Efficiencies of transfer of ICEBs1 (kanamycin-resistant) from the indicated donor strains into the recipient CAL419 (streptomycin-resistant) were calculated from the number of kanamycin-resistant, streptomycin-resistant trans-conjugants per initial donor X 100%.
A. Wild type (CAL1173), recF (CAL1174), recF pcrA (CAL1175), and recF pcrA +pcrA (CAL1148) donors were grown in minimal L-arabinose medium at 30°C and expression of RapI (Pxyl-rapI) was induced by addition of xylose for 2 hours. Mating mixtures were incubated at 37°C for 3 hours. Gray bars show the average and standard deviation from two independent mating assays. The asterisk indicates that the mating efficiency of the recF pcrA double mutant was <0.0001%.
B. Wild type (JMA168), dnaCts (CAL1035), and dnaNts (CAL1161) donors were grown in minimal L-arabinose medium at 30°C. A portion was shifted to 47°C for 5 minutes, and then IPTG was added to all donor cultures at 30°C and 47°C for 90 minutes to induce expression of RapI (Pspank(hy)-rapI). Mating mixtures were incubated at 30°C or 47°C for 3 hours. Speckled (30°C) and black (47°C) bars show the average and standard deviation from two to four independent mating experiments.