Figure 3.

(A) NiCl₂ titration for Tet^r negative selection marker. Bacterial cells with vectors that either contained the CAP resistance gene (control vector) or both the CAP^r and Tet^r (Tet lox-destination vector) were plated on CAP containing the indicated concentration of NiCl₂. The log units of surviving cells are shown on the y-axis. (B) Sucrose titration for sacB negative selection marker. Bacterial cells with vectors that contained either the SacB lox-destination vector (CAP^r and sacB) or a control vector (CAP^r only) were plated on CAP containing the indicated percentage of sucrose. The log units of surviving cells are shown on the y-axis.