• Korean Journal of Fisheries and Aquatic Sciences
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• v.28 no.3
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• pp.364-372
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• 1995

On the outbreak of paralytic shellfish poisoning in April 1993 in most of shellfish harvesting areas in Jinhae Bay, Korea, to clarify the toxin production of causative organism Alexandrium species, 19 axenic clonal isolates established from the benthic resting cysts in three different stations of those culture grounds were subjected to PSP toxin analysis by HPLC. Individual toxin content per cell was highly variable among the strains isolated from a sampling area and originated from an individual cyst. Average toxin contents in those areas revealed higher values of 54-70 fmol/cell. Toxin profiles included C1/C2(epiGTX8/GTX8), GTX1/GTX4 and neoSTX as the major components, and GTX2/GTX3, GTX5, C4, dcSTX and STX as the minor or sporadic ones. neoSTX on the dominant toxins showed not only most diverse compositional changes comprising $5-54 mol\%$ ranges but also no detection on the half of the strains examined, which were implicated in arising of heterogeneity with a genetic trait within a geographical region. When average toxin composition was compared, carbamate toxins comprised large proportions of $57\%,\;54\%\;and\;67\%$ as total toxin in St. 1, St. 2 and St. 4, respectively. These results suggested that an extensive paralytic shellfish toxification in Jinhae Bay could be largely due to the production of highly potent carbamate toxins in the causative dinoflagellate Alexandrium species.

• Journal of Food Hygiene and Safety
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• v.39 no.5
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• pp.404-411
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• 2024

Paralytic Shellfish Poisoning (PSP) occurs when humans consume shellfish contaminated with saxitoxin (STX) and its derivatives. It causes symptoms ranging from numbness and nausea to severe muscle paralysis and respiratory failure. Toxic equivalency factors (TEFs) are used to standardize the toxic effects of various PSP toxins for risk assessment. Traditional detection methods, such as mouse bioassays, have been used to set the TEFs, but ethical concerns over in vivo studies have shifted the focus toward analytical methods, such as high-performance liquid chromatography. However, in vivo data are essential for establishing TEFs, particularly for emerging marine biotoxins. This study employed a three-level response surface pathway (RSP) design, which reduced the number of animals used to evaluate the median lethal dose (LD₅₀) of STX and its derivatives. The LD₅₀ and TEF values for STX dihydrochloride, neosaxitoxin, decarbamoylsaxitoxin, gonyautoxins 1 & 4 (GTX1&4), GTX2&3, and dcGTX2&3 were 451.3 (1.00), 306.5 (1.47), 860.9 (0.52), 644.5 (0.70), 915.3 (0.49), and 2409.3 (0.19) ㎍/kg, respectively. These TEFs closely aligned with the WHO recommendations and prior oral LD₅₀ values, with Pearson correlation coefficients of 0.969 and 0.994, respectively. This study highlights the need for accurate TEF assignments for PSP toxins and new marine biotoxins, demonstrating that the three-level RSP design balances ethical concerns and provides reliable toxicity data.

• Journal of Environmental Science International
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• v.18 no.12
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• pp.1331-1338
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• 2009

Marine dinoflagellate Alexandrium minutum producing paralytic shellfish toxins is responsible for paralytic shellfish poisoning (PSP). To investigate its temporal distributions in Chinhae Bay where PSP occurs annually, SYBR Green I based A. minutum-specific real-time PCR probe was developed on the LSU rDNA region. Assay specificity and sensitivity were tested against related species, and its specificity was further confirmed by sequencing of field-derived samples. Ten months field survey in 2008 (a total 100 surface water samples) by using the real-time PCR probe showed that A. minutum was detected at very low densities of 1-4 cells $L^{-1}$ in May and June being spring in Chinhae Bay, Korea.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.1
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• pp.49-54
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• 2006

Cultured cells of the toxic Alexandrium tamarense were fed to four mussel species, Mytilus coruscus, M. edulis, M. galloprovincialis and Septifer vulgatus, to examine the interspecies and interlocality differences in the ability to accumulate paralytic shellfish poisoning (PSP) toxins. Toxin content of A. tamarense cells varied during culture period. In contrast, toxin composition in the cell (C1,2, GTX1-4 and neoSTX) was constantly stable. In feeding experiment, the four mussel species collected from Geoje intoxicated after uptake of A. tamarense. Toxin content ($average{\pm}SD\;{\mu}g$ STXeq/100 g) of M. coruscus, M. edulis, M. galloprovincialis and Septifer vulgatus were $1,660{\pm}79,\;3,914{\pm}2,242,\;5,626{\pm}1,620\;and\;958{\pm}163$, respectively. Toxin profiles included C1,2, GTX1,4 and neoSTX as the major components, and dcGTX2,3, GTX2,3, neoSTX and STX as the minor ones. Toxin accumulation of three mussel species collected from Pohang, Geoje and Anmyon-do showed interspecies and interlocality differences. Toxin content ($average{\pm}SD\;{\mu}g$ STXeq/100 g) were $91{\pm}4,\;151{\pm}14,\;39{\pm}3$ in M coruscus, $189{\pm}1,\;231{\pm}11,\;206{\pm}15$ in M edu/is and $214{\pm}28,\;326{\pm}30,\;291{\pm}26$ in M. galloprovincialis in order of Anmyon-do, Geoje and Pohang.

