン線維コート技術の開発： 本研究室で開発されたチョウザメ浮袋コラーゲン（SBC）を用いた線維コート技術 (Moroi et al., DOI: 10.1016/j.msec.2019.109925) を基盤としてNCの線維コート技術を開発した（線維コートとは、コラーゲン原線維を培養容器底面に一様にコーティングする技術で、生体組織のコラーゲン性基質と細胞とのインタラクションの研究を可能にする新技術である）。Ⅱ型コラーゲン溶液の濃度、線維化バッファー（リン酸バッファー）の濃度、ｐH、インキュベーション温度などを最適化することで、世界で初めてⅡ型コラーゲンの線維コートに成功した。また、マウス軟骨前駆細胞ATDC5を用いた培養試験を実施し、Ⅱ型コラーゲン分子コートと比較して線維コート上では細胞増殖速度が低下する一方で軟骨基質産生を示すアルシアンブルー染色が強陽性となる（＝前軟骨細胞から成熟軟骨細胞への分化が促進される）ことを確認した。今後軟骨細胞遺伝子発現量を定量する。 小課題2．NCを用いた3次元足場ゲルの開発： 市販のブタⅠ型コラーゲンのゲル化法を参考に、細胞毒性の低い架橋剤ゲニピンを添加することで、NCを用いてNC原線維から成るゲルとNC分子からなるゲルの合成に成功した。今後ゲルの粘弾性や細胞培養への応用技術を開発する。 小課題3．SBCもしくはNCを用いた軟骨細胞spheroid作成技術の開発： SBCを用いてマウス由来前骨芽細胞MC3T3-E1をスフェロイド化する技術を応用し、ATDC5細胞のスフェロイド化に挑戦した。しかし、MC3T3-E1がスフェロイド化する条件ではATDC5細胞はスフェロイド化しなかった。本技術開発には別のアイディアが必要であると思われる。
  • 日本学術振興会：科学研究費助成事業 挑戦的研究(萌芽)
    研究期間 : 2019年06月 -2021年03月 
    代表者 : 都木 靖彰, 柚木 俊二, 成田 武文, 畑山 博哉, 浦 和寛
     
    本研究では魚類コラーゲン（SBC）を用いることで，ミクロンレベルの大直径コラーゲン線維の成長機構を直接観察するためのAFM観察，デジタルマイクロスコープ観察技術，NaCl濃度やPB濃度によるバンドル形成と細い線維の形成の制御技術を開発した。またSBC線維，分子上の細胞の遺伝子発現を変化させる情報の入り口が細胞接着部にある可能性を示した。今後これらの技術を用いることでバンドル形成機構をさらに詳細に検証できる。また，細胞とコラーゲン線維との接着装置であるインテグリンとその後の情報伝達経路を線維と分子で比較することで，線維への接着が遺伝子発現を制御する機構の解明が実現する可能性がある。
  • 日本学術振興会：科学研究費助成事業 基盤研究(B)
    研究期間 : 2018年04月 -2021年03月 
    代表者 : 都木 靖彰, 吉田 誠一郎, 松嶋 景一郎, 柚木 俊二, 畑山 博哉, 佐伯 宏樹, 三輪 佳子
     
    水産廃棄物から得られるコラーゲンペプチド（CP）を「床ずれ」治療もしくは予防用クリームに利用することを目的に，まずCP生産の原料となる精製コラーゲンおよび高純度ゼラチンの製造技術開発をおこなった。その後，酵素を用いて製造したCPを高温高圧処理することでさらに低分子化できることを示すとともに，低分子化により抗酸化能が増すことを示した。しかし，高温高圧処理によっては皮膚線維芽細胞に対する機能性は高まらず，むしろ長時間の処理によっては細胞遊走が阻害されたりCPの細胞増殖活性化能がなくなった。これらの結果から，適度な高温高圧処理により抗酸化能が高く細胞活性化能を持つCPを合成できることを示した。
  • 日本学術振興会：科学研究費助成事業 基盤研究(C)
    研究期間 : 2017年04月 -2020年03月 
    代表者 : 佐伯 宏樹, 都木 靖彰
     
