TABLE 4.

Production of quorum-sensing-regulated metabolites by P. chlororaphis SPR044 and its TnMod derivatives^a

Strain	Protease productionb	PCA productionc	PCN productiond	Inhibition of gram-negative bacteriae	Inhibition of gram-positive bacteriaf
SPR044	+g	++	+	++	++
SPR144	−	−	−	−	−
SPR244	−	−	−	−	−
SPR344	+	+	+++	+	+
SPR544	+	++	−	+	+
SPR644	+	++	−	++	++
SPR744	+	−	−	+	+
SPR844	+	−	−	+	+

^aRepresentative data from four experiments are shown.

^bProtease activity was tested in well diffusion assays by using cell-free supernatants of stationary-phase cultures and agar supplemented with skim milk powder.

^cPCA production was measured by spectral analysis (200 to 500 nm) of chloroform extracts of cell-free supernatants.

^dPCN production was analyzed by visual estimation of the amount of green PCN crystals per colony.

^eA semiquantitative analysis was performed by using agar well diffusion assays with cell-free supernatants of stationary-phase cultures and cultures of C. violaceum.

^fA semiquantitative analysis was performed by using agar well diffusion assays with cell-free supernatants of stationary-phase cultures and cultures of B. subtilis.

^g+, present; −, absent. The number of plus signs indicates the production or inhibition compared to the production or inhibition by the wild type.