1
|
Yonezawa R, Hayashi K, Oyama H, Yoshitake K, Sato S, Senevirathna JDM, Smith AR, Okabe T, Suo R, Kinoshita S, Takatani T, Arakawa O, Asakawa S, Itoi S. Tissue Localization of Tetrodotoxin in the Flatworm Planocera multitentaculata (Platyhelminthes: Polycladida). MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2024; 26:649-657. [PMID: 38861110 DOI: 10.1007/s10126-024-10332-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2024] [Accepted: 06/03/2024] [Indexed: 06/12/2024]
Abstract
Tetrodotoxin (TTX), a pufferfish toxin, is a highly potent neurotoxin that has been found in a wide variety of animals. The TTX-bearing flatworm Planocera multitentaculata possesses a large amount of TTX and is considered responsible for the toxification of TTX-bearing animals such as pufferfish (Takifugu and Chelonodon) and the toxic goby Yongeichthys criniger. However, the mechanism underlying TTX accumulation in flatworms remains unclear. Previous studies have been limited to identifying the distribution of TTX in multiple organs, such as the digestive organs, genital parts, and the remaining tissues of flatworms. Here, we performed liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis and immunohistochemical staining using a monoclonal anti-TTX antibody to elucidate the detailed localization of TTX in the tissues and organs of the flatworm P. multitentaculata. Immunohistochemical staining for P. multitentaculata showed that TTX-specific signals were detected not only in the ovaries and pharynx but also in many other tissues and organs, whereas no signal was detected in the brain, Lang's vesicle, and genitalia. In addition, combined with LC-MS/MS analysis, it was revealed for the first time that TTX accumulates in high concentrations in the basement membrane and epidermis. These findings robustly support the hypotheses of "TTX utilization protection from predators."
Collapse
Affiliation(s)
- Ryo Yonezawa
- Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Kentaro Hayashi
- Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Hikaru Oyama
- College of Bioresource Sciences, Nihon University, Kanagawa, Japan
- Biomedical Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki, 305-8566, Japan
| | - Kazutoshi Yoshitake
- Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Soshi Sato
- Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Jayan Duminda M Senevirathna
- Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
- Department of Animal Science, Faculty of Animal Science and Export Agriculture, Uva Wellassa University, Badulla, 90000, Sri Lanka
| | - Ashley R Smith
- Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Taiki Okabe
- College of Bioresource Sciences, Nihon University, Kanagawa, Japan
- Niigata Prefectural Kaiyo High School, Itoigawa, Niigata, 949-1352, Japan
| | - Rei Suo
- College of Bioresource Sciences, Nihon University, Kanagawa, Japan
| | - Shigeharu Kinoshita
- Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan
| | - Tomohiro Takatani
- Graduate School of Integrated Science and Technology, Nagasaki University, Nagasaki, 852-8521, Japan
| | - Osamu Arakawa
- Graduate School of Integrated Science and Technology, Nagasaki University, Nagasaki, 852-8521, Japan
| | - Shuichi Asakawa
- Department of Aquatic Bioscience, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan.
| | - Shiro Itoi
- College of Bioresource Sciences, Nihon University, Kanagawa, Japan.
| |
Collapse
|
2
|
Wassel MA, Makabe-Kobayashi Y, Iqbal MM, Takatani T, Sakakura Y, Hamasaki K. The impact of tetrodotoxin (TTX) on the gut microbiome in juvenile tiger pufferfish, Takifugu rubripes. Sci Rep 2024; 14:16684. [PMID: 39085277 PMCID: PMC11291987 DOI: 10.1038/s41598-024-66112-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2024] [Accepted: 06/27/2024] [Indexed: 08/02/2024] Open
Abstract
Tetrodotoxin (TTX) is a potent neurotoxin that accumulates in Takifugu rubripes, commonly known as pufferfish, through the ingestion of TTX-bearing organisms as part of their food chain. Although researchers believe that pufferfish use TTX to relieve stress, data are not currently available on how TTX affects the gut microbiota of pufferfish. To address this gap, our study aimed to investigate whether administering TTX to fish could alter their gut microbiota and overall health under various salinity conditions, including 30.0 ppt, 8.5 ppt, and 1.7 ppt salinity, which represent full-strength, isosmotic, and low-salinity stress, respectively. We analyzed the effect of TTX ingestion on the community structure, core microbiome, and metabolic capabilities of the gut microbiome using high-throughput sequencing technologies. The predominant bacterial taxa within the gut microbiome were Firmicutes (21-85%), Campilobacterota (2.8-67%), Spirochaetota (0.5-14%), and Proteobacteria (0.7-9.8%), with Mycoplasma, uncultured Arcobacteraceae, Brevinema, Vibrio, Rubritalea, and uncultured Pirellulaceae as core genera. Our findings indicated that the impact of TTX on high-abundance genera at 30.0 ppt and 8.5 ppt salinity levels was negligible, indicating their stability and resilience to TTX ingestion. However, at 1.7 ppt, TTX-fed fish showed a significant increase in uncultured Arcobacteraceae. Furthermore, our analysis of TTX-fed fish revealed taxonomic alterations in low-abundance taxa, which altered the predicted functions of the gut microbiota at all salinity levels. These results suggest that TTX administration could cause subtle effects on the metabolic functions of gut microbial communities. Overall, our study provides insights into the complex relationship between a TTX-accumulating animal, T. rubripes, and its gut microbiota.
Collapse
Affiliation(s)
- Mai A Wassel
- Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8564, Japan.
- Genetics and Genetic Engineering Research Group, National Institute of Oceanography and Fisheries, NIOF, Cairo, Egypt.
| | - Yoko Makabe-Kobayashi
- Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8564, Japan
| | - Md Mehedi Iqbal
- Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8564, Japan
| | - Tomohiro Takatani
- Graduate School of Integrated Science and Technology, Nagasaki University, 1‑14 Bunkyo, Nagasaki, 852‑8521, Japan
| | - Yoshitaka Sakakura
- Graduate School of Integrated Science and Technology, Nagasaki University, 1‑14 Bunkyo, Nagasaki, 852‑8521, Japan
| | - Koji Hamasaki
- Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8564, Japan.
- Collaborative Research Institute for Innovative Microbiology, The University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo, 113-8657, Japan.
- Department of Integrated Biosciences, Graduate School of Frontier Sciences, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba, 277-8562, Japan.
| |
Collapse
|
3
|
Wang Y, Javeed A, Jian C, Zeng Q, Han B. Precautions for seafood consumers: An updated review of toxicity, bioaccumulation, and rapid detection methods of marine biotoxins. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2024; 274:116201. [PMID: 38489901 DOI: 10.1016/j.ecoenv.2024.116201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2023] [Revised: 03/03/2024] [Accepted: 03/08/2024] [Indexed: 03/17/2024]
Abstract
Seafood products are globally consumed, and there is an increasing demand for the quality and safety of these products among consumers. Some seafoods are easily contaminated by marine biotoxins in natural environments or cultured farming processes. When humans ingest different toxins accumulated in seafood, they may exhibit different poisoning symptoms. According to the investigations, marine toxins produced by harmful algal blooms and various other marine organisms mainly accumulate in the body organs such as liver and digestive tract of seafood animals. Several regions around the world have reported incidents of seafood poisoning by biotoxins, posing a threat to human health. Thus, most countries have legislated to specify the permissible levels of these biotoxins in seafood. Therefore, it is necessary for seafood producers and suppliers to conduct necessary testing of toxins in seafood before and after harvesting to prohibit excessive toxins containing seafood from entering the market, which therefore can reduce the occurrence of seafood poisoning incidents. In recent years, some technologies which can quickly, conveniently, and sensitively detect biological toxins in seafood, have been developed and validated, these technologies have the potential to help seafood producers, suppliers and regulatory authorities. This article reviews the seafood toxins sources and types, mechanism of action and bioaccumulation of marine toxins, as well as legislation and rapid detection technologies for biotoxins in seafood for official and fishermen supervision.
