Streptococcal toxic shock syndrome (STSS) is a fulminant manifestation of invasive group A Streptococcus infection characterized by superantigen-driven hyperinflammation, refractory shock, and rapidly progressive multiorgan dysfunction. Despite antimicrobial therapy, source control, intravenous immunoglobulin, and intensive organ support, some patients deteriorate rapidly, prompting interest in extracorporeal immunomodulation. This narrative review examines the biological rationale and clinical experience of hemoadsorption in STSS, supported by an illustrative case and comparison with published reports. Our patient developed vasopressor-dependent shock, acute kidney injury, thrombocytopenia, hepatic and myocardial injury, hyperlactatemia, and metabolic acidosis within 48 h. CytoSorb was integrated with continuous venovenous hemofiltration during ongoing deterioration, followed by hemodynamic and organ recovery; however, concurrent therapies preclude attribution of benefit to hemoadsorption. Published cases show a similar pattern, with extracorporeal escalation initiated during refractory shock and accumulating organ dysfunction rather than at a predefined biomarker threshold. Although experimental and observational evidence supports the biological activity of hemoadsorption, clinical evidence remains insufficient to establish a survival benefit. Current evidence does not support routine hemoadsorption for STSS. A rapidly progressive, multidimensional hyperinflammatory trajectory may instead provide a framework for future studies of patient selection and treatment timing.
Tropical regions are characterized by exceptional biodiversity, including extremely diverse flora. Many plants produce chemical compounds that function as defense mechanisms, some of which are toxic to mammals, including livestock species. However, documentation of toxic plants in the Caribbean region remains limited. The present study aimed to identify toxic and potentially toxic plant species affecting livestock on the island of Saint Christopher (St. Kitts) through surveys of a representative number of farms across all nine parishes. An extensive literature review was performed in order to characterize the local flora and to identify plant species with known or suspected toxic potential. Farm visits were conducted using a structured surveillance questionnaire developed by the authors. During these visits, representative photographs of commonly encountered toxic plants were taken. The identified plant species were classified according to the chemical nature of their active ingredient, and their main clinical effects were described. Ten plant species (Abrus precatorius, Senna occidentalis, Catharanthus roseus, Crotalaria retusa, Datura stramonium, Manihot esculenta, Mimosa pudica, Nerium oleander, Nicotiana tabacum and Ricinus communis) were found to be widespread throughout the island and have been documented in the literature as toxic to livestock. By knowing the distribution of these species, high-risk areas and pastures can be identified, thereby supporting targeted prevention and more effective management of future plant-associated toxicosis outbreaks.
Forests are an indispensable resource for human existence in the different regions of the world. Forests are often concentrated in a few parts and vary in size. The most important and extensive green reserve on Earth is the Amazon rainforest. Unfortunately, the forests are continually suffering massive losses due to abiotic stresses and deforestation to obtain other arable lands and microbial diseases, particularly those caused by pathogenic fungi. Pathogenic fungi play an important role in inducing oak decline, which is one of the most relevant forest diseases globally. The pathogens also affect disease development and its global distribution. In this review, the phytotoxins produced by fungal pathogens of different oak species in various world regions are described in depth. In particular, the isolation, the chemistry and biology of phytotoxins synthesized by oak pathogenic fungi are reported, and their role in pathogenesis is also discussed. For some phytotoxins, the enantioselective synthesis, the structure–biological activity relationships, and their utilization in agro-industry and medical applications are also discussed. In addition, for the Diplodia species, the comparison between their secondary metabolite profile and taxonomy with those of fungal pathogens of other close forest plants is discussed. Thus, fungal diseases of numerous oak trees and the serious damages they cause to the forest heritage are described, as well as the chemical and biological properties and results of some of the structure–activity relationship (SAR) studies of the phytotoxins involved. In addition, for the Diplodia species both phylogenetically closely related and unrelated, comparison between their secondary metabolite profile with those of pathogens of other close forest plants, in combination with traditional taxonomic characteristics, has helped to better understand the pathogenic process relationships within the same fungal f the pathogenic process within the same fungal family.
