Aflatoxin B1 and Epstein-Barr virus-induced CCL22 expression stimulates B cell infection.

Epstein-Barr Virus (EBV) infects more than 90% of the adult population worldwide. EBV infection is associated with Burkitt lymphoma (BL) though alone is not sufficient to induce carcinogenesis implying the involvement of co-factors. BL is endemic in African regions faced with mycotoxins exposure. Exposure to mycotoxins and oncogenic viruses has been shown to increase cancer risks partly through the deregulation of the immune response. A recent transcriptome profiling of B cells exposed to aflatoxin B1 (AFB1) revealed an upregulation of the Chemokine ligand 22 (CCL22) expression although the underlying mechanisms were not investigated. Here, we tested whether mycotoxins and EBV exposure may together contribute to endemic BL (eBL) carcinogenesis via immunomodulatory mechanisms involving CCL22. Our results revealed that B cells exposure to AFB1 and EBV synergistically stimulated CCL22 secretion via the activation of Nuclear Factor-kappa B pathway. By expressing EBV latent genes in B cells, we revealed that elevated levels of CCL22 result not only from the expression of the latent membrane protein LMP1 as previously reported but also from the expression of other viral latent genes. Importantly, CCL22 overexpression resulting from AFB1-exposure in vitro increased EBV infection through the activation of phosphoinositide-3-kinase pathway. Moreover, inhibiting CCL22 in vitro and in humanized mice in vivo limited EBV infection and decreased viral genes expression, supporting the notion that CCL22 overexpression plays an important role in B cell infection. These findings unravel new mechanisms that may underpin eBL development and identify novel pathways that can be targeted in drug development.

Population, Virulence, and Mycotoxin Profile of Fusarium spp. Associated With Basal Rot of Allium spp. in Vietnam.

Fusarium basal rot (FBR) is particularly problematic to Allium producers worldwide. In Vietnam, information on the profile of FBR is scarce, even though the presence of Fusarium spp. in Allium plants has long been recorded. In this study, a total of 180 isolates of Fusarium spp. were recovered from Allium bulbs/plants showing symptoms of FBR in 34 commercial Allium fields around Da Lat, Lam Dong, Vietnam. These isolates were identified to the species level by sequencing the internal transcribed spacer region and the translation elongation factor 1α gene. F. oxysporum was most prevalent (81%) in samples from all locations and Allium varieties, followed by F. solani (15%) and F. proliferatum (4%), which were only found in onion (Allium cepa L.). Pathogenicity tests on onion seedlings (56 isolates) and mini bulbs (10 isolates) indicated that onion can be infected by all of these species but virulence varied greatly between isolates. Moreover, isolates that were virulent on seedlings were sometimes not virulent on bulbs and vice versa, which points to a specialization of isolates for the host phenology. Mycotoxin analyses showed that the highest amounts of beauvericin were detected in seedlings and bulbs infected by F. oxysporum, whereas F. proliferatum was mainly responsible for the presence of fumonisin B1 in bulbs, suggesting a natural occurrence of beauvericin and fumonisin B1 in onions infected by these pathogens.

Mycotoxin management in a developing country context: A critical review of strategies aimed at decreasing dietary exposure to mycotoxins in Zimbabwe.

Mycotoxins are unavoidable environmental contaminants, which are found throughout the food chain, particularly in cereals. Mycotoxin management is not effective in developing countries, such as Zimbabwe, due to resource constraints, yet human health risk is evident. Various practical mitigation strategies that can be employed to decrease human dietary exposure to mycotoxins as a means of preliminary steps towards risk management are discussed. These strategies were stratified into two categories. First, crop/commodity-centred strategies, mainly the pre-harvest actions of cultivar selection, bio-control, as well as good agricultural practices (GAP), and the post-harvest actions including timeous harvesting, appropriate drying and storage technologies, are elaborated making use of hazard analysis critical control points (HACCP) principles. The role of legislation is also explored as a crop/commodity centred mitigation strategy. Second, human-centred strategies anchored on dietary diversity and the use of socio-cultural approaches as a direct means of reducing mycotoxin exposure are discussed. Finally, an integrated science-based mycotoxin management strategy, encompassing targeted legislation on mycotoxins, consumer education and information sharing, human and institutional capacity building, training and financing, is suggested in addition to GAP, as a means of reducing human health risk associated with mycotoxin exposure in Zimbabwe.HighlightsFarm-to-fork HACCP-based mycotoxin managementHuman-centred mycotoxin management approaches are keyAgronomy, technology and legislation critical in reducing mycotoxin exposure.