Collapse
Affiliation(s)
- Yifan Wang
- Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, Laboratory of Antiallergic Functional Molecules, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, Zhejiang 310018, China
| | - Ansar Javeed
- Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, Laboratory of Antiallergic Functional Molecules, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, Zhejiang 310018, China
| | - Cuiqin Jian
- Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, Laboratory of Antiallergic Functional Molecules, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, Zhejiang 310018, China
| | - Qiuyu Zeng
- Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, Laboratory of Antiallergic Functional Molecules, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, Zhejiang 310018, China
| | - Bingnan Han
- Zhejiang Provincial Key Laboratory of Silkworm Bioreactor and Biomedicine, Laboratory of Antiallergic Functional Molecules, College of Life Sciences and Medicine, Zhejiang Sci-Tech University, Hangzhou, Zhejiang 310018, China.
| |
Collapse
|
4
|
Malykin GV, Velansky PV, Melnikova DI, Magarlamov TY. Tetrodotoxins in Larval Development of Ribbon Worm Cephalothrix cf. simula (Palaeonemertea, Nemertea). MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2023; 25:918-934. [PMID: 37672165 DOI: 10.1007/s10126-023-10249-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 08/31/2023] [Indexed: 09/07/2023]
Abstract
The toxic ribbon worm, Cephalothrix cf. simula (Palaeonemertea, Nemertea), possesses extremely high concentrations of tetrodotoxin (TTX). Although TTX has been found in the eggs of this species, the fate of the toxin in the ontogeny of the animal has not been explored. Here, using high performance liquid chromatography with tandem mass spectrometry and immunohistochemistry with anti-TTX antibodies, we examined levels, profile, and localization of TTX and its analogues (TTXs) in larvae of C. cf. simula throughout 41 days post-fertilization. A detailed investigation of cells in sites of TTX-accumulation was performed with light and electron microscopy. Newly hatched larvae possessed weak TTX-like immunoreactivity in all cells. With subsequent development, intensity of TTX-labeling in the ectodermal structures, mesodermal cells and apical cylinder of the apical gland increased. In the ectodermal structures, an intense TTX-labeling was observed in the multiciliated, type II granular, type I mucoid, and basal cells of the epidermis, and in the type III granular cells of the mouth gland. In the mesoderm, TTX was localized in the muscle and unigranular parenchyma-like cells. Eggs and larvae of C. cf. simula contained five TTXs, with two major toxins - TTX and 5,6,11-trideoxyTTX. Level and relative proportion of TTXs did not differ significantly among developmental stages, confirming that larvae obtained toxins from maternal eggs and were able to retain it. The results of this study provide insights into the formation of TTX-bearing apparatus of C. cf. simula through the larval development.
Collapse
Affiliation(s)
- Grigorii V Malykin
- A.V. Zhirmunsky National Scientific Center of Marine Biology, Far Eastern Branch, Russian Academy of Sciences, 690041, Vladivostok, Russian Federation
| | - Peter V Velansky
- A.V. Zhirmunsky National Scientific Center of Marine Biology, Far Eastern Branch, Russian Academy of Sciences, 690041, Vladivostok, Russian Federation
| | - Daria I Melnikova
- A.V. Zhirmunsky National Scientific Center of Marine Biology, Far Eastern Branch, Russian Academy of Sciences, 690041, Vladivostok, Russian Federation
| | - Timur Yu Magarlamov
- A.V. Zhirmunsky National Scientific Center of Marine Biology, Far Eastern Branch, Russian Academy of Sciences, 690041, Vladivostok, Russian Federation.
| |
Collapse
|
5
|
Amrullah A, Wahidah W, Ardiansyah A, Indrayani I. Transfer of maternal immunity using a polyvalent vaccine and offspring protection in Nile tilapia, Oreochromis niloticus. F1000Res 2023; 10:966. [PMID: 37767359 PMCID: PMC10521061 DOI: 10.12688/f1000research.52932.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/09/2023] [Indexed: 09/29/2023] Open
Abstract
Background Vaccination is an effective and alternative means of disease prevention, however, it cannot be conducted on the offspring of fish. For this process to take place, the transfer of maternal immunity should be implemented. This study aims to determine the effectiveness of transferring immunity from the broodstock to the offspring using a polyvalent vaccine against Aeromonas hydrophila, Streptococcus agalactiae, and Pseudomonas fluorescens in Nile tilapia, Oreochromis niloticus. Methods Nile tilapia broodstock with an average weight of 203g (±SD 23) was reared in spawning ponds until mass spawning and harvested one week post-spawning for vaccination. After being vaccinated according to the treatment, each fish broodstock was reared in 3x3 m cages installed in an earthen pond with a density of 20 broodstock, consisting of 15 females and 5 males. The vaccine used was a formalin-killed whole-cell vaccine at a density of 10 10 cfu/mL injected intramuscularly ( i.m.) at a dose of 0.4 mL/kg fish. Nile tilapia was injected with a vaccine used as a treatment. Example include A. hydrophila monovalent (MA) , S. agalactiae monovalent (MS) , P. fluorescens monovalent (MP), A. hydrophila and S. agalactiae bivalent (BAS) , A. hydrophila and P. fluorescens bivalent (BAP), P. fluorescens and S. agalactiae bivalent (BPS), and A. hydrophila, S. agalactiae, and P. fluorescens polyvalent vaccines (PAPS). While the control was fish that were injected with a PBS solution. The broodstock's immune response was observed on the 7 th, 14 th, 21 st, and 28 th days, while the immune response and challenge test on the offspring was conducted on the 10 th, 20 th, 30 th, and 40 th day during the post-hatching period. The parameters observed consisted of total leukocytes, phagocytic activity, antibody titer, lysozyme, and relative survival percentage (RPS). Result The application of PAPS in broodstock could significantly induce the best immune response and immunity to multiple diseases compared to other treatments. The RPS of the PAPS was also higher than the other types of vaccines. This showed that the transfer of immunity from the broodstock to the Nile tilapia offspring could protect it against bacterial diseases such as A. hydrophila, S. agalactiae, and P. fluorescens. Conclusion The application of polyvalent vaccine A. hydrophila, S. agalactiae, P. fluorescens vaccines increased the broodstock's immune response and it was transferred to their offsprings. Polyvalent vaccines derived from maternal immunity can protect offspring from disease up to 30 days of age. They were able to produce tilapia seeds that are immune to diseases caused by A. hydrophila, S. agalactiae, and P. fluorescens.
