Fusarium Mycotoxins Deoxynivalenol Research Articles

Mycotoxin contamination in organic and conventional cereal grain and products: A systematic literature review and meta-analysis.

There is still considerable controversy about the relative risk of mycotoxin exposure associated with the consumption of organic and conventional cereals. Using validated protocols, we carried out a systematic literature review and meta-analyses of data on the incidence and concentrations of mycotoxins produced by Fusarium, Claviceps, Penicillium, and Aspergillus species in organic and conventional cereal grains/products. The standard weighted meta-analysis of concentration data detected a significant effect of production system (organic vs. conventional) only for the Fusarium mycotoxins deoxynivalenol, with concentrations ∼50% higher in conventional than organic cereal grains/products (p<0.0001). Weighted meta-analyses of incidence data and unweighted meta-analyses of concentration data also detected small, but significant effects of production system on the incidence and/or concentrations of T-2/HT-2 toxins, zearalenone, enniatin, beauvericin, ochratoxin A (OTA), and aflatoxins. Multilevel meta-analyses identified climatic conditions, cereal species, study type, and analytical methods used as important confounding factors for the effects of production system. Overall, results from this study suggest that (i) Fusarium mycotoxin contamination decreased between the 1990s and 2020, (ii) contamination levels are similar in organic and conventional cereals used for human consumption, and (iii) maintaining OTA concentrations below the maximum contamination levels (3.0μg/kg) set by the EU remains a major challenge.

Real-life exposure to Fusarium toxins deoxynivalenol and zearalenone triggers apoptosis and activates NLRP3 inflammasome in bovine primary theca cells.

Cattle are deemed less susceptible to mycotoxins due to the limited internal exposure resulting from rumen microbiota activity. However, the significant amounts of Fusarium mycotoxins deoxynivalenol (DON) and zearalenone (ZEN) frequently detected in bovine follicular fluid samples suggest that they could affect ovarian function. Both mycotoxins trigger several patterns of cell death and activate the NLRP3 inflammasome in the intestine. In vitro studies have reported a number of adverse effects on bovine oocytes. However, the biological relevance of such findings with regard to realistic concentrations of DON and ZEN in bovine follicular fluid is still not clear. Hence, it is important to better characterize the effects of dietary exposure to DON and ZEN on the bovine ovary. Using bovine primary theca cells, this study investigated the effects of real-life patterns for bovine ovary exposure to DON and ZEN, but also DON metabolite DOM-1, on cell death and NLRP3 inflammasome activation. Exposure to DON starting from 0.1μM significantly decreased theca cell viability. The kinetics of phosphatidylserine translocation and loss of membrane integrity showed that ZEN and DON, but not DOM-1, induce an apoptotic phenotype. qPCR analysis of the expression of NLRP3, PYCARD, IL-1β, IL-18, and GSDMD in primary theca cells at concentrations of mycotoxin previously reported in cow follicular fluid clearly indicated that DON and DOM-1 individually and in mixture, but not ZEN, activate NLRP3 inflammasome. Altogether, these results suggest that real-life dietary exposure of cattle to DON may induce inflammatory disorders in the ovary.

Efficacy of Different Fungicide Spraying Techniques on the Infestation with Kabatiella zeae and Formation of Fusarium Mycotoxins in Forage Maize

