Antibacterial activities and membrane permeability actions of glycinin basic peptide against Escherichia coli

摘要

The objective of this study was to determine the antibacterial characteristics of glycinin basic peptide (GBP) and its effects on the cell membrane of Escherichia colt (E. coli). The antibacterial activities of GBP increased with increasing GBP concentrations and treatment times. Atomic force microscope analysis showed that GBP damaged the morphology of E. coli cells. GBP significantly (p <0.05) increased the permeability of the outer membrane of E. coli cells treated with 80 mu g/ml GBP, thereby enhancing the sensitivity of E. coli cells to erythromycin and rifampicin. Moreover, O-nitrophenyl-beta-D-galactopyranoside (ONPG) entered into bacterial cells and immediately reacted with beta-galactosidase in the cells due to the destruction of the inner membrane of E. coli. The damage to the bacterial membrane caused by GBP resulted in Ca2+, K+, and Mg2+ leakage from the cells. SDS-PAGE of the membrane proteins further demonstrated that GBP significantly destroyed the cell membrane and promoted the extraction of membrane proteins in the presence of Triton X-114.