Geographic Distribution of Ammonia-Oxidizing Archaea along the Kuril Islands in the Western Subarctic Pacific

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Hongmei Jing

2017-06-01

Full Text Available Community composition and abundance of ammonia-oxidizing archaea (AOA in the ocean were affected by different physicochemical conditions, but their responses to physical barriers (such as a chain of islands were largely unknown. In our study, geographic distribution of the AOA from the surface photic zone to the deep bathypelagic waters in the western subarctic Pacific adjacent to the Kuril Islands was investigated using pyrosequencing based on the ammonia monooxygenase subunit A (amoA gene. Genotypes of clusters A and B dominated in the upper euphotic zone and the deep waters, respectively. Quantitative PCR assays revealed that the occurrence and ammonia-oxidizing activity of ammonia-oxidizing archaea (AOA reached their maxima at the depth of 200 m, where a higher diversity and abundance of actively transcribed AOA was observed at the station located in the marginal sea exposed to more terrestrial input. Similar community composition of AOA observed at the two stations adjacent to the Kuril Islands maybe due to water exchange across the Bussol Strait. They distinct from the station located in the western subarctic gyre, where sub-cluster WCAII had a specific distribution in the surface water, and this sub-cluster seemed having a confined distribution in the western Pacific. Habitat-specific groupings of different WCB sub-clusters were observed reflecting the isolated microevolution existed in cluster WCB. The effect of the Kuril Islands on the phylogenetic composition of AOA between the Sea of Okhotsk and the western subarctic Pacific is not obvious, possibly because our sampling stations are near to the Bussol Strait, the main gateway through which water is exchanged between the Sea of Okhotsk and the Pacific. The vertical and horizontal distribution patterns of AOA communities among stations along the Kuril Islands were essentially determined by the in situ prevailing physicochemical gradients along the two dimensions.

[Distribution and Diversity of Ammonium-oxidizing Archaea and Ammonium-oxidizing Bacteria in Surface Sediments of Oujiang River].

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Li, Hu; Huang, Fu-yi; Su, Jian-qiang; Hong, You-wei; Yu, Shen

2015-12-01

Ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) play important roles in the biogeochemical nitrogen cycle. Rivers are important ecosystems containing a large number of functional microbes in nitrogen cycle. In this study, denaturing gradient gel electrophoresis (DGGE ) and real-time quantitative PCR (qPCR) technology were used to analyze the distribution and diversity of AOA and AOB in sediments from Oujiang. The results showed that the AOA community structure was similar among various sites, while the AOB community structure was significantly different, in which all detected AOB sequences were classified into Nitrosospira and Nitrosomonas, and 90% affiliated to Nitrosospira. The community composition of AOA was influenced by NH₄⁺ and TS, in addition, the AOB composition was affected by NH₄⁺, EC, pH, NO₃⁻, TC and TN. Total sulfur (TS) and electrical conductivity (EC) were the major factors influencing the diversity of AOA and AOB, respectively. AOA abundance was significantly higher than that of AOB. EC, NH₄⁺-N and NO₃⁻-N were the main environmental factors affecting the abundance of AOA and AOB. This study indicated that the community composition and diversity of AOA and AOB were significantly influenced by environmental factors, and AOA might be dominant drivers in the ammonia oxidation process in Oujiang surface sediment.

Influence of land use intensity on the diversity of ammonia oxidizing bacteria and archaea in soils from grassland ecosystems.

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Meyer, Annabel; Focks, Andreas; Radl, Viviane; Welzl, Gerhard; Schöning, Ingo; Schloter, Michael

2014-01-01

In the present study, the influence of the land use intensity on the diversity of ammonia oxidizing bacteria (AOB) and archaea (AOA) in soils from different grassland ecosystems has been investigated in spring and summer of the season (April and July). Diversity of AOA and AOB was studied by TRFLP fingerprinting of amoA amplicons. The diversity from AOB was low and dominated by a peak that could be assigned to Nitrosospira. The obtained profiles for AOB were very stable and neither influenced by the land use intensity nor by the time point of sampling. In contrast, the obtained patterns for AOA were more complex although one peak that could be assigned to Nitrosopumilus was dominating all profiles independent from the land use intensity and the sampling time point. Overall, the AOA profiles were much more dynamic than those of AOB and responded clearly to the land use intensity. An influence of the sampling time point was again not visible. Whereas AOB profiles were clearly linked to potential nitrification rates in soil, major TRFs from AOA were negatively correlated to DOC and ammonium availability and not related to potential nitrification rates.

Growth of ammonia-oxidizing archaea and bacteria in cattle manure compost under various temperatures and ammonia concentrations.

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Oishi, Ryu; Tada, Chika; Asano, Ryoki; Yamamoto, Nozomi; Suyama, Yoshihisa; Nakai, Yutaka

2012-05-01

A recent study showed that ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) coexist in the process of cattle manure composting. To investigate their physiological characteristics, liquid cultures seeded with fermenting cattle manure compost were incubated at various temperatures (37°C, 46°C, or 60°C) and ammonium concentrations (0.5, 1, 4, or 10 mM NH (4) (+) -N). The growth rates of the AOB and AOA were monitored using real-time polymerase chain reaction analysis targeting the bacterial and archaeal ammonia monooxygenase subunit A genes. AOB grew at 37°C and 4 or 10 mM NH (4) (+) -N, whereas AOA grew at 46°C and 10 mM NH (4) (+) -N. Incubation with allylthiourea indicated that the AOB and AOA grew by oxidizing ammonia. Denaturing gradient gel electrophoresis and subsequent sequencing analyses revealed that a bacterium related to Nitrosomonas halophila and an archaeon related to Candidatus Nitrososphaera gargensis were the predominant AOB and AOA, respectively, in the seed compost and in cultures after incubation. This is the first report to demonstrate that the predominant AOA in cattle manure compost can grow and can probably oxidize ammonia under moderately thermophilic conditions.

Large cryoconite aggregates on a Svalbard glacier support a diverse microbial community including ammonia-oxidizing archaea

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Zarsky, Jakub D.; Stibal, Marek; Hodson, Andy; Sattler, Birgit; Schostag, Morten; Hansen, Lars H.; Jacobsen, Carsten S.; Psenner, Roland

2013-09-01

The aggregation of surface debris particles on melting glaciers into larger units (cryoconite) provides microenvironments for various microorganisms and metabolic processes. Here we investigate the microbial community on the surface of Aldegondabreen, a valley glacier in Svalbard which is supplied with carbon and nutrients from different sources across its surface, including colonies of seabirds. We used a combination of geochemical analysis (of surface debris, ice and meltwater), quantitative polymerase chain reactions (targeting the 16S ribosomal ribonucleic acid and amoA genes), pyrosequencing and multivariate statistical analysis to suggest possible factors driving the ecology of prokaryotic microbes on the surface of Aldegondabreen and their potential role in nitrogen cycling. The combination of high nutrient input with subsidy from the bird colonies, supraglacial meltwater flow and the presence of fine, clay-like particles supports the formation of centimetre-scale cryoconite aggregates in some areas of the glacier surface. We show that a diverse microbial community is present, dominated by the cyanobacteria, Proteobacteria, Bacteroidetes, and Actinobacteria, that are well-known in supraglacial environments. Importantly, ammonia-oxidizing archaea were detected in the aggregates for the first time on an Arctic glacier.

Large cryoconite aggregates on a Svalbard glacier support a diverse microbial community including ammonia-oxidizing archaea

International Nuclear Information System (INIS)

Zarsky, Jakub D; Sattler, Birgit; Psenner, Roland; Stibal, Marek; Schostag, Morten; Jacobsen, Carsten S; Hodson, Andy; Hansen, Lars H

2013-01-01

The aggregation of surface debris particles on melting glaciers into larger units (cryoconite) provides microenvironments for various microorganisms and metabolic processes. Here we investigate the microbial community on the surface of Aldegondabreen, a valley glacier in Svalbard which is supplied with carbon and nutrients from different sources across its surface, including colonies of seabirds. We used a combination of geochemical analysis (of surface debris, ice and meltwater), quantitative polymerase chain reactions (targeting the 16S ribosomal ribonucleic acid and amoA genes), pyrosequencing and multivariate statistical analysis to suggest possible factors driving the ecology of prokaryotic microbes on the surface of Aldegondabreen and their potential role in nitrogen cycling. The combination of high nutrient input with subsidy from the bird colonies, supraglacial meltwater flow and the presence of fine, clay-like particles supports the formation of centimetre-scale cryoconite aggregates in some areas of the glacier surface. We show that a diverse microbial community is present, dominated by the cyanobacteria, Proteobacteria, Bacteroidetes, and Actinobacteria, that are well-known in supraglacial environments. Importantly, ammonia-oxidizing archaea were detected in the aggregates for the first time on an Arctic glacier. (letter)

Large cryoconite aggregates on a Svalbard glacier support a diverse microbial community including ammonia-oxidizing archaea

Energy Technology Data Exchange (ETDEWEB)

Zarsky, Jakub D; Sattler, Birgit; Psenner, Roland [Institute of Ecology, University of Innsbruck, Innsbruck (Austria); Stibal, Marek; Schostag, Morten; Jacobsen, Carsten S [Department of Geochemistry, Geological Survey of Denmark and Greenland (GEUS), Copenhagen (Denmark); Hodson, Andy [Department of Geography, University of Sheffield, Sheffield (United Kingdom); Hansen, Lars H, E-mail: j.zarsky@gmail.com [Department of Biology, University of Copenhagen, Copenhagen (Denmark)

2013-09-15

The aggregation of surface debris particles on melting glaciers into larger units (cryoconite) provides microenvironments for various microorganisms and metabolic processes. Here we investigate the microbial community on the surface of Aldegondabreen, a valley glacier in Svalbard which is supplied with carbon and nutrients from different sources across its surface, including colonies of seabirds. We used a combination of geochemical analysis (of surface debris, ice and meltwater), quantitative polymerase chain reactions (targeting the 16S ribosomal ribonucleic acid and amoA genes), pyrosequencing and multivariate statistical analysis to suggest possible factors driving the ecology of prokaryotic microbes on the surface of Aldegondabreen and their potential role in nitrogen cycling. The combination of high nutrient input with subsidy from the bird colonies, supraglacial meltwater flow and the presence of fine, clay-like particles supports the formation of centimetre-scale cryoconite aggregates in some areas of the glacier surface. We show that a diverse microbial community is present, dominated by the cyanobacteria, Proteobacteria, Bacteroidetes, and Actinobacteria, that are well-known in supraglacial environments. Importantly, ammonia-oxidizing archaea were detected in the aggregates for the first time on an Arctic glacier. (letter)

Enrichment of Thermophilic Ammonia-Oxidizing Archaea from an Alkaline Hot Spring in the Great Basin, USA

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Zhang, C.; Huang, Z.; Jiang, H.; Wiegel, J.; Li, W.; Dong, H.