    糖修飾したシロザケ筋原線維たんぱく質は，強い抗炎症作用を示す。その効果成分が産生ペプチド画分に集中することから，本研究では，等電点分画（IEF）を活用した抗炎症ペプチドの効率的調製」を目指している。昨年度はアルギン酸オリゴ糖（AO）修飾によって得た抗炎症ペプチドをIEFに供し，そこで得た酸性ペプチド画分が，強い抗炎症作用を示すことを確認したが，その効果は消化ペプチド全体で得た作用よりも弱かった。この問題の原因解明は目標達成に欠かせないと判断し，今年度は，IEFで20分画したMfペプチド(MfP)を各々AO修飾した後，マクロファージにおけるTNT-α産生の抑制効果を調べた。すなわち，各MfP画分にAOを混合・凍結乾燥し，60℃（相対湿度75 %）で0－12時間保持してメイラード反応を介したAO修飾を行い，経時的にAO修飾ペプチド（以下MfP-AO）を得た。MfP-AOの抗炎症作用は，マウス・マクロファージ様細胞（RAW264.7）におけるTNF-α産生を抑制効果によって判断した。 【結果】MfP-AO画分は，いずれもAO修飾4時間で最大のTNF-α産生抑制効果を示したが，この作用は，酸性ペプチド画分だけではなく，塩基性画分においても観察された。この知見の獲得は，昨年度の「酸性ペプチドを対象としたAO修飾が全消化ペプチドよりも抗炎症作用が劣っていた」という現象を，「AO修飾が酸性画分以外の消化ペプチドにも抗炎症作用を付与できる」という事実から説明できることを示している。そして各MfP－AO画分を詳細に検討すると，抗炎症作用が付与されない画分も存在した。以上の結果を総合すると，IEFを用いた抗炎症ペプチドの効率的調製は，単に酸性ペプチドのみを収集するだけでは十分でなく，機能付与が可能なMf-P画分の選択が必要であることを示唆している。
  • 日本学術振興会：科学研究費助成事業 挑戦的萌芽研究
    研究期間 : 2014年04月 -2017年03月 
    代表者 : 都木 靖彰, 浦 和寛, 東藤 孝
     
    ウニ生殖巣の肥大化メカニズムを研究するツールとして，生殖巣器官培養系を確立し，これを用いて生殖巣の肥大に重要な主要卵黄タンパク質（MYP）の合成を誘起する因子を探索した。仮説としてウニ体腔液中の因子と核内受容体に結合する脂質を設定し，ウニ生殖巣が肥大した時期の体腔液および肥大したウニ生殖巣から抽出した総脂質を添加して生殖巣を培養し，MYP mRNA量を定量ＰＣＲにより測定したが，どちらも優位な変動は認められなかった。本研究期間において，ウニ生殖巣中のMYP mRNAの発現を誘起する因子の決定はできなかった。今後，MYPの合成に関与する核内受容体を特定しそのリガンドを添加する実験が必要である。
  • 日本学術振興会：科学研究費助成事業 挑戦的萌芽研究
    研究期間 : 2013年04月 -2016年03月 
    代表者 : 浦 和寛, 都木 靖彰, 井尻 成保
     
    ウニの生殖巣肥大にステロイドホルモンが関与しているか解明するために、生殖巣が小さいキタムラサキウニに給餌し生殖巣を人為的に肥大させた。給餌開始前後のウニから生殖巣を摘出し、次世代シークエンス解析によりトランスクリプトーム解析を行い、22種類の核内受容体および21種類のP450を同定した。脊椎動物に見られるステロイドホルモンをリガンドとする核内受容体は認められなかった。一方、脊椎動物においてステロイドホルモンの合成に必須のP450と相同性を持つP450遺伝子は認められなかった。さらに、生殖巣ではEcR/FXRが認められたことからウニ特有のステロイドホルモンを合成・代謝している可能性が示された。
  • 日本学術振興会：科学研究費助成事業 基盤研究(A)
    研究期間 : 2012年04月 -2016年03月 
    代表者 : 足立 伸次, 荒井 克俊, 都木 靖彰, 平松 尚志, 山羽 悦郎, 井尻 成保
     
    ロシアチョウザメおよびアムールチョウザメの未分化生殖腺（将来の卵巣または精巣）および卵巣を用いて、分子的性分化期、形態的性分化期、卵成長期および卵成熟期に発現する遺伝子を次世代シーケンサーにより網羅的に解析し、各ステージ特異的発現遺伝子を探索するとともに発現定量した。それら成果を活用し、早期性判別、早期成熟誘導、安定的良質卵生産および全雌生産技術の開発を推進した。
  • 日本学術振興会：科学研究費助成事業 基盤研究(B)
    研究期間 : 2012年04月 -2016年03月 
    代表者 : 都木 靖彰
     
    配向性の高いコラーゲンを豊富に含み再生能の高い鱗をモデルとして，非コラーゲン性基質タンパク質（NCP）が魚類コラーゲン原線維の太さや配向におよぼす機能を解析した。各種NCPのクローニング，発現解析，モルフォリノノックダウン，リコンビナントタンパク質の合成とそれを用いた抗体作成および免疫組織化学解析による機能解析と，リコンビナントとコラーゲンをハイブリッド化させた新規材料の合成に成功した。今後，このようなハイブリッド材料の生体修復材料としての機能性を調べる必要がある。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2011年 -2013年 
    代表者 : 都木 靖彰, 浦 和寛, 東藤 孝
     
