[57]. This is the first genome-wide study on the regulatory role of ArcA in S. Typhimurium (14028s) under anaerobic conditions. ArcA was found to directly or indirectly control the

expression of at least 392 genes. In particular, we showed that ArcA is involved in energy metabolism, flagella biosynthesis, and motility. Additionally, the arcA mutant was as virulent as the WT, although it was non-motile. Furthermore, prior to the present report, none of the virulence genes (i. e., SPI-3 and Gifsy-1) had been identified as part of the www.selleckchem.com/products/ipi-145-ink1197.html Salmonella ArcA regulon. Finally, several genes involved in metabolism previously identified as being regulated by ArcA in E. coli [5–17, 49–52] were also identified in the present study selleck kinase inhibitor (Additional file 1: Table S1). Logo comparison In a recent study, a logo was used to graphically compare multiple ArcA sequence alignments of Shewanella oneidensis [58] to that of E. coli [12]. The analysis revealed subtle changes in base pairs at each position between the sequences. Although the ArcA binding motifs of S. oneidensis and E. coli were similar, the arcA regulons and the physiological function of ArcA in these two organisms were different [58]. When comparing the ArcA logos of E. coli and S. oneidensis to the one generated herein for S. Typhimurium, we found that

there is similarity between S. Typhimurium and both E. coli and S. oneidensis. However, while there is very little variation between the nucleotide sequences at each base pair of S. Typhimurium and E. coli, there Glutathione peroxidase is much more variation between S. Typhimurium and S. oneidensis. Therefore, when comparing the genes regulated by ArcA in these three organisms, it is evident that the ArcA regulons of E. coli and S. Typhimurium

are more similar than that of S. oneidensis. ArcA and carbon metabolism Comparing our microarray data in S. Typhimurium to the published data of E. coli [5, 12], there are several aspects pertaining to metabolic regulation that are similar between these two organisms. Anaerobically, several ArcA-repressed genes identified in our microarray data are involved in metabolism and transport, while ArcA-activated genes included those coding for enzymes involved in glycogen synthesis and catabolism as well as those for gluconeogenesis. Expression of many of these genes was consistent with those reported in E. coli [5, 9, 11–14, 52], H. influenzae [59], and S. oneidensis [60]. The genes of the two-component tricarboxylic transport system (tctE, STM2786, STM2787, STM2788, and STM2789) were the most highly repressed by ArcA (Additional file 1: Table S1). This was not surprising since transport systems for substrates of aerobic pathways have been suggested to be candidates for regulation by ArcA [14]. A similar pattern of anaerobic regulation of these enzymes has also been seen in our previous global analysis of Fnr [20] (Additional file 1: Table S2). In E.