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Percent reactivity of paralytic shellfish toxins (PSTs) quantified by receptor binding assay (RBA) and enzyme-linked immunosorbent assay (ELISA). Percent reactivity for saxitoxin (STX) is 100 % by definition (μg STX equiv./L) for both assays. * Indicate the standards that were analyzed at three concentrations in order to determine the standard deviation of the RBA (assay sd = 1.7 %). Reactivity data for ELISA is from Abraxis LLC, Warminster, PA.
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Traditionally, harmful algal bloom studies have primarily focused on quantifying toxin levels contained within the phytoplankton cells of interest. In the case of paralytic shellfish poisoning toxins (PSTs), intracellular toxin levels and the effects of dietary consumption of toxic cells by planktivores have been well documented. However, little in...
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Context 1
... Abraxis ELISA microtiter plate kit recognizes STX and other PSTs at varying degrees. Cross-reactivities for the ELISA are < 0.2 % for GTX1,4, 1.3 % for NEO, 23 % for GTX2,3 and 100 % for STX ( Figure 5). Due to the selectivity of the ELISA, the toxin profile can profoundly affect intracellular STX and extracellular STX levels quantified by the assay. ...Context 2
... to the selectivity of the ELISA, the toxin profile can profoundly affect intracellular STX and extracellular STX levels quantified by the assay. Further analysis of a set of PST standards by receptor binding assay (RBA) in the present study revealed cross-reactivities of 100% (STX), 148 %(NEO), 31% (dcSTX), 27 ± 2.3% (GTX1,4), 18 ± 1.5% (GTX2,3), 6.7 ± 1.2% (dcGTX2,3), 1.7% (dcNEO), 1.2% (B1), and 0.4% (C1,2) ( Figure 5). Saxitoxin has 100% cross-reactivity by definition because STX is the standard for both ELISA and RBA assays. ...Context 3
... RBA values were 33 ± 25 and 7.4 ± 1.8 times higher than ELISA values for intracellular and extracellular STX, respectively. This is likely explained by the fact that % cross- reactivities for GTX1,4 (the most abundant toxin in Sequim Bay isolates) were < 0.2 and 27 ± 2.3 for ELISA (Abraxis LLC, Warminster, PA) and RBA (this study), respectively ( Figure 5). . Percent reactivity of paralytic shellfish toxins (PSTs) quantified by receptor binding assay (RBA) and enzyme-linked immunosorbent assay (ELISA). ...Context 4
... is due to the selectivity of the assays as well as the composition of the toxin profiles in the samples. For example, GTX1,4, the most abundant toxin in the Sequim Bay isolates (Figure 4), had drastically different cross-reactivities of 27 ± 2.3 and < 0.2 % when quantified via RBA and ELISA, respectively ( Figure 5). Not surprisingly, RBA consistently gave higher values than ELISA for both intra-and extracellular STX in our comparisons (Table 3). ...Similar publications
Harmful algal blooms (HAB), and the consequent release of toxic metabolites, can be responsible for seafood poisoning outbreaks. Marine wildlife can accumulate these toxins throughout the food chain, which presents a threat to consumers’ health. Some of these toxins, such as saxitoxin (STX), domoic acid (DA), ciguatoxin (CTX), brevetoxin (BTX), tet...
Phytoplankton is the basis of the food web including various taxonomic groups. Under appropriate conditions these microorganisms are able to proliferate and cause harmful algal blooms (HAB). The HAB can be toxic depending on the organisms that caused it, if they are capable of producing toxins, or harmful if its densities cause many adverse conditi...
The presence of neurotoxic species within the genus Alexandrium along the U.S. coastline has raised concern of potential poisoning through the consumption of contaminated seafood. Paralytic
shellfish toxins (PSTs) detected in shellfish provide evidence that these harmful events have increased in frequency and severity
along the California coast dur...
Citations
... It has often been assumed that Paralytic Shellfish Toxins (PST) remain within dinoflagellate cells until they are digested, but this may be a consequence of difficulty measuring PST in salt water because salt interferes with the analysis. Lefebvre et al. (2008) measured the extracellular toxin levels in both field samples during Alexandrium blooms and in laboratory Alexandrium cultures by receptor binding assay (RBA) and enzyme-linked immunosorbent assay (ELISA). They showed that extracellular PST were present during blooms and in culture media. ...
... Although there is no report on the global HAB incidence and problems in shrimp farms, according to the analysis of Mann [3] in shrimp cultures in Australia, episodes of significant stock losses on farms were potentially misdiagnosed and attributed to other causes, particularly diseases, when in fact disease was a secondary consequence to HAB blooms [3]. The presence of dissolved metabolites (DM) in the aquatic environment, such as those produced by HAB could also contribute to misdiagnose since, as the in case of PST and bioactive extracellular compounds [7], they are challenging to extract from the aqueous medium [8]. This problematic could be ubiquitous in many countries. ...