    これまで、ウニの生殖巣の発達につれて生殖巣で合成・蓄積されるタンパク質（主要卵黄タンパク質 Major Yolk Protein :MYP）の遺伝子構造・発現部位が明らかにされていたが、生殖巣の発達を統御機構に関しては不明なまま残されていた。本研究では、MYPおよびGAPDH mRNA発現定量系の確立をおこなうとともに、MYPの合成を誘起する生殖腺刺激ホルモンの探索を行うための生殖巣器官培養の確立を試み、短期間の器官培養系を確立した。これにより、今後 MYP mRNA 発現量を指標に生殖の内分泌統御に関する研究が可能になる。
  • 日本学術振興会：科学研究費助成事業 基盤研究(C)
    研究期間 : 2010年 -2012年 
    代表者 : 浦 和寛, 都木 靖彰
     
    北海道はウニの主要な生産地であり、従来天然ウニを漁獲すると共に、生殖巣の発達の悪いウニを良漁場へ移植するなどの対処がなされてきた。そこで、これらのウニを養殖することで生殖巣の増大を図り、商品として有効利用する試みが行われ生殖巣の品質向上に適した餌の開発が必要とされている。養殖事業や中間育成事業を効率良く行うためには、量や品質を管理しやすい人工餌料の開発が重要である。人工餌料の開発にはウニの消化吸収能力に関する基礎的知見の集積が必須であるが、これまで殆ど行われてきていなかった。本研究では、ウニ消化酵素を精製し生化学的特性を明らかにすることを目的とした。その結果、エゾバフンウニの消化酵素はキタムラサキウニに比べ高温に弱いということが明らかになった。
  • 日本学術振興会：科学研究費助成事業 基盤研究(B)
    研究期間 : 2009年 -2012年 
    代表者 : 都木 靖彰, 生駒 俊之, 浦 和寛
     
    質量分析を用いて,鱗コラーゲンの高次配向制御に関わる可能性が高いSLRPsを同定するとともに,その遺伝子クローニングをおこなって発現部位を明らかにした。また,コラーゲン変性温度がα3鎖の量とプロリン残基水酸化率とで制御される可能性を示した。さらに,磁場内でコラーゲン線維配向構造創出をおこなって粘弾性特性,引張強度を明らかにするとともに,再線維化コラーゲンを用いて高密度の新規メソ多孔材料の開発に成功した。
  • 日本学術振興会：科学研究費助成事業 学術創成研究費
    研究期間 : 2005年 -2009年 
    代表者 : 長澤 寛道, 小暮 敏博, 都木 靖彰, 作田 庄平
     
    バイオミネラリゼーション(生物が無機鉱物を作る作用)は、それによって作られる無機鉱物(バイオミネラル)に微量に含まれる有機物によって制御されていると考えられてきた。われわれは、水棲生物の石灰化組織を材料にして石灰化を制御していると考えられる有機物を探索、精製、構造・機能解析を行った。また、石灰化組織の結晶学的特徴を電子顕微鏡解析によって明らかにし、バイオミネラルの生成を制御する多数の高分子・低分子有機化合物を発見することによって従来の考え方を実証した。
  • 日本学術振興会：科学研究費助成事業 基盤研究(B)
    研究期間 : 2006年 -2008年 
    代表者 : 都木 靖彰, 浦 和寛, 生駒 俊之
     
    ウロコのコラーゲンを用いて再生医療用人工基質の合成をめざして、生物学と材料科学の両面から研究を推進した。生物学的アプローチにより鱗形成細胞分化の分子機構、コラーゲン配向を制御する候補分子、組織ごとのコラーゲンα鎖組成を明らかにした。また、材料科学的アプローチにより、ブタ及びティラピアコラーゲン線維配向ゲルを高磁場内で実現するとともに、湿潤環境下による乾燥により10~20wt%の高密度化に成功した。
  • 日本学術振興会：科学研究費助成事業 萌芽研究
    研究期間 : 2006年 -2007年 
    代表者 : 都木 靖彰, 浦 和寛
     
