Occurrence of deoxynivalenol in wheat, Hebei Province, China

Monitoring Fusarium toxins from barley to malt: Targeted inoculation with Fusarium culmorum

Molds of the genus Fusarium infect nearly all types of grain, causing significant yield and quality losses. Many species of this genus produce mycotoxins, which pose significant risks to human and animal health. In beer production, the complex interaction between primary fungal metabolites and secondarily modified mycotoxins in barley, malt, and beer complicates the situation, highlighting the need for effective analytical methods to quickly and accurately monitor these toxins. We developed and validated a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to simultaneously analyze 14 Fusarium toxins, including modified forms (deoxynivalenol (DON), DON-3-glucoside, 3-acetyl-DON, 15-acetyl-DON, nivalenol, fusarenone X, HT-2 toxin, T-2 toxin, the enniatins A, A1, B, B1, beauvericin, and zearalenone) in barley and throughout the malting process. Stable isotope dilution assays (SIDAs) and matrix-matched calibration were used for quantification. A micro-malting setup was established to produce Fusarium-contaminated barley malt under reproducible conditions using targeted inoculation with F. culmorum. Mycotoxins were quantified throughout the malting process and compared to the content of fungal DNA. Further, the impact of various malting parameters was investigated, thus revealing that different malting scenarios exhibited different toxin enrichment patterns. We demonstrated that mycotoxin concentration and the ratio of DON to DON-3-glucoside changed throughout the malting processes, depending on fungal spore concentrations, germination temperature, and malting temperature. The study highlights the complexity of mycotoxin dynamics in malt production and the importance of optimized processing conditions to minimize toxin levels in final malt products.

Development of reusable electrochemiluminescence sensing microchip for detection of vomitoxin

In this work, a reusable DNA sensing microchip was developed for detection of vomitoxin (deoxynivalenol, DON) in sorghum using Cd-based core-shell CdSe@CdS quantum dots (QDs) as promising electrochemiluminescence (ECL) emitter. The size-adjustable aqueous phase CdSe@CdS QDs were prepared through homogeneous method, exhibiting strong cathodic ECL emission with a central wavelength of 520 nm in S2O82- coreactant. And gold nanoparticles-modified iron cobalt cyanide hydrate (Fe-Co-Au) was introduced as an accelerator to amplify the ECL signal. ECL signal was quenched after the formation of a double-stranded (dsDNA) S1-S2 by generating an electron transfer system between the emitter and ferrocene (Fc), which are modified on the aptamer (ssDNA S1) and its complement sequence (ssDNA S2), respectively. When the target DON is presence, the aptamer ssDNA S1 will bind to the DON and trigger the unbinding of double strands DNA and the release of the ssDNA S2, thus the signal can be generated. This approach offers a feasible method for the detection of DON within the range of 1 ng/mL to 200 ng/mL.

A Study of a New Certified Reference Material for Accurate Determination of the Main Fusarium Mycotoxins in Whole-Wheat Flour

Matrix certified reference materials (CRMs) play a critical role in analytical method validation and the assurance of reliable measurement results. A certified reference material (GBW(E)100813) for whole-wheat flour was developed to ensure an accurate and reliable measurement of the main Fusarium mycotoxins (deoxynivalenol (DON), nivalenol (NIV), deoxynivalenol-3-glucoside (DON-3G), and zearalenone (ZEN)). CRM candidates were prepared using sun-drying, grinding, sieving, homogenising, packaging, and gamma irradiation. The final produced CRM was packaged at 50 g per unit and stored at 20 °C. Certification was performed using isotope dilution-liquid chromatography-tandem mass spectrometry. CRM characterization was performed in eight laboratories in accordance with the requirements of ISO Guide 35. The certified values and expanded uncertainties (at a confidence of 95%, k = 2) for DON, NIV, DON-3G, and ZEN were determined to be 0.98 ± 0.12 mg/kg, 1.37 ± 0.20 mg/kg, 242 ± 35 μg/g, and 382 ± 50 μg/g. The CRM was sufficiently homogeneous between and within bottles, and remained stable for up to 12 months at 20 °C and 9 days below 40 °C for transportation. Thus, CRM can be used for quality control and method validation to ensure the accurate and reliable quantification of the main Fusarium mycotoxins in whole-wheat flour.

Fungal and Toxin Contaminants in Cereal Grains and Flours: Systematic Review and Meta-Analysis

Cereal grains serve as the cornerstone of global nutrition, providing a significant portion of humanity's caloric requirements. However, the presence of fungal genera, such Fusarium, Penicillium, Aspergillus, and Alternaria, known for their mycotoxin-producing abilities, presents a significant threat to human health due to the adverse effects of these toxins. The primary objective of this study was to identify the predominant fungal contaminants in cereal grains utilized in breadmaking, as well as in flour and bread. Moreover, a systematic review, including meta-analysis, was conducted on the occurrence and levels of mycotoxins in wheat flour from the years 2013 to 2023. The genera most frequently reported were Fusarium, followed by Penicillium, Aspergillus, and Alternaria. Among the published reports, the majority focused on the analysis of Deoxynivalenol (DON), which garnered twice as many reports compared to those focusing on Aflatoxins, Zearalenone, and Ochratoxin A. The concentration of these toxins, in most cases determined by HPLC-MS/MS or HPLC coupled with a fluorescence detector (FLD), was occasionally observed to exceed the maximum limits established by national and/or international authorities. The prevalence of mycotoxins in flour samples from the European Union (EU) and China, as well as in foods intended for infants, exhibited a significant reduction compared to other commercial flours assessed by a meta-analysis investigation.

