Mutant strains (nit) of Salmonella typhimurium with a pleiotropic defect in nitrogen metabolism.
We have isolated mutant strains (nit) of Salmonella typhimurium that are defective in nitrogen metabolism. They have a reduced ability to use a variety of compounds including glutamate, proline, arginine, N-acetyl-glucosamine, alanine, and adenosine as sole nitrogen source. In addition, although they grow normally on high concentrations of ammonium chloride (greater than 1 mM) as nitrogen source, they grow substantially more slowly than wild type at low concentrations (less than 1 mM). We postulated that the inability of these strains to utilize low concentrations of ammonium chloride accounts for their poor growth on other nitrogen sources. The specific biochemical lesion in strains with a nit mutation is not known; however, mutant strains have no detectable alteration in the activities of glutamine synthetase, glutamate synthetase, or glutamate dehydrogenase, the enzymes known to be involved in assimilation of ammonia. A nit mutation is suppressed by second-site mutations in the structural gene for glutamine synthetase (glnA) that decrease glutamine synthetase activity.
D000117:Acetylglucosamine / Q000378:metabolism; D000643:Ammonium Chloride / Q000378:metabolism; D002874:Chromosome Mapping; D002876:Chromosomes, Bacterial; D005796:Genes; D005969:Glutamate Dehydrogenase / Q000378:metabolism; D005970:Glutamate Synthase / Q000378:metabolism; D005974:Glutamate-Ammonia Ligase / Q000378:metabolism; D005971:Glutamates / Q000378:metabolism; D009154:Mutation; D009584:Nitrogen / Q000378:metabolism*; D000587:Oxidoreductases Acting on CH-NH Group Donors / Q000378:metabolism; D011392:Proline / Q000378:metabolism; D012486:Salmonella typhimurium / Q000201:enzymology / Q000378:metabolism*
D005971:Glutamates; D000643:Ammonium Chloride; D011392:Proline; D005970:Glutamate Synthase; D005969:Glutamate Dehydrogenase; D000587:Oxidoreductases Acting on CH-NH Group Donors; D005974:Glutamate-Ammonia Ligase; D009584:Nitrogen; D000117:Acetylglucosamine