Fig. 1From: Acceleration of emergence of E. coli antibiotic resistance in a simulated sublethal concentration of copper and tetracycline co-contaminated environmentDiagram exposure sub-culture and schematic experimental design. Antibiotic resistance selection by both copper ion (Cu (II)) and tetracycline (Tet). The initial bacterial culture with copper ions and tetracycline treatments or without any copper ions or tetracycline treatment (control groups) as cycle 0 (recorded as C0), and subsequent were recorded as C1, C2, etc. Each cycle was 8 days, a total of 5 cycles. a Cycles of the exposure sub-culture; b The concentrations of Cu (II) and Tet, during 5 cycles of sub-cultures for antibiotic resistance selection with mental ions of Cu (II) and Tet. The concentration of tetracycline during the experiments was set as 0.0234 mg/L, gradually increasing the copper ion dose concentrations from 1/100 × MIC (20 mg/L) up to 1/10 × MIC (100 mg/L), as the relatively high concentration evolution condition; and relatively lower concentrations of copper ion at about 10 mg/L. H: Strains exposure at high copper ion concentrations; L: Strains exposure at low copper ion concentrations. All experiments were performed in triplicateBack to article page