研究者データベース

沖野 龍文(オキノ タツフミ)
地球環境科学研究院 統合環境科学部門 環境適応科学分野
教授

基本情報

所属

  • 地球環境科学研究院 統合環境科学部門 環境適応科学分野

職名

  • 教授

学位

  • 博士(農学)(東京大学)

ホームページURL

ORCID ID

J-Global ID

研究キーワード

  • 海洋天然物化学   天然物化学   化学生態学   Marine Biotechnology   Chemical Ecology   Natural Product Chemistry   

研究分野

  • ライフサイエンス / 水圏生命科学
  • ナノテク・材料 / 生体化学
  • ナノテク・材料 / 生物分子化学

所属学協会

  • マリンバイオテクノロジー学会   米国生薬学会   米国化学会   日本比較内分泌学会   日本農芸化学会   日本水産学会   日本化学会   有機合成化学協会   日本薬学会   ASP   ACS   

研究活動情報

論文

  • Takafumi Ishikawa, Kenji Washio, Kensuke Kaneko, Xiao Rong Tang, Masaaki Morikawa, Tatsufumi Okino
    Applied Phycology 3 1 120 - 131 2022年12月31日
  • Chin-Soon Phan, Jakia Jerin Mehjabin, Andrea Roxanne J. Anas, Masahiro Hayasaka, Reiko Onoki, Juting Wang, Taiki Umezawa, Kenji Washio, Masaaki Morikawa, Tatsufumi Okino
    Journal of Natural Products 2022年08月10日
  • A Takeuchi, T Higuchi, M Kuroki, S Watanabe, MJ Miller, T Okino, T Miwa, K Tsukamoto
    Marine Ecology Progress Series 2022年
  • Chin-Soon Phan, Kenichi Matsuda, Nandani Balloo, Kei Fujita, Toshiyuki Wakimoto, Tatsufumi Okino
    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 143 27 10083 - 10087 2021年07月 [査読有り]
     
    Guanidine prenylation is an outstanding modification in alkaloid and peptide biosynthesis, but its enzymatic basis has remained elusive. We report the isolation of argicyclamides, a new class of cyanobactins with unique mono- and bis-prenylations on guanidine moieties, from Microcystis aeruginosa NIES-88. The genetic basis of argicyclamide biosynthesis was established by the heterologous expression and in vitro characterization of biosynthetic enzymes including AgcF, a new guanidine prenyltransferase. This study provides important insight into the biosynthesis of prenylated guanidines and offers a new toolkit for peptide modification.
  • Aya Takeuchi, Takatoshi Higuchi, Shun Watanabe, Michael J. Miller, Ritsuno Yama, Tatsuhiro Fukuba, Akihiro Okamura, Tatsufumi Okino, Tetsuya Miwa, Katsumi Tsukamoto
    FISHERIES SCIENCE 87 3 339 - 352 2021年05月 [査読有り]
     
    The spawning area of the Japanese eel is located at the southern part of the West Mariana Ridge in the western North Pacific, but their spawning events have not been observed. To further understand Japanese eel spawning ecology, an interdisciplinary research survey by the R/V NATSUSHIMA (NT14-09, 14 May-4 June 2014) was conducted to detect spawning sites based on the seamount, salinity front, new moon and third quadrant (spawning south of front, west of ridge) hypotheses. Attempts were made to film spawning events with underwater camera systems and to consider if eels might be detected in hydroacoustic observations. Although no Japanese eels or spawning events were video-recorded and no eel aggregations could be clearly identified acoustically, three eggs were collected at two stations in the third quadrant region at or just south of 13 degrees N on 26 and 27 May. Three or four days later, newly hatched preleptocephali were collected at two stations far to the south, including 224 at a station > 160 km southwest of the egg catches, and a few preleptocephali were caught at two stations closer to the egg stations. The eggs and southern preleptocephali were from discrete spawning events, which indicated that at least two spawning sites occurred in May 2014.
  • Imam Fathoni, Julie G. Petitbois, Walied M. Alarif, Ahmed Abdel-Lateff, Sultan S. Al-Lihaibi, Erina Yoshimura, Yasuyuki Nogata, Charles S. Vairappan, Eti Nurwening Sholikhah, Tatsufumi Okino
    MOLECULES 25 17 2020年09月 [査読有り]
     
    Cyanobacteria are reported as rich sources of secondary metabolites that provide biological activities such as enzyme inhibition and cytotoxicity. Ten depsipeptide derivatives (lyngbyabellins) were isolated from a MalaysianMoorea bouilloniiand a Red SeaOkeaniasp.: lyngbyabellins G (1), O (2), P (3), H (4), A (7), 27-deoxylyngbyabellin A (5), and homohydroxydolabellin (6). This study indicated that lyngbyabellins displayed cytotoxicity, antimalarial, and antifouling activities. The isolated compounds were tested for cytotoxic effect against human breast cancer cells (MCF7), for antifouling activity againstAmphibalanus amphitritebarnacle larvae, and for antiplasmodial effect towardsPlasmodium falciparum. Lyngbyabellins A and G displayed potent antiplasmodial effect againstPlasmodium, whereas homohydroxydolabellin showed moderate effect. For antifouling activity, the side chain decreases the activity slightly, but the essential feature is the acyclic structure. As previously reported, the acyclic lyngbyabellins are less cytotoxic than the corresponding cyclic ones, and the side chain increases cytotoxicity. This study revealed that lyngbyabellins, despite being cytotoxic agents as previously reported, also exhibit antimalarial and antifouling activities. The unique chemical structures and functionalities of lyngbyabellin play an essential role in their biological activities.
  • Jakia Jerin Mehjabin, Liang Wei, Julie G. Petitbois, Taiki Umezawa, Fuyuhiko Matsuda, Charles S. Vairappan, Masaaki Morikawa, Tatsufumi Okino
    Journal of Natural Products 83 6 1925 - 1930 2020年05月20日 [査読有り][通常論文]
  • Takashi Kamada, Chin-Soon Phan, Tatsufumi Okino, Charles Santhanaraju Vairappan
    Planta Medica International Open 6 02 e36 - e40 2019年11月 [査読有り]
     
    AbstractRed algae of the genus Laurencia have been known to produce a wide array of bioactive secondary metabolites. Here, we report the isolation of two new halogenated chamigrenes, lauremantanones A (1) and B (2), along with seven known compounds, dendroidiol (3), (+)-elatol (4), cartilagineol (5), obtusol (6), (+)-laurencenone B (7), 2-chloro-3-hydroxy-α-chamigren-9-one (8), and puertitol A (9), from a population of Laurencia majuscula (Harvey) Lucas from Mantanani Island (North Borneo). The structures of the two new metabolites were determined based on spectroscopic data (IR, 1D and 2D NMR, and MS). Compounds isolated from this alga exhibited potent cytotoxic (HeLa, MCF-7, P-388) and antibacterial (against antibiotic-resistant clinical bacteria) activities. The major metabolite of this population has significant importance in the geographical distribution of this species globally.
  • Sultan Semran Al-Lihaibi, Ahmed Abdel-Lateff, Walied Mohamed Alarif, Hajer Saeed Alorfi, Yasuyuki Nogata, Tatsufumi Okino
    Journal of Chemistry 2019 1 - 15 2019年10月30日 [査読有り]
     
    Seventy-one marine organisms representing different classes of marine fauna and flora were collected from the Red Sea. They include sponges, hydrozoan, soft corals, sea cucumber, ascidian, cyanobacteria, and macroalgae. The methanolic extracts were evaluated for their toxicity and settlement inhibition effects by using cultured Balanus amphitrite. Thirty-three extracts displayed antifouling effects: four samples were highly potent at 1 μg/mL with a percentage of settlement inhibition above 31%, twenty-two were potent at 10 μg/mL with a percentage of settlement inhibition between 16 and 30%, and seven were active at 10 μg/mL with a percentage of settlement inhibition between 0 and 15%. Two promising extracts were purified by employing several chromatographic techniques, leading to the isolation of 12 known compounds. The isolated compounds were evaluated for their antifouling activities and demonstrated potent antifouling effects with EC50 values of less than 10 μg/mL.
  • Hoshino Masakazu, Okino Tatsufumi, Kogame Kazuhiro
    JOURNAL OF PHYCOLOGY 55 1 204 - 213 2019年02月 [査読有り][通常論文]
     