2010-12-01

One of the major advances in the nitrogen cycle is the recent discovery of ammonia oxidation by archaea. While culture-independent studies have revealed occurrence of ammonia-oxidizing archaea (AOA) in nearly every surface niche on earth, most of these microorganisms have resisted isolation and so far only a few species have been identified. The Great Basin contains numerous hot springs, which are characterized by moderately high temperature (40-65 degree C) and circumneutral or alkaline pH. Unique thermophilic archaea have been identified based on molecular DNA and lipid biomarkers; some of which may be ammonia oxidizers. This study aims to isolate some of these archaea from a California hot spring that has pH around 9.0 and temperature around 42 degree C. Mat material was collected from the spring and transported on ice to the laboratory. A synthetic medium (SCM-5) was inoculated with the mat material and the culture was incubated under varying temperature (35-65 degree C) and pH (7.0-10.0) conditions using antibiotics to suppress bacterial growth. Growth of the culture was monitored by microscopy, decrease in ammonium and increase in nitrite, and increases in Crenarchaeota and AOA abundances over time. Clone libraries were constructed to compare archaeal community structures before and after the enrichment experiment. Temperature and pH profiles indicated that the culture grew optimally at pH 9.0 and temperature 45 degree C, which are consistent with the geochemical conditions of the natural environment. Phylogenetic analysis showed that the final OTU was distantly related to all known hyperthermophilic archaea. Analysis of the amoA genes showed two OTUs in the final culture; one of them was closely related to Candidatus Nitrososphaera gargensis. However, the enrichment culture always contained bacteria and attempts to separate them from archaea have failed. This highlights the difficulty in bringing AOA into pure culture and suggests that some of the AOA may

Shifts in the pelagic ammonia-oxidizing microbial communities along the eutrophic estuary of Yong River in Ningbo City, China

NARCIS (Netherlands)

Zhang, Qiufang; Tang, Fang-Yuan; Zhou, Yang-Jing; Xu, Jirong; Chen, Heping; Wang, Ming-Juang; Laanbroek, H.J.

2015-01-01

BACKGROUND: Aerobic ammonia oxidation plays a key role in the nitrogen cycle, and the diversity of the responsible microorganisms is regulated by environmental factors. Abundance and composition of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) were investigated in the surface

Shifts in Abundance and Diversity of Soil Ammonia-Oxidizing Bacteria and Archaea Associated with Land Restoration in a Semi-Arid Ecosystem.

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Zhu Chen

Full Text Available The Grain to Green Project (GGP is an unprecedented land restoration action in China. The project converted large areas (ca 10 million ha of steep-sloped/degraded farmland and barren land into forest and grassland resulting in ecological benefits such as a reduction in severe soil erosion. It may also affect soil microorganisms involved in ammonia oxidization, which is a key step in the global nitrogen cycle. The methods for restoration that are typically adopted in semi-arid regions include abandoning farmland and growing drought tolerant grass (Lolium perenne L. or shrubs (Caragana korshinskii Kom.. In the present study, the effects of these methods on the abundance and diversity of ammonia-oxidizing bacteria (AOB and ammonia-oxidizing archaea (AOA were evaluated via quantitative real-time PCR, terminal restriction fragment length polymorphism and clone library analysis of amoA genes. Comparisons were made between soil samples from three restored lands and the adjacent farmland in Inner Mongolia. Both the abundance and community composition of AOB were significantly different between the restored lands and the adjacent control. Significantly lower nitrification activity was observed for the restored land. Clone library analysis revealed that all AOB amoA gene sequences were affiliated with Nitrosospira. Abundance of the populations that were associated with Nitrosospira sp. Nv6 which had possibly adapted to high concentrations of inorganic nitrogen, decreased on the restored land. Only a slight difference in the AOB communities was observed between the restored land with and without the shrub (Caragana korshinskii Kom.. A minor effect of land restoration on AOA was observed. In summary, land restoration negatively affected the abundance of AOB and soil nitrification activities, suggesting the potential role of GGP in the leaching of nitrates, and in the emission of N2O in related terrestrial ecosystems.

Aerobic nitrous oxide production through N-nitrosating hybrid formation in ammonia-oxidizing archaea.

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Stieglmeier, Michaela; Mooshammer, Maria; Kitzler, Barbara; Wanek, Wolfgang; Zechmeister-Boltenstern, Sophie; Richter, Andreas; Schleper, Christa

2014-05-01

Soil emissions are largely responsible for the increase of the potent greenhouse gas nitrous oxide (N2O) in the atmosphere and are generally attributed to the activity of nitrifying and denitrifying bacteria. However, the contribution of the recently discovered ammonia-oxidizing archaea (AOA) to N2O production from soil is unclear as is the mechanism by which they produce it. Here we investigate the potential of Nitrososphaera viennensis, the first pure culture of AOA from soil, to produce N2O and compare its activity with that of a marine AOA and an ammonia-oxidizing bacterium (AOB) from soil. N. viennensis produced N2O at a maximum yield of 0.09% N2O per molecule of nitrite under oxic growth conditions. N2O production rates of 4.6±0.6 amol N2O cell(-1) h(-1) and nitrification rates of 2.6±0.5 fmol NO2(-) cell(-1) h(-1) were in the same range as those of the AOB Nitrosospira multiformis and the marine AOA Nitrosopumilus maritimus grown under comparable conditions. In contrast to AOB, however, N2O production of the two archaeal strains did not increase when the oxygen concentration was reduced, suggesting that they are not capable of denitrification. In (15)N-labeling experiments we provide evidence that both ammonium and nitrite contribute equally via hybrid N2O formation to the N2O produced by N. viennensis under all conditions tested. Our results suggest that archaea may contribute to N2O production in terrestrial ecosystems, however, they are not capable of nitrifier-denitrification and thus do not produce increasing amounts of the greenhouse gas when oxygen becomes limiting.

Archaea produce lower yields of N2 O than bacteria during aerobic ammonia oxidation in soil.

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Hink, Linda; Nicol, Graeme W; Prosser, James I

2017-12-01

Nitrogen fertilisation of agricultural soil contributes significantly to emissions of the potent greenhouse gas nitrous oxide (N 2 O), which is generated during denitrification and, in oxic soils, mainly by ammonia oxidisers. Although laboratory cultures of ammonia oxidising bacteria (AOB) and archaea (AOA) produce N 2 O, their relative activities in soil are unknown. This work tested the hypothesis that AOB dominate ammonia oxidation and N 2 O production under conditions of high inorganic ammonia (NH 3 ) input, but result mainly from the activity of AOA when NH 3 is derived from mineralisation. 1-octyne, a recently discovered inhibitor of AOB, was used to distinguish N 2 O production resulting from archaeal and bacterial ammonia oxidation in soil microcosms, and specifically inhibited AOB growth, activity and N 2 O production. In unamended soils, ammonia oxidation and N 2 O production were lower and resulted mainly from ammonia oxidation by AOA. The AOA N 2 O yield relative to nitrite produced was half that of AOB, likely due to additional enzymatic mechanisms in the latter, but ammonia oxidation and N 2 O production were directly linked in all treatments. Relative contributions of AOA and AOB to N 2 O production, therefore, reflect their respective contributions to ammonia oxidation. These results suggest potential mitigation strategies for N 2 O emissions from fertilised agricultural soils. © 2016 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd.

Community Structure of Ammonia-Oxidizing Archaea and Ammonia-Oxidizing Bacteria in Soil Treated with the Insecticide Imidacloprid

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Mariusz Cycoń

2015-01-01

Full Text Available The purpose of this experiment was to assess the effect of imidacloprid on the community structure of ammonia-oxidizing archaea (AOA and ammonia-oxidizing bacteria (AOB in soil using the denaturing gradient gel electrophoresis (DGGE approach. Analysis showed that AOA and AOB community members were affected by the insecticide treatment. However, the calculation of the richness (S and the Shannon-Wiener index (H values for soil treated with the field rate (FR dosage of imidacloprid (1 mg/kg soil showed no changes in measured indices for the AOA and AOB community members. In turn, the 10*FR dosage of insecticide (10 mg/kg soil negatively affected the AOA community, which was confirmed by the decrease of the S and H values in comparison with the values obtained for the control soil. In the case of AOB community, an initial decline followed by the increase of the S and H values was obtained. Imidacloprid decreased the nitrification rate while the ammonification process was stimulated by the addition of imidacloprid. Changes in the community structure of AOA and AOB could be due to an increase in the concentration of N-NH4+, known as the most important factor which determines the contribution of these microorganisms to soil nitrification.

Substrate availability drives spatial patterns in richness of ammonia-oxidizing bacteria and archaea in temperate forest soils

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J.S. Norman; J.E. Barrett

2016-01-01

We sought to investigate the drivers of richness of ammonia-oxidizing bacteria (AOB) and archaea (AOA) in temperate forest soils. We sampled soils across four experimental watersheds in the Coweeta Hydrologic Laboratory, North Carolina USA. These watersheds are geographically close, but vary in soil chemistry due to differences in land use history. While we...

Comparison of the Effects of Phenylhydrazine Hydrochloride and Dicyandiamide on Ammonia-Oxidizing Bacteria and Archaea in Andosols

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Wenjie Yang

2017-11-01

Full Text Available Dicyandiamide, a routinely used commercial nitrification inhibitor (NI, inhibits ammonia oxidation catalyzed by ammonia monooxygenase (AMO. Phenylhydrazine hydrochloride has shown considerable potential for the development of next-generation NIs targeting hydroxylamine dehydrogenase (HAO. The effects of the AMO inhibitor and the HAO inhibitor on ammonia-oxidizing bacteria (AOB and ammonia-oxidizing archaea (AOA present in agricultural soils have not been compared thus far. In the present study, the effects of the two inhibitors on soil nitrification and the abundance of AOA and AOB as well as their community structure were investigated in a soil microcosm using quantitative polymerase chain reaction and pyrosequencing. The net nitrification rates and the growth of AOA and AOB in this soil microcosm were inhibited by both NIs. Both NIs had limited effect on the community structure of AOB and no effect on that of AOA in this soil microcosm. The effects of phenylhydrazine hydrochloride were similar to those of dicyandiamide. These results indicated that organohydrazine-based NIs have potential for the development of next-generation NIs targeting HAO in the future.

