THE EFFECT OF FUMONISIN B-1 ON DEVELOPING CHICK-EMBRYOS - CORRELATIONBETWEEN DE-NOVO SPHINGOLIPID BIOSYNTHESIS AND GROSS MORPHOLOGICAL-CHANGES

Fumonisins, mycotoxins produced by Fusarium moniliforme and a number o f other fungi, are potent inhibitors of the sphinganine-N-acyltransfer ase, a key enzyme of sphingolipid biosynthesis, and cause neuronal deg eneration, liver and renal toxicity, cancer and other injury to animal s. In this study we investigated the effect of fumonisin B-1 on the sp hingolipids of developing chick embryos. After yolk sac injection of f umonisin B-1 a concentration and time dependent increase of the sphing anine-over-sphingosine ratio of the embryos could be demonstrated. Stu dies were done to evaluate the effect of fumonisin B-1 on the glycosph ingolipid pattern of the chick embryos. In the presence of 72 mu g fum onisin B-1 per egg the incorporation of [C-14]galactose and of [C-14]s erine into embryonic glycosphingolipids was reduced by about 70%, alth ough the mass of glycosphingolipids was not affected by the toxin. How ever, a reduction of the wet weight of the treated embryos was observe d. 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 treate d embyros. A close correlation between disruption of sphingoid metabol ism and light microscopic detectable tissue lesions could be observed.