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Prof. Dr. Osamu Arakawa
Nagasaki University

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0 Instrumental Analysis
0 Tetrodotoxin
0 Marine Toxins
0 food poisoning
0 Saxitoxin

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Tetrodotoxin
Pufferfish
Saxitoxin
food poisoning
Instrumental Analysis

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Journal article
Published: 30 October 2020 in Toxins
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The species classification of Cambodian freshwater pufferfish is incomplete and confusing, and scientific information on their toxicity and toxin profile is limited. In the present study, to accumulate information on the phylogeny and toxin profile of freshwater pufferfish, and to contribute to food safety in Cambodia, we conducted simultaneous genetic-based phylogenetic and toxin analyses using freshwater pufferfish individuals collected from Phnom Penh and Kratie (designated PNH and KTI, respectively). Phylogenetic analysis of partial sequences of three mitochondrial genes (cytochrome b, 16S rRNA, and cytochrome c oxidase subunit I) determined for each fish revealed that PNH and KTI are different species in the genus Pao (designated Pao sp. A and Pao sp. B, respectively). A partial sequence of the nuclear tributyltin-binding protein type 2 (TBT-bp2) gene differentiated the species at the amino acid level. Instrumental analysis of the toxin profile revealed that both Pao sp. A and Pao sp. B possess saxitoxins (STXs), comprising STX as the main component. In Pao sp. A, the toxin concentration in each tissue was extremely high, far exceeding the regulatory limit for STXs set by the Codex Committee, whereas in Pao sp. B, only the skin contained high toxin concentrations. The difference in the STX accumulation ability between the two species with different TBT-bp2 sequences suggests that TBT-bp2 is involved in STX accumulation in freshwater pufferfish.

ACS Style

Hongchen Zhu; Akinori Yamada; Yui Goto; Linan Horn; Laymithuna Ngy; Minoru Wada; Hiroyuki Doi; Jong Lee; Tomohiro Takatani; Osamu Arakawa. Phylogeny and Toxin Profile of Freshwater Pufferfish (Genus Pao) Collected from 2 Different Regions in Cambodia. Toxins 2020, 12, 689 .

AMA Style

Hongchen Zhu, Akinori Yamada, Yui Goto, Linan Horn, Laymithuna Ngy, Minoru Wada, Hiroyuki Doi, Jong Lee, Tomohiro Takatani, Osamu Arakawa. Phylogeny and Toxin Profile of Freshwater Pufferfish (Genus Pao) Collected from 2 Different Regions in Cambodia. Toxins. 2020; 12 (11):689.

Chicago/Turabian Style

Hongchen Zhu; Akinori Yamada; Yui Goto; Linan Horn; Laymithuna Ngy; Minoru Wada; Hiroyuki Doi; Jong Lee; Tomohiro Takatani; Osamu Arakawa. 2020. "Phylogeny and Toxin Profile of Freshwater Pufferfish (Genus Pao) Collected from 2 Different Regions in Cambodia." Toxins 12, no. 11: 689.

Journal article
Published: 07 July 2020 in Toxins
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Paralytic shellfish toxins (PSTs) produced by Alexandrium catenella (formerly A. tamarense) in Korean coastal waters caused the deaths of four people (in 1986 and 1996) who consumed contaminated mussels (Mytilus edulis). This led to more detailed consideration of the risks of PST outbreaks and incidents in Korea, including the introduction of shellfish collection bans. In this study, we investigated the relationships between A. catenella population dynamics and PST accumulation in the mussel M. galloprovincialis. Discharges from the Nakdong River affect the environmental conditions along the Geoje coast, resulting in low salinity and high nutrient levels that trigger blooms of A. catenella. At the toxin peak on 24 April 2017, the toxins detected in A. catenella cells were C1, gonyautoxin (GTX)1 and GTX2, whereas the concentrations of PSTs in M. galloprovincialis were high and in the order of GTX4 > GTX1 > GTX3 > saxitoxin (STX) > GTX2 > neoSTX > decarbamoylgonyautoxin (dcGTX)2 > dc GTX3. The PST level in mussels was also high. At 15 °C, the PSTs are constantly found to be higher (10-fold higher in 2017 and 30-fold higher in 2018) than safe levels for human consumption (80 μg STX diHCl equivalents 100 g−1).

ACS Style

Seung Ho Baek; Jungmin Choi; Minji Lee; Bum Soo Park; Yuchengmin Zhang; Osamu Arakawa; Tomohiro Takatani; Joong-Kyun Jeon; Young Ok Kim. Change in Paralytic Shellfish Toxins in the Mussel Mytilus galloprovincialis Depending on Dynamics of Harmful Alexandrium catenella (Group I) in the Geoje Coast (South Korea) during Bloom Season. Toxins 2020, 12, 442 .

AMA Style

Seung Ho Baek, Jungmin Choi, Minji Lee, Bum Soo Park, Yuchengmin Zhang, Osamu Arakawa, Tomohiro Takatani, Joong-Kyun Jeon, Young Ok Kim. Change in Paralytic Shellfish Toxins in the Mussel Mytilus galloprovincialis Depending on Dynamics of Harmful Alexandrium catenella (Group I) in the Geoje Coast (South Korea) during Bloom Season. Toxins. 2020; 12 (7):442.

