Figure 2.

Antimicrobial potency of PaTx-II was tested against bacteria for 24 h at 37 °C. (A–D) Minimum inhibitory concentrations (MICs) were determined by standard procedures (see Methods). The inhibitory effect of PaTx-II was shown against S. aureus (MICs 25 µM), P. vulgaris (MICs 28 µM), P. mirabilis (MICs 35 µM) and E. aerogenes (MICs 25 µM); svPLA₂ shows the most potent inhibitory effect at the lowest dilutions. (E,F) Ultrastructural (scanning and transmission electron microscope) micrographs reveal that the PaTx-II-treated (MIC, 25 µM) bacteria show membrane blebs (mb), cell roughening (cr), debris (d), release of cellular contents (rc), wrinkled surfaces (ws), thickened cell walls (tcw), membrane damage (md) and cell death (cd) at the septal region after 24 h at 37 °C. Untreated normal cells (nc, insets) show none of these features.