Dietary mycotoxins exposure and child growth, immune system, morbidity, and mortality: a systematic literature review.

The aim of this study was to systematically review associations between dietary mycotoxins exposure and child growth and morbidity of children aged 5 years or younger. Peer-reviewed literature was searched in MEDLINE, EMBASE, COCHRANE, CINAHL, Web of Science, and PsycINFO. Experimental and observational studies were considered. The exposures were dietary mycotoxins during pregnancy, lactation and childhood, and mycotoxins concentrations in the diet, breast milk, urine, and blood. From a total of 4869 references, 86 full-text papers were extracted of which 50 were included in this review. The methodological quality and risk of bias were evaluated and quality of the collective evidence was assessed using GRADE. Uncertainty remains whether mycotoxins exposure affects child growth, immunity and mortality and the overall quality of the evidence is very low. Overall however, we cannot rule out a possible association between dietary mycotoxins, in particular, AF and FUM and child malnutrition. Our analyses were limited by the reporting quality, difference in findings, heterogeneity of outcomes, mycotoxins detection methods, and the observational nature of most studies. Robust study designs with adequate sample size, use of validated biomarkers of exposure and assessment of co-occurrence of mycotoxins and their synergistic effects are required to provide the further evidence regarding a potential effect of dietary mycotoxins exposure on child growth and immunity.

Development of an automated flow-based spectrophotometric immunoassay for continuous detection of zearalenone.

Considering the widespread contaminations of food products with mycotoxins, it is important to develop, robust, time- and cost-effective detection methods. We developed and optimized an immunoassay using a continuous flow system for the detection of zearalenone (ZEN). The assay was performed in a flow mode using an automated sequential injection system. Time for an assay cycle was 18 Min. Under optimal conditions, the limit for quantification for ZEN was 0.40 µg L-1 with a linear dependency between concentration and signal amplitude between 0.10 and 10 µg L-1 . The assay proved to be robust and reliable with 13% relative standard deviation between measurements. By dissociating the antigen-antibody complex using a regeneration solution, we showed 50 times reusability of the immobilized antibodies without affecting the antigen-binding properties.

Investigation of age-related differences in toxicokinetic processes of deoxynivalenol and deoxynivalenol-3-glucoside in weaned piglets.

Age-related differences in toxicokinetic processes of deoxynivalenol (DON) and deoxynivalenol-3-glucoside (DON3G) were studied. DON3G [55.7 µg/kg bodyweight (BW)] and an equimolar dose of DON (36 µg/kg BW) were administered to weaned piglets (4 weeks old) by single intravenous and oral administration in a double two-way cross-over design. Systemic and portal blood was sampled at different time points pre- and post-administration and plasma concentrations of DON, DON3G and their metabolites were quantified using validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) and liquid chromatography-high-resolution mass spectrometry (LC-HRMS) methods. Data were processed using tailor-made compartmental toxicokinetic (TK) models to accurately estimate TK parameters. Results were statistically compared to data obtained in a previous study on 11-week-old pigs using identical experimental conditions. Significant age-related differences in intestinal and systemic exposure to both DON and DON3G were noted. Most remarkably, a significant difference was found for the absorbed fraction of DON3G, after presystemic hydrolysis to DON, in weaned piglets compared to 11-week-old piglets (83% vs 16%, respectively), assumed to be mainly attributed to the higher intestinal permeability of weaned piglets. Other differences in TK parameters could be assigned to a higher water/fat body ratio and longer gastrointestinal transit time of weaned piglets. Results may further refine current risk assessment concerning DON and DON3G in animals. Additionally, since piglets possibly serve as a human paediatric surrogate model, results may be extrapolated to human infants.

