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Amano M, Amiya N, Otsuka Y, Homma J, Hagio H, Takatani T, Yamamoto N, Yamaguchi K, Sakakura Y. Distribution of pufferfish saxitoxin- and tetrodotoxin-binding protein homolog and tetrodotoxin in the brain and pituitary of juvenile tiger puffer Takifugu rubripes. Toxicon 2024; 246:107777. [PMID: 38810888 DOI: 10.1016/j.toxicon.2024.107777] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 05/14/2024] [Accepted: 05/26/2024] [Indexed: 05/31/2024]
Abstract
Pufferfish saxitoxin- and tetrodotoxin (TTX)-binding protein (PSTBP) is considered to transfer TTX between tissues. The immunohistochemical distribution of PSTBP-homolog (PSTBPh) and TTX in the brain and pituitary of hatchery-reared juvenile tiger puffer Takifugu rubripes was investigated. PSTBPh was observed mainly in the pars intermedia of the pituitary. TTX was only detected in a TTX-fed fish in the neurohypophysis of the pituitary and in several other brain regions. The relationship between PSTBPh and TTX is discussed.
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Affiliation(s)
- Masafumi Amano
- School of Marine Biosciences, Kitasato University, Sagamihara, Kanagawa, 252-0373, Japan.
| | - Noriko Amiya
- School of Marine Biosciences, Kitasato University, Sagamihara, Kanagawa, 252-0373, Japan
| | - Yuma Otsuka
- School of Marine Biosciences, Kitasato University, Sagamihara, Kanagawa, 252-0373, Japan
| | - Junnosuke Homma
- School of Marine Biosciences, Kitasato University, Sagamihara, Kanagawa, 252-0373, Japan
| | - Hanako Hagio
- Laboratory of Fish Biology, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi, 464-8601, Japan; Institute for Advanced Research, Nagoya University, Nagoya, Aichi, 464-8601, Japan
| | - Tomohiro Takatani
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Nagasaki, 852-8521, Japan
| | - Naoyuki Yamamoto
- Laboratory of Fish Biology, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi, 464-8601, Japan
| | - Kenichi Yamaguchi
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Nagasaki, 852-8521, Japan
| | - Yoshitaka Sakakura
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Nagasaki, 852-8521, Japan
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2
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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.
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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.
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Anastasiou TI, Kagiampaki E, Kondylatos G, Tselepides A, Peristeraki P, Mandalakis M. Assessing the Toxicity of Lagocephalus sceleratus Pufferfish from the Southeastern Aegean Sea and the Relationship of Tetrodotoxin with Gonadal Hormones. Mar Drugs 2023; 21:520. [PMID: 37888455 PMCID: PMC10608560 DOI: 10.3390/md21100520] [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: 09/03/2023] [Revised: 09/26/2023] [Accepted: 09/27/2023] [Indexed: 10/28/2023] Open
Abstract
Given the dramatic increase in the L. sceleratus population in the southeastern Aegean Sea, there is growing interest in assessing the toxicity of this pufferfish and the factors controlling its tetrodotoxin (TTX) content. In the present study, liver, gonads, muscle and skin of 37 L. sceleratus specimens collected during May and June 2021 from the island of Rhodes, Greece, were subjected to multi-analyte profiling using liquid chromatography-tandem mass spectrometry (LC-MS/MS) in order to quantitate TTX and evaluate whether this biotoxin interrelates with hormones. TTX and its analogues 4-epiTTX, 11-deoxyTTX, 11-norTTX-6-ol, 4,9-anhydroTTX and 5,11/6,11-dideoxyTTX were detected in all tissue types. Liver and gonads were the most toxic tissues, with the highest TTX concentrations being observed in the ovaries of female specimens. Only 22% of the analyzed muscle samples were non-toxic according to the Japanese toxicity threshold (2.2 μg TTX eq g-1), confirming the high poisoning risk from the inadvertent consumption of this species. Four steroid hormones (i.e., cortisol, testosterone, androstenedione and β-estradiol) and the gonadotropin-releasing hormone (GnRH) were detected in the gonads. Androstenedione dominated in female specimens, while GnRH was more abundant in males. A positive correlation of TTX and its analogues with β-estradiol was observed. However, a model incorporating sex rather than β-estradiol as the independent variable proven to be more efficient in predicting TTX concentration, implying that other sex-related characteristics are more important than specific hormone-regulated processes.
