Uplanfl 100

Time-lapse videos were used to observe the colony margins, as previously reported (Sato et al., 2021b (link)). The plate was inverted on the sample stage and observed from underneath using an All-in-One Fluorescence Microscope BZ-X800 (KEYENCE). Images were visualized with a phase contrast objective LUCPlanFLN 20× (Olympus). The phase contrast microscope images were taken every 30 s. The images were analyzed, adjusted, and cropped using a BZ-X800 analyzer software (KEYENCE).
Time-lapse videos were made around the colony spreading of GFP-expressing F. johnsoniae strains using a BX50F microscope (Olympus). The culture plate was placed on a sample stage, and a cover glass was carefully placed over the colony. After the top surface of the dendrites formed was imaged using phase contrast microscopy, fluorescence signals in the same area were observed to track the cells using confocal laser scanning fluorescent microscopy (CLSM) with an objective lens of UPlanFl 100× (Olympus) and ANDOR iXon EMCCD camera (Oxford Instruments, Abingdon, UK) in combination with Andor iQ3 software (Oxford Instruments). Exposure time of each image was typically 100 ms (excitation light: 490–510 nm, emission light: 520–550 nm). Fluorescence images were taken every 3 s for 10 min, and movies were produced.

For microscopic observations, an Olympus System microscope Model BX51 (Olympus) equipped with UPlanSApo 60× and UPlanFL 100× objective lenses (Olympus, Shinkjuku, Japan) and a stereomicroscope Model SMZ800 (Nikon, Minato, Japan) were used. Images were captured with a DP71 digital camera (Olympus) and processed using DP manager imaging software (Olympus, Shinkjuku, Japan).