FIG 2.
Cometabolic conversion of AQs by Rhodococcus sp. BG43. (A and B) Cell suspensions of Rhodococcus sp. BG43 (OD600 ∼ 3) were incubated in modified KG medium with succinate and 20 μM PQS (A) or HHQ (B). The first culture sample was withdrawn and mixed with acidified ethyl acetate 3 min after AQ addition to the cells. The culture samples were extracted with ethyl acetate, and AQs and anthranilic acid in the extracts were quantified by HPLC. Squares, PQS; circles, anthranilic acid; triangles, HHQ. Filled symbols indicate substrates added to cultures, and open symbols indicate intermediates or products formed. Data represent mean values from three independent biological replicates ± standard deviations. (C) HPLC elution profiles of the conversion of an AQ preparation that besides HHQ (major peak at retention time, 39.1 min) additionally contains the trans and cis isomers of unsaturated HHQ (C7:1; at 37.9 min and 38.7 min, respectively), as well as long-chain AQs (C8-, C9-, C11-, and C13-AQ at 41.3, 43.2, 46.0, and 47.0 min) and the cis and trans isomers of their unsaturated congeners (C9:1, C11:1, C13:1; trans isomers have shorter retention times than the corresponding cis isomers [31]). PQS elutes at 40.2 min (90-min trace).