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Affiliation(s)
- Thekla I Anastasiou
- Hellenic Centre for Marine Research (HCMR), Institute of Marine Biology, Biotechnology and Aquaculture, 71500 Heraklion, Greece
- Department of Biology, University of Crete, 70013 Heraklion, Greece
| | - Eirini Kagiampaki
- Hellenic Centre for Marine Research (HCMR), Institute of Marine Biology, Biotechnology and Aquaculture, 71500 Heraklion, Greece
| | - Gerasimos Kondylatos
- Hellenic Centre for Marine Research (HCMR), Hydrobiological Station of Rhodes, 85131 Rhodes, Greece
| | | | - Panagiota Peristeraki
- Hellenic Centre for Marine Research (HCMR), Institute of Marine Biological Resources and Inland Waters, 71500 Heraklion, Greece
| | - Manolis Mandalakis
- Hellenic Centre for Marine Research (HCMR), Institute of Marine Biology, Biotechnology and Aquaculture, 71500 Heraklion, Greece
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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.
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Affiliation(s)
- Yoshimi Ogino
- Graduate School of Fisheries and Environmental SciencesNagasaki UniversityNagasakiJapan
| | - Atsuko Yamaguchi
- Graduate School of Fisheries and Environmental SciencesNagasaki UniversityNagasakiJapan
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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.
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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
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Amano M, Takatani T, Sakayauchi F, Oi R, Sakakura Y. The brain of the wild toxic marine pufferfishes accumulates tetrodotoxin. Toxicon 2022; 218:1-7. [PMID: 36041513 DOI: 10.1016/j.toxicon.2022.08.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2022] [Revised: 08/06/2022] [Accepted: 08/21/2022] [Indexed: 10/15/2022]
Abstract
We have previously detected tetrodotoxin (TTX) in the brain of the wild toxic torafugu Takifugu rubripes by immunohistochemistry and LC/MS analysis. We have also indicated that TTX is a stress-relieving substance in the brain and reduces agonistic interactions in torafugu juveniles. Although the toxicity of marine pufferfish in the Japanese waters has been extensively examined for food hygiene, whether wild toxic pufferfish generally possess TTX in the brain has not been investigated. In the present study, we examined the presence of TTX in the brain of several wild toxic marine pufferfishes such as kusafugu T. alboplumbeus, komonfugu T. poecilonotus, shosaifugu T. snyderi, okinawafugu Chelonodon patoca, and in wild non-toxic pufferfishes such as shirosabafugu Lagocephalus spadiceus and yoritofugu Sphoeroides pachygaster. We also examined tsumugihaze Yongeichthys criniger, known to possess TTX in the skin, viscera, and gonad. TTX was extracted from the brain, liver, skin, and muscle and was analyzed by LC/MS. TTX was detected in the brain as well as in the liver, skin, and muscle in kusafugu, komonfugu, shosaifugu, okinawafugu, and tsumugihaze. In shirosabafugu, low level of TTX (0.8 mouse unit/g-brain) was detected in the brain in 1 out of 3 individuals. In yoritofugu, no TTX was detected in any of the tissues. We conclude that the brain is also an organ that contains TTX in the wild toxic marine pufferfishes.
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Affiliation(s)
- Masafumi Amano
- School of Marine Biosciences, Kitasato University, Sagamihara, Kanagawa, 252-0373, Japan.
| | - Tomohiro Takatani
- Graduate School of Fisheries and Environmental Sciences, Institute of Integrated Science and Technology, Nagasaki University, Nagasaki, 852-8521, Japan
| | - Fuka Sakayauchi
- School of Marine Biosciences, Kitasato University, Sagamihara, Kanagawa, 252-0373, Japan
| | - Ryohei Oi
- School of Marine Biosciences, Kitasato University, Sagamihara, Kanagawa, 252-0373, Japan
| | - Yoshitaka Sakakura
- Graduate School of Fisheries and Environmental Sciences, Institute of Integrated Science and Technology, Nagasaki University, Nagasaki, 852-8521, Japan
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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.