Spatial distribution of ammonia-oxidizing archaea and bacteria across eight freshwater lakes in sediments from Jiangsu of China

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Xu Sun

2014-03-01

Full Text Available Ammonia-oxidizingarchaea (AOA and ammonia-oxidizing bacteria (AOB play an important role innitrogen transformation in freshwater sediments. However, it is still unclear towhat extent the distribution patterns of these microorganisms are affected bythe freshwater sediment across a large geographical scale. This study wasdesigned to gain insight into the heterogeneity distribution of AOA and AOB in32 freshwater sediments from a wide range of ecologic types. Real-time quantitative polymerasechain reaction PCR(qPCR combined with the terminal restrictionfragment length polymorphism(T-RFLP were employed to characterize the abundance, diversity, and communitystructure of the AOA and AOB in 32 freshwater sediments. AOA and AOB wereubiquitous in all sediments, and archaeal amoA far outnumbered bacterial amoA inmost sediments with lower organic matters. The abundance of AOA and AOB did notvary with the freshwater ecological type (macrophyte dominated region and algaedominated region. Based on  the T-RFLP of an amoA gene, this research found that organicmatters in pore water rather than other factors affect the AOA communitystructure in sediments, while the AOB were not significantly different in thefreshwater sediments. Phylogenetic analysis showed that all archaeal amoAsequences fell within either the Crenarchaeotal Group (CG I.1b or the CGI.1asubgroup, and all AOB clustered with genus Nitrosomonas or Nitrosospira. The data obtained inthis study elucidates the role of ammonia-oxidizing archaea andammonia-oxidizing bacteria in the nitrogen cycle of freshwater ecosystems.

Ammonia-oxidizing Bacteria and Archaea in the Rhizosphere of Freshwater Macrophytes

DEFF Research Database (Denmark)

Herrmann, Martina; Schramm, Andreas

2007-01-01

AMMONIA-OXIDIZING ARCHAEA AND BACTERIA IN THE RHIZOSPHERE OF FRESHWATER MACROPHYTES Martina Herrmann and Andreas Schramm Department of Biological Sciences, Microbiology, University of Aarhus, Denmark Aquatic macrophytes such as Littorella uniflora and Lobelia dortmanna release oxygen from...... their roots and thereby stimulate nitrification and coupled nitrification-denitrification in their rhizosphere. However, oxygen release and inorganic nitrogen concentrations differ markedly between macrophyte species. We therefore propose (i) that the rhizosphere of freshwater macrophytes harbours a species......-specific microbial community distinct from that of unvegetated sediment and (ii) that aquatic macrophytes have an impact on abundance and activity of nitrifying and denitrifying bacteria in freshwater sediment. The goal of this study was to test these hypotheses for the key functional group for coupled nitrification...

Transcriptional Response of the Archaeal Ammonia Oxidizer Nitrosopumilus maritimus to Low and Environmentally Relevant Ammonia Concentrations

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Stahl, David A.

2013-01-01

The ability of chemoautotrophic ammonia-oxidizing archaea to compete for ammonia among marine microorganisms at low ambient concentrations has been in part attributed to their extremely high affinity for ammonia, but as yet there is no mechanistic understanding of supporting metabolism. We examined transcription of selected genes for anabolic functions (CO2 fixation, ammonia transport, and cell wall synthesis) and a central catabolic function (ammonia oxidation) in the thaumarchaeon Nitrosopumilus maritimus SCM1 growing at two ammonia concentrations, as measured by combined ammonia and ammonium, one well above the Km for ammonia oxidation (∼500 μM) and the other well below the Km (ammonia-replete to ammonia-limiting conditions. Transcript levels for ammonia oxidation, CO2 fixation, and one of the ammonia transport genes were approximately the same at high and low ammonia availability. Transcripts for all analyzed genes decreased with time in the complete absence of ammonia, but with various rates of decay. The new steady-state mRNA levels established are presumably more reflective of the natural physiological state of ammonia-oxidizing archaea and offer a reference for interpreting message abundance patterns in the natural environment. PMID:23995944

Environmental factors determining ammonia-oxidizing organism distribution and diversity in marine environments.

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Bouskill, Nicholas J; Eveillard, Damien; Chien, Diana; Jayakumar, Amal; Ward, Bess B

2012-03-01

Ammonia-oxidizing bacteria (AOB) and archaea (AOA) play a vital role in bridging the input of fixed nitrogen, through N-fixation and remineralization, to its loss by denitrification and anammox. Yet the major environmental factors determining AOB and AOA population dynamics are little understood, despite both groups having a wide environmental distribution. This study examined the relative abundance of both groups of ammonia-oxidizing organisms (AOO) and the diversity of AOA across large-scale gradients in temperature, salinity and substrate concentration and dissolved oxygen. The relative abundance of AOB and AOA varied across environments, with AOB dominating in the freshwater region of the Chesapeake Bay and AOA more abundant in the water column of the coastal and open ocean. The highest abundance of the AOA amoA gene was recorded in the oxygen minimum zones (OMZs) of the Eastern Tropical South Pacific (ETSP) and the Arabian Sea (AS). The ratio of AOA : AOB varied from 0.7 in the Chesapeake Bay to 1600 in the Sargasso Sea. Relative abundance of both groups strongly correlated with ammonium concentrations. AOA diversity, as determined by phylogenetic analysis of clone library sequences and archetype analysis from a functional gene DNA microarray, detected broad phylogenetic differences across the study sites. However, phylogenetic diversity within physicochemically congruent stations was more similar than would be expected by chance. This suggests that the prevailing geochemistry, rather than localized dispersal, is the major driving factor determining OTU distribution. © 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.

Cultivation and genomic analysis of Candidatus Nitrosocaldus islandicus, a novel obligately thermophilic ammonia-oxidizing Thaumarchaeon

OpenAIRE

De La Torre, Jose; Kirkegaard, Rasmus; Daebeler, Anne; Sedlacek, Christopher; Wagner, Michael; Daims, Holger; Pjevac, Petra; Albersten, Mads; Vierheilig, Julia; Herbold, Craig

2017-01-01

Ammonia-oxidizing archaea (AOA) within the phylum Thaumarchaea are the only known aerobic ammonia oxidizers in geothermal environments. Although molecular data indicate the presence of phylogenetically diverse AOA from the Nitrosocaldus clade, group 1.1b and group 1.1a Thaumarchaea in terrestrial high-temperature habitats, only one enrichment culture of an AOA thriving above 50 C has been reported and functionally analyzed. In this study, we physiologically and genomically characterized a nov...

Bacteria dominate ammonia oxidation in soils used for outdoor cattle overwintering

Czech Academy of Sciences Publication Activity Database

Radl, V.; Chroňáková, Alica; Čuhel, Jiří; Šimek, Miloslav; Elhottová, Dana; Welzl, G.; Schloter, M.

2014-01-01

Roč. 77, May (2014), s. 68-71 ISSN 0929-1393 R&D Projects: GA MŠk LC06066 Grant - others:Akademie věd ČR(CZ) D-CZ 45:05/06 Institutional support: RVO:60077344 Keywords : ammonia oxidation * bacteria * archaea * amoA diversity * urea * pasture Subject RIV: EH - Ecology, Behaviour Impact factor: 2.644, year: 2014

Transcriptional Response of the Archaeal Ammonia Oxidizer Nitrosopumilus maritimus to Low and Environmentally Relevant Ammonia Concentrations

OpenAIRE

Nakagawa, Tatsunori; Stahl, David A.

2013-01-01

The ability of chemoautotrophic ammonia-oxidizing archaea to compete for ammonia among marine microorganisms at low ambient concentrations has been in part attributed to their extremely high affinity for ammonia, but as yet there is no mechanistic understanding of supporting metabolism. We examined transcription of selected genes for anabolic functions (CO2 fixation, ammonia transport, and cell wall synthesis) and a central catabolic function (ammonia oxidation) in the thaumarchaeon Nitrosopu...

Nitrification of archaeal ammonia oxidizers in a high- temperature hot spring

Science.gov (United States)

Chen, Shun; Peng, Xiaotong; Xu, Hengchao; Ta, Kaiwen

2016-04-01

The oxidation of ammonia by microbes has been shown to occur in diverse natural environments. However, the link of in situ nitrification activity to taxonomic identities of ammonia oxidizers in high-temperature environments remains poorly understood. Here, we studied in situ ammonia oxidation rates and the diversity of ammonia-oxidizing Archaea (AOA) in surface and bottom sediments at 77 °C in the Gongxiaoshe hot spring, Tengchong, Yunnan, China. The in situ ammonia oxidation rates measured by the 15N-NO3- pool dilution technique in the surface and bottom sediments were 4.80 and 5.30 nmol N g-1 h-1, respectively. Real-time quantitative polymerase chain reaction (qPCR) indicated that the archaeal 16S rRNA genes and amoA genes were present in the range of 0.128 to 1.96 × 108 and 2.75 to 9.80 × 105 gene copies g-1 sediment, respectively, while bacterial amoA was not detected. Phylogenetic analysis of 16S rRNA genes showed high sequence similarity to thermophilic Candidatus Nitrosocaldus yellowstonii, which represented the most abundant operational taxonomic units (OTU) in both surface and bottom sediments. The archaeal predominance was further supported by fluorescence in situ hybridization (FISH) visualization. The cell-specific rate of ammonia oxidation was estimated to range from 0.410 to 0.790 fmol N archaeal cell-1 h-1, higher than those in the two US Great Basin hot springs. These results suggest the importance of archaeal rather than bacterial ammonia oxidation in driving the nitrogen cycle in terrestrial geothermal environments.

Diversity, abundance and niche differentiation of ammonia-oxidizing prokaryotes in mud deposits of the eastern China marginal seas

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Shaolan eYu

2016-02-01

Full Text Available The eastern China marginal seas are prominent examples of river-dominated ocean margins, whose most characteristic feature is the existence of isolated mud patches on sandy sediments. Ammonia-oxidizing prokaryotes play a crucial role in the nitrogen cycles of many marine environments, including marginal seas. However, few studies have attempted to address the distribution patterns of ammonia-oxidizing prokaryotes in mud deposits of these seas. The horizontal and vertical community composition and abundance of ammonia-oxidizing archaea (AOA and bacteria (AOB were investigated in mud deposits of the South Yellow Sea (SYS and the East China Sea (ECS by using amoA clone libraries and quantitative PCR. The diversity of AOB was comparable or higher in the mud zone of SYS and lower in ECS when compared with AOA. Vertically, surface sediments had generally higher diversity of AOA and AOB than middle and bottom layers. Diversity of AOA and AOB showed significant correlation with latitude. Nitrosopumilus and Nitrosospira lineages dominated AOA and AOB communities, respectively. Both AOA and AOB assemblages exhibited greater variations across different sites than those among various depths at one site. The abundance of bacterial amoA was generally higher than that of archaeal amoA, and both of them decreased with depth. Niche differentiation, which was affected by dissolved oxygen, salinity, ammonia and silicate (SiO32-, was observed between AOA and AOB and among different groups of them. The spatial distribution of AOA and AOB was significantly correlated with δ15NTN and SiO32-, and nitrate and δ13C, respectively. Both archaeal and bacterial amoA abundance correlated strongly with SiO32-. This study improves our understanding of spatial distribution of AOA and AOB in ecosystems featuring oceanic mud deposits.

