Toxins最新文献

Cephalothrix cf. simula is a highly toxic ribbon worm of the class Palaeonemertea, known for its high concentrations of tetrodotoxin. Recent transcriptomic and proteomic studies across Nemertea have revealed that species from all classes possess a diverse array of protein and peptide toxins, which are associated with unicellular glands of the proboscis and the integument epithelium. Previous studies have identified a large number of putative toxins in the transcriptome of C. cf. simula; however, corresponding proteomic data have so far been lacking. This study presents the first comprehensive analysis of the mucus and proboscis proteome of C. cf. simula using high-performance liquid chromatography-tandem mass spectrometry. We identified three putative toxins in the proboscis and three in the mucus. Additionally, four cysteine-rich peptides with putative toxic activity were identified in the mucus and one in the proboscis. The expression of the corresponding genes in both tissues was quantified using quantitative real-time PCR. The toxin compositions of the proboscis and mucus showed clear signs of functional specialization, with no overlapping toxins and tissue-specific patterns of gene expression. Feeding experiments combined with transmission electron microscopy confirmed the involvement of specialized proboscis structures, pseudocnidae, in delivering toxins into the prey.

Fireflies, which predominantly prey on various mollusks such as small snails and slugs, are renowned for their unique bioluminescence. Firefly toxins-particularly Lucibufagins (LBGs), which target the α-subunit of the sodium-potassium pump protein (ATPα)-play a crucial role in their survival strategies. However, the types and functions of venom proteins in fireflies remain to be elucidated. In this study, transcriptome sequencing was employed on the larval head of Pyrocoelia analis larvae, through which transcripts encoding several putative venom proteins were identified, including phospholipase A1/A2, 5'-nucleotidase, cysteine-rich secretory proteins (CRISPs), and insulin-like peptides. Structural comparison revealed that venom proteins in fireflies exhibited high sequence and structural similarity with venom proteins from various venomous animals (e.g., snakes, scorpions, spiders, and cone snails). These venom proteins may exert synergistic effects through multiple mechanisms, such as neurotoxicity, metabolic interference, and cytotoxicity, thereby playing an essential role in mollusk predation and defense against predators. Our study not only analyzes the complexity and uniqueness of Py. analis venom proteins but also provides a robust foundation for further exploration of the ecological adaptability and evolutionary mechanisms of these venom proteins.

Botulinum neurotoxin serotype A (BoNT/A) is the most potent known neurotoxin. While its light chain (LC) catalytic domain is a prime target for next-generation vaccines and therapeutics, the functional differences among BoNT/A subtype LCs (A1, A2, A3) remain to be definitively characterized, despite notable sequence variation. This work aimed to systematically compare the proteolytic activity and immunoprotective efficacy of recombinant BoNT/A1-LC, A2-LC, and A3-LC. Recombinant A1-LC-His, A2-LC-His, A3-LC-His, and A3-LC-Twin-Strep proteins were expressed in Escherichia coli (E. coli) and purified with affinity chromatography. Their proteolytic activity was assessed via in vitro SNAP-25 cleavage assays. The protective potency of these antigens was evaluated in a mouse model. In vitro cleavage assays revealed a substrate cleavage efficiency order of A2-LC > A1-LC > A3-LC. In vivo, both A1-LC and A2-LC immunization conferred robust, broad protection against high-dose challenges with all three toxin subtypes. In stark contrast, A3-LC provided only minimal protection against its homologous toxin and none against heterologous subtypes. Crucially, the functional deficit of A3-LC was confirmed to be an intrinsic property, as the A3-LC-TS variant, designed to exclude tag-specific interference, exhibited comparable low efficacy. According to structural research, A3-LC's compromised function may be caused by a four-amino-acid loss. The inferior performance of A3-LC is inherent to its primary structure. This work identified A1-LC or A2-LC as the potential proteolytic activity molecule and vaccine antigen by demonstrating functional differences among BoNT/A subtype LCs. These findings provide crucial insights for developing subtype-specific countermeasures against botulism.

