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Journal of Separation Science Apr 2019Okadaic acid is a marine biotoxin that primarily occurs in shellfish and can cause diarrheic shellfish poisoning in humans. When analyzing biological samples using...
Okadaic acid is a marine biotoxin that primarily occurs in shellfish and can cause diarrheic shellfish poisoning in humans. When analyzing biological samples using liquid chromatography with tandem mass spectrometry, the presence of complex matrices is a major issue. Thus, it is crucial to selectively and simply extract the target analyte from samples and minimize matrix effects simultaneously. To meet this need, an immunomagnetic-bead-based liquid chromatography with tandem mass spectrometry method was developed to detect okadaic acid in shellfish. Magnetic beads bound to monoclonal antibody against okadaic acid were used as affinity probes to specifically enrich okadaic acid in samples, which effectively eliminated matrix effects. A magnetic separator was used to aggregate and separate magnetic particles from sample matrices, and methanol was used to elute okadaic acid from the magnetic beads. Standard solution prepared with methanol was employed directly for quantitative analysis. Several experimental conditions were optimized to improve performance. The method is of interest as a rapid (10 min) sample clean-up and selective enrichment tool, and it showed good linearity and sensitivity, with reported limits of detection and quantitation of 3 and 10 μg/kg, respectively. Fifty-three shellfish samples from an aquatic products market were tested using this method, and four samples positive for okadaic acid were found.
Topics: Antibodies, Monoclonal; Antigen-Antibody Reactions; Chromatography, Liquid; Immunomagnetic Separation; Okadaic Acid; Shellfish; Tandem Mass Spectrometry
PubMed: 30667151
DOI: 10.1002/jssc.201800875 -
Food Chemistry Apr 2022Core-shell structured magnetic covalent-organic frameworks (FeO@TaTp) were facilely synthesized based on one-step functionalization at room temperature and applied for...
Core-shell structured magnetic covalent-organic frameworks for rapid extraction and preconcentration of okadaic acid in seawater and shellfish followed with LC-MS/MS quantification.
Core-shell structured magnetic covalent-organic frameworks (FeO@TaTp) were facilely synthesized based on one-step functionalization at room temperature and applied for magnetic solid-phase extraction of okadaic acid from seawater and shellfish prior to LC-MS/MS detection. Parameters, including adsorbent amount, extraction time, desorption solution, and desorption time which could affect the extraction efficiency, were respectively investigated. The developed methods demonstrated good linearity (R > 0.99), acceptable accuracy and good precision (<15%), and low limit of detection (0.5 pg·mL for seawater and 0.04 µg·kg for shellfish). The amount of the material used (1 mg for seawater and 5 mg for shellfish) and the time required (4 min for seawater and 15 min for shellfish) for extracting analyte from 5 mL of seawater and 2 g of shellfish are both greatly shortened compared with the previous reports. In addition, we successfully applied this method to real sample analysis.
Topics: Adsorption; Chromatography, Liquid; Limit of Detection; Magnetic Phenomena; Metal-Organic Frameworks; Okadaic Acid; Seawater; Shellfish; Solid Phase Extraction; Tandem Mass Spectrometry
PubMed: 35021580
DOI: 10.1016/j.foodchem.2021.131778 -
Ecotoxicology and Environmental Safety Sep 2023Okadaic acid (OA) is one of the most prevalent marine phycotoxin with complex toxicity, which can lead to toxic symptoms such as diarrhea, vomiting, nausea, abdominal...
Okadaic acid (OA) is one of the most prevalent marine phycotoxin with complex toxicity, which can lead to toxic symptoms such as diarrhea, vomiting, nausea, abdominal pain, and gastrointestinal discomfort. Studies have shown that the main affected tissue of OA is digestive tract. However, its toxic mechanism is not yet fully understood. In this study, we investigated the changes that occurred in the epithelial microenvironment following OA exposure, including the epithelial barrier and gut bacteria. We found that impaired epithelial cell junctions, mucus layer destruction, cytoskeletal remodeling, and increased bacterial invasion occurred in colon of rats after OA exposure. At the same time, the gut bacteria decreased in the abundance of beneficial bacteria and increased in the abundance of pathogenic bacteria, and there was a significant negative correlation between the abundance of pathogenic bacteria represented by Escherichia/Shigella and animal body weight. Metagenomic analysis inferred that Escherichia coli and Shigella spp. in Escherichia/Shigella may be involved in the process of cytoskeletal remodeling and mucosal layer damage caused by OA. Although more evidence is needed, our results suggest that opportunistic pathogens may be involved in the complex toxicity of OA during OA-induced epithelial barrier damage.
