Bacterial Cell Morphometry by Phase Contrast

Phase contrast microscopy was performed using stationary phase cultures. Bacteria were immobilized on LB pads containing 1% agarose. Image acquisition was performed using a Zeiss Axio Imager.Z2 microscope equipped with a Plan-Apochromat 63X phase contrast objective lens and an ORCA-Flash 4.0 LT digital CMOS camera (Hamamatsu), using the Zeiss Zen Blue software. For image processing and analysis the MicrobeJ plugin for Fiji was used (Ducret et al., 2016 (link)). Cell length and width from 570 to 700 cells per strain (three fields of 190–250 cells each) were measured and statistical significance was calculated using a t-test (unpaired).