Ergosterol films

In 1934 Danielli and Adam (37), pointed out that the area occupied in the surface by an ergosterol molecule was decidedly unfavorable to the proposed position 4 for the hydroxyl group, as had been suggested in the same year by Rosenheim and King. Danielli and Adam showed that films of ergosterol and its irradiation products occupied a much greater area when spread on dilute permanganate solution than when... 

The actual value of the dipole moment was always considerably higher than that of the unoxidized monolayers, the largest increase (300%) being observed with lumisterol films. Tachysterol was not oxidized by permanganate at these concentrations, and the dinitrobenzoates of ergosterol and calciferol were decidedly more resistant to oxidation than the sterols themselves, probably due to steric hindrance by the large dinitrobenzoyl group. 

These polyenes injure fungi by binding to the ergosterol and sitosterol of the plasma membranes (Hamilton-Miller, 1973). Mycoplasma laidlawii was unaffected by filipin when grown in the absence of the sterol, but lysed when grown in its presence (Weber and Kinsky, 1965). When polyene antibiotics were injected under mixed lipids, present as a monolayer in a surface-trough, it was found that the polyene interpenetrated the film and increased its area. Reorientation of the sterol component, caused by interaction with the polyene, seemed to make the film leaky (Demel, Van Deenen and Kinsky, 1965). Mitochondrial and nuclear membranes are not affected by the polyenes, nor is the cell wall (Kinsky, 1962). 

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