Fluorescence Microscopy

E. coli BL21(DE3) cells possessing the rbcL-egfp-rbcS-pTTQ18 and ccmK4-pTTQ18 plasmids with or without pLFbC901 were cultured in 37°C until OD₆₀₀ reaches 0.6 and then induced with 50 μM IPTG overnight at 18°C. Preparation of E. coli and Syn7942 cells for confocal microscopy was performed as described earlier (Liu et al., 2012). The E. coli and Syn7942 cells were imaged using a Zeiss LSM710 or LSM780 with a 63× or 100× oil-immersion objective and excitation at 488 nm. Live-cell images were recorded from at least five different cultures. All images were captured with all pixels below saturation. Image analysis was carried out using ImageJ software (NIH Image). Automated analysis of the number of carboxysomes in Syn7942 cells was programmed into the image analysis software ImageSXM¹, as described earlier (Sun et al., 2016).