• Journal of Food Hygiene and Safety
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• v.15 no.4
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• pp.287-292
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• 2000

The toxicity and toxin composition between blue mussel, Mytilus edulis and oyster, Crassostrea gigas collected at Woepori in Ko je island in South Coast of Korea in 1996 and 1997 were compared. The highest toxicity score was about 10 times higher in blue mussel than oyster (blue mussel, 8,670 $\mu\textrm{g}$; oyster, 860$\mu\textrm{g}$ in 1996, blue mussel, 5,657 $\mu\textrm{g}$/100g in 1997). The blue mussel also retained its toxicity for slightly longer period than oyster. In the both shellfish, PSP was composed almost exclusively of C toxicity (Cl and C2, 20~65%) and gonyautoxins (GTXl, 2, 3, and 4, 38~78%). In the early period of toxin accumulation, the ratio of 11$\beta$-epimer toxins (C2, GTX4) whose amount was 25~56 mole% (5th March to 12th April in 1996) and 25~80 mole% (18th March to 7th April in 1997), were higher than that of 11-epimer toxins (Cl, GTX2) whose amount was 41~57 mol%(27th May to 3rd June in 1996) and 25~56 mole% (29th April to 12th May in 1997), became higher than that of 11-epimer toxins. The toxin compositions in the both samples changed on a daily basis, presumably owing to metabolism of the toxin in the bivalves.

• Journal of Food Hygiene and Safety
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• v.39 no.5
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• pp.463-466
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• 2024

Marine microalgal biotoxins can accumulate in seafoods, posing significant risk to human health. These toxins include tetrodotoxin (TTX) and can cause paralytic shellfish poisoning (PSP), diarrhetic shellfish poisoning (DSP), and amnesic shellfish poisoning (ASP). With accelerating climate change, the frequency and intensity of harmful algal blooms capable of producing biotoxins have increased. In South Korea, the Ministry of Food and Drug Safety (MFDS) regulates traditional toxins, including TTX and toxins causing PSP, DSP, and ASP. In contrast, the U.S. Food and Drug Administration (FDA) and European Food Safety Authority (EFSA) have established regulatory standards for a broader spectrum of marine biotoxins, including yessotoxins (YTXs), brevetoxins (BTXs), azaspiracids (AZAs), and ciguatoxins (CTXs), to ensure seafood safety. To effectively address this global concern, the MFDS launched an R&D project entitled "Establishment of the Safety Management System for Marine Biotoxins" (2020-2024). This project focused on enhancing analytical methods to detect unregulated toxins, assessing contamination levels, and developing rapid detection techniques. The project proposal emphasizes the need to establish a comprehensive monitoring system to mitigate future risks, particularly as climate change expands the range of toxic marine species. This project aims to advance our understanding of marine biotoxin contamination and strengthen seafood safety measures in South Korea by aligning them with international standards. This special issue compiles knowledge accumulated and technical advancements related to marine biotoxins, stemming from the outcomes of this project. It includes 12 papers describing analyses of various regulated and unregulated marine biotoxins, the current prevalence of seafood contamination, toxicity assessments, rapid analytical methods, and the state of safety management.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.42 no.4
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• pp.366-372
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• 2009

This study looked at toxicity of Mediterranean mussels, Mytilus galloprovincialis, which had accumulated paralytic shellfish toxins (PST) from early March to late May 2005 at Jinhae Bay, Korea. Alexandrium sp. was observed in low densities (< 1,000 cells/L) at the beginning of the study in March, increased rapidly in April, declined rapidly and disappeared in May. Although low densities of Alexandrium sp. were observed in March, mussel toxicity exceeded regulation level ($80{\mu}g$ STXeq. /100 g). Peak PSP (Paralytic Shellfish Poisoning) toxicity in the mussels occurred during high Alexandrium sp. cell densities in April. Mussels toxicity decreased with decline of Alexandrium sp. cell density. Major toxin components identified were $GTX_1$, $GTX_4$, followed by $C_1$, $C_2$, $GTX_2$, $GTX_3$ and neoSTX. Trace or sporadic toxin components were STX, $GTX_5$, $dcGTX_2$, $dcGTX_3$ and dcSTX. Toxin component analysis from the middle to end of the study showed that $11{\beta}$-epimers ($GTX_{3,4}$, $C_2$) were converted into $11{\alpha}$-epimers ($GTX_{1,2}$, $C_1$) and started to determine STX.

