An Improved Method of Preparing High Efficiency Transformation Escherichia coli with Both Plasmids and Larger DNA Fragments

摘要

The effect of LFcin-B on the competence of DH5α. The survival of DH5α grow on LB medium plate with different imicrobial peptides. Three common imicrobial peptides Cecropin A, PR-39 and LFcin-B were added in LB medium plate in normal concentration (0.5 mg/mL). LB medium plate was as control. DH5α strains were grow in these plates overnight at 37°C and then observed, calculated and photographed. LFcin-B increase the permeability of inner and outer cell membrane determined by NPN assay and ONPG assay. The increase of LFcin-B decreased the transformation efficiency of DH5α. Different concentration of MnCl and CaCl effect the antibacterial property of LFcin-B. Slight concentration of LFcin-B (0.35 mg/L) were added in Inoue method transformation buffer with gradient concentration of MnCl and CaCl , and then calculated the transformation efficiency of DH5α competent cells made by these TB with Inoue method. Each data had three repeats and the bar indicated the SE