Occurrence of Types A and B Trichothecenes in Cereal Products Sold in Romanian Markets

In view of the frequent occurrences of mycotoxins in cereals, this study assessed the presence of trichothecenes in 121 samples from Romanian markets. These samples were divided into five groups based on product type: (1) bread and bakery products containing white flour, (2) half-brown bread with whole wheat flour, (3) brown bread containing rye flour, (4) pasta, and (5) raw wheat. Gas Chromatography-Mass Spectrometry was used to detect 13 different mycotoxins, which included the Type A compounds HT-2 toxin and T-2 toxin, as well as the Type B compounds deoxynivalenol and nivalenol. Results indicated trichothecene contamination in 90.08% of our samples, with deoxynivalenol predominating by at least 78% in each examined group. Co-occurrence of three or four trichothecenes were found in 23.85% of our samples. Our study underscores the necessity of consistent monitoring of staple foods to prevent the intake of harmful trichothecenes by consumers.

Mycotoxin Contamination Status of Cereals in China and Potential Microbial Decontamination Methods

The presence of mycotoxins in cereals can pose a significant health risk to animals and humans. China is one of the countries that is facing cereal contamination by mycotoxins. Treating mycotoxin-contaminated cereals with established physical and chemical methods can lead to negative effects, such as the loss of nutrients, chemical residues, and high energy consumption. Therefore, microbial detoxification techniques are being considered for reducing and treating mycotoxins in cereals. This paper reviews the contamination of aflatoxins, zearalenone, deoxynivalenol, fumonisins, and ochratoxin A in major cereals (rice, wheat, and maize). Our discussion is based on 8700 samples from 30 provincial areas in China between 2005 and 2021. Previous research suggests that the temperature and humidity in the highly contaminated Chinese cereal-growing regions match the growth conditions of potential antagonists. Therefore, this review takes biological detoxification as the starting point and summarizes the methods of microbial detoxification, microbial active substance detoxification, and other microbial inhibition methods for treating contaminated cereals. Furthermore, their respective mechanisms are systematically analyzed, and a series of strategies for combining the above methods with the treatment of contaminated cereals in China are proposed. It is hoped that this review will provide a reference for subsequent solutions to cereal contamination problems and for the development of safer and more efficient methods of biological detoxification.

Type B Trichothecenes in Cereal Grains and Their Products: Recent Advances on Occurrence, Toxicology, Analysis and Post-Harvest Decontamination Strategies

Type B trichothecenes (deoxynivalenol, nivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol) and deoxynivalenol-3-glucoside (DON-3G) are secondary toxic metabolites produced mainly by mycotoxigenic Fusarium fungi and have been recognized as natural contaminants in cereals and cereal-based foods. The latest studies have proven the various negative effects of type B trichothecenes on human health. Due to the widespread occurrence of Fusarium species, contamination by these mycotoxins has become an important aspect for public health and agro-food systems worldwide. Hence, their monitoring and surveillance in various foods have received a significant deal of attention in recent years. In this review, an up-to-date overview of the occurrence profile of major type B trichothecenes and DON-3G in cereal grains and their toxicological implications are outlined. Furthermore, current trends in analytical methodologies for their determination are overviewed. This review also covers the factors affecting the production of these mycotoxins, as well as the management strategies currently employed to mitigate their contamination in foods. Information presented in this review provides good insight into the progress that has been achieved in the last years for monitoring type B trichothecenes and DON-3G, and also would help the researchers in their further investigations on metabolic pathway analysis and toxicological studies of these Fusarium mycotoxins.

An Efficient HPLC-PDA Coupled With Supel™ Tox DON SPE Approach for the Analysis of Deoxynivalenol Contamination in Cereal Grains and Feedstuffs in Jiangxi Province

Deoxynivalenol (DON) was commonly found in grains and feedstuffs, which can cause human chronic diseases. In this study, a quick and reliable method was developed for the determination of DON in grains and feedstuffs in Jiangxi Province market. The sample was extracted with acetonitrile-water (84:16, v/v), then purified by Supel™ Tox DON SPE column, and detected by high-performance liquid chromatography (HPLC). The results showed that the calibration curve of DON showed good linearity in the range of 0.01-10.0 μg/mL, and the correlation coefficient R² = 0.9999. The recovery of DON in the spiked maize sample was 94.8-98.5% by spiking with DON at 0.2 µg/g, 1.0 µg/g, and 2.0 µg/g. The RSD was between 2.5 and 3.3%. This method was used to analyze 120 samples, including 90 grains and 30 feedstuffs, collected from the Jiangxi Province market. The results showed that 81 samples of grains were positive with 90.0% positive rates, and 30 samples of feedstuff were positive with 100% positive rates. Maximum concentration of DON was 0.7 μg/g in oat and 6.9 μg/g in wheat feedstuffs, respectively. Fortunately, the positive samples of grains were safe levels in comparison with National standards for food safety limits of mycotoxins in food (1.0 μg/g), while, the feedstuff of oats was over the Maximum Guideline Level of 16.7% (the Maximum Residue Limit, MRL is 5.0 μg/g). The results of this study about current DON pollution in the grains and feedstuffs on the Jiangxi Province market have not been previously reported.

