Open field study of some Zea mays hybrids, lipid compounds and fumonisins accumulation

Lipid molecules are increasingly recognized as signals exchanged by organisms interacting in pathogenic and/or symbiotic ways. Some classes of lipids actively determine the fate of the interactions. Host cuticle/cell wall/membrane components such as sphingolipids and oxylipins may contribute to determining the fate of host–pathogen interactions. In the present field study, we considered the relationship between specific sphingolipids and oxylipins of different hybrids of Zea mays and fumonisin by F. verticillioides, sampling ears at different growth stages from early dough to fully ripe. The amount of total and free fumonisin differed significantly between hybrids and increased significantly with maize ripening. Oxylipins and phytoceramides changed significantly within the hybrids and decreased with kernel maturation, starting from physiological maturity. Although the correlation between fumonisin accumulation and plant lipid profile is certain, the data collected so far cannot define a cause-effect relationship but open up new perspectives. Therefore, the question—“Does fumonisin alter plant lipidome or does plant lipidome modulate fumonisin accumulation?”—is still open

The low intestinal and hepatic toxicity of hydrolyzed fumonisin B1 correlates with its inability to alter the metabolism of sphingolipids

Fumonisins are mycotoxins frequently found as natural contaminants in maize, where they are produced by the plant pathogen Fusarium verticillioides. They are toxic to animals and exert their effects through mechanisms involving disruption of sphingolipid metabolism.Fumonisin B1 (FB1) is the predominant fumonisins in this family. FB1 is converted to its hydrolyzed analogs HFB1, by alkaline cooking (nixtamalization) or through enzymatic degradation. The toxicity of HFB1 is poorly documented especially at the intestinal level. The objectives of this study were to compare the toxicity of HFB1 and FB1 and to assess the ability of these toxins to disrupt sphingolipids biosynthesis. HFB1 was obtained by a deesterification of FB1, with a carboxylesterase. Piglets, animals highly sensitive to FB1, were exposed by gavage for 2 weeks to 2.8 µmol FB1 or HFB1/kg body weight/day. FB1 induced hepatotoxicity as indicated by the lesion score, the level of several biochemical analytes and the expression of inflammatory cytokines. Similarly, FB1 impaired the morphology of the different section of the small intestine, reduced villi height and modified intestinal cytokine expression. By contrast, HFB1 did not trigger hepatotoxicity, did not impair intestinal morphology and slightly modified the intestinal immune response. This low toxicity of HFB1 correlates with a weak alteration of the sphinganine/sphingosine ratio in the liver and in the plasma. Taken together, these data demonstrate that HFB1 does not cause intestinal or hepatic toxicity in the sensitive pig model, and slightly disrupts sphingolipids metabolism. This finding suggests that conversion to HFB1 could be a good strategy to reduce FB1 exposure

Fumonisin B1 contamination of cereals and risk of esophageal cancer in a high risk area in Northeastern Iran

Introduction: Fumonisin B1 (FB1) is a toxic and carcinogenic mycotoxin produced in cereals due to fungal infection. This study was conducted to determine FB1 contamination of rice and corn samples and its relationship with the rate of esophageal cancer (EC) in a high risk area in northeastern Iran. Methods: In total, 66 rice and 66 corn samples were collected from 22 geographical subdivisions of Golestan province of Iran. The levels of FB1 were measured for each subdivision by thin layer and high pressure liquid chromatographies. The mean level of FB1 and the proportions of FB1 contaminated samples were compared between low and high EC-risk areas of the province. Results: The mean of FB1 levels in corn and rice samples were 223.64 and 21.59 μ/g, respectively. FB1 contamination was found in 50% and 40.9% of corn and rice samples, respectively. FB1 level was significantly higher in rice samples obtained from high EC-risk area (43.8 μ/g) than those obtained from low risk area (8.93 μ/g) (p-value=0.01). The proportion of FBI contaminated rice samples was also significantly greater in high (75%) than low (21.4%) EC-risk areas (p-value=0.02). Conclusion: We found high levels of FBI contamination in corn and rice samples from Golestan province of Iran, with a significant positive relationship between FB1 contamination in rice and the risk of EC. Therefore, fumonisin contamination in commonly used staple foods, especially rice, may be considered as a potential risk factor for EC in this high risk region

Effects of elevated [CO2 ] on maize defence against mycotoxigenic Fusarium verticillioides.

Maize is by quantity the most important C4 cereal crop; however, future climate changes are expected to increase maize susceptibility to mycotoxigenic fungal pathogens and reduce productivity. While rising atmospheric [CO2 ] is a driving force behind the warmer temperatures and drought, which aggravate fungal disease and mycotoxin accumulation, our understanding of how elevated [CO2 ] will effect maize defences against such pathogens is limited. Here we report that elevated [CO2 ] increases maize susceptibility to Fusarium verticillioides proliferation, while mycotoxin levels are unaltered. Fumonisin production is not proportional to the increase in F. verticillioides biomass, and the amount of fumonisin produced per unit pathogen is reduced at elevated [CO2 ]. Following F. verticillioides stalk inoculation, the accumulation of sugars, free fatty acids, lipoxygenase (LOX) transcripts, phytohormones and downstream phytoalexins is dampened in maize grown at elevated [CO2 ]. The attenuation of maize 13-LOXs and jasmonic acid production correlates with reduced terpenoid phytoalexins and increased susceptibility. Furthermore, the attenuated induction of 9-LOXs, which have been suggested to stimulate mycotoxin biosynthesis, is consistent with reduced fumonisin per unit fungal biomass at elevated [CO2 ]. Our findings suggest that elevated [CO2 ] will compromise maize LOX-dependent signalling, which will influence the interactions between maize and mycotoxigenic fungi

Effects of four Fusarium toxins (fumonisin B(1), alpha-zearalenol, nivalenol and deoxynivalenol) on porcine whole-blood cellular proliferation.

