Figure 2.

Plasmid stability. GFP expression was induced with 500 ng/ml of ATc. ON culture of day 0 was supplemented with 15 μg/ml kanamycin, while ON cultures of days 1–4 were supplemented with 50 μg/ml ampicillin. (A) GFP expression in F. novicida U112 pFNMB1 msfgfp ON cultures of day 0 and day 4. (B) GFP expression in F. novicida U112 pFNMB2 msfgfp ON cultures of day 0 and day 4. (A,B) Images are a merge of phase contrast and GFP channel. 26 × 39 μm fields of view are shown. Scale bar represent 5 μm. Representative replicates are shown. Three independent experiments were performed. (C) Survival assay performed with ON cultures of F. novicida U112 pFNMB1 msfgfp and F. novicida U112 pFNMB2 msfgfp plated on ampicillin and ampicillin/kanamycin plates. Three independent experiments were performed. (D) Digestion of pFNMB1 msfgfp with SacI and SpeI restriction enzymes. (E) Digestion of pFNMB2 msfgfp with SacI and SpeI restriction enzymes. (D,E) Plasmids were passaged in F. novicida for 4 days before being transformed into E. coli. Controls were isolated directly from E. coli. Representative replicates are shown. Three independent experiments were performed.