Effect of Ce3+ on membrane permeability of Escherichia coli cell

This study aimed to delineate the antibacterial mechanism of rare-earth ion Ce3+ to the target organism Escherichia coli cell, and the most important purpose was to identify its biological effect of increasing the E. coli cell membrane permeability. The antibacterial activities of Ce3+ to E. coli cells were tested, and then the permeability of outer membrane (OM) and inner membrane (IM) were studied by N-phenyl-1-naphthylamine (NPN) and o-nitrophenyl-β-D-galactopyranoside (ONPG) methods separately. Through these experiments we concluded that the E. coli cells grown to log phage were more sensitive to Ce3+ than the ones not at this stage; the structure of membrane was destroyed and the permeability of both OM and IM was obviously increased by Ce3+; there should be certain interactions between Ce3+ and some proteins inside the cell, which impeded the physiological activities of bacteria.