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Influence of copper on expression of nirS, norB and nosZ and the transcription and activity of NIR, NOR and N2 OR in the denitrifying soil bacteria Pseudomonas stutzeri.

Black A, Hsu PC, Hamonts KE, Clough TJ, Condron LM - Microb Biotechnol (2016)

Bottom Line: Results revealed that 0.05 mM Cu caused maximum conversion of N(2)O to N(2) via bacterial reduction of N(2)O.As soluble Cu generally makes up less than 0.001% of total soil Cu, extrapolation of 0.05 mg l(-l) soluble Cu would require soils to have a total concentration of Cu in the range of, 150-200 μg g(-1) to maximize the proportion of N(2)O reduced to N(2).Given that many intensively farmed agricultural soils are deficient in Cu in terms of plant nutrition, providing a sufficient concentration of biologically accessible Cu could provide a potentially useful microbial-based strategy of reducing agricultural N(2)O emissions.

View Article: PubMed Central - PubMed

Affiliation: Bio Protection Research Centre, Lincoln University, PO Box 85084, Lincoln, Christchurch, 7647, New Zealand.

No MeSH data available.


Related in: MedlinePlus

Nitrate is reduced to nitrogen gas under anaerobic condition via the denitrification process of Pseudomonas stutzeri. Arrows indicate an operon or gene required for each reaction to occur with metal cofactor requisite for the enzyme complex.
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mbt212352-fig-0001: Nitrate is reduced to nitrogen gas under anaerobic condition via the denitrification process of Pseudomonas stutzeri. Arrows indicate an operon or gene required for each reaction to occur with metal cofactor requisite for the enzyme complex.

Mentions: Nitrous oxide accounts for ~10% of the total greenhouse gas emissions and is produced as a by‐product of bacterial and fungal respiration pathways in soil. Both denitrification and nitrification respiratory pathways emit N2O with rates increasing with the addition of N fertilizer (Taylor and Townsend, 2010; Magalhaes et al., 2011). Denitrification occurs when oxygen (O2) is in limited supply and bacteria with denitrifying capability can switch to respiring nitrate (NO3−), converting NO3− to nitrite (NO2−) and the gases nitric oxide (NO) and N2O and finally dinitrogen (N2) (Fig. 1). This process requires four enzymes to sequentially reduce NO3− to N2 with each of these enzymes requiring a redox metal cofactor (Fig. 1). Denitrifying soil bacteria such as Pseudomonas stutzeri generate N2O via the reduction of NO, an endogenous cytotoxin, by reducing N2O via the enzyme nitric oxide reductase (NOR), hence bacteria deficient in NOR cannot grow through denitrification (Zumft, 2005a,b). Because so much N2O is produced from soils carrying out bacterial denitrification, it implies that the bacterial enzyme nitrous oxide reductase (N2OR), or the bacterial population as a whole, do not always carry out the reduction of N2O to N2 efficiently or in synchrony with pathways upstream (i.e. nitrifier‐denitrification) (Richardson et al., 2009). Thus, managing N2O emissions requires consideration of the factors affecting the production of N2O at both the molecular and soil microbial ecology levels.


Influence of copper on expression of nirS, norB and nosZ and the transcription and activity of NIR, NOR and N2 OR in the denitrifying soil bacteria Pseudomonas stutzeri.

Black A, Hsu PC, Hamonts KE, Clough TJ, Condron LM - Microb Biotechnol (2016)

Nitrate is reduced to nitrogen gas under anaerobic condition via the denitrification process of Pseudomonas stutzeri. Arrows indicate an operon or gene required for each reaction to occur with metal cofactor requisite for the enzyme complex.
© Copyright Policy - creativeCommonsBy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4835574&req=5

mbt212352-fig-0001: Nitrate is reduced to nitrogen gas under anaerobic condition via the denitrification process of Pseudomonas stutzeri. Arrows indicate an operon or gene required for each reaction to occur with metal cofactor requisite for the enzyme complex.
Mentions: Nitrous oxide accounts for ~10% of the total greenhouse gas emissions and is produced as a by‐product of bacterial and fungal respiration pathways in soil. Both denitrification and nitrification respiratory pathways emit N2O with rates increasing with the addition of N fertilizer (Taylor and Townsend, 2010; Magalhaes et al., 2011). Denitrification occurs when oxygen (O2) is in limited supply and bacteria with denitrifying capability can switch to respiring nitrate (NO3−), converting NO3− to nitrite (NO2−) and the gases nitric oxide (NO) and N2O and finally dinitrogen (N2) (Fig. 1). This process requires four enzymes to sequentially reduce NO3− to N2 with each of these enzymes requiring a redox metal cofactor (Fig. 1). Denitrifying soil bacteria such as Pseudomonas stutzeri generate N2O via the reduction of NO, an endogenous cytotoxin, by reducing N2O via the enzyme nitric oxide reductase (NOR), hence bacteria deficient in NOR cannot grow through denitrification (Zumft, 2005a,b). Because so much N2O is produced from soils carrying out bacterial denitrification, it implies that the bacterial enzyme nitrous oxide reductase (N2OR), or the bacterial population as a whole, do not always carry out the reduction of N2O to N2 efficiently or in synchrony with pathways upstream (i.e. nitrifier‐denitrification) (Richardson et al., 2009). Thus, managing N2O emissions requires consideration of the factors affecting the production of N2O at both the molecular and soil microbial ecology levels.

Bottom Line: Results revealed that 0.05 mM Cu caused maximum conversion of N(2)O to N(2) via bacterial reduction of N(2)O.As soluble Cu generally makes up less than 0.001% of total soil Cu, extrapolation of 0.05 mg l(-l) soluble Cu would require soils to have a total concentration of Cu in the range of, 150-200 μg g(-1) to maximize the proportion of N(2)O reduced to N(2).Given that many intensively farmed agricultural soils are deficient in Cu in terms of plant nutrition, providing a sufficient concentration of biologically accessible Cu could provide a potentially useful microbial-based strategy of reducing agricultural N(2)O emissions.

View Article: PubMed Central - PubMed

Affiliation: Bio Protection Research Centre, Lincoln University, PO Box 85084, Lincoln, Christchurch, 7647, New Zealand.

No MeSH data available.


Related in: MedlinePlus