    In isogamous brown algae, the sexuality of populations needs to be tested by laboratory crossing experiments, as the sexes of gametophytes are morphologically indistinguishable. In some cases, gamete fusion is not observed and the precise reproductive mode of the populations is unknown. In the isogamous brown alga Scytosiphon lomentaria in Japan, both asexual (gamete fusion is unobservable) and sexual populations (gamete fusion is observable) have been reported. In order to elucidate the reproductive mode of asexual populations in this species, we used PCR-based sex markers to investigate the sex ratio of three asexual and two sexual field populations. The markers indicated that the asexual populations consisted only of female individuals, whereas sexual populations are composed of both males and females. In culture, female gametes of most strains from asexual populations were able to fuse with male gametes; however, they had little to no detectable sexual pheromones, significantly larger cell sizes, and more rapid parthenogenetic development compared to female/male gametes from sexual populations. Investigations of sporophytic stages in the field indicated that alternation of gametophytic and parthenosporophytic stages occur in an asexual population. These results indicate that the S. lomentaria asexual populations are female populations that lack sexual reproduction and reproduce parthenogenetically. It is likely that females in the asexual populations have reduced a sexual trait (pheromone production) and have acquired asexual traits (larger gamete sizes and rapid parthenogenetic development).
  • Takeuchi Aya, Watanabe Shun, Yamamoto Satoshi, Miller Michael J, Fukuba Tatsuhiro, Miwa Tetsuya, Okino Tatsufumi, Minamoto Toshifumi, Tsukamoto Katsumi
    MARINE ECOLOGY PROGRESS SERIES 609 187 - 196 2019年01月17日 [査読有り][通常論文]
  • In vitro cytotoxic anticancer potential of bioactive fraction isolated from Indonesian tidal sponge Calthropella sp.
    Fitria Susilowti, Respati Tri Swasono, Tatsufumi Okino, Winarto Harya
    Asian Journal of Pharmaceutical and Clinical Research 12 1 380 - 383 2019年 [査読有り][通常論文]
  • Taiki Umezawa, Nurcahyo Iman Prakoso, Miho Kannaka, Yasuyuki Nogata, Erina Yoshimura, Tatsufumi Okino, Fuyuhiko Matsuda
    Chemistry & biodiversity 16 1 e1800451  2019年01月 [査読有り][通常論文]
     
    Omaezallene derivatives (nor-bromoallene, nor-bromodiene, and bromoenynes) were successfully synthesized. Their antifouling activity and toxicity to the cypris larvae of the barnacle Amphibalanus amphitrite and ecotoxicity to the marine crustacean Tigriopus japonicus were studied. It was revealed that the two side chains of omaezallene were essential to its antifouling activity because the activities of nor-bromoallene and nor-bromodiene were significantly diminished. The bromoenyne was found to exhibit potent antifouling activities comparable to omaezallene with low toxicity and ecotoxicity. Preparation of bromoenyne framework is much easier than that of bromodiene moiety in omaezallene. Based on the antifouling activities of the bromoenynes, the synthesis of fluorescent probes and evaluation of their biological activities were also carried out.
  • Fumiaki Nakamura, Hiroshi Maejima, Midori Kawamura, Daisuke Arai, Tatsufumi Okino, Meng Zhao, Tao Ye, Jungyeol Lee, Young-Tae Chang, Nobuhiro Fusetani, Yoichi Nakao
    Bioorganic and Medicinal Chemistry Letters 28 12 2206 - 2209 2018年07月01日 [査読有り][通常論文]
     
    Kakeromamide A (1), a new cyclic pentapeptide encompassing a thiazole ring moiety and a β-amino acid, was isolated from the marine cyanobacterium Moorea bouillonii. Its structure was elucidated by the spectral analysis and the modified Marfey's method. Compound 1 induced differentiation of neural stem cells into astrocytes at the concentration of 10 µM.
  • Michael J. Miller, Tetsuya Miwa, Shun Watanabe, Mari Kuroki, Takatoshi Higuchi, Aya Takeuchi, Kenta Serizawa, Tatsufumi Okino, Katsumi Tsukamoto
    Journal of Marine Biology 2018 2018年 [査読有り][通常論文]
     
    The circumglobal deep-sea gelatinous giant octopod, Haliphron atlanticus, reaches 4 m in length and uses both benthic and pelagic habitats in the upper 3000 m of the ocean during different life history stages, but it is rarely observed due to the deep-depths where it typically lives. It has been collected in trawls and observed a few times near continental margins or islands and has been identified in the stomach contents of deep-diving predators such as sperm whales and blue sharks or detected as body fragments after predation events. An individual H. atlanticus (∼1 m in total length) was video-recorded at 12:21 for about 3 minutes in front of the Shinkai 6500 submersible at 586-599 m (6.5°C, salinity 34.4) along the West Mariana Ridge. It made no escape attempt as the submersible approached and it moved slowly up or down in front of the submersible. It was over the outer seamount-slope (bottom depth ∼3208 m) ∼50 km west of seamounts (≥1529 m summits), but how it fits into the mesopelagic food web along the ridge is unclear. More information is needed to understand the role of H. atlanticus in oceanic food webs and if it typically lives along seamount ridges.
  • Momochika Kumagai, Keisuke Nishikawa, Hiroshi Matsuura, Taiki Umezawa, Fuyuhiko Matsuda, Tatsufumi Okino
    Molecules 23 5 2018年 [査読有り][通常論文]
     
    An investigation of anti-oxidative compounds from the brown alga Dictyopteris undulata has led to the isolation and identification of isozonarol, isozonarone, chromazonarol, zonaroic acid and isozonaroic acid. Their structures were identified by comparison of MS and NMR spectra. Full NMR assignment and absolute configuration of isozonaroic acid are described. Isozonarol showed the most potent 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity among the compounds isolated.
  • Julie G. Petitbois, Loida O. Casalme, Julius Adam V. Lopez, Walied M. Alarif, Ahmed Abdel-Lateff, Sultan S. Al-Lihaibi, Erina Yoshimura, Yasuyuki Nogata, Taiki Umezawa, Fuyuhiko Matsuda, Tatsufumi Okino
    JOURNAL OF NATURAL PRODUCTS 80 10 2708 - 2715 2017年10月 [査読有り][通常論文]
     
    NMR-and MS-guided fractionation of an extract of an Okeania sp. marine cyanobacterium, collected from the Red Sea, led to the isolation of four new metabolites, including serinolamides C (1) and D (2) and lyngbyabellins O (3) and P (4), together with the three known substances lyngbyabellins F (5) and G (6) and dolastatin 16 (7). The planar structures of the new compounds were determined using NMR and MS analyses. The absolute configurations of 1 and 2 were determined by Marfey's analysis of their hydrolysates. The absolute configuration of 3 was ascertained by chiral-phase chromatography of degradation products, while that of 4 was determined by comparison to 3 and 5. The cytotoxic and antifouling activities of these compounds were evaluated using MCF7 breast cancer cells and Amphibalanus amphitrite larvae, respectively. Compounds 3, 4, and 7 exhibited strong antifouling activity, and 3 and 7 were not cytotoxic. A structure-activity relationship was observed for the cytotoxicity of the lyngbyabellins with the presence of a side chain (4 is more active than 3) leading to greater activity. For the antifouling activity, the acyclic form without a side chain (3) was the most active.
  • Yuko Oguri, Mami Watanabe, Takafumi Ishikawa, Takashi Kamada, Charles S. Vairappan, Hiroshi Matsuura, Kensuke Kaneko, Takahiro Ishii, Minoru Suzuki, Erina Yoshimura, Yasuyuki Nogata, Tatsufumi Okino
    MARINE DRUGS 15 9 2017年09月 [査読有り][通常論文]
     
    Six new compounds, omaezol, intricatriol, hachijojimallenes A and B, debromoaplysinal, and 11,12-dihydro-3-hydroxyretinol have been isolated from four collections of Laurencia sp. These structures were determined by MS and NMR analyses. Their antifouling activities were evaluated together with eight previously known compounds isolated from the same samples. In particular, omaezol and hachijojimallene A showed potent activities (EC50 = 0.15-0.23 mu g/mL) against larvae of the barnacle Amphibalanus amphitrite.
  • Julius Adam V. Lopez, Julie G. Petitbois, Charles S. Vairappan, Taiki Umezawa, Fuyuhiko Matsuda, Tatsufumi Okino
    ORGANIC LETTERS 19 16 4231 - 4234 2017年08月 [査読有り][通常論文]
     
    Two new chlorinated fatty acid amides, columbamides D (1) and E (2), along with apratoxins A and C and wewakazole, were isolated from the organic extract of a Moorea bouillonii sample from Sabah, Malaysia. Structure elucidation was accomplished by a combination of MS and NMR analyses. The total synthesis of all four stereoisomers of 1 was completed, and the absolute configuration was determined by chiral-phase HPLC and Marfey's analysis.
  • Shohei Takase, Rumi Kurokawa, Daisuke Arai, Kind Kanemoto Kanto, Tatsufumi Okino, Yoichi Nakao, Tetsuo Kushiro, Minoru Yoshida, Ken Matsumoto
    SCIENTIFIC REPORTS 7 2017年05月 [査読有り][通常論文]
     