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Amano M, Amiya N, Fukushima K, Hagio H, Yamamoto N, Sakakura Y. Effects of crowding stress on the hypothalamo-pituitary-interrenal axis of the self-fertilizing fish, Kryptolebias marmoratus. Comp Biochem Physiol A Mol Integr Physiol 2021; 264:111110. [PMID: 34737084 DOI: 10.1016/j.cbpa.2021.111110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 10/29/2021] [Accepted: 10/29/2021] [Indexed: 11/26/2022]
Abstract
We tested whether crowding stress affects the hypothalamo-pituitary-interrenal (HPI) axis of the self-fertilizing fish, Kryptolebias marmoratus, which is known to be aggressive in the laboratory conditions but sometimes found as a group from a single land crab burrow in the wild. The projection of corticotropin-releasing hormone (CRH) neurons to the adrenocorticotropic hormone (ACTH) cells in the pituitary was confirmed by dual-label immunohistochemistry; CRH-immunoreactive (ir) fibers originating from cell bodies located in the lateral tuberal nucleus (NLT) of the hypothalamus were observed to project to ACTH-ir cells in the rostral pars distalis of the pituitary. Then, fish were reared solitary or in pairs for 14 days, and the number of CRH-ir cell bodies in the NLT of the hypothalamus and cortisol levels in the body without head region were compared. The number of CRH-ir cell bodies and cortisol levels were significantly higher in paired fish. These results indicate that crowding stress affects the HPI axis in K. marmoratus which thrive in small burrows with limited water volume.
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Affiliation(s)
- Masafumi Amano
- School of Marine Biosciences, Kitasato University, Sagamihara, Kanagawa 252-0373, Japan.
| | - Noriko Amiya
- School of Marine Biosciences, Kitasato University, Sagamihara, Kanagawa 252-0373, Japan
| | - Keisuke Fukushima
- School of Marine Biosciences, Kitasato University, Sagamihara, Kanagawa 252-0373, Japan
| | - Hanako Hagio
- Institute for Advanced Research, Nagoya University, Nagoya, Aichi 464-8601, Japan; Laboratory of Fish Biology, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan
| | - Naoyuki Yamamoto
- Laboratory of Fish Biology, Graduate School of Bioagricultural Sciences, Nagoya University, Nagoya, Aichi 464-8601, Japan
| | - Yoshitaka Sakakura
- Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Nagasaki 852-8521, Japan
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Ulman A, Yildiz T, Demirel N, Canak O, Yemişken E, Pauly D. The biology and ecology of the invasive silver-cheeked toadfish (Lagocephalus sceleratus), with emphasis on the Eastern Mediterranean. NEOBIOTA 2021. [DOI: 10.3897/neobiota.68.71767] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Invasive species pose threats to either human health or inflict ecological and/or economic damage. The silver-cheeked toadfish (Lagocephalus sceleratus), a Lessepsian species, is one of the most harmful species in the Mediterranean Sea, because of its potent neurotoxin, impacts on marine biodiversity, and the increased costs and labor they inflict on fishers. Since the catch and consumption of this pufferfish is prohibited by almost all countries bordering the Mediterranean, they have now expanded into the entire Mediterranean and Black Sea. We performed a comprehensive study of L. sceleratus covering ecological aspects, growth, reproduction, diet and trophic level based on samples from southwestern coasts of Turkey. The estimated growth parameters were L∞ = 88.7 cm, K = 0.27 year-1, C = 0.6 and WP = 0.1. Their sex-ratio was M/F = 1:0.69. Lagocephalus sceleratus appears to be a batch spawner with discontinuous oocyte recruitment and has different spawning seasons in the Eastern Mediterranean which seem to be based on temperature cues which get shorter in duration as one moves north from the Suez. We also report their first positive ecological trait, that they are controlling some other invasive species through their diets, such as lionfish, Red Sea goatfish, rabbitfish and longspine sea urchins, in addition to controlling themselves through cannibalism, which appears to be density-dependent. They are indeed a top predator in the region with a trophic level of 4.1. We suggest that targeted fishing using improved gear-types to reduce fishing gear damages are initiated, and that finding commercial markets for pufferfish could help to naturally fund ongoing control efforts.
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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.
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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
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