Fumonisins in infant cereals marketed as complementary food in Argentina.

Infant cereals are typically the first foods introduced as complementary foods. Cereals used to elaborate complementary foods, such as wheat, maize and rice, are susceptible to mycotoxin contamination. Among mycotoxins, fumonisins have been epidemiologically associated, in humans, with oesophageal cancer, neural tube defects and stunting. Fumonisins have been found in maize and wheat grains in Argentina. In the present study, a survey was conducted to determine their occurrence in 82 wheat-based and multicereal-based infant cereal items collected from retail stores in Rio Cuarto, Argentina, using HPLC-MS. Of these samples, 84% showed FBs contamination with levels ranging from 0.05 to 992 µg/kg). Although FB1 was the most prevalent fumonisin, FB2 was found at higher levels. Most samples had levels below the limit of 200 µg/kg set for Argentinean cereal products for children. The outcome of this survey provides information on the naturally presence of fumonisin in infant cereal intended for children in Argentina, which can be helpful to consider relevant monitoring programmes.

Volatilome of the maize phytopathogenic fungus Fusarium verticillioides: potential applications in diagnosis and biocontrol.

BACKGROUND: Fusarium verticillioides is a maize fungal phytopathogen and a producer of volatile organic compounds (VOCs) and fumonisin B1 (FB1). Our aim was to study the volatilome, conidial production, ergosterol and FB1 biosynthesis in maize cultures over a 30-day incubation period (5, 10, 15, 20, 25, 30 days post inoculation [DPI]). The effect of pure VOCs on the same parameters was then evaluated to study their potential role as biocontrol agents. RESULTS: In total, 91 VOCs were detected, with volatile profiles being more similar between 5 and 10 DPI compared with 15, 20, 25 and 30 DPI. Ergosterol content increased steadily with incubation time, and three growth stages were identified: a lag phase (0 to 15 DPI), an exponential phase (15 to 20 DPI) and a stationary phase (20 to 30 DPI). The maximum concentration of FB1 was detected at 25 (0.030 µg FB1/µg ergosterol) and 30 DPI (0.037 µg FB1/µg ergosterol), whereas conidial production showed a maximum value at 15 DPI (4.3 ± 0.2 × 105 conidia/µg ergosterol). Regarding pure VOCs, minimal inhibitory concentration values ranged from 0.3 mm for 4-hexen-3-one to 7.4 mm for 2-undecanone. Pure VOCs reduced radial growth, conidial production and ergosterol and FB1 biosynthesis. CONCLUSIONS: The marked resemblance between VOC profiles at 5 and 10 DPI suggests that they could act as early indicators of fungal contamination, particularly 4-ethylguaiacol, 4-ethyl-2-methoxyanisole, heptanol and heptyl acetate. On the other hand, their role as inhibitors of fungal growth and FB1 biosynthesis prove their great potential as safer alternatives to control phytopathogenic fungi. © 2024 Society of Chemical Industry.

Resistance of Transgenic Maize Cultivars to Mycotoxin Production-Systematic Review and Meta-Analysis.

Approximately 25% of cereal grains present with contamination caused by fungi and the presence of mycotoxins that may cause severe adverse effects when consumed. Maize has been genetically engineered to present different traits, such as fungal or insect resistance and herbicide tolerance. This systematic review compared the observable quantities, via meta-analysis, of four mycotoxins (aflatoxins-AFL, fumonisins-FUM, deoxynivalenol-DON, zearalenone-ZEA) between genetically modified (GM) and conventional maize kernels. This study was conducted following the PRISMA guidelines, with searches performed using PubMed, Web of Science, Scopus, Google Scholar, and CAPES journals databases. Analyses were conducted using RevMan v.5.4 software. Transgenic maize showed a 58% reduction in total mycotoxins (p < 0.001) compared to conventional maize. FUM were the most impacted, with a 59% reduction (p < 0.001) in GM maize. AFL and ZEA levels were also lower in GM maize by 49% (p = 0.02) and 51% (p < 0.001), respectively. On the other hand, DON levels increased by 6% (p < 0.001) in GM maize compared to conventional maize. However, results for ZEA and DON were inconclusive due to the limited research and sample sizes. We conclude that transgenic maize reduces total mycotoxins by over 50%, primarily fumonisin and aflatoxin. Most studies presented maize varieties that were resistant to insects or herbicides, not fungal pathogens, showing a positive collateral effect of these genetic alterations. Therefore, transgenic maize appears to be a safer product for animal and human consumption from a toxicological point of view. Further studies with larger sample sizes are needed to confirm our findings for ZEA and DON in transgenic maize.

