Emesis to trichothecene deoxynivalenol and its congeners correspond to secretion of peptide YY and 5-HT.

The type B trichothecenes pollute food crops and have been associated to alimentary toxicosis resulted in emetic reaction in human and animal. This group of mycotoxins consists deoxynivalenol (DON) and four structurally related congeners: 3-acetyl-deoxynivalenol (3-ADON), 15-acetyl deoxynivalenol (15-ADON), nivalenol (NIV) and 4-acetyl-nivalenol (fusarenon X, FX). While emesis induced by intraperitoneally dosed to DON in the mink has been related to plasma up-grading of 5-hydroxytryptamine (5-HT) and neurotransmitters peptide YY (PYY), the impact of oral dosing with DON or its four congeners on secretion of these chemical substances have not been established. The aim of this work was to contraste emetic influence to type B trichothecene mycotoxins by orally dosing and involve these influence to PYY and 5-HT. All five toxins attracted marked emetic reaction that are relevant to elevated PYY and 5-HT. The reduction in vomiting induced by the five toxins and PYY was due to blocking of the neuropeptide Y2 receptor. The inhibition of the induced vomiting response by 5-HT and all five toxins is regulated by the 5-HT3 receptor inhibitor granisetron. In a word, our results indicate that PYY and 5-HT take a key role in the emetic reaction evoked by type B trichothecenes.

Pasta cooking influence on in vitro bioaccessibility of type B trichothecenes, acrylamide and hydroxymethylfurfural.

The study evaluated the effect of cooking time on the levels of type B trichothecenes (TCTB), acrylamide (AA) and hydroxymethylfurfural (HMF) in semolina pasta and their bioaccessibilities in order to propose strategies to reduce the daily exposure of these natural and processing contaminants. Three brands of commercial pasta were submitted to different cooking times (7, 10 and 13 min). Subsequently, the in vitro bioaccessibility trials, permeation across the intestinal membrane and estimation of daily exposure were carried out. The lowest cooking time (7 min) resulted in high reductions of TCTB (88%) and AA + HMF (76.7%) contents found on the raw pasta. The concentrations of deoxynivalenol (DON) and AA were higher after the digestion (bioaccessibilities >100%) than after the pasta cooking. About 25.6% of DON and 100% of AA found in the small intestine digestible fraction were able to permeate the intestinal membrane. The risk of exposure was below the recommended safe limits since the estimated daily exposure values were 0.22 µg/kg per body weight/day for DON and 0.26 µg/kg per body weight/day for AA. Therefore, cooking pasta for 7 min at a pasta:water ratio of 1:10 (w/v) mitigates the contaminants and promotes the greater formation of resistant starch.

Free and Modified Mycotoxins in Organic and Conventional Oats (Avena sativa L.) Grown in Scotland.

Small grain cereals are frequently infected with mycotoxigenic Fusarium fungi. Oats have a particularly high risk of contamination with type A trichothecene mycotoxins; their glucoside conjugates have also been reported. Agronomy practices, cereal variety and weather conditions have been suggested to play a role in Fusarium infection in oats. The current study investigates concentrations of free and conjugated Fusarium mycotoxins in organic and conventional oats grown in Scotland. In 2019, 33 milling oat samples (12 organic, 21 conventional) were collected from farmers across Scotland, together with sample questionnaires. Samples were analysed for 12 mycotoxins (type A trichothecenes T-2-toxin, HT-2-toxin, diacetoxyscirpenol; type B trichothecenes deoxynivalenol, nivalenol; zearalenone and their respective glucosides) using LC-MS/MS. The prevalence of type A trichothecenes T-2/HT-2 was very high (100% of conventional oats, 83% of organic oats), whereas type B trichothecenes were less prevalent, and zearalenone was rarely found. T-2-glucoside and deoxynivalenol-glucoside were the most prevalent conjugated mycotoxins (36 and 33%), and co-occurrence between type A and B trichothecenes were frequently observed (66% of samples). Organic oats were contaminated at significantly lower average concentrations than conventional oats, whereas the effect of weather parameters were not statistically significant. Our results clearly indicate that free and conjugated T-2- and HT-2-toxins pose a major risk to Scottish oat production and that organic production and crop rotation offer potential mitigation strategies.

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.

Development of a certified reference material for the accurate determination of type B trichothecenes in corn.