    我が国の水産業において、水産無脊椎動物は重要な増養殖対象動物としての位置を占めており、種苗生産・放流や養殖が盛んに行われている種も多い。近年、日本沿岸域における水産生物資源、特に無脊椎動物の資源量は減少傾向にあることから、今後は優良品種の育種や高度で効率的な増養殖技術の開発が必要になると考えられるが、水産無脊椎動物においてそのような試みは著しく立ち遅れている。その大きな理由として、水産無脊椎動物の成長や成熟を制御する内分泌系に関する基礎的知見が極めて少ないといえる。比較的研究されているウニでも、糖質・脂質・タンパク質の代謝を制御する内的因子(ホルモンなど)の存在の有無や、それらの作用機序について正確に把握されていないのが現状である。本研究は、ウニをモデル生物として選定し、無脊椎動物の内分泌機構の解明に着手するものである。 今年度は、エゾバフンウニ消化器官において、モルモット抗ブタインスリン抗血清を用いて免疫組織化学的解析を行った。その結果、胃において消化管内腔側の上皮細胞の小さな顆粒に陽性反応が認められた。また、卵巣、精巣、放射神経にも免疫陽性反応が認められた。このことからエゾバフンウニにインスリン様物質が局在している可能性が示された。
  • 日本学術振興会：科学研究費助成事業 基盤研究(C)
    研究期間 : 2004年 -2005年 
    代表者 : 清水 幹博, 都木 靖彰, 尾島 孝男, 浦 和寛
     
    ウニは北海道において重要な漁業資源であるが、それらの天然資源は減少している。そのため、養殖システムの開発が重要となってきている。そのためには栄養吸収機構を理解する必要があるが、基礎的な生理学的知見が少ない。そこで本研究では、ウニの栄養吸収機構の基礎的知見得ることを目的とし、以下の知見を得た。 1.エゾバフンウニを用いて、消化器官(咽頭、食道、胃、腸、直腸)における組織観察を行った。その結果、咽頭と食道ではこれまで1種類の顆粒細胞の存在が報告されていたが、本研究により少なくとも2種類の顆粒細胞が存在していることが明らかとなった。 2.キタムラサキウニ消化管由来のアルカリセリンプロテアーゼ(SUPase)のcDNAおよび構造遺伝子をクローニングした。SUPaseのアミノ酸配列は、スブチラーゼに属する他の酵素の触媒領域と33-46%の同一性を示すこと、さらに、Asp-His-Serからなる荷電リレーを構成するアミノ酸も良く保存されていることから、SUPaseはスブチラーゼに分類されるプロテアーゼであることが明らかになった。 3.キタムラサキウニ消化管由来のセルラーゼ(SnEG54)のcDNAをクローニングした。SnEG54のアミノ酸配列をGHF9に属するセルラーゼである、シロアリ、ホヤ、アワビの触媒ドメインのアミノ酸配列と比較したところ、51-57%の相同性を示した。
  • 日本学術振興会：科学研究費助成事業 萌芽研究
    研究期間 : 2004年 -2005年 
    代表者 : 都木 靖彰, 浦 和寛
     
    1.昨年にひきつづき、キンギョの鱗再生にともない発現するRunx2(Cbfa1)およびBMP2,4遺伝子の塩基配列決定をおこなった。Runx2は4種のアイソフォームの全塩基配列を決定した。BMP2はほぼ70%程度の配列の決定を終えた。キンギョRunx2遺伝子はこれまでに報告されたゼブラフィッシュRunx2bと最も高い相同性(約90%)を示した。BMP2および4のcDNA断片はゼブラフィッシュBMP2および4と高い相同性を示した。 2.鱗有機基質の主成分であるキンギョI型コラーゲンα鎖cDNA塩基配列を決定した。3種のα1(I)cDNA(α1(I)-A,B,C)を得、α1(I)-Aはその全塩基配列を、α1(I)-B,Cはその70%を決定した。α2(I)も3種のcDNAを得、それらの全塩基配列を決定した。α3(I)は1種類の全塩基配列を決定した。キンギョα鎖は、ゼブラフィッシュα鎖と約90%、哺乳類のα鎖と約70%の相同性を示した。また、分子系統樹ではα3(I)がα1(I)から分岐していることが確認された。さらに、既報の脊椎動物I型コラーゲンα鎖のPro残基数とコラーゲン変性温度の関係を近似式で表し、Y=0.3853X-44.712(r=0.9916)を得た。ここで、Y:変成温度(℃)、X:アミノ酸1000残基あたりのPro残基数である。この式を用いてキンギョのコラーゲンの変成温度を推定したところ、変成温度は三量体を構成するα鎖の組成で異なり、α3(I)鎖を多く含むと変成温度が高くなることが示された。 3.低リン・低カルシウム条件下におかれたキンギョの再生鱗の有機基質の微細構造解析をおこなった。リン酸カルシウム結晶は、非コラーゲン性有機基質の電子密度の高い物質中で形成され、成長することを明らかにした。
  • 日本学術振興会：科学研究費助成事業 基盤研究(B)
    研究期間 : 2003年 -2005年 
    代表者 : 都木 靖彰, 新井 崇臣, 阿部 周一, 山羽 悦郎
     
