Dongwei Xiong

Aflatoxin B1 (AFB1) is a potent mycotoxin threatening food and feed safety. Here, we report the identification and characterization of a Bacillus safensis-derived multicopper oxidase (BsaMCO) capable of efficient AFB1 detoxification. Recombinant BsaMCO exhibited robust in vitro activity, achieving >78% degradation of AFB1 under 24 h incubation at 37 °C. Optimization experiments revealed that enzyme concentration, pH, temperature, metal ions, and electron acceptors significantly influenced degradation efficiency, defining an operational window suitable for practical applications. LC–MS profiling suggested the presence of transformation products tentatively consistent with oxidative demethylation to aflatoxin P1 (AFP1) and with the formation of AFG2a-like products through subsequent hydration- and oxidation-related transformations. Molecular docking and 100 ns all-atom molecular dynamics (MD) simulations demonstrated stable binding of AFB1 in the T1 copper pocket. Van der Waals and electrostatic interactions, together with a persistent hydrogen bond at Gly323, facilitated single-electron transfer through the intramolecular T2/T3 copper cluster. Principal component and Gibbs free energy analyses confirmed a low-energy, stable conformational ensemble. HepG2 cell assays indicated that BsaMCO-degraded products substantially reduced cytotoxicity and apoptosis compared with native AFB1. Simulated feed experiments further validated enzymatic AFB1 degradation, with approximately 53% reduction after 24 h. Collectively, these findings establish BsaMCO as a safe and effective biocatalyst for AFB1 detoxification, providing mechanistic, structural, and cellular evidence supporting its application in food and feed safety.

Aflatoxin B1 (AFB1) poses a serious threat to global food and feed safety. Laccase-based enzymatic degradation represents a promising green strategy for AFB1 removal; however, its industrial application is severely limited by the rapid thermal inactivation of wild-type enzymes under high-temperature processing conditions (>70 °C). Here, we engineered the thermal stability of a laccase from Bacillus amyloliquefaciens B10 through an integrated strategy combining computational structural biology with semi-rational design. By coupling molecular dynamics (MD) simulations with folding free-energy (ΔΔG) calculations, we identified key flexible regions associated with thermal instability and subsequently implemented iterative saturation mutagenesis. The best single mutant, R196C, retained more than 96% relative activity after heat treatment at 80 °C for 10 min. Further iterative mutational stacking progressively enhanced thermostability: the R90E/R196C double mutant showed 1.25-fold higher activity at 80 °C than R196C, and the R90E/R196C/H54F triple mutant showed a further 1.16-fold increase over the double mutant. The final quadruple mutant, R90E/R196C/H54F/R253I, achieved 86.9% AFB1 degradation at 80 °C after 24 h. High-temperature MD simulations (100 ns at 353.15 K) indicated that the enhanced thermostability was associated with reduced conformational flexibility, lower radius of gyration (Rg) and solvent-accessible surface area (SASA), and a coil-to-β-sheet transition that contributed to stabilization of the protein core. In addition, efficient secretory expression of the engineered enzyme was achieved in Pichia pastoris, reaching 3.0 U/mL, while the crude enzyme maintained more than 70% activity at 80 °C. Collectively, these results provide a practical basis for the rational engineering and scalable production of thermostable biocatalysts for AFB1 detoxification-related applications of AFB1 control, and offer broader insights into the targeted enhancement of thermal stability in industrial enzymes.

Zearalenone (ZEA) is a widely distributed estrogenic mycotoxin that can disrupt intestinal barrier integrity by inducing ferroptosis, thereby posing serious risks to animal health. Curcumin (CUR), as a natural polyphenolic compound with multi-target regulatory properties, has attracted increasing attention for its antioxidative and cytoprotective effects; however, its role in ZEA-induced ferroptosis remains poorly understood. In this study, the protective effects of curcumin (CUR) were evaluated in IPEC-J2 cells by co-treating the cells with zearalenone (ZEA) at its LC₅₀ (75.23 μM) and curcumin (5 or 15 μM) for 24 h. CCK-8 assays showed that CUR significantly (p < 0.05) and highly significantly (p < 0.01) improved cell viability in the 5 μM and 15 μM groups, respectively, compared with ZEA alone. CUR co-treatment significantly (p < 0.01) restored glutathione (GSH) levels, and markedly (p < 0.01) reduced Fe²⁺ accumulation, reactive oxygen species (ROS) production, malondialdehyde (MDA) content, and lipid peroxidation (LPO). Transmission electron microscopy revealed pronounced mitochondrial cristae loss and membrane collapse in ZEA-treated cells, which were visibly alleviated by CUR. At the molecular level, ZEA downregulated GPX4 and SLC7A11 and upregulated ACSL4, FTH1, and p53 (all p < 0.01), whereas these changes were significantly reversed (p < 0.05 or p < 0.01) by CUR. In conclusion, CUR exerts cytoprotective effects against ZEA-induced ferroptosis, likely via modulation of the p53/SLC7A11/GPX4 signaling pathway.

