@article{evans_fink_vazquez-torres_porwollik_jones-carson_mcclelland_hassan_2011, title={Analysis of the ArcA regulon in anaerobically grown Salmonella enterica sv. Typhimurium}, volume={11}, ISSN={["1471-2180"]}, DOI={10.1186/1471-2180-11-58}, abstractNote={Salmonella enterica serovar Typhimurium (S. Typhimurium) is a Gram-negative pathogen that must successfully adapt to the broad fluctuations in the concentration of dissolved dioxygen encountered in the host. In Escherichia coli, ArcA (Aerobic Respiratory Control) helps the cells to sense and respond to the presence of dioxygen. The global role of ArcA in E. coli is well characterized; however, little is known about its role in anaerobically grown S. Typhimurium.We compared the transcriptional profiles of the virulent wild-type (WT) strain (ATCC 14028s) and its isogenic arcA mutant grown under anaerobic conditions. We found that ArcA directly or indirectly regulates 392 genes (8.5% of the genome); of these, 138 genes are poorly characterized. Regulation by ArcA in S. Typhimurium is similar, but distinct from that in E. coli. Thus, genes/operons involved in core metabolic pathways (e.g., succinyl-CoA, fatty acid degradation, cytochrome oxidase complexes, flagellar biosynthesis, motility, and chemotaxis) were regulated similarly in the two organisms. However, genes/operons present in both organisms, but regulated differently by ArcA in S. Typhimurium included those coding for ethanolamine utilization, lactate transport and metabolism, and succinate dehydrogenases. Salmonella-specific genes/operons regulated by ArcA included those required for propanediol utilization, flagellar genes (mcpAC, cheV), Gifsy-1 prophage genes, and three SPI-3 genes (mgtBC, slsA, STM3784). In agreement with our microarray data, the arcA mutant was non-motile, lacked flagella, and was as virulent in mice as the WT. Additionally, we identified a set of 120 genes whose regulation was shared with the anaerobic redox regulator, Fnr.We have identified the ArcA regulon in anaerobically grown S. Typhimurium. Our results demonstrated that in S. Typhimurium, ArcA serves as a transcriptional regulator coordinating cellular metabolism, flagella biosynthesis, and motility. Furthermore, ArcA and Fnr share in the regulation of 120 S. Typhimurium genes.}, journal={BMC MICROBIOLOGY}, author={Evans, Matthew R. and Fink, Ryan C. and Vazquez-Torres, Andres and Porwollik, Steffen and Jones-Carson, Jessica and McClelland, Michael and Hassan, Hosni M.}, year={2011}, month={Mar} }
 @article{heluane_evans_dagher_bruno-barcena_2011, title={Meta-Analysis and Functional Validation of Nutritional Requirements of Solventogenic Clostridia Growing under Butanol Stress Conditions and Coutilization of D-Glucose and D-Xylose}, volume={77}, ISSN={["1098-5336"]}, url={http://europepmc.org/abstract/med/21602379}, DOI={10.1128/aem.00116-11}, abstractNote={ABSTRACT Recent advances in systems biology, omics, and computational studies allow us to carry out data mining for improving biofuel production bioprocesses. Of particular interest are bioprocesses that center on microbial capabilities to biotransform both the hexose and pentose fractions present in crop residues. This called for a systematic exploration of the components of the media to obtain higher-density cultures and more-productive fermentation operations than are currently found. By using a meta-analysis approach of the transcriptional responses to butanol stress, we identified the nutritional requirements of solvent-tolerant strain Clostridium beijerinckii SA-1 (ATCC 35702). The nutritional requirements identified were later validated using the chemostat pulse-and-shift technique. C. beijerinckii SA-1 was cultivated in a two-stage single-feed-stream continuous production system to test the proposed validated medium formulation, and the coutilization of d-glucose and d-xylose was evaluated by taking advantage of the well-known ability of solventogenic clostridia to utilize a large variety of carbon sources such as mono-, oligo-, and polysaccharides containing pentose and hexose sugars. Our results indicated that C. beijerinckii SA-1 was able to coferment hexose/pentose sugar mixtures in the absence of a glucose repression effect. In addition, our analysis suggests that the solvent and acid resistance mechanisms found in this strain are differentially regulated compared to strain NRRL B-527 and are outlined as the basis of the analysis toward optimizing butanol production.}, number={13}, journal={APPLIED AND ENVIRONMENTAL MICROBIOLOGY}, author={Heluane, Humberto and Evans, Matthew R. and Dagher, Sue F. and Bruno-Barcena, Jose M.}, year={2011}, month={Jul}, pages={4473–4485} }
 @article{fink_evans_porwollik_vazquez-torres_jones-carson_troxell_libby_mcclelland_hassan_2007, title={FNR is a global regulator of virulence and anaerobic metabolism in Salmonella enterica serovar typhimurium (ATCC 14028s)}, volume={189}, ISSN={["1098-5530"]}, DOI={10.1128/JB.00726-06}, abstractNote={ABSTRACT}, number={6}, journal={JOURNAL OF BACTERIOLOGY}, author={Fink, Ryan C. and Evans, Matthew R. and Porwollik, Steffen and Vazquez-Torres, Andres and Jones-Carson, Jessica and Troxell, Bryan and Libby, Stephen J. and McClelland, Michael and Hassan, Hosni M.}, year={2007}, month={Mar}, pages={2262–2273} }