The application of fungicides in maize by the commonly used overhead spraying technique is more challenging than in small-grain cereals. Especially in later development stages, when the plant has reached a considerable height, lower plant organs (e.g., ears) may be insufficiently protected, since a large part of the applied fungicide is deposited on the upper leaves. In contrast, lower plant organs can be reached by the dropleg spraying technique, which allows sub-canopy applications. This study investigated the efficacy of fungicide applications during flowering in forage maize using the overhead and dropleg spraying techniques as well as a combination for the control of Kabatiella zeae and mycotoxin-producing Fusarium species, which can affect leaves and ears, respectively. The efficacy was evaluated in field trials under natural K. zeae and artificial Fusarium inoculum conditions in Northern Germany by measuring disease severities of K. zeae on maize leaves, dry matter yields, and concentrations of the Fusarium mycotoxins deoxynivalenol (DON) and zearalenone (ZEN) at harvest. Fusarium inoculations of main ears at full flowering resulted in significantly higher DON and ZEN concentrations compared to natural Fusarium infections, whereas the dry matter yield was not affected. The strongest disease progressions of K. zeae were determined after flowering on the upper leaves and leaves around the main ear. Disease severities were significantly reduced on the upper leaves by the overhead application and the combination of the overhead and dropleg spraying technique, whereby the three spraying techniques were equally able to decrease the infestation on the yield-essential leaves around the main ear. No differences in dry matter yield were found between the application techniques, but they were significantly higher than in the untreated control. The contamination with DON and ZEN was most effectively reduced by sub-canopy applications using the dropleg technique, whether as a solo application or in combination with the overhead technique. The main ears were reached better with the applied fungicide, reducing Fusarium infections, and therefore, contamination with mycotoxins. The dropleg technique offers an opportunity for improved protection of lower plant organs, especially in tall growing crops. In combination with the overhead spraying technique, the protection of various plant organs along the entire plant with the applied fungicide could be advantageous, especially when different parts of the plant are affected by different fungal diseases.

Fusarium Mycotoxins Zearalenone and Deoxynivalenol Reduce Hepatocyte Innate Immune Response after the Listeria monocytogenes Infection by Inhibiting the TLR2/NFκB Signaling Pathway.

Zearalenone (ZEA) and deoxynivalenol (DON) are two common mycotoxins produced by the genus Fusarium and have potential immunotoxic effects that may lead to a weak immune response against bacterial infections. Listeria monocytogenes (L. monocytogenes), a food-borne pathogenic microorganism ubiquitous in the environment, actively multiplies in the liver, where hepatocytes are capable of resistance through mediated innate immune responses. At present, it is not clear if ZEA and DON affect hepatocyte immune responses to L. monocytogenes infection or the mechanisms involved. Therefore, in this study, in vivo and in vitro models were used to investigate the effects of ZEA and DON on the innate immune responses of hepatocytes and related molecules after L. monocytogenes infection. In vivo studies revealed that ZEA and DON inhibited the toll-like receptors 2 (TLR2)/nuclear factor kappa-B (NFκB) pathway in the liver tissue of L. monocytogenes-infected mice, downregulating the expression levels of Nitric oxide (NO), in the liver and repressing the immune response. In addition, ZEA and DON inhibited Lipoteichoic acid (LTA)-induced expression of TLR2 and myeloid differentiation factor 88 (MyD88) in Buffalo Rat Liver (BRL 3A) cells in vitro, downregulating the TLR2/NFκB signaling pathway and resulting in the decreased expression levels of NO, causing immunosuppressive effects. In summary, ZEA and DON can negatively regulate NO levels through TLR2/NFκB, inhibiting the innate immune responses of the liver, and aggravate L. monocytogenes infections in mouse livers.

Influence of deoxynivalenol-contaminated feed on the immune response of pigs after PRRSV vaccination and infection

The impact of the Fusarium mycotoxin deoxynivalenol (DON) on the immune response against porcine reproductive and respiratory syndrome virus (PRRSV) vaccination and infection was investigated. Forty-two weaned piglets were separated into seven groups and received three different diets: Low DON (1.09 ppm), High DON (2.81 ppm) or No DON. These three treatments were split further into either vaccinated (Ingelvac PRRSFLEX EU) and challenged with PRRSV 28 days post-vaccination, or only infected at day 28. A seventh group received no DON, no vaccination, and no infection. Two weeks after challenge infection, when pigs were euthanized, the number of IFN-γ producing lymphocytes in the blood of vaccinated animals was lower in pigs on High DON compared to animals on Low DON or No DON. Intracellular cytokine staining showed that vaccinated animals fed with the Low DON diet had higher frequencies of TNF-α/IFN-γ co-producing CD4+ T cells than the other two vaccinated groups, particularly in lung tissue. Vaccinated animals on High DON had similar viral loads in the lung as the non-vaccinated groups, but several animals of the Low DON or No DON group receiving vaccination had reduced titers. In these two groups, there was a negative correlation between lung virus titers and vaccine-specific TNF-α/IFN-γ co-producing CD4+ T cells located either in lung tissue or blood. These results indicate that after PRRSV vaccination and infection, high levels of DON negatively influence immune parameters and clearance of the virus, whereas low DON concentrations have immunomodulatory effects.