... The effect of dissolved metabolites (DMs) of G. catenatum, in experimental conditions, on juveniles of the white shrimp L. vannamei, one of the main fisheries and main marine cultures in many countries [6] was tested, to our best knowledge, for the first time. The experiment simulated the presence of environmental G. catenatum cell concentrations that seem to be ubiquitous when HABs occur [8], particularly in the Pacific Mexican coast [16,17,27]. Results clearly show that DMs, including PST, from this dinoflagellate are uptaken, incorporated in tissues, and induced important behavioral changes and tissues damages even at the lowest concentration of DM (10 4 treatment). ...
Harmful algae blooms (HABs) are a conspicuous phenomenon that affect the coastal zone worldwide. Aquaculture industry zones are not excluded from being affected by HAB that cause organism mortality and jeopardize their innocuity due to the contamination by phytotoxins with the concomitant economic losses. Direct ingestion of metabolites from HAB species or organisms contaminated with phycotoxins together with dermal absorption of dissolved metabolites (DM), including toxins, are the two main routes of poisoning. From these poisoning routes, the effect of DM, particularly paralytic shellfish toxins (PST), has been relatively understudied. This intoxication route can be conspicuous and could be involved in many significant mortalities of cultivated marine organisms. In this study, white shrimp juveniles (2.1 g wet weight) of Litopenaeus vannamei were exposed to extracts of 104, 105 and 106 cells/L of the dinoflagellate Gymnodinium catenatum, a PST producer. The experiment ended after 17 h of exposure when shrimps exposed to 106 cells/L extract started to die and the rest of the shrimps, from this and other treatments, did not respond to gentle physical stimulus and their swimming activity was low and erratic. Toxin concentrations were determined using high performance liquid chromatography while qualitative and quantitative histological damages were assessed on the tissues. In general, most toxins were accumulated in the hepatopancreas where more than 90% were found. Other tissues such as intestine, muscle, and gills contained less than 10% of toxins. Compared to the control, the main significative tissue damages were, loss of up to 80% of the nerve cord, 40% of the muscle coverage area, and reduction of the gill lamella width. Also, atrophy in hepatopancreas was observed, manifested by a decrease in the height of B cells, lumen degeneration and thinning of tubules. Some damages were more evident when shrimps were exposed to higher concentrated extracts of G. catenatum, however, not all damages were progressive and proportional to the extract concentration. These data confirm that PST dissolved enter the shrimp, possibly via the gills, and suggest that dissolved metabolites, including PST, may cause tissue damage. Other dissolved metabolites produced by G. catenatum, alone or in synergy, may also be involved. These results also pointed out the importance of dissolved molecules produced for this dinoflagellate and the potential effect on cultured shrimp.
... PSTs are a group of neurotoxic toxins produced dinoflagellates of the genus Alexandrium, Gymnodinium, and Pyrodinium that accumulate in seafood and can induce PSP in humans [93][94][95]. PSP symptoms include ataxia, respiratory depression or failure, tachycardia, and heart paralysis [96,97]. There is no treatment for this poisoning identified more than 30 analogs related to PSP [98]. ...
A significant spread and prevalence of algal toxins and, in particular, marine biotoxins have been observed worldwide over the last decades. Marine biotoxins are natural contaminants produced during harmful algal blooms being accumulated in seafood, thus representing a threat to human health. Significant progress has been made in the last few years in the development of analytical methods able to evaluate and characterize the different toxic analogs involved in the contamination, Liquid Chromatography coupled to different detection modes, including Mass Spectrometry, the method of choice due to its potential for separation, identification, quantitation and even confirmation of the different above-mentioned analogs. Despite this, the risk characterization in humans is still limited, due to several reasons, including the lack of reference materials or even the limited access to biological samples from humans intoxicated during these toxic events and episodes, which hampered the advances in the evaluation of the metabolites responsible for the toxicity in humans. Mass Spectrometry has been proven to be a very powerful tool for confirmation, and in fact, it is playing an important role in the characterization of the new biotoxins analogs. The toxin metabolization in humans is still uncertain in most cases and needs further research in which the implementation of Mass Spectrometric methods is critical. This review is focused on compiling the most relevant information available regarding the metabolization of several marine biotoxins groups, which were identified using Mass Spectrometry after the in vitro exposition of these toxins to liver microsomes and hepatocytes. Information about the presence of metabolites in human samples, such as human urine after intoxication, which could also be used as potential biomarkers for diagnostic purposes, is also presented.
