Nucleoprotein Layer of the Yeast Cell

ELECTRON microscopy of yeast has revealed nucleic acid in a space between the cell-wall and the plasma-membrane. Fig. 1 shows: ( a ) the thin, double-walled, convoluted, nucleic acid-free, plasma-membrane; ( b ) a region (occupying almost one-tenth the total cell volume) rich in nucleic acid which lies outside the plasma-membrane directly beneath the cell-wall. The dark stain of this layer, due to the uranyl acetate treatment, following permanganate fixation, shows that the layer contains nucleoprotein.