Identification of a UDP-glucosyltransferase conferring deoxynivalenol resistance in Aegilops tauschii and wheat.

Aegilops tauschii is the diploid progenitor of the wheat D subgenome and a valuable resource for wheat breeding, yet, genetic analysis of resistance against Fusarium head blight (FHB) and the major Fusarium mycotoxin deoxynivalenol (DON) is lacking. We treated a panel of 147 Ae. tauschii accessions with either Fusarium graminearum spores or DON solution and recorded the associated disease spread or toxin-induced bleaching. A k-mer-based association mapping pipeline dissected the genetic basis of resistance and identified candidate genes. After DON infiltration nine accessions revealed severe bleaching symptoms concomitant with lower conversion rates of DON into the non-toxic DON-3-O-glucoside. We identified the gene AET5Gv20385300 on chromosome 5D encoding a uridine diphosphate (UDP)-glucosyltransferase (UGT) as the causal variant and the mutant allele resulting in a truncated protein was only found in the nine susceptible accessions. This UGT is also polymorphic in hexaploid wheat and when expressed in Saccharomyces cerevisiae only the full-length gene conferred resistance against DON. Analysing the D subgenome helped to elucidate the genetic control of FHB resistance and identified a UGT involved in DON detoxification in Ae. tauschii and hexaploid wheat. This resistance mechanism is highly conserved since the UGT is orthologous to the barley UGT HvUGT13248 indicating descent from a common ancestor of wheat and barley.

Exploration of Mycotoxin Accumulation and Transcriptomes of Different Wheat Cultivars during Fusarium graminearum Infection.

Fusarium graminearum is one of the most devastating diseases of wheat worldwide, and can cause Fusarium head blight (FHB). F. graminearum infection and mycotoxin production mainly present in wheat and can be influenced by environmental factors and wheat cultivars. The objectives of this study were to examine the effect of wheat cultivars and interacting conditions of temperature and water activity (aw) on mycotoxin production by two strains of F. graminearum and investigate the response mechanisms of different wheat cultivars to F. graminearum infection. In this regard, six cultivars of wheat spikes under field conditions and three cultivars of post-harvest wheat grains under three different temperature conditions combined with five water activity (aw) conditions were used for F. graminearum infection in our studies. Liquid chromatography tandem mass spectrometry (LC–MS/MS) analysis showed significant differences in the concentration of Fusarium mycotoxins deoxynivalenol (DON) and its derivative deoxynivalenol-3-glucoside (D3G) resulting from wheat cultivars and environmental factors. Transcriptome profiles of wheat infected with F. graminearum revealed the lower expression of disease defense-factor-related genes, such as mitogen-activated protein kinases (MAPK)-encoding genes and hypersensitivity response (HR)-related genes of infected Annong 0711 grains compared with infected Sumai 3 grains. These findings demonstrated the optimal temperature and air humidity resulting in mycotoxin accumulation, which will be beneficial in determining the conditions of the relative level of risk of contamination with FHB and mycotoxins. More importantly, our transcriptome profiling illustrated differences at the molecular level between wheat cultivars with different FHB resistances, which will lay the foundation for further research on mycotoxin biosynthesis of F. graminearum and regulatory mechanisms of wheat to F. graminearum.