Microfluidics-Based Time-Resolved Fluorescence Immunoassay for the On-Site Detection of Aflatoxins B1 Zearalenone and Deoxynivalenol in Cereals

The primary pollutants in cereal products are aflatoxins B1 (AFB1), zearalenone (ZEN), and deoxynivalenol (DON). In this study, anti-AFB1 MAb (4C9), anti-ZEN MAb (2A3), and anti-DON MAb (1F10) were developed and used in time-resolved fluorescence immunoassay microfluidics to determine AFB1, ZEN, and DON in agricultural products. The linear range for AFB1, ZEN, and DON were 0.05~2.2 μg/kg, 1.45~375.75 μg/kg, and 11.1~124.2 μg/kg, respectively. In maize, the recoveries of AFB1/ZEN/DON were 92~101%, 102~105%, and 103~108%, respectively. High-performance liquid chromatography and the proposed approach had a good correlation. Time-resolved fluorescence immunoassay microfluidics is a highly efficient and sensitive field detection method for fungal toxins in agricultural products.

Plant defense compound triggers mycotoxin synthesis by regulating H2B ub1 and H3K4 me2/3 deposition

Fusarium graminearum produces the mycotoxin deoxynivalenol (DON) which promotes its expansion during infection on its plant host wheat. Conditional expression of DON production during infection is poorly characterized. Wheat produces the defense compound putrescine, which induces hypertranscription of DON biosynthetic genes (FgTRIs) and subsequently leads to DON accumulation during infection. Further, the regulatory mechanisms of FgTRIs hypertranscription upon putrescine treatment were investigated. The transcription factor FgAreA regulates putrescine-mediated transcription of FgTRIs by facilitating the enrichment of histone H2B monoubiquitination (H2B ub1) and histone 3 lysine 4 di- and trimethylations (H3K4 me2/3) on FgTRIs. Importantly, a DNA-binding domain (bZIP) specifically within the Fusarium H2B ub1 E3 ligase Bre1 othologs is identified, and the binding of this bZIP domain to FgTRIs depends on FgAreA-mediated chromatin rearrangement. Interestingly, H2B ub1 regulates H3K4 me2/3 via the methyltransferase complex COMPASS component FgBre2, which is different from Saccharomyces cerevisiae. Taken together, our findings reveal the molecular mechanisms by which host-generated putrescine induces DON production during F. graminearum infection. Our results also provide a novel insight into the role of putrescine during phytopathogen-host interactions and broaden our knowledge of H2B ub1 biogenesis and crosstalk between H2B ub1 and H3K4 me2/3 in eukaryotes.

Occurrence and Risk Assessment of Dietary Exposure to Deoxynivalenol in Wheat-Based Products Based Different Wheat-Producing Area for the Inhabitants in Shanghai, China

Deoxynivalenol (DON) is one of the major mycotoxins that contaminate cereals. In this study, we determined the DON level in wheat-based products from Chinese five main production areas collected in Shanghai and calculated the daily intake of DON for inhabitants using the point evaluation and the probabilistic evaluation based on Monte Carlo simulation. The results showed the positive rates of DON in the products were higher than 80.0%, with the concentrations ranging from 41.8 to 1110 µg/kg. The estimated mean daily intakes of DON for 7- to 10-year-old children and adults groups were below 1 µg/kg bw/day, the provisional maximum tolerable daily intake (PMTDI) set by the Joint FAO/WHO Expert Committee on Food Additives (JECFA), suggesting no health risks for the consumers. However, the 99th percentiles of dietary DON exposures for children and adults exceeded the PMTDI, indicating adverse health effects might occur if the two groups intake highly contaminated wheat-based products. The potential health risks for the two groups exposed to DON in the wheat-based products from the Middle and Lower Yangtze Valley (MLYV) were higher than those from the other areas in China.

Determination of Deoxynivalenol and Its Derivative in Corn Flour and Wheat Flour Using Automated On-line Solid-Phase Extraction Combined with LC-MS/MS

An automated on-line solid-phase extraction (SPE) combined with LC-MS/MS method was developed for determination of deoxynivalenol (DON), 3-acetyl-DON and 15-acetyl-DON in corn flour and wheat flour samples. The extraction solvent of the samples was injected into the automated on-line SPE system to remove matrix interference. After washing step, the targets were eluted from the SPE cartridge into liquid chromatography (LC) column. Several SPE parameters including injection volume, elution volume and eluting flow rate were assessed and optimized. Method validation was evaluated and good linearity was obtained (R² > 99%) with the limit of detection of 0.1-0.2 μg/kg. Recoveries were evaluated in spiked corn flour and wheat flour samples at three concentrations and the values ranged from 86.5% to 99.7%. The benefit of the present method with automated on-line SPE system is the ability to inject directly pure extracts into LC-MS/MS, offering faster analyses and improving analysis efficiency.

