title: Ammonia-excreting mutants of Klebsiella pneumoniae with a pleiotropic defect in nitrogen metabolism.
abstract: Enterobacterial mutants defective in the nitrogen control regulatory system (Ntr) generally display a pleiotropic phenotype with regard to expression and regulation of several enzymes and transport systems involved in the assimilation of N sources. This report describes the isolation and characterization of similar pleiotropic mutants of Klebsiella pneumoniae that cannot be complemented by ntr genes. The strains excreted ammonia, were unable to grow on a number of N sources, and contained low glutamine:2-oxoglutarate amino transferase and normal, but unmodifiable glutamine synthetase activities and a nitrogenase level largely unaffected by ammonium, but still repressible by an amino acid mixture. Genetic studies suggested that this phenotype is due to overexpression of an unknown regulatory protein.
authors.affiliation: Lehrstuhl Mikrobiologie, Universität Bayreuth, D-95470, Bayreuth, Germany.
authors.forename: T
authors.initials: T
authors.lastname: Kuczius
authors.forename: D
authors.initials: D
authors.lastname: Kleiner
mesh_terms: D000596:Amino Acids / Q000378:metabolism; D000641:Ammonia / Q000378:metabolism*; D015153:Blotting, Western; D004591:Electrophoresis, Polyacrylamide Gel; D015964:Gene Expression Regulation, Bacterial; D015971:Gene Expression Regulation, Enzymologic; D015723:Gene Library; D005974:Glutamate-Ammonia Ligase / Q000378:metabolism; D005973:Glutamine / Q000378:metabolism; D007711:Klebsiella pneumoniae / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism*; D016296:Mutagenesis; D009584:Nitrogen / Q000378:metabolism*; D009591:Nitrogenase / Q000378:metabolism; D010957:Plasmids; D000637:Transaminases / Q000378:metabolism
chemical_list: D000596:Amino Acids; D005973:Glutamine; D000641:Ammonia; D009591:Nitrogenase; D000637:Transaminases; C020656:glutamine-pyruvate aminotransferase; D005974:Glutamate-Ammonia Ligase; D009584:Nitrogen