Topics: Animals; Rats; Okadaic Acid; Body Weight; Colon; Escherichia coli
PubMed: 37597294
DOI: 10.1016/j.ecoenv.2023.115376 -
Journal of Hazardous Materials Oct 2017Okadaic Acid (OA), a small seafood-borne toxin secreted by Dinophysis and Prorocentrum dinoflagellates, is generally distributed in various species of shellfish and has...
Okadaic Acid (OA), a small seafood-borne toxin secreted by Dinophysis and Prorocentrum dinoflagellates, is generally distributed in various species of shellfish and has caused diarrhetic shellfish poisoning (DSP). In view of OA toxin threat to humans and animals, it is essential to develop a rapid, accurate and sensitive method for the detection and quantification of OA in real samples. In this study, a monoclonal antibody named 10E8 was screened by cells fusion of Sp2/0 with spleen cells isolated from immunized mouse, and the isotype of McAb 10E8 was belonged to IgG1. The resulted McAb 10E8 displayed higher specificity to OA antigen, with the highest affinity of 2.66×10L/moL until now. Indirect competitive ELISA (ic-ELISA) indicated that the linear range to detect OA was 20-750ng/mL. The limit of detection (LOD) was 12pg/mL, and the recovery average was (84.04±5.08)%. The LOD of colloidal gold immunoassay by naked eye and strip reader was 1ng/mL and 100pg/mL, respectively, with an average recovery of (88.0275±4.4225)%. Therefore, the developed ELISA and colloidal gold immunoassay based on this McAb can be used for OA detection in real samples.
Topics: Animals; Antibodies, Monoclonal; Antigens; Bivalvia; Food Contamination; Gold Colloid; Haptens; Immunoassay; Limit of Detection; Okadaic Acid; Ovalbumin; Serum Albumin, Bovine; Shellfish
PubMed: 28648727
DOI: 10.1016/j.jhazmat.2017.06.030 -
Marine Drugs Apr 2022This paper examined the toxins naturally produced by marine dinoflagellates and their effects on increases in β-amyloid plaques along with tau protein... (Review)
Review
This paper examined the toxins naturally produced by marine dinoflagellates and their effects on increases in β-amyloid plaques along with tau protein hyperphosphorylation, both major drivers of Alzheimer's disease (AD). This approach is in line with the demand for certain natural compounds, namely those produced by marine invertebrates that have the potential to be used in the treatment of AD. Current advances in AD treatment are discussed as well as the main factors that potentially affect the puzzling global AD pattern. This study focused on yessotoxins (YTXs), gymnodimine (GYM), spirolides (SPXs), and gambierol, all toxins that have been shown to reduce β-amyloid plaques and tau hyperphosphorylation, thus preventing the neuronal or synaptic dysfunction that ultimately causes the cell death associated with AD (or other neurodegenerative diseases). Another group of toxins described, okadaic acid (OA) and its derivatives, inhibit protein phosphatase activity, which facilitates the presence of phosphorylated tau proteins. A few studies have used OA to trigger AD in zebrafish, providing an opportunity to test in vivo the effectiveness of new drugs in treating or attenuating AD. Constraints on the production of marine toxins for use in these tests have been considered. Different lines of research are anticipated regarding the action of the two groups of toxins.
Topics: Alzheimer Disease; Amyloid beta-Peptides; Animals; Dinoflagellida; Marine Toxins; Okadaic Acid; Plaque, Amyloid; Zebrafish; tau Proteins
PubMed: 35447926
DOI: 10.3390/md20040253 -
Harmful Algae May 2024This article presents the first results on shellfish toxicity in the Slovenian sea (Gulf of Trieste, Adriatic Sea) since the analytical methods for the detection of...