Collapse
Affiliation(s)
- Amrullah Amrullah
- Aquaculture, Pangkep State Polytechnic of Agriculture, Pangkep, South Sulawesi, 90655, Indonesia
| | - Wahidah Wahidah
- Aquaculture, Pangkep State Polytechnic of Agriculture, Pangkep, South Sulawesi, 90655, Indonesia
| | - Ardiansyah Ardiansyah
- Aquaculture, Pangkep State Polytechnic of Agriculture, Pangkep, South Sulawesi, 90655, Indonesia
| | - Indrayani Indrayani
- Agricultural Technology Education, Makassar State University, Makassar, South Sulawesi, Indonesia
| |
Collapse
|
6
|
Ito M, Shirai K, Oyama H, Yasukawa S, Asano M, Kihara M, Suo R, Sugita H, Nakahigashi R, Adachi M, Nishikawa T, Itoi S. Geographical differences in the composition of tetrodotoxin and 5,6,11-trideoxytetrodotoxin in Japanese pufferfishes and their origins. CHEMOSPHERE 2023; 336:139214. [PMID: 37327821 DOI: 10.1016/j.chemosphere.2023.139214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Revised: 06/02/2023] [Accepted: 06/11/2023] [Indexed: 06/18/2023]
Abstract
Tetrodotoxin (TTX)-bearing fish are thought to accumulate TTXs in their bodies through a food chain that begins with marine bacteria. However, the mechanism of TTXs transfer between prey and predators in the food chain remains unclear and the reasons for regional differences in pufferfish toxicity are also unknown. To investigate these matters, we collected juveniles of four species of pufferfish, Takifugu alboplumbeus, Takifugu flavipterus, Takifugu stictonotus, and Chelonodon patoca, from various locations in the Japanese Islands, and subjected them to liquid chromatography-tandem mass spectrometry analysis for TTX and its analog 5,6,11-trideoxyTTX (TDT). Concentrations of these substances tended to be higher in pufferfish juveniles collected from the Sanriku coastal area (Pacific coast of northern Japan) than in those from other locations. Juveniles had higher concentrations of TTX at all locations than of TDT. Mitochondrial cytochrome c oxidase subunit I (COI) sequences specific to the TTX-bearing flatworm, Planocera multitentaculata, were detected in the intestinal contents of up to 100% of pufferfish juveniles from various sampling sites, suggesting that P. multitentaculata was widely involved in the toxification of the juveniles in the coastal waters of Japan. A toxification experiment was conducted on three species of pufferfish juveniles (T. alboplumbeus, Takifugu rubripes and C. patoca) using TTX-bearing flatworm eggs harboring equal amounts of TTX and TDT. The TTX content of juveniles fed on flatworm eggs was found to be more than twice that of TDT, suggesting that pufferfish preferentially incorporate TTX compared to TDT.
Collapse
Affiliation(s)
- Masaaki Ito
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Kyoko Shirai
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Hikaru Oyama
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Shino Yasukawa
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Masaki Asano
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Masato Kihara
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Rei Suo
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Haruo Sugita
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Ryota Nakahigashi
- Laboratory of Organic Chemistry, Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya, Aichi, 464-8601, Japan
| | - Masaatsu Adachi
- Graduate School of Pharmaceutical Science, Tohoku University, Aoba, Aramaki, Aoba-ku, Sendai, 980-8587, Japan
| | - Toshio Nishikawa
- Laboratory of Organic Chemistry, Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya, Aichi, 464-8601, Japan
| | - Shiro Itoi
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan.
| |
Collapse
|
7
|
Asano M, Ishizaki C, Tomonou T, Kihara M, Ito M, Yasukawa S, Shirai K, Oyama H, Izawa S, Kawamura R, Saito K, Suo R, Nakahigashi R, Adachi M, Nishikawa T, Sugita H, Itoi S. Levels of Tetrodotoxins in Spawning Pufferfish, Takifugu alboplumbeus. Mar Drugs 2023; 21:md21040207. [PMID: 37103347 PMCID: PMC10141859 DOI: 10.3390/md21040207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2023] [Revised: 03/22/2023] [Accepted: 03/23/2023] [Indexed: 03/29/2023] Open
Abstract
Tetrodotoxin (TTX), also known as pufferfish toxin, is an extremely potent neurotoxin thought to be used as a biological defense compound in organisms bearing it. Although TTX was thought to function as a chemical agent for defense and anti-predation and an attractant for TTX-bearing animals including pufferfish, it has recently been demonstrated that pufferfish were also attracted to 5,6,11-trideoxyTTX, a related compound, rather than TTX alone. In this study, we attempted to estimate the roles of TTXs (TTX and 5,6,11-trideoxyTTX) in the pufferfish, Takifugu alboplumbeus, through examining the location of TTXs in various tissues of spawning pufferfish from Enoshima and Kamogawa, Japan. TTXs levels in the Kamogawa population were higher than those in the Enoshima population, and there was no significant difference in the amount of TTXs between the sexes in either population. Individual differences were greater in females than in males. However, the location of both substances in tissues differed significantly between sexes: male pufferfish accumulated most of their TTX in the skin and liver and most of their 5,6,11-trideoxyTTX in the skin, whereas females accumulated most of their TTX and 5,6,11-trideoxyTTX in the ovaries and skin.
Collapse
|
8
|
Oyama H, Ito M, Suo R, Goto-Inoue N, Morisasa M, Mori T, Sugita H, Mori T, Nakahigashi R, Adachi M, Nishikawa T, Itoi S. Changes in Tissue Distribution of Tetrodotoxin and Its Analogues in Association with Maturation in the Toxic Flatworm, Planocera multitentaculata. MARINE BIOTECHNOLOGY (NEW YORK, N.Y.) 2022; 24:1158-1167. [PMID: 36322281 DOI: 10.1007/s10126-022-10179-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 10/20/2022] [Indexed: 06/16/2023]
Abstract
The toxic flatworm, Planocera multitentaculata, possesses highly concentrated tetrodotoxin (TTX), also known as pufferfish toxin, throughout its life cycle, including the egg and larval stages. Additionally, TTX analogues, 5,6,11-trideoxyTTX and 11-norTTX-6(S)-ol, have also been detected in the flatworm. The high concentration of TTX in the eggs and larvae appears to be for protection against predation, and 11-norTTX-6(S)-ol in the pharyngeal tissue in the adults is likely used to sedate or kill prey during predation. However, information on the role of 5,6,11-trideoxyTTX, a potential important biosynthetic intermediate of TTX, in the toxic flatworm is lacking. Here, we aimed to determine the region of localization of TTX and its analogues in the flatworm body, understand their pharmacokinetics during maturation, and speculate on their function. Flatworm specimens in four stages of maturity, namely juvenile, mating, spawning, and late spawning, were subjected to LC-MS/MS analysis, using the pharyngeal tissue, oocytes in seminal receptacle, sperm, and tissue from 12 other sites. Although TTX was consistently high in the pharyngeal tissue throughout maturation, it was extremely high in the oocytes during the spawning period. Meanwhile, 5,6,11-trideoxyTTX was almost undetectable in the pharyngeal part throughout the maturation but was very abundant in the oocytes during spawning. 11-norTTX-6(S)-ol consistently localized in the pharyngeal tissue. Although the localization of TTX and its analogues was approximately consistent with the MS imaging data, TTX and 11-norTTX-6(S)-ol were found to be highly localized in the parenchyma surrounding the pharynx, which suggests the parenchyma is involved in the accumulation and production of TTXs.
