title: Regulation of nitrogen fixation genes.
mesh_terms: D001483:Base Sequence; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005796:Genes; D005798:Genes, Bacterial; D007711:Klebsiella pneumoniae / Q000235:genetics* / Q000378:metabolism; D009586:Nitrogen Fixation; D009876:Operon; D012231:Rhizobium / Q000235:genetics* / Q000378:metabolism