    Genome-wide RNA interference (RNAi) with pooled and barcoded short-hairpin RNA (shRNA) libraries provides a powerful tool for identifying cellular components that are relevant to the modes/mechanisms of action (MoA) of bioactive compounds. shRNAs that affect cellular sensitivity to a given compound can be identified by deep sequencing of shRNA-specific barcodes. We used multiplex barcode sequencing technology by adding sample-specific index tags to PCR primers during sequence library preparation, enabling parallel analysis of multiple samples. An shRNA library screen with this system revealed that downregulation of ATP1A1, an a-subunit of Na+/K+ ATPase, conferred significant sensitivity to aurilide B, a natural marine product that induces mitochondria-mediated apoptosis. Combined treatment with ouabain which inhibits Na+/K+ ATPase by targeting a-subunits potentiated sensitivity to aurilide B, suggesting that ATP1A1 regulates mitochondria-mediated apoptosis. Our results indicate that multiplex sequencing facilitates the use of pooled shRNA library screening for the identification of combination drug therapy targets.
  • Loida O. Casalme, Arisa Yamauchi, Akinori Sato, Julie G. Petitbois, Yasuyuki Nogata, Erina Yoshimura, Tatsufumi Okino, Taiki Umezawa, Fuyuhiko Matsuda
    ORGANIC & BIOMOLECULAR CHEMISTRY 15 5 1140 - 1150 2017年02月 [査読有り][通常論文]
     
    The total synthesis of dolastatin 16, a macrocyclic depsipeptide first isolated from the sea hare Dolabella auricularia as a potential antineoplastic metabolite by Pettit et al., was achieved in a convergent manner. Dolastatin 16 was reported by Tan to exhibit strong antifouling activity, and thus shows promise for inhibiting the attachment of marine benthic organisms such as Amphibalanus amphitrite to ships and submerged artificial structures. Therefore, dolastatin 16 is a potential compound for a new, environmentally friendly antifouling material to replace banned tributyltin-based antifouling paints. The synthesis of dolastatin 16 involved the use of prolinol to prevent formation of a diketopiperazine composed of L-proline and N-methyl-D-valine during peptide coupling. This strategy for the elongation of peptide chains allowed the efficient and scalable synthesis of one segment, which was subsequently coupled with a second segment and cyclized to form the macrocyclic framework of dolastatin 16. The synthetic dolastatin 16 exhibited potent antifouling activity similar to that of natural dolastatin 16 toward cypris larvae of Amphibalanus amphitrite.
  • Taiki Umezawa, Keisuke Nishikawa, Tatsufumi Okino, Fuyuhiko Matsuda
    JOURNAL OF SYNTHETIC ORGANIC CHEMISTRY JAPAN 74 7 689 - 699 2016年07月 [査読有り][通常論文]
     
    Biofouling is adverse growth of marine organisms on manmade submersible structures such as ships' hulls and cause significant economic and environmental problems. As a fouling inhibitor, tributyltin (TBT) has been widely used for controlling the sessile organisms since the early 1960s. Unfortunately, serious pollution of the marine environment due to the deleterious effect of TBT prompted the International Maritime Organization (IMO) to call in 2008 for a ban on the use of tributyltin (TBT) on ships. Since marine invertebrates prevent settlement of other benthic marine organisms through the use of natural substances with antifouling properties without causing serious environmental problems, natural antifouling products with good antifouling properties but without biocidal properties have attracted considerable attention. Among these, 10-isocyano-4-cadinene and omaezallene show promise as lead compounds for the development of new environmentally friendly antifouling agents due to its potent antifouling activity against the cypris larvae of the barnacle Amphibalanus amphitrite and low toxicity. 10-Isocyano-4-cadinene, an isocyanosesquiterpene, was isolated from nudibranchs of the family Phyllidiidae. On the other hand, omaezallene is a bromoallene-containing C-15-acetogenin isolated from the red alga Laurencia sp. Herein, we wish to describe our research on the isolations, structure elucidations, total syntheses, and evaluation of the antifouling activities of the natural products and their derivatives. The absolute configurations of the natural products were unambiguously established through our asymmetric total syntheses.
  • Julius Adam V. Lopez, Sultan S. Al-Lihaibi, Walied M. Alarif, Ahmed Abdel-Lateff, Yasuyuki Nogata, Kenji Washio, Masaaki Morikawa, Tatsufumi Okino
    JOURNAL OF NATURAL PRODUCTS 79 4 1213 - 1218 2016年04月 [査読有り][通常論文]
     
    A mass spectrometry (MS)-guided isolation has led to the purification of a new cyanobactin, wewakazole B (1), along with the known compound curacin D from a Red Sea Moorea producens. The planar structure of 1 was elucidated using a combination of NMR and MS techniques. After ozonolysis and acid hydrolysis, the absolute configurations of the amino acid components of 1 were determined by chiral-phase LC-MS and HPLC analyses. Notably, compound 1 exhibited cytotoxic activity toward human MCF7 breast cancer cells (IC50 = 0.58 mu M) and human H460 lung cancer cells (IC50 = 1.0 mu M) and was also found to be inactive in a siderophore assay.
  • Sultan S. Al-Lhaibi, Ahmed Abdel-Lateff, Waled M. Alarif, Yasuyuki Nogata, Seif-Eldin N. Ayyad, Tatsufumi Okino
    Asian Journal of Chemistry 27 6 2252 - 2256 2015年06月01日 [査読有り][通常論文]
     
    Forty two marine macro-organisms include algae, corals and sponges were collected from the Saudi Red Sea territorial water. The methanolic extracts of all the samples were evaluated towards their antifouling effects cyprid larvae of Balanus amphitrite. Fifteen crude extracts showed antifouling activity at 10 μg/mL, eleven of which considered to be promising for isolation targets from the results of low mortality. Two marine species of sponge Siphonochalina siphonella and red alga Laurencia obtusa were selected further chemical investigation. The extract of S. siphonella, was partially fractionated and led to isolation of two known triterpenoidal metabolites sipholenol A (1) and sipholenone A (2). Three compounds 2,10-dibromo-3-chloro-7-chamigrene (3) and 12-hydroxyisolaurene (4) and (12E)-cis-maneonene-E (5), were isolated from L. obtusa. All the compounds (1-5) were evaluated for their antifouling activities. Compounds 1, 3 and 4 showed potent effects with 48 h EC50, 0.2, 0.14 and 1.34 μg/mL, respectively. Compounds 1and 3 were more potent than the positive control CuSO4 (EC50 = 0.34 μg/mL), while compound 2 showed moderate activity at 10 μg/mL.
  • Munehisa Shibata, Kei Onodera, Momochika Kumagai, A. K. M. Azad Shah, Masashi Ogasawara, Hideyuki Kurihara, Tatsufumi Okino, Koretaro Takahashi
    FOOD SCIENCE AND TECHNOLOGY RESEARCH 20 6 1199 - 1205 2014年11月 [査読有り][通常論文]
     
    The potential of supercritical carbon dioxide (SC-CO2) extraction of "koku" enhancing compounds from dried herring fillet ("Migaki-nishin" in Japanese) and sturgeon liver was explored. "Koku" enhancing compounds from a water-soluble extract and a mixed water miscible SC-CO2 extract were isolated and evaluated for their effects on sensory perception. Results showed that only select compounds were found in the mixed water miscible SCCO, extract compared to the complicated composition of the water-soluble extract. A notable feature was that the mixed water miscible SC-CO2 extract contained "koku" enhancing compounds, e.g., nicotinamide, glycerol and creatine. This study revealed for the first time that these compounds were extracted by SC-CO2 extraction and that nicotinamide enhances "koku". We also extracted "koku" enhancing compounds from sturgeon liver using the SCCO, extraction technique. Instrumental analysis revealed that the sturgeon liver contained relatively large amounts of nicotinamide and glycerol. Thus, it is suggested that this technique might be applicable to the extraction of select compounds from fish and fishery by-products.
  • Kensuke Kaneko, Kenji Washio, Taiki Umezawa, Fuyuhiko Matsuda, Masaaki Morikawa, Tatsufumi Okino
    BIOSCIENCE BIOTECHNOLOGY AND BIOCHEMISTRY 78 8 1310 - 1319 2014年08月 [査読有り][通常論文]
     
    The marine red alga genus Laurencia is one of the richest producers of unique brominated compounds in the marine environment. The cDNAs for two Laurencia nipponica vanadium-dependent bromoperoxidases (LnVBPO1 and LnVBPO2) were cloned and expressed in Escherichia coli. Enzyme assays of recombinant LnVBPO1 and LnVBPO2 using monochlorodimedone revealed that they were thermolabile but their K-m values for Br- were significantly lower than other red algal VBPOs. The bromination reaction was also assessed using laurediol, the predicted natural precursor of the brominated ether laurencin. Laurediol, protected by trimethylsilyl at the enyne, was converted to deacetyllaurencin by the LnVBPOs, which was confirmed by tandem mass spectrometry. Native LnVBPO partially purified from algal bodies was active, suggesting that LnVBPO is functional in vivo. These results contributed to our knowledge of the biosynthesis of Laurencia brominated metabolites.
  • Taiki Umezawa, Yuko Oguri, Hiroshi Matsuura, Shohei Yamazaki, Masahiro Suzuki, Erina Yoshimura, Takeshi Furuta, Yasuyuki Nogata, Yukihiko Serisawa, Kazuyo Matsuyama-Serisawa, Tsuyoshi Abe, Fuyuhiko Matsuda, Minoru Suzuki, Tatsufumi Okino
    ANGEWANDTE CHEMIE-INTERNATIONAL EDITION 53 15 3909 - 3912 2014年04月 [査読有り][通常論文]
     