    欧米諸国における魚類の耳石微量元素研究では、誘導結合プラズマ質量分析装置(ICPMS)が用いられているが、我が国では感度の低い電子線プローブマイクロアナライザー(EPMA)が用いられている。当該研究は従来のEPMA法による耳石微量元素測定と生活履歴解析、DNAマーカーを用いた集団判別研に加え、我が国で初めてのICPMSを用いて魚類の生活履歴解析および集団判別をおこない、以下の成果を得た。 1.ICPMSよる耳石微量元素測定技術開発およびそれを利用した魚類の生活履歴解明と集団判別:ICPMSを用いた耳石および貝殻中の微量元素含有量測定法を開発し、微量元素組成による集団判別が養殖魚介類の産地判別に有効であることを示した。 2.EPMA法による耳石微量元素測定を利用した魚類の生活履歴解明:EPMAによる耳石SrおよびCa含有量測定と、Sr : Ca比を用いて、サケ科魚類やウナギ属魚類の個体の生息水域の変化(回遊経路)を詳細に明らかにした。 3.遺伝子を用いた集団判別:シロサケの系群解析を可能とするDNAマイクロアレイ方を開発した。本法は正確で時間もかからず、DNAシーケンサーなどの特別な機器を必要としないため、フィールドや調査船上における系群解析に極めて有効である。 4.耳石の形成と石灰化機構および微量元素取り込み機構の解明と魚類の他硬組織との比較:耳石有機基質OMP-1およびotolin1が日周輪形成に重要な役割を果たしていることを示すとともに、内リンパ液の過飽和度(Sa)は常に1以上に保たれ、アラゴナイト結晶形成は常に起こりうる状態に保たれてることを示した。また,サクラマスの場合では、海水移行後、耳石のSr含量が上昇するのに少なくとも7日のタイムラグがあることを初めて示した。このことは、耳石中のSrとCaの含有比より魚類の生活塩分履歴解析を行う上で考慮するべき重要な点である。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 2001年 -2004年 
    代表者 : 宮崎 信之, 乙部 弘隆, 天野 雅男, 新井 崇臣, 田辺 信介, 内藤 靖彦, 都木 靖彰
     
    本研究では、海棲哺乳類(イルカ、アザラシなど)の生活を理解する上で重要な要素である分布、回遊、成長、繁殖、食性、個体群判別などについて優れた成果をあげてきた。同時に、有機塩素系化合物(OCs)、有機スズ化合物(BTs.)、重金属類、放射性核種などの有害化学物質の生物濃縮特性を明らかにすると共に、その生物影響について国際的に注目される成果をあげてきた。その成果は、国内外の学会や講演会などで発表(英語:38回、日本語:39回)すると共に、レフリー付き学術論文(英文:88編、和文:4編)、著書(英文1編)、総説他(英文:4編、和文:19編)などに公表してきた。 なかでも、イシイルカの有機塩素系化合物、有機スズ化合物、重金属類の蓄積特性に関する研究、およびカスピカピカイアザラシ、バイカルアザラシ、北極海のワモンアザラシがA型インフルエンザウイルスに感染していたことを明らかにした研究は、ともに世界的に高い評価を得ている。特に、1979年にタイのバンコックを中心に世界的に流行したA型インフルエンザウイルス(H3N2)が現在でもカスピカイアザラシの体内に保持されていることは、人間の世界で起きている感染症を考える際に、野生動物研究との連携が極めて重要であることを示唆した。また、海洋生態系における主要な海洋生物の生活史や環境応答に関する研究成果と比較することによって、海棲哺乳類が海洋生態系で果たす役割とその特性がより鮮明になってきた。特に、カスピ海に生息するカスピカイアザラシとその餌生物との関係やチョウザメの回遊履歴との関係の研究は国際的に注目されている。甲殻類のワレカラ類で得られた有機スズ化合物による生物影響との比較は、それぞれの有害化学物質の挙動の特性をより明確にした。 今後は、本研究成果を生かして、有害化学物質による海洋汚染の環境モニタリング研究を海洋生態系全体で実施できるような研究体制を構築していく必要がある。
  • 日本学術振興会：科学研究費助成事業 基盤研究(C)
    研究期間 : 2001年 -2002年 
    代表者 : 都木 靖彰
     
