Fig. 4.

Lactocin 160, much like nisin, completely dissipated the transmembrane pH gradient (ΔpH) in G. vaginalis. Initially, the cells loaded with BCECF-AM were energized with 2.2 mmol l⁻¹ glucose (Glu). Two μmol l⁻¹ valinomycin (Val) was then used to convert the ΔΨ component of the PMF into ΔpH. Decrease in fluorescence intensity following the addition of lactocin 160 (Lac160, a), or nisin (Nis, b), indicate that these antimicrobials dissipate transmembrane pH gradient in G. vaginalis. Nisin diluent and lactic acid solutions, respectively, were used as the corresponding negative controls (Control−). Finally, 2 μmol l⁻¹ nigericin (Nig) was used to completely collapse any residual ΔpH