This page has only limited features, please log in for full access.

Unclaimed
Hiroshi Nagai
Department of Ocean Sciences, Tokyo University of Marine Science and Technology, Konan-4, Minato-ku, Tokyo 108-8477, Japan

Basic Info

Basic Info is private.

Honors and Awards

The user has no records in this section


Career Timeline

The user has no records in this section.


Short Biography

The user biography is not available.
Following
Followers
Co Authors
The list of users this user is following is empty.
Following: 0 users

Feed

Journal article
Published: 31 August 2021 in Foods
Reads 0
Downloads 0

Hidakakombu (Saccharina angustata), commonly known as kelp, is an edible macroalgae mainly grown in the Hidaka region of Hokkaido. Hidakakombu is graded based on its shape and color. Low-grade Hidakakombu has low value and is distributed at a low price. It is desired to establish a method to add value to low-grade Hidakakombu. In this study, low-grade Hidakakombu was fermented by Lacticaseibacilluscasei 001 to add value. Fermentation of Hidakaombu enhanced the inhibition of blood pressure elevation due to ACE inhibition. L. casei 001 in fermented Hidakakombu remained viable in simulated gastric and intestinal juices. The ACE inhibitory component in L. casei001-fermented Hidakakombu was isolated from the fraction below 3 kDa using high-performance liquid chromatography. The purified amino acid was identified as D-Trp using nuclear magnetic resonance, mass spectroscopy, and optical rotation measurements. This is the first report on the ACE inhibitory activity of D-Trp in L. casei 001-fermented Hidakakombu. Hidakakombu fermented by L. casei001 was shown to be a source of probiotics and functional components against hypertension. Therefore, fermentation by L. casei 001 was found to be an effective means of adding high value to low-grade Hidakombu.

ACS Style

Tetsuya Sekine; Hiroshi Nagai; Naoko Hamada-Sato. Antihypertensive and Probiotic Effects of Hidakakombu (Saccharina angustata) Fermented by Lacticaseibacillus casei 001. Foods 2021, 10, 2048 .

AMA Style

Tetsuya Sekine, Hiroshi Nagai, Naoko Hamada-Sato. Antihypertensive and Probiotic Effects of Hidakakombu (Saccharina angustata) Fermented by Lacticaseibacillus casei 001. Foods. 2021; 10 (9):2048.

Chicago/Turabian Style

Tetsuya Sekine; Hiroshi Nagai; Naoko Hamada-Sato. 2021. "Antihypertensive and Probiotic Effects of Hidakakombu (Saccharina angustata) Fermented by Lacticaseibacillus casei 001." Foods 10, no. 9: 2048.

Communication
Published: 23 February 2021 in Symmetry
Reads 0
Downloads 0

A novel symmetrical macrocyclic phthalate hexaester (1) and a known macrocyclic phthalate tetraester (2) were isolated during a natural product-exploring program on the cyanobacterium Moorea producens. Their structures were elucidated based on spectroscopic data, including nuclear magnetic resonance and high-resolution mass spectra. In the antibacterial activity test, compounds 1 and 2 showed no bioactivity at the concentrations tested.

ACS Style

Michiya Kamio; Weina Jiang; Hiroki Osada; Masayuki Fukuoka; Hajime Uchida; Ryuichi Watanabe; Toshiyuki Suzuki; Hiroshi Nagai. Isolation and Structure Elucidation of a Novel Symmetrical Macrocyclic Phthalate Hexaester. Symmetry 2021, 13, 361 .

AMA Style

Michiya Kamio, Weina Jiang, Hiroki Osada, Masayuki Fukuoka, Hajime Uchida, Ryuichi Watanabe, Toshiyuki Suzuki, Hiroshi Nagai. Isolation and Structure Elucidation of a Novel Symmetrical Macrocyclic Phthalate Hexaester. Symmetry. 2021; 13 (2):361.

Chicago/Turabian Style

Michiya Kamio; Weina Jiang; Hiroki Osada; Masayuki Fukuoka; Hajime Uchida; Ryuichi Watanabe; Toshiyuki Suzuki; Hiroshi Nagai. 2021. "Isolation and Structure Elucidation of a Novel Symmetrical Macrocyclic Phthalate Hexaester." Symmetry 13, no. 2: 361.

Original article
Published: 05 January 2021 in Fisheries Science
Reads 0
Downloads 0

The solitary European sea squirt Ascidiella aspersa was introduced to northern Japan, causing dense coverage of the aquacultured Japanese scallop Mizuhopecten yessoensis. There are concerns that allelopathy by the sea squirt will suppress the growth of the scallop. Herein, we studied the allelopathic and defensive potential of A. aspersa using hemolytic assay. An alkyl sulfate, viz. 3,7,11,15-tetramethyl-hexadecan-1,19-disulfate (1), was isolated as a hemolytic compound, and 1 showed mild toxicity against the Japanese scallop and brine shrimp.

ACS Style

Hiroshi Nagai; Shuya Shibahara; Ryoji Matsushima; Hajime Uchida; Makoto Kanamori; Yasuyuki Nogata; Michiya Kamio. Hemolytic compound 3,7,11,15-tetramethyl-hexadecan-1,19-disulfate found in the invasive European sea squirt Ascidiella aspersa. Fisheries Science 2021, 87, 145 -150.

