Putrescine Escherichia coli Ribosomes in vitro study putrescine article escherichia coli CULTURA Cell Division Kinetics Mutation Support, Non-U.S. Gov't Translation, Genetic polyamine spermidine ANTROPOLOGIA ANTROPOLOGIA CULTURAL Y SOCIAL Bacterial Proteins HOMBRE SOCIOLOGIA animal experiment auxotrophic mutant microorganism protein synthesis radioisotope ribosome theoretical study (E. coli) 13C-NMR ANTROPOLOGIA SOCIAL