RT Journal Article SR Electronic(1) A1 Schmidt, Ingo A1 Look, Christiane A1 Bock, Eberhard A1 Jetten, Mike S. M.YR 2004 T1 Ammonium and hydroxylamine uptake and accumulation in Nitrosomonas JF Microbiology, VO 150 IS 5 SP 1405 OP 1412 DO https://doi.org/10.1099/mic.0.26719-0 PB Microbiology Society, SN 1465-2080, AB Starved cells of Nitrosomonas europaea and further ammonia oxidizers were able to rapidly accumulate ammonium and hydroxylamine to an internal concentration of about 1 and 0·8 M, respectively. In kinetic studies, the uptake/accumulation rates for ammonium [3·1 mmol (g protein)−1 min−1] and hydroxylamine [4·39 mmol (g protein)−1 min−1] were determined. The uptake and accumulation process of ammonium and hydroxylamine was not coupled to ammonia or hydroxylamine oxidation and nitrite was not produced. In the presence of uncouplers the ammonium accumulation was completely inhibited, indicating an active, membrane-potential-driven transport mechanism. When the external ammonium or hydroxylamine pool was depleted, the internal ammonium and hydroxylamine was consumed within 12 h or 20 min, respectively. The binding of ammonium/ammonia was correlated with an energized membrane system, and hydroxylamine may bind to the hydroxylamine oxidoredutase., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/mic.0.26719-0