... Such method is complicated and time-consuming, and cannot provide an early warning of the contamination risk from algal toxins in the shellfi sh and aquatic environment. During survival and competition, toxinproducing algae often secrete toxins out of the cell, and monitoring of extracellular toxins in seawater is more effi cient and faster (Lefebvre et al., 2008;Pan et al., 2017). In addition, the seawater is an important medium for the survival of marine organisms. ...
Lipophilic marine algal toxins (LMATs) are produced by some toxigenic microalgae, which pose a serious threat to marine ecosystem and even human health. The occurrence and environmental control factors of LMATs in the surface seawater and phytoplankton in spring in Laizhou Bay in which Huanghe (Yellow) River estuary is included, in Shandong, East China were investigated. Okadaic acid (OA), pectenotoxin-2 (PTX2), dinophysistoxin-1 (DTX1), pectenotoxin-2 seco acid (PTX2 SA), DTX2, 7-epi-PTX2 SA, PTX11, and 13-desmethyl spirolide C (SPX1) were detected from the surface seawater samples, and PTX2, 7-epi-PTX2 SA, OA, DTX2, DTX1, PTX2 SA, and PTX11 were discovered in the phytoplankton samples showed a decreasing trend. The concentrations of XLMATs in the seawater and phytoplankton ranged 2.03–74.38 ng/L on average of 13.72 ng/L and 0.98–479.27 pg/L on average of 50.20 pg/L, respectively. The joint influence of terrigenous input and internal circulation could promote the growth, toxin production, and toxin release of toxin-producing algae, leading to a higher content of LMATs in the bay nearby the Huanghe River estuary in both seawater and phytoplankton. The concentration of LMATs in spring was higher than that in summer, showing obvious seasonal variation. In addition, no significant correlation between most of the physiochemical parameters and LMAT contents in seawater was revealed by correlation analysis except for the positive correlation between DTX2 and chlorophyll a, OA and NH4−N. However, the increase of dissolved inorganic nitrogen content in seawater could enhance the production of OA, DTX1, and DTX2 in phytoplankton due probably to that the inorganic N input could benefit the growth and stimulate toxin production of toxin-producing algae. The result also proved that some PTX2 may be originated from Procentrum spp. and OA, DTXs and part of PTX2 may be originated from Dinophysis spp.
... Among the algal toxins, paralytic shellfish toxins (PST) are among the most hazardous biotoxins due to their severe toxicity and wide distribution. They are mainly produced by eukaryotic dinoflagellates and prokaryotic cyanobacteria (Hummert et al. 1997;Lefebvre et al. 2008;Usup et al. 2012). Recently, six cases of human poisoning occurred in Qinhuangdao, China, due to the consumption of seafood containing PST during blooms in 2019. ...
The chain-forming dinoflagellate Gymnodinium catenatum is the only known gymnodinioid dinoflagellate that produces paralytic shellfish toxins (PST). Dense blooms caused by the dinoflagellate have been frequently reported in coastal waters of Fujian, China since 2017. While there is still limited understanding of the major physiological characteristics of G. catenatum isolated from Fujian coastal waters, the growth and toxin production of the G. catenatum strain were examined in batch cultures with different levels of irradiance, temperature, salinity, nitrate, and phosphate conditions. The results indicated that the highest maximum cell density of the strain was achieved at 70 µmol m⁻² s⁻¹, with the highest growth rate at 120 µmol m⁻² s⁻¹. The strain grew well within the temperature range of 15–30 °C, with maximum growth rate and cell density achieved at 20 °C. The dinoflagellate also showed higher tolerance to salinity variation (20–40), with the highest growth rate at salinity 25. Meanwhile, G. catenatum showed higher demand for nitrogen and phosphorus as indicated by its higher half-saturation constant. A decrease in nitrate and phosphate greatly inhibited the growth of G. catenatum. The toxin profile of the G. catenatum strain was conservative and dominated mainly by the N-sulfcarbamoyl C-toxins (> 95%), indicating its hypotoxicity. The cellular toxicity increased with the algal growth, with the highest cellular toxicity observed at the stationary growth phase. The cellular toxicity of G. catenatum also responded to environmental variations including lower temperature (15 °C), lower salinity (20), nitrate-repletion, and phosphate-depletion conditions which enhanced the cellular toxicity, while irradiance exerted non-significant influence. The present study depicted the physiological characteristics of the particular G. catenatum strain and provided valuable insight on the ecophysiology of G. catenatum in natural coastal waters.