Natural contamination of Czech malting barley with mycotoxins in connection with climate variability

Ongoing climate change is affecting the geographical distribution of microscopic filamentous fungi and the mycotoxins they produce. In 2018–2020, the occurrence of the Fusarium mycotoxins deoxynivalenol, zearalenone, the sum of T-2 and HT-2 toxin, and ochratoxin A was monitored in a total of 450 samples of spring and winter malting barley from different regions of the Czech Republic. On average, the total contents of positive samples in the respective years were 40% for DON, 21% for ZEN and almost 79% for the sum of T-2, and HT-2 toxins. The ochratoxin A content was always below the detection limit except for three samples from the 2019 harvest. Mycotoxin levels were strongly affected by climate variability in the respective years. Very low concentrations of DON and ZEN were found in 2018–2019 with low rainfall and high temperatures. The highest level of contamination was found in the 2020 harvest, with 3.7% of samples exceeding the maximum level for DON and 2.2% for ZEN. The T-2 and HT-2 toxin levels increased year on year. This increasing contamination with T-2 and HT-2 toxins may indicate a change in the spectrum of fungal pathogens and their adaptation to new conditions.

Cytotoxicity of the Fusarium mycotoxin deoxynivalenol on mammalian and avian cell lines

Trichothecenes are mycotoxins that occur in grains and can lead to acute and chronic poisoning in animals and humans. Deoxynivalenol (DON) is a type B trichothecene affecting protein synthesis, immune system, leading to brain, blood and kidney disorders. The aim of this work was to evaluate in vitro the cytotoxicity and the pathological effects of DON in short-term experiments on cells from non-tumour and tumour permanent cell lines and to compare their sensitivity. Cell cultivation of BALB/c 3T3, DEC 99, MDA-MB-231, MCF-7 and Hela cells was performed. Quantitative and qualitative methods evaluating cytotoxicity on the base of statistical and morphological analyses for determining the impact on the viability and proliferative activity were used: Neutral Red Uptake (NRU) cytotoxicity test, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test and fluorescence microscopy. The cytotoxic effect of DON was assessed after an exposure period of 24 h. DON treatment induced significant alterations in the growth and morphology of the cells, involving early and late apoptosis and necrosis signs. Statistically significant decrease of the viability of all cell lines was established at concentrations of DON starting from 1.9 µg/mL to 3.7 µg/mL, the mean IC50 concentrations were calculated. According to the IC50 values the hierarchical order of cell lines’ sensitivity was determined.

Urinary deoxynivalenol as a biomarker of exposure in different age, life stage and dietary practice population groups.

The Fusarium mycotoxin deoxynivalenol (DON) and its modified forms are present in most samples of grain and grain-based products. Due to the widespread presence of DON in these highly consumed food commodities, nearly all individuals are exposed to DON. Previous estimates of the dietary DON intake in Norway indicated that children's dietary intake is close to or exceed the TDI of 1µg/kg bw/day for the sum of DON and three modified forms. One aim of the current study was to determine whether the concentrations of DON in morning urine differ between population groups like men, women, children, vegetarians, and pregnant women. An additional aim was to compare a set of models for estimating the dietary intake of DON based on urinary DON concentrations and also compare these models with DON-intakes estimated using food consumption data. DON and metabolites were detected in the morning urine from 256 out of 257 individuals and with concentrations in similar range as reported from other countries. Children have higher urinary DON-concentration than adults and elderly. The urinary DON-concentration in pregnant women and vegetarians did not differ from other adults. The estimated intake of DON was higher for children than for other age groups on a body weight basis. The correlations between different models for estimating DON-intake based on urinary concentration as well as based on individual food consumption were good (0.79-0.99), but with some outliers. We conclude that Norwegians are exposed to DON in the same range as reported from other countries and that children have a higher exposure than adults. Furthermore, we conclude that intake estimates based on urinary DON concentration is a useful tool for evaluation of the exposure at population level, but due to outliers, the estimates for individuals are uncertain. There are also uncertainties in intake estimates both from food consumption and from urinary DON concentration, and we could not conclude on which approach provides the most accurate exposure estimate.