AMA Style

Hiroshi Nagai, Shuya Shibahara, Ryoji Matsushima, Hajime Uchida, Makoto Kanamori, Yasuyuki Nogata, Michiya Kamio. Hemolytic compound 3,7,11,15-tetramethyl-hexadecan-1,19-disulfate found in the invasive European sea squirt Ascidiella aspersa. Fisheries Science. 2021; 87 (1):145-150.

Chicago/Turabian Style

Hiroshi Nagai; Shuya Shibahara; Ryoji Matsushima; Hajime Uchida; Makoto Kanamori; Yasuyuki Nogata; Michiya Kamio. 2021. "Hemolytic compound 3,7,11,15-tetramethyl-hexadecan-1,19-disulfate found in the invasive European sea squirt Ascidiella aspersa." Fisheries Science 87, no. 1: 145-150.

Journal article
Published: 17 February 2020 in Molecules
Reads 0
Downloads 0

Cubozoan nematocyst venoms contain known cytolytic and hemolytic proteins, but small molecule components have not been previously reported from cubozoan venom. We screened nematocyst extracts of Alatina alata and Chironex yamaguchii by LC-MS for the presence of small molecule metabolites. Three isomeric compounds, cnidarins 4A (1), 4B (2), and 4C (3), were isolated from venom extracts and characterized by NMR and MS, which revealed their planar structure as cyclic γ-linked tetraglutamic acids. The full configurational assignments were established by syntheses of all six possible stereoisomers, comparison of spectral data and optical rotations, and stereochemical analysis of derivatized degradation products. Compounds 1–3 were subsequently detected by LC-MS in tissues of eight other cnidarian species. The most abundant of these compounds, cnidarin 4A (1), showed no mammalian cell toxicity or hemolytic activity, which may suggest a role for these cyclic tetraglutamates in nematocyst discharge.

ACS Style

Justin Reinicke; Ryuju Kitatani; Shadi Sedghi Masoud; Kelly Kawabata Galbraith; Wesley Yoshida; Ayako Igarashi; Kazuo Nagasawa; Gideon Berger; Angel Yanagihara; Hiroshi Nagai; F. David Horgen. Isolation, Structure Determination, and Synthesis of Cyclic Tetraglutamic Acids from Box Jellyfish Species Alatina alata and Chironex yamaguchii. Molecules 2020, 25, 883 .

AMA Style

Justin Reinicke, Ryuju Kitatani, Shadi Sedghi Masoud, Kelly Kawabata Galbraith, Wesley Yoshida, Ayako Igarashi, Kazuo Nagasawa, Gideon Berger, Angel Yanagihara, Hiroshi Nagai, F. David Horgen. Isolation, Structure Determination, and Synthesis of Cyclic Tetraglutamic Acids from Box Jellyfish Species Alatina alata and Chironex yamaguchii. Molecules. 2020; 25 (4):883.

Chicago/Turabian Style

Justin Reinicke; Ryuju Kitatani; Shadi Sedghi Masoud; Kelly Kawabata Galbraith; Wesley Yoshida; Ayako Igarashi; Kazuo Nagasawa; Gideon Berger; Angel Yanagihara; Hiroshi Nagai; F. David Horgen. 2020. "Isolation, Structure Determination, and Synthesis of Cyclic Tetraglutamic Acids from Box Jellyfish Species Alatina alata and Chironex yamaguchii." Molecules 25, no. 4: 883.

Communication
Published: 22 January 2020 in Molecules
Reads 0
Downloads 0

A new aplysiatoxin derivative, neo-aplysiatoxin A (1), along with seven known compounds, neo-debromoaplysiatoxin A (2), dolastatin 3 (3), lyngbic acid (4), malyngamide M (5), hermitamide A (6), (−)-loliolide (7), and (+)-epiloliolide (8), was isolated from the Okinawan cyanobacterium Moorea producens. Their structures were elucidated on the basis of spectroscopic data, including high-resolution mass spectrometry and nuclear magnetic resonance. The compounds were evaluated for cytotoxic and diatom growth inhibition activities.

ACS Style

Mioko Kawaguchi; Masayuki Satake; Bo-Tao Zhang; Yue-Yun Xiao; Masayuki Fukuoka; Hajime Uchida; Hiroshi Nagai. Neo-Aplysiatoxin A Isolated from Okinawan Cyanobacterium Moorea Producens. Molecules 2020, 25, 457 .

AMA Style

Mioko Kawaguchi, Masayuki Satake, Bo-Tao Zhang, Yue-Yun Xiao, Masayuki Fukuoka, Hajime Uchida, Hiroshi Nagai. Neo-Aplysiatoxin A Isolated from Okinawan Cyanobacterium Moorea Producens. Molecules. 2020; 25 (3):457.

Chicago/Turabian Style

Mioko Kawaguchi; Masayuki Satake; Bo-Tao Zhang; Yue-Yun Xiao; Masayuki Fukuoka; Hajime Uchida; Hiroshi Nagai. 2020. "Neo-Aplysiatoxin A Isolated from Okinawan Cyanobacterium Moorea Producens." Molecules 25, no. 3: 457.