Collapse
Affiliation(s)
- Hikaru Oyama
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Masaaki Ito
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Rei Suo
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Naoko Goto-Inoue
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Mizuki Morisasa
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Tsukasa Mori
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Haruo Sugita
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Tetsushi Mori
- Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, Koganei, Tokyo, 184-8588, Japan
| | - Ryota Nakahigashi
- Laboratory of Organic Chemistry, Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya, Aichi, 464-8601, Japan
| | - Masaatsu Adachi
- Graduate School of Pharmaceutical Sciences, Tohoku University, Aoba, Aramaki, Aoba-ku, Sendai, Miyagi, 980-8578, Japan
| | - Toshio Nishikawa
- Laboratory of Organic Chemistry, Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya, Aichi, 464-8601, Japan
| | - Shiro Itoi
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan.
| |
Collapse
|
9
|
Wu H, Hu Y, Wang J, Gong X, Bao B. Adaptive evolution of scn4aa in Takifugu and Tetraodon. AQUACULTURE AND FISHERIES 2022. [DOI: 10.1016/j.aaf.2022.10.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
|
10
|
Ogino Y, Yamaguchi A. Reduced lifetime fitness (growth, body condition and survivability) of hatchery-reared tiger pufferfish Takifugu rubripes compared to wild counterparts. JOURNAL OF FISH BIOLOGY 2022; 101:1270-1284. [PMID: 36054258 PMCID: PMC9826526 DOI: 10.1111/jfb.15199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/09/2022] [Accepted: 07/29/2022] [Indexed: 06/15/2023]
Abstract
Tiger pufferfish Takifugu rubripes (order Tetraodontiformes, family Tetraodontidae) is a highly exploited species and stocks continue to decline, although hatchery-reared juveniles have been released since 1965 for stock enhancement. To determine why the stock has not recovered through hatchery-release practices, this study investigated and compared the population characteristics of wild and hatchery-origin fish. The length-mass relationship showed that hatchery-origin fish were skinnier, with males weighing less than 90% of the mass of wild males of the same length. The hepatosomatic index tended to be lower in hatchery-origin fish. Age was estimated using the otolith-based method, and the estimates were more accurate and precise than those obtained by the conventional vertebra-based method. At the age of 2.9 years, an age at which specimens were the most abundant in catches, hatchery-origin males weighed only 67% of wild males. The maximum observed age was 12 years for wild fish and 5 years for hatchery-origin fish. The instantaneous total mortality rates of hatchery-origin fish were more than twice as high as those of wild fish. In summary, the hatchery-origin fish had poor health status, poor growth and high mortality, and their fitness in natural environments was therefore hypothesized to be low throughout life.
Collapse
Affiliation(s)
- Yoshimi Ogino
- Graduate School of Fisheries and Environmental SciencesNagasaki UniversityNagasakiJapan
| | - Atsuko Yamaguchi
- Graduate School of Fisheries and Environmental SciencesNagasaki UniversityNagasakiJapan
| |
Collapse
|
11
|
An almost nontoxic tetrodotoxin analog, 5,6,11-trideoxytetrodotoxin, as an odorant for the grass puffer. Sci Rep 2022; 12:15087. [PMID: 36064732 PMCID: PMC9445045 DOI: 10.1038/s41598-022-19355-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Accepted: 08/29/2022] [Indexed: 11/08/2022] Open
Abstract
Toxic puffers contain the potent neurotoxin, tetrodotoxin (TTX). Although TTX is considered to serve as a defense substance, previous behavioral studies have demonstrated that TTX acts as an attractive pheromone for some toxic puffers. To elucidate the physiological mechanism of putative pheromonal action of TTX, we examined whether grass puffers Takifugu alboplumbeus can detect TTX. Electroolfactogram (EOG) results suggest that the olfactory epithelium (OE) of grass puffers responded to a type of TTX analog (5,6,11-trideoxyTTX), although it did not respond to TTX. We also examined the attractive action of 5,6,11-trideoxyTTX on grass puffers by recording their swimming behavior under dark conditions. Grass puffers preferred to stay on the side of the aquarium where 5,6,11-trideoxyTTX was administered, and their swimming speed decreased. Additionally, odorant-induced labeling of olfactory sensory neurons by immunohistochemistry against neural activity marker (phosphorylated extracellular signal regulated kinase; pERK) revealed that labeled olfactory sensory neurons were localized in the region surrounding "islets" where there was considered as nonsensory epithelium. 5,6,11-trideoxyTTX has been known to accumulate in grass puffers, but its toxicity is much lower (almost nontoxic) than TTX. Our results suggest that toxic puffers may positively use this TTX analog, which has been present in their body with TTX but whose function was unknown, as an odorant for chemical communication or effective TTX accumulation.
Collapse
|
12
|
Zhang H, Li P, Wu B, Hou J, Ren J, Zhu Y, Xu J, Si F, Sun Z, Liu X. Transcriptomic analysis reveals the genes involved in tetrodotoxin (TTX) accumulation, translocation, and detoxification in the pufferfish Takifugu rubripes. CHEMOSPHERE 2022; 303:134962. [PMID: 35580645 DOI: 10.1016/j.chemosphere.2022.134962] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 05/04/2022] [Accepted: 05/10/2022] [Indexed: 06/15/2023]
Abstract
Tetrodotoxin (TTX) is a potent marine neurotoxin that exists in a variety of aquatic and terrestrial organisms. Pufferfish in different habitats show great variation in their TTX contents. Exploring the genes involved in TTX metabolism could contribute to our understanding of the molecular mechanisms underlying TTX accumulation, translocation, and detoxification in pufferfish. In this study, transcriptomic analysis was used to identify the functional genes related to TTX metabolism in the blood, liver, and muscle of the toxic and non-toxic tiger puffer (Takifugu rubripes). A total of 6101 differentially expressed genes (DEGs) were obtained after transcriptomic analysis; of these, 2401 were identified in the blood, 2262 in the liver, and 1438 in the muscle. After enrichment analysis, fourteen genes encoding glutathione S-transferases (GSTs), glutathione peroxidase (GPx), thioredoxins (TXNs), superoxide dismutase (SOD), ATP-binding cassettes (ABCs), apolipoproteins (APOs), inhibitors of apoptosis protein (IAP), and solute carrier (SLC), which are mainly antioxidant enzymes, membrane transporters, or anti-apoptotic factors, were revealed in the blood. Thirty-six genes encoding SLCs, ABCs, long-chain-fatty-acid-CoA ligases (ACSLs), interleukin 6 cytokine family signal transducer (IL6ST), endoplasmic reticulum (ER), and heat shock protein family A (Hsp70) were involved in transmembrane transporter activity and innate immune response. Notably, a large number of slc genes were found to play critical and diverse roles in TTX accumulation and translocation in the liver of T. rubripes. Nine genes from the slc, hsp70, complement C5 (c5), acsl, er, and serpin peptidase inhibitor (serpin) gene families were found to participate in the regulation of protein processing and anti-apoptosis. These results reflect the diverse functions of genes closely related to TTX accumulation, translocation, and detoxification in T. rubripes.