Fungal Laccases and Fumonisin Decontamination in Co-Products of Bioethanol from Maize.

Maize (Zea mays L.) may be infected by Fusarium verticillioides and F. proliferatum, and consequently contaminated with fumonisins (FBs), as well as the co-products of bioethanol intended for animal feed. Laccase enzymes have a wide industrial application such as mycotoxin degradation. The aims were to isolate and identify fungal laccase-producing strains, to evaluate laccase production, to determine the enzymatic stability under fermentation conditions, and to analyse the effectiveness in vitro of enzymatic extracts (EEs) containing laccases in degrading FB1. Strains belonging to Funalia trogii, Phellinus tuberculosus, Pleurotus ostreatus, Pycnoporus sanguineus and Trametes gallica species showed laccase activity. Different isoforms of laccases were detected depending on the evaluated species. For the FB1 decontamination assays, four enzymatic activities (5, 10, 15 and 20 U/mL) were tested, in the absence and presence of vanillic acid (VA) and 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) as redox mediators (1 and 10 mM). Trametes gallica B4-IMICO-RC EE was the most effective strain in buffer, achieving a 60% of FB1 reduction. Laccases included in EEs remained stable at different alcoholic degrees in maize steep liquor (MSL), but no significant FB1 reduction was observed under the conditions evaluated using MSL. This study demonstrate that although laccases could be good candidates for the development of a strategy to reduce FB1, further studies are necessary to optimise this process in MSL.

Involvement of aryl hydrocarbon receptor in the aflatoxin B1 and fumonisin B1 effects on in vitro differentiation of murine regulatory-T and Th17 cells.

Aflatoxin B1 (AFB1) and fumonisin B1 (FB1) are mycotoxins widely found as cereal contaminants, and their co-consumption is associated with liver cancer. Both are immunotoxic, but their interactions have been little studied. This work was aimed to evaluate in mouse spleen mononuclear cells (SMC) the effects of the exposure to AFB1 (5-50 µM), FB1 (25-250 µM), and AFB1-FB1 mixtures (MIX) on the in vitro differentiation of regulatory T cells (Treg and Tr1-like) and Th17 cells, as well as elucidate the contribution of aryl hydrocarbon receptor (Ahr) in such effects. AFB1 and mainly MIX induced cytotoxicity in activated CD4 cells via Ahr signaling. AFB1 (5 µM) increased the Treg cell differentiation, but its combination with FB1 (25 µM) also reduced Th17 cell expansion by Ahr-dependent mechanisms. Therefore, this mixture could enhance the Treg/Th17 cell ratio and favor immunosuppression and escape from tumor immunosurveillance to a greater extent than individual mycotoxins. Whereas, AFB1-FB1 mixtures at medium-high doses inhibited the Tr1-like cell expansion induced by the individual mycotoxins and affected Treg and Th17 cell differentiation in Ahr-independent and dependent manners, respectively, which could alter anti-inflammatory and Th17 immune responses. Moreover, individual FB1 altered regulatory T and Th17 cell development independently of Ahr. In conclusion, AFB1 and FB1 interact by modifying Ahr signaling, which is involved in the immunotoxicity as well as in the alteration of the differentiation of Treg, Tr1-like, and Th17 cells induced by AFB1-FB1 mixtures. Therefore, Ahr is implicated in the regulation of the anti- and pro-inflammatory responses caused by the combination of AFB1 and FB1.

Fusarium Species and Mycotoxins Associated with Sorghum Grains in Uruguay.

Grain mold and stalk rot are among the fungal diseases that cause significant losses in sorghum worldwide and are caused by different Fusarium spp. The presence of Fusarium species in sorghum grains causes yield losses and mycotoxin contamination, which represents a risk to consumers. In this study, Fusarium graminearum species complex (FGSC) had a high incidence, followed by Fusarium fujikuroi species complex (FFSC) and F. incarnatum-equiseti species complex. Within FFSC, F. proliferatum, F. andiyazi, F. fujikuroi, F. thapsinum, F. verticillioides and F. subglutinans were identified, and this was the first report of F. fujikuroi in sorghum. The most frequent toxins found in sorghum samples were deoxynivalenol (DON) and zearalenone (ZEN). The presence of fumonisins and nivalenol (NIV) was detected at low levels. This study adds new knowledge about the occurrence of Fusarium species and mycotoxins in sorghum grains. Furthermore, this is the first report in Uruguay on fungicide sensitivity for Fusarium isolates from sorghum, which constitutes an important starting point for defining management practices to minimize fungal infection and mycotoxin contamination.

