IV.—On nitrification

Warington, Robert

doi:10.1039/ct8783300044

Cited by 34 publications

(15 citation statements)

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“…The nitrifier Nitrosomonas europaea was shown to have CS 2 conversion activity, but the mechanism of CS 2 conversion was not investigated (56). CS 2 is one of the oldest known inhibitors of nitrification (57). The inhibitory action has been attributed to the CS 2 molecule forming a complex with a nucleophilic amino acid close to the active center of AMO, thereby chelating the Cu cofactor from the active center (58,59).…”

Section: Discussionmentioning

confidence: 99%

Bacterial CS2 Hydrolases from Acidithiobacillus thiooxidans Strains Are Homologous to the Archaeal Catenane CS2 Hydrolase

Smeulders

Pol

Venselaar³

et al. 2013

Journal of Bacteriology

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c Carbon disulfide (CS 2 ) and carbonyl sulfide (COS) are important in the global sulfur cycle, and CS 2 is used as a solvent in the viscose industry. These compounds can be converted by sulfur-oxidizing bacteria, such as Acidithiobacillus thiooxidans species, to carbon dioxide (CO 2 ) and hydrogen sulfide (H 2 S), a property used in industrial biofiltration of CS 2 -polluted airstreams. We report on the mechanism of bacterial CS 2 conversion in the extremely acidophilic A. thiooxidans strains S1p and G8. The bacterial CS 2 hydrolases were highly abundant. They were purified and found to be homologous to the only other described (archaeal) CS 2 hydrolase from Acidianus strain A1-3, which forms a catenane of two interlocked rings. The enzymes cluster in a group of ␤-carbonic anhydrase (␤-CA) homologues that may comprise a subclass of CS 2 hydrolases within the ␤-CA family. Unlike CAs, the CS 2 hydrolases did not hydrate CO 2 but converted CS 2 and COS with H 2 O to H 2 S and CO 2 . The CS 2 hydrolases of A. thiooxidans strains G8, 2Bp, Sts 4-3, and BBW1, like the CS 2 hydrolase of Acidianus strain A1-3, exist as both octamers and hexadecamers in solution. The CS 2 hydrolase of A. thiooxidans strain S1p forms only octamers. Structure models of the A. thiooxidans CS 2 hydrolases based on the structure of Acidianus strain A1-3 CS 2 hydrolase suggest that the A. thiooxidans strain G8 CS 2 hydrolase may also form a catenane. In the A. thiooxidans strain S1p enzyme, two insertions (positions 26 and 27 [PD] and positions 56 to 61 [TPAGGG]) and a nine-amino-acid-longer C-terminal tail may prevent catenane formation.

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Section: Discussionmentioning

confidence: 99%

Bacterial CS2 Hydrolases from Acidithiobacillus thiooxidans Strains Are Homologous to the Archaeal Catenane CS2 Hydrolase

Smeulders

Pol

Venselaar³

et al. 2013

Journal of Bacteriology

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“…Chemolithotrophic nitrification is a two-step process, consisting of the conversion of ammonia to nitrite, which is in turn converted to nitrate. These steps are carried out by two different groups of organisms, the ammonia-oxidizing bacteria and the nitrite-oxidizing bacteria (AOB and NOB), respectively (205,211). There are no known autotrophic bacteria that can catalyze the production of nitrate from ammonia.…”

Section: Chemolitho-autotrophic Ammonia Oxidationmentioning

confidence: 99%

Ammonia-Oxidizing Bacteria: A Model for Molecular Microbial Ecology

Kowalchuk

Stephen²

2001

Annu. Rev. Microbiol.

