Dry mass, lipid content and protein content of the intact and zona-free mouse ovum

Abstract

ABSTRACT Intact and zona-free single-celled mouse ova were analyzed for total protein and were dried and weighed on a quartz fiber fishpole balance before and after lipid extraction. The zona pellucida was found to contribute 19 per cent, of the dry mass of the intact ovum. It was estimated to be 96 per cent, water and 4 per cent, solid matter, of which 30 per cent, was protein. No statistically significant amount of lipid was found. The cytoplasm was estimated to be 85 per cent, water and 15 per cent, solid matter, of which 12·5 per cent, was lipid and 71 per cent, protein. The lipid content was no greater than that of protoplasm from other sources, indicating the presence of only a small amount of yolk. The cytoplasm was found to be less variable in mass than the zona pellucida.