Effects of fumonisin B1 on oxygen transport in membranes.

Electron spin resonance (ESR) spin-label oximetry has been used to study the effects of fumonisin B1 (FB1), a sphingoid-like mycotoxin, on oxygen transport in phosphatidylcholine (PC) bilayers. Moreover, the use of spin labels attached to different carbons of fatty acids makes it 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 membranes at 37 degrees C by ca. 30% and decreased the ordering of the hydrocarbon chains near the surface of the membranes; concomitantly, oxygen transport near the center of bilayers was diminished slightly, and the relative oxygen diffusion-concentration product profile curves were markedly flattened.