A two-year study on the occurrence and concentration of mycotoxins in corn varieties with different endosperm textures.

BACKGROUND: Mycotoxin monitoring in cereal grains has great importance in the food and feed industries. This study evaluated mycotoxin contamination in corns with different endosperm textures in 2 years of cultivation. Samples of dent, semi-dent, flint and semi-flint corns from field experiments were analyzed by high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). RESULTS: Occurrences of fumonisins B1 (FB1 ) and B2 (FB2 ) in 2020 were 45.72% (mean 270 µg kg-1 ) and 35.89% (94.97 µg kg-1 ), respectively, and 68.98% (446 µg kg-1 ) and 45.83% (152 µg kg-1 ) in 2021. Occurrence of aflatoxin B1 was 11.96% (0.16 µg kg-1 ) in 2020 and 11.11% (0.13 µg kg-1 ) in 2021. In 2020, deoxynivalenol (DON) and zearalenona (ZEA) presented occurrences of 1.28% and 1.70%, with means of 4.08 and 2.45 µg kg-1 , respectively. In 2021, results were 8.33% (31.00 µg kg-1 ) for DON and 8.79% (4.38 µg kg-1 ) for ZEA. Citrinin, diacetoxyscirpenol and fusarenon-X did not occur in 2020 but presented 1.66%, 0.83%, and 2.50% positive rates in 2021, respectively. In 2020, flint corn presented the lowest concentration of FB1 whereas dent corn presented the highest concentration of FB1 and FB2 (P < 0.05). In 2021, dent corn presented the highest means of FB1 , FB2 and diacetoxyscirpenol (P < 0.05). Dent and semi-dent presented the highest concentration of nivalenol (P < 0.05). CONCLUSION: The endosperm texture influenced mycotoxin contamination in corn grains, especially FB1 and FB2 , which had the highest concentration in dent corn in the 2 years of this study. © 2023 Society of Chemical Industry.

Alphatoxin Nanopore Detection of Aflatoxin, Ochratoxin and Fumonisin in Aqueous Solution.

Mycotoxins are toxic and carcinogenic metabolites produced by groups of filamentous fungi that colonize food crops. Aflatoxin B1 (AFB1), ochratoxin A (OTA) and fumonisin B1 (FB1) are among the most relevant agricultural mycotoxins, as they can induce various toxic processes in humans and animals. To detect AFB1, OTA and FB1 in the most varied matrices, chromatographic and immunological methods are primarily used; however, these techniques are time-consuming and expensive. In this study, we demonstrate that unitary alphatoxin nanopore can be used to detect and differentiate these mycotoxins in aqueous solution. The presence of AFB1, OTA or FB1 inside the nanopore induces reversible blockage of the ionic current flowing through the nanopore, with distinct characteristics of blockage that are unique to each of the three toxins. The process of discrimination is based on the residual current ratio calculation and analysis of the residence time of each mycotoxin inside the unitary nanopore. Using a single alphatoxin nanopore, the mycotoxins could be detected at the nanomolar level, indicating that alphatoxin nanopore is a promising molecular tool for discriminatory analysis of mycotoxins in aqueous solution.

Sphingolipid Long-Chain Base Signaling in Compatible and Non-Compatible Plant-Pathogen Interactions in Arabidopsis.

The chemical diversity of sphingolipids in plants allows the assignment of specific roles to special molecular species. These roles include NaCl receptors for glycosylinositolphosphoceramides or second messengers for long-chain bases (LCBs), free or in their acylated forms. Such signaling function has been associated with plant immunity, with an apparent connection to mitogen-activated protein kinase 6 (MPK6) and reactive oxygen species (ROS). This work used in planta assays with mutants and fumonisin B1 (FB1) to generate varying levels of endogenous sphingolipids. This was complemented with in planta pathogenicity tests using virulent and avirulent Pseudomonas syringae strains. Our results indicate that the surge of specific free LCBs and ceramides induced by FB1 or an avirulent strain trigger a biphasic ROS production. The first transient phase is partially produced by NADPH oxidase, and the second is sustained and is related to programmed cell death. MPK6 acts downstream of LCB buildup and upstream of late ROS and is required to selectively inhibit the growth of the avirulent but not the virulent strain. Altogether, these results provide evidence that a LCB- MPK6- ROS signaling pathway contributes differentially to the two forms of immunity described in plants, upregulating the defense scheme of a non-compatible interaction.

