Fig. 2.
(a) Reverse-phase (RP)-TLC analysis of AHLs from KLH11 and QS mutants. TLC plate was overlaid with the A. tumefaciens ultrasensitive AHL reporter strain (Zhu et al., 2003). Organic extracts of cultures of strain OKC6 containing vector pSRKTc (Khan et al., 2008) were used as negative control. The concentration of X-Gal in the agar was 40 µg ml−1. (b, c) MS analysis of purified samples. The products of reverse-phase chromatographic separation of AHLs extracted and purified from (b) OKC6 (ΔssaI ΔssbI sscI−) and (c) OKC6 (ΔssaI ΔssbI sscI−/Plac-sscI) were examined using the precursor ion-scanning mode (transitions were monitored for precursor [M+H]+, →m/z 102.1). The peaks in the chromatograms are labelled with upper-case lettering and include the AHLs noted and as described by Zan et al. (2012).