Diversity, Abundance, and Niche Differentiation of Ammonia-Oxidizing Prokaryotes in Mud Deposits of the Eastern China Marginal Seas.

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Yu, Shaolan; Yao, Peng; Liu, Jiwen; Zhao, Bin; Zhang, Guiling; Zhao, Meixun; Yu, Zhigang; Zhang, Xiao-Hua

2016-01-01

The eastern China marginal seas (ECMS) are prominent examples of river-dominated ocean margins, whose most characteristic feature is the existence of isolated mud patches on sandy sediments. Ammonia-oxidizing prokaryotes play a crucial role in the nitrogen cycles of many marine environments, including marginal seas. However, few studies have attempted to address the distribution patterns of ammonia-oxidizing prokaryotes in mud deposits of these seas. The horizontal and vertical community composition and abundance of ammonia-oxidizing archaea (AOA) and bacteria (AOB) were investigated in mud deposits of the South Yellow Sea (SYS) and the East China Sea (ECS) by using amoA clone libraries and quantitative PCR. The diversity of AOB was comparable or higher in the mud zone of SYS and lower in ECS when compared with AOA. Vertically, surface sediments had generally higher diversity of AOA and AOB than middle and bottom layers. Diversity of AOA and AOB showed significant correlation with latitude. Nitrosopumilus and Nitrosospira lineages dominated AOA and AOB communities, respectively. Both AOA and AOB assemblages exhibited greater variations across different sites than those among various depths at one site. The abundance of bacterial amoA was generally higher than that of archaeal amoA, and both of them decreased with depth. Niche differentiation, which was affected by dissolved oxygen, salinity, ammonia, and silicate (SiO[Formula: see text]), was observed between AOA and AOB and among different groups of them. The spatial distribution of AOA and AOB was significantly correlated with δ(15)NTN and SiO[Formula: see text], and nitrate and δ(13)C, respectively. Both archaeal and bacterial amoA abundance correlated strongly with SiO[Formula: see text]. This study improves our understanding of spatial distribution of AOA and AOB in ecosystems featuring oceanic mud deposits.

The history of aerobic ammonia oxidizers: from the first discoveries to today.

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Monteiro, Maria; Séneca, Joana; Magalhães, Catarina

2014-07-01

Nitrification, the oxidation of ammonia to nitrite and nitrate, has long been considered a central biological process in the global nitrogen cycle, with its first description dated 133 years ago. Until 2005, bacteria were considered the only organisms capable of nitrification. However, the recent discovery of a chemoautotrophic ammonia-oxidizing archaeon, Nitrosopumilus maritimus, changed our concept of the range of organisms involved in nitrification, highlighting the importance of ammonia-oxidizing archaea (AOA) as potential players in global biogeochemical nitrogen transformations. The uniqueness of these archaea justified the creation of a novel archaeal phylum, Thaumarchaeota. These recent discoveries increased the global scientific interest within the microbial ecology society and have triggered an analysis of the importance of bacterial vs archaeal ammonia oxidation in a wide range of natural ecosystems. In this mini review we provide a chronological perspective of the current knowledge on the ammonia oxidation pathway of nitrification, based on the main physiological, ecological and genomic discoveries.

Community structure analysis of soil ammonia oxidizers during vegetation restoration in southwest China.

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Liang, Yueming; He, Xunyang; Liang, Shichu; Zhang, Wei; Chen, Xiangbi; Feng, Shuzheng; Su, Yirong

2014-03-01

Soil ammonia oxidizers play a critical role in nitrogen cycling and ecological restoration. The composition and structure of soil ammonia oxidizers and their impacting factors were studied in four typical ecosystem soils, tussock (T), shrub (S), secondary forest (SF), and primary forest (PF), during vegetation restoration in the Karst region of Southwest China. The composition and structure of the ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) communities were characterized by sequencing the amoA and arch-amoA genes, respectively. The diversity of soil ammonia oxidizers (except in S) and plant Shannon diversity index gradually increased with vegetation restoration, and the ammonia oxidizer communities differed significantly (p soils. AOB Nitrosospira cluster 3b only appeared in PF and SF soils, while Nitrosospira cluster 3a species were found in all soils. Changes in AOB paralleled the changes in soil ammonium content that occurred with vegetation restoration. Redundancy analysis showed that the distribution of dominant AOB species was linked to pH, soil urease activity, and soil C/N ratio, whereas the distribution of dominant AOA species was mainly influenced by litter nitrogen content and C/N ratio. These results suggested that the composition and structure of the AOB community were more sensitive to changes in vegetation and soil ammonium content, and may be an important indicator of nitrogen availability in Karst ecosystem soils. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Response of ammonia oxidizing archaea and bacteria to decabromodiphenyl ether and copper contamination in river sediments.

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Wang, Linqiong; Li, Yi; Niu, Lihua; Zhang, Wenlong; Zhang, Huanjun; Wang, Longfei; Wang, Peifang

2018-01-01

Ammonia oxidation plays a fundamental role in river nitrogen cycling ecosystems, which is normally governed by both ammonia oxidizing archaea (AOA) and ammonia oxidizing bacteria (AOB). Co-contamination of typical emerging pollutant Polybrominated diphenyl ethers (PBDEs) and heavy metal on AOA and AOB communities in river sediments remains unknown. In this study, multiple analytical tools, including high-throughput pyrosequencing and real-time quantitative PCR (qPCR), were used to reveal the ammonia monooxygenase (AMO) activity, subunit alpha (amoA) gene abundance, and community structures of AOA and AOB in river sediments. It was found that the inhibition of AMO activities was increased with the increase of decabromodiphenyl ether (BDE 209, 1-100 mg kg -1 ) and copper (Cu, 50-500 mg kg -1 ) concentrations. Moreover, the synergic effects of BDE 209 and Cu resulted in a higher AMO activity reduction than the individual pollutant BDE 209. The AOA amoA copy number declined by 75.9% and 83.2% and AOB amoA gene abundance declined 82.8% and 90.0% at 20 and 100 mg kg -1 BDE 209 with a 100 mg kg -1 Cu co-contamination, respectively. The pyrosequencing results showed that both AOB and AOA community structures were altered, with a higher change of AOB than that of AOA. The results demonstrated that the AOB microbial community may be better adapted to BDE 209 and Cu pollution, while AOA might possess a greater capacity for stress resistance. Our study provides a better understanding of the ecotoxicological effects of heavy metal and micropollutant combined exposure on AOA and AOB in river sediments. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ammonia-oxidizing bacteria and archaea in wastewater treatment plant sludge and nearby coastal sediment in an industrial area in China.

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Zhang, Yan; Chen, Lujun; Sun, Renhua; Dai, Tianjiao; Tian, Jinping; Wen, Donghui

2015-05-01

Under the increasing pressure of human activities, Hangzhou Bay has become one of the most seriously polluted waters along China's coast. Considering the excessive inorganic nitrogen detected in the bay, in this study, the impact of an effluent from a coastal industrial park on ammonia-oxidizing microorganisms (AOMs) of the receiving area was interpreted for the first time by molecular technologies. Revealed by real-time PCR, the ratio of archaeal amoA/bacterial amoA ranged from 5.68 × 10(-6) to 4.79 × 10(-5) in the activated sludge from two wastewater treatment plants (WWTPs) and 0.54-3.44 in the sediments from the effluent receiving coastal area. Analyzed by clone and pyrosequencing libraries, genus Nitrosomonas was the predominant ammonia-oxidizing bacteria (AOB), but no ammonia-oxidizing archaea (AOA) was abundant enough for sequencing in the activated sludge from the WWTPs; genus Nitrosomonas and Nitrosopumilus were the dominant AOB and AOA, respectively, in the coastal sediments. The different abundance of AOA but similar structure of AOB between the WWTPs and nearby coastal area probably indicated an anthropogenic impact on the microbial ecology in Hangzhou Bay.

amoA Gene abundances and nitrification potential rates suggest that benthic ammonia-oxidizing bacteria and not Archaea dominate N cycling in the Colne Estuary, United Kingdom.

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Li, Jialin; Nedwell, David B; Beddow, Jessica; Dumbrell, Alex J; McKew, Boyd A; Thorpe, Emma L; Whitby, Corinne

2015-01-01

Nitrification, mediated by ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA), is important in global nitrogen cycling. In estuaries where gradients of salinity and ammonia concentrations occur, there may be differential selections for ammonia-oxidizer populations. The aim of this study was to examine the activity, abundance, and diversity of AOA and AOB in surface oxic sediments of a highly nutrified estuary that exhibits gradients of salinity and ammonium. AOB and AOA communities were investigated by measuring ammonia monooxygenase (amoA) gene abundance and nitrification potentials both spatially and temporally. Nitrification potentials differed along the estuary and over time, with the greatest nitrification potentials occurring mid-estuary (8.2 μmol N grams dry weight [gdw](-1) day(-1) in June, increasing to 37.4 μmol N gdw(-1) day(-1) in January). At the estuary head, the nitrification potential was 4.3 μmol N gdw(-1) day(-1) in June, increasing to 11.7 μmol N gdw(-1) day(-1) in January. At the estuary head and mouth, nitrification potentials fluctuated throughout the year. AOB amoA gene abundances were significantly greater (by 100-fold) than those of AOA both spatially and temporally. Nitrosomonas spp. were detected along the estuary by denaturing gradient gel electrophoresis (DGGE) band sequence analysis. In conclusion, AOB dominated over AOA in the estuarine sediments, with the ratio of AOB/AOA amoA gene abundance increasing from the upper (freshwater) to lower (marine) regions of the Colne estuary. These findings suggest that in this nutrified estuary, AOB (possibly Nitrosomonas spp.) were of major significance in nitrification. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Ammonia oxidation kinetics and temperature sensitivity of a natural marine community dominated by Archaea

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Horak, Rachel E A; Qin, Wei; Schauer, Andy J; Armbrust, E Virginia; Ingalls, Anitra E; Moffett, James W; Stahl, David A; Devol, Allan H

2013-01-01

Archaeal ammonia oxidizers (AOAs) are increasingly recognized as prominent members of natural microbial assemblages. Evidence that links the presence of AOA with in situ ammonia oxidation activity is limited, and the abiotic factors that regulate the distribution of AOA natural assemblages are not well defined. We used quantitative PCR to enumerate amoA (encodes α-subunit of ammonia monooxygenase) abundances; AOA amoA gene copies greatly outnumbered ammonia-oxidizing bacteria and amoA transcripts were derived primarily from AOA throughout the water column of Hood Canal, Puget Sound, WA, USA. We generated a Michaelis–Menten kinetics curve for ammonia oxidation by the natural community and found that the measured Km of 98±14 nmol l−1 was close to that for cultivated AOA representative Nitrosopumilus maritimus SCM1. Temperature did not have a significant effect on ammonia oxidation rates for incubation temperatures ranging from 8 to 20 °C, which is within the temperature range for depths of measurable ammonia oxidation at the site. This study provides substantial evidence, through both amoA gene copies and transcript abundances and the kinetics response, that AOA are the dominant active ammonia oxidizers in this marine environment. We propose that future ammonia oxidation experiments use a Km for the natural community to better constrain ammonia oxidation rates determined with the commonly used 15NH4+ dilution technique. PMID:23657360

Bacteria, not archaea, restore nitrification in a zinc-contaminated soil

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Mertens, J.; Broos, K.; Wakelin, S.A.; Kowalchuk, G.A.; Springael, D.; Smolders, E.