Collapse
Affiliation(s)
- Hanyuan Zhang
- Key Laboratory of Aquatic Genomics, Ministry of Agriculture and Rural Affairs, Beijing Key Laboratory of Fishery Biotechnology, Chinese Academy of Fishery Sciences, Beijing, 100141, China.
| | - Peizhen Li
- Key Laboratory of Aquatic Genomics, Ministry of Agriculture and Rural Affairs, Beijing Key Laboratory of Fishery Biotechnology, Chinese Academy of Fishery Sciences, Beijing, 100141, China
| | - Biyin Wu
- Key Laboratory of Aquatic Genomics, Ministry of Agriculture and Rural Affairs, Beijing Key Laboratory of Fishery Biotechnology, Chinese Academy of Fishery Sciences, Beijing, 100141, China
| | - Jilun Hou
- Beidaihe Central Experiment Station, Chinese Academy of Fishery Sciences, Qinhuangdao, Hebei, 066100, China
| | - Jiangong Ren
- Beidaihe Central Experiment Station, Chinese Academy of Fishery Sciences, Qinhuangdao, Hebei, 066100, China
| | - Youxiu Zhu
- Key Laboratory of Aquatic Genomics, Ministry of Agriculture and Rural Affairs, Beijing Key Laboratory of Fishery Biotechnology, Chinese Academy of Fishery Sciences, Beijing, 100141, China
| | - Jian Xu
- Key Laboratory of Aquatic Genomics, Ministry of Agriculture and Rural Affairs, Beijing Key Laboratory of Fishery Biotechnology, Chinese Academy of Fishery Sciences, Beijing, 100141, China
| | - Fei Si
- Beidaihe Central Experiment Station, Chinese Academy of Fishery Sciences, Qinhuangdao, Hebei, 066100, China
| | - Zhaohui Sun
- Beidaihe Central Experiment Station, Chinese Academy of Fishery Sciences, Qinhuangdao, Hebei, 066100, China
| | - Xia Liu
- Beidaihe Central Experiment Station, Chinese Academy of Fishery Sciences, Qinhuangdao, Hebei, 066100, China
| |
Collapse
|
13
|
Melnikova DI, Magarlamov TY. An Overview of the Anatomical Distribution of Tetrodotoxin in Animals. Toxins (Basel) 2022; 14:toxins14080576. [PMID: 36006238 PMCID: PMC9412668 DOI: 10.3390/toxins14080576] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 08/15/2022] [Accepted: 08/19/2022] [Indexed: 11/23/2022] Open
Abstract
Tetrodotoxin (TTX), a potent paralytic sodium channel blocker, is an intriguing marine toxin. Widely distributed in nature, TTX has attracted attention in various scientific fields, from biomedical studies to environmental safety concerns. Despite a long history of studies, many issues concerning the biosynthesis, origin, and spread of TTX in animals and ecosystems remain. This review aims to summarize the current knowledge on TTX circulation inside TTX-bearing animal bodies. We focus on the advances in TTX detection at the cellular and subcellular levels, providing an expanded picture of intra-organismal TTX migration mechanisms. We believe that this review will help address the gaps in the understanding of the biological function of TTX and facilitate the development of further studies involving TTX-bearing animals.
Collapse
|
14
|
He X, Wu H, Ye Y, Gong X, Bao B. Transcriptome analysis revealed gene expression feminization of testis after exogenous tetrodotoxin administration in pufferfish Takifugu flavidus. BMC Genomics 2022; 23:553. [PMID: 35922761 PMCID: PMC9347094 DOI: 10.1186/s12864-022-08787-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 07/22/2022] [Indexed: 11/29/2022] Open
Abstract
Tetrodotoxin (TTX) is a deadly neurotoxin and usually accumulates in large amounts in the ovaries but is non-toxic or low toxic in the testis of pufferfish. The molecular mechanism underlying sexual dimorphism accumulation of TTX in ovary and testis, and the relationship between TTX accumulation with sex related genes expression remain largely unknown. The present study investigated the effects of exogenous TTX treatment on Takifugu flavidus. The results demonstrated that exogenous TTX administration significantly incresed level of TTX concentration in kidney, cholecyst, skin, liver, heart, muscle, ovary and testis of the treatment group (TG) than that of the control group (CG). Transcriptome sequencing and analysis were performed to study differential expression profiles of mRNA and piRNA after TTX administration of the ovary and testis. The results showed that compared with female control group (FCG) and male control group (MCG), TTX administration resulted in 80 and 23 piRNAs, 126 and 223 genes up and down regulated expression in female TTX-treated group (FTG), meanwhile, 286 and 223 piRNAs, 2 and 443 genes up and down regulated expression in male TTX-treated group (MTG). The female dominant genes cyp19a1, gdf9 and foxl2 were found to be up-regulated in MTG. The cyp19a1, whose corresponding target piRNA uniq_554482 was identified as down-regulated in the MTG, indicating the gene expression feminization in testis after exogenous TTX administration. The KEGG enrichment analysis revealed that differentially expressed genes (DEGs) and piRNAs (DEpiRNAs) in MTG vs MCG group were more enriched in metabolism pathways, indicating that the testis produced more metabolic pathways in response to exogenous TTX, which might be a reason for the sexual dimorphism of TTX distribution in gonads. In addition, TdT-mediated dUTP-biotin nick end labeling staining showed that significant apoptosis was detected in the MTG testis, and the role of the cell apoptotic pathways was further confirmed. Overall, our research revealed that the response of the ovary and testis to TTX administration was largely different, the ovary is more tolerant whereas the testis is more sensitive to TTX. These data will deepen our understanding on the accumulation of TTX sexual dimorphism in Takifugu.
Collapse
Affiliation(s)
- Xue He
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources (Shanghai Ocean University), Ministry of Education; International Research Center for Marine Biosciences at Shanghai Ocean University, Ministry of Science and Technology; National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, 201306, China
| | - Hexing Wu
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources (Shanghai Ocean University), Ministry of Education; International Research Center for Marine Biosciences at Shanghai Ocean University, Ministry of Science and Technology; National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, 201306, China
| | - Yaping Ye
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources (Shanghai Ocean University), Ministry of Education; International Research Center for Marine Biosciences at Shanghai Ocean University, Ministry of Science and Technology; National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, 201306, China
| | - Xiaolin Gong
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources (Shanghai Ocean University), Ministry of Education; International Research Center for Marine Biosciences at Shanghai Ocean University, Ministry of Science and Technology; National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, 201306, China
| | - Baolong Bao
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources (Shanghai Ocean University), Ministry of Education; International Research Center for Marine Biosciences at Shanghai Ocean University, Ministry of Science and Technology; National Demonstration Center for Experimental Fisheries Science Education, Shanghai Ocean University, Shanghai, 201306, China.
| |
Collapse
|
15
|
Tetrodotoxin Retention in the Toxic Goby Yongeichthys criniger. JOURNAL OF MARINE SCIENCE AND ENGINEERING 2022. [DOI: 10.3390/jmse10020191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
To investigate tetrodotoxin (TTX) retention by the toxic goby Yongeichthys criniger, rearing experiments feeding nontoxic diets were conducted using 12 (Group I) and 17 (Group II) specimens collected from a natural environment. The specimens were reared in an aquarium with aeration and fed a diet lacking TTX for 60 days. Specimens were removed at 0, 20, 40, and 60 days (Group I) or 0, 30, and 60 days (Group II) after initiation of rearing. Liquid chromatography/mass spectrometry and liquid chromatography-tandem mass spectrometry revealed that whole-body concentrations and amounts of TTX decreased with increasing rearing duration in Group I. There were similar decreases in Group II, but the trend differed among tissues; the concentrations and amounts of TTX in the skin exhibited the greatest decreases. The results imply that Y. criniger has low TTX retention ability.
