Transcript profiles of Nitrosomonas europaea during growth and upon deprivation of ammonia and carbonate


  • Editor: J. C. Murrell

Correspondence: Daniel J. Arp, Department of Botany and Plant Pathology, Oregon State University, Corvallis, OR 97331, USA. Tel.: +1 541 737 1294; fax: +1 541 737 5310; e-mail:


The transcriptome of Nitrosomonas europaea was analyzed with whole-genome microarrays. Growing cells were compared to cells deprived of (NH4)2SO4 and Na2CO3. Hybridization signals were detected for 76% of the genes represented on the array under either or both conditions. Transcript levels for 68% of the genes were at least twofold higher in growing cells than in deprived cells, while only 0.42% of the genes were present at more than twofold higher levels in deprived cells. Transcript levels for the remaining 7% of the genes did not change significantly with the treatments. These trends were confirmed for selected genes by Northern hybridizations and quantitative RT-PCR. Compared to heterotrophic bacteria, N. europaea downregulates a greater proportion of its genes and fewer genes appear to be associated with the adaptation to starvation.