FIG 2.

Effects of added nisin on L. lactis MG1363. (A) Growth curves after the addition of nisin to log-phase cultures at an OD₆₀₀ of ∼0.4, showing data for the Lactococcus host MG1363 parent strain (nisin sensitive), MG1363 harboring the base nisin-inducible vector (pMSP3535H3), and Lactococcus lactis ATCC 11454, a nisin-producing, naturally nisin-resistant L. lactis strain. Averages for three independent experiments are shown. (B) LIVE/DEAD BacLight assay showing the effects of increasing nisin concentrations on the membrane permeability of L. lactis MG1363 cells transformed with either the nisin-inducible vector (pMSP3535H3) or the vector with the full-length Cry5B insert (pTRK1068).