Skip to main content
. 2022 Mar 18;78:103943. doi: 10.1016/j.ebiom.2022.103943

Figure 6.

Fig 6

Plumbagin inhibited the transcription and expression of resistance genes tet(X3)/tet(X4). (a) Plumbagin suppressed the DNA synthesis of tet(X3)/tet(X4) in E. coli. The tet(X3)/tet(X4) gene in E. coli treated with the indicated concentrations of plumbagin was amplified by PCR analysis, and then the desired products were determined using DNA gel electrophoresis. And 16s rRNA was used as an internal control. (b) The expression of Tet(X4) in E. coli BL21-pGEX-4T-1-Tet(X4) was decreased by plumbagin with boiling. (c) Plumbagin addition decreased the expression of Tet(X3)/Tet(X4) in E. coli BL21-pGEX-4T-1-Tet(X3) or E. coli BL21-pGEX-4T-1-Tet(X4) induced by IPTG. Samples were loaded on SDS-PAGE gels and analysed by staining with Coomassie brilliant blue. (d) Tet(X4) production in E. coli J53p47EC with tet(X4) and E. coli J53 without tet(X4) following coculture with the indicated concentrations of plumbagin (0, 8 and 32 μg/mL) was determined by western blotting assays. (e) Tet(X3)/Tet(X4) production in tet(X3)/tet(X4)-positive engineering strains and clinical strains cocultured with the indicated treatment were determined by western blotting assays. (f) Dose-dependent inhibition of the transcription of the genes tet(X3)/tet(X4)-encoding monooxygenases by plumbagin was determined by RT-PCR analysis. *p < 0.05, **p < 0.01 (Student's t test). All data are representative of three independent experiments and are presented as the mean ± SD.