Chicago/Turabian Style

Seung Ho Baek; Jungmin Choi; Minji Lee; Bum Soo Park; Yuchengmin Zhang; Osamu Arakawa; Tomohiro Takatani; Joong-Kyun Jeon; Young Ok Kim. 2020. "Change in Paralytic Shellfish Toxins in the Mussel Mytilus galloprovincialis Depending on Dynamics of Harmful Alexandrium catenella (Group I) in the Geoje Coast (South Korea) during Bloom Season." Toxins 12, no. 7: 442.

Journal article
Published: 03 July 2020 in Toxins
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Pufferfish of the family Tetraodontidae possess tetrodotoxin (TTX) and/or saxitoxins (STXs), but the toxin ratio differs, depending on the genus or species. In the present study, to clarify the distribution profile of TTX and STXs in Tetraodontidae, we investigated the composition and intra-body distribution of the toxins in Canthigaster valentini. C. valentini specimens (four male and six female) were collected from Amami-Oshima Island, Kagoshima Prefecture, Japan, and the toxins were extracted from the muscle, liver, intestine, gallbladder, gonads, and skin. Analysis of the extracts for TTX by liquid chromatography tandem mass spectrometry and of STXs by high-performance liquid chromatography with post-column fluorescence derivatization revealed TTX, as well as a large amount of STXs, with neoSTX as the main component and dicarbamoylSTX and STX itself as minor components, in the skin and ovary. The toxins were also detected in the other tissues, but in much lower amounts than in the skin and ovary. The TTX/STX ratio varied greatly, depending on the tissue, but TTX was the major toxin component in the whole body, and STXs accounted for 25% and 13% of the total toxin amount in males and females, respectively. Like the marine pufferfish of the genus Arothron, C. valentini should be considered a pufferfish with considerable amounts of both TTX and STXs present simultaneously.

ACS Style

Hongchen Zhu; Takayuki Sonoyama; Misako Yamada; Wei Gao; Ryohei Tatsuno; Tomohiro Takatani; Osamu Arakawa. Co-Occurrence of Tetrodotoxin and Saxitoxins and Their Intra-Body Distribution in the Pufferfish Canthigaster valentini. Toxins 2020, 12, 436 .

AMA Style

Hongchen Zhu, Takayuki Sonoyama, Misako Yamada, Wei Gao, Ryohei Tatsuno, Tomohiro Takatani, Osamu Arakawa. Co-Occurrence of Tetrodotoxin and Saxitoxins and Their Intra-Body Distribution in the Pufferfish Canthigaster valentini. Toxins. 2020; 12 (7):436.

Chicago/Turabian Style

Hongchen Zhu; Takayuki Sonoyama; Misako Yamada; Wei Gao; Ryohei Tatsuno; Tomohiro Takatani; Osamu Arakawa. 2020. "Co-Occurrence of Tetrodotoxin and Saxitoxins and Their Intra-Body Distribution in the Pufferfish Canthigaster valentini." Toxins 12, no. 7: 436.

Journal article
Published: 02 March 2020 in Foods
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The inactivation and damage of histamine-forming bacteria (HFB), Enterobacter aerogenes and Staphylococcus capitis, in a 0.1 M potassium phosphate buffer (pH 6.8) and marlin meat slurry by high hydrostatic pressure (HHP) treatments were studied using viability measurement and scanning electron microscopy (SEM). HHP treatments showed first order destruction kinetics to E. aerogenes and S. capitis during the pressure holding period. HFB in marlin meat slurry had higher D values and were more resistant to HHP treatments than in phosphate buffer. In phosphate buffer, E. aerogenes had higher D values than S. capitis at >380 MPa of pressure, whereas the reverse trend was noticed at lower pressures (<380 MPa). In marlin meat slurry, S. capitis had a higher D value than E. aerogenes at the same treatment pressure, indicating that S. capitis was more resistant to HHP treatment. To our knowledge, this is the first report to demonstrate that HHP can be used to inactivate HFB, E. aerogenes, and S. capitis, by causing disruption to bacterial cell membrane and cell wall as demonstrated by SEM micrographs.

ACS Style

Yi-Chen Lee; Yung-Hsiang Tsai; Shao-Lan Chen; Hsien-Feng Kung; Osamu Arakawa; Cheng-I Wei. Inactivation and Damage of Histamine-Forming Bacteria by Treatment with High Hydrostatic Pressure. Foods 2020, 9, 266 .

AMA Style

Yi-Chen Lee, Yung-Hsiang Tsai, Shao-Lan Chen, Hsien-Feng Kung, Osamu Arakawa, Cheng-I Wei. Inactivation and Damage of Histamine-Forming Bacteria by Treatment with High Hydrostatic Pressure. Foods. 2020; 9 (3):266.

Chicago/Turabian Style

Yi-Chen Lee; Yung-Hsiang Tsai; Shao-Lan Chen; Hsien-Feng Kung; Osamu Arakawa; Cheng-I Wei. 2020. "Inactivation and Damage of Histamine-Forming Bacteria by Treatment with High Hydrostatic Pressure." Foods 9, no. 3: 266.