    1.耳石基質タンパク産生細胞の特定と、基質タンパクの微細分布:ニジマスの耳石の主要な基質タンパク二種(OMP-1およびOtolin-1)に対する特異抗体を作成し、光顕・電顕免疫組織化学をおこない、ニジマス内耳におけるOMP-1産生細胞は扁平上皮細胞と移行上皮細胞の一部、Otolin-1産生細胞は感覚上皮細胞に接する円筒形の背の高い細胞であることを明らかにした。さらに、OMP-1が耳石にのみに含まれるのに対し、Otolin-1は耳石と耳石膜ゼラチン層の両方に含まれることを明らかにした。また、耳石基質が厚いシート状の基質とその間の微細な網目状の基質の二種類からなること、網目状の基質の密度の濃淡により日周輸が形成されること、OMP-1,Otolin-1ともに微細な網目状基質内に分布すること、したがって両基質の産生・沈着量の日周変動により日周輸が形成される可能性があることを明らかにした。 2.耳石基質タンパク遺伝子発現定量系の開発:リアルタイムPCR法を用いて、ニジマスの個体ごとに両タンパク質のmRNA発現量を定量するための技術開発をおこない、ニジマス個体ごとのOMP-1,Otolin-1発現量の定量法を確立した。現在、本法を用いて量基質タンパク遺伝子の発現の日周変動を調べている。 3.内リンパ液の過飽和度の測定:耳石は内リンパ液から析出した炭酸カルシウム結晶である。一般に水溶液から結晶が析出する場合、結晶の形態や成長速度は、溶液の過飽和度(Sa)に大きく依存する。ニジマス内耳小嚢の内リンパ液の電解質濃度を個体ごとに実測し、内リンパ液のSaは2.027-4.303の範囲にあり、内リンパ液はアラゴナイトに対して過飽和状態にあることを明らかとした。さらに、Saは内リンパ液のpHと強い相関関係があり、内リンパ液のpH調節がアラゴナイト結晶の成長(=耳石成長)に非常に重要であることを示した。
  • 日本学術振興会：科学研究費助成事業 基盤研究(B)
    研究期間 : 1999年 -2000年 
    代表者 : 内藤 靖彦, 都木 靖彰, 上田 宏, 田中 秀二, 加藤 明子, 飯郷 雅之, 小達 恒夫, 會田 勝美
     
    1999年には、岩手県大槌湾において、沿岸域で回帰回遊中の2個体のサケ(Oncorhynchus keta)から、遊泳度・遊泳深度とともに、体軸角度とTail-beat activityの約2日間にわたる記録を、装着型のマイクロデータロガーによって得ることに成功した。同様の記録は海洋を自由に遊泳する魚類からはこれまでにまったく得られたことがなく、価値の高い成果をあげることができた。本研究の結果、サケは上昇時に下降時と比べて遊泳によるエネルギーをより多く消費していること、鰾内の空気の容量を短期的にはほとんどまったく調整していないことが明らかになった。 2000年7月には、ベーリング海中央部から、27個体のサケに遊泳速度・遊泳深度・経験水温記録計を装着して放流した。現在までに、ただ1個体(放流地点56°30′N,179゜00′E)のデータロガーが回収され(再捕地点:北海道根室沿岸)、51日間のデータを得ることができた。サケの水平方向の移動速度は平均で36.2km/dayであった。したがってサケの総移動距離は2427kmと推定されるが、この推定値は、放流地点から再捕地点までの水平距離2760kmの約80%に相当することが明らかとなった。 日光中禅寺湖においては、1999年秋の予備調査を経て、2000年秋の調査では、計30個体のヒメマスにマイクロデータロガー装着放流し、23個体の経験水温と遊泳深度のデータを得ることができた。本調査では放流と再捕と同時に血液のサンプリングを行ない、血中のホルモン濃度の測定を行なうことにより、調査個体を、未排精雄、排精雄、未排卵雌、排卵雌のグループに正確に分別できることが可能になった。本調査の結果によって、ヒメマス(Oncorhynchus nerka)の成熟状態によってどのように遊泳深度が変化していたかについて解析を進めることが可能になった。
  • 日本学術振興会：科学研究費助成事業 奨励研究(A)
    研究期間 : 1999年 -2000年 
    代表者 : 都木 靖彰
     
    耳石に刻まれる日周輪やチェックリング読みとりの正確性を増し、さらなる情報を解読するためには、内耳内リンパ液の微量採取法、イオン組成測定法、耳石有機基質産生活性測定法を確立し、それらが日周輪・チェックリング形成に果す役割を解明することが必要である。 昨年度に確立した方法を用いて、ニジマスの内リンパ液のイオン組成と炭酸カルシウムアラゴナイトに対する過飽和度を求め、内リンパ液の過飽和度とpH、二酸化炭素分圧、炭酸イオン濃度、Caイオン濃度との関係を解析した。その結果、過飽和度は内リンパ液のpHに比例していることを明らかにした。このことは、内リンパ液のpHの調節により耳石成長量が調節されていることを示す。現在この成果について学術論文を執筆中である。 次に、ストレスとチェックリング形成との関係を明らかにする目的で、追い回しストレスが内リンパ液イオン組成に与える影響を調べた。短時間の追い回しストレスは血液の酸性化を引き起こしたが、内リンパ液のイオン組成、過飽和度には大きな変化がなかった。このことから、短時間のストレスはチェックリング形成の原因とならないものと結論できた。現在、繰り返しストレス、長時間のストレスの影響を調べている。 OMP-1は、我々のグループが世界に先駆けてその構造を明らかにした、耳石の可溶性有機基質であり、その成果を学術雑誌に論文として発表した(裏面参照)。また、現在OMP-1遺伝子発現量を競合PCR法を用いて調べている。 さらに、耳石有機基質の性質とその産生機構を明らかにする目的で、OMP-1の電顕的分布を調べるとともに、耳石に含まれる糖成分の解析を行った。これらの成果も学術雑誌に論文として発表した(裏面参照)。 以上の成果をまとめる目的で、耳石形成機構に関する二つの総説を学術雑誌に発表した(裏面参照)。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 1997年 -2000年 
    代表者 : 宮崎 信之, 天野 雅男, 乙部 弘隆, 都木 靖彰, 田辺 信介, 竹内 一郎
     