Development and Validation of an LC-MS/MS Based Method for the Determination of Deoxynivalenol and Its Modified Forms in Maize.

The Fusarium mycotoxin deoxynivalenol (DON) is a common contaminant of cereals and is often co-occurring with its modified forms DON-3-glucoside (D3G), 3-acetyl-DON (3ADON) or 15-acetyl-DON (15ADON). A stable-isotope dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS) based method for their determination in cereals was developed and validated for maize. Therefore, 13C-labelled D3G was enzymatically produced using 13C-DON and [13C6Glc]-sucrose and used as an internal standard (IS) for D3G, while uniformly 13C labelled IS was used for the other mycotoxins. Baseline separation was achieved for the critical peak pair DON/D3G, while 3ADON/15ADON could not be fully baseline separated after testing various reversed phase, fluorinated phase and chiral LC columns. After grinding, weighing and extracting the cereal samples, the raw extract was centrifuged and a mixture of the four 13C-labelled ISs was added directly in a microinsert vial. The subsequent analytical run took 7 min, followed by negative electrospray ionization and selected reaction monitoring on a triple quadrupole MS. Maize was used as a complex cereal model matrix for validation. The use of the IS corrected the occurring matrix effects efficiently from 76 to 98% for D3G, from 86 to 103% for DON, from 68 to 100% for 15ADON and from 63 to 96% for 3ADON.

The effect of Fusarium culmorum inoculation and deoxynivalenol application on proteome response in wheat cultivars Sumai 3 and SW Kadrilj

Fusarium head blight (FHB) represents a damaging disease of cereal spikes caused by mycotoxin-producing Fusarium fungi revealing adverse effects on grain quality and yield. Chinese spring wheat (Triticum aestivum L.) cv. Sumai 3 represents a major source of FHB resistance thanks to Fhb1 QTL on 3BS chromosome conferring resistance to FHB and encoding a lectin-like protein. The aim of our study lied in a comparison of proteome response to Fusarium culmorum inoculation and mycotoxin deoxynivalenol (DON) application at 10 d after inoculation (dai) in spikes of resistant wheat cultivar Sumai 3 and susceptible wheat cultivar SW Kadrilj. Proteome analysis revealed profound impact of Fusarium inoculation and mycotoxin application on plant energy metabolism. Fusarium inoculation decreased photosynthesis and ATP biosynthesis and increased the level of stress-protective proteins (chaperones such as Hsc70, lectins). Genotype related differences observed at 10 dai indicated an active acclimation in Sumai 3 as indicated by increased content of some enzymes involved in phenolics biosynthesis (phenylalanine ammonia lyase PAL, BAHD acyltransferase), jasmonate biosynthesis (lipoxygenase LOX), and oligosaccharide biosynthesis (sucrose synthase SuSy, UDP-glucose uridylyltransferase) which are an important part of glycoproteins such as lectins and other pathogen-responsive biomolecules. The study thus provides data on plant acclimation to Fusarium infection which may underlie superior resistance of Sumai 3 cultivar.

Agricultural mulching and fungicides\u2014impacts on fungal biomass, mycotoxin occurrence, and soil organic matter decomposition