Journal article
Published: 27 November 2019 in Toxicon
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The tetrodotoxin (TTX) uptake ability of pufferfish Takifugu rubripes tissues and its growth-associated changes were investigated using an in vitro tissue slice incubation method. Tissue slices prepared from the liver, skin, and intestine of a non-toxic cultured adult T. rubripes (20 months old) and incubated with incubation buffer containing 25 μg/mL TTX for 1-48 h showed a time-dependent increase in the TTX content in all tissues. The TTX contents of the skin and intestine slices were comparable to or slightly higher than that of the liver slices, with a similar transition pattern, suggesting similar TTX uptake ability among the skin, intestine, and liver. The TTX uptake ability of the liver and intestine did not differ significantly between young (8 months old) and adult (20 months old) fish, but the skin slices of young fish took up approximately twice as much TTX as that of adult fish, suggesting that the TTX uptake ability of the skin is involved in the growth-dependent changes in the toxin distribution inside the body in T. rubripes. To estimate the TTX uptake pathway in each tissue, an immunohistochemical technique was used to observe temporal changes in the intra-tissue microdistribution of TTX during incubation. The findings suggested that TTX is transferred and accumulates from pancreatic exocrine cells to hepatic parenchymal cells in the liver, from connective tissues to basal cells in the skin, and from villi epithelial cells via the lamina propria to the muscle layer in the intestine.

ACS Style

Wei Gao; Misako Yamada; Rieko Ohki; Yuji Nagashima; Ryohei Tatsuno; Koichi Ikeda; Kentaro Kawatsu; Tomohiro Takatani; Osamu Arakawa. Evaluation of the tetrodotoxin uptake ability of pufferfish Takifugu rubripes tissues according to age using an in vitro tissue slice incubation method. Toxicon 2019, 174, 8 -12.

AMA Style

Wei Gao, Misako Yamada, Rieko Ohki, Yuji Nagashima, Ryohei Tatsuno, Koichi Ikeda, Kentaro Kawatsu, Tomohiro Takatani, Osamu Arakawa. Evaluation of the tetrodotoxin uptake ability of pufferfish Takifugu rubripes tissues according to age using an in vitro tissue slice incubation method. Toxicon. 2019; 174 ():8-12.

Chicago/Turabian Style

Wei Gao; Misako Yamada; Rieko Ohki; Yuji Nagashima; Ryohei Tatsuno; Koichi Ikeda; Kentaro Kawatsu; Tomohiro Takatani; Osamu Arakawa. 2019. "Evaluation of the tetrodotoxin uptake ability of pufferfish Takifugu rubripes tissues according to age using an in vitro tissue slice incubation method." Toxicon 174, no. : 8-12.

Journal article
Published: 30 September 2019 in Toxicon
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We tested whether tetrodotoxin (TTX) functions as a stress relieving substance in puffer fish. We orally administered TTX to the juveniles of hatchery-reared non-toxic tiger puffer Takifugu rubripes and measured the effects of TTX on brain corticotropin-releasing hormone (CRH) mRNA expression and plasma cortisol levels in comparison with effects in non-toxic juveniles. Firstly, the reciprocal connections of CRH and adrenocorticotropic hormone (ACTH) were confirmed by dual-label immunohistochemistry. CRH-immunoreactive (ir) cell bodies were detected in the hypothalamus and CRH-ir fibers were observed to project to ACTH-ir cells in the rostral pars distalis of the pituitary. Next, a TTX-containing diet (2.35 mouse units (517 ng)/g diet) or a non-toxic diet were fed to the fish for 28 days under a recirculating system. Standard length and body weight became significantly larger in the TTX-treated group. The degree of loss of the caudal fin, which is an indicator of the degree of agonistic interactions, where high values show a higher loss of caudal fin of a fish due to nipping by other individuals, was significantly lower in the TTX-treated group. Relative CRH mRNA expression levels in the brain and cortisol levels in the plasma were significantly lower in the TTX-treated group. These results indicate that TTX functions as a stress relieving substance by affecting the CRH-ACTH-cortisol axis and reducing agonistic interactions in tiger puffer juveniles.

ACS Style

Masafumi Amano; Noriko Amiya; Minami Takaoka; Haruka Sato; Tomohiro Takatani; Osamu Arakawa; Yoshitaka Sakakura. Tetrodotoxin functions as a stress relieving substance in juvenile tiger puffer Takifugu rubripes. Toxicon 2019, 171, 54 -61.

AMA Style

Masafumi Amano, Noriko Amiya, Minami Takaoka, Haruka Sato, Tomohiro Takatani, Osamu Arakawa, Yoshitaka Sakakura. Tetrodotoxin functions as a stress relieving substance in juvenile tiger puffer Takifugu rubripes. Toxicon. 2019; 171 ():54-61.

Chicago/Turabian Style

Masafumi Amano; Noriko Amiya; Minami Takaoka; Haruka Sato; Tomohiro Takatani; Osamu Arakawa; Yoshitaka Sakakura. 2019. "Tetrodotoxin functions as a stress relieving substance in juvenile tiger puffer Takifugu rubripes." Toxicon 171, no. : 54-61.

