Sequential deletion of three genes ( phzH , phzM and phzS ) and the HPLC analysis of phenazine derivatives in P. aeruginosa cultured media. (A). PCR detection results of strain PAO1 and strain PCA. Lane 1 was DNA marker (Takara 1 kb marker, from 1.0 kb to 10.0 kb). Lanes 2, 4, 6 showed the PCR products with the PAO1 genome DNA as template, and lanes 3, 5, 7 showed those using the PCA genome DNA as template. Lanes 2 and 3, 4 and 5, 6 and 7 corresponded to PCR fragments obtained from the pair primers phzH-DF and phzH-DR, phzM-DF and phzM-DR, phzS-DF and phzS-DR, accordingly. (B). The HPLC results of the extracted phenazine derivatives from the cultured media of P. aeruginosa PAO1 (a) and P. aeruginosa PCA (b). The retention times were shown on the tops. MS was used to identify each fraction collected between the pink lines under the peak. Their chemical identities were PCA (9.17 min-10.43 min), PYO (13.42 min-13.93 min), PCN (18.34 min-18.97 min), and 1-OH-Phz (20.42 min-20.93 min). Four phenazine derivates were detected in the cultured media of strain PAO1, while only PCA was detected in those of PCA strain.