    Natural antifouling products have been the subject of considerable attention. We screened marine algae for antifouling activity and discovered omaezallenes, the new bromoallene-containing natural products isolated from the red alga Laurenciasp. Described is the isolation, structure elucidation, and total syntheses of omaezallenes. The relative and absolute configurations of natural omaezallenes were unambiguously established through total synthesis. The antifouling activities and ecotoxicity of omaezallenes were also evaluated.
  • Sabrin R. M. Ibrahim, Mostafa A. Fouad, Ahmed Abdel-Lateff, Tatsufumi Okino, Gamal A. Mohamed
    NATURAL PRODUCT RESEARCH 28 20 1765 - 1771 2014年 [査読有り][通常論文]
     
    Extensive chromatographic investigation of the ethanolic extract of Alnus japonica Steud stem bark led to the isolation of a new diarylheptanoid named alnuheptanoid A [(5S)-7-(3,4-dihydroxyphenyl)-1-(4-hydroxyphenyl)-5-methoxyheptan-3-one] (8), together with seven known diarylheptanoid derivatives: platyphyllenone (5), (5S)-1,7-bis(4-hydroxyphenyl)-5-methoxyheptan-3-one (6), 1-(3,4-dihydroxyphenyl)-7-(4-hydroxyphenyl)-4-hepten-3-one (7), hirsutenone (9), (5R)-O-methylhirsutanonol (10), hirsutanonol (11) and oregonin (13), three triterpenes: a-amyrin (1), betulinaldehyde (3) and betulinic acid (4), and two sterols: b-sitosterol (2) and daucosterol (12). Compound 6 was isolated for the first time from natural source. The structures of the isolated compounds were determined on the basis of spectroscopic measurements (UV, IR, HR-ESI-MS, 1D and 2D NMR).
  • Lik Tong Tan, Tatsufumi Okino, William H. Gerwick
    MARINE DRUGS 11 8 3015 - 3024 2013年08月 [査読有り][通常論文]
     
    The tropical marine cyanobacterium, Moorea bouillonii, has gained recent attention as a rich source of bioactive natural products. Continued chemical investigation of this cyanobacterium, collected from New Britain, Papua New Guinea, yielded a novel cytotoxic cyclic depsipeptide, bouillonamide (1), along with previously reported molecules, ulongamide A and apratoxin A. Planar structure of bouillonamide was established by extensive 1D and 2D NMR experiments, including multi-edited HSQC, TOCSY, HBMC, and ROESY experiments. In addition to the presence of alpha-amino acid residues, compound 1 contained two unique polyketide-derived moieties, namely a 2-methyl-6-methylamino-hex-5-enoic acid (Mmaha) residue and a unit of 3-methyl-5-hydroxy-heptanoic acid (Mhha). Absolute stereochemistry of the alpha-amino acid units in bouillonamide was determined mainly by Marfey's analysis. Compound 1 exhibited mild toxicity with IC50's of 6.0 mu M against the neuron 2a mouse neuroblastoma cells.
  • Ahmed Abdel-Lateff, Tatsufumi Okino, Walied M. Alarif, Sultan S. Al-Lihaibi
    JOURNAL OF SAUDI CHEMICAL SOCIETY 17 2 161 - 165 2013年04月 [査読有り][通常論文]
     
    A marine fungal isolate, identified as Drechslera sp., was mass cultivated and found to produce a new naturally occurring seco-sativene type sesquiterpene helminthosporic acid (1) and three known sesquiterpenes, helminthosporol (2), drechslerine A (3) and (+) secolongifolene-diol (4). The structures of all compounds were determined by interpretation of their spectroscopic data 1D (H-1 and C-13), 2D (COSY, DQF, NOE, HSQC and HMBC) NMR, MS, UV and IR analyses. All compounds have been tested toward antioxidants, antimicrobial and antifouling effects. (c) 2011 King Saud University. Production and hosting by Elsevier B.V. All rights reserved.
  • Andrea Roxanne J. Anas, Takaya Kisugi, Taiki Umezawa, Fuyuhiko Matsuda, Marc R. Campitelli, Ronald J. Quinn, Tatsufumi Okino
    JOURNAL OF NATURAL PRODUCTS 75 9 1546 - 1552 2012年09月 [査読有り][通常論文]
     
    Bioassay-guided investigation of the cyanobacterium Anabaena compacta extracts afforded spumigin J (1) and the known thrombin inhibitor spumigin A (2). The absolute configuration of 1 was analyzed by advanced Marfey's methodology. Compounds 1 and 2 inhibited thrombin with EC50 values of 4.9 and 2.1 mu M, and 0.7 and 0.2 mu M in the cathepsin B inhibitory assay, respectively. The MM-GBSA methodology predicted spumigin A with 2S-4-methylproline as the better thrombin inhibitor.
  • Kumiko Takahashi, Yongkun Sun, Ikumi Yanagiuchi, Toshiyuki Hosokawa, Takeshi Saito, Miyako Komori, Tatsufumi Okino, Masaaki Kurasaki
    TOXICOLOGY MECHANISMS AND METHODS 22 4 243 - 249 2012年05月 [査読有り][通常論文]
     
    In the laboratory, using a PC12 cell system, studies have been conducted on the effects of various chemicals on apoptosis, as it is considered to be an essential part of normal development, maintenance, and defense in organisms. Stevioside is a natural sweetener extracted from the leaves of Stevia rebaudiana. Since it is widely used as a sugar replacement, it was decided to evaluate the toxicological effects of low concentrations of stevioside on apoptosis induced by serum deprivation using the PC12 cell system. It was found that based on data from DNA electrophoresis and TUNEL signal assays stevioside enhanced apoptosis induced by serum deprivation. This enhancement was caused by increased expression of Bax and of cytochrome c released into the cytosol. These findings suggest that stevioside affects the regulation of the normal apoptotic condition. Further investigation will be needed to clarify the detailed mechanism of the enhancement due to the treatment with stevioside.
  • Taiki Umezawa, Manabu Sueda, Takao Kamura, Teppei Kawahara, Xuerong Han, Tatsufumi Okino, Fuyuhiko Matsuda
    JOURNAL OF ORGANIC CHEMISTRY 77 1 357 - 370 2012年01月 [査読有り][通常論文]
     
    Total syntheses of kalkitoxin, isolated from the Caribbean Lyngbya majuscula, and its analogues, 3-epi-, 7-epi-, 8-epi-, 10-epi-, 10-nor-, and 16-nor-kalldtcocin, were achieved via oxazolidinone-based diastereoselective 1,4-addition reaction of a methyl group and efficient T1C14-mediated thiazoline ring formation as the key steps. The biological activities of synthetic kalkitoxin and its analogues were evaluated with brine shrimp.
  • Teppei Kawahara, Tatsufumi Okino
    Studies in Natural Products Chemistry 36 219 - 247 2012年 [査読有り][通常論文]
     
    Chlorosulfolipids (CSLs) are unusual naturally occurring lipids with complex polychlorinated structures containing mono- or disulfate groups. The first reported CSLs were danicalipin A (2,2,11,13,15,16-hexachlorodocosane-1,14- disulfate) and related precursors from the freshwater microalga Chrysophyceae Ochromonas danica at the end of the 1960s. These planar structures were identified using elemental analysis and MS techniques, after chemical degradation. Although many CSL complexes are cytotoxic and exhibit various biological activities, CSLs from the alga have been ignored by synthetic chemists until recently because of their indeterminate stereochemistry and unclear activity. In the past decade, CSLs were isolated as cytotoxic agents from toxic Adriatic mussels in the course of Diarrheic Shellfish Poisoning research. The absolute configuration of these CSLs was elucidated using J-based configuration analysis (JBCA). The stereochemistry of CSLs in O. danica was determined using both synthetic chemical approaches and analytical chemical approaches. Further, the toxicity of natural isolated CSLs and synthetic CSLs was evaluated. This chapter is a comprehensive review of the isolation, structural determination (focusing on stereochemistry), bioactivity estimation, and roles in vivo of these naturally occurring CSLs, together with the synthetic chemical approaches for CSLs. © 2012 Elsevier B.V. All rights reserved.
  • Keisuke Nishikawa, Hiroshi Nakahara, Yousuke Shirokura, Yasuyuki Nogata, Erina Yoshimura, Taiki Umezawa, Tatsufumi Okino, Fuyuhiko Matsuda
    JOURNAL OF ORGANIC CHEMISTRY 76 16 6558 - 6573 2011年08月 [査読有り][通常論文]
     