Communication
Published: 21 June 2019 in Toxins
Reads 0
Downloads 0

Cyanobacteria have been shown to produce a number of bioactive compounds, including toxins. Some bioactive compounds obtained from a marine cyanobacterium Moorea producens (formerly Lyngbya majuscula) have been recognized as drug leads; one of these compounds is aplysiatoxin. We have isolated various aplysiatoxin derivatives from a M. producens sample obtained from the Okinawan coastal area. The frozen sample was extracted with organic solvents. The ethyl acetate layer was obtained from the crude extracts via liquid-liquid partitioning, then separated by HPLC using a reversed-phase column. Finally, 1.1 mg of the compound was isolated. The chemical structure of the isolated compound was elucidated with spectroscopic methods, using HR-MS and 1D and 2D NMR techniques, and was revealed to be oscillatoxin I, a new member of the aplysiatoxin family. Oscillatoxin I showed cytotoxicity against the L1210 mouse lymphoma cell line and diatom growth-inhibition activity against the marine diatom Nitzschia amabilis.

ACS Style

Hiroshi Nagai; Shingo Sato; Kaori Iida; Kazutaka Hayashi; Mioko Kawaguchi; Hajime Uchida; Masayuki Satake. Oscillatoxin I: A New Aplysiatoxin Derivative, from a Marine Cyanobacterium. Toxins 2019, 11, 366 .

AMA Style

Hiroshi Nagai, Shingo Sato, Kaori Iida, Kazutaka Hayashi, Mioko Kawaguchi, Hajime Uchida, Masayuki Satake. Oscillatoxin I: A New Aplysiatoxin Derivative, from a Marine Cyanobacterium. Toxins. 2019; 11 (6):366.

Chicago/Turabian Style

Hiroshi Nagai; Shingo Sato; Kaori Iida; Kazutaka Hayashi; Mioko Kawaguchi; Hajime Uchida; Masayuki Satake. 2019. "Oscillatoxin I: A New Aplysiatoxin Derivative, from a Marine Cyanobacterium." Toxins 11, no. 6: 366.

Journal article
Published: 14 March 2019 in Tetrahedron
Reads 0
Downloads 0

The marine cyanobacterium Moorea producens is a rich source of diverse compounds that possess a variety of biological activities. In the present study, eight new aplysiatoxin derivatives, namely 6, 8–13, and 15, along with aplysiatoxin (1), debromoaplysiatoxin (2), 3-methoxyaplysiatoxin (3), anhydroaplysiatoxin (4), anhydrodebromoaplysiatoxin (5), oscillatoxin B2 (7), and 30-methyloscillatoxin D (14) were isolated and identified from the Okinawan M. producens. In cytotoxicity and diatom growth inhibition tests, the fifteen compounds tested (1–15) showed moderate or no activity at a concentration of 10 μg/mL.

ACS Style

Hiroshi Nagai; Minami Watanabe; Shingo Sato; Mioko Kawaguchi; Yue-Yun Xiao; Kazutaka Hayashi; Ryuichi Watanabe; Hajime Uchida; Masayuki Satake. New aplysiatoxin derivatives from the Okinawan cyanobacterium Moorea producens. Tetrahedron 2019, 75, 2486 -2494.

AMA Style

Hiroshi Nagai, Minami Watanabe, Shingo Sato, Mioko Kawaguchi, Yue-Yun Xiao, Kazutaka Hayashi, Ryuichi Watanabe, Hajime Uchida, Masayuki Satake. New aplysiatoxin derivatives from the Okinawan cyanobacterium Moorea producens. Tetrahedron. 2019; 75 (17):2486-2494.

Chicago/Turabian Style

Hiroshi Nagai; Minami Watanabe; Shingo Sato; Mioko Kawaguchi; Yue-Yun Xiao; Kazutaka Hayashi; Ryuichi Watanabe; Hajime Uchida; Masayuki Satake. 2019. "New aplysiatoxin derivatives from the Okinawan cyanobacterium Moorea producens." Tetrahedron 75, no. 17: 2486-2494.

Short communication
Published: 05 October 2017 in Phytochemistry Letters
Reads 0
Downloads 0

Chemical analysis of the hydrophilic fraction from marine cyanobacterium Moorea producens extracts led to the isolation of five new indole derivatives (1-5). So far, 2-formyl-4,5,6,7-tetrahydroindole has been reported only for 6 from the nature, consequently compounds 1-5 were the second representatives of this class. Cytotoxicity, diatom growth inhibition, and antibacterial activity tests for compounds 1-5 showed no bioactivity at the concentration tested.

ACS Style

Weina Jiang; Yingyue Bu; Mioko Kawaguchi; Hiroki Osada; Masayuki Fukuoka; Hajime Uchida; Ryuichi Watanabe; Toshiyuki Suzuki; Hiroshi Nagai. Five new indole derivatives from the cyanobacterium Moorea producens. Phytochemistry Letters 2017, 22, 163 -166.