Mycotoxin contamination in food and feed remains a major public health concern because of its potential toxicological impact and its global economic implications. Aflatoxins and ochratoxin A are of particular concern due to their carcinogenic, hepatotoxic, and nephrotoxic effects, highlighting the need for effective surveillance systems to reduce dietary exposure in the population. This study analyzes 2479 mycotoxin-related notifications concerning both food and feed reported through the iRASFF system during the period 2020–2024, with the aim of characterizing temporal notification trends, identifying the most affected food products and geographical regions, and evaluating the evolution of control strategies implemented by competent authorities. The results did not show a statistically significant long-term increasing trend in the number of mycotoxin notifications, although interannual fluctuations may reflect both changes in contamination patterns and improvements in detection and reporting systems. Products originating outside the European Union accounted for 90.44% of notifications and showed a significantly higher mean number of notifications than products originating within the European Union. Turkey (24%) and the United States (14%) were the most frequently reported countries of origin at a global level. Aflatoxins were the most frequently detected mycotoxins in food (84%), followed by ochratoxin A (15%), mainly affecting nuts, cereals, fruits, vegetables and herbs and spices. These findings demonstrate that mycotoxins continue to represent a persistent challenge for European food safety. Strengthening surveillance systems, enhancing international cooperation, and adapting control strategies to emerging environmental and trade-related factors are essential to minimize consumer exposure, particularly to compounds with genotoxic and carcinogenic potential, and to improve risk management within the food supply chain.
Zearalenone (ZEN) is a mycotoxin produced by Fusarium species that is harmful to agricultural crops. Therefore, the prevention and control of ZEN contamination is an important concern for food safety. Lactobacillus paracasei 85 is a well-recognized probiotic with considerable potential for mycotoxin biocontrol owing to its diverse probiotic properties and antimicrobial activity. Based on its reported potential, we aimed to evaluate its ability to degrade ZEN using degradation assays under optimal conditions. Transcriptome sequencing, untargeted metabolomics, and integrated bioinformatics analyses were conducted to explore the molecular mechanisms underlying ZEN removal. Transcriptomic analysis showed that the strain activated central carbon and secondary metabolism during ZEN removal, and all seven differentially expressed genes closely related to carbohydrate metabolism were downregulated. Metabolomic analysis revealed that lipid and amino acid metabolism, in addition to carbohydrate metabolism, played important roles in ZEN removal. Correlation analysis between carbohydrate metabolism-related genes and their metabolites revealed that these genes were significantly associated with four metabolites: myo-inositol, guanosine, glycolic acid, and trehalose. As key nodes in the carbohydrate metabolism pathway, changes in the expression of these four metabolites and their interactions with genes may represent key regulatory factors responsible for the overall downregulation of carbohydrate metabolism.
Fusarium mycotoxins are major contaminants of human and animal feed and pose significant risks to health. A recent recommendation from the European Commission drastically decreased the maximum tolerated concentrations of fumonisins (FBs) and deoxynivalenol (DON) in poultry feed. The objectives of this study were to characterize the effects of a 14-day exposure to a diet containing 7.5 mg FB1 + FB2/kg, 2.5 mg DON/kg and 0.6 mg zearalenone (FDZ diet) in turkeys and chickens, and to assess the persistence of these effects following withdrawal of the contaminated diet. No clinical signs of toxicity were observed in either species, and markers of hepatic oxidative damage remained unchanged. In contrast, sphingolipidome alterations were detected, being more pronounced in turkeys than chickens and more persistent in the liver than in plasma. The C22–C24:C16 ratios measured across several sphingolipid (SL) classes emerged as sensitive biomarkers of FB exposure, whereas the sphinganine:sphingosine ratio (Sa:So) remained unchanged. Determination of the 90th percentile (P90) thresholds for SL ratios in unexposed animals provided good-to-excellent discrimination between exposed and unexposed animals. Notably, this conservative percentile-based approach detected FB exposure using the Sa:So ratio despite the absence of significant differences in group means. Multivariate analysis of the complete sphingolipidome provided the highest discriminatory power, distinguishing exposed from unexposed turkeys and chickens for up to four days after withdrawal of the FDZ diet. Finally, the biological significance of alterations in d18:1P, 18:0/2:0, 18:1/16:0, and dihydrosphingolipids induced by the FDZ diet is discussed.
Cervical dystonia (CD) is a hyperkinetic movement disorder characterized by involuntary muscle contractions leading to abnormal postures of the head and neck. The injection of botulinum neurotoxin type A (BoNT-A) into the muscles involved is the treatment of choice for CD. BoNT-A therapy of CD requires appropriate training, which has not been standardized in Germany. To address the key challenges in BoNT-A education, an expert panel developed a simplified step-by-step treatment guideline for beginners, adapted from the established Col-Cap-Concept (“Dystonia 3×3”). Based on expert consensus, recommendations were developed for the core clinical elements of BoNT-A treatment in CD—recognition of the movement pattern, identification of target muscles, development of an injection plan, ultrasound-guided injection, and dosing, taking into account the target audience of the guideline. As such, Dystonia 3×3 provides a user-friendly beginner’s guidebook, enhancing accessibility and standardization of CD treatment training. Further research is required to evaluate its clinical efficacy and suitability for training.
