PMID- 20202220
OWN - NLM
STAT- MEDLINE
DCOM- 20100614
LR  - 20181113
IS  - 1471-2180 (Electronic)
IS  - 1471-2180 (Linking)
VI  - 10
DP  - 2010 Mar 4
TI  - Strategies of Nitrosomonas europaea 19718 to counter low dissolved oxygen and 
      high nitrite concentrations.
PG  - 70
LID - 10.1186/1471-2180-10-70 [doi]
AB  - BACKGROUND: Nitrosomonas europaea is a widely studied chemolithoautotrophic 
      ammonia oxidizing bacterium. While significant work exists on the ammonia 
      oxidation pathway of N. europaea, its responses to factors such as dissolved 
      oxygen limitation or sufficiency or exposure to high nitrite concentrations, 
      particularly at the functional gene transcription level are relatively sparse. 
      The principal goal of this study was to investigate responses at the whole-cell 
      activity and gene transcript levels in N. europaea 19718 batch cultures, which 
      were cultivated at different dissolved oxygen and nitrite concentrations. 
      Transcription of genes coding for principal metabolic pathways including ammonia 
      oxidation (amoA), hydroxylamine oxidation (hao), nitrite reduction (nirK) and 
      nitric oxide reduction (norB) were quantitatively measured during batch growth, 
      at a range of DO concentrations (0.5, 1.5 and 3.0 mg O2/L). Measurements were 
      also conducted during growth at 1.5 mg O2/L in the presence of 280 mg-N/L of 
      externally added nitrite. RESULTS: Several wide ranging responses to DO 
      limitation and nitrite toxicity were observed in N. europaea batch cultures. In 
      contrast to our initial hypothesis, exponential phase mRNA concentrations of both 
      amoA and hao increased with decreasing DO concentrations, suggesting a mechanism 
      to metabolize ammonia and hydroxylamine more effectively under DO limitation. 
      Batch growth in the presence of 280 mg nitrite-N/L resulted in elevated 
      exponential phase nirK and norB mRNA concentrations, potentially to promote 
      utilization of nitrite as an electron acceptor and to detoxify nitrite. This 
      response was in keeping with our initial hypothesis and congruent with similar 
      responses in heterotrophic denitrifying bacteria. Stationary phase responses were 
      distinct from exponential phase responses in most cases, suggesting a strong 
      impact of ammonia availability and metabolism on responses to DO limitation and 
      nitrite toxicity. In general, whole-cell responses to DO limitation or nitrite 
      toxicity, such as sOUR or nitrite reduction to nitric oxide (NO) did not parallel 
      the corresponding mRNA (nirK) profiles, suggesting differences between the gene 
      transcription and enzyme translation or activity levels. CONCLUSIONS: The results 
      of this study show that N. europaea possesses specific mechanisms to cope with 
      growth under low DO concentrations and high nitrite concentrations. These 
      mechanisms are additionally influenced by the physiological growth state of N. 
      europaea cultures and are possibly geared to enable more efficient substrate 
      utilization or nitrite detoxification.
FAU - Yu, Ran
AU  - Yu R
AD  - Department of Earth and Environmental Engineering, Columbia University, New York, 
      NY 10027, USA.
FAU - Chandran, Kartik
AU  - Chandran K
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20100304
PL  - England
TA  - BMC Microbiol
JT  - BMC microbiology
JID - 100966981
RN  - 0 (Nitrites)
RN  - S88TT14065 (Oxygen)
SB  - IM
MH  - Aerobiosis
MH  - Anaerobiosis
MH  - Cell Proliferation
MH  - Gene Expression Regulation, Bacterial
MH  - Kinetics
MH  - Nitrites/analysis/*metabolism
MH  - Nitrosomonas europaea/genetics/*metabolism
MH  - Oxidation-Reduction
MH  - Oxygen/analysis/*metabolism
MH  - Polymerase Chain Reaction
MH  - Transcription, Genetic
PMC - PMC2844404
EDAT- 2010/03/06 06:00
MHDA- 2010/06/15 06:00
PMCR- 2010/03/04
CRDT- 2010/03/06 06:00
PHST- 2009/09/03 00:00 [received]
PHST- 2010/03/04 00:00 [accepted]
PHST- 2010/03/06 06:00 [entrez]
PHST- 2010/03/06 06:00 [pubmed]
PHST- 2010/06/15 06:00 [medline]
PHST- 2010/03/04 00:00 [pmc-release]
AID - 1471-2180-10-70 [pii]
AID - 10.1186/1471-2180-10-70 [doi]
PST - epublish
SO  - BMC Microbiol. 2010 Mar 4;10:70. doi: 10.1186/1471-2180-10-70.