EFFECTS OF FUMONISIN B-1 ON OXYGEN-TRANSPORT IN MEMBRANES

Electron spin resonance (ESR) spin-label oximetry has been used to stu dy the effects of fumonisin B-1 (FB1), a sphingoid-like mycotoxin, on oxygen transport in phosphatidylcholine (PC) bilayers. Moreover, the u se of spin labels attached to different carbons of fatty acids makes i t possible to do structural and oximetric determinations with the same test sample. Specifically, the incorporation of 10 mol% FB1 increased the oxygen transport properties of both saturated and unsaturated mem branes at 37 degrees C by ca. 30% and decreased the ordering of the hy drocarbon chains near the surface of the membranes; concomitantly, oxy gen transport near the center of bilayers was diminished slightly, and the relative oxygen diffusion-concentration product profile curves we re markedly flattened. (C) 1996 Academic Press, Inc.