In Search of Resistance Against Fusarium Ear Rot: Ferulic Acid Contents in Maize Pericarp Are Associated With Antifungal Activity and Inhibition of Fumonisin Production.

Fusarium verticillioides is a fungal pathogen of maize that causes seedling blight, stem rot, and Fusarium ear rot. Fungal infestation of maize kernels and ears affects grain quality from the ensuing mycotoxin buildup. Among the mycotoxins produced by F. verticillioides, fumonisins accumulate to high levels in Fusarium-infected maize kernels, fumonisin B1 (FB1) being the most abundant in naturally infected maize. Achieving resistance to Fusarium ear rot has been challenging, as various environmental factors facilitate fungal infection. Among the maize grain components that contribute to resistance to F. verticillioides infection, the pericarp is the first barrier faced by the fungus and thus plays a key role. Phenolic acids are major constituents of maize pericarp, of which ferulic acid (FA) is the predominant molecular species. In this work, we explored the relationship between FA levels, fungal infection, and FB1 production in 51 maize genotypes and whether the antioxidant activity of FA might play a role. We confirmed that FA is a major component of the seed pericarp, whose levels as bound FA varied between 4.5 and 26.3 mg/g across maize genotypes. We selected two pools of five maize varieties, with contrasting FA contents: low FA (LFA; 6.14 ± 0.40 mg/g) and high FA (HFA; 15.49 ± 1.31 mg/g). In vitro, HFA extracts inhibited fungal growth with effects comparable to FA concentrations in the 0.25-0.50 mM range. We also established a kernel assay to study F. verticillioides colonization and FB1 production in the LFA and HFA genotypes. Fungal colonization was significantly lower in HFA genotypes relative to LFA genotypes, based on ergosterol levels. Moreover, FB1 production was also inhibited in the HFA genotypes. Importantly, the antioxidant activity of maize pericarp extracts was associated with FA contents, with HFA extracts exhibiting a greater antioxidant activity than LFA extracts. Overall, our results highlight the role of FA and its antioxidant activity on resistance to Fusarium ear rot and provide the basis of a phenotypic trait that can be deployed for breeding selection.

Effect of adsorbents on diets with corn contaminated by mycotoxins on the productive performance and health of broilers / Effect of adsorbents on diets with corn contaminated by mycotoxins on the productive performance and health of broilers

A total of 1,296 broiler chicken were housed, distributed in a completely randomized design with 6 treatments and 6 repetitions. The treatments consisted of a control diet formulated with corn considered adequate and without the addition of adsorbent, a diet formulated with corn naturally contaminated with mycotoxin (CCM) and four diets formulated with CCM and added with different commercial adsorbents. At the end of the first week and at 21 days of age of the birds, it was observed that the control diet resulted in greater (p < 0.05) live weight and weight gain in relation to the inclusion of CCM. The relative weight of the liver was lower for the control group compared to the groups receiving a diet with CCM and CCM + ads D. The relative weight of the proventriculus and cloacal bursa was lower for the control group compared to those who received a diet with CCM + ads B and CCM + ads C. There was no significant effect (p > 0.05) of the diets on the analysis of serum biochemistry and the occurrence of fatty and hydropic degeneration in the liver of broilers. The use of adsorbents can mitigate the harmful effects of mycotoxins, however, these products have specific binding capacity to the type of mycotoxin present in food.

A total of 1,296 broiler chicken were housed, distributed in a completely randomized design with 6 treatments and 6 repetitions. The treatments consisted of a control diet formulated with corn considered adequate and without the addition of adsorbent, a diet formulated with corn naturally contaminated with mycotoxin (CCM) and four diets formulated with CCM and added with different commercial adsorbents. At the end of the first week and at 21 days of age of the birds, it was observed that the control diet resulted in greater (p < 0.05) live weight and weight gain in relation to the inclusion of CCM. The relative weight of the liver was lower for the control group compared to the groups receiving a diet with CCM and CCM + ads D. The relative weight of the proventriculus and cloacal bursa was lower for the control group compared to those who received a diet with CCM + ads B and CCM + ads C. There was no significant effect (p > 0.05) of the diets on the analysis of serum biochemistry and the occurrence of fatty and hydropic degeneration in the liver of broilers. The use of adsorbents can mitigate the harmful effects of mycotoxins, however, these products have specific binding capacity to the type of mycotoxin present in food.

