The Effect of Thiosemicarbazide and other Urea Analogues on the Growth of Tetrahymena geleii

Summary: A number of urea analogues have been tested for inhibitory effects on the growth of Tetrahymena geleii. Semicarbazide and thiosemicarbazide appear to interfere with the formation of compounds containing carbonyl-groups. The inhibition can be partially overcome by increasing the concentration of pyridoxamine in the medium or completely overcome by adding keto-acids. The thiosemicarbazones of β- and γ-pyridine carboxaldehyde and of p-acetaminobenzal are inhibitory but reversal of this inhibition was not possible with the compounds used.