2009-01-01

Biological ammonia oxidation had long been thought to be mediated solely by discrete clades of - and -proteobacteria (ammonia-oxidizing bacteria; AOB). However, ammonia-oxidizing Crenarchaeota (ammonia-oxidizing archaea; AOA) have recently been identified and proposed to be the dominant agents of

Bacteria, not archaea, restore nitrification in a zinc contaminated soil.

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Mertens, J.; Broos, K.; Wakelin, S.A.; Kowalchuk, G.A.; Springael, D.; Smolders, E.

2009-01-01

Biological ammonia oxidation had long been thought to be mediated solely by discrete clades of Β- and γ-proteobacteria (ammonia-oxidizing bacteria; AOB). However, ammonia-oxidizing Crenarchaeota (ammonia-oxidizing archaea; AOA) have recently been identified and proposed to be the dominant agents of

Nitrogen and Oxygen Isotope Effects of Ammonia Oxidation by Thermophilic Thaumarchaeota from a Geothermal Water Stream.

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Nishizawa, Manabu; Sakai, Sanae; Konno, Uta; Nakahara, Nozomi; Takaki, Yoshihiro; Saito, Yumi; Imachi, Hiroyuki; Tasumi, Eiji; Makabe, Akiko; Koba, Keisuke; Takai, Ken

2016-08-01

Ammonia oxidation regulates the balance of reduced and oxidized nitrogen pools in nature. Although ammonia-oxidizing archaea have been recently recognized to often outnumber ammonia-oxidizing bacteria in various environments, the contribution of ammonia-oxidizing archaea is still uncertain due to difficulties in the in situ quantification of ammonia oxidation activity. Nitrogen and oxygen isotope ratios of nitrite (δ(15)NNO2- and δ(18)ONO2-, respectively) are geochemical tracers for evaluating the sources and the in situ rate of nitrite turnover determined from the activities of nitrification and denitrification; however, the isotope ratios of nitrite from archaeal ammonia oxidation have been characterized only for a few marine species. We first report the isotope effects of ammonia oxidation at 70°C by thermophilic Thaumarchaeota populations composed almost entirely of "Candidatus Nitrosocaldus." The nitrogen isotope effect of ammonia oxidation varied with ambient pH (25‰ to 32‰) and strongly suggests the oxidation of ammonia, not ammonium. The δ(18)O value of nitrite produced from ammonia oxidation varied with the δ(18)O value of water in the medium but was lower than the isotopic equilibrium value in water. Because experiments have shown that the half-life of abiotic oxygen isotope exchange between nitrite and water is longer than 33 h at 70°C and pH ≥6.6, the rate of ammonia oxidation by thermophilic Thaumarchaeota could be estimated using δ(18)ONO2- in geothermal environments, where the biological nitrite turnover is likely faster than 33 h. This study extended the range of application of nitrite isotopes as a geochemical clock of the ammonia oxidation activity to high-temperature environments. Because ammonia oxidation is generally the rate-limiting step in nitrification that regulates the balance of reduced and oxidized nitrogen pools in nature, it is important to understand the biological and environmental factors underlying the regulation of

The Bacterial Communities of Full-Scale Biologically Active, Granular Activated Carbon Filters Are Stable and Diverse and Potentially Contain Novel Ammonia-Oxidizing Microorganisms

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Hope Wilkinson, Katheryn; Strait, Jacqueline M.; Hozalski, Raymond M.; Sadowksy, Michael J.; Hamilton, Matthew J.

2015-01-01

The bacterial community composition of the full-scale biologically active, granular activated carbon (BAC) filters operated at the St. Paul Regional Water Services (SPRWS) was investigated using Illumina MiSeq analysis of PCR-amplified 16S rRNA gene fragments. These bacterial communities were consistently diverse (Shannon index, >4.4; richness estimates, >1,500 unique operational taxonomic units [OTUs]) throughout the duration of the 12-month study period. In addition, only modest shifts in the quantities of individual bacterial populations were observed; of the 15 most prominent OTUs, the most highly variable population (a Variovorax sp.) modulated less than 13-fold over time and less than 8-fold from filter to filter. The most prominent population in the profiles was a Nitrospira sp., representing 13 to 21% of the community. Interestingly, very few of the known ammonia-oxidizing bacteria (AOB; <0.07%) and no ammonia-oxidizing Archaea were detected in the profiles. Quantitative PCR of amoA genes, however, suggested that AOB were prominent in the bacterial communities (amoA/16S rRNA gene ratio, 1 to 10%). We conclude, therefore, that the BAC filters at the SPRWS potentially contained significant numbers of unidentified and novel ammonia-oxidizing microorganisms that possess amoA genes similar to those of previously described AOB. PMID:26209671

Reverse-transcriptional gene expression of anammox and ammonia-oxidizing archaea and bacteria in soybean and rice paddy soils of Northeast China.

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Wang, Jing; Dong, Hailiang; Wang, Weidong; Gu, Ji-Dong

2014-03-01

The relative gene expression of hydrazine oxidoreductase encoding gene (hzo) for anaerobic ammonium oxidizing bacteria (anammox) and ammonia monooxygenase encoding gene (amoA) for both ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) in Sanjiang Plain soybean and rice paddy soils of Northeast China was investigated by using real-time reverse-transcriptional quantitative PCR. Metabolically active populations of anammox, AOA, and AOB in rice paddy soils were evident by the presence and successful quantification of hzo mRNA and amoA mRNA genes. The expression ratio of amoA gene for both AOA and AOB varied between soybean soils and different rice paddy soils while the expression of hzo gene for anammox was detectable only in rice paddy soils by showing a diverse relative expression ratio in each soil sample. Gene expression of both archaeal and bacterial amoA genes in rice paddy soils differed among the three sampling depths, but that of hzo was not. Both archaeal and bacterial amoA genes showed an increase trend of expression level with continuation of rice paddy cultivation, but the low expression ratio of hzo gene indicated a relatively small contribution of anammox in overall removal of inorganic nitrogen through N2 even under anoxic and high nitrogen input in agriculture. Bacterial amoA gene from two soybean fields and three rice paddy fields were also analyzed for community composition by denaturing gradient gel electrophoresis fingerprint. Community shift was observed between soybean and paddy fields and within each of them. The consistent occurrence of three bands 5, 6, and 7 in all samples showed their high adaptability for both arid cultivation and continuous rice paddy cultivation. Our data suggest that AOA and AOB are playing a more important role in nitrogen transformation in agricultural soils in oxic or anoxic environment and anammox bacteria may also contribute but in a less extent to N transformation in these agricultural soils

Benthic Ammonia Oxidizers Differ in Community Structure and Biogeochemical Potential Across a Riverine Delta

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Julian eDamashek

2015-01-01

Full Text Available Nitrogen pollution in coastal zones is a widespread issue, particularly in ecosystems with urban or agricultural watersheds. California’s Sacramento-San Joaquin Delta, at the landward reaches of San Francisco Bay, is highly impacted by both agricultural runoff and sewage effluent, leading to chronically high nutrient loadings. In particular, the massive discharge of ammonium into the Sacramento River has altered this ecosystem by increasing ammonium concentrations and thus changing the stoichiometry of inorganic nitrogen stocks, with potential effects throughout the food web. To date, however, there has been little research examining N biogeochemistry or N-cycling microbial communities in this system. We report the first data on benthic ammonia-oxidizing microbial communities and potential nitrification rates for the Sacramento-San Joaquin Delta, focusing on the functional gene amoA (encoding the α-subunit of ammonia monooxygenase. There were stark regional differences in ammonia-oxidizing communities, with ammonia-oxidizing bacteria (AOB outnumbering ammonia-oxidizing archaea (AOA only in the ammonium-rich Sacramento River. High potential nitrification rates in the Sacramento River suggested these communities may be capable of oxidizing significant amounts of ammonium, compared to the San Joaquin River and the upper reaches of San Francisco Bay. Gene diversity also showed regional patterns, as well as phylogenetically unique ammonia oxidizers in the Sacramento River. The community structure and biogeochemical function of benthic ammonia oxidizers appears related to nutrient loadings. Unraveling the microbial ecology and biogeochemistry of N cycling pathways is a critical step toward understanding how such ecosystems respond to the changing environmental conditions wrought by human development and climate change.

Ammonia and nitrite oxidation in the Eastern Tropical North Pacific

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Peng, Xuefeng; Fuchsman, Clara A.; Jayakumar, Amal; Oleynik, Sergey; Martens-Habbena, Willm; Devol, Allan H.; Ward, Bess B.

2015-12-01

Nitrification plays a key role in the marine nitrogen (N) cycle, including in oceanic oxygen minimum zones (OMZs), which are hot spots for denitrification and anaerobic ammonia oxidation (anammox). Recent evidence suggests that nitrification links the source (remineralized organic matter) and sink (denitrification and anammox) of fixed N directly in the steep oxycline in the OMZs. We performed shipboard incubations with 15N tracers to characterize the depth distribution of nitrification in the Eastern Tropical North Pacific (ETNP). Additional experiments were conducted to investigate photoinhibition. Allylthiourea (ATU) was used to distinguish the contribution of archaeal and bacterial ammonia oxidation. The abundance of archaeal and β-proteobacterial ammonia monooxygenase gene subunit A (amoA) was determined by quantitative polymerase chain reaction. The rates of ammonia and nitrite oxidation showed distinct subsurface maxima, with the latter slightly deeper than the former. The ammonia oxidation maximum coincided with the primary nitrite concentration maximum, archaeal amoA gene maximum, and the subsurface nitrous oxide maximum. Negligible rates of ammonia oxidation were found at anoxic depths, where high rates of nitrite oxidation were measured. Archaeal amoA gene abundance was generally 1 to 2 orders of magnitude higher than bacterial amoA gene abundance, and inhibition of ammonia-oxidizing bacteria with 10 μM ATU did not affect ammonia oxidation rates, indicating the dominance of archaea in ammonia oxidation. These results depict highly dynamic activities of ammonia and nitrite oxidation in the oxycline of the ETNP OMZ.