1,138

725

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The eutrophication of many ecosystems in recent decades has led to an increased interest in the ecology of nitrogen transformation. Chemolitho-autotrophic ammonia-oxidizing bacteria are responsible for the rate-limiting step of nitrification in a wide variety of environments, making them important in the global cycling of nitrogen. These organisms are unique in their ability to use the conversion of ammonia to nitrite as their sole energy source. Because of the importance of this functional group of bacteria, understanding of their ecology and physiology has become a subject of intense research over recent years. The monophyletic nature of these bacteria in terrestrial environments has facilitated molecular biological approaches in studying their ecology, and progress in this field has been rapid. The ammonia-oxidizing bacteria of the beta-subclass Proteobacteria have become somewhat of a model system within molecular microbial ecology, and this chapter reviews recent progress in our knowledge of their distribution, diversity, and ecology.

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“…One of the oldest known inhibitors of nitrification is carbon disulfide (CS2), which was first reported by Warrington (31). Even before Warrington's work, CS2 had been used as a soil fumigant and its effects on nitrification had been recognized.…”

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confidence: 99%

Inhibition of ammonia monooxygenase in Nitrosomonas europaea by carbon disulfide

1990

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Carbon disulfide has long been recognized as a potent inhibitor of nitrification, and it is the likely active component in several nitrification inhibitors suitable for field use. The effects of this compound on Nitrosomonas europaea have been investigated, and the site of action has been determined. Low concentrations of CS2 (<400 ,uM) produced a time-dependent inhibition of ammonia-dependent O2 uptake but did not inhibit hydrazineoxidizing activity. CS2 also produced distinct changes in difference spectra of whole cells. These results suggest that ammonia monooxygenase (AMO) is the site of action of CS2. Unlike the case for thiourea and acetylene, saturating concentrations of CS2 did not fully inhibit AMO, and the inhibition resulted in a low but significant rate of ammonia-dependent 02 uptake. The effects of CS2 were not competitive with respect to ammonia concentration, and the inhibition by CS2 did not require the turnover of AMO to take effect. The ability of CS2-treated cells to incorporate [14C]acetylene into the 28-kilodalton polypeptide of AMO was used to demonstrate that the effects of CS2 are compatible with a mode of action which involves a reduction of the rate of turnover of AMO without effects on the catalytic mechanism. It is proposed that CS2 may act on AMO by reversibly reacting with a suitable nucleophilic amino acid in close proximity to the active site copper.The major process in microbial nitrification is the oxidation of ammonia to nitrite, followed by the oxidation of nitrite to nitrate. These reactions are predominantly catalyzed by specialized autotrophic bacteria characterized by such species as the ammonia-oxidizing bacterium Nitrosomonas europaea and the nitrite-oxidizing bacterium Nitrobacter winogradskyi, respectively. Although our understanding of the biochemistry and enzymology of individual reactions in the nitrification process is far from complete, there is a considerable general interest in nitrification because it plays an important role in controlling the balance between fixed and mobile forms of nitrogen in soil and water systems. For example, in agriculture, nitrification can lead to substantial losses of costly ammonia-based fertilizer (and urea-based fertilizer, which hydrolyzes to ammonia) because both nitrification products, nitrite and nitrate, are easily leached from soils by water. In addition, nitrate is the major substrate for denitrifying bacteria that generate gaseous products (N20, NO, and N2) which are lost to the atmosphere. These same reactions, while detrimental to agriculture, are regarded as positive benefits in water treatment regimens, in which the objective is to reduce the nitrogen content of waste waters (22).Because it is ammonia-oxidizing bacteria that initiate nitrification as a whole, there has been considerable research into the inhibition of this process. Ammonia oxidation by N. europaea is a two-stage process that is now thought to involve the initial oxidation of ammonia to hydroxylamine by a membrane-bound enzyme known as ammonia monooxyge...

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IV.—On nitrification

Cited by 34 publications

References 0 publications

Bacterial CS2 Hydrolases from Acidithiobacillus thiooxidans Strains Are Homologous to the Archaeal Catenane CS2 Hydrolase

Bacterial CS2 Hydrolases from Acidithiobacillus thiooxidans Strains Are Homologous to the Archaeal Catenane CS2 Hydrolase

Ammonia-Oxidizing Bacteria: A Model for Molecular Microbial Ecology

Inhibition of ammonia monooxygenase in Nitrosomonas europaea by carbon disulfide

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