    The first enantioselective total synthesis of 10-isocyano-4-cadinene, a marine sesquiterpene isolated from nudibranchs of the family Phyllidiidae, and determination of its absolute stereochemistry were achieved. 10-Isocyano-4-cadinene is expected to be a novel nontoxic antifouling agent. In the synthesis, intermolecular Diels-Alder reaction and samarium diiodide induced Barbier-type cyclization were employed as key steps. The absolute configuration of 10-isocyano-4-cadinene was determined as (1S,6S,7R,10S) by comparison of the optical rotations between natural and synthetic samples. In addition, the authors successfully synthesized 10-epi- and di-1,6-epi-10-isocyano-4-cadinene through the same synthetic pathway. Antifouling activities against Balanus amphitrite with the cadinenes were also evaluated.
  • Peter Bernhardt, Tatsufumi Okino, Jaclyn M. Winter, Akimasa Miyanaga, Bradley S. Moore
    JOURNAL OF THE AMERICAN CHEMICAL SOCIETY 133 12 4268 - 4270 2011年03月 [査読有り][通常論文]
     
    Halogenases catalyze reactions that introduce halogen atoms into electron-rich organic molecules. Vanadium-dependent haloperoxidases are generally considered to be promiscuous halogenating enzymes that have thus far been derived exclusively from eukaryotes, where their cellular function is often disputed. We now report the first biochemical characterization of a bacterial vanadium-dependent chloroperoxidase, NapH1 from Streptomyces sp. CNQ-525, which catalyzes a highly stereoselective chlorination-cyclization reaction in napyradiomycin antibiotic biosynthesis. This finding biochemically links a vanadium chloroperoxidase to microbial natural product biosynthesis.
  • Taiki Umezawa, Masayuki Shibata, Kensuke Kaneko, Tatsufumi Okino, Fuyuhiko Matsuda
    ORGANIC LETTERS 13 5 904 - 907 2011年03月 [査読有り][通常論文]
     
    Asymmetric total synthesis of danicalipin A was achieved. The synthesis was characterized by diastereoselective introduction of chlorine atoms. Biological activities with synthetic danicalipin A, its enantiomer, and racemate were also evaluated toward brine shrimp. Both enantiomers of danicalipin A showed almost the same activity.
  • Keisuke Nishikawa, Hiroshi Nakahara, Yousuke Shirokura, Yasuyuki Nogata, Erina Yoshimura, Taiki Umezawa, Tatsufumi Okino, Fuyuhiko Matsuda
    ORGANIC LETTERS 12 5 904 - 907 2010年03月 [査読有り][通常論文]
     
    The first enantioselective total synthesis of 10-isocyano-4-cadinene, a marine sesquiterpene isolated from nudibranchs of the family Phyllidiidae, was achieved. The cadinene is expected to be a novel nontoxic antifouling agent. In the synthesis, an intermolecular Diels-Alder reaction and a SMl(2)-induced Barbier-type reaction were employed as key steps. The absolute configuration of 10-isocyano-4-cadinene was determined to be (1S, 6S, 7R, 10S) on the basis of the total synthesis. Antifouling activities against Balanus amphitrite with both enantiomers of 10-isocyano-4-cadinene were also evaluated.
  • Andrea Roxanne J. Anas, Irene M. Villasenor, Hiroshi Matsuura, Tatsufumi Okino
    PHILIPPINE AGRICULTURAL SCIENTIST 92 4 388 - 391 2009年12月 [査読有り][通常論文]
     
    The bark of Ziziphus talanai (Blanco) Merrill, a tree endemic to the Philippines, is traditionally used in Antique to cure kidney problems such as urinary tract infections (UTI), and skin diseases such as scabies and ringworm. Its antimicrobial activity was screened against several microorganisms to have a more comprehensive anti-infective profile of the plant. The MeOH extract of Z. talanai bark exhibited antimicrobial activity against Gram-positive Mycobacterium phlei, S. aureus and B. subtilis at 20,000 mu g and 2,000 mu g but was inactive against Gram-negative E. coli, P aeruginosa, C. albicans and S. cerevisiae. It has minimal antifungal activity against T mentagrophytes. The MeOH extract of Z. talanai is therefore inactive against uncomplicated UTI, which is mostly caused by E. coli. Further bioassay-guided isolation and subsequent spectral analysis yielded ceanothic acid, whose activity is specific to M. phlei at 100 mu g. M. phlei causes chronic ambulatory peritoneal dialysis-associated peritonitis.
  • Amira M. Gamal-Eldeen, Ahmed Abdel-Lateff, Tatsufumi Okino
    ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 28 3 317 - 322 2009年11月 [査読有り][通常論文]
     
    A marine fungal isolate, Penicillium sp. fungus isolated from seaweed, Ova sp., led to the isolation of a new chromone derivatives, 2-(hydroxymethyl)-8-methoxy-3-methyl-4H-chromen-4-one (chromanone A). The structure was determined by interpretation of their spectroscopic data (1D and 2D NMR, MS, UV and IR). At the nitiation stage of carcinogenesis, carcinogens is activated by cytochrome P-450 1A (CYP1A) and detoxified by glutathione S-transferases (GST), quinine reductase (QR), and epoxide hydrolase (mEH). We tested the modulatory effect of chromanone A on these carcinogen metabolizing enzymes. The results indicated that chromanone A (4 mu g/ml) is a promising inhibitor of CYP1A activity up to 60% of the stimulated-CYP1A in murine hepatoma cells (Hepa1c1c7), and it significantly induced GST but not total thiols at low concentrations. Chromanone A had no influence on QR activity, while it resulted in a significant dose-dependant enhancement mEH activity in Hepa1c1c7 cells (P<0.05-0.01). Additionally, chromanone A possessed a potent specific radical scavenging activity against hydroxyl radicals more than peroxyl radicals that may be responsible for the inhibitory effect of chromanone A on the induced-DNA damage in cells. In conclusion, this study proved that chromanone A may act as an active tumor anti-initiating via modulation of carcinogen metabolizing enzymes and protection from DNA damage. (C) 2009 Elsevier B.V. All rights reserved.
  • 梅澤 大樹, 香村 隆夫, 河原 哲平, 末田 学, 韓 雪容, 沖野 龍文, 松田 冬彦
    天然有機化合物討論会講演要旨集 51 329 - 334 天然有機化合物討論会 2009年09月01日 
    Kalkitoxin (1) was isolated from cyanobacterium Lyngbya majuscule in the Caribbean Sea. It is reported that 1 posssesses some intersting biological activities. For example, 1 shows a strong ichtyotoxic activity toward the common gold fish and brine shrimp. Also, kalkitoxin has a strong neurotoxicity (LC_<50>=3.86nM) in cerebellar granule neouron (CGN) as an inhibitor N-methyl-D-aspartate (NMDA) receptor antagonists and is a highly potent blocker of the voltage-depending sodium channel in mouse neuro-2a cells (EC_<50>=1nM). We have been attracted by the structure-activity relationship of kalkitoxins. In present paper, we describe the synthesis of kalkitoxin and its analogues (epimer and demethylated kalkitoxins (nor form) and their biological activity with brine shrimp. The synthesis was started from 15, which was converted to α,β-unsaturaed imide 14 with phosphonate 17. 1,4-Addition reaction to 14 with methyl curprate gave imide 18 as 10 : 1 mixture of diastereomers. The imide 18 was transformed into second 1,4-addition precursor 11 in 9 steps. The conjugate addition reaction of 11 proceeded smoothly to give imide 26 as a single diastereomer, which was derived to 1 via condensation with amine 10, synthesize without racemization by novel method, and highly efficient thiazoline formation with TiCl_4. Kalkitoxin analogues 2-7 were synthesized in the similar manner by simply changing the chiral auxiliary or chiral building block. Finally, the biological activity with 1-7 was evaluated as LC_<50> toward brine shrimp.
  • Teppei Kawahara, Yasuhiro Kumaki, Takashi Kamada, Takahiro Ishii, Tatsufumi Okino
    JOURNAL OF ORGANIC CHEMISTRY 74 16 6016 - 6024 2009年08月 [査読有り][通常論文]
     
    We isolated eight chlorosulfolipids (1-8) from the chrysophyta Ochromonas danica (IAM CS-2), including five nest chlorosulfolipids (2-5, 8). The planar structures of all the compounds were elucidated by 1D and 2D NMR and ESI-MS/MS analyses. We determined the relative configuration of seven chlorosulfolipids (1-7), including the most commonly known chlorosulfolipid, 2,2,11,13,15,16-hexachlorodocosane-1,14-disulfate (1), by J-based configuration analysis (JBCA). The absolute configuration of each compound was determined using a modified Mosher's method after chemical degradation. 2,2,11,13,15,16-Hexachloro-14-docosanol-1-sulfate (2) was the most toxic to brine shrimp (Anemia saliva) larvae (LC50 0.27 mu g/mL). Compounds 1 and 4-8 were less toxic (LC50, 2.2-6.9 mu g/mL). Compound 3 was not toxic at 30 mu g/mL.
  • Hiroshi Matsuura, Ikuko Yazaki, Tatsufumi Okino
    FISHERIES SCIENCE 75 3 777 - 783 2009年05月 [査読有り][通常論文]
     
