FIGURE 5: Cobalamin uptake by wild-type Anabaena and mutant strains. (A) Model of the strategy for genomic plasmid insertion to generate AFS-I-btuF and AFS-I-btuD. (B) Genomic DNA isolated from wild-type Anabaena and the indicated mutant strains was used for PCR with gene-specific primers (lane 1), a gene-specific primer and a plasmid-specific 3' (lane 2) or 5' primer (lane 3). The asterisk (*) indicates an unspecific PCR product. (C) Wild-type Anabaena was grown in YBG11 medium, followed by growth in YBG11 medium without cobalt for the indicated time. At these time points the uptake rate of cobalamin was determined as describe in methods. Data are shown as average of at least three independent experiments and standard deviation is shown as error bars. The line represents the least square fit result to equation 2. The dashed lines indicate the minimal and maximal uptake rates determined by this analysis. (D) The indicated Anabaena strains were grown in YBG11 medium, followed by growth in YBG11 medium without cobalt for 14 days. The uptake rate was then determined. Data are shown as average of the results of at least three independent experiments and standard deviation is shown as error bars. Statistical analysis on three independent replicas was performed as described in methods. Letters indicate the ANOVA results (p<0.05).