Antimicrobial Assay of (ri)-(r)ApoB^Pro Peptide

The antimicrobial activity of (ri)-(r)ApoB_S^Pro peptide was assayed on methicillin-resistant S. aureus (MRSA WKZ-2), S. aureus ATCC 29213, E. coli ATCC 25922, and P. aeruginosa ATCC 27853 by using broth microdilution method. Bacteria were grown to the mid-logarithmic phase in MHB at 37 °C and then diluted to 4 × 10⁶ CFU/mL in Difco 0.5X nutrient broth (NB; Becton-Dickenson, Franklin Lakes, NJ, USA). To perform the assay, bacterial samples were mixed 1:1 v/v with two-fold serial dilutions of the peptidomimetic (0–40 µmol L⁻¹) and incubated for 20 h at 37 °C. Following the incubation, each sample was diluted and plated on TSA, in order to count the number of colonies [24 (link),25 ,26 (link)]. All the experiments were carried out as triplicates.