Fig. 3

a β-Galactosidase activity of the strain NTL4 of A. tumefaciens incubated with different N-AHLs and using the ONPG substrate; values indicate relative absorbance from measurements at 420 nm relative to the cellular growth at 600 nm. Gray bars represent samples incubated with the GqqA protein and black bars with BSA as a control. Error bars represent standard deviations. Data are mean values of at least three measurements. b Motility tests performed on swarming agar with the strain PAO1 of P. aeruginosa transformed with pBBR1MCS-5::gqqA and the re-circularized vector pBBR1MCS-5. c Pyocyanin production of the strain PAO1 transformed with pBBR1MCS-5::gqqA and pBBR1MCS-5 empty vector, values of relative absorbance from measurements at 520 nm relative to the cellular growth at 600 nm. Error bars represent standard deviations. Data are mean values of at least three measurements. d Difference in violacein production by the strain Cv026 of C. violaceum using different concentrations of C6-HSL in the presence of the GqqA protein and BSA (15 µg/ml), shown in triplicate. Relative quantification of the violacein produced under different conditions measured by the absorbance at 575 nm relative to the cellular growth at 600 nm. Gray bars represent samples incubated with the GqqA protein and black bars with BSA as a control. Error bars represent standard deviation. Data are mean values of at least three measurements