FNR- vs WT in anoxic conditions

Salmonella enterica var. Typhimurium (S. Typhimurium) is a Gram-negative, facultative intracellular pathogen that infects the intestinal tracts of humans and animals. In the host, S. Typhimurium encounters a wide range of oxygen concentrations going from oxic conditions in the stomach to near anoxic conditions in the distal sigmoid colon-rectal junction. In Escherichia coli, FNR (Fumarate Nitrate Reductase) is one of the main regulatory proteins involved in oxygen sensing and in controlling the transcription of the genes required for the aerobic/anaerobic transition.. However, the role of FNR in S. Typhimurium is largely unknown. To assess its role in S. Typhimurium, we constructed an FNR- mutant (NC983) in the pathogenic wild-type (WT) strain, ATCC14028s. Keywords: FNR, Salmonella, anaerobic, virulence The WT and the fnr- mutant strains were grown under anaerobic conditions in a Coy Anaerobic Chamber. Total RNAs were isolated when the cultures reached an OD600 of 0.3 (mid-log). Microarray slides were used to compare the global expression patterns of the two strains (i.e., 14028s vs. NC983). On each slides there were three replicas of the Salmonella genome and we swapped dyes, thus having a total of six replicates for each gene.