Regulation of antimicrobial activity and xenocoumacins biosynthesis by pH in Xenorhabdus nematophila

Table 5 The relative amount of xenocoumacins (Xcn1 and Xcn2) in methanol extract of the cell-free filtrate of X. neamatophila YL001 at pH 5.5, 7.0 and 8.5

¹The relative amount of Xcn1 (the molecular ion [M+H]⁺, 466 m/z) and Xcn2 (the molecular ion [M+H]⁺, 407 m/z) in methanol extract of the cell-free filtrate of X. neamatophila YL001 at different pH were determinated by ESI-HPLC–MS (See Additional file 1: Figures S9–S11). Relative amount of Xcns = [the peak area of extracted ion chromatograms (EIC) of Xcns at different pH/the peak area of extracted ion chromatograms (EIC) of Xcns at pH 8.5] × 100. The relative amount of Xcns at pH 8.5 refers to 100. Different lower case letters followed by the data of Xcn1 and Xcn2 at different pH indicate significant differences at P = 0.05

ISSN: 1475-2859