The cytology of yeasts

A history of research on yeasts 4: cytology part I, 1890–1950

“…McClary21 (151 p. 193) explains one ‘ …︁ difficulty of using …︁ stains for yeast cytology lies inthefact that the ratio of RNA to DNA in theyeastcell is something like 30 or 50:1, with the result that the nucleus is usually obscured by the densely stained cytoplasm.’ This difficulty explains why such a carefully critical scientist as Krasser22 was one of those who, in the 1880s and 1890s denied the existence of the yeast nucleus122, 123. The substance ‘nuclein’ had been discovered by Miescher23 in 1871153 and in 1880 Kossel24 had shown it to be a nucleoprotein: when nuclein was digested with pepsin, nucleic acids were liberated110, 121.…”