Fig. 4.
Effect of disruption of F. johnsoniae sprT on gliding motility, surface localization of SprB protein, and extracellular chitinase activity. (A) Colony morphology of wild-type, mutant, and complemented strains. Cells were incubated on PY2 agar at 25 °C for 45 h. (Scale bar: 0.5 mm.) (B) Detection of surface localized SprB protein by immunofluorescence microscopy. Cells of wild-type and mutant F. johnsoniae were exposed to DAPI and to anti-SprB antibodies followed by secondary antibodies conjugated to Alexa 488. Arrows indicate InSpeck relative-intensity fluorescence beads. (Scale bar: 10 μm.) (C) Chitinase activities of intact cells and culture supernatants of F. johnsoniae strains with three synthetic substrates for chitinase, 4-MU-GlcNAc, 4-MU-(GlcNAc)2, and 4-MU-(GlcNAc)3.