Occurrence of mycotoxins in selected agricultural and commercial products available in eastern Poland

The objective of this study was the estimation of the content of 13 mycotoxins (diacetoxyscirpenol, T-2 toxin, HT-2 toxin, nivalenol, deoxynivalenol, 3-acetyldeoxynivalenol, fusarenone X, aflatoxin B1, aflatoxin B2, aflatoxin G1, aflatoxin G2, ochratoxin A, and zearalenone) in various products from the eastern part of Poland. The content of mycotoxins in the analysed samples was assayed using the extraction method combined with HPLC-MS/MS analysis. We found mycotoxins in 25 of the 92 samples tested (27%). Contamination with mycotoxins was noted most frequently in samples of cereals – 56% – and also in samples of flour and cocoa, in which a content of mycotoxins was noted in 24 and 16% of the samples, respectively. The most frequently identified were the following – deoxynivalenol detected in 18 samples (72%), zearalenone detected in eight samples (32%), toxin HT-2 detected in four samples (16%), ochratoxin A identified in three samples (12%), and toxin T-2 detected in one sample (4%). In one analysed sample of mixed flour and in one analysed sample of wheat and rye flour, the maximum allowable concentration was exceeded in the case of two identified mycotoxins – deoxynivalenol (2,250 μg/kg) and ochratoxin A (15.6 and 17.1 μg/kg).

Endoplasmic Reticulum Adaptation and Autophagic Competence Shape Response to Fluid Shear Stress in T24 Bladder Cancer Cells

Accumulation of xenobiotics and waste metabolites in the urinary bladder is constantly accompanied by shear stress originating from the movement of the luminal fluids. Hence, both chemical and physical cues constantly modulate the cellular response in health and disease. In line, bladder cells have to maintain elevated mechanosensory competence together with chemical stress response adaptation potential. However, much of the molecular mechanisms sustaining this plasticity is currently unknown. Taking this as a starting point, we investigated the response of T24 urinary bladder cancer cells to shear stress comparing morphology to functional performance. T24 cells responded to the shear stress protocol (flow speed of 0.03 ml/min, 3 h) by significantly increasing their surface area. When exposed to deoxynivalenol-3-sulfate (DON-3-Sulf), bladder cells increased this response in a concentration-dependent manner (0.1-1 µM). DON-3-Sulf is a urinary metabolite of a very common food contaminant mycotoxin (deoxynivalenol, DON) and was already described to enhance proliferation of cancer cells. Incubation with DON-3-Sulf also caused the enlargement of the endoplasmic reticulum (ER), decreased the lysosomal movement, and increased the formation of actin stress fibers. Similar remodeling of the endoplasmic reticulum and area spread after shear stress were observed upon incubation with the autophagy activator rapamycin (1-100 nM). Performance of experiments in the presence of chloroquine (chloroquine, 30 μM) further contributed to shed light on the mechanistic link between adaptation to the biomechanical stimulation and ER stress response. At the molecular level, we observed that ER reshaping was linked to actin organization, with the two components mutually regulating each other. Indeed, we identified in the ER stress-cytoskeletal rearrangement an important axis defining the physical/chemical response potential of bladder cells and created a workflow for further investigation of urinary metabolites, food constituents, and contaminants, as well as for pharmacological profiling.

Fusarium graminearum species complex occurrence on soybean and F. graminearum sensu stricto inoculum maintenance on residues in soybean-wheat rotation under field conditions

AIMS

The aims of this study were to determine the occurrence of Fusarium graminearum species complex (FGSC) on soybean pods, seeds and roots, including rhizoplane, during the period of soybean crop in rotation with wheat and to evaluate the FGSC dynamics on wheat and soybean residues during two soybean growing seasons in rotation with wheat, particularly F. graminearum sensu stricto (FGss).

METHODS AND RESULTS

Soybean roots, pods and seeds were analysed during 2012/13 and 2013/14 seasons. The morphological identification of FGSC and mycotoxin analysis was done. Crop residues were taken in both soybean season in wheat rotation and FGss were quantificated by real-time PCR. The results showed that Fusarium species, mainly FGSC, survive in a soybean crop in rotation with wheat. Isolation frequency of these species was higher on soybean pods than on seeds at R6 stage. Deoxynivalenol contamination on soybean seeds was higher in the 2013/14 season in comparison with the 2012/13 season. Low isolation levels of Fusarium species and species that did not belong to FGSC were observed in soybean root, whereas in rhizoplane a higher level was observed. Fusarium species inoculum on residues remained stable during crop succession and the FGSC were recovered from both wheat and soybean residues. Real time PCR data showed a higher DNA concentration of FGss in wheat residues in the first developmental stages of soybean plants, being the levels more significant during 2012/13 season. With regard to soybean residues collected during the wheat growing stages, an increase in DNA from anthesis until wheat harvest was observed.

CONCLUSIONS

In a no-till production system, the populations of FGSC can colonize wheat and soybean residues to become an inoculum source.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study provides new data on the occurrence of FGSC populations in soybean plant and FGss on residues in soybean-wheat rotation, a cultural practice commonly used in in Argentina.