Wheat, soy and pea protein isolates used for the production of plant-based meat alternatives were analyzed for 87 mycotoxins and 26 plant toxins by means of a validated QuEChERS-based LC-MS/MS multi-method. For wheat gluten, the results revealed the presence of Alternaria toxins, deoxynivalenol, enniatins, ergot alkaloids and ochratoxin A (OTA). For soy protein, beauvericin, enniatin B and OTA were the most frequently detected mycotoxins, while for pea protein, OTA was the most frequently detected mycotoxin. From plant toxins, the tropane alkaloids atropine and scopolamine were detected in wheat gluten and soy protein. The emerging Alternaria toxin alterperylenol was reported for the first time in wheat gluten (85% of samples). OTA was present at high levels in all three matrices (exceeding the EU maximum level in one wheat gluten sample). Ergot alkaloids were found in 95% of wheat gluten samples, but none exceeded the ML. The highest co-occurrence of different toxins was observed in wheat gluten (median: 22, max: 27 toxins/sample), followed by soy protein (median: five, max: nine toxins/sample) and pea protein (median: one, max: five toxins/sample).
In recent decades, the problem of harmful algal blooms (HABs) in various water bodies has gained widespread recognition worldwide [...]
Post-stroke spasticity may interfere with function and rehabilitation and contribute to pain, contracture, care burden, and disability. Botulinum toxin type A is an established focal treatment for post-stroke spasticity, but it is often introduced in the chronic phase, when persistent involuntary muscle overactivity may coexist with secondary musculoskeletal complications. This opinion paper critically examines whether early treatment with botulinum toxin should be considered a myth or an emerging clinical reality. Current evidence from meta-analyses, randomized trials, observational cohorts, and pooled analyses was reviewed with particular attention to treatment timing, treatment triggers, functional outcomes, and prevention of secondary complications. The literature supports the clinical usefulness of earlier treatment in appropriately selected patients, particularly for reducing focal involuntary muscle overactivity and resistance to passive movement, delaying symptomatic progression, slowing contracture development, and reducing pain-related complications. However, a consistent additional effect on active motor recovery has not been demonstrated, and evidence for participation and long-term functional independence remains less definitive. Moreover, “early” is heterogeneously defined across studies, ranging from the first weeks to the first year after stroke. We therefore propose moving from a rigid time-based concept of “early” treatment toward timely, target- and goal-guided intervention, integrating botulinum toxin with rehabilitation when a clinically relevant and modifiable focal neural treatment target emerges. To operationalize this concept, we propose a pragmatic set of clinical variables including the neural treatment target, its clinical impact and trajectory, passive musculoskeletal status, pain and care burden, motor recovery context, rehabilitation goals, and patient priorities.
Mycotoxin contamination remains a persistent threat to food and feed safety owing to the chemical stability of many mycotoxins, frequent co-occurrence, and matrix-dependent risks. Enzymatic detoxification enables structure-targeted transformation of toxicity-determining motifs, such as epoxide rings, reactive double bonds, amide linkages, and lactone structures. However, free mycotoxin-degrading enzymes are often constrained by poor operational stability, difficult recovery, and limited adaptability to complex matrices. Metal–organic frameworks (MOFs) provide programmable microenvironments for enzyme immobilization through tunable pore structures, interfacial chemistry, and confinement effects. This review links toxic structural motifs with enzymatic transformation targets, discusses MOF–enzyme interface engineering and representative host–enzyme compatibility, and evaluates application modes including single-enzyme systems, multi-enzyme co-immobilization or cascade systems, adsorption–degradation coupling, and detection–degradation integration. Key bottlenecks involving enzyme leakage, mass-transfer limitation, real-matrix stability, scalable preparation, and biosafety are critically discussed. Rather than treating MOFs as passive enzyme carriers, this review proposes an application-oriented framework that integrates toxin structure, enzyme function, MOF interface regulation, matrix compatibility, and safety validation to guide the development of MOF-immobilized degrading enzymes for practical mycotoxin detoxification.
