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Toxins (Basel) ; 15(4)2023 03 28.
Artigo em Inglês | MEDLINE | ID: mdl-37104186


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.

Fusarium , Micotoxinas , Toxina T-2 , Tricotecenos do Tipo B , Zearalenona , Micotoxinas/análise , Avena/microbiologia , Grão Comestível/química , Zearalenona/análise , Cromatografia Líquida , Contaminação de Alimentos/análise , Espectrometria de Massas em Tandem , Toxina T-2/análise , Escócia , Glucosídeos
Toxins (Basel) ; 12(10)2020 10 13.
Artigo em Inglês | MEDLINE | ID: mdl-33066173


Mycotoxins are important food contaminants that commonly co-occur with modified mycotoxins such as mycotoxin-glucosides in contaminated cereal grains. These masked mycotoxins are less toxic, but their breakdown and release of unconjugated mycotoxins has been shown by mixed gut microbiota of humans and animals. The role of different bacteria in hydrolysing mycotoxin-glucosides is unknown, and this study therefore investigated fourteen strains of human gut bacteria for their ability to break down masked mycotoxins. Individual bacterial strains were incubated anaerobically with masked mycotoxins (deoxynivalenol-3-ß-glucoside, DON-Glc; nivalenol-3-ß-glucoside, NIV-Glc; HT-2-ß-glucoside, HT-2-Glc; diacetoxyscirpenol-α-glucoside, DAS-Glc), or unconjugated mycotoxins (DON, NIV, HT-2, T-2, and DAS) for up to 48 h. Bacterial growth, hydrolysis of mycotoxin-glucosides and further metabolism of mycotoxins were assessed. We found no impact of any mycotoxin on bacterial growth. We have demonstrated that Butyrivibrio fibrisolvens, Roseburia intestinalis and Eubacterium rectale hydrolyse DON-Glc, HT-2 Glc, and NIV-Glc efficiently and have confirmed this activity in Bifidobacterium adolescentis and Lactiplantibacillus plantarum (DON-Glc only). Prevotella copri and B. fibrisolvens efficiently de-acetylated T-2 and DAS, but none of the bacteria were capable of de-epoxydation or hydrolysis of α-glucosides. In summary we have identified key bacteria involved in hydrolysing mycotoxin-glucosides and de-acetylating type A trichothecenes in the human gut.

Bactérias/enzimologia , Proteínas de Bactérias/metabolismo , Microbioma Gastrointestinal , Intestinos/microbiologia , Micotoxinas/metabolismo , Acetilação , Bactérias/classificação , Bactérias/crescimento & desenvolvimento , Microbiologia de Alimentos , Glucosídeos/metabolismo , Humanos , Hidrólise , Micotoxinas/efeitos adversos , Medição de Risco , Especificidade por Substrato , Fatores de Tempo , Tricotecenos/metabolismo
Int J Food Sci Nutr ; 71(5): 540-548, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31791183


Fusarium mycotoxins are common contaminants in cereals and often co-occur with plant-derived mycotoxin sugar conjugates. Several of these modified mycotoxins are not degraded in the small intestine and hence carried through to the large intestine where microbial transformation may occur. This study aims to assess the gastrointestinal stability of the trichothecenes HT-2 toxin (HT-2), HT-2-ß-glucoside (HT-2-Glc), diacetoxyscirpenol (DAS), DAS-α-glucoside (DAS-Glc) and fumonisin B1 (FB1), N-(1-deoxy-d-fructos-1-yl) fumonisin-B1 (NDF-FB1). All tested modified mycotoxins were stable under upper gastrointestinal (GI) conditions. In faecal batch culture experiments, HT-2-Glc was hydrolysed efficiently and no further microbial biotransformation of HT-2 was observed. DAS-Glc hydrolysis was slow and DAS was de-acetylated to 15-monoacetoxyscripenol. NDF-FB1 was hydrolysed at the slowest rate and FB1 accumulation varied between donor samples. Our results demonstrate that all tested modified mycotoxins are stable in the upper GI tract and efficiently hydrolysed by human gut microbiota, thus potentially contributing to colonic toxicity. Hence the microbial biotransformation of any novel modified mycotoxins needs to be carefully evaluated.

Grão Comestível/química , Fumonisinas/metabolismo , Fusarium , Microbioma Gastrointestinal , Glucosídeos/metabolismo , Intestino Grosso , Tricotecenos/metabolismo , Adulto , Biotransformação , Feminino , Contaminação de Alimentos , Trânsito Gastrointestinal , Humanos , Hidrólise , Intestino Grosso/metabolismo , Intestino Grosso/microbiologia , Intestino Delgado/metabolismo , Masculino , Micotoxinas Mascaradas/metabolismo , Pessoa de Meia-Idade , Micotoxinas/metabolismo , Poaceae , Toxina T-2/análogos & derivados , Toxina T-2/metabolismo , Trato Gastrointestinal Superior/metabolismo