Journal article
Published: 10 August 2019 in Toxins
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To clarify the differences in toxin selectivity between marine and freshwater pufferfish, we conducted experiments in artificially reared nontoxic specimens of Takifugu pardalis (marine) and Pao suvattii (freshwater) using tetrodotoxin (TTX) and paralytic shellfish poison (PSP; decarbamoylsaxitoxin (dcSTX) or saxitoxin (STX)). T. pardalis specimens were administered feed homogenate containing TTX or dcSTX (dose of toxin, 55.2 nmol/fish) and P. suvattii specimens were administered feed homogenate containing TTX + STX (dose of each toxin, 19.2 nmol/fish) by oral gavage. The toxin content in the intestine, muscle, skin, liver, and gonads was quantified after 24 and 48 or 72 h. In T. pardalis, TTX administered into the intestine was absorbed into the body and transferred and retained mainly in the skin and liver, while dcSTX was hardly retained in the body, although it partly remained in the intestine. In strong contrast, in P. suvattii, little TTX remained in the body, whereas STX was absorbed into the body and was transferred and retained in the ovary and skin. The findings revealed that TTX/PSP selectivity differs between the marine species T. pardalis and the freshwater species P. suvattii. T. pardalis, which naturally harbors TTX, selectively accumulates TTX, and P. suvattii, which naturally harbors PSP, selectively accumulates PSP.

ACS Style

Wei Gao; Yoko Kanahara; Misako Yamada; Ryohei Tatsuno; Hiroyuki Yoshikawa; Hiroyuki Doi; Tomohiro Takatani; Osamu Arakawa. Contrasting Toxin Selectivity between the Marine Pufferfish Takifugu pardalis and the Freshwater Pufferfish Pao suvattii. Toxins 2019, 11, 470 .

AMA Style

Wei Gao, Yoko Kanahara, Misako Yamada, Ryohei Tatsuno, Hiroyuki Yoshikawa, Hiroyuki Doi, Tomohiro Takatani, Osamu Arakawa. Contrasting Toxin Selectivity between the Marine Pufferfish Takifugu pardalis and the Freshwater Pufferfish Pao suvattii. Toxins. 2019; 11 (8):470.

Chicago/Turabian Style

Wei Gao; Yoko Kanahara; Misako Yamada; Ryohei Tatsuno; Hiroyuki Yoshikawa; Hiroyuki Doi; Tomohiro Takatani; Osamu Arakawa. 2019. "Contrasting Toxin Selectivity between the Marine Pufferfish Takifugu pardalis and the Freshwater Pufferfish Pao suvattii." Toxins 11, no. 8: 470.

Journal article
Published: 15 July 2018 in NIPPON SUISAN GAKKAISHI
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ACS Style

Kogen Okita; Engkong Tan; Hina Satone; Shigeharu Kinoshita; Shuichi Asakawa; Daisuke Ojima; Hideki Yamazaki; Kazutaka Sakiyama; Tomohiro Takatani; Osamu Arakawa; Atsushi Hagiwara; Yoshitaka Sakakura. Transcriptome analysis of tetrodotoxin sensing and tetrodotoxin action in the central nervous system of tiger puffer Takifugu rubripes juveniles. NIPPON SUISAN GAKKAISHI 2018, 84, 586 -586.

AMA Style

Kogen Okita, Engkong Tan, Hina Satone, Shigeharu Kinoshita, Shuichi Asakawa, Daisuke Ojima, Hideki Yamazaki, Kazutaka Sakiyama, Tomohiro Takatani, Osamu Arakawa, Atsushi Hagiwara, Yoshitaka Sakakura. Transcriptome analysis of tetrodotoxin sensing and tetrodotoxin action in the central nervous system of tiger puffer Takifugu rubripes juveniles. NIPPON SUISAN GAKKAISHI. 2018; 84 (4):586-586.

Chicago/Turabian Style

Kogen Okita; Engkong Tan; Hina Satone; Shigeharu Kinoshita; Shuichi Asakawa; Daisuke Ojima; Hideki Yamazaki; Kazutaka Sakiyama; Tomohiro Takatani; Osamu Arakawa; Atsushi Hagiwara; Yoshitaka Sakakura. 2018. "Transcriptome analysis of tetrodotoxin sensing and tetrodotoxin action in the central nervous system of tiger puffer Takifugu rubripes juveniles." NIPPON SUISAN GAKKAISHI 84, no. 4: 586-586.

Journal article
Published: 01 June 2018 in Toxicon
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It is known that tetrodotoxin (TTX), also known as pufferfish toxin, is an extremely potent neurotoxin and had been detected in various taxa. However, the exact function of the toxin in TTX-bearing organisms has remained unclear. In Takifugu pufferfish species, it has been suggested that TTX is utilized to protect larvae from predators but no experimental proof exists. In the present study, we used pufferfish Takifugu alboplumbeus larvae from wild and cultured parents to determine the effects of the maternal TTX on the survival of toxic and non-toxic pufferfish larvae, respectively. TTX contents in the larval pufferfish differed between the larvae derived from wild and cultured parents (1.23 ± 0.20 ng/individual vs. undetectable levels, respectively). Immunohistochemical staining with anti-TTX monoclonal antibody demonstrated that the TTX-specific signals were primarily observed at the body surface of the larvae of wild parents, but not of cultured parents. Predation experiments demonstrated that the juveniles of Girella punctata and Chaenogobius gulosus, used as predator fish, ingested the pufferfish larvae derived from either type of parents, but instantly spat out those from wild parents only. These results indicate that larvae, which are at the most vulnerable stage in the life of pufferfish, are protected by maternal TTX.

ACS Style

Shiro Itoi; Miwa Suzuki; Kiyoshi Asahina; Eitaro Sawayama; Junki Nishikubo; Hikaru Oyama; Mitsuki Takei; Nanae Shiibashi; Tomohiro Takatani; Osamu Arakawa; Haruo Sugita. Role of maternal tetrodotoxin in survival of larval pufferfish. Toxicon 2018, 148, 95 -100.

