In vivo expression of walR and walK in B. anthracis at different growth stages – O.D.600nm ∼0.3 (early exponential phase), 0.6 (mid exponential phase), 0.9 (late exponential phase), 1.2 (onset of stationary phase). (A) qRT-PCR for walR and walK transcripts from B. anthracis total RNA. Transcripts for both the genes could be detected at all the tested growth stages. Normalized Ct values are plotted against different growth stages, using GraphPad Prism 5 software. Mean with SEM values, from two independent experiments carried out in triplicate are shown. (B) Immunoblotting for endogenous WalR protein expression in B. anthracis. WalR could be detected in B. anthracis lysates from all the tested growth stages using anti-WalR antisera. A single band could be observed at the same position as recombinant WalR monomer (+). Equal protein was loaded for all the samples as shown in the coomassie stained SDS–PAGE gel. No band could be detected in any of the B. anthracis fractions with anti-WalKc antisera. M – Molecular weight standards in kDa.