Pregnancy-related acute kidney injury (PR-AKI) increases the risk of chronic kidney disease (CKD) in the postpartum period, yet mechanisms driving this transition remain unclear. Uremic toxins, including indoxyl sulfate (IS), are implicated in AKI-to-CKD progression. Using a rat model of PR-AKI induced by ischemia–reperfusion on gestational day (GD) 18, we assessed IS contributions to renal injury in the postpartum. A subset of rats received the oral adsorbent AST-120 in the postpartum period to reduce IS. Additional groups received IS during pregnancy with or without AST-120 treatment in the postpartum period. Renal function, blood pressure, circulating and urinary IS concentrations, and renal histopathology were evaluated. PR-AKI resulted in sustained postpartum elevations in circulating (p = 0.03) and urinary (p < 0.03) IS, reduced urine output (p = 0.03), increased proteinuria (p < 0.0001), increased serum albumin, and increased renal fibrosis (p = 0.008) compared to normal pregnant control rats. Absorption of indole, a precursor for IS, significantly reduced urinary IS (p = 0.03), reduced serum creatinine (p = 0.006), and attenuated renal fibrosis (p = 0.002) in treated PR-AKI rats. While not significant, indole absorption improved urine output (p = 0.06) and reduced proteinuria (p = 0.07) in treated PR-AKI rats. IS administration during pregnancy recapitulated key features of postpartum CKD. Elevated IS contributes to persistent renal injury following PR-AKI. Postpartum reduction in IS with AST-120 dampens the progression of renal injury. These findings highlight uremic toxins as mechanistic drivers and potential therapeutic targets in post partum CKD following PR-AKI.
Aflatoxin B1 (AFB1) is a highly toxic mycotoxin which can be carried over into animal products and cause deterioration of livestock productivity when fed to livestock and wildlife. This review proposes a biomarker-guided framework for improving the early assessment of AFB1 exposure and toxicological responses in animal models. Oral exposure leads to the absorption of AFB1, which is bioactivated in the liver to the reactive AFB1-exo-8,9-epoxide that causes DNA and protein adduct formation, inflammation, mitochondrial apoptosis, and other effects. Cytochrome P450 activation and glutathione-dependent detoxification are in balance in determining susceptibility species, and this balance is different for poultry, pigs, ruminants, and rodents. In addition to traditional liver enzymes and histopathology, we highlight mechanistically informative biomarkers such as metabolites of aflatoxin, DNA and albumin adduct, lipid peroxidation products, antioxidant indices, cytokines, apoptotic markers, as well as signals involved in the Nrf2/NFκB pathway. AFB1 also damages the integrity of the intestinal barrier, the maintenance of the intestinal gut microbiota, reproductive function, growth performance, and development, thus creating a gut–liver-systemic toxic cascade. Finally, an assessment of stage-targeted interventions such as aluminosilicate binders, adsorbents derived from yeast, probiotics and nano-enabled interventions is conducted as viable tools for the reduction in exposure and injury. This review offers targeted mitigation strategies for early diagnosis of aflatoxicosis in animal production systems based on a biomarker approach.
Phytochemicals with antifungal activity against Fusarium graminearum (F. graminearum) are considered potential in-feed anti-mycotoxigenic agents that may complement conventional post-harvest control strategies. Therefore, we screened fourteen phytochemicals, including seven quinolizidine alkaloids (QAs), for anti-F. graminearum activity, evaluated their individual and combined efficacy in inhibiting mycelial growth, spore germination, and deoxynivalenol (DON) production, and explored the underlying mechanisms via transcriptomic analysis. Matrine (MT), sophoridine (SR), and sophocarpine (SC) exhibited antifungal activity against F. graminearum, with minimum inhibitory concentrations (MICs) of 5, 4, and 4 mg/mL, respectively. The three QAs at their MICs completely inhibited mycelial growth and DON production in liquid cultures, but were less effective on potato dextrose agar plates and in pig feed. Particularly pronounced antifungal activity and inhibitory effects on DON production were observed when the three QAs were applied in combination with berberine hydrochloride (BBR). The observed inhibition appears to be attributed to dysregulated expression of the TRI cluster genes and ERG biosynthesis genes, coupled with significant modulation of steroid biosynthesis (ko00100) and central carbon/lipid metabolism pathways. These findings provide preliminary experimental evidence supporting the further exploration of QA–BBR combinations to control fungal proliferation and DON accumulation in pig feed.
