Similar effects of an NO challenge and an lpdA knockout on transcription of Salmonella enterica sv Typhimurium 14028

Transcriptional profiling of Salmonella enterica sv Typhimurium under NO stress and comparison of profiles between wild type and lpdA mutant cultures. We investigated the bacteriostatic nature of NO·. S. Typhmurium 14028s is prototrophic for all amino acids but cannot synthesize Methionine or Lysine during nitrosative stress. This MK auxotrophy results from reduced availability of succinyl-CoA, a consequence of NO· targeting lipoamide-dependent LpdA activity. LpdA is an essential component of the pyruvate and α-ketoglutarate dehydrogenase complexes. Additional effects of NO· on gene regulation prevent compensatory pathways of succinyl-CoA production. By microarray analysis, more than 50% of the transcriptional response of S. Typhimurium to nitrosative stress is attributable to LpdA inhibition. Two separate two-condition experiment: NO treated versus untreated, wild type versus lpdA mutant. Three biological replicates. Dye swaps performed on two of these.