Editor: Juan Imperial
Effects of nitrite on ammonia-oxidizing activity and gene regulation in three ammonia-oxidizing bacteria
Article first published online: 20 APR 2011
© 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved
FEMS Microbiology Letters
Volume 319, Issue 2, pages 169–175, June 2011
How to Cite
Cua, L. S. and Stein, L. Y. (2011), Effects of nitrite on ammonia-oxidizing activity and gene regulation in three ammonia-oxidizing bacteria. FEMS Microbiology Letters, 319: 169–175. doi: 10.1111/j.1574-6968.2011.02277.x
- Issue published online: 17 MAY 2011
- Article first published online: 20 APR 2011
- Accepted manuscript online: 6 APR 2011 08:19AM EST
- Received 7 July 2010; revised 31 March 2011; accepted 31 March 2011., Final version published online 20 April 2011.
- gene expression;
- ammonia oxidation
Nitrite is the highly toxic end product of ammonia oxidation that accumulates in the absence of a nitrite-consuming process and is inhibitory to nitrifying and other bacteria. The effects of nitrite on ammonia oxidation rates and regulation of a common gene set were compared in three ammonia-oxidizing bacteria (AOB) to determine whether responses to this toxic metabolite were uniform. Mid-exponential-phase cells of Nitrosomonas europaea ATCC 19718, Nitrosospira multiformis ATCC 25196, and Nitrosomonas eutropha C-91 were incubated for 6 h in mineral medium supplemented with 0, 10, or 20 mM NaNO2. The rates of ammonia oxidation (nitrite production) decreased significantly only in NaNO2-supplemented incubations of N. eutropha; no significant effect on the rates was observed for N. europaea or N. multiformis. The levels of norB (nitric oxide reductases), cytL (cytochrome P460), and cytS (cytochrome c′-β) mRNA were unaffected by nitrite in all strains. The levels of nirK (nitrite reductase) mRNA increased only in N. europaea in response to nitrite (10 and 20 mM). Nitrite (20 mM) significantly reduced the mRNA levels of amoA (ammonia monooxygenase) in N. multiformis and norS (nitric oxide reductase) in the two Nitrosomonas spp. Differences in response to nitrite indicated nonuniform adaptive and regulatory strategies of AOB, even between closely related species.