Synthesis of RNA,Protein, Cellulose,and Mucopolysaccharide and Changes in the Chemical Composition of Hartmannella culbertsoni During Encystment under Axenic Conditions*

Hartmannella culbertsoni trophozoites are transformed into viable cysts on exposure to a non-nutrient agar medium containing 15 mM MgCl₂ and 20 mM taurine. Amebae differentiating in this encystment medium incorporate more uracil-2-¹⁴C into RNA and more leucine-1-¹⁴C or valine-1-¹⁴C into proteins than controls. Encysting organisms incorporate significantly more glucose-U-¹⁴C into cellulose and glucosamine-1-¹⁴C into mucopolysaccharides. Incorporation of glucose-U-¹⁴C into cellulose and of glucosamine-1-¹⁴C into mucopolysaccharides are inhibited by actinomycin D or cycloheximide.