Immunochemical approaches for detection of aflatoxin B1 in herbal medicines.

INTRODUCTION: Aflatoxin B1 (AFB1) is a toxic low-molecular-weight secondary metabolite of Aspergillus flavus and A. parasiticus. AFB1 was classified as a Group I carcinogen by the World Health Organisation for Research on Cancer in 1993. AFB1 is an unavoidable natural contaminant of some herbal medicine, able to cause serious health issues for humans consuming the related medicine. OBJECTIVE: Therefore, this study aimed to develop an efficient fluorescence polarisation immunoassay (FPIA) and a rapid, low-cost, and easy-to-use membrane-based flow-through immunoassay (MBA) for determination of AFB1 in herbal medicine Origanum vulgare L., Rubus idaeus L., Urtica dioica L. and Sorbus aucuparia L. RESULTS: A cut-off level of the developed MBA was 0.8 ppb. Validation of the developed test was performed with blank and spiked samples. Using three naturally contaminated or three artificially spiked samples. The FPIA showed a linear working range of 8.6 to 64 ppb, and a half maximal inhibitory concentration (IC50 ) of 24 ppb. CONCLUSION: The results were in good correlation with the enzymelinked immunosorbent assay (ELISA) results (the IC50 0.1 ppb). Both the sample preparation and analysis are simple, cost-effective and easy to perform on-site in non-laboratory environments. Liquid chromatography with tandem mass spectrometry (LC-MS/MS) was used as a confirmatory technique.

Chemical repertoire and biosynthetic machinery of the Aspergillus flavus secondary metabolome: A review.

Filamentous fungi represent a rich source of extrolites, including secondary metabolites (SMs) comprising a great variety of astonishing structures and interesting bioactivities. State-of-the-art techniques in genome mining, genetic manipulation, and secondary metabolomics have enabled the scientific community to better elucidate and more deeply appreciate the genetic and biosynthetic chemical arsenal of these microorganisms. Aspergillus flavus is best known as a contaminant of food and feed commodities and a producer of the carcinogenic family of SMs, aflatoxins. This fungus produces many SMs including polyketides, ribosomal and nonribosomal peptides, terpenoids, and other hybrid molecules. This review will discuss the chemical diversity, biosynthetic pathways, and biological/ecological role of A. flavus SMs, as well as their significance concerning food safety and security.

Mycotoxin exposure and human cancer risk: A systematic review of epidemiological studies.

In recent years, there has been an increasing interest in investigating the carcinogenicity of mycotoxins in humans. This systematic review aims to provide an overview of data linking exposure to different mycotoxins with human cancer risk. Publications (2019 and earlier) of case-control or longitudinal cohort studies were identified in PubMed and EMBASE. These articles were then screened by independent reviewers and their quality was assessed according to the Newcastle-Ottawa scale. Animal, cross-sectional, and molecular studies satisfied criteria for exclusion. In total, 14 articles were included: 13 case-control studies and 1 longitudinal cohort study. Included articles focused on associations of mycotoxin exposure with primary liver, breast, and cervical cancer. Overall, a positive association between the consumption of aflatoxin-contaminated foods and primary liver cancer risk was verified. Two case-control studies in Africa investigated the relationship between zearalenone and its metabolites and breast cancer risk, though conflicting results were reported. Two case-control studies investigated the association between hepatocellular carcinoma and fumonisin B1 exposure, but no significant associations were observed. This systematic review incorporates several clear observations of dose-dependent associations between aflatoxins and liver cancer risk, in keeping with IARC Monograph conclusions. Only few human epidemiological studies investigated the associations between mycotoxin exposures and cancer risk. To close this gap, more in-depth research is needed to unravel evidence for other common mycotoxins, such as deoxynivalenol and ochratoxin A. The link between mycotoxin exposures and cancer risk has mainly been established in experimental studies, and needs to be confirmed in human epidemiological studies to support the evidence-based public health strategies.

Detection of toxins involved in foodborne diseases caused by Gram-positive bacteria.

