Detection of AHLs with biosensor strains.

<p><i>P</i>.<i>a</i> indicates <i>Pectobacterium atrosepticum 6276</i> strain, which produces C_8- NAHLs, used as positive control. <i>P</i>.<i>aΔexp1</i> means <i>Pectobacterium atrosepticum</i> 6276 mutant strain, which does not produce AHLs, used as negative control. <b>A.</b> Detection of short-chain AHLs with <i>Chromobacterium violaceum</i> CV026 (CV026). CV026 indicates <i>C</i>.<i>violaceum CV026</i> strain, which produces vioalacein in contact with C₄-C₈ NAHLs, used as biosensor strain. Black arrow indicates violacein production by <i>C</i>.<i>violaceum CV026</i> strain. LB plates were incubated for 72 h at 37°C (<i>n</i> = 3). <b>B.</b> Detection of long-chain AHLs with <i>Agrobacterium tumefaciens</i> NTI (ANTI1). ANT1 means <i>Agrobacterium tumefaciens</i> NT1 strain, which produces β-galactosidase in contact with C₆-C₁₂ NAHLs, used as biosensor strain. Red arrow indicates β-galactosidase production by <i>Agrobacterium tumefaciens</i> strain. LB plates containing X-Gal (40 μg/mL) were incubated for 72 h at 28°C (<i>n</i> = 3).