Okadaic acid as a major problem for the seafood safety (Mytilus galloprovincialis) and the dynamics of toxic phytoplankton in the Slovenian coastal sea (Gulf of Trieste, Adriatic Sea).
This article presents the first results on shellfish toxicity in the Slovenian sea (Gulf of Trieste, Adriatic Sea) since the analytical methods for the detection of biotoxins (PSP, ASP, DSP and other lipophilic toxins) in bivalve molluscs were included in the national monitoring program in 2013. In addition to toxins, the composition and abundance of toxic phytoplankton and general environmental characteristics of the seawater (surface temperature and salinity) were also monitored. During the 2014-2019 study period, only lipophilic toxins were detected (78 positive tests out of 446 runs), of which okadaic acid (OA) predominated in 97 % of cases, while dinophysistoxin-2 and yessotoxins only gave a positive result in one sampling event each. The number of samples that did not comply with the EC Regulation for the OA group was 17 or 3.8 % of all tests performed, all of which took place from September to November, while a few positive OA tests were also recorded in December, April, and May. This toxicity pattern was consistent with the occurrence pattern of the five most common DSP-producing dinoflagellates, which was supported by the development of warm and thermohaline stratified waters: Dinophysis caudata, D. fortii, D. sacculus, D. tripos and Phalacroma rotundatum. The strong correlation (r = 0.611, p < 0.001) between D. fortii, reaching abundances of up to 950 cells L, and OA suggests that D. fortii is the main cause of OA production in Slovenian waters. Strong interannual variations in OA and phytoplankton dynamics, exacerbated by the effects of anthropogenic impacts in this coastal ecosystem, reduce the predictability of toxicity events and require continuous and efficient monitoring. Our results also show that the introduction of the LC-MS/MS method for lipophilic toxins has improved the management of aquaculture activities, which was not as accurate based on mouse bioassays.
Topics: Okadaic Acid; Animals; Phytoplankton; Marine Toxins; Slovenia; Mytilus; Seafood; Seawater; Dinoflagellida
PubMed: 38830710
DOI: 10.1016/j.hal.2024.102632 -
Combinatorial Chemistry & High... 2021The present study aims to investigate the effect of flavonoids from stem and leaf of Scutellaria Baicalensis Georgi (SSF) on multi-sites phosphorylation of tau protein...
Flavonoids from Stem and Leaf of Scutellaria Baicalensis Georgi Inhibit the Phosphorylation on Multi-sites of Tau Protein Induced by Okadaic Acid and the Regulative Mechanism of Protein Kinases in Rats.
AIM
The present study aims to investigate the effect of flavonoids from stem and leaf of Scutellaria Baicalensis Georgi (SSF) on multi-sites phosphorylation of tau protein in the cerebral cortex and hippocampus of rats induced by okadaic acid (OA) and the regulative mechanism of the protein kinases.
METHODS
The model of AD-like memory impairment and neuronal injuries was established in male SD rats who were microinjected with OA (200 ng/kg) to establish a memory impairment model and screened for successful model rats by Morris water maze on day 21 after surgery. The successful model rats were continuously administered with intragastric infusion (ig) SSF 25, 50 and 100 mg/kg or Ginkgo biloba leaves flavonoids (GLF) 200 mg/kg for 36 d. The relative protein expressed levels of phosphorylated tau protein at sites of Ser199, Ser202, Ser214, Ser404 and Thr231, protein kinases (CDK5, PKA, pTyr216-GSK3β and pSer9-GSK3β) were detected by Western blotting.
RESULTS
The relative protein expressed levels of p-tau(Ser199), p-tau(Ser202), p-tau(Ser214), p-- tau(Ser404), p-tau(Thr231) and pTyr216-GSK3β were significantly increased in both cerebral cortex and hippocampus regions of the model rats subjected to intracerebroventricular injection of OA (P<0.01), while the protein expressed levels of CDK5, PKA and pSer9-GSK3β (P<0.01) were reduced. SSF can dramatically reverse these increments in phosphorylated tau protein levels (P<0.01) and differently regulate the protein expressed levels of CDK5, PKA and GSK3β (P<0.01) in rats' cerebral cortex and hippocampus induced by OA. GLF also exhibit a similar effect to SSF.