High abundances of potentially active ammonia-oxidizing bacteria and archaea in oligotrophic, high-altitude lakes of the Sierra Nevada, California, USA.

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Curtis J Hayden

Full Text Available Nitrification plays a central role in the nitrogen cycle by determining the oxidation state of nitrogen and its subsequent bioavailability and cycling. However, relatively little is known about the underlying ecology of the microbial communities that carry out nitrification in freshwater ecosystems--and particularly within high-altitude oligotrophic lakes, where nitrogen is frequently a limiting nutrient. We quantified ammonia-oxidizing archaea (AOA and bacteria (AOB in 9 high-altitude lakes (2289-3160 m in the Sierra Nevada, California, USA, in relation to spatial and biogeochemical data. Based on their ammonia monooxygenase (amoA genes, AOB and AOA were frequently detected. AOB were present in 88% of samples and were more abundant than AOA in all samples. Both groups showed >100 fold variation in abundance between different lakes, and were also variable through time within individual lakes. Nutrient concentrations (ammonium, nitrite, nitrate, and phosphate were generally low but also varied across and within lakes, suggestive of active internal nutrient cycling; AOB abundance was significantly correlated with phosphate (r(2 = 0.32, p<0.1, whereas AOA abundance was inversely correlated with lake elevation (r(2 = 0.43, p<0.05. We also measured low rates of ammonia oxidation--indicating that AOB, AOA, or both, may be biogeochemically active in these oligotrophic ecosystems. Our data indicate that dynamic populations of AOB and AOA are found in oligotrophic, high-altitude, freshwater lakes.

Integrated structural biology and molecular ecology of N-cycling enzymes from ammonia-oxidizing archaea.

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Tolar, Bradley B; Herrmann, Jonathan; Bargar, John R; van den Bedem, Henry; Wakatsuki, Soichi; Francis, Christopher A

2017-10-01

Knowledge of the molecular ecology and environmental determinants of ammonia-oxidizing organisms is critical to understanding and predicting the global nitrogen (N) and carbon cycles, but an incomplete biochemical picture hinders in vitro studies of N-cycling enzymes. Although an integrative structural and dynamic characterization at the atomic scale would advance our understanding of function tremendously, structural knowledge of key N-cycling enzymes from ecologically relevant ammonia oxidizers is unfortunately extremely limited. Here, we discuss the challenges and opportunities for examining the ecology of ammonia-oxidizing organisms, particularly uncultivated Thaumarchaeota, through (meta)genome-driven structural biology of the enzymes ammonia monooxygenase (AMO) and nitrite reductase (NirK). © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

Enrichment and Characterization of an Autotrophic Ammonia-Oxidizing Archaeon of Mesophilic Crenarchaeal Group I.1a from an Agricultural Soil

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Jung, M.Y.; Park, S.J.; Min, D.; Kim, J.S.; Rijpstra, W.I.C.; Sinninghe Damsté, J.S.; Kim, G.J.; Madsen, E.L.; Rhee, S.K.

2011-01-01

Soil nitrification is an important process for agricultural productivity and environmental pollution. Though one cultivated representative of ammonia-oxidizing Archaea from soil has been described, additional representatives warrant characterization. We describe an ammonia-oxidizing archaeon (strain

Effects of submerged macrophytes on the abundance and community composition of ammonia-oxidizing prokaryotes in a eutrophic lake.

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Zhao, Da-yong; Luo, Juan; Zeng, Jin; Wang, Meng; Yan, Wen-ming; Huang, Rui; Wu, Qinglong L

2014-01-01

Abundances and community compositions of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) in unvegetated sediment and the rhizosphere sediments of three submerged macrophytes (Ceratophyllum demersum, Vallisneria spinulosa, and Potamogeton crispus) were investigated in a large, eutrophic freshwater lake, Lake Taihu. Abundances of archaeal ammonia monooxygenase alpha-subunit (amoA) gene (from 6.56 × 10(6) copies to 1.06 × 10(7) copies per gram of dry sediment) were higher than those of bacterial amoA (from 6.13 × 10(5) to 3.21 × 10(6) copies per gram of dry sediment) in all samples. Submerged macrophytes exhibited no significant effect on the abundance and diversity of archaeal amoA gene. C. demersum and V. spinulosa increased the abundance and diversity of bacterial amoA gene in their rhizosphere sediment. However, the diversity of bacterial amoA gene in the rhizosphere sediments of P. crispus was decreased. The data obtained in this study would be helpful to elucidate the roles of submerged macrophytes involved in the nitrogen cycling of eutrophic lake ecosystems.

Archaeal dominated ammonia-oxidizing communities in Icelandic grassland soils are moderately affected by long-term N fertilization and geothermal heating

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Daebeler, A.; Abell, G.C.J.; Bodelier, P.L.E.; Bodrossy, L.; Frampton, D.M.; Hefting, M.M.; Laanbroek, H.J.

2012-01-01

The contribution of ammonia-oxidizing bacteria and archaea (AOB and AOA, respectively) to the net oxidation of ammonia varies greatly between terrestrial environments. To better understand, predict and possibly manage terrestrial nitrogen turnover, we need to develop a conceptual understanding of

Ammonia oxidation, denitrification and dissimilatory nitrate reduction to ammonium in two US Great Basin hot springs with abundant ammonia-oxidizing archaea.

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Dodsworth, Jeremy A; Hungate, Bruce A; Hedlund, Brian P

2011-08-01

Many thermophiles catalyse free energy-yielding redox reactions involving nitrogenous compounds; however, little is known about these processes in natural thermal environments. Rates of ammonia oxidation, denitrification and dissimilatory nitrate reduction to ammonium (DNRA) were measured in source water and sediments of two ≈ 80°C springs in the US Great Basin. Ammonia oxidation and denitrification occurred mainly in sediments. Ammonia oxidation rates measured using (15)N-NO(3)(-) pool dilution ranged from 5.5 ± 0.8 to 8.6 ± 0.9 nmol N g(-1) h(-1) and were unaffected or only mildly stimulated by amendment with NH(4) Cl. Denitrification rates measured using acetylene block ranged from 15.8 ± 0.7 to 51 ± 12 nmol N g(-1) h(-1) and were stimulated by amendment with NO(3)(-) and complex organic compounds. The DNRA rate in one spring sediment measured using an (15)N-NO(3)(-) tracer was 315 ± 48 nmol N g(-1) h(-1). Both springs harboured distinct planktonic and sediment microbial communities. Close relatives of the autotrophic, ammonia-oxidizing archaeon 'Candidatus Nitrosocaldus yellowstonii' represented the most abundant OTU in both spring sediments by 16S rRNA gene pyrotag analysis. Quantitative PCR (qPCR) indicated that 'Ca. N. yellowstonii'amoA and 16S rRNA genes were present at 3.5-3.9 × 10(8) and 6.4-9.0 × 10(8) copies g(-1) sediment. Potential denitrifiers included members of the Aquificales and Thermales. Thermus spp. comprised <1% of 16S rRNA gene pyrotags in both sediments and qPCR for T. thermophilus narG revealed sediment populations of 1.3-1.7 × 10(6) copies g(-1) sediment. These data indicate a highly active nitrogen cycle (N-cycle) in these springs and suggest that ammonia oxidation may be a major source of energy fuelling primary production. © 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.

Niche specificity of ammonia-oxidizing archaeal and bacterial communities in a freshwater wetland receiving municipal wastewater in Daqing, Northeast China.

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Lee, Kwok-Ho; Wang, Yong-Feng; Li, Hui; Gu, Ji-Dong

2014-12-01

Ecophysiological differences between ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) enable them to adapt to different niches in complex freshwater wetland ecosystems. The community characters of AOA and AOB in the different niches in a freshwater wetland receiving municipal wastewater, as well as the physicochemical parameters of sediment/soil samples, were investigated in this study. AOA community structures varied and separated from each other among four different niches. Wetland vegetation including aquatic macrophytes and terrestrial plants affected the AOA community composition but less for AOB, whereas sediment depths might contribute to the AOB community shift. The diversity of AOA communities was higher than that of AOB across all four niches. Archaeal and bacterial amoA genes (encoding for the alpha-subunit of ammonia monooxygenases) were most diverse in the dry-land niche, indicating O2 availability might favor ammonia oxidation. The majority of AOA amoA sequences belonged to the Soil/sediment Cluster B in the freshwater wetland ecosystems, while the dominant AOB amoA sequences were affiliated with Nitrosospira-like cluster. In the Nitrosospira-like cluster, AOB amoA gene sequences affiliated with the uncultured ammonia-oxidizing beta-proteobacteria constituted the largest portion (99%). Moreover, independent methods for phylogenetic tree analysis supported high parsimony bootstrap values. As a consequence, it is proposed that Nitrosospira-like amoA gene sequences recovered in this study represent a potentially novel cluster, grouping with the sequences from Gulf of Mexico deposited in the public databases.

Diversity of ammonia-oxidizing bacteria in relation to soil environment in Ebinur Lake Wetland

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Wenge Hu

2016-03-01

Full Text Available Ammonia oxidation is the first and rate-limiting step of nitrification and is carried out by ammonia-oxidizing bacteria (AOB. Ebinur Lake Wetland, the most representative temperate arid zone wetland ecosystem in China, is the centre of oasis and desertification of the northern slope of Tianshan conjugate. Soil samples were collected from three sites (Tamarix ramosissima, Halocnemum strobilaceum and Phragmites australis and different soil layers (0–5, 5–15, 15–25 and 25–35 cm in this wetland in spring, summer and autumn and were used to characterize the diversity of AOB based on the ammonia monooxygenase (amoA gene. Polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE and bivariate correlation analysis were used to analyse the relationship between the diversity of AOB and soil environment factors. The PCR-DGGE indicated that the diversity of AOB was high in the entire sample and the Shannon diversity index varied from 1.369 to 2.471. The phylogenetic analysis showed that the amoA fragments were grouped into Nitrosospira sp. and Nitrosomonas sp. Most amoA gene sequences fell within the Nitrosospira sp. cluster, and only a few sequences were clustered with Nitrosomonas sp., indicating that Nitrosospira sp. may be more adaptable than Nitrosomonas sp. in this area. Bivariate correlation analysis showed that the diversity of AOB was significantly correlated with soil organic matter, conductivity, total phosphorus and nitrate in the Ebinur Lake Wetland in Xinjiang.

Archaeal dominated ammonia-oxidizing communities in Icelandic grassland soils are moderately affected by long-term N fertilization and geothermal heating

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Daebeler, Anne; Abell, Guy C. J.; Bodelier, Paul L. E.; Bodrossy, Levente; Frampton, Dion M. F.; Hefting, Mariet M.; Laanbroek, Hendrikus J.

