Fig. 5.
Effect of LptD depletion in GC. A, Construction of an lptD conditional knockout in GC strain FA1090 was achieved by allelic replacement of the native lptD promoter with a DNA fragment containing IPTG-inducible promoter (Plac), lacI gene, and a nonpolar antibiotic resistance cassette apha3 (kanR). B, FA1090 cells carrying chromosomal PlaclptD were grown in the presence of 100 μm IPTG on GCB agar plates for 18 h. The bacteria were collected from plates, washed, divided, and growth was continued in the presence or absence of IPTG as indicated. Cell viability was monitored every hour by spotting serial dilutions onto GCB agar plates with (+) or without (-) IPTG, as indicated. Experiments were performed in biological quadruplicates and means and S.E. of colony forming units calculated per ml of bacterial cultures (CFU/ml) are presented. C, Representative experiments showing CFU's of strains spotted after 5 h onto GCB agar plates with or without IPTG. D, Representative micrographs illustrating the colony morphology of FA1090 PlaclptD expressing LptD (+ IPTG) and upon depletion of LptD (− IPTG). GC colonies were visualized with a Zeiss AxioObserver.D1 microscope at A-Plan 10× magnification 0.25 Phase Contrast 1.