Department of Biology

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Susanne Nielsen

Effects of Bacterial Community Members on the Proteome of the Ammonia-Oxidizing Bacterium Nitrosomonas sp Strain Is79

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  • Christopher J. Sedlacek, Univ Vienna, University of Vienna, Div Microbial Ecol
  • ,
  • Susanne Nielsen
  • Kenneth D. Greis, Univ Cincinnati, University of Cincinnati, Dept Canc Biol, Prote Lab
  • ,
  • Wendy D. Haffey, Univ Cincinnati, University of Cincinnati, Dept Canc Biol, Prote Lab
  • ,
  • Niels Peter Revsbech
  • Tomislav Ticak, Univ Idaho, University of Idaho, Dept Biol
  • ,
  • Hendrikus J. Laanbroek, Univ Utrecht, University of Utrecht, Dept Biol Ecol & Biodivers
  • ,
  • Annette Bollmann, Aarhus University

Microorganisms in the environment do not exist as the often-studied pure cultures but as members of complex microbial communities. Characterizing the interactions within microbial communities is essential to understand their function in both natural and engineered environments. In this study, we investigated how the presence of a nitrite-oxidizing bacterium (NOB) and heterotrophic bacteria affect the growth and proteome of the chemolithoautotrophic ammonia-oxidizing bacterium (AOB) Nitrosomonas sp. strain Is79. We investigated Nitrosomonas sp. Is79 in co-culture with Nitrobacter winogradskyi, in co-cultures with selected heterotrophic bacteria, and as a member of the nitrifying enrichment culture G5-7. In batch culture, N. winogradskyi and heterotrophic bacteria had positive effects on the growth of Nitrosomonas sp. Is79. An isobaric tag for relative and absolute quantification (iTRAQ) liquid chromatography-tandem mass spectrometry (LC-MS/MS) proteomics approach was used to investigate the effect of N. winogradskyi and the co-cultured heterotrophic bacteria from G5-7 on the proteome of Nitrosomonas sp. Is79. In co-culture with N. winogradskyi, several Nitrosomonas sp. Is79 oxidative stress response proteins changed in abundance, with periplasmic proteins increasing and cytoplasmic proteins decreasing in abundance. In the presence of heterotrophic bacteria, the abundance of proteins directly related to the ammonia oxidation pathway increased, while the abundance of proteins related to amino acid synthesis and metabolism decreased. In summary, the proteome of Nitrosomonas sp. Is79 was differentially influenced by the presence of either N. winogradskyi or heterotrophic bacteria. Together, N. winogradskyi and heterotrophic bacteria reduced the oxidative stress for Nitrosomonas sp. Is79, which resulted in more efficient metabolism.


Aerobic ammonia-oxidizing microorganisms play an important role in the global nitrogen cycle, converting ammonia to nitrite. In their natural environment, they coexist and interact with nitrite oxidizers, which convert nitrite to nitrate, and with heterotrophic microorganisms. The presence of nitrite oxidizers and heterotrophic bacteria has a positive influence on the growth of the ammonia oxidizers. Here, we present a study investigating the effect of nitrite oxidizers and heterotrophic bacteria on the proteome of a selected ammonia oxidizer in a defined culture to elucidate how these two groups improve the performance of the ammonia oxidizer. The results show that the presence of a nitrite oxidizer and heterotrophic bacteria reduced the stress for the ammonia oxidizer and resulted in more efficient energy generation. This study contributes to our understanding of microbemicrobe interactions, in particular between ammonia oxidizers and their neighboring microbial community.

Original languageEnglish
JournalApplied and Environmental Microbiology
Pages (from-to)4776-4788
Number of pages13
Publication statusPublished - Aug 2016

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