    本研究では、海棲哺乳動物の生活史(分類、成長、繁殖、行動、食性など)のデータをもとに合理的な資源管理を模索するとともに、海棲哺乳類を指標とした有害化学物質(有機塩素系化合物、有機スズ化合物、重金属類など)による海洋汚染のモニタリング研究を実施した。特に、有害化学物質による生息環境の汚染は、海棲哺乳類の繁殖や生存に影響を与えることから、その生物影響についても言及した。本研究課題で得られた研究成果をもとに学術論文37編、報告書・総説36編を発表すると同時に、国内外の学会発表49回、および一般講演28回を行った。イシイルカ、バイカルアザラシ、カスピカイアザラシに関する生活史研究と彼らを指標とした環境モニタリング研究は国際的にも高い関心を持たれている。なかでも、イシイルカが餌生物のバイオマスの変化に応じて主要な餌生物の種類をスイッチさせている現象を明らかにした論文は、国際的評価が高い。バイカル湖に生息しているバイカルアザラシの生活史を正確な年齢査定の方法を用いて解析した論文は、国内外の研究者からも注目されている。同時に、バイカルアザラシを通じてバイカル湖の環境汚染を推察し、バイカル湖南部のパルプ工場排水がバイカル湖を汚染し、バイカルアザラシの生存を危うくしているとの私たちの調査結果は、世界の人々に驚きをもって受け入れられた。また、カスピカイアザラシを指標としたカスピ海における環境汚染の研究は、国際的に注目されている。平成11年12月にマウイで開催された国際海棲哺乳学会では「カスピカイアザラシの危機」、平成12年4月に国立マレーシア大学で開催された「内分泌攪乱化学物質の国際会議」では「海棲哺乳類の生活史に基づいた有害化学物質の蓄積特性」、平成12年5月に開催されたUNESCO主催の会議「カスピ海とその周辺域の環境」では「カスピカイアザラシの生活史特性値と有害化学物質の蓄積特性」、平成13年3月に日本で開催された日米専門家による「内分泌化学物質の汚染とその環境評価に関する会議」では「海棲哺乳類に蓄積する有機塩素系化合物とその生物影響」を紹介した。このように、本研究課題で得られた知見をもとに、さまざまな国際会議で招待講演を行ってきた。これらの活動を通じて、海洋環境に配慮した新しいタイプの資源管理システム確立の重要性を説くとともに、彼らの生息環境の保全の必要性を国内外にアピールしてきた。
  • 日本学術振興会：科学研究費助成事業 奨励研究(A)
    研究期間 : 1997年 -1998年 
    代表者 : 都木 靖彰
     
    硬骨魚類の耳石は、年齢、日齢査定形質として水産学研究に必要不可欠な硬組織である。にもかかわらず、年輪・日周輪形成メカニズムはいまだに解明されていない。本研究は,耳石日周輪形成メカニズムを、主に耳石有機基質の産生メカニズムから解明しようとするものである。本年度は昨年度に引き続き、以下の諸点を明らかにした。 1. 抗耳石可溶性基質抗体を用いた透過型電顕組織化学を昨年に引き続き行い、移行上皮細胞・扁平上皮細胞における耳石可溶性基質産生機構およびその耳石への取り込み機構を明らかにした。可溶性基質は産生後、移行上皮細胞では小型の、扁平上皮細胞ではより大型の分泌小胞中に保存された後、エクソサイトーシスにより内リンパ液中へと分泌される。分泌された可溶性基質が内リンパ液中から耳石へと取り込まれていく様子も観察された。 2. 小嚢上皮・耳石のレクチン組織化学法および、耳石可溶性基質・内リンパ液のドットプロット法により、小麦胚芽、コンカナバリンAおよびインゲンマメレクチンに反応するN一結合型糖鎖を含む物質が感覚細胞および支持細胞から耳石膜を介して、あるいは移行上皮細胞および支持細胞から内リンパ液を介して耳石に取り込まれることを明らかにした。 3. ニジマス耳石割断面を走査型電子顕微鏡で詳細に観察したところ、小石状、平板状、球状など様々な結晶構造が観察された。現在、これらの構造がすべてあらゴアナイトからできているのか、他の結晶系(カルサイトなど)が混在しているのか、X線回折を行うべくサンプルを準備中である。それと平行して耳石可溶性基質抗体を用いた免疫組織化学を走査型電顕上で行うべく技術開発中である。 以上の結果は、タンパク質に加えて糖質、たぶん糖タンパク質が耳石形成に重要な機能を果たしていることを示唆する。今後耳石基質タンパク質や糖鎖の構造を明らかにし、その機能を解明する必要がある。
  • 日本学術振興会：科学研究費助成事業 奨励研究(A)
    研究期間 : 1996年 -1996年 
    代表者 : 都木 靖彰
     