Bacterial toxins are food safety hazards causing about 10% of all reported foodborne outbreaks in Europe. Pertinent to Gram-positive pathogens, the most relevant toxins are emetic toxin and diarrheal enterotoxins of Bacillus cereus, neurotoxins of Clostridium botulinum, enterotoxin of Clostridium perfringens, and a family of enterotoxins produced by Staphylococcus aureus and some other staphylococci. These toxins are the most important virulence factors of respective foodborne pathogens and a primary cause of the related foodborne diseases. They are proteins or peptides that differ from each other in their size, structure, toxicity, toxicological end points, solubility, and stability, types of food matrix to which they are mostly related to. These differences influence the characteristics of required detection methods. Therefore, detection of these toxins in food samples, or detection of toxin production capacity in the bacterial isolate, remains one of the cornerstones of microbial food analysis and an essential tool in understanding the relevant properties of these toxins. Advanced research has led into new insights of the incidence of toxins, mechanisms of their production, their physicochemical properties, and their toxicological mode of action and dose-response profile. This review focuses on biological, immunological, mass spectrometry, and molecular assays as the most commonly used detection and quantification methods for toxins of B. cereus, C. botulinum, C. perfringens, and S. aureus. Gathered and analyzed information provides a comprehensive blueprint of the existing knowledge on the principles of these assays, their application in food safety, limits of detection and quantification, matrices in which they are applicable, and type of information they provide to the user.

Counteracting in Vitro Toxicity of the Ionophoric Mycotoxin Beauvericin-Synthetic Receptors to the Rescue.

Beauvericin (BEA) and enniatins are toxic ionophoric cyclodepsipeptides that mainly occur in grains. As such, their presence in food commodities poses a concern for public health. To date, despite recent European Food Safety Authority emphasis on the need for more data to evaluate long-term toxicity effects, no suitable affinity reagents are available to detect the presence of BEA and derivatives in food samples. We here report on the synthesis of a small library of artificial receptors with varying cavity sizes and different hydrophobic building blocks. Immobilization of one of the receptors on solid support resulted in a strong retention of beauvericin, thus revealing promising properties as solid-phase extraction material for sample pretreatment. Furthermore, treatment of HepG2 cells with the most promising receptor markedly reduced beauvericin-induced cytotoxicity, hinting toward the possibility of using synthetic receptors as antidotes against ionophoric toxins.

The role of roughage provision on the absorption and disposition of the mycotoxin deoxynivalenol and its acetylated derivatives in calves: from field observations to toxicokinetics.

A clinical case in Belgium demonstrated that feeding a feed concentrate containing considerable levels of deoxynivalenol (DON, 1.13 mg/kg feed) induced severe liver failure in 2- to 3-month-old beef calves. Symptoms disappeared by replacing the highly contaminated corn and by stimulating ruminal development via roughage administration. A multi-mycotoxin contamination was demonstrated in feed samples collected at 15 different veal farms in Belgium. DON was most prevalent, contaminating 80% of the roughage samples (mixed straw and maize silage; average concentration in positives: 637 ± 621 µg/kg, max. 1818 µg/kg), and all feed concentrate samples (411 ± 156 µg/kg, max. 693 µg/kg). In order to evaluate the impact of roughage provision and its associated ruminal development on the gastro-intestinal absorption and biodegradation of DON and its acetylated derivatives (3- and 15-ADON) in calves, a toxicokinetic study was performed with two ruminating and two non-ruminating male calves. Animals received in succession a bolus of DON (120 µg/kg bodyweight (BW)), 15-ADON (50 µg/kg BW), and 3-ADON (25 µg/kg) by intravenous (IV) injection or per os (PO) in a cross-over design. The absolute oral bioavailability of DON was much higher in non-ruminating calves (50.7 ± 33.0%) compared to ruminating calves (4.1 ± 4.5%). Immediately following exposure, 3- and 15-ADON were hydrolysed to DON in ruminating calves. DON and its acetylated metabolites were mainly metabolized to DON-3-glucuronide, however, also small amounts of DON-15-glucuronide were detected in urine. DON degradation to deepoxy-DON (DOM-1) was only observed to a relevant extent in ruminating calves. Consequently, toxicity of DON in calves is closely related to roughage provision and the associated stage of ruminal development.