    Larval metamorphosis inducers of the sea cucumber Apostichopus japonicus were screened from physiologically active compounds. Doliolaria larvae completed their metamorphosis to juveniles in 120 h when treated with 5-10 mu M of dopamine and l-DOPA, and 50 mu M of l-adrenaline and l-noradrenaline. Doliolaria larvae had to be exposed to dopamine or l-DOPA for at least 24 h. D1-like dopamine receptor antagonists SKF87566 and LE300 (10 mu M) inhibited metamorphosis by dopamine. However, the D2-like dopamine receptor antagonists sulpiride and nemonapride (10 mu M) did not inhibit the effect of dopamine. The results suggest that D1-like dopamine receptors are involved in larval metamorphosis of the sea cucumber A. japonicus.
  • Takaya Kisugi, Tatsufumi Okino
    JOURNAL OF NATURAL PRODUCTS 72 4 777 - 781 2009年04月 [査読有り][通常論文]
     
    Micropeptins C (1), D (2), E (3), and F (4) have been isolated from the freshwater cyanobacterium Microcystis aeruginosa (NIES-100). The structures were elucidated by analyses of MS, NMR spectra, and chemical degradation. Micropeptins C, D, E, and F inhibited chymotrypsin with IC(50)'s of 1.1, 1.2, 1.0, and 1.5 mu g/mL, respectively.
  • Ahmed Abdel-Lateff, Ehab S. Elkhayat, Mostafa A. Fouad, Tatsufumi Okino
    NATURAL PRODUCT COMMUNICATIONS 4 3 389 - 394 2009年03月 [査読有り][通常論文]
     
    Two antifouling compounds, aureobasidin (1), a new ester with an unusual 4,6-dihydroxydecanoic acid residue, and (3R,5S)-3,5-dihydroxydecanoic acid (2), were isolated from the marine-derived fungus Aureobasidium sp., in addition to (5R,3Z)-5-hydroxydec-3-enoic acid (3) and (R)-3-hydroxydecanoic acid (4). The structures were unambiguously established by IR, 1D and 2D NMR spectroscopic and mass spectral data. Compounds 1-3 were found to be active against Bacillus subtilis, Escherichia coli and Staphyllococcus aureus. Compound 3 showed fungistatic activity against Candida albicans.
  • Antifouling alkaloids from Crinum augustum (Amaryllidaceae)
    Pharmacog. Res. 1 43 - 52 2009年 [査読無し][通常論文]
  • Gamal A. Mohamed, Ahmed Abdel Lateff, Mostafa A. Fouad, Sabrin R. M. Ibrahim, Ehab S. Elkhayat, Tatsufumi Okino
    PHARMACOGNOSY MAGAZINE 5 17 28 - 36 2009年01月 [査読無し][通常論文]
     
    Phytochemical study of the aerial parts of Imperata cylindrica Beauv. (Graminae), growing in Egypt afforded four methoxylated flavonoids 1-4, beta-sitosterol-3-O-beta-D-glucopyranosyl-6' -tetradecanoate 5, 3-hydroxy-4-methoxy-benzaldehyde 6, together with daucosterol, beta-sitosterol and alpha-amyrin 7-9. To the best of our knowledge, this is the first isolation of compounds 1-5 from the genus Imperata. A significant hepato-protective activity had been observed upon co-administration of the methanolic extracts of I. cylindrica with CCl(4). The structures were determined using spectroscopic data; 1D ((1)H and (13)C), 2D (HSQC, and HMBC) NMR; MS; UV and IR.
  • Gamal A. Mohamed, Ahmed Abdel Lateff, Mostafa A. Fouad, Sabrin R. M. Ibrahim, Ehab S. Elkhayat, Tatsufumi Okino
    PHARMACOGNOSY MAGAZINE 5 17 28 - 36 2009年01月 [査読有り][通常論文]
     
    Phytochemical study of the aerial parts of Imperata cylindrica Beauv. (Graminae), growing in Egypt afforded four methoxylated flavonoids 1-4, beta-sitosterol-3-O-beta-D-glucopyranosyl-6' -tetradecanoate 5, 3-hydroxy-4-methoxy-benzaldehyde 6, together with daucosterol, beta-sitosterol and alpha-amyrin 7-9. To the best of our knowledge, this is the first isolation of compounds 1-5 from the genus Imperata. A significant hepato-protective activity had been observed upon co-administration of the methanolic extracts of I. cylindrica with CCl(4). The structures were determined using spectroscopic data; 1D ((1)H and (13)C), 2D (HSQC, and HMBC) NMR; MS; UV and IR.
  • Charles Santhanaraju Vairappan, Minoru Suzuki, Takahiro Ishii, Tatsufumi Okino, Tsuyoshi Abe, Michio Masuda
    PHYTOCHEMISTRY 69 13 2490 - 2494 2008年10月 [査読有り][通常論文]
     
    During our studies on Malaysian Laurencia species, brominated metabolites, tiomanene, acetylmajapolene B, and acetylmajapolene A were isolated from an unrecorded species collected at Pulau Tioman, Pahang along with known majapolene B and majapolene A. Acetylmajapolene A was a mixture of diastereomers as in the case of majapolene A. Tiomanene may be a plausible precursor for acetylmajapolenes B and A. In addition, three known halogenated sesquiterpenes and two known halogenated C(15) acetogenins were found from other two unrecorded species collected at Pulau Karah, Terengganu and Pulau Nyireh, Terengganu, respectively. Some of these halogenated metabolites showed moderate antibacterial activity against some marine bacteria. (c) 2008 Elsevier Ltd. All rights reserved.
  • 河原 哲平, 沖野 龍文
    天然有機化合物討論会講演要旨集 50 391 - 396 天然有機化合物討論会 2008年09月01日 
    Chlorosulfolipids (CSLs) are unusual naturally occurring compounds, which were first isolated at the end of the 1960s from freshwater microalgae such as Chrysophyceae Ochromonas danica and Poterioochromonas malhamensis. They constitute 15% of total lipids. The preparation of the CSLs in sufficient purity for structural characterization has proven to be difficult because the polar lipids were extremely hydroscopic and viscously. Therefore, any bioassays have not taken in nature form and structural elucidation was not satisfied with stereochemical analysis. Herein, we report successful isolation and determination of relative and absolute configuration of eight chlorosulfolipids. The Chrysophyta O. danica (IAM CS-2) was cultured at 25℃ for 1 week in a medium containing 0.1% glucose, 0.1% tryptone, 0.1% yeast extract and 0.05% meat extract with aeration. The cells were collected by continuous centrifugation, and freeze dried. The freeze-dried cells were homogenized and extracted with 1L of MeOH (three times) and 1L of EtOAc. The combined extracts were evaporated in vacuo and sequentially extracted with hexane, CHCl_3, EtOAc, BuOH and water. The active fractions (EtOAc, BuOH) of brineshrimp assay were applied repeatedly to silica gel and flash ODS column chromatography. Finally reverse phase-HPLC using a C_<30> column and an ELSD detector yielded four known CSLs (1,6-8) and four new compounds (2-5). Compound 1 was a major component of CSL from O. danica. Planar structure of 1 was established by HR-ESI-MS, 1D, 2D NMR and ESI-MS/MS. By using the JBCA method, relative configurations of 1 were determined by measuring ^<23>_J_ from HETLOC and J-IMPEACH-MBC spectrum. The absolute configuration was determined by modified Mosher's method after the sulfatide was hydrolyzed. In conclusion, 1 was identified as 2,2,11,13,15,16-hexachlorodocosane 1,14-disulfate. In the same manner, structures of 2-8 (2: 2,2,11,13,15,16-hexachloro-14-docosanol 1-sulfate, 3: 2,2,11,13,15,16-hexachlorodocosane 1,14-diol, 4: 11,13,15,16-tetrachlorodocosane 1,14-disulfate, 5: 11,13,15-tri-chlorodocosane 1,14-disulfate, 6: 13-chlorodocosane 1,14-disulfate, 7: docosane 1,14-disulfate, 8: 14-chlorotetracosane 1,15-disulfate) were determined.
  • Masanobu Yamamoto, Tatsufumi Okino, Saiko Sugisaki, Tatsuhiko Sakamoto
    ORGANIC GEOCHEMISTRY 39 6 754 - 763 2008年 [査読有り][通常論文]
     
