Fig 6.

Effects of the prc deletion on LPS, OMP, and MAC sensitivity of E. coli. (A) LPS of WT-RS218 and Δprc-RS218. The LPS samples derived from equal amounts of bacteria were analyzed by silver staining after separation by SDS-PAGE. (B) Silver-stained SDS-PAGE gels of OMPs of WT-RS218, Δprc-RS218, and pCL1920-prc-transformed Δprc-RS218 as well as of WT-RS218 bacteria grown with 300 μM the inhibitor peptide GRGYALAA. The arrow indicates a protein band close to 70 kDa that was differentially expressed in the OMs of Δprc-RS218 and WT-RS218 with or without inhibitor treatment. (C) WT-RS218 and Δprc-RS218 exhibited similar levels of MAC deposition after incubation in 80% and 10% NHS for 15 min (experimental group). The levels of MAC deposition were measured by flow cytometry and are presented as mean fluorescent intensities. The bacteria in the control group were stained with the nonspecific isotypic antibody of the corresponding primary antibody after incubation in NHS for 15 min. (D) Survival of WT-RS218 and Δprc-RS218 incubated in 80% and 10% NHS for 15 min. The results of serum survival are presented as relative survival rates compared to the survival rates of WT-RS218. All of the data shown are representative of three independent experiments performed in triplicate. The results are shown as the means ± standard deviations. *, P values of <0.05.