FIG. 6.

Oxygen metabolism in the presence of NO. A 50-ml suspension of RCV growth medium-malate containing 0.5 mg of R. capsulatus PAS100 per ml was allowed to become anaerobic by its own respiratory activity, in the absence of sparging with nitrogen gas. NO (solid line) and O₂ (dotted line) were monitored simultaneously with electrodes. NO additions (300-nmol aliquots) are marked with arrows. After enough NO had been added so that NO had accumulated, the oxygen also began to accumulate (panel A and continuing into panel B). Panel B shows that once the [NO] had fallen below approximately 25 nmol in the 50-ml cell suspension (i.e., 0.5 μM NO), oxygen was consumed by the cell suspension.