Construction of GFP-Encoding E. coli.

The electrocompetent E. coli cells (BL21[DE3]) were transformed with the pOSIP-CT (TetR, P21) integration plasmid coding for superfolder GFP (sfGFP) (SI Appendix, Supplementary Data 4). The transformed cells were grown at 37 °C for 1 h in LB media and then for 12 h in LB media supplemented with tetracycline (50 μg/mL). Then, the GFP-positive cells were sorted by using a BD FACS Aria III Cell Sorter (BD Biosciences). The sorted cells were plated on a 100-mm LB-agar petri dish and grown at 37 °C for 16 h. Next, individual cell colonies were regrown in LB media at 37 °C, collected at approximately OD₆₀₀ = 1, and stored at −80 °C in LB media supplemented with 50% glycerol.