Evaluation of strength of sodC promoters from B. abortus, B. neotomae, B. suis biovars 2 (strain Thomsen) and 4 (strain 40).
A) Nucleotide sequence features of the promoter-containing 5′ flanking region of B. abortus sodC gene as cloned in pBaSODpro/lacZ. The sodC start codon, ribosomal binding site (RBS), and 5′ ends of cDNA are indicated in bold. The asterisk indicates the site of nucleotide insertion polymorphism with B. neotoame and B. suis biovars. The two potential −10 sequences are boxed (see Discussion). B) Expression levels of β-galactosidase in late log phase cultures of B. neotomae cultures harboring plasmids with lacZ gene cloned under the control of sodC promoters obtained from the indicated Brucella spp. For each promoter construct, the assays were performed using 3 separate colony cultures. Results are shown as the mean ± standard deviation of Miller units. Means with the same number of asterisks were not significantly different from each other (P>0.05). There were significant differences between means with different number of asterisks (P<0.001).