FIG 5.

Reporter enzyme fluorescence probes behave similarly in buffer and sputum containing transport stabilization solution (TSS). Correlation of activity (change in fluorescence per minute, excitation, 490 nm; emission, 515 nm) from 1 μM CDG-3 incubated with different concentrations of BlaC in sputum containing TSS (A) and MES buffer, pH 6.0, (B) for 40 min at room temperature (25°C). Linear correlation value (R²) is shown on both graphs. (C) Change in fluorescence for 1 μM CDG-3 in the presence of 0.2 nM BlaC in sputum over time at room temperature (25°C). Change in fluorescence (ΔF) is calculated as the fluorescent signal at each time point minus the signal immediately after adding the substrate. All experiments were carried out in duplicate, and the averages and standard deviations reported. (D) Fluorescence emission spectrum of CDG-3 before and after treatment with 0.2 nM BlaC for 40 min in sputum at room temperature (25°C) with excitation at 490 nm.