Plastic and straw coverage (PC and SC) are often combined with fungicide application but their influence on fungicide entry into soil and the resulting consequences for soil quality are still unknown. The objective of this study was to investigate the impact of PC and SC, combined with fungicide application, on soil residual concentrations of fungicides (fenhexamid, cyprodinil, and fludioxonil), soil fungal biomass, mycotoxin occurrence, and soil organic matter (SOM) decomposition, depending on soil depth (0–10, 10–30, 30–60 cm) and time (1 month prior to fungicide application and respectively 1 week, 5 weeks, and 4 months afterwards). Soil analyses comprised fungicides, fusarium mycotoxins (deoxynivalenol, 15-acetyldeoxynivalenol, nivalenol, and zearalenone), ergosterol, soil microbial carbon and nitrogen, soil organic carbon, dissolved organic carbon, and pH. Fludioxonil and cyprodinil concentrations were higher under SC than under PC 1 week and 5 weeks after fungicide application (up to three times in the topsoil) but no differences were observed anymore after 4 months. Fenhexamid was not detected, presumably because of its fast dissipation in soil. The higher fludioxonil and cyprodinil concentrations under SC strongly reduced the fungal biomass and shifted microbial community towards larger bacterial fraction in the topsoil and enhanced the abundance and concentration of deoxynivalenol and 15-acetyldeoxynivalenol 5 weeks after fungicide application. Independent from the different fungicide concentrations, the decomposition of SOM was temporarily reduced after fungicide application under both coverage types. However, although PC and SC caused different concentrations of fungicide residues in soil, their impact on the investigated soil parameters was minor and transient (< 4 months) and hence not critical for soil quality.

Impact of milk thistle (Silybum marianum) on the mycotoxin caused redox-homeostasis imbalance of ducks liver

The Fusarium mycotoxins deoxynivalenol (DON) and zearalenone (ZEA) frequently contaminate grain crops, especially maize, the basis of poultry's feed. Mycotoxins enter the food chain and induce pathological changes in edible tissues. Milk thistle (Silybum marianum) has been used for the treatment of liver disease in humans because of its antioxidant and hepatoprotective effects, but its utility in veterinary use is poorly examined. To investigate possible protective properties against mycotoxin caused oxidative stress in poultry, pressed form of milk thistle seed (0.5%) was tested in white, female, Hungarian ducks over a feeding period of 47 days. Ducks were separated into 3 groups. The first group was fed with normal diet. The second group was fed with normal diet contaminated with DON (4.9 mg/kg) and ZEA (0.66 mg/kg). The third group received mycotoxin contaminated feed with milk thistle supplementation. Histological examination, markers of the redox status and metal element concentration measurements were carried out. The results showed alterations in the histological examination and in the redox homeostasis markers as a short-term effect by strengthening the antioxidant system. Acute exposure of mycotoxins caused an oxidative stress, which induced an effective antioxidant defensive response of the organism indicated by the free sulfhydryl group content (from 0.72 ± 0.06 to 0.77 ± 0.11) and the reducing power (0.49 ± 0.06 to 0.52 ± 0.08) elevation. The short-term free radical injury may be compensated by the liver resulting in decreased lipid peroxidation markers (malondialdehyde concentration: from 16.86 ± 0.49 to 0.94 ± 0.15, conjugated diene concentration: from 0.21 ± 0.07 to 0.17 ± 0.03). Silymarin further strengthtened the antioxidant defense by the elevation of sulfhydryl groups concentration and reducing power property resulted in decreased total scavenger capacity. However the concentration of lipid peroxidation markers were further elevated by the used antioxidant treatment (MDA: 5.2 ± 0.35, DC: 0.26 ± 0.08). In conclusion, the mycotoxin-contamination activated effectively the antioxidant system. The milk thistle supplementation has cytoprotective effects according to the histological findings, activated the antioxidant system, however the elevation of lipid peroxidation products need further explanation.

A quinone-dependent dehydrogenase and two NADPH-dependent aldo/keto reductases detoxify deoxynivalenol in wheat via epimerization in a Devosia strain

The Fusarium mycotoxin deoxynivalenol (DON) is typically controlled by fungicides. Here, we report DON detoxification using enzymes from the highly active Devosia strain D6-9 which degraded DON at 2.5 μg/min/108 cells. Strain D6-9 catabolized DON to 3-keto-DON and 3-epi-DON, completely removing DON in wheat. Genome analysis of three Devosia strains (D6-9, D17, and D13584), with strain D6-9 transcriptomes, identified three genes responsible for DON epimerization. One gene encodes a quinone-dependent DON dehydrogenase QDDH which oxidized DON into 3-keto-DON. Two genes encode the NADPH-dependent aldo/keto reductases AKR13B2 and AKR6D1 that convert 3-keto-DON into 3-epi-DON. Recombinant proteins expressed in Escherichia coli efficiently degraded DON in wheat grains. Molecular docking and site-directed mutagenesis revealed that residues S497, E499, and E535 function in QDDH's DON-oxidizing activity. These results advance potential microbial and enzymatic elimination of DON in agricultural samples and lend insight into the underlying mechanisms and molecular evolution of DON detoxification.

