RNase activity measurements using FRET-based RNA probe.

The droplets containing FRET-based RNA probe (A) with and (B) without commercial RNase A were observed using fluorescence microscopy. (C) Histograms obtained from On-chip Sort analysis describe the distributions of the fluorescence intensities of the droplets containing FRET-based RNA probe with (blue line) and without (red line) commercial RNase A. (D) Averages of fluorescence intensity of approximately 1,000 droplets analyzed by On-chip Sort. Blue circles, droplets containing LB medium. Red circles, droplets containing LB medium, FRET-based RNA probe, and RNase A. Orange circles, droplets containing crude supernatant of E. coli cultivated for 1 day and FRET-based RNA probe. Green circles, droplets containing crude supernatant of B. subtilis cultivated for 1 day and FRET-based RNA probe. Pink circles, droplets containing crude supernatant of S. aureofaciens cultivated for 2 days and FRET-based RNA probe. Purple circles, droplets containing crude supernatant of S. aureofaciens cultivated for 4 days and FRET-based RNA probe. (E) Averages of fluorescence intensity of approximately 1,000 droplets analyzed by On-chip Sort. Blue circles, droplets containing NBRC805 medium. Red circles, droplets containing NBRC805 medium, FRET-based RNA probe, and RNase A. Black circles, droplets containing crude supernatant of B. japonicum cultivated for 6 days and FRET-based RNA probe.