QUANTIFICATION OF THE EFFECT OF SUBSTRATE CONCENTRATION ON THE CONJUGAL TRANSFER RATE OF THE TOL PLASMID IN SHORT-TERM BATCH MATING EXPERIMENTS

Batch mating experiments with Pseudomonas putida PAW 1 (TOL) as a dono r and Pseudomonas aeruginosa PAO 1162 as a recipient strain were perfo rmed to quantify the effect of the substrate concentration in the mati ng medium on the observed plasmid transfer rate coefficient, The impac t of the substrate concentration in the mating medium was highly corre lated with the growth history of the donor strain, When the donor stra in was harvested in exponential growth phase, no impact was observed; when the donor strain was taken from the stationary phase, however, a strong impact of the substrate concentration was measured: a 10-fold r eduction in the substrate concentration decreased the observed plasmid transfer rate by 55%.