Metabolic Profile, Bioavailability and Toxicokinetics of Zearalenone-14-Glucoside in Rats after Oral and Intravenous Administration by Liquid Chromatography High-Resolution Mass Spectrometry and Tandem Mass Spectrometry.

Zearalenone-14-glucoside (ZEN-14G), a key modified mycotoxin, has attracted a great deal of attention due to the possible conversion to its free form of zearalenone (ZEN) exerting toxicity. In this study, the toxicokinetics of ZEN-14G were investigated in rats after oral and intravenous administration. The plasma concentrations of ZEN-14G and its major five metabolites were quantified using a validated liquid chromatography tandem mass spectrometry (LC-MS/MS) method. The data were analyzed via non-compartmental analysis using software WinNonlin 6.3. The results indicated that ZEN-14G was rapidly hydrolyzed into ZEN in vivo. In addition, the major parameters of ZEN-14G following intravenous administration were: area under the plasma concentration-time curve (AUC), 1.80 h·ng/mL; the apparent volume of distribution (VZ), 7.25 L/kg; and total body clearance (CL), 5.02 mL/h/kg, respectively. After oral administration, the typical parameters were: AUC, 0.16 h·ng/mL; VZ, 6.24 mL/kg; and CL, 4.50 mL/h/kg, respectively. The absolute oral bioavailability of ZEN-14G in rats was about 9%, since low levels of ZEN-14G were detected in plasma, which might be attributed to its extensive metabolism. Therefore, liquid chromatography high-resolution mass spectrometry (LC-HRMS) was adopted to clarify the metabolic profile of ZEN-14G in rats' plasma. As a result, eight metabolites were identified in which ZEN-14-glucuronic acid (ZEN-14GlcA) had a large yield from the first time-point and continued accumulating after oral administration, indicating that ZEN-14-glucuronic acid could serve a potential biomarker of ZEN-14G. The obtained outcomes would prompt the accurate safety evaluation of ZEN-14G.

Optimizing the Use of Zebrafish Feeding Trials for the Safety Evaluation of Genetically Modified Crops.

In Europe, the toxicological safety of genetically modified (GM) crops is routinely evaluated using rodent feeding trials, originally designed for testing oral toxicity of chemical compounds. We aimed to develop and optimize methods for advancing the use of zebrafish feeding trials for the safety evaluation of GM crops, using maize as a case study. In a first step, we evaluated the effect of different maize substitution levels. Our results demonstrate the need for preliminary testing to assess potential feed component-related effects on the overall nutritional balance. Next, since a potential effect of a GM crop should ideally be interpreted relative to the natural response variation (i.e., the range of biological values that is considered normal for a particular endpoint) in order to assess the toxicological relevance, we established natural response variation datasets for various zebrafish endpoints. We applied equivalence testing to calculate threshold equivalence limits (ELs) based on the natural response variation as a method for quantifying the range within which a GM crop and its control are considered equivalent. Finally, our results illustrate that the use of commercial control diets (CCDs) and null segregant (NS) controls (helpful for assessing potential effects of the transformation process) would be valuable additions to GM safety assessment strategies.

Impact of fungicides and weather on cyclodepsipeptide-producing Fusarium spp. and beauvericin and enniatin levels in wheat grains.

BACKGROUND: Fusarium head blight (FHB) is a well-known disease of wheat caused by a complex of Fusarium species. In this research, an extensive study on the occurrence of the emerging Fusarium cyclodepsipeptide mycotoxins beauvericin and enniatins was conducted in Belgian wheat grains harvested in 2015 and 2016. To assess the link between Fusarium species and their mycotoxin production, ultra-performance liquid chromatography-tandem mass spectrometry was used to quantify the cyclodepsipeptide mycotoxins, while quantitative polymerase chain reaction was applied to quantify the presence of Fusarium species. RESULTS: It was shown that enniatins were mainly associated with the presence of F. avenaceum, while beauvericin, despite its low incidence, correlated significantly with F. poae. The application of fungicides resulted in a species shift and in the occurring mycotoxins. Concerning the effect of weather conditions, it was seen that levels of enniatins were positively correlated with the rainfall in May and June, while a negative correlation was observed with rainfall in the first half of July. CONCLUSION: Our study provides new insights into the occurrence of the emerging cyclodepsipeptide mycotoxins in an agro-ecosystem in which fungicides are the main control measure against FHB. It seems that beauvericin and enniatin levels are affected by different parameters and behave differently upon application of fungicides. © 2018 Society of Chemical Industry.

