ornithine nonhuman 10 polyamine 8 priority journal 8 article 6 controlled study 6 enzyme activity 6 ornithine decarboxylase 6 putrescine 6 spermidine 6 Bacteria (microorganisms) 4 Escherichia coli 4 Trypanosoma cruzi 4 arginine 4 bacterium mutant 4 biosynthesis 4 eflornithine 4 growth rate 4 Amino acid transport 2 Arginine kinase 2 Bacterial Proteins 2 Canavanine 2 Cell Fractionation 2 Cell Membrane 2 Chagas disease 2 Chlorophyll 2 Chromatography, Thin Layer 2 Comparative Study 2 Culture Media 2 Electrophoresis 2