Quinone outside inhibitors affect DON biosynthesis, mitochondrial structure and toxisome formation in Fusarium graminearum

Quinone outside inhibitors (QoIs) are currently extensively used agricultural fungicides. However, the application of QoIs in controlling Fusarium graminearum was rarely reported. No information is available on pharmacological characteristics of QoIs against F. graminearum, as well as their effects on DON biosynthesis. Here, we found that six QoIs exhibited an excellent fungicidal activity against F. graminearum based on mycelial growth and spore germination. ATP production assay further confirmed that QoIs decreased ATP production via inhibiting mitochondrial respiration, which contributes their fungicidal activity. Unfortunately, QoIs can stimulate DON production and up-regulate the expression of Tri5 and Tri6 genes. Additionally, acetyl-CoA, the basic precursor of DON biosynthesis, significantly increased as affected by QoIs, furtherly indicating that QoIs indeed enhance DON biosynthesis. We also found that QoIs can accelerate the formation of toxisomes and enhance the fluorescence signals of Tri-GFP labeled toxisomes, which may be due to the effect of QoIs on toxisome-related endoplasmic reticulum-remodeling. In addition, QoIs could disrupt the homeostasis of mitochondrial dynamics, resulting in the fragmented mitochondria. Finally, the simulated inoculation assay with wheat grains further verified that QoIs can stimulate DON production relative to wheat grain weight, especially relative to mycelial biomass.

Assessment of Deoxynivalenol in Wheat, Corn and Its Products and Estimation of Dietary Intake

The main goal of the present research was to explore the seasonal variation of deoxynivalenol (DON) in wheat, corn, and their products, collected during 2018-2019. Samples of 449 of wheat and products and 270 samples of corn and their products were examined using reverse-phase liquid chromatography with a UV detector. The findings of the present work showed that 104 (44.8%) samples of wheat and products from the summer season, and 91 (41.9%) samples from winter season were contaminated with DON (concentration limit of detections (LOD) to 2145 µg/kg and LOD to 2050 µg/kg), from summer and winter seasons, respectively. In corn and products, 87 (61.2%) samples from summer and 57 (44.5%) samples from winter season were polluted with DON with levels ranging from LOD to 2967 µg/kg and LOD to 2490 µg/kg, from the summer and winter season, respectively. The highest dietary intake of DON was determined in wheat flour 8.84 µg/kg body weight/day from the summer season, and 7.21 µg/kg body weight/day from the winter season. The findings of the work argued the need to implement stringent guidelines and create awareness among farmers, stakeholders, and traders of the harmful effect of DON. It is mostly observed that cereal crops are transported and stockpiled in jute bags, which may absorb moisture from the environment and produce favorable conditions for fungal growth. Therefore, these crops must store in polyethylene bags during transportation and storage, and moisture should be controlled. It is highly desirable to use those varieties that are more resistant to fungi attack. Humidity and moisture levels need to be controlled during storage and transportation.

Two-way immune effects of deoxynivalenol in weaned piglets and porcine alveolar macrophages: Due mainly to its exposure dosage

Mycotoxins are toxic metabolites produced by fungal species that occur frequently in cereals and animal forages throughout the world, posing a serious threat to humans and animals. Although some studies showed the immunotoxicity of mycotoxins, little research focused on the two-way effects of mycotoxins on immune response in vitro and vivo. Here, we explored the effects of deoxynivalenol (DON), one of the most widely distributed mycotoxins, on immune function of piglets and porcine alveolar macrophages (PAMs), and found it exhibited bidirectional immune effects due to different exposure doses. Our results revealed that low doses of DON increased the expressions of TNF-α and IL-6 in piglets and PAMs, promoted the chemotaxis and phagocytosis of PAMs and transformed macrophages to M1 phenotype (P < 0.05). Conversely, high doses of DON increased the expressions of TGF-β and IL-10 in piglets and PAMs, inhibited the chemotaxis and phagocytosis of PAMs and induced macrophages M2-type polarization (P < 0.05). Mechanistically, DON exposure significantly activated the TLR4/NFκB pathway at low doses and induced mitophagy-mediated mitochondrial dysfunction at high doses in vitro and vivo. TLR4 interference and mitophagy activator, CCCP, were used to further confirm their roles. Therefore, we concluded that DON exposure at low doses caused immunostimulation via activating TLR4/NFκB, whereas it was immunoinhibitory at high doses through blocking mitophagy. Our study suggested that both high and low doses mycotoxins contamination might be harmful, and further back up the necessity to take a vigilant attitude to minimize humans and animals intake of mycotoxins in the environment.

Natural Occurrence of Deoxynivalenol and Its Acetylated Derivatives in Chinese Maize and Wheat Collected in 2017