Aflatoxins (AFs) are potent hepatotropic mycotoxins-AFB₁ being the best-characterized-yet their ability to induce intrahepatic cholangiocarcinoma (iCCA) remains underexplored. Male Wistar rats received vehicle (controls; n = 5) or an AFB₁-dominant AF mixture (AFB₁ 39.46 μg/mL; AFB₂ 1.13 μg/mL; AFG₁ 17.44 μg/mL; AFG₂ 0.59 μg/mL- n = 10) by daily gavage for 90 days, at a dose equivalent to 400 μg AFB₁ per kg of diet. After 12 months, twelve iCCA tumors were resected and analyzed by histology (H&E) and tissue-microarray-based immunohistochemistry (Cytokeratin-19, Hep Par-1, p53, Cyclin D1, Rb, β-catenin, and PCNA). Lesions predominantly showed glandular/tubular architecture consistent with iCCA and were cytokeratin-19-positive and Hep Par-1-negative. Cell proliferation was high (PCNA ≈ 69%). p53 displayed nuclear accumulation in 83% of tumors. G1/S control was perturbed, with cyclin D1 overexpression (67%), and Rb was positive in 58% of iCCA. Aberrant Wnt activation was rare (nuclear β-catenin in 8%). Subchronic exposure to an AFB₁-dominant AF mixture in rats was associated with iCCA characterized by high proliferative activity, p53 accumulation, and disruption of G1/S checkpoint components. These findings broaden the oncogenic spectrum of AFs and warrant genomic confirmation of AF mutational signatures.

Aflatoxin B₁ (AFB₁), a major metabolite of aflatoxin, is a highly toxic carcinogen. It frequently contaminates feed due to improper storage of feed ingredients such as corn and peanut meal, with the contamination risk further escalating alongside the increasing incorporation of plant-based proteins in feed formulations. Upon entering an organism, AFB₁ is metabolized into highly reactive derivatives, which trigger an oxidative stress-inflammation vicious cycle by binding to biological macromolecules, damaging cellular structures, activating apoptotic and inflammatory pathways, and inhibiting antioxidant systems. This cascade leads to stunted growth, impaired immunity, and multisystem dysfunction in animals. Long-term accumulation can also compromise reproductive function, induce carcinogenesis, and pose risks to human health through residues in the food chain. Tannins are natural polyphenolic compounds widely distributed in plants which exhibit significant antioxidant and anti-inflammatory activities and can effectively mitigate the toxicity of AFB₁. They can repair intestinal damage by increasing the activity of antioxidant enzymes and up-regulating the gene expression of intestinal tight junction proteins, regulate the balance of intestinal flora, and improve intestinal structure. Meanwhile, tannins can activate antioxidant signaling pathways, up-regulate the gene expression of antioxidant enzymes to enhance antioxidant capacity, exert anti-inflammatory effects by regulating inflammation-related signaling pathways, further reduce DNA damage, and decrease cell apoptosis and pyroptosis through such means as down-regulating the expression of pro-apoptotic genes. This review summarizes the main harm of AFB₁ to animals and the mitigating mechanisms of tannins, aiming to provide references for the resource development of tannins and healthy animal farming.

The consumption of nuts is widespread globally and constitutes a significant component of the human diet due to its nutritional value. However, the presence of mycotoxins in food products, including nuts, is a global public health concern. Mycotoxins are toxic metabolites produced by contaminating fungi such as Aspergillus spp. and Penicillium spp., which can contaminate crops during growth, harvesting, storage, or transport. The aim of this study was to conduct monitoring for the presence of mycotoxins in nuts already on the market. Specifically, secondary metabolites produced by Penicillium spp., including ochratoxin A, patulin, citrinin, cyclopiazonic acid, citreoviridin, griseofulvin, meleagrin, mycophenolic acid, penitrem A, roquefortine C, penicillins G and V, sulochrin, andrastin A, asterriquinone, chaetoglobosin A, cyclopenin, cyclopenol, and viridicatin, were investigated. Commercial products were purchased from various retail outlets in different formats, origins, and cultivation methods to assess potential influences of these factors on mycotoxin presence. Regarding Penicillium-toxins, 37% of the samples showed the presence of at least one of them, and 9% showed the simultaneous presence of two or more Penicillium-toxins. Peanuts had the highest incidence of Penicillium-toxin contamination, with at least one metabolite detected in 60% of the analyzed samples. The most common secondary metabolite among the samples was patulin (14%), while the secondary metabolite with the highest concentration was viridicatin in a walnut sample (151.40 ± 64.30 µg/kg). Besides Penicillium-toxins, aflatoxins were also analyzed with another validated LC-MS/MS method, but they were not detected in any sample. Although most Penicillium-toxins, and in particular patulin in nuts, are not currently regulated in the international legislation, they exert toxic effects on humans and animals, and their occurrence can represent a food safety risk.