Identification and functional analysis of the aspergillic acid gene cluster in Aspergillus flavus.

Aspergillus flavus can colonize important food staples and produce aflatoxins, a group of toxic and carcinogenic secondary metabolites. Previous in silico analysis of the A. flavus genome revealed 56 gene clusters predicted to be involved in the biosynthesis of secondary metabolites. A. flavus secondary metabolites produced during infection of maize seed are of particular interest, especially with respect to their roles in the biology of the fungus. A predicted nonribosomal peptide synthetase-like (NRPS-like) gene, designated asaC (AFLA_023020), present in the uncharacterized A. flavus secondary metabolite gene cluster 11 was previously shown to be expressed during the earliest stages of maize kernel infection. Cluster 11 is composed of six additional genes encoding a number of putative decorating enzymes as well as a transporter and transcription factor. We generated knock-out mutants of the seven predicted cluster 11 genes. LC-MS analysis of extracts from knockout mutants of these genes showed that they were responsible for the synthesis of the previously characterized antimicrobial mycotoxin aspergillic acid. Extracts of the asaC mutant showed no production of aspergillic acid or its precursors. Knockout of the cluster 11 P450 oxidoreductase afforded a pyrazinone metabolite, the aspergillic acid precursor deoxyaspergillic acid. The formation of hydroxyaspergillic acid was abolished in a desaturase/hydroxylase mutant. The hydroxamic acid functional group in aspergillic acid allows the molecule to bind to iron resulting in the production of a red pigment in A. flavus identified previously as ferriaspergillin. A reduction of aflatoxin B1 and cyclopiazonic acid that correlated with reduced fungal growth was observed in maize kernel infection assays when aspergillic acid biosynthesis in A. flavus is halted.

Fluorescently labelled multiplex lateral flow immunoassay based on cadmium-free quantum dots.

A sensitive tool for simultaneous qualitative detection of two mycotoxins based on use of non-cadmium quantum dots (QDs) is presented for the first time. QDs have proven themselves as promising fluorescent labels for biolabeling and chemical analysis. With an increasing global tendency to regulate and limit the use of hazardous elements, indium phosphide (InP) QDs are highlighted as environmentally-friendly alternatives to the highly efficient and well-studied, but potentially toxic Cd- and Pb-based QDs. Here, we developed water-soluble InP QDs-based fluorescent nanostructures. They consisted of core/shell InP/ZnS QDs enrobed in a silica shell that allowed the water solubility (QD@SiO2). Then we applied the QD@SiO2 as novel, silica shell-encapsulated fluorescent labels in immunoassays for rapid multiplexed screening. Two mycotoxins, zearalenone and deoxynivalenol, were simultaneously detected in maize and wheat, since the two QD@SiO2 labelled conjugates emit at two different, individually detectable wavelengths. The cutoff values for the simultaneous determination were 50 and 500µgkg-1 for zearalenone and deoxynivalenol, respectively, in both maize and wheat. Liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) was used to confirm the result.

In-house validation of a rapid and efficient procedure for simultaneous determination of ergot alkaloids and other mycotoxins in wheat and maize.