Deoxynivalenol (DON), along with 3-acetyl-deoxynivalenol (3-ADON) and 15-acetyl-deoxynivalenol (15-ADON), occur in grains and cereal products and is often hazardous to humans and livestock. In this study, 579 wheat samples and 606 maize samples intended for consumption were collected from China in 2017 and analyzed to determine the co-occurrence of type-B trichothecenes (DON, 3-ADON, and 15-ADON). All the wheat samples tested positive for DON, while 99.83% of the maize samples were DON-positive with mean DON concentrations of 165.87 and 175.30 μg/kg, respectively. Per the Chinese standard limits for DON, 3.63% of wheat and 2.97% of the maize samples were above the maximum limit of 1000 μg/kg. The DON derivatives (3-ADON and 15-ADON) were less frequently found and were present at lower levels than DON in wheat. 3-ADON and 15-ADON had incidences of 13.53% and 76.40%, respectively, in maize. By analyzing the distribution ratio of DON and its derivatives in wheat and maize, DON (95.51%) was the predominant toxin detected in wheat samples, followed by 3.97% for the combination of DON + 3-ADON, while DON + 3-ADON + 15-ADON and DON + 15-ADON were only found in 0.17% and 0.35% of wheat samples, respectively. Additionally, a large amount of the maize samples were contaminated with DON + 15-ADON (64.19%) and DON (22.11%). The samples with a combination of DON + 3-ADON and DON + 3-ADON + 15-ADON accounted for 1.32% and 12.21%, respectively. Only one maize sample did not contain all three mycotoxins. Our study shows the necessity of raising awareness of the co-occurrence of mycotoxin contamination in grains from China to protect consumers from the risk of exposure to DON and its derivatives.

Deoxynivalenol-Induced Cytotoxicity and Apoptosis in IPEC-J2 Cells Through the Activation of Autophagy by Inhibiting PI3K-AKT-mTOR Signaling Pathway

With the purpose to explore the relationship between deoxynivalenol (DON)-induced apoptosis and autophagy and provide mechanistic explanations for the toxic effects of DON on IPEC-J2 cells, we determined the cell viability, cell morphology, apoptosis, and autophagy by using autophagy inhibitor 3-methyladenine (3-MA), PI3K pathway inhibitor LY294002, and activator 740Y-P. It turned out that 3-MA was able to attenuate the reduction of cell viability induced by DON. Moreover, 3-MA was capable of upregulating the expression of DON-induced autophagic protein p62 and downregulating the expressions of DON-induced autophagic protein LC3-II and apoptotic protein Bax, suggesting that autophagy is a driving mechanism for this apoptotic induction. The results of Annexin V-FITC/PI double staining indicated that DON could induce apoptosis by inhibiting the PI3K-AKT-mTOR signaling pathway. Subsequently, it was further confirmed by Western blot analysis that DON significantly decreased expressions of P-AKT/AKT, p-mTOR/mTOR, and autophagic protein p62, and increased expression of autophagy-related protein LC3-II, suggesting that DON triggered autophagy by inhibiting the PI3K-AKT-mTOR signaling pathway. To conclude, these data reveal that DON may induce cytotoxicity and apoptosis through the activation of autophagy by suppressing the PI3K-AKT-mTOR signaling pathway. This study provides new insights into the mechanisms by which DON incurs cytotoxic effects.

Deoxynivalenol induced apoptosis and inflammation of IPEC-J2 cells by promoting ROS production

Deoxynivalenol (DON) frequently detected in a wide range of foods and feeds, inducing cytotoxicity to animals and humans. To investigate the underlying mechanism of DON-induced apoptosis and inflammation in porcine small intestinal epithelium, intestinal porcine epithelial cells (IPEC-J2 cells) were chosen as objects, and were treated by different concentrations (0 μg/mL, 0.2 μg/mL, 0.5 μg/mL, 1.0 μg/mL, 2.0 μg/mL, 4.0 μg/mL, 6.0 μg/mL) of DON. The results showed that DON induced cytotoxicity of IPEC-J2 cells in a dose-dependent manner, which is demonstrated by decreasing cell viability. Compared with the control group, DON treatment increased the expressions of genes associated with inflammation and apoptosis, such as interleukin-1 beta (IL-1β), cyclooxgenase-2 (COX-2), interleukin-6 (IL-6), tumour necrosis factor-alpha (TNF-α), caspase-3, caspase-8, caspase-9, and decreased the cell anti-oxidative status. Protein immunofluorescence showed increased expression of caspase-3, nuclear factor kB (NF-κB) and phosphorylated NF-κB in IPEC-J2 cells. DON increased the content of intracellular reactive oxygen species (ROS) of IPEC-J2 cells. N-Acetyl-L-cysteine (NAC), a commonly used antioxidant, blocked DON-induced ROS generation, alleviated the DON-induced apoptosis and inflammation. These results suggested that DON-induced impairment of IPEC-J2 cells is possibly due to increased ROS production, and expressions of genes and proteins associated with apoptosis and inflammation.

Fusarium Toxins in Chinese Wheat since the 1980s

Wheat Fusarium head blight (FHB), caused by Fusarium species, is a widespread and destructive fungal disease. In addition to the substantial yield and revenue losses, diseased grains are often contaminated with Fusarium mycotoxins, making them unsuitable for human consumption or use as animal feed. As a vital food and feed ingredient in China, the quality and safety of wheat and its products have gained growing attention from consumers, producers, scientists, and policymakers. This review supplies detailed data about the occurrence of Fusarium toxins and related intoxications from the 1980s to the present. Despite the serious situation of toxin contamination in wheat, the concentration of toxins in flour is usually lower than that in raw materials, and food-poisoning incidents have been considerably reduced. Much work has been conducted on every phase of toxin production and wheat circulation by scientific researchers. Regulations for maximum contamination limits have been established in recent years and play a substantial role in ensuring the stability of the national economy and people's livelihoods.