The in vitro effects of four Fusarium toxins, fumonisin B1 (FB1), a-zearalenol (a-ZEA), nivalenol (NIV) and deoxynivalenol (DON), on mitogen-induced cell proliferation were determined in swine whole-blood cultures. Considering the lack of sufficient toxicological data both on single and in combination effects, in vitro studies may contribute to risk assessment of these toxins. Incubation with increasing concentrations of FB1 did not produce any consequence on proliferation; in contrast a-ZEA, NIV and DON showed an inhibitory effect. Dose–response curves for each mycotoxin were generated. NIV was found to be the most potent toxin followed by DON and a-ZEA. The effects of both FB1 þ a-ZEA and NIVþ DON mixtures were also analysed to investigate possible interactions. The results indicated that combination of FB1þ a-ZEA produces a synergistic inhibition of porcine cell proliferation; whereas there is no interaction between DON and NIV on porcine wholeblood proliferation, at tested concentrations

Production and purification of fumonisins from a highly toxigenic Fusarium verticilloides strain

Fumonisins are the major mycotoxins produced by Fusarium verticilloides and F. proliferatum fungi which are widely found as contaminants in corn and corn screenings. These molecules are hepatotoxic and nephrotoxic for several species and carcinogenic in rodents. Moreover their consumption was linked to high prevalence of human oesophageal cancer in certain geographic areas. The aim of this work was to improve FB1 production and purification procedures in laboratory conditions in order to produce large quantities of semi-purified toxin that may be used in experimental intoxications of farm animals. We used a highly toxigenic strain of Fusarium verticilloides (NRRL-3428) isolated from feeds. Influence of substrate, temperature, water content, culture recipient size and screen analysis of the substrate on fumonisin production was tested. Optimal production was obtained when strain was grown on coarsely cracked corn with 50% water content at 21°C during 5 weeks. This allowed the production of 3 to 4 g of fumonisin B1 per kg of culture material. The composition of the extracts was found to be as follow : 54% FB1, 8% FB2, 9% FB3 and 29% of pigments coming from corn. The ratio observed between FB1 and FB2 is comparable to the one reported in naturally contaminated corn. Further purification of these extracts on SAX columns led to the removal of pigments and to obtain of fumonisins extracts pure enough to be used for intra-venous or intra-peritoneal injection

Integrating gene expression, ecology and mycotoxin production by Fusarium and Aspergillus species in relation to interacting environmental factors

Environmental factors, such as water availability (water activity, aw), temperature and their interactions, have a significant impact on the life cycle of mycotoxigenic fungi. Growth and mycotoxin production are influenced by these interacting factors resulting in a broader range of aw × temperature conditions for germination, than growth or mycotoxin production. The biosynthetic genes are mostly clustered together and by using microarrays with sub-arrays for specific mycotoxins, such as trichothecenes, fumonisins and aflatoxins it has been possible to examine the relationship between interacting aw × temperature conditions on growth, toxin gene cluster expression and relate these to phenotypic toxin production. The data for groups of biosynthetic genes (Fusarium culmorum/Fusarium graminearum; Fusarium verticillioides; Aspergillus flavus) were integrated with data on growth and mycotoxin production under different aw × temperature conditions using a mixed growth model. This was used to correlate these factors and predict toxin levels which may be produced under different abiotic stress conditions. Indeed, the relative importance of the different genes could be examined using ternary diagrams of the relative expression of 3 genes at a time in relation to aw, temperature and mycotoxin production to identify the most important relationships. The effect of three-way interacting environmental factors representative of climate change (CC) scenarios (water stress × temperature (+2-4 °C) × elevated CO2 (350-400 vs 650 and 1000 ppm) on growth and mycotoxin production by A. flavus and by species of the Aspergillus section Circumdati and section Nigri have been determined. These studies on maize grain and coffee, respectively, suggest that while growth may not be significantly affected, mycotoxin production may be stimulated by CC factors. This approach to integrate such data sets and model the relationships could be a powerful tool for predicting the relative toxin production under extreme stress conditions, including CC scenarios

Toxicokinetics of fumonisin B1 in turkey poults and tissue persistence after exposure to a diet containing the maximum European tolerance for fumonisins in avian feeds

The kinetic of fumonisin B1 (FB1) after a single IV and oral dose, and FB1 persistence in tissue were investigated in turkey poults by HPLC after purification of samples on columns. After IV administration (single-dose: 10 mg FB1/kg bw), serum concentration–time curves were best described by a three-compartment open model. Elimination half-life and mean residence time of FB1 were 85 and 52 min, respectively. After oral administration (single-dose: 100 mg FB1/kg bw) bioavailability was 3.2%; elimination half-life and mean residence time were 214 and 408 min, respectively. Clearance of FB1 was 7.6 and 7.5 ml/min/kg for IV and oral administration respectively. Twenty four hours after the administration of FB1 by the intravenous route, liver and kidney contained the highest levels of FB1 in tissues, level in muscle was low or below the limit of detection (LD, 13 µg/kg). The persistence of FB1 in tissue was also studied after administration for nine weeks of a feed that contained 5, 10 and 20 mg FB1+FB2/kg diet. Eight hours after the last intake of 20 mg FB1+FB2/kg feed (maximum recommended concentration of fumonisins established by the EU for avian feed), hepatic and renal FB1 concentrations were 119 and 22 µg/kg, level in muscles was below the LD