Figure 2. Megaplasmid Acquisition Decreases Resistance to 7-hydroxycoumarin and Nalidixic acid.

A) A dose response curve comparing bacterial growth (OD₆₀₀) of bacterial strains which contain (grey, DBL365) or lack (black, DBL332) the megaplasmid pMPPla107 across 7-hydroxycoumarin concentration. Curve is representative of at least 3 different assays. B) A dose response curve comparing bacterial growth (OD₆₀₀) of bacterial strains which contain (grey, DBL365) or lack (black, DBL332) the megaplasmid pMPPla107 across nalidixic acid concentration. Curve is representative of at least 3 different assays. C) Competitive fitness assays demonstrate that fitness of megaplasmid containing strains is significantly lower in 4 µg/mL nalidixic acid compared to 0 µg/mL (p = 0.046). Fitness is normalized so that P. stutzeri lacking the megaplasmid is 1, error bars show +2 standard errors in all cases.