2012-01-01

The contribution of ammonia-oxidizing bacteria and archaea (AOB and AOA, respectively) to the net oxidation of ammonia varies greatly between terrestrial environments. To better understand, predict and possibly manage terrestrial nitrogen turnover, we need to develop a conceptual understanding of ammonia oxidation as a function of environmental conditions including the ecophysiology of associated organisms. We examined the discrete and combined effects of mineral nitrogen deposition and geothermal heating on ammonia-oxidizing communities by sampling soils from a long-term fertilization site along a temperature gradient in Icelandic grasslands. Microarray, clone library and quantitative PCR analyses of the ammonia monooxygenase subunit A (amoA) gene accompanied by physico-chemical measurements of the soil properties were conducted. In contrast to most other terrestrial environments, the ammonia-oxidizing communities consisted almost exclusively of archaea. Their bacterial counterparts proved to be undetectable by quantitative polymerase chain reaction suggesting AOB are only of minor relevance for ammonia oxidation in these soils. Our results show that fertilization and local, geothermal warming affected detectable ammonia-oxidizing communities, but not soil chemistry: only a subset of the detected AOA phylotypes was present in higher temperature soils and AOA abundance was increased in the fertilized soils, while soil physio-chemical properties remained unchanged. Differences in distribution and structure of AOA communities were best explained by soil pH and clay content irrespective of temperature or fertilizer treatment in these grassland soils, suggesting that these factors have a greater potential for ecological niche-differentiation of AOA in soil than temperature and N fertilization. PMID:23060870

Archaeal dominated ammonia-oxidizing communities in Icelandic grassland soils are moderately affected by long-term N fertilization and geothermal heating

Directory of Open Access Journals (Sweden)

Anne eDaebeler

2012-10-01

Full Text Available The contribution of ammonia-oxidizing bacteria and archaea (AOB and AOA, respectively to the net oxidation of ammonia varies greatly between terrestrial environments. To better understand, predict and possibly manage terrestrial nitrogen turnover, we need to develop a conceptual understanding of ammonia oxidation as a function of environmental conditions including the ecophysiology of the associated organisms. We examined the discrete and combined effects of mineral nitrogen deposition and geothermal heating on ammonia-oxidizing communities by sampling soils from a long-term fertilisation site along a temperature gradient in Icelandic grasslands. Microarray, clone library and quantitative PCR analyses of the ammonia monooxygenase subunit A (amoA gene accompanied by physico-chemical measurements of the soil properties were conducted. In contrast to most other terrestrial environments, the ammonia-oxidizing communities consisted almost exclusively of archaea. Their bacterial counterparts proved to be undetectable by quantitative PCR suggesting AOB are only of minor relevance for ammonia oxidation in these soils. Our results show that fertilization and local, geothermal warming affected detectable ammonia-oxidizing communities, but not soil chemistry: only a subset of the detected AOA phylotypes was present in higher temperature soils and AOA abundance was increased in the fertilized soils, while the measured soil physico-chemical properties remained unchanged. Differences in distribution and structure of AOA communities were best explained by soil pH and clay content irrespective of temperature or fertilizer treatment in these grassland soils, suggesting that these factors have a greater potential for ecological niche-differentiation of AOA in soil than temperature and N fertilization.

Archaeal dominated ammonia-oxidizing communities in Icelandic grassland soils are moderately affected by long-term N fertilization and geothermal heating.

Science.gov (United States)

Daebeler, Anne; Abell, Guy C J; Bodelier, Paul L E; Bodrossy, Levente; Frampton, Dion M F; Hefting, Mariet M; Laanbroek, Hendrikus J

2012-01-01

The contribution of ammonia-oxidizing bacteria and archaea (AOB and AOA, respectively) to the net oxidation of ammonia varies greatly between terrestrial environments. To better understand, predict and possibly manage terrestrial nitrogen turnover, we need to develop a conceptual understanding of ammonia oxidation as a function of environmental conditions including the ecophysiology of associated organisms. We examined the discrete and combined effects of mineral nitrogen deposition and geothermal heating on ammonia-oxidizing communities by sampling soils from a long-term fertilization site along a temperature gradient in Icelandic grasslands. Microarray, clone library and quantitative PCR analyses of the ammonia monooxygenase subunit A (amoA) gene accompanied by physico-chemical measurements of the soil properties were conducted. In contrast to most other terrestrial environments, the ammonia-oxidizing communities consisted almost exclusively of archaea. Their bacterial counterparts proved to be undetectable by quantitative polymerase chain reaction suggesting AOB are only of minor relevance for ammonia oxidation in these soils. Our results show that fertilization and local, geothermal warming affected detectable ammonia-oxidizing communities, but not soil chemistry: only a subset of the detected AOA phylotypes was present in higher temperature soils and AOA abundance was increased in the fertilized soils, while soil physio-chemical properties remained unchanged. Differences in distribution and structure of AOA communities were best explained by soil pH and clay content irrespective of temperature or fertilizer treatment in these grassland soils, suggesting that these factors have a greater potential for ecological niche-differentiation of AOA in soil than temperature and N fertilization.

Land-use systems affect Archaeal community structure and functional diversity in western Amazon soils

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Acácio Aparecido Navarrete

2011-10-01

Full Text Available The study of the ecology of soil microbial communities at relevant spatial scales is primordial in the wide Amazon region due to the current land use changes. In this study, the diversity of the Archaea domain (community structure and ammonia-oxidizing Archaea (richness and community composition were investigated using molecular biology-based techniques in different land-use systems in western Amazonia, Brazil. Soil samples were collected in two periods with high precipitation (March 2008 and January 2009 from Inceptisols under primary tropical rainforest, secondary forest (5-20 year old, agricultural systems of indigenous people and cattle pasture. Denaturing gradient gel electrophoresis of polymerase chain reaction-amplified DNA (PCR-DGGE using the 16S rRNA gene as a biomarker showed that archaeal community structures in crops and pasture soils are different from those in primary forest soil, which is more similar to the community structure in secondary forest soil. Sequence analysis of excised DGGE bands indicated the presence of crenarchaeal and euryarchaeal organisms. Based on clone library analysis of the gene coding the subunit of the enzyme ammonia monooxygenase (amoA of Archaea (306 sequences, the Shannon-Wiener function and Simpson's index showed a greater ammonia-oxidizing archaeal diversity in primary forest soils (H' = 2.1486; D = 0.1366, followed by a lower diversity in soils under pasture (H' = 1.9629; D = 0.1715, crops (H' = 1.4613; D = 0.3309 and secondary forest (H' = 0.8633; D = 0.5405. All cloned inserts were similar to the Crenarchaeota amoA gene clones (identity > 95 % previously found in soils and sediments and distributed primarily in three major phylogenetic clusters. The findings indicate that agricultural systems of indigenous people and cattle pasture affect the archaeal community structure and diversity of ammonia-oxidizing Archaea in western Amazon soils.

Diversity, abundance and distribution of amoA-encoding archaea in deep-sea methane seep sediments of the Okhotsk Sea.

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Dang, Hongyue; Luan, Xi-Wu; Chen, Ruipeng; Zhang, Xiaoxia; Guo, Lizhong; Klotz, Martin G

2010-06-01

The ecological characteristics of amoA-encoding archaea (AEA) in deep-sea sediments are largely unsolved. This paper aimed to study the diversity, structure, distribution and abundance of the archaeal community and especially its AEA components in the cold seep surface sediments of the Okhotsk Sea, a marginal sea harboring one of the largest methane hydrate reservoirs in the world. Diverse archaeal 16S rRNA gene sequences were identified, with the majority being related to sequences from other cold seep and methane-rich sediment environments. However, the AEA diversity and abundance were quite low as revealed by amoA gene analyses. Correlation analysis indicates that the abundance of the archaeal amoA genes was correlated with the sediment organic matter content. Thus, it is possible that the amoA-carrying archaea here might utilize organic matter for a living. The affiliation of certain archaeal amoA sequences to the GenBank sequences originally obtained from deep-sea hydrothermal vent environments indicated that the related AEA either have a wide range of temperature adaptation or they have a thermophilic evolutionary history in the modern cold deep-sea sediments of the Okhotsk Sea. The dominance of ammonia-oxidizing bacteria over AEA may indicate that bacteria play a significant role in nitrification in the Okhotsk Sea cold seep sediments.

Inhibition of bacterial ammonia oxidation by organohydrazines in soil microcosms

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Yucheng eWu

2012-01-01

Full Text Available Hydroxylamine oxidation by hydroxylamine oxidoreductase (HAO is a key step for energy-yielding in support of the growth of ammonia-oxidizing bacteria (AOB. Organohydrazines have been shown to inactivate HAO from Nitrosomonas europaea, and may serve as selective inhibitors to differentiate bacterial from archaeal ammonia oxidation due to the absence of bacterial HAO gene homologue in known ammonia-oxidizing archaea (AOA. In this study, the effects of three organohydrazines on activity, abundance and composition of AOB and AOA were evaluated in soil microcosms. The results indicate that phenylhydrazine and methylhydrazine at the concentration of 100 mol per gram dry weight soil completely suppressed the activity of soil nitrification. DGGE fingerprinting and sequencing analysis of bacterial ammonia monooxygenase subunit A gene (amoA clearly demonstrated that nitrification activity change is well paralleled with the growth of Nitrosomonas europaea-like AOB in soil microcosms. No significant correlation between AOA community structure and nitrification activity was observed among all treatments during the incubation period, although incomplete inhibition of nitrification activity occurred in 2-hydroxyethylhydrazine-amended soil microcosms. These findings show that the HAO-targeted organohydrazines can effectively inhibit bacterial nitrification in soil, and the mechanism of organohydrazine affecting AOA remains unclear.

Insights into high-temperature nitrogen cycling from studies of the thermophilic ammonia-oxidizing archaeon Nitrosocaldus yellowstonii. (Invited)

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de la Torre, J. R.

2010-12-01

Our understanding of the nitrogen cycle has advanced significantly in recent years with the discovery of new metabolic processes and the recognition that key processes such as aerobic ammonia oxidation are more broadly distributed among extant organisms and habitat ranges. Nitrification, the oxidation of ammonia to nitrite and nitrate, is a key component of the nitrogen cycle and, until recently, was thought to be mediated exclusively by the ammonia-oxidizing bacteria (AOB). The discovery that mesophilic marine archaea, some of the most abundant microorganisms on the planet, are capable of oxidizing ammonia to nitrite fundamentally changed our perception of the global nitrogen cycle. Ammonia-oxidizing archaea (AOA) are now thought to be significant drivers of nitrification in many marine and terrestrial environments. Most studies, however, have focused on the contribution of AOA to nitrogen cycling in mesophilic environments. Our recent discovery of a thermophilic AOA, Nitrosocaldus yellowstonii, has expanded the role and habitat range of AOA to include high temperature environments. Numerous studies have shown that AOA are widely distributed in geothermal habitats with a wide range of temperature and pH. The availability of multiple AOA genome sequences, combined with metagenomic studies from mesophilic and thermophilic environments gives us a better understanding of the physiology, ecology and evolution of these organisms. Recent studies have proposed that the AOA represent the most deeply branching lineage within the Archaea, the Thaumarchaeota. Furthermore, genomic comparisons between AOA and AOB reveal significant differences in the proposed pathways for ammonia oxidation. These genetic differences likely explain fundamental physiological differences such as the resistance of N. yellowstonii and other AOA to the classical nitrification inhibitors allylthiourea and acetylene. Physiological studies suggest that the marine AOA are adapted to oligotrophic

Bacterial domination over Archaea in ammonia oxidation in a monsoon-driven tropical estuary

Digital Repository Service at National Institute of Oceanography (India)

Vipindas, P.V.; Anas, A.; Jasmin, C.; Lallu, K.R.; Fausia, K.H.; Balachandran, K.K.; Muraleedharan, K.R.; Nair, S.