CONCLUSION
The results demonstrated that SSF could inhibit the hyperphosphorylation of tau in rats' cerebral cortex and hippocampus induced by microinjection of OA, which may be related to the activities of protein kinase CDK5, PKA and GSK3β.
Topics: Animals; Cognitive Dysfunction; Disease Models, Animal; Flavonoids; Male; Okadaic Acid; Phosphorylation; Plant Leaves; Plant Stems; Protein Kinases; Rats; Rats, Sprague-Dawley; Scutellaria baicalensis; tau Proteins
PubMed: 32875975
DOI: 10.2174/1386207323666200901101233 -
Archives of Toxicology Aug 2021The consumption of contaminated shellfish with okadaic acid (OA) group of toxins leads to diarrhoeic shellfish poisoning (DSP) characterized by a set of symptoms...
The consumption of contaminated shellfish with okadaic acid (OA) group of toxins leads to diarrhoeic shellfish poisoning (DSP) characterized by a set of symptoms including nausea, vomiting and diarrhoea. These phycotoxins are Ser/Thr phosphatase inhibitors, which produce hyperphosphorylation in cellular proteins. However, this inhibition does not fully explain the symptomatology reported and other targets could be relevant to the toxicity. Previous studies have indicated a feasible involvement of the nervous system. We performed a set of in vivo approaches to elucidate whether neuropeptide Y (NPY), Peptide YY (PYY) or serotonin (5-HT) was implicated in the early OA-induced diarrhoea. Fasted Swiss female mice were administered NPY, PYY(3-36) or cyproheptadine intraperitoneal prior to oral OA treatment (250 µg/kg). A non-significant delay in diarrhoea onset was observed for NPY (107 µg/kg) and PYY(3-36) (1 mg/kg) pre-treatment. On the contrary, the serotonin antagonist cyproheptadine was able to block (10 mg/kg) or delay (0.1 and 1 mg/kg) diarrhoea onset suggesting a role of 5-HT. This is the first report of the possible involvement of serotonin in OA-induced poisoning.
Topics: Animals; Cyproheptadine; Diarrhea; Enzyme Inhibitors; Female; Mice; Neuropeptide Y; Okadaic Acid; Peptide Fragments; Peptide YY; Serotonin; Serotonin Antagonists; Shellfish Poisoning; Time Factors
PubMed: 34148100
DOI: 10.1007/s00204-021-03095-z -
Cellular Physiology and Biochemistry :... 2018Okadaic acid (OA) and the structurally related compounds dinophysistoxin-1 (DTX1) and dinophysistoxin-2 (DTX2) are marine phycotoxins that cause diarrheic shellfish...
BACKGROUND/AIMS
Okadaic acid (OA) and the structurally related compounds dinophysistoxin-1 (DTX1) and dinophysistoxin-2 (DTX2) are marine phycotoxins that cause diarrheic shellfish poisoning (DSP) in humans due to ingestion of contaminated shellfish. In order to guarantee consumer protection, the regulatory authorities have defined the maximum level of DSP toxins as 160 µg OA equivalent kg-1 shellfish meat. For risk assessment and overall toxicity determination, knowledge of the relative toxicities of each analogue is required. In absence of enough information from human intoxications, oral toxicity in mice is the most reliable data for establishing Toxicity Equivalence Factors (TEFs).
METHODS
Toxins were administered to mice by gavage, after that the symptomatology and mice mortality was registered over a period of 24 h. Organ damage data were collected at necropsy and transmission electron microscopy (TEM) was used for ultrastructural studies. Toxins in urine, feces and blood were analyzed by HPLC-MS/MS. The evaluation of in vitro potencies of OA, DTX1 and DTX2 was performed by the protein phosphatase 2A (PP2A) inhibition assay.
RESULTS
Mice that received DSP toxins by gavage showed diarrhea as the main symptom. Those toxins caused similar gastrointestinal alterations as well as intestine ultrastructural changes. However, DSP toxins did not modify tight junctions to trigger diarrhea. They had different toxicokinetics and toxic potency. The lethal dose 50 (LD50) was 487 µg kg-1 bw for DTX1, 760 µg kg-1 bw for OA and 2262 µg kg-1 bw for DTX2. Therefore, the oral TEF values are: OA = 1, DTX1 = 1.5 and DTX2 = 0.3.