Effect of adsorbents on diets with corn contaminated by mycotoxins on the productive performance and health of broilers

A total of 1,296 broiler chicken were housed, distributed in a completely randomized design with 6 treatments and 6 repetitions. The treatments consisted of a control diet formulated with corn considered adequate and without the addition of adsorbent, a diet formulated with corn naturally contaminated with mycotoxin (CCM) and four diets formulated with CCM and added with different commercial adsorbents. At the end of the first week and at 21 days of age of the birds, it was observed that the control diet resulted in greater (p < 0.05) live weight and weight gain in relation to the inclusion of CCM. The relative weight of the liver was lower for the control group compared to the groups receiving a diet with CCM and CCM + ads D. The relative weight of the proventriculus and cloacal bursa was lower for the control group compared to those who received a diet with CCM + ads B and CCM + ads C. There was no significant effect (p > 0.05) of the diets on the analysis of serum biochemistry and the occurrence of fatty and hydropic degeneration in the liver of broilers. The use of adsorbents can mitigate the harmful effects of mycotoxins, however, these products have specific binding capacity to the type of mycotoxin present in food.(AU)

Effect of adsorbents on diets with corn contaminated by mycotoxins on the productive performance and health of broilers

A total of 1,296 broiler chicken were housed, distributed in a completely randomized design with 6 treatments and 6 repetitions. The treatments consisted of a control diet formulated with corn considered adequate and without the addition of adsorbent, a diet formulated with corn naturally contaminated with mycotoxin (CCM) and four diets formulated with CCM and added with different commercial adsorbents. At the end of the first week and at 21 days of age of the birds, it was observed that the control diet resulted in greater (p < 0.05) live weight and weight gain in relation to the inclusion of CCM. The relative weight of the liver was lower for the control group compared to the groups receiving a diet with CCM and CCM + ads D. The relative weight of the proventriculus and cloacal bursa was lower for the control group compared to those who received a diet with CCM + ads B and CCM+ ads C. There was no significant effect (p > 0.05) of the diets on the analysis of serum biochemistry and the occurrence of fatty and hydropic degeneration in the liver of broilers. The use of adsorbents can mitigate the harmful effects of mycotoxins, however, these products have specific binding capacity to the type of mycotoxin present in food.(AU)

Effect of adsorbents on diets with corn contaminated by mycotoxins on the productive performance and health of broilers / Effect of adsorbents on diets with corn contaminated by mycotoxins on the productive performance and health of broilers

A total of 1,296 broiler chicken were housed, distributed in a completely randomized design with 6 treatments and 6 repetitions. The treatments consisted of a control diet formulated with corn considered adequate and without the addition of adsorbent, a diet formulated with corn naturally contaminated with mycotoxin (CCM) and four diets formulated with CCM and added with different commercial adsorbents. At the end of the first week and at 21 days of age of the birds, it was observed that the control diet resulted in greater (p < 0.05) live weight and weight gain in relation to the inclusion of CCM. The relative weight of the liver was lower for the control group compared to the groups receiving a diet with CCM and CCM + ads D. The relative weight of the proventriculus and cloacal bursa was lower for the control group compared to those who received a diet with CCM + ads B and CCM + ads C. There was no significant effect (p > 0.05) of the diets on the analysis of serum biochemistry and the occurrence of fatty and hydropic degeneration in the liver of broilers. The use of adsorbents can mitigate the harmful effects of mycotoxins, however, these products have specific binding capacity to the type of mycotoxin present in food.

A total of 1,296 broiler chicken were housed, distributed in a completely randomized design with 6 treatments and 6 repetitions. The treatments consisted of a control diet formulated with corn considered adequate and without the addition of adsorbent, a diet formulated with corn naturally contaminated with mycotoxin (CCM) and four diets formulated with CCM and added with different commercial adsorbents. At the end of the first week and at 21 days of age of the birds, it was observed that the control diet resulted in greater (p < 0.05) live weight and weight gain in relation to the inclusion of CCM. The relative weight of the liver was lower for the control group compared to the groups receiving a diet with CCM and CCM + ads D. The relative weight of the proventriculus and cloacal bursa was lower for the control group compared to those who received a diet with CCM + ads B and CCM + ads C. There was no significant effect (p > 0.05) of the diets on the analysis of serum biochemistry and the occurrence of fatty and hydropic degeneration in the liver of broilers. The use of adsorbents can mitigate the harmful effects of mycotoxins, however, these products have specific binding capacity to the type of mycotoxin present in food.

