Ultra du897

Semisynchronous cocultures of B. bacteriovorus were set as described in the supplemental material, with the exception that HM buffer was supplemented with kanamycin and E. coli TOP10/pFW13 was used as the prey. Five microliters of the culture was taken out at the indicated time point and mounted on an agarose-coated microscopy slide. Differential interference contrast (DIC) and fluorescence images were acquired using a Nikon Ti Eclipse microscope equipped with a Spectra X light source (Lumencor) and an Ixon Ultra DU897 electron-multiplying charge-coupled device camera (Andor). Exposure time for mCherry was 2 s. Images were processed in NIS-Elements v4.51 and saved in TIFF format.

Widefield fluorescent images of unroofed PMs were taken with a Nikon N-STORM microscope with a 100× oil immersion objective and an EMCCD camera (Andor Ixon Ultra DU-897). To cover an area of 1 mm² a montage of 15 × 15 images with an overlap of 15% for stitching was taken. The imaged area was marked with a circle (4 mm in diameter) around the centre of the imaged area using an objective diamond scriber. The immersion oil was carefully removed from the bottom of the glass coverslip and the sample was prepared for EM.