Fig 1.
Structure of D,L-N-acyl homoserine lactones.
R1 represents the substitution on the third position of the acyl chain and R2 represents the length of the acyl chain.
Table 1.
Abbreviations of N-acyl homoserine lactones used in this study.
Fig 2.
N-HLs detected in by LC-MS/MS and GC-MS/MS compared to N-HLs reported previously in the literature.
(A) P. atrosepticum and (B) P. aeruginosa. Sources of previously reported N-HLs referenced in Results and Discussions.
Fig 3.
LC-MS/MS chromatogram with MRM transition to m/z = 102 showing the separation of most prominent N-HLs.
(A) standard solution and (B) 123 h growth culture of P. atrosepticum. See Materials and methods section for details. Baselines normalized for clarity.
Fig 4.
LC-MS/MS chromatogram with MRM transition to m/z = 102 showing the separation of most prominent N-HLs.
(A) standard solution and (B) growth culture of P. aeruginosa. A-C4 and A-C6 were selected from 96 h growth and A-C8 and O-C12 were selected from 36 h growth. See method in experimental. Baselines normalized for clarity.
Fig 5.
Growth curves showing the OD 600 and production of N-HLs with respect to time in P. atrosepticum.
(A) D,L-O-C6 and (B) D,L-H-C6-HLs. Average of triplicates shown with standard deviations as error bars. Blue circle indicates the OD 600 reading with the measured values in the left y-axis. Red Square indicates the concentration of L-O-C6 (A) and L-H-C6 (B) with measured values in the right y-axis. Yellow triangle indicates the concentration of D-O-C6 (A) and D-H-C6 (B) with measured values in the right y-axis. Concentrations of D-O-C6 was increased by 100 times for clarity.
Fig 6.
Growth curves showing the OD 600 and production of with respect to time in P. aeruginosa.
(A) D,L-A-C4 and (B) D,L-A-C6-HLs. Average of triplicates shown with standard deviations as error bars. Blue circle indicates the OD 600 reading with the measured values in the left y-axis. Red square indicates the concentration of L-A-C4 (A) and L-A-C6 (B) with measured values in the right y-axis. Yellow triangle indicates the concentration of D-A-C4 (A) and D-A-C6 (B) with measured values in the right y-axis. Concentrations of D-A-C4 and D-A-C6 were increased by 10 times for clarity.
Table 2.
Maximum concentrations of each N-HL produced during the growth period quantified using LC-MS/MS.