AMA Style

Weina Jiang, Yingyue Bu, Mioko Kawaguchi, Hiroki Osada, Masayuki Fukuoka, Hajime Uchida, Ryuichi Watanabe, Toshiyuki Suzuki, Hiroshi Nagai. Five new indole derivatives from the cyanobacterium Moorea producens. Phytochemistry Letters. 2017; 22 ():163-166.

Chicago/Turabian Style

Weina Jiang; Yingyue Bu; Mioko Kawaguchi; Hiroki Osada; Masayuki Fukuoka; Hajime Uchida; Ryuichi Watanabe; Toshiyuki Suzuki; Hiroshi Nagai. 2017. "Five new indole derivatives from the cyanobacterium Moorea producens." Phytochemistry Letters 22, no. : 163-166.

Evaluation study
Published: 03 March 2016 in Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology
Reads 0
Downloads 0

Marine biofouling, which leads to significant operational stress and economic damage on marine infrastructures, is a major problem in marine related industries. Currently, the most common way to avoid marine biofouling involves the use of biocidal products in surface coatings. However, the need for environmentally friendly antibiofouling compounds has increased rapidly with the recent global prohibition of harmful antifoulants, such as tributyltin (TBT). In particular, periphytic diatoms have been shown to contribute significantly to biofilms, which play an important role in biofouling. Therefore, inhibiting the proliferation of fouling diatoms is a very important step in the prevention of marine biofouling. In this study, we developed a new, rapid, accurate, and convenient growth inhibition assay using the XTT colorimetric method to prevent the growth of the fouling periphytic diatom, Nitzschia amabilis Hidek. Suzuki (replaced synonym, Nitzschia laevis Hustedt). The feasibility of this method was verified by determining the growth inhibition activities of two standard photosynthetic inhibitors, DCMU and CuSO4. However, neither inhibitor had any cytotoxic activities at the range of concentrations tested. Moreover, this method was applied by screening and purification of herbicidic but non-cytotoxic compounds from cyanobacteria extracts. Our results demonstrate the utility of this newly established growth inhibition assay for the identification of marine anti-biofouling compounds.

ACS Style

Weina Jiang; Takuya Akagi; Hidekazu Suzuki; Ayaka Takimoto; Hiroshi Nagai. A new diatom growth inhibition assay using the XTT colorimetric method. Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology 2016, 185-186, 13 -19.

AMA Style

Weina Jiang, Takuya Akagi, Hidekazu Suzuki, Ayaka Takimoto, Hiroshi Nagai. A new diatom growth inhibition assay using the XTT colorimetric method. Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology. 2016; 185-186 ():13-19.

Chicago/Turabian Style

Weina Jiang; Takuya Akagi; Hidekazu Suzuki; Ayaka Takimoto; Hiroshi Nagai. 2016. "A new diatom growth inhibition assay using the XTT colorimetric method." Comparative Biochemistry and Physiology Part C: Toxicology & Pharmacology 185-186, no. : 13-19.

Journal article
Published: 01 January 2016 in Plankton and Benthos Research
Reads 0
Downloads 0

Jellyfish possess venomous cnidae on their tentacles to capture and consume marine zooplankton. Nevertheless, the planktonic larvae of the smooth fan lobster (Ibacus novemdentatus), known as phyllosoma, prey on jellyfish and successfully ingest both tentacle tissue as well as constituent cnidae, despite the presence of the venom-filled explosively penetrant cnidae or nematocysts. In the present study, we hypothesized that phyllosomas have mechanical and/or physiological resistance to internal envenomation by ingested nematocysts. To test this hypothesis, we examined the feces of phyllosomas (n=5) that were fed with Japanese sea nettle (Chrysaora pacifica) and found both undischarged as well as discharged cnidae surrounded by peritrophic membrane. We surmise that this membrane may mechanically insulate the lining of the midgut from stinging nematocysts to avoid injection of jellyfish venom into the phyllosomas’ body by nematocyst tubule penetration. We then tested physiological sensitivity of the phyllosomas (n=10) to crude extract of tentacle cnidae injected into their bodies. For this experiment, we used a crude venom extract prepared from nematocysts isolated from tentacles of a rhizostome jellyfish (Nemopilema nomurai) after exposure to high salt which disrupted tentacle integrity, and phosphate-buffered saline as a control. Nine out of 10 animals died after the injection of crude venom extract, while none of the animals died in the control group. These results indicate that the defense of phyllosoma larvae against the toxin of jellyfish is a combination of mechanical inactivation of the ingested nematocysts and chemical digestion of the toxin in the midgut rather than physiological resistance against the toxin.

ACS Style

Michiya Kamio; Kaori Wakabayashi; Hiroshi Nagai; Yuji Tanaka. Phyllosomas of smooth fan lobsters (Ibacus novemdentatus) encase jellyfish cnidae in peritrophic membranes in their feces. Plankton and Benthos Research 2016, 11, 100 -104.

AMA Style

Michiya Kamio, Kaori Wakabayashi, Hiroshi Nagai, Yuji Tanaka. Phyllosomas of smooth fan lobsters (Ibacus novemdentatus) encase jellyfish cnidae in peritrophic membranes in their feces. Plankton and Benthos Research. 2016; 11 (3):100-104.

