Fig 2

Expression of BgaB in E. coli OmniMax and B. subtilis 1012 on X-gal plates and in liquid medium. a, Bacterial cells containing pHT01 (Pgrac, negative control), pHT01-bgaB (Pgrac01-bgaB), pHT100 (Pgrac100-bgaB) and pHT212 (Pgrac212-bgaB) were spotted on X-gal LB agar plates containing appropriate antibiotics and 0.01 mM IPTG for B. subtilis and without IPTG for E. coli at 30 °C for 48 h. Then, pictures were taken and single colonies are shown. b, The bacterial cells were grown in liquid LB medium at 37 °C to the mid-logarithmic growth phase, and then induced with 0.01 mM IPTG for B. subtilis and kept un-induced for E. coli. The cells were collected after 4 h of induction, and the BgaB activities were measured. The ratio of β-galactosidase activities of the samples were calculated from induced B. subtilis cells and un-induced E. coli cells. The ratio was set as one when the BgaB activities from both E. coli and B. subtilis were identical [4, 5]. c, E. coli cells containing pHT01 (Pgrac, negative control), pHT100 (Pgrac100-bgaB), pHCMC04-bgaB (PxylA-bgaB), pHCMC05-bgaB, pHT01-bgaB (Pgrac01-bgaB were spotted on X-gal LB agar plates containing ampicillin. d, the E. coli cells were grown in liquid LB medium at 37 °C to the mid-logarithmic growth phase, then the growing cells collected and the BgaB activities were measured. The ratio of β-galactosidase activities of the samples were calculated from different constructs to Pgrac01-bgaB