Figure 1. Kinetics of natural transformation.

C. jejuni transformed (t = 0) with equal amounts of isogenic chromosomal DNA carrying a Strep^R or a Cam^R resistance marker, respectively. At various time points (0–120 min.) following addition of DNA the transformation was terminated by adding DNase I. Single and double transformants were scored by plating on selective agar. Results are representative from three independent experiments. Diamonds, Cam^R transformants, Squares, Strep^R transformants; Triangles, Cam^R Strep^R double transformants.