3D-UHU grown on filter membranes were Immunostained then mounted with ProLong Glass antifade mountant (Invitrogen) and imaged on a Leica SP8 microscope. Images were acquired using 63x magnification with 0.3 µm Z step size giving 50% image overlap required for 3D image reconstruction. Images were processed using LAS X software version 3.5.7.