... Aquatic organisms can simultaneously accumulate the potent biotoxins produced by A. catenella and extracellular toxins released by toxic algae into the water through filter feeding (Botelho et al., 2020;Lefebvre, 2008). In the present study, the toxin profile of A. catenella included GTX1/4 (87%) and GTX2/3 (13%). ...
In the last 5 years, paralytic shellfish toxins (PSTs) have been recurrently detected in mollusks farmed in the mussel culture area of Qinhuangdao city, along with the occurrence of toxic outbreaks linked to dinoflagellate species of the Alexandrium genus. To understand the formation mechanism and variation of these events, continuous and comprehensive PSTs monitoring was carried out between 2017 and 2020. Through the analysis of both phytoplankton and cysts via light microscopy and quantitative polymerase chain reaction, it was shown that Alexandrium catenella was responsible for the production of PSTs, which consisted mainly of gonyautoxins 1,4 (GTX1/4, 87%) and GTX2/3 (13%). During bloom events in 2019, mussels accumulated the highest PSTs value (929 μg STX di-HCl eq·kg⁻¹) in conjunction with the peak of cell abundances, and toxin profiles were consistent with high distributions of GTX1/4, GTX2/3, and Neosaxitoxin. Toxin metabolites vary in different substances and mainly transferred to a stable proportion of α-epimer: β-epimers 3:1. The environmental drivers of Alexandrium blooms included the continuous rise of water temperature (>4 °C) and calm weather with low wind speed and no significant precipitation. By comparing toxin profiles and method sensitivity, it was found that dissolved toxins in seawater are more useful for early warning. These results have important implications for the effective monitoring and management of paralytic shellfish poisoning outbreaks.
... For example, their mutualistic relationships with reef-building corals form the basis of a highly diverse and productive ecosystem. Many dinoflagellates are well-known producers of toxins that can be harmful to humans via syndromes like paralytic shellfish poisoning (PSP) [7][8][9][10][11], neurotoxic shellfish poisoning (NSP) [12][13][14], azaspiracid shellfish poisoning (AZP) [15,16], Diarrheic shellfish poisoning (DSP) [17] and ciguatera fish poisoning (CFP) [18,19]. These metabolites are generally detected because of their bioaccumulation through the marine food-chain into marine organisms including fish, crustaceans and mollusks, which are consumed by humans. ...
... The structures of these metabolites are very similar. In fact, compounds (8)(9) are constituted by a hydroxyl function at position 6 which is replaced by a ketone function in compounds (6)(7). Substituents on C 4 introduce also a structural diversity: (6) and (8) have a hydroxyl group in this position while (7) and (9) have a ribofuranosyl fragment [25]. ...
... The strain TIO523 grew well in the temperature range of 10-30°C, attaining maximum growth rate at 20°C. Its optimal salinity range (25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35) was similar to the Australian (23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34) and Japanese (20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32) (Oshima et al. 1993), there was still noticeable difference in the detailed toxin components of particular dino agellates. The present G. catenatum strain (TIO523) produced trace GTX toxins, while the strain (MEL11) isolated from the same region had a high content of GTX5/6 (Lin et al. 2022). ...
... The strain TIO523 grew well in the temperature range of 10-30°C, attaining maximum growth rate at 20°C. Its optimal salinity range (25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35) was similar to the Australian (23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34) and Japanese (20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32) (Oshima et al. 1993), there was still noticeable difference in the detailed toxin components of particular dino agellates. The present G. catenatum strain (TIO523) produced trace GTX toxins, while the strain (MEL11) isolated from the same region had a high content of GTX5/6 (Lin et al. 2022). ...
... The strain TIO523 grew well in the temperature range of 10-30°C, attaining maximum growth rate at 20°C. Its optimal salinity range (25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35) was similar to the Australian (23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34) and Japanese (20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32) (Oshima et al. 1993), there was still noticeable difference in the detailed toxin components of particular dino agellates. The present G. catenatum strain (TIO523) produced trace GTX toxins, while the strain (MEL11) isolated from the same region had a high content of GTX5/6 (Lin et al. 2022). ...