Zinc oxide nanoparticles (ZnO NPs) have attracted significant attention due to their wide-ranging applications in animal production, largely because of their notable biocompatibility, low toxicity, and strong antimicrobial activity. These properties make ZnO NPs a promising substitute for traditional antibiotics. Their application could address the growing concern of antibiotic resistance in livestock industries. This review examines the unique physicochemical characteristics of ZnO NPs, including their nanoscale size and high surface area, which contribute to their biological functionality. Emphasis is placed on green synthesis methods that minimize environmental impact while producing high-quality ZnO NPs. In animal farming, ZnO NPs play a crucial role not only in promoting growth and improving immune responses, but also in enhancing meat and egg quality. Additionally, this review discusses the environmental and safety implications of ZnO NPs, considering their sustainable application potential in future animal production practices, aimed at fostering a more eco-friendly and efficient livestock sector.

Fumonisin B1 (FB1) is an important toxin which poses global concerns in terms of food safety. Curcumin (Cur), a natural polyphenolic compound, has strong antioxidant and anti-inflammatory effects. Meanwhile, the mechanisms underlying the mitigation of FB1-induced toxicity by Cur are not fully understood, limiting its potential application as a novel feed additive to prevent FB1 toxicity. In this study, porcine kidney cells (PK-15) were used as an experimental model, utilizing mRNA and miRNA transcriptome technologies. The results revealed that Cur upregulated miR-1249 and inhibited the target gene Ern1 in the PK-15 cells, thereby suppressing the IRE1/MKK7/JNK/CASPASE3 endoplasmic reticulum (ER) stress pathway and alleviating FB1-induced cell apoptosis. Cell transfection experiments confirmed that Cur effectively attenuated the apoptosis induced by ER stress following transfection with a miR-1249 inhibitor. Similarly, transfection with a miR-1249 mimic alleviated the ER stress and FB1-induced PK-15 cell apoptosis. These findings reveal that Cur mitigates FB1-induced ER stress and significantly reduces apoptotic damage in porcine kidney cells.

Mycotoxins are secondary metabolites produced by specific fungi. More than 400 different mycotoxins are known in the world, and the concentration of these toxins in food and feed often exceeds the acceptable limit, thus causing serious harm to animals and human body. At the same time, modern industrial agriculture will also bring a lot of environmental pollution in the development process, including the increase of heavy metal content, and often the clinical symptoms of low/medium level chronic heavy metal poisoning are not obvious, thus delaying the best treatment opportunity. However, the traditional ways of detoxification cannot completely eliminate the adverse effects of these toxins on the body, and sometimes bring some side effects, so it is essential to find a new type of safe antidote. Trace element selenium is among the essential mineral nutrient elements of human and animal bodies, which can effectively remove excessive free radicals and reactive oxygen species in the body, and has the effects of antioxidant, resisting stress, and improving body immunity. Selenium is common in nature in inorganic selenium and organic selenium. In previous studies, it was found that the use of inorganic selenium (sodium selenite) can play a certain protective role against mycotoxins and heavy metal poisoning. However, while it plays the role of antioxidant, it will also have adverse effects on the body. Therefore, it was found in the latest study that selenium yeast could not only replace the protective effect of sodium selenite on mycotoxins and heavy metal poisoning, but also improve the immunity of the body. Selenium yeast is an organic selenium source with high activity and low toxicity, which is produced by selenium relying on the cell protein structure of growing yeast. It not only has high absorption rate, but also can be stored in the body after meeting the physiological needs of the body for selenium, so as to avoid selenium deficiency again in the short term. However, few of these studies can clearly reveal the protective mechanism of yeast selenium. In this paper, the detoxification mechanism of selenium yeast on mycotoxins and heavy metal poisoning was reviewed, which provided some theoretical support for further understanding of the biological function of selenium yeast and its replacement for inorganic selenium. The conclusions suggest that selenium yeast can effectively alleviate the oxidative damage by regulating different signaling pathways, improving the activity of antioxidant enzymes, reversing the content of inflammatory factors, regulating the protein expression of apoptosis-related genes, and reducing the accumulation of mycotoxins and heavy metals in the body.

Quercetin, as a flavonol compound found in plants, has a variety of biological activities. It is widely present in nature and the human diet, with powerful oxidative properties and biological activities. In this review, the antioxidant mechanism and broad-spectrum antibacterial properties of quercetin are revealed; the intervention effects of quercetin on pesticide poisoning and the pathway of action are investigated; the toxic effects of main mycotoxins on the collection and the detoxification process of quercetin are summarized; whether it is able to reduce the toxicity of mycotoxins is proved; and the harmful effects of heavy metal poisoning on the collection, the prevention, and control of quercetin are evaluated. This review is expected to enrich the understanding of the properties of quercetin and promote its better application in clinical practice.