Phase and fluorescence time-lapse imaging was performed on a Nikon Ti-E inverted microscope, equipped with a Plan Apo 60×, 1.40 NA, Oil, Ph3 DM objective and 1.5× magnifier. Images were acquired every 5 min, and fluorescent proteins were illuminated with a Lumencor Spectra × light engine equipped with excitation filters 470/24 (GFP), 510/25 (YFP) or 575/25 (mCherry), Chroma emission filters 510/40 (GFP), 545/30 (YFP), 530/60 (mCherry) and either a quad polychroic DAPI/FITC/Cy3/Cy5 or triple polychroic CFP/YFP/mCherry cube for Lumencor SpectraX. Images were acquired using an Andor iXon3 DU885 EM CCD camera driven by NIS Elements Advanced Research software (Nikon, Melville, NY)
Cultures from strain YB4667 CB15::pvan-ftsZ-yfp were grown in PYE medium at 30°C and induced for 2 hours with 0.5 mM vanillic acid to express FtsZ-YFP. Exponentially growing cells from this culture were spotted onto a 0.8 mm thick 1% agarose pad made with PYE medium containing 0.5 mM vanillic acid and timelapse images were acquired every 5 minutes from 16 different slide positions for 54 time points. For cell division inhibition, 30 µg/ml of cephalexin was added to the agarose pad during the imaging period.
For precision assessment of MicrobeJ, Molecular Probes FluoSpheres carboxylate-modified microspheres (F8823), 1± 0.0480 µm lot #1761288 were spotted onto a 1% agarose pad made with deionized water and images were acquired for 30 ms using the same microscope, camera and objective as cells.