Effect of Ce3＋ on membrane permeability ofEscherichia coli cell

This study aimed to delineate the antibacterial mechanism of rare-earth ion Ce3＋ to the target organism Escherichia coil cell, and the most important purpose was to identify its biological effect of increasing the E. coli cell membrane permeability. The antibacterial activi- ties 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-l-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.