    Biomarkers in Late Pleistocene sediments collected from the Integrated Ocean Drilling Program (IODP)-Arctic Coring Expedition (ACEX) Hole M0004C (central Arctic Ocean) were investigated. The major biomarkers are long chain n-alkanes, n-fatty acids and n-alkan-1-ols, indicating fresh organic matter (OM) derived predominantly from higher plants. The dominance of terrestrial biomarkers is attributed to severe OM degradation caused by slow sedimentation in oxygen-rich benthic water and/or low primary production due to permanent sea ice coverage. Hopanes, representing thermally altered OM, tend to be abundant in samples with abundant ice rafted debris (IRD). An OM-rich dark grey layer deposited during marine isotope stage (MI5) 6 contains a significant amount of branched glycerol dialkyl glycerol tetraethers (branched GDGTs), suggesting ice erosion of organic-rich continental soil followed by transportation to the central Arctic by drifting ice. The labile-refractory index (i.e., the abundance ratio of long chain n-alkan-1-ols to the sum of long chain n-alkanes and long chain n-alkan-1-ols) decreases above the dark grey layer, indicating that the OM became more refractory. This change suggests that coverage of the source region by OM-rich soil decreased because of extensive glacial erosion during MIS-6. (C) 2008 Elsevier Ltd. All rights reserved.
  • Takahiro Ishii, Tatsufumi Okino, Yosuke Mino, Hiroaki Tamiya, Fuyuhiko Matsuda
    PLANT GROWTH REGULATION 52 2 131 - 139 2007年06月 [査読有り][通常論文]
     
    Starfish waste has been shown to be an effective compost material not only in the promotion of plant growth but also in terms of having insecticidal activity. In the present study, plant growth regulation by chemicals from starfish was examined. The aqueous fraction from a hot water extract of the starfish Asterias amurensis Lutken showed plant-growth activity, while the aqueous fraction from a methanol extract inhibited growth of Brassica campestris. The lipophilic fraction from the methanol extract also exhibited a plant growth-promoting effect. The active components from each extract were identified. Asterubine from the hot water extract promoted plant growth. A ceramide from the lipophilic fraction showed root growth promoting effect, and three glucocerebrosides had promotive effects on the entire plant. Asterosaponins were identified as the main growth inhibitors in the aqueous fraction of the methanol extract. These active compounds from starfish waste could be analyzed as potential plant growth regulators in agricultural applications in the future.
  • 石井 貴広, 沖野 龍文, 美濃 羊輔, 田宮 寛明, 松田 冬彦
    天然有機化合物討論会講演要旨集 48 295 - 300 天然有機化合物討論会 2006年09月15日 
    A large number of studies on the isolation and structure elucidation of sphingolipids from starfish have been reported. These compounds are the predominant metabolites of starfish and include a broad variety of pharmacological activities. In recent years, outbreak of starfish in Hokkaido causes serious damage to the fishery and aquacultural grounds for benthic shellfish. Although such starfish is a nuisance to fishermen, the collected starfish can be used as fertilizer. In our preliminary growth test, starfish compost mix showed plant-growth promoting effect to the plant Brassica campestris (Komatsuna). Thus, we investigated Asterias amurensis Lutken as a source of plant-growth promoters. A bioassay-guided separation of both hot water and methanol extracts from A. amurensis gave several active fractions which showed plant-growth promoting effect. A new glucocerebroside, asteriacerebroside G (1) and a new ceramide, asteriaceramide A (2), together with two known compounds, asteriacerebrosides A and B were isolated from the lipophilic fractions from the methanol extract. Three asteriacerebrosides had promotive effect on the entire plant body of B. campestris. On the other hand, asteriaceramide A (2) exhibited a root growth promoting effect. Moreover, the aqueous fraction from the water extract contained a sulfur-containing guanidine derivative, asterubine. In order to study the effect of active asterubine, we produced synthetic asterubine. The promotive activity of natural asterubine was equivalent to that of the synthesized product. These active compounds from unutilized natural resource A. amurensis could be employed as useful plant-growth regulators in a number of agricultural technologies in the future.
  • ISHII Takahiro, OKINO Tatsufumi, MINO Yosuke
    J. Nat. Prod 69 7 1080 - 1082 2006年07月 [査読有り][通常論文]
     
    The new phytosphingosine-type ceramide asteriaceramide A (1) and glucocerebroside asteriacerebroside G (2), together with two known cerebrosides, asteriacerebrosides A and B, were isolated from lipophilic fractions of the whole bodies of the Northern Pacific starfish Asterias amurensis Lutken. The water-soluble fraction afforded two known asterosaponins, glycoside B-2 and asterosaponin-1. The structures of 1 and 2 were determined on the basis of chemical and spectroscopic evidence as (2S,3S,4R,13Z)-2-[(2'R)-2-hydroxyhexadecanoylamino]-13-docosene-1,3,4-triol (1) and 1-O-(beta-D-glucopyranosyl)-( 2S,3R,4E,13Z)-2-[(2'R)-2-hydroxytetradecanoylamino]-4,13-docosadiene-1,3-diol (2). Compounds 1, 2, and asteriacerebrosides A and B promoted plant growth in sprouts of Brassica campestris.
  • T Ishii, T Okino, M Suzuki, Y Machiguchi
    JOURNAL OF NATURAL PRODUCTS 67 10 1764 - 1766 2004年10月 [査読無し][通常論文]
     
    Two novel phenylpropanoic acid derivatives, tichocarpol A (1) and tichocarpol B (2), were isolated along with floridoside and isethionic acid from the red alga Tichocarpus crinitus. The structures of these novel metabolites were elucidated using a combination of spectral (1D and 2D NMR techniques and ESIMS) and chemical methods. Compounds 1, 2, and floridoside exhibited feeding-deterrent activity against the sea urchin Strongylocentrotus intermedius.
  • Y Fukuta, T Ohshima, Gnanadesikan, V, T Shibuguchi, T Nemoto, T Kisugi, T Okino, M Shibasaki
    PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 101 15 5433 - 5438 2004年04月 [査読無し][通常論文]
     
    Fukuta, Y., T. Ohshima, V. Gnanadesikan, T. Shibuguchi, T. Nemoto, T. Kisugi, T. Okino, & M. Shibasaki, Enantioselective syntheses and biological studies of aeruginosin 298-A and its analogs: Application of catalytic asymmetric phase-transfer reaction. Proc. Nat. Acad. Sci. USA, 101(15), 5433-5438.*
  • Li, W. I., Marquez, B. L. ., Okino, T., Yokokawa, F., Shioiri, T., Gerwick, W. H. & Murray, T. F., Characterization of the preferred stereochemistry for the neuropharmacologic actions of antillatoxin. J. Nat. Prod., 67 (4), 559-568.*
    2004年 [査読無し][通常論文]
  • Yokokawa, F., Asano, T., Okino, T., Gerwick, W. H., & Shioiri, T., An expeditious total synthesis of kalkitoxins: determination of the absolute stereoctructure of natural kalkitoxin. Tetrahedron, 60 (32), 6859-6880.*
    2004年 [査読無し][通常論文]
  • Ishii, T., Okino, T., Suzuki, M., Kuramata, K. & Machiguchi, Y., Feeding-deterrent activity of phenylpropanoids from the red alga Tichocarpus crinitus against the sea urchin Strongylocentrotus intermedius, Mar. Biotechnol., 6, S247-S251.*
    2004年 [査読無し][通常論文]
  • Tatsufumi Okino, Erina Yoshimura, Hiroshi Hirota, Nobuhiro Fusetani
    Journal of Natural Products 59 11 1081 - 1083 1996年11月 [査読有り][通常論文]
     
