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International audience; NX and its acetylated form 3ANX are two new type A trichothecenes produced by Fusarium graminearum whose toxicity is poorly documented. The aim of this study was to obtain a general view of the intestinal toxicity of these toxins. Deoxynivalenol (DON), which differs from NX by the keto group at C8, served as a benchmark. The viability of human intestinal Caco-2 cells decreased after 24 h of exposure to 3 μM NX (−21.4%), 3 μM DON (−20.2%) or 10 μM 3ANX (−17.4%). Histological observations of porcine jejunal explants exposed for 4 h to 10 μM of the different toxins showed interstitial edema and cellular debris. Explants exposed to NX also displayed cell vacuolization, a broken epithelial barrier and high loss of villi. Whole transcriptome profiling revealed that NX, DON and 3ANX modulated 369, 146 and 55 genes, respectively. Functional analyses indicated that the three toxins regulate the same gene networks and signaling pathways mainly; cell proliferation, differentiation, apoptosis and growth, and particularly immune and pro-inflammatory responses. Greater transcriptional impacts were observed with NX than with DON. In conclusion, our data revealed that the three toxins have similar impacts on the intestine but of different magnitude: NX > DON ≫ 3ANX. NX and 3ANX should consequently be included in overall risk analysis linked to the presence of trichothecenes in our diet.

Fusarium chaquense, a recently formally described novel species, has been identified as an T-2 toxin (T-2), HT-2 toxin (HT-2) and other toxins producer in natural grasses (Poaceae) from Argentina. The major objective of this study was to describe the effect of water activity (aW, 0.995, 0.98, 0.95, 0.93 and 0.91), temperature (15, 25 and 30◦ C) and incubation time (5, 15 and 25 days) on growth and to evaluate the production of T-2, HT-2 toxins and beauvericin (BEA) by two F. chaquense strains in a grass-based media. The results showed a wide range of conditions for F. chaquense growth and mycotoxin production. Both strains had a maximum growth rate at the highest aW (0.995) and 25◦C. Regarding mycotoxin production, more T-2 than the other analysed mycotoxins were produced by the two strains. T-2 production was favoured at 0.995 aW and 30◦C, while HT-2 production at 0.98–0.95 aW and 15◦ C. The maximum levels of BEA were produced at 0.995 aW and 25–30◦ C. Two-dimensional profiles of aW by temperature interactions were obtained from these data in order to identify areas where conditions indicate a significant risk of mycotoxins accumulation on grass. For its versatility on growth and mycotoxin production in a wide range of aW and temperatures, F. chaquense would have an adaptive advantage over other Fusarium species, and this would explain its high frequency of isolation in natural grasses grown up in the Chaco wetlands. Fil: Nichea, Maria Julia. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigación en Micología y Micotoxicología. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación en Micología y Micotoxicología; Argentina Fil: Cendoya, Eugenia. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigación en Micología y Micotoxicología. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación en Micología y Micotoxicología; Argentina Fil: Haidukowski, Miriam. Institute of Sciences of Food Production; Italia. Consiglio Nazionale delle Ricerche; Italia Fil: Torres, Adriana Mabel. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigación en Micología y Micotoxicología. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación en Micología y Micotoxicología; Argentina Fil: Ramirez, Maria Laura. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigación en Micología y Micotoxicología. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigación en Micología y Micotoxicología; Argentina

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.