Collapse
|
16
|
Multi-Omics Analysis of Gene and Protein Candidates Possibly Related to Tetrodotoxin Accumulation in the Skin of Takifugu flavidus. Mar Drugs 2021; 19:md19110639. [PMID: 34822510 PMCID: PMC8621849 DOI: 10.3390/md19110639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 11/13/2021] [Accepted: 11/14/2021] [Indexed: 11/24/2022] Open
Abstract
Pufferfish is increasingly regarded by many as a delicacy. However, the tetrodotoxin (TTX) that accumulates in its body can be lethal upon consumption by humans. TTX is known to mainly accumulate in pufferfish skin, but the accumulation mechanisms are poorly understood. In this study, we aimed to explore the possible mechanism of TTX accumulation in the skin of the pufferfish Takifugu flavidus following treatment with TTX. Through liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis, we detected 37.3% of toxin accumulated in the skin at the end of the rearing period (168 h). Transcriptome and proteome analyses revealed the mechanism and pathways of TTX accumulation in the skin of T. flavidus in detail. Gene ontology and the Kyoto Encyclopedia of Genes and Genomes analyses strongly suggest that cardiac muscle contraction and adrenergic signaling in cardiomyocyte pathways play an important role in TTX accumulation. Moreover, some upregulated and downregulated genes, which were determined via RNA-Seq, were verified with qPCR analysis. This study is the first to use multi-omics profiling data to identify novel regulatory network mechanisms of TTX accumulation in the skin of pufferfish.
Collapse
|
17
|
Okabe T, Saito R, Yamamoto K, Watanabe R, Kaneko Y, Yanaoka M, Furukoshi S, Yasukawa S, Ito M, Oyama H, Suo R, Suzuki M, Takatani T, Arakawa O, Sugita H, Itoi S. The role of toxic planocerid flatworm larvae on tetrodotoxin accumulation in marine bivalves. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2021; 237:105908. [PMID: 34273772 DOI: 10.1016/j.aquatox.2021.105908] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 06/29/2021] [Accepted: 06/30/2021] [Indexed: 06/13/2023]
Abstract
Tetrodotoxin (TTX), also known as pufferfish toxin, has been detected in marine edible bivalves worldwide. In this study, several bivalve species, Azumapecten farreri subsp. akazara, Patinopecten yessoensis and Mytilus galloprovincialis, collected from the Pacific side of the northern Japanese Islands, were studied for the accumulation of TTX in the presence of toxic planocerid larvae. LC-MS/MS analysis demonstrated that TTX was detected only in the midgut gland of A. farreri subsp. akazara. Toxic flatworm-specific PCR and direct sequencing of the amplicons showed that the DNA fragments of the Planocera multitentaculata COI gene were detected in the gut contents of the toxified bivalves. The planocerid larvae were also detected in the environmental seawaters. Toxification experiments in the aquarium demonstrated that the mussel M. galloprovincialis was also toxified by feeding on the toxic flatworm larvae. These results suggest that the source of TTX accumulation in edible bivalves is toxic flatworm larvae.
Collapse
Affiliation(s)
- Taiki Okabe
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa 252-0880, Japan
| | - Rion Saito
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa 252-0880, Japan
| | - Kohei Yamamoto
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa 252-0880, Japan
| | - Riku Watanabe
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa 252-0880, Japan
| | - Yoshiki Kaneko
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa 252-0880, Japan
| | - Mutsumi Yanaoka
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa 252-0880, Japan
| | - Seika Furukoshi
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa 252-0880, Japan
| | - Shino Yasukawa
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa 252-0880, Japan
| | - Masaaki Ito
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa 252-0880, Japan
| | - Hikaru Oyama
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa 252-0880, Japan
| | - Rei Suo
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa 252-0880, Japan
| | - Miwa Suzuki
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa 252-0880, Japan
| | - Tomohiro Takatani
- Graduate School of Fisheries Science and Environmental Studies, Nagasaki University, Bunkyo 1-14, Nagasaki 852-8521, Japan
| | - Osamu Arakawa
- Graduate School of Fisheries Science and Environmental Studies, Nagasaki University, Bunkyo 1-14, Nagasaki 852-8521, Japan
| | - Haruo Sugita
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa 252-0880, Japan
| | - Shiro Itoi
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa 252-0880, Japan.
| |
Collapse
|
18
|
Molecular Characterization of the Von Willebrand Factor Type D Domain of Vitellogenin from Takifugu flavidus. Mar Drugs 2021; 19:md19040181. [PMID: 33806251 PMCID: PMC8065724 DOI: 10.3390/md19040181] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Revised: 03/22/2021] [Accepted: 03/24/2021] [Indexed: 01/21/2023] Open
Abstract
The von Willebrand factor type D (VWD) domain in vitellogenin has recently been found to bind tetrodotoxin. The way in which this protein domain associates with tetrodotoxin and participates in transporting tetrodotoxin in vivo remains unclear. A cDNA fragment of the vitellogenin gene containing the VWD domain from pufferfish (Takifugu flavidus) (TfVWD) was cloned. Using in silico structural and docking analyses of the predicted protein, we determined that key amino acids (namely, Val115, ASP116, Val117, and Lys122) in TfVWD mediate its binding to tetrodotoxin, which was supported by in vitro surface plasmon resonance analysis. Moreover, incubating recombinant rTfVWD together with tetrodotoxin attenuated its toxicity in vivo, further supporting protein–toxin binding and indicating associated toxicity-neutralizing effects. Finally, the expression profiling of TfVWD across different tissues and developmental stages indicated that its distribution patterns mirrored those of tetrodotoxin, suggesting that TfVWD may be involved in tetrodotoxin transport in pufferfish. For the first time, this study reveals the amino acids that mediate the binding of TfVWD to tetrodotoxin and provides a basis for further exploration of the molecular mechanisms underlying the enrichment and transfer of tetrodotoxin in pufferfish.
Collapse
|
19
|
Berlinck RGS, Bernardi DI, Fill T, Fernandes AAG, Jurberg ID. The chemistry and biology of guanidine secondary metabolites. Nat Prod Rep 2020; 38:586-667. [PMID: 33021301 DOI: 10.1039/d0np00051e] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Covering: 2017-2019Guanidine natural products isolated from microorganisms, marine invertebrates and terrestrial plants, amphibians and spiders, represented by non-ribosomal peptides, guanidine-bearing polyketides, alkaloids, terpenoids and shikimic acid derived, are the subject of this review. The topics include the discovery of new metabolites, total synthesis of natural guanidine compounds, biological activity and mechanism-of-action, biosynthesis and ecological functions.
Collapse
Affiliation(s)
- Roberto G S Berlinck
- Instituto de Química de São Carlos, Universidade de São Paulo, CP 780, CEP 13560-970, São Carlos, SP, Brazil.
| | | | | | | | | |
Collapse
|
20
|
Itoi S, Sato T, Takei M, Yamada R, Ogata R, Oyama H, Teranishi S, Kishiki A, Wada T, Noguchi K, Abe M, Okabe T, Akagi H, Kashitani M, Suo R, Koito T, Takatani T, Arakawa O, Sugita H. The planocerid flatworm is a main supplier of toxin to tetrodotoxin-bearing fish juveniles. CHEMOSPHERE 2020; 249:126217. [PMID: 32088461 DOI: 10.1016/j.chemosphere.2020.126217] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Revised: 02/11/2020] [Accepted: 02/13/2020] [Indexed: 06/10/2023]
Abstract
Tetrodotoxin (TTX), a potent neurotoxin, is found in various phylogenetically diverse taxa. In marine environments, the pufferfish is at the top of the food chain among TTX-bearing organisms. The accumulation of TTX in the body of pufferfish appears to be of the food web that begins with bacteria. It is known that toxic pufferfishes possess TTX from the larval/juvenile stage. However, the source of the TTX is unknown because the maternally sourced TTX is extremely small in quantity. Therefore, the TTX has to be obtained from other organisms or directly from the environment. Here, we report evidence that the source of TTX for toxic fish juveniles including the pufferfish (Chelonodon patoca) and the goby (Yongeichthys criniger) is in the food organisms, as seen in their gut contents. Next generation sequencing analysis for the mitochondrial COI gene showed that the majority of the sequence recovered from intestinal contents of these toxic fishes belonged to the flatworm Planocera multitentaculata, a polyclad flatworm containing highly concentrated TTX from the larval stage. PCR specific to P. multitentaculata also showed that DNA encoding the planocerid COI gene was strongly detected in the intestinal contents of the goby and pufferfish juveniles. Additionally, the planocerid specific COI sequence was detected in the environmental seawater collected from the water around the sampling locations for TTX-bearing fish. These results suggest that planocerid larvae are the major TTX supplier for juveniles of TTX-bearing fish species.