AMA Style

Shiro Itoi, Miwa Suzuki, Kiyoshi Asahina, Eitaro Sawayama, Junki Nishikubo, Hikaru Oyama, Mitsuki Takei, Nanae Shiibashi, Tomohiro Takatani, Osamu Arakawa, Haruo Sugita. Role of maternal tetrodotoxin in survival of larval pufferfish. Toxicon. 2018; 148 ():95-100.

Chicago/Turabian Style

Shiro Itoi; Miwa Suzuki; Kiyoshi Asahina; Eitaro Sawayama; Junki Nishikubo; Hikaru Oyama; Mitsuki Takei; Nanae Shiibashi; Tomohiro Takatani; Osamu Arakawa; Haruo Sugita. 2018. "Role of maternal tetrodotoxin in survival of larval pufferfish." Toxicon 148, no. : 95-100.

Original article
Published: 09 May 2018 in Fisheries Science
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To clarify the maturation-associated accumulation profile of tetrodotoxin (TTX) in the female pufferfish Takifugu pardalis, specimens collected from Omura Bay, Nagasaki Prefecture, Japan, from November through December, 2014, were separated based on the histology of ovarian sections into four groups: yolk vesicle stage (Yv), yolk globule stage (Yg)-1, Yg-2, and Yg-3. TTX quantification in each tissue in each group by liquid chromatography–mass spectrometry revealed that the TTX concentration [mouse unit (MU)/g] in the ovary increased from Yv to Yg-1, and the TTX amount (MU/individual) in the ovary increased from Yg-1 through Yg-3. In Yv, TTX in the skin accounted for 86% of the total TTX in the body, whereas from Yg-1 through Yg-3, ovarian TTX accounted for 53–76% of the total. In female specimens collected from the same bay from February to May 2015, the TTX amount in the ovary markedly decreased after spawning, and the TTX amount in the liver increased. Immunohistochemical observation of the ovarian sections indicated that TTX localized mainly in the nucleus of immature oocytes, but then distributes to the yolk vesicles and yolk globules as maturation advances, and is partly transferred to the egg membrane as spawning approaches.

ACS Style

Wei Gao; Yoko Kanahara; Ryohei Tatsuno; Kiyoshi Soyano; Gregory Nishihara; Chisato Urata; Tomohiro Takatani; Osamu Arakawa. Maturation-associated changes in internal distribution and intra-ovarian microdistribution of tetrodotoxin in the pufferfish Takifugu pardalis. Fisheries Science 2018, 84, 723 -732.

AMA Style

Wei Gao, Yoko Kanahara, Ryohei Tatsuno, Kiyoshi Soyano, Gregory Nishihara, Chisato Urata, Tomohiro Takatani, Osamu Arakawa. Maturation-associated changes in internal distribution and intra-ovarian microdistribution of tetrodotoxin in the pufferfish Takifugu pardalis. Fisheries Science. 2018; 84 (4):723-732.

Chicago/Turabian Style

Wei Gao; Yoko Kanahara; Ryohei Tatsuno; Kiyoshi Soyano; Gregory Nishihara; Chisato Urata; Tomohiro Takatani; Osamu Arakawa. 2018. "Maturation-associated changes in internal distribution and intra-ovarian microdistribution of tetrodotoxin in the pufferfish Takifugu pardalis." Fisheries Science 84, no. 4: 723-732.

Journal article
Published: 17 October 2017 in Aqua-BioScience Monographs
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ACS Style

Osamu Arakawa; Tomohiro Takatani; Shigeto Taniyama; Ryohei Tatsuno. Toxins of Pufferfish—Distribution, Accumulation Mechanism, and Physiologic Functions. Aqua-BioScience Monographs 2017, 10, 41 -80.

AMA Style

Osamu Arakawa, Tomohiro Takatani, Shigeto Taniyama, Ryohei Tatsuno. Toxins of Pufferfish—Distribution, Accumulation Mechanism, and Physiologic Functions. Aqua-BioScience Monographs. 2017; 10 (3):41-80.

Chicago/Turabian Style

Osamu Arakawa; Tomohiro Takatani; Shigeto Taniyama; Ryohei Tatsuno. 2017. "Toxins of Pufferfish—Distribution, Accumulation Mechanism, and Physiologic Functions." Aqua-BioScience Monographs 10, no. 3: 41-80.

Journal article
Published: 25 September 2017 in Phycological Research
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The red alga Digenea simplex was cultured with various culture media to clarify the nutritional conditions to produce kainic acid (KA). Unlike the domoic acid-producing red alga Chondria armata, D. simplex was insensitive to excessive manganese, and grew best (mean growth rate approximately 800% for 25 days) in modified PES medium (mPES; seawater + nitrate, phosphate, iron, trace metals, vitamins, and 2-[4-(2-hydroxyethyl)-1-piperazinyl]- ethanesulfonic acid) prepared with autoclaved seawater. Liquid chromatography-mass spectrometry analysis of the algal extracts revealed that the KA content of the explants cultured with mPES or N·P·Fe medium (seawater + nitrate, phosphate, and iron) was somewhat higher than that of wild specimens (1748–2378 μg g−1 vs 1562 μg g−1). The 1H-nuclear magnetic resonance spectrum of the KA extracted and purified from pooled explants was indistinguishable from the previously reported KA spectrum. When D. simplex was cultured for 6 weeks with medium in which NaNO3 of mPES was replaced by Na15NO3, the ratio of 214KA to total measured KA (totalKA = 213KA + 214KA) in the cultured explants (0.1 at the beginning of culture) gradually increased to 2.5, indicating that D. simplex produces KA in proportion to its growth under the condition in which sufficient nitrogen source is available.

