Figure 3

The NifA activity is higher in H. seropedicae strains lacking both Fnr1 and Fnr3. The RNA from the strains MBN1 (nifA deletion), MBN2 (nifA deletion in the double fnr1, fnr3 deletion background) and MBN3 (nifA deletion in the triple fnr deletion background) complemented with the plasmid pRAMM1 (expressing H. seropedicae NifA from lac promoter) was purified and submitted to direct RT-PCR amplification of nifH gene as described in Methods. The 16S rRNA (rrsA) was used as an endogenous expression control. A representative gel from two independent RNA extractions is showed.