Nitrite uptake and its regulation in the cyanobacterium Anacystis nidulans

Two different components seem to participate in the uptake of nitrite by the cyanobacterium Anacystis nidulans, namely a transport system sensitive to N,N′-dicyclohexylcarbodiimide and a passive influx. The relative contribution of each component depended on the pH of the medium, that of the active system being prevalent at high pH values. The active transport of nitrite appears to be mediated by a high-affinity system, whereas the affinity for nitrite of the passive system is lower, similar to that of nitrite reductase. The utilization of nitrite was inhibited by products of the assimilation of ammonium via glutamine synthetase, apparently acting at the level of the active component involved in nitrite uptake.