Mouse Anti-Fumonisins Hybridoma [AB1]

Contamination of maize by fumonisin mycotoxins is of major concern to consumer health. This study was designed to improve our understanding of the binding of fumonisin B (FB) to maize and its major macrocomponents, during the preparation of porridge. None of the processing treatments (pH 4, 7 and 10) or temperatures (30 and 90 degrees C) used resulted in a significant decrease in the recovery of FB1 from spiked starch, zein or maize meal. These results confirm the stability of FB1 in maize porridge, and the absence of modified forms of FB. The bioaccessibility of fumonisins in the gastrointestinal tract, following consumption of contaminated stiff maize porridge, was determined using the TNO Gastrointestinal Model (tiny-TIM). The porridge was digested in the tiny-TIM using parameters simulating human digestion. The concentrations of fumonisins were determined in the dialysates at fixed time intervals using ultra performance liquid chromatography-quadrupole Time-ofFlight high definition mass spectrometry (UPLC-QToF-HDMS). The results proved that fumonisins B-1, B-2 and B-3 are released rapidly from stiff porridge prepared from contaminated maize meal. This confirms that the low bioavailability of fumonisins cannot be attributed to strong association of the toxin with the intestinal content. This study presents new insights into the stability of fumonisins in maize porridge and the kinetics of fumonisinrelease from porridge through simulated human digestion, suggesting that consumers using maize as a staple may be at risk.

It is now well established that sphingoid Long Chain Bases (LCBs) are crucial mediators of programmed cell death. In plants, the mycotoxin fumonisin B1 (FM) produced by the necrotrophic fungus Fusarium moniliforme disrupts the sphingolipid biosynthesis pathway by inhibiting the ceramide synthase leading to an increase in the amount of phytosphingosine (PHS) and dihydrosphingosine (DHS), the two major LCBs in Arabidopsis thaliana. To date, the signaling pathway involved in FB1-induced cell death remains largely uncharacterized. It is also well acknowledged that plant proteases such as papain-like cysteine protease are largely involved in plant immunity. Here, we show that the papain-like cysteine protease RD21 (responsive-to-desiccation-21) is activated in response to PHS and FB1 in Arabidopsis cultured cells and leaves, respectively. Using two allelic null mutants of RD21, and two different PCD bioassays, we demonstrate that the protein acts as a negative regulator of FB1-induced cell death in Arabidopsis.