Chicago/Turabian Style

Michiya Kamio; Kaori Wakabayashi; Hiroshi Nagai; Yuji Tanaka. 2016. "Phyllosomas of smooth fan lobsters (Ibacus novemdentatus) encase jellyfish cnidae in peritrophic membranes in their feces." Plankton and Benthos Research 11, no. 3: 100-104.

Journal article
Published: 01 December 2015 in Toxins
Reads 0
Downloads 0

Japanese scallops, Patinopecten yessoensis, were fed with the toxic dinoflagellate Dinophysis fortii to elucidate the relative magnitude of assimilation, accumulation, and metabolism of diarrhetic shellfish toxins (DSTs) and pectenotoxins (PTXs). Three individual scallops were separately exposed to cultured D. fortii for four days. The average cell number of D. fortii assimilated by each individual scallop was 7.7 × 105. Dinophysistoxin-1 (DTX1), pectenotoxin-2 (PTX2) and their metabolites were analyzed by liquid chromatography tandem mass spectrometry (LC/MS/MS) and the toxin content in individual tissues (digestive gland, adductor muscle, gill, gonad, mantle, and the others), feces and the seawater medium were quantified. Toxins were almost exclusively accumulated in the digestive gland with only low levels being detected in the gills, mantles, gonads, and adductor muscles. DTX1 and PTX2 were the dominant toxins in the D. fortii cells fed to the scallops, whereas the dominant toxins detected in the digestive gland of scallops were PTX6 and esterified acyl-O-DTX1 (DTX3). In other tissues PTX2 was the dominant toxin observed. The ratio of accumulated to assimilated toxins was 21%–39% and 7%–23% for PTXs and DTXs respectively. Approximately 54%–75% of PTX2 and 52%–70% of DTX1 assimilated by the scallops was directly excreted into the seawater mainly without metabolic transformation.

ACS Style

Ryoji Matsushima; Hajime Uchida; Satoshi Nagai; Ryuichi Watanabe; Michiya Kamio; Hiroshi Nagai; Masaki Kaneniwa; Toshiyuki Suzuki. Assimilation, Accumulation, and Metabolism of Dinophysistoxins (DTXs) and Pectenotoxins (PTXs) in the Several Tissues of Japanese Scallop Patinopecten yessoensis. Toxins 2015, 7, 5141 -5154.

AMA Style

Ryoji Matsushima, Hajime Uchida, Satoshi Nagai, Ryuichi Watanabe, Michiya Kamio, Hiroshi Nagai, Masaki Kaneniwa, Toshiyuki Suzuki. Assimilation, Accumulation, and Metabolism of Dinophysistoxins (DTXs) and Pectenotoxins (PTXs) in the Several Tissues of Japanese Scallop Patinopecten yessoensis. Toxins. 2015; 7 (12):5141-5154.

Chicago/Turabian Style

Ryoji Matsushima; Hajime Uchida; Satoshi Nagai; Ryuichi Watanabe; Michiya Kamio; Hiroshi Nagai; Masaki Kaneniwa; Toshiyuki Suzuki. 2015. "Assimilation, Accumulation, and Metabolism of Dinophysistoxins (DTXs) and Pectenotoxins (PTXs) in the Several Tissues of Japanese Scallop Patinopecten yessoensis." Toxins 7, no. 12: 5141-5154.

Research article
Published: 26 August 2015 in PLoS ONE
Reads 0
Downloads 0

A large number of humans are stung by jellyfish all over the world. The stings cause acute pain followed by persistent pain and local inflammation. Harmful jellyfish species typically cause strong pain, whereas harmless jellyfish cause subtle or no pain. Jellyfish sting humans by injecting a tubule, contained in the nematocyst, the stinging organ of jellyfish. The tubule penetrates into the skin leading to venom injection. The detailed morphology of the nematocyst tubule and molecular structure of the venom in the nematocyst has been reported; however, the mechanism responsible for the difference in pain that is caused by harmful and harmless jellyfish sting has not yet been explored or explained. Therefore, we hypothesized that differences in the length of the nematocyst tubule leads to different degrees of epithelial damage. The initial acute pain might be generated by penetration of the tubule, which stimulates pain receptor neurons, whilst persistent pain might be caused by injection of venom into the epithelium. To test this hypothesis we compared the lengths of discharged nematocyst tubules from harmful and harmless jellyfish species and evaluated their ability to penetrate human skin. The results showed that the harmful jellyfish species, Chrysaora pacifica, Carybdea brevipedalia, and Chironex yamaguchii, causing moderate to severe pain, have nematocyst tubules longer than 200 μm, compared with a jellyfish species that cause little or no pain, Aurelia aurita. The majority of the tubules of harmful jellyfishes, C. yamaguchii and C. brevipedalia, were sufficiently long to penetrate the human epidermis and physically stimulate the free nerve endings of Aδ pain receptor fibers around plexuses to cause acute pain and inject the venom into the human skin epithelium to cause persistent pain and inflammation.

ACS Style

Ryuju Kitatani; Mayu Yamada; Michiya Kamio; Hiroshi Nagai. Length Is Associated with Pain: Jellyfish with Painful Sting Have Longer Nematocyst Tubules than Harmless Jellyfish. PLoS ONE 2015, 10, e0135015 .

