Fig. 2

The characteristics of Δfis. A Colony morphology of PmCQ2, Δfis, C-fis and O-fis cultured on Martin agar plates. B Growth curves of strains cultured in Martin broth and LB media at 37 °C with shaking at 200 rpm (The experiment was performed in triplicate). C Capsular polysaccharide production. D Quantification of biofilm production. E Heme binds iron uptake. F The transcription of haemoglobin receptors in PmCQ2 and Δfis, respectively. All data are expressed as mean ± SD. * P < 0.05; ** P < 0.01; *** P < 0.001; ns means no significant