A fundamental step in addressing the global problem of mycotoxins is the development of highly sensitive, multi-class extraction and detection methods. This constitutes a field of research that has in recent years enjoyed a steady advance. Such methods, generally based on liquid chromatography coupled to mass spectrometry, are widely reported successfully detecting various mycotoxins in different food and feed samples. In this work, an innovative approach to multi-class mycotoxin control is proposed, offering specific advantages: a broader inclusion of more mycotoxin classes, robust and thorough extraction for all target compounds despite their varied chemical properties, and determination of all analytes from a single injection. The method involved the extraction and quantification of the main mycotoxins produced by Aspergillus, Fusarium, and Penicillium fungi, as well as their reported derivatives, together with 12 other compounds most commonly produced by Claviceps purpurea. The popularly reported QuEChERS technique has been reduced to a simple "salting-out liquid-liquid extraction" (SO-LLE) to obtain the most efficient extraction of the aforementioned mycotoxin classes in a very short time. This is in particular extremely important in ensuring correct determination of individual ergot alkaloids, for which short and robust sample preparation as well as short analytical sequences were key for minimizing the epimerization during analysis. The analyses of wheat and maize samples were performed using ultra-high performance liquid chromatography coupled with tandem mass spectrometry. Matrix-matched calibration curves were established and limits of quantification were below the maximum levels established by the EU regulation. The precision (repeatability and intermediate precision) was lower than 13% in all cases and recoveries ranged between 60 and 98% in maize and between 62 and 103% in wheat, fulfilling the current legislation. The method was applied to study the co-occurrence of these mycotoxins in wheat (n = 13) and maize (n = 15) samples from six European countries. A successful quantification of 23 different mycotoxins, from all major classes, in 85% of wheat and 93% of maize samples was achieved.

Deglucosylation of zearalenone-14-glucoside in animals and human liver leads to underestimation of exposure to zearalenone in humans.

Zearalenone-14-glucoside (ZEN-14G), the modified mycotoxin of zearalenone (ZEN), has attracted considerable attention due to its high potential to be hydrolyzed into ZEN, which would exert toxicity. It has been confirmed that the microflora could metabolize ZEN-14G to ZEN. However, the metabolic profile of ZEN-14G and whether it could be deglucosidated in the liver are unknown. To thoroughly investigate the metabolism of ZEN-14G, in vitro metabolism including phase I and phase II metabolism was studied using liquid chromatography coupled to high-resolution mass spectrometry. Additionally, in vivo metabolism of ZEN-14G was conducted in model animals, rats, by oral administration. As a result, 29 phase I metabolites and 6 phase II metabolites were identified and significant inter-species metabolic differences were observed as well. What is more, ZEN-14G could be considerably deglucosidated into its free form of ZEN after the incubation with animals and human liver microsomes in the absence of NADPH, which was mainly metabolized by human carboxylesterase CES-I and II. Furthermore, results showed that the major metabolic pathways of ZEN-14G were deglucosylation, hydroxylation, hydrogenation and glucuronidation. Although interspecies differences in the biotransformation of ZEN-14G were observed, ZEN, α-ZEL-14G, ß-ZEL-14G, α-ZEL, ZEN-14G-16GlcA and ZEN-14GlcA were the major metabolites of ZEN-14G. Additionally, a larger yield of 6-OH-ZEN-14G and 8-OH-ZEN-14G was also observed in human liver microsomes. The obtained data would be of great importance for the safety assessment of modified mycotoxin, ZEN-14G, and provide another perspective for risk assessment of mycotoxin.

Mycotoxin Biomarkers of Exposure: A Comprehensive Review.

To date, the use of biomarkers has become generally accepted. Biomarker-driven research has been proposed as a successful method to assess the exposure to xenobiotics by using concentrations of the parent compounds and/or metabolites in biological matrices such as urine or blood. However, the identification and validation of biomarkers of exposure remain a challenge. Recent advances in high-resolution mass spectrometry along with new analytical (post-acquisition data-mining) techniques will improve the quality and output of the biomarker identification process. Chronic or even acute exposure to mycotoxins remains a daily fact, and therefore it is crucial that the mycotoxins' metabolism is unravelled so more knowledge on biomarkers in humans and animals is acquired. This review aims to provide the scientific community with a comprehensive overview of reported in vitro and in vivo mycotoxin metabolism studies in relation to biomarkers of exposure for deoxynivalenol, nivalenol, fusarenon-X, T-2 toxin, diacetoxyscirpenol, ochratoxin A, citrinin, fumonisins, zearalenone, aflatoxins, and sterigmatocystin.