The chain-forming dinoflagellate Gymnodinium catenatum is the only known gymnodinioid dinoflagellate that produces paralytic shellfish toxins (PST). Dense blooms caused by the dinoflagellate have been frequently reported in coastal waters of Fujian, China since 2017. While there is still limited understanding of the major physiological characteristics of G. catenatum isolated from Fujian coastal waters, the growth and toxin production of the G. catenatum strain were examined in batch cultures with different levels of irradiance, temperature, salinity, nitrate, and phosphate conditions. The results indicated that the highest maximum cell density of the strain was achieved at 70 µmol m − 2 s − 1 , with the highest growth rate at 120 µmol m − 2 s − 1 . The strain grew well within the temperature range of 15–30°C, with maximum growth rate and cell density achieved at 20°C. The dinoflagellate also showed higher tolerance to salinity variation (20–40), with the highest growth rate at salinity 25. Meanwhile, G. catenatum showed higher demand for nitrogen and phosphorus as indicated by its higher half saturation constant. Decrease in nitrate and phosphate greatly inhibited the growth of G. catenatum. The toxin profile of the G. catenatum strain was conservative and dominated mainly by the N-sulfcarbamoyl C-toxins (> 95%), indicating its hypotoxicity. The cellular toxicity increased with the algal growth, with the highest cellular toxicity observed at the stationary growth phase. The cellular toxicity of G. catenatum also responded to environmental variations including lower temperature (15°C), lower salinity (20), nitrate-repletion, and phosphate-depletion conditions which enhanced the cellular toxicity, while irradiance exerted non-significant influence. The present study depicted the physiological characteristics of the particular G. catenatum strain and provided valuable insight on the ecophysiology of G. catenatum in natural coastal waters.
... The extracellular STX levels in the culture media of Alexandrium spp. isolates from Sequim Bay ranged from 12 to 31 μg STX eq L − 1 , as determined by the receptor binding assay (Lefebvre et al., 2008). The study also demonstrated that field-collected seawater contained STX levels of up to 0.8 μg STX eq L − 1 , thus confirming that extracellular PSTs associated with toxic blooms of Alexandrium spp. ...
Ocean acidification caused by increasing emission of carbon dioxide (CO2) is expected to have profound impacts on marine ecological processes, including the formation and evolution of harmful algal blooms (HABs). We designed a set of experiments in the laboratory to examine the effects of increasing CO2 on the growth and toxicity of a toxic dinoflagellate Alexandrium minutum producing paralytic shellfish toxins (PSTs). It was found that high levels of CO2 (800 and 1,200 ppm) significantly promoted the growth of A. minutum compared to the group (400 ppm) representing the current CO2 level. The total yields of PSTs by A. minutum, including both intracellular and extracellular toxins, were significantly enhanced, probably due to the induction of core enzyme activity and key amino acids synthesis for PST production. More interestingly, high level of CO2 promoted the transformation from gonyautoxin2&3 to gonyautoxin1&4 and depressed the release of PSTs from inside to outside of the cells. All these processes collectively led to an apparent increase of A. minutum toxicity. Our study demonstrated that rising CO2 would increase the risk of toxic A. minutum based on the comprehensive analyses of different processes including algal growth and toxin synthesis, transformation and release.
... Although PST is 291 mainly intracellular in dinoflagellates, low levels of extracellular PST have been measured in 292 the culture media of some Alexandrium spp. isolates (Lefebvre et al., 2008). Extracellular PST 293 might have been present in the PST strain culture media and could be involved in the toxic 294 effects observed. ...
Dinoflagellates from the globally distributed genus Alexandrium are known to produce both paralytic shellfish toxins (PST) and uncharacterized bioactive extracellular compounds (BEC) with allelopathic, ichthyotoxic, hemolytic and cytotoxic activities. In France, blooms of Alexandrium minutum appear generally during the spawning period of most bivalves. These blooms could therefore alter gametes and/or larval development of bivalves, causing severe issues for ecologically and economically important species, such as the Pacific oyster Crassostrea (=Magallana) gigas. The aim of this work was to test the effects of three strains of A. minutum producing either only PST, only BEC, or both PST and BEC upon oyster gametes, and potential consequences on fertilization success. Oocytes and spermatozoa were exposed in vitro for 2 h to a range of environmentally realistic A. minutum concentrations (10-2.5 × 104 cells mL-1). Following exposure, gamete viability and reactive oxygen species (ROS) production were assessed by flow cytometry, spermatozoa motility and fertilization capacities of both spermatozoa and oocytes were analysed by microscopy. Viability and fertilization capacity of spermatozoa and oocytes were drastically reduced following exposure to 2.5 × 104 cells mL-1 of A. minutum. The BEC-producing strain was the most potent strain decreasing spermatozoa motility, increasing ROS production of oocytes, and decreasing fertilization, from the concentration of 2.5 × 103 cells mL-1. This study highlights the significant cellular toxicity of the BEC produced by A. minutum on oyster gametes. Physical contact between gametes and motile thecate A. minutum cells may also contribute to alter oyster gamete integrity. These results suggest that oyster gametes exposure to A. minutum blooms could affect oyster fertility and reproduction success.