Evaluation of aflatoxin and fumonisin co-exposure in urine samples from healthy volunteers in northern Mexico.

Aflatoxins (AF) and fumonisins (FB) are common contaminants of maize and have been associated with cancer, immune suppression, and growth stunting. In this work, AFM1 and FB1 were measured in urine samples of healthy volunteers from the metropolitan area of Monterrey, Mexico, while AF and FB were detected in foods collected near the sampling zone. Urine samples from 106 adults were analyzed using ultra-performance liquid chromatography-tandem mass spectrometry and toxins in foods were measured by fluorometry. The mean value of AFM1 and FB1 was 4.3 pg/mg creatinine from 76 samples (72 %), and 50 pg/mg creatinine from 75 samples (71 %), respectively. More than half of the samples (n = 56, 53 %) had detectable levels of both AFM1 and FB1. No differences in toxin levels were found between males and females or between age groups, but AFM1 and FB1 levels were higher (p < 0.01) when detected as a single exposure compared to co-exposed. Some significant results were found when comparing AFM1 and FB1 levels among groups of people assigned to levels of food consumption. Food samples had average concentrations of 5.3 µg/kg for AF and 800 µg/kg for FB. The results showed that co-exposure to AF and FB is common in the metropolitan area of Monterrey.

Protective effects of silymarin in broiler feed contaminated by mycotoxins: growth performance, meat antioxidant status, and fatty acid profiles.

The aim of this study was to determine whether the inclusion of silymarin in broiler feed was able to mitigate the adverse effects of mycotoxin on growth performance, health status, liver oxidative stress, and meat fatty acid profiles. A completely randomized design with four treatments, four repetitions, and 15 chicks per repetition was used, with the following groups: (a) feed without additives (NoMyc-NoSil), (b) feed supplemented with silymarin (NoMyc-Sil), (c) feed contaminated with mycotoxin (Myc-NoSil), and (d) feed contaminated with mycotoxin and supplemented with silymarin (Myc-Sil). Growth performance, intestinal and liver health, and meat quality were assessed. The consumption of feed contaminated with mycotoxin delayed weight gain and increased the feed conversion ratio; however, the addition of silymarin prevented these adverse effects on the chicken industry. Serum ALT activity was higher in Myc-NoSil broilers than in other groups. Intake of silymarin in healthy birds increased serum globulin concentration and reduced albumin concentration and ALT and AST serum activities compared to the Myc-NoSil group. The NoMyc-Sil birds had greater villus heights and crypt depths. Luminosity and water loss by cooking were affected by mycotoxin ingestion, changes that did not occur in the meat of birds that were supplemented with silymarin. The sum of saturated and monounsaturated fatty acids in the meat did not change among treatments, unlike the sum of polyunsaturated fatty acids higher in the meat of birds that consumed silymarin. We conclude that silymarin is a potential additive in broiler feed; it reduces impairment of growth performance at the end of the productive cycle, prevents oxidative stress, improves meat quality, and increases polyunsaturated fatty acids.

Molecular and Environmental Triggering Factors of Pathogenicity of Fusarium oxysporum and F. solani Isolates Involved in the Coffee Corky-Root Disease.

Coffee corky-root disease causes serious damages to coffee crop and is linked to combined infection of Fusarium spp. and root-knot nematodes Meloidogyne spp. In this study, 70 Fusarium isolates were collected from both roots of healthy coffee plants and with corky-root disease symptoms. A phylogenetic analysis, and the detection of pathogenicity SIX genes and toxigenicity Fum genes was performed for 59 F. oxysporum and 11 F. solani isolates. Based on the molecular characterization, seven F. oxysporum and three F. solani isolates were assessed for their pathogenicity on coffee seedlings under optimal watering and water stress miming root-knot nematode effect on plants. Our results revealed that a drastic increment of plant colonization capacity and pathogenicity on coffee plants of some Fusarium isolates was caused by water stress. The pathogenicity on coffee of F. solani linked to coffee corky-root disease and the presence of SIX genes in this species were demonstrated for the first time. Our study provides evidence for understanding the pathogenic basis of F. oxysporum and F. solani isolates on coffee and revealed the presence of SIX and Fum genes as one of their pathogenicity-related mechanisms. We also highlight the relevance of chlorophyll, a fluorescence as an early and high-throughput phenotyping tool in Fusarium pathogenicity studies on coffee.