CONCLUSION
This is the first comparative study of DSP toxins performed with accurate well-characterized standards and based on acute toxicity data. Results confirmed that DTX1 is more toxic than OA by oral route while DTX2 is less toxic. Hence, the current TEFs based on intraperitoneal toxicity should be modified. Also, the generally accepted toxic mode of action of this group of toxins needs to be reevaluated.
Topics: Administration, Oral; Animals; Body Weight; Chromatography, High Pressure Liquid; Female; Heart; Intestine, Small; Liver; Mice; Myocardium; Okadaic Acid; Protein Phosphatase 2; Pyrans; Stomach; Tandem Mass Spectrometry; Toxicity Tests
PubMed: 30176657
DOI: 10.1159/000493039 -
Food Additives & Contaminants. Part A,... 2015Harmful algae blooms (HABs) are the main source of marine toxins in the aquatic environment surrounding the austral fjords in Chile. Huichas Island (Aysén) has an...
Harmful algae blooms (HABs) are the main source of marine toxins in the aquatic environment surrounding the austral fjords in Chile. Huichas Island (Aysén) has an history of HABs spanning more than 30 years, but there is limited investigation of the bioaccumulation of marine toxins in the bivalves and gastropods from the Region of Aysén. In this study, bivalves (Mytilus chilenses, Choromytilus chorus, Aulacomya ater, Gari solida, Tagelus dombeii and Venus antiqua) and carnivorous gastropods (Argobuccinum ranelliformes and Concholepas concholepas) were collected from 28 sites. Researchers analysed the accumulation of STX-group toxins using a LC with a derivatisation post column (LC-PCOX), while lipophilic toxins (OA-group, azapiracids, pectenotoxins and yessotoxins) were analysed using LC-MS/MS with electrospray ionisation (+/-) in visceral (hepatopancreas) and non-visceral tissues (mantle, adductor muscle, gills and foot). Levels of STX-group and OA-group toxins varied among individuals from the same site. Among all tissue samples, the highest concentrations of STX-group toxins were noted in the hepatopancreas in V. antiqua (95 ± 0.1 μg STX-eq 100 g(-1)), T. dombeii (148 ± 1.4 μg STX-eq 100 g(-1)) and G. solida (3232 ± 5.2 μg STX-eq 100 g(-1); p < 0.05); in the adductor muscle in M. chilensis (2495 ± 6.4 μg STX-eq 100 g(-1); p < 0.05) and in the foot in C. concholepas (81 ± 0.7 μg STX-eq 100 g(-1)) and T. dombeii (114 ± 1.2 μg STX-eq 100 g(-1)). The highest variability of toxins was detected in G. solida, where high levels of carbamate derivatives were identified (GTXs, neoSTX and STX). In addition to the detected hydrophilic toxins, OA-group toxins were detected (OA and DTX-1) with an average ratio of ≈1:1. The highest levels of OA-group toxins were in the foot of C. concholepas, with levels of 400.3 ± 3.6 μg OA eq kg(-1) (p < 0.05) and with a toxic profile composed of 90% OA. A wide range of OA-group toxins was detected in M. chilensis with a toxicity < 80 μg OA eq kg(-1), but with 74% of those toxins detected in the adductor muscle. In all evaluated species, there was no detection of lipophilic toxins associated with biotransformation in molluscs and carnivorous gastropods. In addition, the STX-group and OA-group toxin concentrations in shellfish was not associated with the presence of HAB. The ranking of toxin concentration in the tissues of most species was: digestive glands > mantle > adductor muscle for the STX-group toxins and foot > digestive gland for the OA-group toxins. These results gave a better understanding of the variability and compartmentalisation of STX-group and OA-group toxins in different bivalve and gastropod species from the south of Chile, and the analyses determined that tissues could play an important role in the biotransformation of STX-group toxins and the retention of OA-group toxins.
Topics: Animals; Biotransformation; Bivalvia; Chile; Chromatography, Liquid; Gastropoda; Harmful Algal Bloom; Meat; Okadaic Acid; Saxitoxin; Shellfish Poisoning; Tandem Mass Spectrometry
PubMed: 25769036
DOI: 10.1080/19440049.2015.1028107