A corn flour certified reference material (KRISS CRM 108-01-011) was developed to ensure accurate and reliable measurements of type B trichothecenes (deoxynivalenol, nivalenol, 3-acetyldeoxynivalenol, 15-acetyldeoxynivalenol), and deoxynivalenol-3-glucoside. The material was freeze-dried, ground, sieved, and well-mixed. The final produced CRM was packaged at 14 g per unit and stored at -70 °C. The certification was performed using isotope dilution-liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS). For simultaneous characterization and homogeneity assessments, ten units were randomly selected and analyzed. The among-unit relative standard deviations were below 1 % for all mycotoxins, indicating excellent homogeneity of the CRM. The stability of the CRM was also assessed at various designated temperatures and test periods. The uncertainties of the certified values varied between 2.4 % and 6.2 %, thereby confirming their higher-order metrological quality to provide references for testing laboratories. In case of deoxynivalenol-3-glucoside, an information value was assigned due to the lack of its traceability to the SI units.

Substance P and Glucagon-like Peptide-17-36 Amide Mediate Anorexic Responses to Trichothecene Deoxynivalenol and Its Congeners.

Type B trichothecenes commonly contaminate cereal grains and include five structurally related congeners: deoxynivalenol (DON), 3-acetyldeoxynivalenol (3-ADON), 15-acetyldeoxynivalenol (15-ADON), fusarenon X (FX), and nivalenol (NIV). These toxins are known to have negative effects on human and animal health, particularly affecting food intake. However, the pathophysiological basis for anorexic effect is not fully clarified. The purpose of this study is to explore the potential roles of the brain-gut peptides substance P (SP) and glucagon-like peptide-17-36 amide (GLP-1) in anorexic responses induced by type B trichothecenes following both intraperitoneal (IP) and oral administration. SP and GLP-1 were elevated at 1 or 2 h and returned to basal levels at 6 h following exposure to DON and both ADONs. FX induced the production of both brain gut peptides with initial time at 1 or 2 h and duration > 6 h. Similar to FX, exposing IP to NIV caused elevations of SP and GLP-1 at 1 h and lasted more than 6 h, whereas oral exposure to NIV only increased both brain gut peptides at 2 h. The neurokinin-1 receptor (NK-1R) antagonist Emend® dose-dependently attenuated both SP- and DON-induced anorexic responses. Pretreatment with the GLP-1 receptor (GLP-1R) antagonist Exending9-39 induced a dose-dependent attenuation of both GLP-1- and DON-induced anorexic responses. To summarize, the results suggest that both SP and GLP-1 play important roles in anorexia induction by type B trichothecenes.

Searching for the Fusarium spp. Which Are Responsible for Trichothecene Contamination in Oats Using Metataxonomy to Compare the Distribution of Toxigenic Species in Fields from Spain and the UK.

The contamination of oats with Fusarium toxins poses a high risk for food safety. Among them, trichothecenes are the most frequently reported in European oats, especially in northern countries. The environmental conditions related to the climate change scenario might favour a distribution shift in Fusarium species and the presence of these toxins in Southern European countries. In this paper, we present an ambitious work to determine the species responsible for trichothecene contamination in Spanish oats and to compare the results in the United Kingdom (UK) using a metataxonomic approach applied to both oat grains and soil samples collected from both countries. Regarding T-2 and HT-2 toxin producers, F. langsethiae was detected in 38% and 25% of the oat samples from the UK and Spain, respectively, and to the best of our knowledge, this is the first report of the detection of this fungus in oats from Spain. The relevant type B trichothecene producer, F. poae, was the most frequently detected Fusarium species in oats from both origins. Other important trichothecene producers, such as the Fusarium tricinctum species complex or Fusarium cerealis, were also frequently detected in oat fields. Many Fusarium toxins, including T-2 and HT-2 toxins, deoxynivalenol, or nivalenol, were detected in oat samples. The results obtained in this work revealed a clear change in the distribution of trichothecene producers and the necessity to establish the potential of these species to colonize oats and their ability to produce mycotoxins.

The distribution and type B trichothecene chemotype of Fusarium species associated with head blight of wheat in South Africa during 2008 and 2009.

