Interestingly, most of the 120 genes were regulated by ArcA and Fnr in the same fashion (i.e., repressed or activated) except for yneB (putative fructose-1,6-bisphosphate aldolase – STM4078), which was activated by ArcA, but repressed by

Fnr (Additional file 1: Table S2). The opposing regulation CDK inhibitor of yneB by ArcA and Fnr indeed warrant further studies. Conclusion(s) Herein, we report on the role of the two-component regulator, ArcA, in the genome-wide response to oxygen in Salmonella. Our data clearly demonstrate that ArcA serves, directly or indirectly, as a regulator/SN-38 chemical structure modulator of genes involved in aerobic/anaerobic energy metabolism and motility. In a recent study [20], we demonstrated that the oxygen sensing, selleck chemical global regulator, Fnr participates in coordinating anaerobic metabolism, flagellar biosynthesis, motility, chemotaxis, and virulence in S. Typhimurium. In the present study, we identified a set of 120 genes whose regulation is shared between ArcA and Fnr. We also demonstrated that Fnr plays a more hierarchical role than ArcA in pathogenesis. Furthermore, under our experimental conditions, we demonstrated that the lack of

motility does not necessarily correspond to the lack of virulence in S. Typhimurium. Acknowledgements This work was supported in part by the North Carolina Agricultural Research Services (to HMH), and by NIH grants R01AI034829, R01AI022933, R21AI057733, and R01AI52237 and generous gifts from Mr. Sidney Kimmel and Mr. Ira Lechner (MM and SP), NIH grants AI054959 and RR16082 (AV-T and JJ-C). We appreciate the donation of the anti-ArcA antibodies from Dr. Philip Silverman and Ms. Robin Harris at the Department of Botany and Microbiology, University of Oklahoma. We would Etomidate also like to thank Valerie Knowlton for her assistance with the microscopy. We are grateful to Drs. Gabriele Gusmini and Russell Wolfinger

for their assistance with the statistical analyses/SAS software. Electronic supplementary material Additional file 1: Analysis of the ArcA regulon in anaerobically grown Salmonella enterica sv . Typhimurium. Identification of ArcA by Western blot; Effects of H2O2 on viability of the ArcA mutant; List of genes differentially regulated by ArcA; and List of genes shared with the Fnr regulon. A. Supplemental Methods: Western blot analysis of ArcA. H2O2 survival assays. B. Supplemental Figures: Figure S1. Western blot of total proteins of the WT, arcA mutant, and arcA -/parcA complement strains. Figure S2. Effects of hydrogen peroxide on viability of the WT and the arcA mutant under anerobiosis. C. Supplemental Tables: Table S1.