Discovery and dissection of metabolic oscillations in the microaerobic nitric oxide response network of Escherichia coli

Significance Many bacteria use NO· dioxygenase and NO· reductase to defend themselves against immune-generated NO·. The importance and contribution of these systems under microaerobic conditions, which pathogens are likely to encounter within a host, remain poorly understood. We investigated the NO· response of Escherichia coli throughout the microaerobic regime, and discovered conditions that largely disabled the NO· defenses of E. coli , and environments where the [NO·] oscillated. Components found to comprise the oscillatory circuit are distributed broadly among bacterial species, suggesting that these dynamics could be a characteristic feature of how bacteria respond to NO· in low O 2 environments. In support of this hypothesis, analogous oscillations were observed in NO·-stressed cultures of Pseudomonas aeruginosa under low O 2 conditions.