Oxygen-dependent regulation of the respiration and growth of Escherichia coli by nitric oxide

To elucidate the role of nitric oxide (NO) in the metabolisms of enteric bacteria, its effect on the respiration and growth of Escherichia coli was examined. Respiration of E. coli was reversibly inhibited by NO particularly under low oxygen tensions. Growth of E. coli was also inhibited by NO more strongly under low oxygen tension than at its high concentration. Because the intestinal lumen is anaerobic, even a small amount of NO might strongly inhibit the energy metabolism and growth of E. coli and other enteric bacteria in vivo than in air atmospheric conditions in which oxygen tension is unphysiologically high.