    耳石は耳石特有の有機基質に炭酸カルシウムが沈着して生長するとされる。本研究は、糖と特異的に結合するレクチンを用いて耳石有機基質の糖構造の決定、その産生細胞の特定および産生機構の解明を目的として行われた。材料としてニジマスの最も大きい耳石(扁平石)を包む内耳膜迷路である小嚢を用いた。研究結果の概要は以下の通りである。 1.透過型電子顕微鏡観察により、小嚢上皮細胞を感覚細胞、支持細胞、移行上皮細胞、Mitochondria-rich cell(MRC)、扁平上皮細胞に分類した。MRCを除くすべての細胞が分泌活性を有するタンパク合成細胞であり、耳石形成に関与することを示唆した。 2.MRCは、その微細構造はイオン輸送生細胞の特徴を有し、代表的なイオンポンプであるNa^+,K^+-ATPaseを高濃度に持つことを証明した。このことから、MRCは小嚢内リンパ液の特殊なイオン組成の形成にあずかるイオン輸送性細胞であると断定した。 3.アルシアンブルー。PAS染色により、耳石には主として産生多糖類が、耳石膜には酸性多糖と中性多糖両方が含まれることを明らかとした。小嚢上皮のレクチン組織化学染色により、感覚上皮・移行上皮・扁平上皮細胞にはマンノース・N-アセチルグルコサミンが、支持細胞にはマンノースが含まれることを証明した。一方、ガラクトースやN-アセチルガラクトサミンが小嚢上皮に含まれる可能性は低いことを解明した。耳石抽出物を電気泳動・ウェスタンブロッティング後、レクチン(ConA)染色したところ、耳石基質タンパクの主要な成分はマンノースを含む糖タンパクであった。同様の成分は内リンパ液中にも存在した。これらのことから、小嚢上皮に含まれるマンノースの少なくとも一部は耳石基質タンパクと結合した後内リンパ液中に分泌され、耳石中に取り込まれることを示唆した。
  • 日本学術振興会：科学研究費助成事業
    研究期間 : 1994年 -1996年 
    代表者 : 宮崎 信之, 田辺 信介, 天野 雅男, 都木 靖彰, 竹内 一郎, 乙部 弘隆
     
    本研究では、海棲哺乳類を海洋汚染の指標生物として、日本近海は勿論のこと、熱帯・温帯海域から北極・南極海に至るまで広範囲に調査した。なかでも、1987-88年に多数のアザラシが死亡したバイカル湖およびその周辺域については、ロシア科学アカデミー湖沼学研究所との共同研究として実施することができ、貴重な研究成果を得ることができた。これらの研究成果については、関連学会などで発表すると同時に、一部については学術論文として公表した。その内訳は、原著論文が10編、著書が6編、報告書等が14編、講演発表が35回であった。 上記の10論文では、(1)日本のみならず世界の海に生息しているイルカ類に蓄積する有機塩素系化合物とその生物影響、(2)多数の個体が死亡したバイカルアザラシとその生息環境に存在する有機塩素系化合物とその特性、(3)日本近海に生息するイルカ類に蓄積する有機スズ類とその特性、(4)南極海に生息するアデリーペンギンに蓄積する重金属とその特性などの研究成果を中心にまとめた。同時に、これらの科学的知見をもとに地球規模の海洋汚染の現状を分析し、将来、益々厳しくなる地球規模の海洋汚染に対する対応策を検討し、国際的な監視体制の確立、国際的な標本バンクの設立、国際共同研究体制の構築などについても言及した。
  • 日本学術振興会：科学研究費助成事業 奨励研究(特別研究員)
    研究期間 : 1989年 -1990年 
    代表者 : 都木 靖彰

産業財産権

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