Collins Jessica G, Dijkstra Paul, Hart Stephen C, Hungate Bruce A, Flood Nichole M, Schwartz Egbert
Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA.
FEMS Microbiol Lett. 2008 May;282(2):246-50. doi: 10.1111/j.1574-6968.2008.01133.x. Epub 2008 Apr 9.
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.
通过控制底物碳和氮的可利用性，迫使大肠杆菌细胞在体外矿化或同化氮。当在有机氮源上生长时，大肠杆菌细胞释放出NH₄⁺，并且相对于氮源，细胞中的¹⁵N含量增加（千分比为1.6 - 3.1）。然而，当细胞在无机氮源上生长时，相对于该氮源，生物量中的¹⁵N含量减少（千分比为6.1 - 9.1）。通过测量微生物相对于氮库的¹⁵N富集情况，生态系统生态学家或许能够确定微生物是在同化还是在矿化氮。