Fusarium head blight (FHB) of wheat occurs commonly in irrigation regions of South Africa and less frequently in dryland regions. Previous surveys of Fusarium species causing FHB identified isolates using morphological characters only. This study reports on a comprehensive characterisation of FHB pathogens conducted in 2008 and 2009. Symptomatic wheat heads were collected from the Northern Cape, KwaZulu-Natal (KZN), Bushveld and eastern Free State (irrigation regions), and from one field in the Western Cape (dryland region). Fusarium isolates were identified with species-specific primers or analysis of partial EF-1α sequences. A representative subset of isolates was characterized morphologically. In total, 1047 Fusarium isolates were collected, comprising 24 species from seven broad species complexes. The F. sambucinum (FSAMSC) and F. incarnatum-equiseti species complexes (FIESC) were most common (83.5% and 13.3% of isolates, respectively). The F. chlamydosporum (FCSC), F. fujikuroi (FFSC), F. oxysporum (FOSC), F. solani (FSSC), and F. tricinctum species complexes (FTSC) were also observed. Within the FSAMSC, 90.7% of isolates belonged to the F. graminearum species complex (FGSC), accounting for 75.7% of isolates. The FGSC was the dominant Fusaria in all four irrigation regions. F. pseudograminearum dominated at the dryland field in the Western Cape. The Northern Cape had the highest species diversity (16 Fusarium species from all seven species complexes). The type B trichothecene chemotype of FGSC and related species was inferred with PCR. Chemotype diversity was limited (15-ADON = 90.1%) and highly structured in relation to species differences. These results expand the known species diversity associated with FHB in South Africa and include first reports of F. acuminatum, F. armeniacum, F. avenaceum, F. temperatum, and F. pseudograminearum from wheat heads in South Africa, and of F. brachygibbosum, F. lunulosporum and F. transvaalense from wheat globally. Potentially novel species were identified within the FCSC, FFSC, FOSC, FSAMSC, FIESC and FTSC.

Production of type-B trichothecenes by Fusarium meridionale, F. graminearum, and F. austroamericanum in wheat plants and rice medium.

Food security goes beyond food being available; the food needs to be free of contaminants. Trichothecenes mycotoxins, produced by Fusarium fungus, are. among the most frequently found contaminants of wheat. In this study, we evaluated the production of trichothecenes Deoxynivalenol (DON), 3-acetyldeoxynivalenol (3-AcDON), 15-acetyldeoxynivalenol (15-AcDON), and nivalenol (NIV) by Fusarium meridionale, F. austroamericanum, and F. graminearum grown in wheat plants and rice medium. Fusarim meridionale was efficient only in the production of NIV (production range (pr) from 1340 to 2864 µg kg-1 in wheat plant), and F. austroamericanum in the production of 3-AcDON (pr from 50 to 192 µg kg-1 in wheat plant, and from 986 to 7045 µg kg-1 in rice medium) and DON (pr from 4076 to 13,701 µg kg-1 in wheat plant, and from 184 to 43,395 µg kg-1 in rice medium). Already, F. graminearum was efficient in the production of 3-AcDON only in rice medium (pr from 81 to 2342 µg kg-1), 15-AcDON in wheat plant (pr from 80 to 295 µg kg-1) and in rice medium (pr from 436 to 8597 µg kg-1), and DON also in wheat plant (pr from 7746 to 12,046 µg kg-1) and in rice medium (pr from 695 to 49,624 µg kg-1). The specificity of F. meridionale in the production of NIV but not the production of DON could generate a food security problem in regions where this species occurs and the amounts of NIV in grains and derivatives are not regulated in the food chain, as in Brazil.

Survey of Freshly Harvested Oat Grains from Southern Brazil Reveals High Incidence of Type B Trichothecenes and Associated Fusarium Species.

The current study investigated the fungal diversity in freshly harvested oat samples from the two largest production regions in Brazil, Paraná (PR) and Rio Grande do Sul (RS), focusing primarily on the Fusarium genus and the presence of type B trichothecenes. The majority of the isolates belonged to the Fusarium sambucinum species complex, and were identified as F. graminearum sensu stricto (s.s.), F. meridionale, and F. poae. In the RS region, F. poae was the most frequent fungus, while F. graminearum s.s. was the most frequent in the PR region. The F. graminearum s.s. isolates were 15-ADON genotype, while F. meridionale and F. poae were NIV genotype. Mycotoxin analysis revealed that 92% and 100% of the samples from PR and RS were contaminated with type B trichothecenes, respectively. Oat grains from PR were predominantly contaminated with DON, whereas NIV was predominant in oats from RS. Twenty-four percent of the samples were contaminated with DON at levels higher than Brazilian regulations. Co-contamination of DON, its derivatives, and NIV was observed in 84% and 57.7% of the samples from PR and RS, respectively. The results provide new information on Fusarium contamination in Brazilian oats, highlighting the importance of further studies on mycotoxins.