    Two new diterpene formamides were isolated from the marine sponge Acanthella cavernosa collected off Yakushima Island, along with seven known diterpenes. Their structures proved to be kalihipyran derivatives on the basis of spectral data. All nine compounds showed potent antifouling activity against larvae of the barnacle Balanus amphitrite.
  • 廣田 洋, 塚本 佐知子, 沖野 龍文, 伴野 安彦, 加藤 治子, 吉村 えり奈, 伏谷 伸宏
    天然有機化合物討論会講演要旨集 38 451 - 456 天然有機化合物討論会 1996年09月02日 
    As a part of our study on larval settlement (attachment and metamorphosis) of sessile marine invertebrates, we are searching the settlement inducing and inhibiting substances from various marine organisms. Here we present our new findings on the metamorphosis inducing compounds on ascidian Halocynthia roretzi larvae and the antifoulants against barnacle Balanus amphitrite larvae. Metamorphisis of ascidian larvae has been thought to be induced by some chemical cues. a) We found the conditioned medium with the ascidian H. roretzi larvae induced the larval metamorphosis of the conspecies. The metamorphosis-inducer has been isolated, and the strucutre was identified as lumichrome (1). b) From various marine organisms, we have isolated almost 40 compounds including 24 new ones as the metamorphosis-inducers on the ascidian. For example, from a marine sponge Callyspongia sp. (to be), ten acyclic polyacetylene derivatives were obtained (e.g. 2 and 3). A marine sponge Stelletta sp. afforded a norsesequiterpenamide with two guanidium moieties, stellettadine A (4), the absolute stereochemistry of which was determined by degradation into 2-methylglutaric acid. From the marine sponge Anthosigmella aff. raromicrosclera, two pipecolate derivatives (5 and 6) were obtained. On MeOH extracts of more than 300 marine invertebrates, we have performed antifouling screening against barnacle larvae (B. amphitrite). Following the screening result, we attempted the isolation and structure determination of antifoulants to afford more than 60 compounds including almost 30 new ones. a) From the marine sponge Acanthella cavernosa, 26 antifoulants were obtained. Kalihinane-type compounds with isocyano, formamino, and/or isothiocyano group(s) showed prominent antifouling activities, some of which were stronger than that of cupric sulfate. Steroids with epidioxy group (e.g. 7) delayed the timing of larval settlement. b) Nudibranchs of the family Phillidiidae afforded 11 sesquiterpenoid antifoulants (e.g. 8). c) From the marine sponge Pseudoceratina purpurea, seven antifoulants (9 - 15) including a unique cyanoformamide derivative (14) were obtained. d) The marine sponge Agelas mauritiana afforded oroidin and its unique dimer (16). e) From a marine sponge Axinyssa sp., three new sesquiterpenoids with dichloromethyleneamino group (17-19) were obtained. f) A soft coral Dendronephthya sp. afforded four new D-seco-steroids (e.g. 20). These research results will become important on understanding the more concise mechanism of larval settlement and for development of commercial antifouling agents.
  • 沖野 龍文, 廣田 洋, 伴野 安彦, 吉村 えり奈, 伏谷 伸宏
    天然有機化合物討論会講演要旨集 37 337 - 342 天然有機化合物討論会 1995年09月01日 
    It is widely believed that sessile marine organisms possess chemical defenses against fouling organisms. Therefore, these secondary metabolites might be potential non-toxic antifouling agents. During our search for antifouling agents from Japanese marine organisms, we found that extracts of nudibranchs of the genus Phyllidia and of sponges of the genus Acanthella inhibited larval settlement and metamorphosis of Balanus amphitrite. Bioassay-guided isolation afforded sixteen new along with sixteen known terpenoids. Extracts of sponges and nudibranchs were subjected to solvent partitioning, silica-gel column chromatographies and HPLC. Five new kalihinenes and kalihipyrans have been isolated from a sponge Acanthella collected off Yakushima island, while 4 new kalihinols, a new diterpene hydrocarbon, and two new sesquiterpenes have been obtained from a sponge Acanthella collected off Hachijo-jima island. Four new sesquiterpenes have been obtained from 3 nudibranchs of the genus Phyllidia collected in the southern Kyushu. Molecular formulas of kalihinane diterpenes were established by high resolution MS. IR spectra suggested their functionalities; isonitrile, isothiocyanate, or isocyanate. Extensive 2D NMR analyses were applied to elucidate their structures. Especially, stereochemistries were determined by NOESY experiments and values of coupling constants. Compounds 1-3 were the first examples of kalihinene-type diterpenes in tetrahydropyran series, while 12 was a rare compound possessing an isocyanate functionality as a natural product. Structures of six new sesquiterpenes were elucidated mainly by 2D NMR analyses. A compound 32 had a new carbon skeleton. Most of these compounds showed strong antifouling activity against the barnacle Balanus amphitrite larvae. Especially, 15-formamidokalihinene (6), 10-formamidokalihinene (7), kalihinol A (8), 3-isocyanotheonellin (28), and 10-isocyano-4-cadinene (30) showed potent antifouling activity, more active than CuSO_4.
  • 沖野 龍文, 松田 久, 原口 亮, 村上 昌弘, 山口 勝己
    天然有機化合物討論会講演要旨集 34 486 - 493 天然有機化合物討論会 1992年09月10日 
    Microalgae are rich sources of structurally-novel and biologically-active compounds. In the course of our screening program of enzyme inhibitors from microalgae, we found potent trypsin-inhibitory activity in the extract of cultured freshwater blue-green alga Microcystis aeruginosa. Microcystis aeruginosa (NIES-100) was obtained from the National Institute for Environmental Studies, Japan. The 80% methanol extract of lyophilized alga (248g) harvested from 810L culture was subjected to solvent partition, DEAE, SiO_2 and ODS column chromatography, finally to reversed-phase HPLC using ODS column to obtain trypsin inhibitors named micropeptin A (1) and micropeptin B (2). Molecular formula of micropeptin A was decided as C_<49>H_<78>N_8O_<13> from HRFABMS and NMR data. Amino acid analysis of the acid hydrolyzate gave Thr, Glu, Val, Leu, Lys and N-MeTyr. ^1H-^1H COSY, HOHAHA, HMQC-HOHAHA and HMBC spectra showed the presence of these six amino acids, octanoic acid and 3-amino-6-hydroxy-2-piperidone. Interpretation of HMBC and ROESY spectra revealed the cyclic structure of 1. The structure of 2 only differs from 1 in having hexanoic acid in place of octanoic acid. Chiral GC and LC analyses indicated all the usual amino acids to be in L-form. The IC_<50> of 1 against trypsin and plasmin was 0.071; 0.026μg/mL, respectively.

その他活動・業績

特許

共同研究・競争的資金等の研究課題

  • 海藻の含ハロゲン化合物の生合成
    研究期間 : 2008年
  • 天然物由来船底防汚剤の開発
    研究期間 : 2001年
  • Natural antifouling compounds
    研究期間 : 2001年
  • 海洋生物の生物間相互作用に関する物質
  • Bioactive substancec in marine life

教育活動情報

主要な担当授業

  • 大学院共通授業科目(教育プログラム):PARE
    開講年度 : 2021年
    課程区分 : 修士課程
    開講学部 : 大学院共通科目
    キーワード : 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
  • 生体物質科学特論Ⅱ
    開講年度 : 2021年
    課程区分 : 修士課程
    開講学部 : 環境科学院
    キーワード : 天然物化学、化学生態学 Natural Product Chemistry, Chemical Ecology
  • 国際環境保全学総論
    開講年度 : 2021年
    課程区分 : 修士課程
    開講学部 : 環境科学院
    キーワード : SDGs, disaster, resources, energy, inequality, ODA, pollution, sustainablitiy, climate change, community
  • 環境科学研究基礎論
    開講年度 : 2021年
    課程区分 : 修士課程
    開講学部 : 環境科学院
    キーワード : 研究倫理 統計 プレゼンテーション アカデミックスキル Research ethics, statistics, presentation, academic skills
  • 大学院共通授業科目(教育プログラム):JICA開発大学院連携プログラム環境科学
    開講年度 : 2021年
    課程区分 : 修士課程
    開講学部 : 大学院共通科目
    キーワード : SDGs, disaster, resources, energy, inequality, ODA, pollution, sustainablitiy, climate change, community
  • 統合環境分析法実習
    開講年度 : 2021年
    課程区分 : 修士課程
    開講学部 : 環境科学院
    キーワード : 環境汚染物質、環境分析、影響評価  Environmental Contaminants, Environmental Analyses, Biological Assessment for Environmental Contaminants
  • 環境起学基礎演習
    開講年度 : 2021年
    課程区分 : 修士課程
    開講学部 : 環境科学院
    キーワード : 研究倫理 統計 プレゼンテーション アカデミックスキル Research ethics, statistics, presentation, academic skills
  • 環境計量学特論
    開講年度 : 2021年
    課程区分 : 修士課程
    開講学部 : 環境科学院
    キーワード : 環境計測、水質汚濁、大気汚染、計量法、環境法、統計学、環境分析法、放射線計測、計量管理 environmental measurement, water pollution, air pollution, dosimetry, metrology, environment law, statistics, environmental analytical methods, measuring control
  • 環境適応学総論
    開講年度 : 2021年
    課程区分 : 修士課程
    開講学部 : 環境科学院
    キーワード : 環境適応学、環境と物質、重金属、化学物質のリスクアセスメント、ナノテクノロジーの基礎 Environmental adaptation science, Environment and materials, Heavy metals, Risk assessment of chemicals, Nano-technology for environmental adaptation
  • 環境適応学特論
    開講年度 : 2021年
    課程区分 : 修士課程
    開講学部 : 環境科学院
    キーワード : environmental remediation, porous materials, risk assessment, management for chemicals, monitored natural attenuation, and statistical analysis (t-test, χ2-test, and F-test)
  • 大学院共通授業科目(教育プログラム):JICA開発大学院連携プログラム環境科学
    開講年度 : 2021年
    課程区分 : 修士課程
    開講学部 : 大学院共通科目
    キーワード : 気候変動とその対策、持続可能な開発目標、生態系、生物多様性、生態系を利用した災害緩和、生態系撹乱、環境修復、湿地・湿原、里山、植生、オゾン枯渇、化学センサー、環境計測 global warming and its countermeasure, sustainable development goals, ecosystems, biodiversity, disaster reduction using ecosystem, ecological disturbance, remediation, wetland, satoyama, vegetation, ozone depletion, chemical sensor, environmental monitoring
  • 大学院共通授業科目(教育プログラム):社会と健康
    開講年度 : 2021年
    課程区分 : 修士課程
    開講学部 : 大学院共通科目
    キーワード : SDGs, Environmental Health
  • 化学Ⅱ
    開講年度 : 2021年
    課程区分 : 学士課程
    開講学部 : 全学教育
    キーワード : 有機化合物、官能基、分子構造、化学的性質、化学反応、炭素の混成軌道、炭化水素、芳香族化合物、アルコール、カルボニル化合物


Copyright © MEDIA FUSION Co.,Ltd. All rights reserved.