Fig. 3:

Under Wide Field Illumination, PSCFP2 is Photostable. A. fluorescent proteins, without fused sequences, were continuously irradiated for 300 seconds with appropriate filter sets, with images captured every two seconds in live NIH 3T3 cells. Monochrome images were quantified using Image J (NIH), normalized to start fluorescent levels, and plotted over time. Deviations across three experiments for each fluorophore was <5%. B. PSCFP2 does not photoactivate with 175W unfiltered xenon light over 15 minutes constant irradiation. Light was provided without filtration through a liquid light guide and using a plan apochromat NA1.3 63X oil immersion objective (Nikon). While slight photobleaching was noted, (panels a versus c), no cyan fluorescence was detected above CCD camera noise (panels b,d). Scale bar is 10 μm.