ACS Style

Shanshan Jiang; Kazuyoshi Kuwano; Gregory N. Nishihara; Chisato Urata; Ryusuke Shimoda; Tomohiro Takatani; Osamu Arakawa. Uptake of nitrogen and production of kainic acid by laboratory culture of the red alga Digenea simplex. Phycological Research 2017, 66, 68 -75.

AMA Style

Shanshan Jiang, Kazuyoshi Kuwano, Gregory N. Nishihara, Chisato Urata, Ryusuke Shimoda, Tomohiro Takatani, Osamu Arakawa. Uptake of nitrogen and production of kainic acid by laboratory culture of the red alga Digenea simplex. Phycological Research. 2017; 66 (1):68-75.

Chicago/Turabian Style

Shanshan Jiang; Kazuyoshi Kuwano; Gregory N. Nishihara; Chisato Urata; Ryusuke Shimoda; Tomohiro Takatani; Osamu Arakawa. 2017. "Uptake of nitrogen and production of kainic acid by laboratory culture of the red alga Digenea simplex." Phycological Research 66, no. 1: 68-75.

Journal article
Published: 01 May 2017 in Toxicon
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Tetrodotoxin (TTX) was intramuscularly administered to nontoxic cultured specimens of the pufferfish Takifugu rubripes to investigate differences in the toxin transfer and accumulation profiles between the skin and liver. Test fish were administered TTX at doses of 30 (Low dose; LD), 100 (Medium dose; MD), and 300 (High dose; HD) μg/individual, respectively. Liquid chromatography/mass spectrometry analysis for TTX revealed that the TTX concentration in both the skin (0.48-1.7 μg/g) and liver (0.43-6.0 μg/g) at 24 h after the toxin administration increased with an increase in the dose. The TTX accumulation ratio (ratio (%) of accumulated TTX in each tissue (μg/tissue) to the administered dose (μg/individual)) of the skin (11.1-38.6) significantly decreased with an increase in the dose, whereas that of the liver (18.4-21.3) was almost constant irrespective of the dose. Immunohistochemical observations of the skin sections revealed TTX-positive signals in basal cells in LD, but as the dose increased, TTX-positive signals were also observed in the epidermis. In the liver sections, TTX-positive signals were rarely observed in LD and MD, but the TTX was distributed throughout the liver tissue in HD.

ACS Style

Ryohei Tatsuno; Wei Gao; Kotaro Ibi; Tomoka Mine; Kogen Okita; Gregory Nishihara; Tomohiro Takatani; Osamu Arakawa. Profile differences in tetrodotoxin transfer to skin and liver in the pufferfish Takifugu rubripes. Toxicon 2017, 130, 73 -78.

AMA Style

Ryohei Tatsuno, Wei Gao, Kotaro Ibi, Tomoka Mine, Kogen Okita, Gregory Nishihara, Tomohiro Takatani, Osamu Arakawa. Profile differences in tetrodotoxin transfer to skin and liver in the pufferfish Takifugu rubripes. Toxicon. 2017; 130 ():73-78.

Chicago/Turabian Style

Ryohei Tatsuno; Wei Gao; Kotaro Ibi; Tomoka Mine; Kogen Okita; Gregory Nishihara; Tomohiro Takatani; Osamu Arakawa. 2017. "Profile differences in tetrodotoxin transfer to skin and liver in the pufferfish Takifugu rubripes." Toxicon 130, no. : 73-78.

Journal article
Published: 01 January 2016 in NIPPON SUISAN GAKKAISHI
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ACS Style

Tomohiro Takatani; Osamu Arakawa; Shigenori Suzuki; Noritaka Mochioka. 2. Toxicity of hybrid pufferfish. NIPPON SUISAN GAKKAISHI 2016, 82, 167 -167.

AMA Style

Tomohiro Takatani, Osamu Arakawa, Shigenori Suzuki, Noritaka Mochioka. 2. Toxicity of hybrid pufferfish. NIPPON SUISAN GAKKAISHI. 2016; 82 (2):167-167.

Chicago/Turabian Style

Tomohiro Takatani; Osamu Arakawa; Shigenori Suzuki; Noritaka Mochioka. 2016. "2. Toxicity of hybrid pufferfish." NIPPON SUISAN GAKKAISHI 82, no. 2: 167-167.

Journal article
Published: 01 January 2016 in NIPPON SUISAN GAKKAISHI
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ACS Style

Yuji Nagashima; Osamu Arakawa. Foreword. NIPPON SUISAN GAKKAISHI 2016, 82, 165 -165.

AMA Style

Yuji Nagashima, Osamu Arakawa. Foreword. NIPPON SUISAN GAKKAISHI. 2016; 82 (2):165-165.

Chicago/Turabian Style

Yuji Nagashima; Osamu Arakawa. 2016. "Foreword." NIPPON SUISAN GAKKAISHI 82, no. 2: 165-165.