AMA Style

Ryuju Kitatani, Mayu Yamada, Michiya Kamio, Hiroshi Nagai. Length Is Associated with Pain: Jellyfish with Painful Sting Have Longer Nematocyst Tubules than Harmless Jellyfish. PLoS ONE. 2015; 10 (8):e0135015.

Chicago/Turabian Style

Ryuju Kitatani; Mayu Yamada; Michiya Kamio; Hiroshi Nagai. 2015. "Length Is Associated with Pain: Jellyfish with Painful Sting Have Longer Nematocyst Tubules than Harmless Jellyfish." PLoS ONE 10, no. 8: e0135015.

Journal article
Published: 01 January 2015 in Fundamental Toxicological Sciences
Reads 0
Downloads 0
ACS Style

Ryoji Matsushima; Saori Kikutsugi; Ryuichi Watanabe; Hajime Uchida; Takeshi Yasumoto; Hiroshi Nagai; Masaki Kaneniwa; Toshiyuki Suzuki. Comparison of cytotoxicity among pectenotoxin-2 and other oxidized pectenotoxins in a rat myoblast cell line (L6) and a human rhabdomyosarcoma cell line (RD). Fundamental Toxicological Sciences 2015, 2, 49 -54.

AMA Style

Ryoji Matsushima, Saori Kikutsugi, Ryuichi Watanabe, Hajime Uchida, Takeshi Yasumoto, Hiroshi Nagai, Masaki Kaneniwa, Toshiyuki Suzuki. Comparison of cytotoxicity among pectenotoxin-2 and other oxidized pectenotoxins in a rat myoblast cell line (L6) and a human rhabdomyosarcoma cell line (RD). Fundamental Toxicological Sciences. 2015; 2 (1):49-54.

Chicago/Turabian Style

Ryoji Matsushima; Saori Kikutsugi; Ryuichi Watanabe; Hajime Uchida; Takeshi Yasumoto; Hiroshi Nagai; Masaki Kaneniwa; Toshiyuki Suzuki. 2015. "Comparison of cytotoxicity among pectenotoxin-2 and other oxidized pectenotoxins in a rat myoblast cell line (L6) and a human rhabdomyosarcoma cell line (RD)." Fundamental Toxicological Sciences 2, no. 1: 49-54.

Communication
Published: 01 December 2014 in Marine Drugs
Reads 0
Downloads 0

The toxin-producing cyanobacterium, Moorea producens, is a known causative organism of food poisoning and seaweed dermatitis (also known as “swimmer’s itch”). Two new toxic compounds were isolated and structurally elucidated from an ethyl acetate extract of M. producens collected from Hawaii. Analyses of HR-ESI-MS and NMR spectroscopies, as well as optical rotations and CD spectra indicated two new lyngbyatoxin derivatives, 2-oxo-3(R)-hydroxy-lyngbyatoxin A (1) and 2-oxo-3(R)-hydroxy-13-N-desmethyl-lyngbyatoxin A (2). The cytotoxicity and lethal activities of 1 and 2 were approximately 10- to 150-times less potent than lyngbyatoxin A. Additionally, the binding activities of 1 and 2 possessed 10,000-times lower affinity for the protein kinase Cδ (PKCδ)-C1B peptide when compared to lyngbyatoxin A. These findings suggest that these new lyngbyatoxin derivatives may mediate their acute toxicities through a non-PKC activation pathway.

ACS Style

Weina Jiang; Satoshi Tan; Yusuke Hanaki; Kazuhiro Irie; Hajime Uchida; Ryuichi Watanabe; Toshiyuki Suzuki; Bryan Sakamoto; Michiya Kamio; Hiroshi Nagai. Two New Lyngbyatoxin Derivatives from the Cyanobacterium, Moorea producens. Marine Drugs 2014, 12, 5788 -5800.

AMA Style

Weina Jiang, Satoshi Tan, Yusuke Hanaki, Kazuhiro Irie, Hajime Uchida, Ryuichi Watanabe, Toshiyuki Suzuki, Bryan Sakamoto, Michiya Kamio, Hiroshi Nagai. Two New Lyngbyatoxin Derivatives from the Cyanobacterium, Moorea producens. Marine Drugs. 2014; 12 (12):5788-5800.

Chicago/Turabian Style

Weina Jiang; Satoshi Tan; Yusuke Hanaki; Kazuhiro Irie; Hajime Uchida; Ryuichi Watanabe; Toshiyuki Suzuki; Bryan Sakamoto; Michiya Kamio; Hiroshi Nagai. 2014. "Two New Lyngbyatoxin Derivatives from the Cyanobacterium, Moorea producens." Marine Drugs 12, no. 12: 5788-5800.