The interaction between modified forms of deoxynivalenol (DON), such as DON-3-glucoside (DON-3G), and feed enzymes is underestimated. We assessed the interaction between DON and non-starch polysaccharide enzymes (NSPases) on growth performance, and excreta levels of DON and its metabolites (Experiment 1), as well as DON toxicokinetics (Experiment 2). Broiler chickens were fed maize-based diets naturally contaminated with low (LD; 516–792 μg DON/kg diet) or moderate (MD; 2395–3020 μg DON/kg diet) levels of DON. The LD and MD diets were supplemented with or without an NSPase blend. The MD diet impaired growth performance in broiler chickens up to 14 days of age, whereas no differences were observed in older birds. NSPase supplementation decreased body weight gain (BWG) in 28-day-old broiler chickens fed the MD diet and increased excreta levels of DON-3-sulfate (DON-3S). NSPase supplementation also improved the feed conversion ratio (FCR) without increasing BWG. Additionally, NSPase altered the toxicokinetic profile of DON in broiler chickens fed the MD diet, and the time to maximum plasma concentration (Tmax) of DON-3S was influenced by both NSPase supplementation and the DON level in the diet. To our knowledge, these findings provide the first evidence that NSPases influence DON toxicokinetics in poultry.
Hymenopteran venoms contain diverse proteins and peptides that shape envenomation, defense, predation, and allergic responses. Honeybee venom from Apis mellifera is well characterized, while molecular resources for the Asian giant hornet Vespa mandarinia remain less curated. We compared protein- and peptide-fraction LC-MS/MS identification datasets from V. mandarinia venom (VM-V) and A. mellifera venom (AM-V), supported by a de novo V. mandarinia transcriptome-derived database. Protein-level identification yielded 197 protein groups in VM-V PRO and 164 protein groups in AM-V PRO. AM-V contained well-recognized honeybee venom components, including phospholipase A2, hyaluronidase, venom acid phosphatase, venom dipeptidyl peptidase 4, melittin precursor, mast cell degranulating peptide precursor, secapin, and allergen Api m 6. VM-V PRO contained transcriptome-supported candidate venom-associated proteins, including venom dipeptidyl peptidase 4-like, hyaluronidase-like, venom allergen 5-like, serine protease-like, apolipophorin-like, and hexamerin-like entries. Peptide-fraction annotation was strongest in AM-V PEP, led by melittin precursor, whereas VM-V PEP remained largely unannotated. The study focuses on identification, annotation, and hypothesis-generating functional summaries, not replicate-level differential abundance. GO, KEGG, and STRING analyses organized functional annotation patterns and prioritized candidate protein groups. These data provide an identification-based comparative venomomics resource for VM-V and AM-V and a foundation for targeted validation of candidate V. mandarinia venom-associated components.
Mycotoxins contaminate a wide range of foods and may contribute to both acute toxicity and chronic dietary exposure. Because online video increasingly shapes public interpretation of food-safety hazards, we evaluated the quality of English-language YouTube™ content on foodborne mycotoxin risks. Of 166 records screened for eligibility, 53 were excluded and 113 videos were analyzed. Two food-safety experts independently evaluated each video with an investigator-developed Video Content Quality (VCQ) checklist, the Global Quality Scale (GQS), and a five-item modified DISCERN instrument. The final sample comprised 77 company/commercial and 36 academic/noncommercial videos. After Holm adjustment across five source-group outcomes, company/commercial videos had higher VCQ and modified DISCERN scores (both adjusted p < 0.001), whereas academic/noncommercial videos had a higher interaction rate (adjusted p = 0.024). The GQS comparison did not meet the adjusted significance threshold (adjusted p = 0.066) and should not be interpreted as proof of equivalence. Video age was associated with cumulative views and likes but not with any quality score after correction. Item-level VCQ results showed that authoritative-source citation and health-effects coverage were among the least frequently awarded full-credit domains. Although the three quality measures were strongly correlated, neither interaction rate nor viewing rate was significantly associated with them. Platform engagement therefore did not serve as a reliable marker of scientific quality in this sample. Source- and region-based comparisons remain exploratory because the single-query design, broad uploader categories, and uneven source composition may have shaped the sampled videos.
