Figure 1. Phenotypic characterization of kpnO mutant.

A) The kpnO mutant (ΔkpnO) had different colony morphology with smaller (0.75±0.05 mm on average) and less regular colonies than the wild-type (WT) (3.0±0.5 mm on average). B) The hypermucoviscosity string test was performed by measuring the formation of a viscous string stretched between the bacterial colony and the inoculation loop. The average lengths of WT, ΔkpnO were (5.0±0.5 cm) and (0.51±0.02 cm) respectively. C) The precipitation test was carried out on 12 h grown strains in LB broth at 37°C, and each pellet was evaluated after centrifugation at 4000rpm for 3 min. The WT and ΔkpnO showed profound difference in the compactness of the pellet. D) Cells were grown to late log phase in shaking culture and stained with crystal violet followed by treatment with 20% copper sulphate solution. The WT and ΔkpnO were visualized in Olympus microscope work station.