Fig. 2

The AI-2 activity in BL21∆luxS. The wild strain BL21 secretes AI-2-like molecules, and can induce V. harveyi BB170 bioluminescence, whereas no bioluminescence induction was observed for the mutant BL21∆luxS. V. harveyi BB152 served as a positive control and E. coli DH5α as a negative control. The figure represents the means of the results from three independent experiments. The error bars indicate standard deviations