Insight into the mechanism of action of temporin-SHa, a new broad-spectrum antiparasitic and antibacterial agent
Fig 4
Temporin-induced membrane permeabilization of E. coli ML-35p.
Bacteria were incubated with different concentrations of SHa (A) or [K3]SHa (B). The leakage kinetics were measured as the production of ONP at 405 nm resulting from hydrolysis of ONPG by the cytoplasmic bacterial β-galactosidase. C, comparison of the membrane leakage of temporins (SHa and [K3]SHa), dermaseptin B2 (B2) and melittin at the same concentration (10 μM). The negative control without peptide is also indicated (w/o peptide). D, no permeabilization was observed with [A2,6,9]SHa (2, 4, 6, 8 and 10 μM). E, Extracellular release of cytoplasmic β-galactosidase after 60 min incubation of bacteria with 10 μM peptide followed by centrifugation (1,000 x g, 10 min, 4°C) to measure ONP production (A405) in the supernatant. The results are expressed as the means ± SEM after subtraction of the negative control values (no peptide) from the test values and correspond to one representative experiment carried out in triplicate.