Collapse
Affiliation(s)
- Shiro Itoi
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan.
| | - Tatsunori Sato
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Mitsuki Takei
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Riko Yamada
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Ryuya Ogata
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Hikaru Oyama
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Shun Teranishi
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Ayano Kishiki
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Takenori Wada
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Kaede Noguchi
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Misato Abe
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Taiki Okabe
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Hiroyuki Akagi
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Maho Kashitani
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Rei Suo
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Tomoko Koito
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Tomohiro Takatani
- Graduate School of Fisheries Science and Environmental Studies, Nagasaki University, Bunkyo 1-14, Nagasaki, 852-8521, Japan
| | - Osamu Arakawa
- Graduate School of Fisheries Science and Environmental Studies, Nagasaki University, Bunkyo 1-14, Nagasaki, 852-8521, Japan
| | - Haruo Sugita
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| |
Collapse
|
21
|
Zhang X, Zong J, Chen S, Li M, Lu Y, Wang R, Xu H. Accumulation and Elimination of Tetrodotoxin in the Pufferfish Takifugu obscurus by Dietary Administration of the Wild Toxic Gastropod Nassarius semiplicata. Toxins (Basel) 2020; 12:toxins12050278. [PMID: 32344936 PMCID: PMC7290894 DOI: 10.3390/toxins12050278] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 04/23/2020] [Accepted: 04/23/2020] [Indexed: 12/21/2022] Open
Abstract
To investigate pufferfish accumulation, elimination, and distribution of tetrodotoxin (TTX), Takifugu obscurus was fed with wild TTX-containing gastropod Nassarius semiplicata to simulate the natural food chain. Three-month-old non-poisonous T. obscurus was fed with wild toxic N. semiplicata at three exposure dose for 28 days, and later, with toxin-free food until day 67. Three fish individuals from each treatment were sampled, and the distribution of TTX in different tissues was measured. The results showed that the accumulation ratio of TTX in the three exposure dose groups ranged from 35.76% to 40.20%. The accumulation ratio in the skin and liver was the highest amongst all tissues, accounting for more than 85% of the total TTX, whereas that in the kidney and gallbladder was the lowest (0.11–0.78%). Studies on the kinetic of TTX accumulation and elimination revealed that the skin was the tissue with the highest accumulation speed constant (8.06), while the liver, kidney, and intestinal tract showed the highest speed of TTX elimination. The time required for TTX reduction to reach the safety limit could be predicted by using standard elimination equations. Qualitative analysis by UPLC-MS/MS revealed the occurrence of seven TTX derivatives in T. obscurus; of these TTX, 5-deoxy TTX, 11-deoxy TTX, 4,9-anhydro TTX were found in all tested tissues.
Collapse
Affiliation(s)
- Xiaojun Zhang
- Laboratory of Aquatic Product Processing and Quality Safety, Marine Fisheries Research Institute of Zhejiang, Zhoushan 316100, China; (X.Z.); (S.C.)
- Zhejiang Province Key Lab of Mariculture & Enhancement, Zhoushan 316100, China
| | - Jingjing Zong
- School of Food and Pharmacy, Zhejiang Ocean University, Zhoushan 316022, China; (J.Z.); (Y.L.); (R.W.)
| | - Si Chen
- Laboratory of Aquatic Product Processing and Quality Safety, Marine Fisheries Research Institute of Zhejiang, Zhoushan 316100, China; (X.Z.); (S.C.)
- Zhejiang Province Key Lab of Mariculture & Enhancement, Zhoushan 316100, China
| | - Menglong Li
- Quality and Standard Research Center, Chinese Academy of Fishery Sciences, Beijing 100141, China;
| | - Yibo Lu
- School of Food and Pharmacy, Zhejiang Ocean University, Zhoushan 316022, China; (J.Z.); (Y.L.); (R.W.)
| | - Ruirui Wang
- School of Food and Pharmacy, Zhejiang Ocean University, Zhoushan 316022, China; (J.Z.); (Y.L.); (R.W.)
| | - Hanxiang Xu
- Laboratory of Aquatic Product Processing and Quality Safety, Marine Fisheries Research Institute of Zhejiang, Zhoushan 316100, China; (X.Z.); (S.C.)
- School of Food and Pharmacy, Zhejiang Ocean University, Zhoushan 316022, China; (J.Z.); (Y.L.); (R.W.)
- Correspondence: ; Tel.: +86-0580-2299-882
| |
Collapse
|
22
|
Itoi S, Tabuchi S, Abe M, Ueda H, Oyama H, Ogata R, Okabe T, Kishiki A, Sugita H. Difference in tetrodotoxin content between two sympatric planocerid flatworms, Planocera multitentaculata and Planocera reticulata. Toxicon 2019; 173:57-61. [PMID: 31778684 DOI: 10.1016/j.toxicon.2019.11.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Accepted: 11/24/2019] [Indexed: 11/20/2022]
Abstract
Planocerid flatworms and the related species (Platyhelminthes: polycladida) are known as tetrodotoxin (TTX)-bearing organisms, and they contribute to toxification of marine organisms at higher trophic levels, such as pufferfish and sea slugs. However, little is known of their biology or ecology. In this study, we therefore investigated the occurrence and toxicity of two sympatric planocerids, Planocera multitentaculata and Planocera reticulata, in intertidal zones of the central region of mainland Honshu, Japanese Islands. Planocera multitentaculata was much more abundant than P. reticulata. Body weight was greater in P. multitentaculata than in P. reticulata. Although a significant difference in TTX concentration was not observed between the two species, total TTX content per individual was greater in P. multitentaculata.
Collapse
Affiliation(s)
- Shiro Itoi
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan.
| | - Sora Tabuchi
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Misato Abe
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Hiroyuki Ueda
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Hikaru Oyama
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Ryuya Ogata
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Taiki Okabe
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Ayano Kishiki
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Haruo Sugita
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| |
Collapse
|
23
|
Okabe T, Oyama H, Kashitani M, Ishimaru Y, Suo R, Sugita H, Itoi S. Toxic Flatworm Egg Plates Serve as a Possible Source of Tetrodotoxin for Pufferfish. Toxins (Basel) 2019; 11:E402. [PMID: 31373322 PMCID: PMC6669758 DOI: 10.3390/toxins11070402] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 07/09/2019] [Accepted: 07/10/2019] [Indexed: 11/26/2022] Open
Abstract
The pufferfish Takifugu niphobles (at present Takifugu alboplumbeus) possesses highly concentrated tetrodotoxin (TTX), an extremely potent neurotoxin that provides effective protection from predators, at least at the larval stages. However, the source of the toxin has remained unclear. Recently, DNA from the toxic flatworm Planocera multitentaculata was detected in the intestinal contents of juveniles and young of the pufferfish, suggesting that the flatworm contributes to its toxification at various stages of its life. In this study, we describe the behavior of the pufferfish in the intertidal zone that appears to contribute to its toxification before and during its spawning period: pufferfish were found to aggregate and ingest flatworm egg plates by scraping them off the surface of rocks. DNA analysis based on 28S rRNA and cytochrome c oxidase subunit I (COI) genes identified the egg plates as those of P. multitentaculata. Liquid chromatography with tandem mass spectrometry analysis revealed that the egg plates contain highly concentrated TTX. The feeding behavior of the pufferfish on the flatworm egg plates was also observed in the aquarium. These results suggest that pufferfish feed on the flatworm egg plate, which enables them to acquire toxicity themselves while providing their offspring with the protective shield of TTX.
