The observed growth suppression effect of putrescine on the murine strain EcNC101 and the colorectal cancer–-isolated pks+ E. coli strain may be due to the positively charged potential of the molecule, which affects protein structure, function, interaction, and localization (40) and thus reduces the growth of pH-sensitive E. coli strains such as EcK12 (41). Here, ARAF is linked to colorectal cancer.