Fig. 4

Mutagenesis of amilCP to create different-colored markers with the same fitness effects in competition assays. a Positions C64 and Q65 of amilCP (GFP numbering; Table 1) in pSB1K3 plasmid were mutagenized randomly and different-colored bacterial colonies (results not shown) were chosen for streaking on an LB kanamycin plate. b Double integrants were made of each of three amilCP variants from a, as well as of spisPink and aeBlue, and their fitness effects were measured by direct competition in LB medium with isogenic wild-type E. coli. Analysis was by plating and counting of colored versus white colonies. Selection coefficients with negative values show that the expression confers a fitness cost for the cells. Error bars are standard deviations