Accurate quantification of Deoxynovalienol (DON) in wheat is critical for food safety, but current methods suffer from poor reproducibility due to inconsistent operational parameters across the sampling and analysis workflow. To address this issue, this study focused on truck-loaded bulk wheat and conducted a comprehensive analysis covering the entire process from sampling to laboratory testing. By examining parameters at each stage-test portion, laboratory sample, composite sample, and primary sample-and applying the Monte Carlo simple random sampling principle, the variability associated with the full-process parameters for DON detection in wheat was systematically analyzed. The errors introduced at each step were evaluated, leading to the development of a representative measurement procedure for DON in truck-loaded bulk wheat. The results indicate that for truck-loaded bulk wheat, sampling should be conducted using a random distribution method with no fewer than 11 sampling points, each providing a primary sample of at least 500 g. The composite sample should be homogenized three times using a cone-and-quartering divider before subsampling. The laboratory sample should weigh no less than 750 g and be ground to a particle size of 1 mm. After thorough mixing of the ground sample, 5 g should be accurately weighed for analysis. This measurement procedure introduces a total relative error of 12.9%. The proposed protocol for DON detection in truck-loaded wheat offers a practical approach that minimizes error contribution from each parameter while maintaining low economic and time costs, ensuring feasibility for field implementation.

The authors realized there was an error in the original publication [...].

Zearalenone (ZEN) is a thermostable, lipophilic, non-steroidal estrogenic mycotoxin produced by Fusarium spp. that persistently contaminates food and feed. Its strong estrogenic activity and resistance to conventional detoxification strategies pose significant threats to food safety and human and animal health. Conventional physical and chemical degradation methods often compromise nutritional quality and leave toxic residues. Here we report the engineering of a novel Clonostachys rosea lactone hydrolase, Cr2zen, for efficient ZEN degradation in Pichia pastoris under mild conditions. Native Cr2zen exhibited a protein concentration of 0.076 mg/mL, achieving a degradation rate of approximately 17.9% within 30 min, with kinetic parameters of K_m 75.9 µM and V_max 0.482 µmol/L/s at 30 °C and pH 8.0. By integrating signal peptide screening and codon optimization, we identified Ser-Cr2 as the most effective variant, achieving a rapid 81.53% degradation of 10 ppm ZEN under mild conditions. Fed-batch cultivation in a 7.5 L bioreactor resulted in high cell densities of OD₆₀₀ 332.8 for Ser-Cr2 and 310.8 for Oser-Cr2, with extracellular protein concentrations of 0.62 and 0.79 g/L, respectively. The results demonstrate that signal peptide engineering and codon optimization substantially improved the production of lactone hydrolase in P. pastoris. This study establishes a scalable ZEN degradation under mild conditions in P. pastoris and outlines a strategy to integrate protein and process engineering for enhanced enzymatic mycotoxin degradation.

α-Zearalenol (α-ZOL), the primary metabolite of zearalenone (ZEN), is a prevalent mycotoxin in agricultural products (e.g., corn, wheat) and poses health risks due to its toxicity. However, strategies to mitigate its toxicity are needed. Therefore, this study aims to determine whether selected polyphenols (quercetin, baicalin, rosmarinic acid, naringenin) can competitively displace α-ZOL from human serum albumin (HSA) and to clarify the interaction mechanisms. The results showed that competitive interactions between α-ZOL, HSA, and the polyphenols were observed. The polyphenols bound HSA more tightly than α-ZOL (higher K_a) and significantly reduced α-ZOL's K_a, indicating direct competition. Moreover, as evidenced by synchronous fluorescence, the polyphenols altered the microenvironments of tyrosine and tryptophan residues, directly impacting α-ZOL binding. The HPLC-ultrafiltration results revealed that the polyphenols tested competitively displaced α-ZOL from HSA, with the relative potency of quercetin ≈ baicalin > rosmarinic acid > naringenin. Collectively, our competitive binding assays demonstrate that quercetin, baicalin, rosmarinic acid, and naringenin competitively displace α-ZOL from its binding site(s) on HSA. Thus, our study not only suggests a novel mechanism to alleviate the toxicity of ZEN and α-ZOL but also provides a scientific basis for developing dietary interventions against these mycotoxins.