Regulation of the phytotoxic response of Arabidopsis thaliana to the Fusarium mycotoxin deoxynivalenol

Phytopathogenic fungi, such as Fusarium spp., synthesize trichothecene family phytotoxins. The type B trichothecene, namely deoxynivalenol (DON), is highly prevalent in small-grain cereals, such as wheat, corn and barley. DON is thought to be a virulence factor allowing plant infections and has an elicitor activity. We used the model plant Arabidopsis thaliana to evaluate the phytotoxic effects of DON in host plants. The growth of A. thaliana on media was significantly inhibited by DON. Moreover, DON induced cell death in detached leaves was observed by trypan blue staining. This is consistent with the phenomenon of organelle changes observed at the ultrastructural level. In our study, DON exposure stimulated oxidative bursts in the leaves, resulting in the concomitant down-regulation of antioxidant enzyme defense responses and up-regulation of lipid peroxidation. In addition, a real-time PCR analysis revealed that the DON treatment rapidly induced the transcription of defense genes, like AtrbohC and AtrbohD, and up-regulated the transcriptional level of the ascorbic acid peroxidase gene. These results suggested that DON phytotoxicity might result from reactive oxygen species pathways, and that DON production by the plant pathogen Fusarium graminearum can act as an elicitor influencing plant cell fate.

Deoxynivalenol Affects Proliferation and Expression of Activation-Related Molecules in Major Porcine T-Cell Subsets.

The Fusarium mycotoxin deoxynivalenol (DON) contaminates animal feed worldwide. In vivo, DON modifies the cellular protein synthesis, thereby also affecting the immune system. However, the functional consequences of this are still ill-defined. In this study, peripheral blood mononuclear cells from healthy pigs were incubated with different DON concentrations in the presence of Concanavalin A (ConA), a plant-derived polyclonal T-cell stimulant. T-cell subsets were investigated for proliferation and expression of CD8α, CD27, and CD28, which are involved in activation and costimulation of porcine T cells. A clear decrease in proliferation of all ConA-stimulated major T-cell subsets (CD4+, CD8+, and γδ T cells) was observed in DON concentrations higher than 0.4 µM. This applied in particular to naïve CD4+ and CD8+ T cells. From 0.8 μM onwards, DON induced a reduction of CD8α (CD4+) and CD27 expression (CD4+ and CD8+ T cells). CD28 expression was diminished in CD4+ and CD8+ T cells at a concentration of 1.6 µM DON. None of these effects were observed with the DON-derivative deepoxy-deoxynivalenol (DOM-1) at 16 µM. These results indicate that DON reduces T-cell proliferation and the expression of molecules involved in T-cell activation, providing a molecular basis for some of the described immunosuppressive effects of DON.

Stable Isotope-Assisted Plant Metabolomics: Investigation of Phenylalanine-Related Metabolic Response in Wheat Upon Treatment With the Fusarium Virulence Factor Deoxynivalenol.