Review article
Published: 11 November 2015 in Journal of Natural Products
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We have discovered new glycosylated fatty acid amides, stellettosides, from a Stelletta sp. marine sponge. They were detected through LC-MS analysis of the extract combined with the cytotoxicity assay of the prefractionated sample. Their planar structures were determined by analyses of the NMR and tandem FABMS data. Stellettosides A1 and A2 (1 and 2) as well as stellettosides B1–B4 (3–6) were obtained as inseparable mixtures. Careful analysis of the NMR and tandem FABMS data of each mixture, along with comparison of the tandem FABMS data with that of a synthetic model compound, permitted us to assign the structure of the constituents in the mixture. The absolute configuration of the monosaccharide unit was determined by LC-MS after chiral derivatization. The relative configurations of the vicinal oxygenated methines in the fatty acid chains were assigned by the 1H NMR data of the isopropylidene derivative. The mixture of stellettosides B1–B4 (3–6) exhibit moderate cytotoxic activity against HeLa cells with an IC50 value of 9 μM, whereas the mixture of stellettosides A1 and A2 (1 and 2) was not active at a concentration of 10 μM.

ACS Style

Victoria Peddie; Kentaro Takada; Shujiro Okuda; Yuji Ise; Yasuhiro Morii; Nobuhiro Yamawaki; Tomohiro Takatani; Osamu Arakawa; Shigeru Okada; Shigeki Matsunaga. Cytotoxic Glycosylated Fatty Acid Amides from a Stelletta sp. Marine Sponge. Journal of Natural Products 2015, 78, 2808 -2813.

AMA Style

Victoria Peddie, Kentaro Takada, Shujiro Okuda, Yuji Ise, Yasuhiro Morii, Nobuhiro Yamawaki, Tomohiro Takatani, Osamu Arakawa, Shigeru Okada, Shigeki Matsunaga. Cytotoxic Glycosylated Fatty Acid Amides from a Stelletta sp. Marine Sponge. Journal of Natural Products. 2015; 78 (11):2808-2813.

Chicago/Turabian Style

Victoria Peddie; Kentaro Takada; Shujiro Okuda; Yuji Ise; Yasuhiro Morii; Nobuhiro Yamawaki; Tomohiro Takatani; Osamu Arakawa; Shigeru Okada; Shigeki Matsunaga. 2015. "Cytotoxic Glycosylated Fatty Acid Amides from a Stelletta sp. Marine Sponge." Journal of Natural Products 78, no. 11: 2808-2813.

Journal article
Published: 01 January 2015 in NIPPON SUISAN GAKKAISHI
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Ryohei Tatsuno; Kenichi Yamaguchi; Koichi Ikeda; Tomohiro Takatani; Osamu Arakawa. III-1. Transfer/accumulation profile of tetrodotoxin and expression of TTX-binding proteins in pufferfish. NIPPON SUISAN GAKKAISHI 2015, 81, 734 -734.

AMA Style

Ryohei Tatsuno, Kenichi Yamaguchi, Koichi Ikeda, Tomohiro Takatani, Osamu Arakawa. III-1. Transfer/accumulation profile of tetrodotoxin and expression of TTX-binding proteins in pufferfish. NIPPON SUISAN GAKKAISHI. 2015; 81 (4):734-734.

Chicago/Turabian Style

Ryohei Tatsuno; Kenichi Yamaguchi; Koichi Ikeda; Tomohiro Takatani; Osamu Arakawa. 2015. "III-1. Transfer/accumulation profile of tetrodotoxin and expression of TTX-binding proteins in pufferfish." NIPPON SUISAN GAKKAISHI 81, no. 4: 734-734.

Journal article
Published: 01 December 2014 in Toxicon
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To clarify the production mechanisms and biologic functions of domoic acid (DA) by the red alga Chondria armata, we established a laboratory culture of C. armata. The alga grew better in modified PES medium (mPES) without trace metals or manganese than in unmodified mPES (seawater + nitrate, phosphate, iron, trace metals, vitamins, and 2-[4-(2-hydroxyethyl)-1-piperazinyl]-ethanesulfonic acid), suggesting that C. armata is especially hypersensitive to the toxicity of excessive manganese. C. armata cultured in N·P·Fe medium (seawater + nitrate, phosphate, and iron) grew best (mean growth rate 828.4%) at a relative nutrient concentration of 50%. Liquid chromatography-mass spectrometry analysis of the algal extracts revealed that the DA content of the cultured explants (2273-3308 ppm) was 4-5 fold higher than that of wild specimens. The extract of pooled explants (60 g) was purified by activated charcoal treatment and several types of column chromatography to afford ca. 10 mg DA. The 1H-nuclear magnetic resonance spectrum of the preparation was indistinguishable from the previously reported spectrum of DA, indicating that C. armata itself has an ability to produce DA

ACS Style

Shanshan Jiang; Kazuyoshi Kuwano; Nozomi Ishikawa; Michiko Yano; Tomohiro Takatani; Osamu Arakawa. Production of domoic acid by laboratory culture of the red alga Chondria armata. Toxicon 2014, 92, 1 -5.

AMA Style

Shanshan Jiang, Kazuyoshi Kuwano, Nozomi Ishikawa, Michiko Yano, Tomohiro Takatani, Osamu Arakawa. Production of domoic acid by laboratory culture of the red alga Chondria armata. Toxicon. 2014; 92 ():1-5.

