FIG. 9.

Nitrite uptake rates at intervals after the addition of ammonium (2 mM) or chloramphenicol (20 μg · ml⁻¹) to cells grown steadily on ASW_NO3. Nitrite taken up from the medium was monitored for 20 min, and the uptake rate per cell was determined for each datum point. Rates were calculated as a percentage of the initial uptake rate. The initial uptake rate was 0.13 fmol of NO₂ per cell per h.