Distribution of acid ribonuclease and other enzymes in stratified Acetabularia.

A method for producing stratified and viable subcells, consisting of segments of the stalk, has been worked out in Acetabularia mediterranea (LmX). Centrifugation at low speed results in the formation of a cytoplasmic moiety at the centrifugal pole which contains ca. 90% of the aldolase activity that is localized in the chloroplasts and in the cytosol. The vacuolar moiety, which occupies 80-92% of the cell volume, stains with neutral red, i.e. is viable. It contains ca. 76% of the total RNase and 72% of the total phosphotase activity. It is concluded that a large proportion of these hydrolase activities is present in the vacuole.