Communication
Published: 12 May 2014 in Marine Drugs
Reads 0
Downloads 0

Lyngbyatoxin A from the marine cyanobacterium Moorea producens (formerly Lyngbya majuscula) is known as the causative agent of “swimmer’s itch” with its highly inflammatory effect. A new toxic compound was isolated along with lyngbyatoxin A from an ethyl acetate extract of M. producens collected from Hawaii. Analyses of HR-ESI-MS and NMR spectroscopies revealed the isolated compound had the same planar structure with that of lyngbyatoxin A. The results of optical rotation and CD spectra indicated that the compound was a new lyngbyatoxin A derivative, 12-epi-lyngbyatoxin A (1). While 12-epi-lyngbyatoxin A showed comparable toxicities with lyngbyatoxin A in cytotoxicity and crustacean lethality tests, it showed more than 100 times lower affinity for protein kinase Cδ (PKCδ) using the PKCδ-C1B peptide when compared to lyngbyatoxin A.

ACS Style

Weina Jiang; Wei Zhou; Hajime Uchida; Masayuki Kikumori; Kazuhiro Irie; Ryuichi Watanabe; Toshiyuki Suzuki; Bryan Sakamoto; Michiya Kamio; Hiroshi Nagai. A New Lyngbyatoxin from the Hawaiian Cyanobacterium Moorea producens. Marine Drugs 2014, 12, 2748 -2759.

AMA Style

Weina Jiang, Wei Zhou, Hajime Uchida, Masayuki Kikumori, Kazuhiro Irie, Ryuichi Watanabe, Toshiyuki Suzuki, Bryan Sakamoto, Michiya Kamio, Hiroshi Nagai. A New Lyngbyatoxin from the Hawaiian Cyanobacterium Moorea producens. Marine Drugs. 2014; 12 (5):2748-2759.

Chicago/Turabian Style

Weina Jiang; Wei Zhou; Hajime Uchida; Masayuki Kikumori; Kazuhiro Irie; Ryuichi Watanabe; Toshiyuki Suzuki; Bryan Sakamoto; Michiya Kamio; Hiroshi Nagai. 2014. "A New Lyngbyatoxin from the Hawaiian Cyanobacterium Moorea producens." Marine Drugs 12, no. 5: 2748-2759.

Original article
Published: 10 April 2013 in Fisheries Science
Reads 0
Downloads 0

Many polypeptides isolated from shallow water cnidarian species have been utilized as valuable biochemical tools in both basic and applied biological sciences. Deepwater cnidarian species might be another potential resource for novel biochemical tools. However, because of limited access to cnidarian samples from deep-sea environments, bioactive polypeptides have never before been reported from this group. In this study, we collected twelve deep-sea jellyfish species (nine hydrozoans and three scyphozoans) using a plankton net that was specially designed for collecting deep-sea organisms, and prepared water-soluble extracts, presumably containing polypeptides, of these jellyfishes. The extracts were subjected to cytotoxicity, hemolytic activity, and crustacean lethal toxicity tests. In the cytotoxicity test, six out of the nine tested hydrozoan species showed activity. In the hemolytic activity test, only three hydrozoans showed activity and none of the scyphozoan jellyfishes showed activity. In the crustacean lethality test, two hydrozoan jellyfishes and all three of the tested scyphozoan jellyfishes showed lethal activity. These results revealed a high incidence of water-soluble bioactive substances occurring in these deep-sea jellyfishes. Furthermore, all the heat-treated and the methanol-treated crude jellyfish extracts lost their bioactivities. Thus, it is likely that the bioactive compounds in the water-soluble extracts were unstable polypeptides (proteins). This is the first published report on bioactivities in extracts from deep-sea jellyfishes.

ACS Style

Takenori Kawabata; Dhugal J. Lindsay; Minoru Kitamura; Satoshi Konishi; Jun Nishikawa; Shuhei Nishida; Michiya Kamio; Hiroshi Nagai. Evaluation of the bioactivities of water-soluble extracts from twelve deep-sea jellyfish species. Fisheries Science 2013, 79, 487 -494.

AMA Style

Takenori Kawabata, Dhugal J. Lindsay, Minoru Kitamura, Satoshi Konishi, Jun Nishikawa, Shuhei Nishida, Michiya Kamio, Hiroshi Nagai. Evaluation of the bioactivities of water-soluble extracts from twelve deep-sea jellyfish species. Fisheries Science. 2013; 79 (3):487-494.

Chicago/Turabian Style

Takenori Kawabata; Dhugal J. Lindsay; Minoru Kitamura; Satoshi Konishi; Jun Nishikawa; Shuhei Nishida; Michiya Kamio; Hiroshi Nagai. 2013. "Evaluation of the bioactivities of water-soluble extracts from twelve deep-sea jellyfish species." Fisheries Science 79, no. 3: 487-494.

Reviews
Published: 04 October 2012 in ChemInform
Reads 0
Downloads 0
ACS Style

Kazuhiro Irie; Masayuki Kikumori; Hiroaki Kamachi; Keisuke Tanaka; Akira Murakami; Ryo C. Yanagita; Harukuni Tokuda; Nobutaka Suzuki; Hiroshi Nagai; Kiyotake Suenaga; Et Al. Et Al.. ChemInform Abstract: Synthesis and Structure-Activity Studies of Simplified Analogues of Aplysiatoxin with Antiproliferative Activity Like Bryostatin-1. ChemInform 2012, 43, no -no.

