Extended Data Fig. 4: Protease secretion and in vitro biofilm dispersal.
a, Protease secretion by L. lactis NZ9000 upon nisin induction. Lane 1, protein ladder. Lane 2, control without protease secretion. Lane 3 and 4, Protease A. Lane 5 and 6, Protease B. Lane 7 and 8, Protease C. Black arrow indicates the band of Usp45. Red arrow indicates Protease A. Green arrow indicates Protease B. Blue arrow indicates Protease C. The absence of the Usp45 band in Lane 5–8 suggests that Proteases B and C both exhibit proteolytic activity to digest Usp45. b, Inhibition of the IS5 biofilm by the supernatants of the protease-secreting strains. Overnight culture of IS5 was diluted with fresh medium to the OD600 of 0.04, then 120 µl of the diluted culture was added to a cell culture treated 96-well plate. 30 µl of L. lactis NZ9000 supernatants containing different proteases were added into the IS5 culture. Biofilm thickness was measured after growth for 24 hours. Data are presented as mean ± s.d. from 3 independent experiments.