Identification of type B trichothecenes and zearalenone in Chilean cereals by planar chromatography coupled to mass spectroscopy.

High-performance thin-layer chromatography (HPTLC) and HPTLC coupled with mass spectrometry (MS) methods were described for the simultaneous determination of zearalenone (ZEA); type B trichothecenes (TCT-B); nivalenol (NIV) and deoxynivalenol (DON) along with its acetylated derivatives: 3-acetyldeoxynivalenol (3-ADON) and 15-acetyldeoxynivalenol (15-ADON). The extract samples were cleaned-up with Bond Elut Mycotoxin® solid-phase extraction cartridges. Then, separation was performed on HPTLC silica gel 60 F254 plates using toluene, ethyl acetate and formic acid (1:8:1 v/v/v) as mobile phase. Derivatisation was then performed with 10% aluminium trichloride in 50% methanol. Mycotoxin standards and spiked cereals grains were identified by UV spots at 366 nm, with retention factors (RF) of 0.20 (NIV), 0.39 (DON), 0.45 (15-ADON), 0.50 (3-ADON) and 0.60 (ZEA). Some parameters of validation were determined. Calibration data (n = 5) fitted a linear regression model with determination coefficients, R2 > 0.99. The recovery was determined in triplicate at two levels, ranging from 84.3 ± 2.2% to 114.2 ± 11.7%. Detection limits ranged from 80 to 120 µg kg-1 and quantification limits ranged from 120.0 to 200 µg kg-1. The analysis by HPTLC/electrospray (ESI)-MS in negative mode confirmed the presence of TCT-B and ZEA standards in Chilean cereals with mass signals at m/z 355, 371, 337, and 317 for DON, NIV, 3-ADON and 15-ADON, and ZEA, respectively.

Enterocyte-Based Bioassay via Quantitative Combination of Proinflammatory Sentinels Specific to 8-keto-trichothecenes.

Type B 8-keto-trichothecenes are muco-active mycotoxins that exist as inevitable contaminants in cereal-based foodstuffs. Gut-associated inflammation is an early frontline response during human and animal exposure to these mycotoxins. Despite various tools for chemical identification, optimized biomonitoring of sentinel response-associated biomarkers is required to assess the specific proinflammatory actions of 8-keto-trichothecenes in the gut epithelial barrier. In the present study, intoxication with 8-keto-trichothecenes in human intestinal epithelial cells was found to trigger early response gene 1 product (EGR-1) that plays crucial roles in proinflammatory chemokine induction. In contrast, epithelial exposure to 8-keto-trichothecenes resulted in downregulated expression of nuclear factor NF-kappa-B p65 protein, a key transcription factor, during general inflammatory responses in the gut. Based on the early molecular patterns of expression, the inflammation-inducing activity of 8-keto-trichothecenes was quantified using intestinal epithelial cells with dual reporters for EGR-1 and p65 proteins. EGR-1-responsive elements were linked to luciferase reporter while p65 promoter was bound to secretory alkaline phosphatase (SEAP) reporter. In response to conventional inflammagens such as endotoxins and cytokines such as TNF-α, both luciferase and SEAP activity were elevated in a dose-dependent manner. However, as expected from the mechanistic evaluation, 8-keto-trichothecene-exposed dual reporters of luciferase and SEAP displayed contrasting expression patterns. Furthermore, 8-keto-trichothecene-elevated EGR-1-responsive luciferase activity was improved by deficiency of PSMA3, an α-type subunit of the 20S proteasome core complex for ubiquitin-dependent EGR-1 degradation. This molecular event-based dual biomonitoring in epithelial cells is a promising supplementary tool for detecting typical molecular inflammatory pathways in response to 8-keto-trichothecenes in the food matrix.

Genetic dereplication of Trichoderma hypoxylon reveals two novel polycyclic lactones.

Previous study demonstrated large scale production of trichochecenes which limited the discovery of novel metabolites in Trichoderma hypoxylon. By genetic deletion of trichothecene synthase encoding gene thtri5, we created the dereplication mutant which eliminated the production of trichothecenes. Through chemical isolation, we characterized a couple of rare new polycyclic lactones tricholactones A and B from the thtri5 deletion strain. The structures of these two compounds were well determined by NMR, HR-ESI-MS and IECD analysis.