Figure 1
The S. mutans alr mutant was constructed using homologous recombination. (a) Two 500 bp fragments were generated (p1p2: up-stream, and p3p4: down-stream of alr) using the primer pair alr-up-f/ldh and alr-down-f/ldh. An erm fragment (876 bp) was amplified using the primer pair ldh-f/erm-r. (b) The three digested fragments ligated using T4 DNA ligase to generate the proposed segment. (c) This fragment was transformed into S. mutans, and the transformants were selected on BHI broth plates containing 12.5 μg·mL−1 of erythromycin. Δalr, S. mutans alr mutant; BHI, brain heart infusion.