The major Fusarium mycotoxin deoxynivalenol (DON) is a virulence factor in wheat and has also been shown to induce defense responses in host plant tissue. In this study, global and tracer labeling with 13C were combined to annotate the overall metabolome of wheat spikes and to evaluate the response of phenylalanine-related pathways upon treatment with DON. At anthesis, spikes of resistant and susceptible cultivars as well as two related near isogenic wheat lines (NILs) differing in the presence/absence of the major resistance QTL Fhb1 were treated with 1 mg DON or water (control), and samples were collected at 0, 12, 24, 48, and 96 h after treatment (hat). A total of 172 Phe-derived wheat constituents were detected with our untargeted approach employing 13C-labeled phenylalanine and subsequently annotated as flavonoids, lignans, coumarins, benzoic acid derivatives, hydroxycinnamic acid amides (HCAAs), as well as peptides. Ninety-six hours after the DON treatment, up to 30% of the metabolites biosynthesized from Phe showed significantly increased levels compared to the control samples. Major metabolic changes included the formation of precursors of compounds implicated in cell wall reinforcement and presumed antifungal compounds. In addition, also dipeptides, which presumably are products of proteolytic degradation of truncated proteins generated in the presence of the toxin, were significantly more abundant upon DON treatment. An in-depth comparison of the two NILs with correlation clustering of time course profiles revealed some 70 DON-responsive Phe derivatives. While several flavonoids had constitutively different abundance levels between the two NILs differing in resistance, other Phe-derived metabolites such as HCAAs and hydroxycinnamoyl quinates were affected differently in the two NILs after treatment with DON. Our results suggest a strong activation of the general phenylpropanoid pathway and that coumaroyl-CoA is mainly diverted towards HCAAs in the presence of Fhb1, whereas the metabolic route to monolignol(-conjugates), lignans, and lignin seems to be favored in the absence of the Fhb1 resistance quantitative trait loci.

The fate of Fusarium mycotoxins (deoxynivalenol and zearalenone) through wort fermenting by Saccharomyces yeasts (S. cerevisiae and S. pastorianus).

The aim of this study was to evaluate the effect of 15 commercial yeasts in the mitigation of the Fusarium mycotoxins deoxynivalenol (DON) and zearalenone (ZEN) during the brewing process. Saccharomyces strains (10 strains of S. cerevisiae and 5 of S. pastorianus) were used to ferment DON and ZEN contaminated wort. Wort samples were taken every 24 h during fermentation, while mycotoxin analysis in yeast was performed at the end of fermentation (96 h); additionally, pH and ethanol content were measured daily. For mycotoxin analysis, after immunoaffinity purification of sample extracts, analysis was performed using an Ultra-High-Pressure Liquid Chromatograph coupled with a diode array or fluorescence detector (UHPLC-DAD/FLD). Mycotoxin presence had no significant effect on the ethanol production during brewing. At the end of fermentation, 10-17% of DON and 30-70% of ZEN had been removed, 6% of the initial concentration of DON and 31% of the ZEN being adsorbed by the yeast. Beermakers must pay careful attention to the raw material since a high percentage of DON could be present at the end of the beer fermentation process. Future studies should focus on the quantification of "masked" mycotoxins that are relevant to food security.

The effect of thermal processing on the reduction of deoxynivalenol and zearalenone cereal content

Fusarium mycotoxins deoxynivalenol (DON) and zearalenone (ZEN) often contaminate cereals and cereal by-products. Certain thermal processing methods used in the food industry show promising results in terms of reduction of cereal contamination with mycotoxins. In order to establish the degree of DON and ZEN reduction in naturally contaminated cereals (maize, wheat and oat), this study investigated the effects of cooking, roasting and extrusion cooking, performed at different temperatures (100 – 220 °C) and for a different length of time (10 – 30 min) on these mycotoxins concentrations. Before and after the treatment, cereal samples were analysed for DON and ZEN concentrations using enzyme-linked immunosorbent assay (ELISA). In comparison to cooking, which achieved only a negligible mean mycotoxin reduction (of up to 8% for DON and 11% for ZEN), roasting and extrusion cooking resulted in a significantly more pronounced mycotoxin reduction (of up to 40% for DON &amp;amp; 46% for ZEN and of up to 75% for DON &amp;amp; 80% for ZEN, respectively) (p &amp;lt; 0.05). The results show similar effects of thermal processing on all of the studied cereals (p &amp;gt; 0.05), suggesting that extrusion cooking can be considered as an effective thermal method capable of reducing mycotoxin content in cereals.