IDENTIFICATION OF THE NIFJ GENE CODING FOR PYRUVATE-FERREDOXIN OXIDOREDUCTASE IN DINITROGEN-FIXING CYANOBACTERIA

A 329 bp DNA segment from both Anabaena variabilis and Anabaena PCC 71 19 was amplified using the polymerase chain reaction (PCR). The sequen ces from the two cyanobacteria showed strong similarities to the corre sponding part of the nifJ gene from Klebsiella pneumoniae and Enteroba cter agglomerans. The present findings underline earlier results of en zymatic studies that heterocystous cyanobacteria possess a pyruvate: f erredoxin (flavodoxin) oxidoreductase (PFO). The nifJ gene segment cou ld not be detected in the non-dinitrogen-fixing, unicellular cyanobact erium Anacystis nidulans which is also in accord with previous finding s from enzyme assays.