AAL toxins, fumonisins (biology and chemistry) and host-specificity concepts

The AAL toxins and the fumonisins (FB1 and FB2) are structurally related and produced respectively by Alternaria alternata f.sp. lycopersici and Fusarium moniliforme. AAL toxin is characterized as a host-specific toxin, toxic to tomato, whereas fumonisin B1 causes equine leukoencephalomalacia. FB1 and FB2 were biologically active in susceptible tomato tissue (Earlypak-7) and animal tissue culture (rat hepatoma H4TG and dog kidney MDCK). Conversely, AAL toxin was also active in the rat and dog tissue culture cells. Both fungi produce toxin/s in culture that causes death in rats; these toxins are other than AAL and fumonisin. The peracetylated derivatives of AAL and FB1 are biologically inactive in both the tomato bioassay and the animal tissue culture systems. Acetylation of the amine renders AAL inactive. The hydrolysis product of AAL (phentolamine) is toxic to the susceptible tomato line whereas the phentolamine of fumonisin is not. AAL and FB1 can be analyzed by Continuous Flow Fast Atom Bombardment (CFFAB) and Ionspray Mass Spectrometry (ISM), both sensitive to the picomole range. The N-acetyl of the TFA hydrolysis product of AAL and FB1 is determined by comparing the fragment ions at m/z 86 and 140 for FB1 and 72 and 126 for AAL.