Fig 1.
Increasing concentration of the antimicrobial peptide Melittin increases bacterial membrane permeability to propidium iodide.
(a) Schematic representation of the work flow for determining MIC, MBC and MDC. (b) Flow cytometry dot blots of F. nucleatum incubated with increasing concentrations of Melittin and stained with Syto9 dye (membrane permeable) and propidium iodide dye (membrane impermeable). (c) Percent propidium iodide positive F. nucleatum cells correlates with increasing peptide concentration. Insert shows the reciprocal plot of percent membrane disrupted cells (PI+) and peptide concentration to determine MDC.
Table 1.
MIC and MBC of melittin for F. nucleatum and S. mutans and comparison with the membrane disrupting concentration (MDC) determined at different peptide/bacteria incubation times.
Table 2.
Comparison of the antimicrobial activity of three defined pore forming peptides and a membrane lytic peptide determined by microdilution growth assay (MIC), colony count assay (MBC) and the flow cytometry assay (MDC) for Gram positive and Gram negative bacteria.
Fig 2.
Flow cytometry dot plots of F. nucleatum and S. mutans incubated with magainin analogues at a concentration equivalent to the MIC50 concentration of magainin.
Cells stained with Syto9 dye (membrane permeable) and propidium iodide dye (membrane impermeable).
Table 3.
Antimicrobial activity of Magainin analogues against S. mutans, and F. nucleatum.