The effect of fumonisin B-1 on developing chick embryos: Correlation between de novo sphingolipid biosynthesis and gross morphological changes

Fumonisins, mycotoxins produced by Fusarium moniliforme and a number of other fungi, are potent inhibitors of the sphinganine-N-acyltransferase, a key enzyme of sphingolipid biosynthesis, and cause neuronal degeneration, liver and renal toxicity, cancer and other injury to animals. In this study we investigated the effect of fumonisin B-1 on the sphingolipids of developing chick embryos. After yolk sac injection of fumonisin B-1 a concentration and time dependent increase of the sphinganine-over-sphingosine ratio of the embryos could be demonstrated. Studies were done to evaluate the effect of fumonisin B-1 on the glycosphingolipid pattern of the chick embryos. In the presence of 72 mu g fumonisin B-1 per egg the incorporation of [C-14]galactose and of [C-14]serine into embryonic glycosphingolipids was reduced by about 70%, although the mass of glycosphingolipids was not affected by the toxin. However, a reduction of the wet weight of the treated embryos was observed. Additionally, histological examinations of whole embryo sections of control and fumonisin B-1 treated embryos are presented. Fumonisin B-1 caused haemorrhages under the skin as well as in the liver of treated embyros. A close correlation between disruption of sphingoid metabolism and light microscopic detectable tissue lesions could be observed.