Collapse
Affiliation(s)
- Taiki Okabe
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa 252-0880, Japan
| | - Hikaru Oyama
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa 252-0880, Japan
| | - Maho Kashitani
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa 252-0880, Japan
| | - Yuta Ishimaru
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa 252-0880, Japan
| | - Rei Suo
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa 252-0880, Japan
| | - Haruo Sugita
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa 252-0880, Japan
| | - Shiro Itoi
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa 252-0880, Japan.
| |
Collapse
|
24
|
Tsutsui S, Suzuki Y, Shibuya K, Nakamura O. Sacciform cells in the epidermis of fugu (Takifugu rubripes) produce and secrete kalliklectin, a novel lectin found in teleosts. FISH & SHELLFISH IMMUNOLOGY 2018; 80:311-318. [PMID: 29902562 DOI: 10.1016/j.fsi.2018.06.017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 06/06/2018] [Accepted: 06/08/2018] [Indexed: 06/08/2023]
Abstract
Kalliklectin is a novel lectin identified in the skin mucus and blood plasma of teleosts, including fugu (Takifugu rubripes). It has been found to exhibit sequence similarity to mammalian plasma kallikrein and coagulation factor XI. The objective of the present study was to clarify the cellular localization of kalliklectin using an antiserum specific to fugu kalliklectin. Immunohistochemical analysis showed that positive reactions were observed in the skin and liver, but not in other tested tissues. Several types of epidermal cells were stained by the antiserum; sacciform cells were one of the types of cells most densely stained by the antiserum in adult fugu skin, whereas mucous cells showed negative staining results. RT-PCR demonstrated that the kalliklectin gene was transcribed in the mucous cell-poor region of adult fugu skin, where sacciform cells were present. These results indicated that epidermal cells, including sacciform cells, produce kalliklectin and secrete it into the mucus.
Collapse
Affiliation(s)
- Shigeyuki Tsutsui
- School of Marine Biosciences, Kitasato University, 1-15-1 Kitasato, Sagamihara, Kanagawa, 252-0373, Japan.
| | - Yuya Suzuki
- School of Marine Biosciences, Kitasato University, 1-15-1 Kitasato, Sagamihara, Kanagawa, 252-0373, Japan
| | - Ko Shibuya
- School of Marine Biosciences, Kitasato University, 1-15-1 Kitasato, Sagamihara, Kanagawa, 252-0373, Japan
| | - Osamu Nakamura
- School of Marine Biosciences, Kitasato University, 1-15-1 Kitasato, Sagamihara, Kanagawa, 252-0373, Japan
| |
Collapse
|
25
|
Itoi S, Ueda H, Yamada R, Takei M, Sato T, Oshikiri S, Wajima Y, Ogata R, Oyama H, Shitto T, Okuhara K, Tsunashima T, Sawayama E, Sugita H. Including planocerid flatworms in the diet effectively toxifies the pufferfish, Takifugu niphobles. Sci Rep 2018; 8:12302. [PMID: 30120305 PMCID: PMC6098040 DOI: 10.1038/s41598-018-30696-z] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 08/04/2018] [Indexed: 11/26/2022] Open
Abstract
Beginning with the larval stages, marine pufferfish such as Takifugu niphobles contain tetrodotoxin (TTX), an extremely potent neurotoxin. Although highly concentrated TTX has been detected in adults and juveniles of these fish, the source of the toxin has remained unclear. Here we show that TTX in the flatworm Planocera multitentaculata contributes to the toxification of the pufferfish throughout the life cycle of the flatworm. A species-specific PCR method was developed for the flatworm, and the specific DNA fragment was detected in the digesta of wild pufferfish adults. Predation experiments showed that flatworm larvae were eaten by the pufferfish juveniles, and that the two-day postprandial TTX content in these pufferfish was 20–50 μg/g. Predation experiments additionally showed flatworm adults were also eaten by pufferfish young, and after two days of feeding, TTX accumulated in the skin, liver and intestine of the pufferfish.
Collapse
Affiliation(s)
- Shiro Itoi
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan.
| | - Hiroyuki Ueda
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Riko Yamada
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Mitsuki Takei
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Tatsunori Sato
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Shotaro Oshikiri
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Yoshiki Wajima
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Ryuya Ogata
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Hikaru Oyama
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Takahiro Shitto
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Kazuya Okuhara
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Tadasuke Tsunashima
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| | - Eitaro Sawayama
- R&D Division, Marua Suisan Co., Ltd. Kamijima, Ehime, 794-2410, Japan
| | - Haruo Sugita
- Department of Marine Science and Resources, Nihon University, Fujisawa, Kanagawa, 252-0880, Japan
| |
Collapse
|
26
|
Biessy L, Smith KF, Boundy MJ, Webb SC, Hawes I, Wood SA. Distribution of Tetrodotoxin in the New Zealand Clam, Paphies australis, Established Using Immunohistochemistry and Liquid Chromatography-Tandem Quadrupole Mass Spectrometry. Toxins (Basel) 2018; 10:E282. [PMID: 29986427 PMCID: PMC6070791 DOI: 10.3390/toxins10070282] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Revised: 06/28/2018] [Accepted: 07/02/2018] [Indexed: 01/28/2023] Open
Abstract
Tetrodotoxin (TTX) is one of the most potent neurotoxins known. It was originally thought to only occur in puffer fish but has now been identified in twelve different classes of freshwater and marine organisms, including bivalves. Despite being one of the world’s most studied biotoxins, its origin remains uncertain. There is contradictory evidence regarding the source of TTX and its pathway through food webs. To date, the distribution of TTX has not been examined in bivalves. In the present study, 48 Paphies australis, a TTX-containing clam species endemic to New Zealand, were collected. Thirty clams were dissected, and organs and tissues pooled into five categories (siphons, digestive gland, adductor muscles, and the ‘rest’) and analyzed for TTX using liquid chromatography-mass spectrometry (LC-MS). The micro-distribution of TTX was visualized in the remaining 18 individuals using an immunohistological technique incorporating a TTX-specific monoclonal antibody. The LC-MS analysis revealed that siphons contained the highest concentrations of TTX (mean 403.8 µg/kg). Immunohistochemistry analysis showed TTX in the outer cells of the siphons, but also in the digestive system, foot, and gill tissue. Observing TTX in organs involved in feeding provides initial evidence to support the hypothesis of an exogenous source in P. australis.
Collapse
Affiliation(s)
- Laura Biessy
- Cawthron Institute, Private Bag 2, Nelson 7010, New Zealand.
- Department of Biological Sciences, University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand.
| | - Kirsty F Smith
- Cawthron Institute, Private Bag 2, Nelson 7010, New Zealand.
| | | | - Stephen C Webb
- Cawthron Institute, Private Bag 2, Nelson 7010, New Zealand.
| | - Ian Hawes
- Department of Biological Sciences, University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand.
| | - Susanna A Wood
- Cawthron Institute, Private Bag 2, Nelson 7010, New Zealand.
| |
Collapse
|