Mycotoxins' evaluation in wheat flours used in Brazilian bakeries

Abstract

The aim of this study was to evaluate the mycotoxicological quality of wheat flours used by bakeries from the North Region in Rio Grande do Sul state, Brazil, regarding the presence of mycotoxins. On collecting type-1 refined wheat flour, a conglomerate sampling from 13 cities and 3 bakeries per city (n = 39), selected from the defined region was performed. The mycotoxins analysis was using QuEChERS method and UPLC-MS/MS analysis. As a result, 100% of samples presented contamination by DON, with concentrations ranging from 76.7 to 3630.2 µg kg^-1 and ZON was found in one sample (26.7 µg kg^-1), which represented 2.6% of the analyzed wheat flours. Other mycotoxins (AFB1, AFB2, AFG1, AFG2, DAS, HT-2 toxin, OTA, FB1 and FB2) were not detected in the analyzed samples.

Graphical abstract

Assessment of mycotoxin contamination in maize and wheat stored in silos using two sampling processes

Mycotoxin contamination of stored cereals often occurs in a highly heterogeneous manner, necessitating the use of representative sampling to minimise analytical errors. The objective of this study was to compare mycotoxin analysis in stored maize and wheat using two sampling processes. Samples were obtained from four maize silos and two wheat silos. A pneumatic probe was introduced in the centre and at the four central points of each quadrant, from the top to the bottom of the silo (12 m). For sampling process A, this was divided into three samples (upper third, middle third and lower third of the silo height). No sample subdivision took place for sampling process B. LC-MS/MS was used for analysis of aflatoxins (AF), fumonisins (FB), zearalenone (ZEA) and deoxynivalenol (DON) in maize and DON and ZEA in wheat. Sampling procedures were compared with respect to the variability of the collected data. AF, FB, ZEA and DON were detected in 77.5, 100.0, 56.7 and 0.0% of the maize samples, respectively, and the mean concentration differed significantly between silos. In wheat, 100.0 and 97.5% of the samples were contaminated with DON and ZEA, respectively, and there was no significantly difference in mean concentration between silos. There was no significant difference (P>0.05) in the coefficients of variation (CVs) of AF (54.9 and 58.6%), FB (19.4 and 27.3%) and ZEA (68.9 and 85.5%) between sampling processes A and B in maize silos. The DON CV in sampling process A (10.1%) was lower (P<0.05) than the CV in sampling process B (22.2%) in wheat silos. Overall, the two sampling processes provided analytical results with the same variability in maize and different variability for DON in wheat, where process A yielded results with lower variability.

The fungal myosin I is essential for Fusarium toxisome formation

Myosin-I molecular motors are proposed to function as linkers between membranes and the actin cytoskeleton in several cellular processes, but their role in the biosynthesis of fungal secondary metabolites remain elusive. Here, we found that the myosin I of Fusarium graminearum (FgMyo1), the causal agent of Fusarium head blight, plays critical roles in mycotoxin biosynthesis. Inhibition of myosin I by the small molecule phenamacril leads to marked reduction in deoxynivalenol (DON) biosynthesis. FgMyo1 also governs translation of the DON biosynthetic enzyme Tri1 by interacting with the ribosome-associated protein FgAsc1. Disruption of the ATPase activity of FgMyo1 either by the mutation E420K, down-regulation of FgMyo1 expression or deletion of FgAsc1 results in reduced Tri1 translation. The DON biosynthetic enzymes Tri1 and Tri4 are mainly localized to subcellular structures known as toxisomes in response to mycotoxin induction and the FgMyo1-interacting protein, actin, participates in toxisome formation. The actin polymerization disruptor latrunculin A inhibits toxisome assembly. Consistent with this observation, deletion of the actin-associated proteins FgPrk1 and FgEnd3 also results in reduced toxisome formation. Unexpectedly, the FgMyo1-actin cytoskeleton is not involved in biosynthesis of another secondary metabolite tested. Taken together, this study uncovers a novel function of myosin I in regulating mycotoxin biosynthesis in filamentous fungi.

The mycotoxin deoxynivalenol (DON) is the most frequently detected secondary metabolite produced by Fusarium graminearum and other Fusarium spp. To date, relatively few studies have addressed how mycotoxin biosynthesis occurs in fungal cells. Here we found that myosin I governs translation of DON biosynthetic enzyme Tri1 via interacting with the ribosome-associated protein FgAsc1. Moreover, the key DON biosynthetic enzymes Tri1 and Tri4 are mainly localized to the toxisomes derived from endoplasmic reticulum under toxin inducing conditions. We further found that the FgMyo1-actin cytoskeleton was involved in toxisome formation but not for the biosynthesis of another secondary metabolite tested. Taken together, these results indicate for the first time that myosin I plays critical roles in mycotoxin biosynthesis.