Chicago/Turabian Style

Shanshan Jiang; Kazuyoshi Kuwano; Nozomi Ishikawa; Michiko Yano; Tomohiro Takatani; Osamu Arakawa. 2014. "Production of domoic acid by laboratory culture of the red alga Chondria armata." Toxicon 92, no. : 1-5.

Book chapter
Published: 28 August 2014 in Marine and Freshwater Toxins
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Pufferfish possess a potent neurotoxin, tetrodotoxin (TTX), and have caused human intoxications all over the world, especially in East Asia, where people have a time-honored food culture of eating pufferfish. TTX is distributed over a wide variety of organisms including flatworms, ribbon worms, mollusks, crustaceans, starfish, fish, and amphibians, and in the East Asian or Southeast Asian countries, TTX poisonings due to marine snails, horseshoe crabs, and gobies have also occasionally occurred, suggesting the possibility of further geographic expansion and/or diversification of TTX-bearing organisms caused by a change in the marine environment. The origin of TTX is likely certain species of marine bacteria, and many TTX-bearing organisms are toxified via the food chain that starts with the bacteria. Recently, valuable information regarding the dynamics of TTX taken up into the pufferfish body through food organisms, and the molecular mechanisms involved is accumulating, while TTX-bearing organisms are assumed to utilize TTX effectively for their survival, although TTX is a fatal toxin to organisms that possess no TTX. The present chapter describes the distribution of TTX in metazoans, and then introduces recent studies to clarify the intake of TTX to pufferfish liver using a pharmacokinetic model, and to reveal the transfer profile of TTX in pufferfish based on several TTX administration experiments. Moreover, after discussing on the potential physiologic functions of TTX in TTX-bearing organisms such as defense, offense, and attraction, human intoxications due to TTX will be summarized.

ACS Style

Yuji Nagashima; Osamu Arakawa. Pufferfish Poisoning and Tetrodotoxin. Marine and Freshwater Toxins 2014, 1 -21.

AMA Style

Yuji Nagashima, Osamu Arakawa. Pufferfish Poisoning and Tetrodotoxin. Marine and Freshwater Toxins. 2014; ():1-21.

Chicago/Turabian Style

Yuji Nagashima; Osamu Arakawa. 2014. "Pufferfish Poisoning and Tetrodotoxin." Marine and Freshwater Toxins , no. : 1-21.

Journal article
Published: 01 February 2014 in Toxicon
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Marine pufferfish contain tetrodotoxin (TTX), an extremely potent neurotoxin. All species of the genus Takifugu accumulate TTX in the liver and ovaries, although the tissue(s) in which it is localized can differ among species. TTX is the major defense strategy the pufferfish appears to use against predators. TTX is also used as a male-attracting pheromone during spawning. Here we demonstrate an additional (and unexpected) use of maternal TTX in the early larval stages of the Takifugu pufferfish. Predation experiments demonstrated that juveniles of all the species of fish used as predators ingested pufferfish larvae, but spat them out promptly. Liquid Chromatography-Tandem Mass Spectrometry (LC-MSMS) analysis revealed that the pufferfish larvae contain a small quantity of TTX, which is not enough to be lethal to the predators. Immunohistochemical analysis with anti-TTX monoclonal antibody revealed that the TTX is primarily localized in the body surface of the larvae as a layer of protection. Our study showed the female parent of the Takifugu pufferfish vertically transfers TTX to the larvae through its accumulation in the ovaries, and subsequent localization on the body surface of the larvae

ACS Style

Shiro Itoi; Saori Yoshikawa; Kiyoshi Asahina; Miwa Suzuki; Kento Ishizuka; Narumi Takimoto; Ryoko Mitsuoka; Naoto Yokoyama; Ayumi Detake; Chie Takayanagi; Miho Eguchi; Ryohei Tatsuno; Mitsuo Kawane; Shota Kokubo; Shihori Takanashi; Ai Miura; Katsuyoshi Suitoh; Tomohiro Takatani; Osamu Arakawa; Yoshitaka Sakakura; Haruo Sugita. Larval pufferfish protected by maternal tetrodotoxin. Toxicon 2014, 78, 35 -40.

AMA Style

Shiro Itoi, Saori Yoshikawa, Kiyoshi Asahina, Miwa Suzuki, Kento Ishizuka, Narumi Takimoto, Ryoko Mitsuoka, Naoto Yokoyama, Ayumi Detake, Chie Takayanagi, Miho Eguchi, Ryohei Tatsuno, Mitsuo Kawane, Shota Kokubo, Shihori Takanashi, Ai Miura, Katsuyoshi Suitoh, Tomohiro Takatani, Osamu Arakawa, Yoshitaka Sakakura, Haruo Sugita. Larval pufferfish protected by maternal tetrodotoxin. Toxicon. 2014; 78 ():35-40.

Chicago/Turabian Style

Shiro Itoi; Saori Yoshikawa; Kiyoshi Asahina; Miwa Suzuki; Kento Ishizuka; Narumi Takimoto; Ryoko Mitsuoka; Naoto Yokoyama; Ayumi Detake; Chie Takayanagi; Miho Eguchi; Ryohei Tatsuno; Mitsuo Kawane; Shota Kokubo; Shihori Takanashi; Ai Miura; Katsuyoshi Suitoh; Tomohiro Takatani; Osamu Arakawa; Yoshitaka Sakakura; Haruo Sugita. 2014. "Larval pufferfish protected by maternal tetrodotoxin." Toxicon 78, no. : 35-40.