Cultures were grown to mid-exponential phase and 1 ml of the cells was centrifuged at 14,000 rpm for 1 min. The supernatant was removed and the cells were washed with PBS. To stain for chitin, calcofluor white was added to a final concentration of 1 µg/ml in a final volume of 100 µl. The cells were incubated in the dark for 15 min and were gently vortexted every 3–4 min. Cells were washed with PBS and 2 µl of the cells were deposited on a cover slide. To stain for nuclei, the cells were heat fixed on the slide for 1 min at 75 °C and 0.5 µl of 1 mg/ml DAPI was added. All imaging was performed on a Zeiss Imager M1 upright microscope and AxioCam Mrm with AxioVision 4.7 software. For fluorescence microscopy, an X-cite series 120 light source with ET green fluorescent protein (GFP), 4′,6-diamidino-2-phenylindole (DAPI) hybrid, and ET HQ tetramethylrhodamine isothiocyanate (TRITC)/DsRED filter sets from Chroma Technology (Bellows Falls, VT, USA) was used. Calcofluor white and DAPI were viewed under the DAPI hybrid filter and HA-tagged Cas5 was viewed under the Texas Red filter. To facilitate nuclei counting, 12 Z stacks were taken for each image, where each slice is 0.3 μm.