AMA Style

Kazuhiro Irie, Masayuki Kikumori, Hiroaki Kamachi, Keisuke Tanaka, Akira Murakami, Ryo C. Yanagita, Harukuni Tokuda, Nobutaka Suzuki, Hiroshi Nagai, Kiyotake Suenaga, Et Al. Et Al.. ChemInform Abstract: Synthesis and Structure-Activity Studies of Simplified Analogues of Aplysiatoxin with Antiproliferative Activity Like Bryostatin-1. ChemInform. 2012; 43 (44):no-no.

Chicago/Turabian Style

Kazuhiro Irie; Masayuki Kikumori; Hiroaki Kamachi; Keisuke Tanaka; Akira Murakami; Ryo C. Yanagita; Harukuni Tokuda; Nobutaka Suzuki; Hiroshi Nagai; Kiyotake Suenaga; Et Al. Et Al.. 2012. "ChemInform Abstract: Synthesis and Structure-Activity Studies of Simplified Analogues of Aplysiatoxin with Antiproliferative Activity Like Bryostatin-1." ChemInform 43, no. 44: no-no.

Book chapter
Published: 08 March 2012 in Handbook of Marine Natural Products
Reads 0
Downloads 0

Many marine animals produce protein toxins that are used for both predation and protection from predators. It is known that venomous stings by specific fish and jellyfish are sometimes fatal. For many years, detailed characterization of the causative toxins has been hampered by their instability. In recent years, various protein toxins have been successfully isolated and characterized from marine venomous animals. These studies have revealed that marine protein toxins exhibit unique structures and biological activities. A novel protein toxin family from the box jellyfish, the membrane-attack complex/perforin (MACPF) protein toxins isolated from the sea anemone, DNase II toxins from the starfish, and a dermatopontin family toxin from fire coral are representatives of some of these unique toxins. In this chapter, the most current studies on protein toxins isolated from marine venomous animals are discussed.

ACS Style

Hiroshi Nagai. Marine Protein Toxins. Handbook of Marine Natural Products 2012, 1388 -1419.

AMA Style

Hiroshi Nagai. Marine Protein Toxins. Handbook of Marine Natural Products. 2012; ():1388-1419.

Chicago/Turabian Style

Hiroshi Nagai. 2012. "Marine Protein Toxins." Handbook of Marine Natural Products , no. : 1388-1419.

Original article
Published: 02 June 2009 in Fisheries Science
Reads 0
Downloads 0

A 20-kDa protein toxin (bandaporin) was isolated from the sea anemone Anthopleura asiatica (Actiniidae) using the precipitation of ammonium sulfate saturation, and ion-exchange and gel-permeation chromatographies. Bandaporin showed potent hemolytic activity (EC50 value: 8.8 ng/ml to 0.8% suspension of sheep red blood cells) and lethal toxicity to crayfish (LD100 value: 0.58 mg/kg). The hemolytic activity of bandaporin was inhibited specifically by sphingomyelin. Eight other tested membrane lipids, including cholesterol, and gangliosides GM1 and GM2, did not inhibit bandaporin hemolytic activity. Antimicrobial and phospholipase A2 (PLA2) activities were not detected in bandaporin. The complementary DNA (cDNA) encoding bandaporin was sequenced and the deduced amino acid sequence of bandaporin revealed that this actinoporin had not been previously characterized. Actinoporins are cytolytic peptide toxins that are widely distributed in Actiniidae and Stichodactylidae sea anemones. This study was the first characterization of an actinoporin from a sea anemone of the genus Anthopleura.

ACS Style

Yuuki Kohno; Hiroshi Satoh; Akiko Iguchi; Hiroshi Nagai. Characterization of a new hemolytic protein toxin from the sea anemone Anthopleura asiatica. Fisheries Science 2009, 75, 1049 -1054.

AMA Style

Yuuki Kohno, Hiroshi Satoh, Akiko Iguchi, Hiroshi Nagai. Characterization of a new hemolytic protein toxin from the sea anemone Anthopleura asiatica. Fisheries Science. 2009; 75 (4):1049-1054.

Chicago/Turabian Style

Yuuki Kohno; Hiroshi Satoh; Akiko Iguchi; Hiroshi Nagai. 2009. "Characterization of a new hemolytic protein toxin from the sea anemone Anthopleura asiatica." Fisheries Science 75, no. 4: 1049-1054.

Review
Published: 01 April 2009 in Tanpakushitsu kakusan koso. Protein, nucleic acid, enzyme
Reads 0
Downloads 0
ACS Style

Hiroshi Nagai. [Characterization of the proteinaceous toxins from marine venomous animals]. Tanpakushitsu kakusan koso. Protein, nucleic acid, enzyme 2009, 54, 1 .

AMA Style

Hiroshi Nagai. [Characterization of the proteinaceous toxins from marine venomous animals]. Tanpakushitsu kakusan koso. Protein, nucleic acid, enzyme. 2009; 54 (5):1.

Chicago/Turabian Style

Hiroshi Nagai. 2009. "[Characterization of the proteinaceous toxins from marine venomous animals]." Tanpakushitsu kakusan koso. Protein, nucleic acid, enzyme 54, no. 5: 1.