Background: Ochratoxin A (OTA) is a widespread mycotoxin with well-established nephrotoxic, immunotoxic, and carcinogenic properties. Despite decades of research, the structure, thematic evolution, and emerging directions of the scientific literature on OTA toxicity remain incompletely mapped. Methods: A bibliometric analysis was conducted using 883 publications indexed in the Web of Science Core Collection (1965–2025). Bibliometrix, VOSviewer, and BibExcel were integrated within a comparative cross-software workflow to assess publication trends, collaboration networks, thematic evolution, and thematic research directions in in vitro and in vivo OTA toxicity studies, while enabling cross-validation of the main bibliometric outputs. Results: After normalisation, authors, journals, author keywords, and Keywords Plus showed strong cross-software agreement, whereas country and institution outputs retained software dependent differences related mainly to country aggregation and affiliation parsing. Publication output increased substantially over the analysed period, particularly during the most recent decade, reflecting the growing visibility of OTA research in food safety and toxicology. The field is highly collaborative and multidisciplinary. Oxidative stress-related terms were prominent in the keyword and thematic analyses and co-occurred with terminology related to apoptosis, DNA damage, and mitochondrial dysfunction. Thematic evolution analyses showed a transition from early studies focused on nephrotoxicity and animal models toward more recent investigations addressing molecular pathways, cellular responses, and microbiota host interactions. Comparatively less prominent or emerging bibliometric themes included the gut immune axis, co-exposure to multiple mycotoxins, and the broader representation of animal-health and productivity-related research. Conclusions: The bibliometric and science mapping analyses indicate that the literature on OTA toxicity has evolved from predominantly organ, and animal model-related research, toward increasing attention to molecular, cellular, intestinal, and microbiota-related topics. These patterns describe changes in the conceptual structure of the literature rather than direct evidence of biological causality. Comparatively, less prominent themes, including human-relevant models, combined exposure scenarios, and microbiome-related research, may warrant further investigation.
Aflatoxin 1. (AFB1) threatens animal health and dairy safety, but mammary-protective interventions remain poorly defined. We evaluated whether S-methylmethionine (SMM; commonly known as vitamin U) attenuates AFB1-associated injury using MAC-T bovine mammary epithelial cells, a mouse mammary model, biochemical assays, RT-qPCR, Western blotting, H&E staining, and exploratory ATAC-seq/RNA-seq analysis. Under 4 μg/mL (approximately 12.81 μM) AFB1 challenge, 1 mM SMM increased MAC-T cell viability by 14.1% (Tukey-adjusted p = 0.0387) and reduced LDH release by 38.2% (p = 0.000236) relative to the AFB1-only group. SMM also shifted selected redox markers toward a less injured state. Nrf2 protein abundance differed between the AF and AU groups (p = 0.049), although pathway activation and causal dependence were not tested. In mice, SMM co-treatment reduced serum ALT by 38.5% and mammary MDA by 56.4%, while increasing mammary T-SOD by 85.4% and GSH-Px by 100.9% relative to AF (p < 0.05 for the reported pairwise comparisons); inflammatory transcripts changed non-uniformly. The AU-versus-AF integration yielded four exploratory candidate genes (TNFSF10, NBEAL1, ENSBTAG00000054644, and ENSBTAG00000052086), and the selected RT-qPCR results were directionally consistent with the RNA-seq data. Thus, SMM attenuated selected AFB1-associated injury features under the tested conditions, while the underlying mechanism remains unresolved.
A previously overlooked isomer of okadaic acid (OA), which is structurally related to dinophysistoxin-2 (DTX2), was identified in bivalves and water columns from the Northwest Iberian Peninsula. This isomer elutes chromatographically after DTX2 and before DTX1, with mass spectrometric fragmentation patterns distinct from those of OA. It occurs at lower concentrations than OA but at levels comparable to DTX2, showing a consistent presence since monitoring by LC-MS/MS began in 2014. The abundance of this isomer correlated more strongly with OA than with DTX2, suggesting that it originates mainly from phytoplankton species that do not produce DTX2. Seasonal patterns revealed two maxima for the isomer, aligning with OA but differing from the single autumn–winter maximum of DTX2. Spatially, the isomer followed a northeast–southwest gradient along the Galician coast, similar to the OA and DTX2 distributions. The esterification rates of the isomer in mussels are lower than those of OA but similar to those of DTX2, likely resulting in slower depuration and longer persistence. Temporal trends indicate a recent increase in the concentration and seasonality of the isomer, rendering it more conspicuous. These findings highlight the growing significance of this isomer in shellfish toxin profiles throughout the studied period, underscoring the need to determine its structure and potential toxicity to better assess risks to human health.