Stability of fumonisin B1 and its bioaccessibility in extruded corn-based products.

Fumonisins are a group of mycotoxins commonly associated with corn-based products and require innovative alternatives to control exposure to its toxicity. The objective of this research was to determine the effect of amylose and resistant starch on fumonisin B1 (FB1) levels in extruded corn-based products as well as the toxin bioaccessibility upon digestion. Cornmeal contaminated with FB1 (1.5 µg/g) was extruded alone or combined with high-amylose corn starch (20%, w/w). FB1 was quantified both in the unextruded and extruded products by HPLC (high-performance liquid chromatography) fluorescence detector with pre-column derivatization. Samples were then subjected to an in vitro digestion model to evaluate the stability of the interaction between FB1 and the corn matrix extruded. The addition of high-amylose corn starch further reduced the detection of FB1 (74.9%), when compared with the effect of the extrusion alone (66.0%), confirming the binding of FB1 with the macromolecules or resistant starch. The bound fumonisin was stable upon simulated gastric digestion, and the duodenal bioaccessibility of free FB1 was lower than 35% when high-amylose corn starch ingredient was used in the product. Principal component analysis (PCA) showed that high-amylose corn starch and resistant starch content influenced the reduction of FB1 and its duodenal bioaccessibility. This study for the first time shows that addition of high-amylose corn starch during extrusion is an innovative strategy to reduce FB1 release under digestive conditions, therefore useful in mitigating the exposure to this mycotoxin.

Molecular analysis of Aspergillus section Nigri isolated from onion samples reveals the prevalence of A. welwitschiae.

The aim of this study was to isolate Aspergillus section Nigri from onion samples bought in supermarkets and to analyze the fungal isolates by means of molecular data in order to differentiate A. niger and A. welwitschiae species from the other non-toxigenic species of black aspergilli, and detect genes involved in the biosynthesis of ochratoxin A and fumonisin B2. Aspergillus section Nigri were found in 98% (94/96) of the onion samples. Based on the results of multiplex PCR (performed on 500 randomly selected strains), 97.4% of the Aspergillus section Nigri strains were recognized as A. niger/A. welwitschiae. Around half of them were subjected to partial sequencing of the CaM gene to distinguish one from the other. A total of 97.9% of the isolates were identified as A. welwitschiae and only 2.1% as A. niger. The fum8 gene, involved in fumonisin B2 biosynthesis, was found in 36% of A. welwitschiae isolates, but radH and pks genes, involved in ochratoxin A biosynthesis, were found in only 2.8%. The presence/absence of fum8 gene in the A. welwitschiae genome is closely associated with ability/inability of the isolates to produce fumonisin in vitro. Based on these results, we suggest that in-depth studies are conducted to investigate the presence of fumonisins in onion bulbs.

Cytoprotective effects of curcumin and silymarin on PK-15 cells exposed to ochratoxin A, fumonisin B1 and deoxynivalenol.

Mycotoxins are toxic secondary metabolites produced by fungus which cause worldwide concern regarding food and feed safety. Ochratoxin A (OTA), fumonisin B1 (FB1) and deoxynivalenol (DON) are some of the main mycotoxins and oxidative stress is the main mechanism of toxicity. Thereby, this study investigates the in vitro cytoprotective effects of curcumin (CUR) and silymarin (SIL) - known for their strong antioxidant activity - in PK-15 cells exposed to OTA, FB1 and DON. Pretreatment with CUR and SIL enhanced the viability of cells exposed to the mycotoxins (P < 0.001) and attenuated reactive oxygen species (ROS) formation by DON (P < 0.01), partially reduced ROS formation by FB1 (P < 0.001), but not OTA. CUR significantly decreased apoptosis in cells exposed to DON (P < 0.01) but was not able to prevent apoptosis in cells exposed to OTA and FB1. Whereas SIL was able to prevent apoptosis in PK-15 cells exposed to FB1 and DON (P < 0.01) but was not able to decrease apoptosis in cells exposed to OTA. In summary, these data indicate that curcumin and silymarin are able to provide cytoprotection against toxicity induced by OTA, FB1 and DON in PK-15 cells.