Figure 4. Purified, transformed RBs have β – lactamase activity.

In Panel A equal amounts of purified RBs (measured by qPCR of the genome) from transformed C. trachomatis L2/434/Bu and the wild–type parental C. trachomatis L2/434/Bu were assayed for β – lactamase activity. In Panel B equal amounts of E. coli and E. coli transformed with pBR325::L2 were used as controls to verify the assay. Hydrolysis of Nitrocefin is measured in pH 7.0 buffer by absorbance at 486 nm over 60 min. Nitrocefin is a chromogenic β – lactamase substrate.