• Journal of Food Hygiene and Safety
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• v.33 no.5
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• pp.404-411
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• 2018

To evaluate bacteriological and toxicological safety hygienic indicator bacterium and paralytic and diarrhetic shellfish toxins in the shellfish produced in Hansan Geojeman 2013-2017 were investigated. Fecal coliforms were < 18~330 MPN/100 g in 404 oyster samples. But all samples tested, did not exceed 230 E. coli MPN/100 g. Geometric mean of E. coli for oyster samples collected during major shellfish production period was 24.3 MPN/100 g, considerde stable results. Bacteriological quality of oysters collected from Hansan Geojeman meets the standard value based on shellfish hygiene of the Food Sanitation Act of Korea and also meets Grade A, according to classification of shellfish harvesting areas of the European Union. For toxicological evaluation of Hansan Geojeman, 532 oyster samples and 268 mussel samples as an indicator, were analyzed. Paralytic shellfish toxins were detected in the range of 0.42~2.29 mg/kg in eight mussel samples, and exceeded criteria in three samples from early to late April 2013. Diarrhetic shellfish toxin was detected in three of 120 samples, but it was revealed to be under regulation value (0.16 mg Okadaic Acid equ./kg). As a result of toxicological evaluation, paralytic and diarrhetic shellfish toxins were not detected in oyster samples, but it was found that mussel as an indicator species, exceeded the threshold value of paralytic shellfish toxin. Accordingly, sanitary surveys were continuously requested for food safety management of shellfish.

• Fisheries and Aquatic Sciences
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• v.12 no.3
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• pp.227-235
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• 2009

The marine toxic dinoflagellate Alexandrium catenella has been implicated in numerous paralytic shellfish poisoning (PSP) events in many countries. Due to difficulties in rapidly identifying A. catenella, field-based study of this species has been problematic. The present study developed a TaqMan format A. catenella-specific probe for real-time PCR assay (specific to Korean genotype) based on LSU rDNA sequence information for studying geographic and temporal distribution of the species in surface sediments and water columns of Jinhae Bay, Korea. The field survey from 2007 to 2008 revealed that A. catenella occurred in most seasons at low densities, mostly below 1 cell $mL^{-1}$, and was more abundant in spring (maximum cell density of 2 cells $mL^{-1}$) when shellfish exceed the quarantine toxin level for PSP toxins in Jinhae Bay.

• Fisheries and Aquatic Sciences
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• v.24 no.11
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• pp.360-369
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• 2021

Paralytic shellfish toxins (PSTs) and tetrodotoxin (TTX) are neurotoxins that display pharmacological activity that is similar to that of specific sodium channel blockers; they are the principle toxins involved in shellfish and puffer fish poisoning. In Korea, puffer fish is a very popular seafood, and several cases of accidental poisoning by TTX have been reported. Therefore, it is necessary to determine whether puffer fish poisoning incidents are caused by PSTs or by TTX. In this study, we used mouse bioassay (MBA) and liquid chromatograph-tandem mass spectrometry (LC-MS/MS) to determine the presence of PSTs and TTX in puffer fish from an area near Mireuk-do, Tong-Yeong on the southern coast of Korea from January through March, 2014. The toxicity of PSTs and TTX extracts prepared from three organs of each specimen was analyzed by MBA. Most of the extracts killed mice with typical signs of TTX and PSTs. The LC-MS/MS analysis of seven specimens of Takifugu pardalis and Takifugu niphobles, each divided into muscles, intestines, and liver, were examined for TTX. In T. pardalis, the TTX levels were within the range of 1.3-1.6 ㎍/g in the muscles, 18.8-49.8 ㎍/g in the intestines, and 23.3-96.8 ㎍/g in the liver. In T. niphobles, the TTX levels were within the range of 2.0-4.5 ㎍/g in the muscles, 23.9-71.5 ㎍/g in the intestines, and 28.1-114.8 ㎍/g in the liver. Additionally, the toxicity profile of the detected PSTs revealed that dcGTX3 was the major component in T. pardalis and T. niphobles. When PSTs were calculated as saxitoxin equivalents the levels were all less than 0.5 ㎍/g, which is below the permitted maximum standard of 0.8 ㎍/g. These findings indicate that the toxicity of T. pardalis and T. niphobles from the southern coast of Korea is due mainly to TTX and that PSTs do not exert an effect.