title: Nitrogen source influences natural abundance (15)N of Escherichia coli.
abstract: Escherichia coli cells were forced to mineralize or assimilate nitrogen in vitro by manipulating substrate carbon and nitrogen availability. When grown on an organic nitrogen source, E. coli cells released NH(4)(+) and were enriched in (15)N relative to the nitrogen source (1.6-3.1 per thousand). However, when cells were grown on an inorganic nitrogen source, the biomass was depleted (6.1-9.1 per thousand) relative to the source. By measuring (15)N enrichment of microorganisms relative to nitrogen pools, ecosystem ecologists may be able to determine if microorganisms are assimilating or mineralizing nitrogen.
authors.affiliation: Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA. Jessica.Collins@nau.edu
authors.forename: Jessica G
authors.initials: JG
authors.lastname: Collins
authors.forename: Paul
authors.initials: P
authors.lastname: Dijkstra
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Hart
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Hungate
authors.forename: Nichole M
authors.initials: NM
authors.lastname: Flood
authors.forename: Egbert
authors.initials: E
authors.lastname: Schwartz
mesh_terms: D018533:Biomass; D017753:Ecosystem; D004926:Escherichia coli / Q000378:metabolism / Q000502:physiology*; D009584:Nitrogen / Q000378:metabolism*; D009587:Nitrogen Isotopes / Q000378:metabolism
chemical_list: D009587:Nitrogen Isotopes; D009584:Nitrogen