Occurrence and risk assessment of population exposed to deoxynivalenol in foods derived from wheat flour in Brazil

Deoxynivalenol (DON) is the most important of the trichothecenes in terms of amounts and occurrence in wheat. This compound was shown to be associated with a glomerulonephropathy involving an increase of immunoglobulin A in humans. This study assessed the occurrence of DON in wheat flour and the exposure of Brazilian teenagers, adults and elderly to this mycotoxin due to intake of wheat flour-based products. DON extraction in wheat flour was carried out by solid phase extraction and the quantification was performed by ultra-high proficiency liquid chromatography with diode-array detection. A total of 77.9% of all samples were positive for DON, with concentrations ranging from 73.50 to 2794.63 µg kg^-1. The intake was calculated for the average and 90th percentile of the contamination levels of DON in foods based-wheat for teenagers, adults and elderly in Brazil, and compared with the provisional maximum tolerable daily intakes (PMTDI). Females of all age groups were exposed to DON at higher levels when compared to males in regard of consumption of breads and pastas. Teenagers were the main consumers of foods derived from wheat flour, with maximum probable daily intakes of 1.28 and 1.20 µg kg^-1 b.w. day^-1 for females and males, respectively. This population is at an increased risk of exposure to DON due to consumption of wheat flour-based foods in Brazil.

Deoxynivalenol and its acetyl derivatives in bread and biscuits in Shandong province of China

In the present study, 100 commercial breads and biscuits were investigated for the occurrence of deoxynivalenol (DON) and its acetylated derivatives 3-acetyldeoxynivalenol (3-Ac-DON) and 15-acetyldeoxynivalenol (15-Ac-DON). The target mycotoxins were determined by isotope dilution ultrahigh performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). DON was determined in 95% of the test samples with a mean value of 153.3 µg/kg. Compared with DON, 3-Ac-DON and 15-Ac-DON were far less frequently detected, with mean values of 1.14 and 0.37 µg/kg, respectively. The estimated daily intakes of the sum of DON and its derivatives in breads and biscuits were 0.0059 and 0.0313 µg/kg bw/day, respectively, which was within the group provisional tolerable daily intake of 1.0 µg/kg bw/day set by the Joint FAO/WHO Expert Committee on Food Additives. In the future, systematic monitoring programmes of DON and its derivatives in relevant foodstuffs are still necessary for food safety and human health.

Analytical techniques for deoxynivalenol detection and quantification in wheat destined for the manufacture of commercial products

The concern regarding toxicity from the presence of deoxynivalenol (DON) in wheat that affects both economy and public health leads to the need to find appropriate detection methods for determining the degree of DON contamination in terms of the equipment available and the speed required for obtaining the incidence. The objective of this study was to compare the performance of two alternative analytical techniques for DON quantification for use in the food industry with a reference technique. Samples of wheat and the commercial by-products were analysed by high-performance liquid chromatography (HPLC) with an ultraviolet detector as the reference method and the results compared with those obtained from a rapid lateral-flow immunochromatographic device (Reveal Q+) and of a Fourier-transform-infrared (FTIR) spectroscopy technique. Pearson’s correlation coefficient between the HPLC and Reveal-Q+ data (0.45), although significant (P<0.0003), was lower than that obtained between HPLC and the FTIR method (0.94, P<0.0001). Both methods were considered efficient in quantifying DON levels in wheat-flour samples. This study was aimed at assisting the producers in choosing an appropriate tool for the purpose of analysis and upon consideration of the available equipment.

Phosphoproteome Analysis Reveals the Molecular Mechanisms Underlying Deoxynivalenol-Induced Intestinal Toxicity in IPEC-J2 Cells

Deoxynivalenol (DON) is a widespread trichothecene mycotoxin that commonly contaminates cereal crops and has various toxic effects in animals and humans. DON primarily targets the gastrointestinal tract, the first barrier against ingested food contaminants. In this study, an isobaric tag for relative and absolute quantitation (iTRAQ)-based phosphoproteomic approach was employed to elucidate the molecular mechanisms underlying DON-mediated intestinal toxicity in porcine epithelial cells (IPEC-J2) exposed to 20 μM DON for 60 min. There were 4153 unique phosphopeptides, representing 389 phosphorylation sites, detected in 1821 phosphoproteins. We found that 289 phosphopeptides corresponding to 255 phosphoproteins were differentially phosphorylated in response to DON. Comprehensive Gene Ontology (GO) analysis combined with Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment revealed that, in addition to previously well-characterized mitogen-activated protein kinase (MAPK) signaling, DON exposure altered phosphatidylinositol 3-kinase/Akt (PI3K/Akt) and Janus kinase/signal transducer, and activator of transcription (JAK/STAT) pathways. These pathways are involved in a wide range of biological processes, including apoptosis, the intestinal barrier, intestinal inflammation, and the intestinal absorption of glucose. DON-induced changes are likely to contribute to the intestinal dysfunction. Overall, identification of relevant signaling pathways yielded new insights into the molecular mechanisms underlying DON-induced intestinal toxicity, and might help in the development of improved mechanism-based risk assessments in animals and humans.

Fusarium Toxins in Cereals: Occurrence, Legislation, Factors Promoting the Appearance and Their Management

Fusarium diseases of small grain cereals and maize cause significant yield losses worldwide. Fusarium infections result in reduced grain yield and contamination with mycotoxins, some of which have a notable impact on human and animal health. Regulations on maximum limits have been established in various countries to protect consumers from the harmful effects of these mycotoxins. Several factors are involved in Fusarium disease and mycotoxin occurrence and among them environmental factors and the agronomic practices have been shown to deeply affect mycotoxin contamination in the field. In the present review particular emphasis will be placed on how environmental conditions and stress factors for the crops can affect Fusarium infection and mycotoxin production, with the aim to provide useful knowledge to develop strategies to prevent mycotoxin accumulation in cereals.