FACTORS AFFECTING PROTEIN SYNTHESIS IN HYMENOLEPIS DIMINUTA (CESTODA)

1. 1. The cestode, Hymenolepis diminuta, incorporated C14-labeled amino acids from the ambient medium into protein. The amino acids tested were incorporated at rates which did not correspond directly to the apparent internal concentration of the amino acid. The incorporation rate of lysine-C14 was linear during a 2-hr incubation period. 2. 2. Starvation produced a depression in the corporation of lysine-C14. Preincubation of starved worms in glucose slightly stimulated the incorporation whereas 3-0-methylglucose produced no stimulation. 3. 3. The presence of CO2 caused a marked stimulation of lysine-C14 incorporation in both starved and unstarved worms. The presence of glucose in the preincubation medium further enhanced this stimulation in starved worms. 4. 4. Incubation with 2,4-dinitrophenol inhibited the incorporation of lysine-C14 by per cent. DNP abolished the stimulatory effects of CO2 and glucose on lysine-C14 incorporation in starved worms, substantiating the central role of CO2 in energy metabolism of the worm. 5. 5. Galactose stimulated lysine-C14 incorporation, but was not as effective as glucose. 6. 6. The significance of CO2 and glucose in the metabolism of the parasite is discussed. © 1969.