Autotrophic ammonia oxidizing microorganisms,which are responsible for the rate-limiting step of nitrification in most aquatic systems, have not been studied in tropical estuaries. Cochin estuary (CE) is one of the largest, productive, and monsoon...

Different Recovery Processes of Soil Ammonia Oxidizers from Flooding Disturbance.

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Ye, Fei; Ma, Mao-Hua; Op den Camp, Huub J M; Chatzinotas, Antonis; Li, Lei; Lv, Ming-Quan; Wu, Sheng-Jun; Wang, Yu

2018-04-11

Understanding how microorganisms respond to environmental disturbance is one of the key focuses in microbial ecology. Ammonia-oxidizing bacteria (AOB) and archaea (AOA) are responsible for ammonia oxidation which is a crucial step in the nitrogen cycle. Although the physiology, distribution, and activity of AOA and AOB in soil have been extensively investigated, their recovery from a natural disturbance remains largely unknown. To assess the recovery capacities, including resistance and resilience, of AOA and AOB, soil samples were taken from a reservoir riparian zone which experienced periodically water flooding. The samples were classified into three groups (flooding, recovery, and control) for a high-throughput sequencing and quantitative PCR analysis. We used a relative quantitative index of both the resistance (RS) and resilience (RL) to assess the variation of gene abundance, alpha-diversity, and community composition. The AOA generally demonstrated a better recovery capability after the flooding disturbance compared to AOB. In particular, AOA were more resilient after the flooding disturbance. Taxa within the AOA and AOB showed different RS and RL values, with the most abundant taxa showing in general the highest RS indices. Soil NH 4 + and Fe 2+ /Fe 3+ were the main variables controlling the key taxa of AOA and AOB and probably influenced the resistance and resilience properties of AOA and AOB communities. The distinct mechanisms of AOA and AOB in maintaining community stability against the flooding disturbance might be linked to the different life-history strategies: the AOA community was more likely to represent r-strategists in contrast to the AOB community following a K-life strategy. Our results indicated that the AOA may play a vital role in ammonia oxidation in a fluctuating habitat and contribute to the stability of riparian ecosystem.

Emergent macrophytes modify the abundance and community composition of ammonia oxidizers in their rhizosphere sediments.

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Zhao, Dayong; He, Xiaowei; Huang, Rui; Yan, Wenming; Yu, Zhongbo

2017-07-01

Ammonia oxidation is a crucial process in global nitrogen cycling, which is catalyzed by the ammonia oxidizers. Emergent plants play important roles in the freshwater ecosystem. Therefore, it is meaningful to investigate the effects of emergent macrophytes on the abundance and community composition of ammonia oxidizers. In the present study, two commonly found emergent macrophytes (Zizania caduciflora and Phragmitas communis) were obtained from freshwater lakes and the abundance and community composition of the ammonia-oxidizing prokaryotes in the rhizosphere sediments of these emergent macrophytes were investigated. The abundance of the bacterial amoA gene was higher in the rhizosphere sediments of the emergent macrophytes than those of bulk sediments. Significant positive correlation was found between the potential nitrification rates (PNRs) and the abundance of bacterial amoA gene, suggesting that ammonia-oxidizing bacteria (AOB) might play an important role in the nitrification process of the rhizosphere sediments of emergent macrophytes. The Nitrosotalea cluster is the dominant ammonia-oxidizing archaea (AOA) group in all the sediment samples. Analysis of AOB group showed that the N. europaeal cluster dominated the rhizosphere sediments of Z. caduciflora and the bulk sediments, whereas the Nitrosospira cluster was the dominant AOB group in the rhizosphere sediments of P. communis. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Cultivation and Genomic Analysis of "Candidatus Nitrosocaldus islandicus," an Obligately Thermophilic, Ammonia-Oxidizing Thaumarchaeon from a Hot Spring Biofilm in Graendalur Valley, Iceland.

Science.gov (United States)

Daebeler, Anne; Herbold, Craig W; Vierheilig, Julia; Sedlacek, Christopher J; Pjevac, Petra; Albertsen, Mads; Kirkegaard, Rasmus H; de la Torre, José R; Daims, Holger; Wagner, Michael

2018-01-01

Ammonia-oxidizing archaea (AOA) within the phylum Thaumarchaeota are the only known aerobic ammonia oxidizers in geothermal environments. Although molecular data indicate the presence of phylogenetically diverse AOA from the Nitrosocaldus clade, group 1.1b and group 1.1a Thaumarchaeota in terrestrial high-temperature habitats, only one enrichment culture of an AOA thriving above 50°C has been reported and functionally analyzed. In this study, we physiologically and genomically characterized a newly discovered thaumarchaeon from the deep-branching Nitrosocaldaceae family of which we have obtained a high (∼85%) enrichment from biofilm of an Icelandic hot spring (73°C). This AOA, which we provisionally refer to as " Candidatus Nitrosocaldus islandicus," is an obligately thermophilic, aerobic chemolithoautotrophic ammonia oxidizer, which stoichiometrically converts ammonia to nitrite at temperatures between 50 and 70°C. " Ca. N. islandicus" encodes the expected repertoire of enzymes proposed to be required for archaeal ammonia oxidation, but unexpectedly lacks a nirK gene and also possesses no identifiable other enzyme for nitric oxide (NO) generation. Nevertheless, ammonia oxidation by this AOA appears to be NO-dependent as " Ca. N. islandicus" is, like all other tested AOA, inhibited by the addition of an NO scavenger. Furthermore, comparative genomics revealed that " Ca. N. islandicus" has the potential for aromatic amino acid fermentation as its genome encodes an indolepyruvate oxidoreductase ( iorAB ) as well as a type 3b hydrogenase, which are not present in any other sequenced AOA. A further surprising genomic feature of this thermophilic ammonia oxidizer is the absence of DNA polymerase D genes - one of the predominant replicative DNA polymerases in all other ammonia-oxidizing Thaumarchaeota. Collectively, our findings suggest that metabolic versatility and DNA replication might differ substantially between obligately thermophilic and other AOA.

Cultivation and Genomic Analysis of “Candidatus Nitrosocaldus islandicus,” an Obligately Thermophilic, Ammonia-Oxidizing Thaumarchaeon from a Hot Spring Biofilm in Graendalur Valley, Iceland

Science.gov (United States)

Daebeler, Anne; Herbold, Craig W.; Vierheilig, Julia; Sedlacek, Christopher J.; Pjevac, Petra; Albertsen, Mads; Kirkegaard, Rasmus H.; de la Torre, José R.; Daims, Holger; Wagner, Michael

2018-01-01

Ammonia-oxidizing archaea (AOA) within the phylum Thaumarchaeota are the only known aerobic ammonia oxidizers in geothermal environments. Although molecular data indicate the presence of phylogenetically diverse AOA from the Nitrosocaldus clade, group 1.1b and group 1.1a Thaumarchaeota in terrestrial high-temperature habitats, only one§ enrichment culture of an AOA thriving above 50°C has been reported and functionally analyzed. In this study, we physiologically and genomically characterized a newly discovered thaumarchaeon from the deep-branching Nitrosocaldaceae family of which we have obtained a high (∼85%) enrichment from biofilm of an Icelandic hot spring (73°C). This AOA, which we provisionally refer to as “Candidatus Nitrosocaldus islandicus,” is an obligately thermophilic, aerobic chemolithoautotrophic ammonia oxidizer, which stoichiometrically converts ammonia to nitrite at temperatures between 50 and 70°C. “Ca. N. islandicus” encodes the expected repertoire of enzymes proposed to be required for archaeal ammonia oxidation, but unexpectedly lacks a nirK gene and also possesses no identifiable other enzyme for nitric oxide (NO) generation§. Nevertheless, ammonia oxidation by this AOA appears to be NO-dependent as “Ca. N. islandicus” is, like all other tested AOA, inhibited by the addition of an NO scavenger. Furthermore, comparative genomics revealed that “Ca. N. islandicus” has the potential for aromatic amino acid fermentation as its genome encodes an indolepyruvate oxidoreductase (iorAB) as well as a type 3b hydrogenase, which are not present in any other sequenced AOA. A further surprising genomic feature of this thermophilic ammonia oxidizer is the absence of DNA polymerase D genes§ – one of the predominant replicative DNA polymerases in all other ammonia-oxidizing Thaumarchaeota. Collectively, our findings suggest that metabolic versatility and DNA replication might differ substantially between obligately thermophilic and

Cultivation and Genomic Analysis of “Candidatus Nitrosocaldus islandicus,” an Obligately Thermophilic, Ammonia-Oxidizing Thaumarchaeon from a Hot Spring Biofilm in Graendalur Valley, Iceland

Directory of Open Access Journals (Sweden)

Anne Daebeler

2018-02-01

Full Text Available Ammonia-oxidizing archaea (AOA within the phylum Thaumarchaeota are the only known aerobic ammonia oxidizers in geothermal environments. Although molecular data indicate the presence of phylogenetically diverse AOA from the Nitrosocaldus clade, group 1.1b and group 1.1a Thaumarchaeota in terrestrial high-temperature habitats, only one§ enrichment culture of an AOA thriving above 50°C has been reported and functionally analyzed. In this study, we physiologically and genomically characterized a newly discovered thaumarchaeon from the deep-branching Nitrosocaldaceae family of which we have obtained a high (∼85% enrichment from biofilm of an Icelandic hot spring (73°C. This AOA, which we provisionally refer to as “Candidatus Nitrosocaldus islandicus,” is an obligately thermophilic, aerobic chemolithoautotrophic ammonia oxidizer, which stoichiometrically converts ammonia to nitrite at temperatures between 50 and 70°C. “Ca. N. islandicus” encodes the expected repertoire of enzymes proposed to be required for archaeal ammonia oxidation, but unexpectedly lacks a nirK gene and also possesses no identifiable other enzyme for nitric oxide (NO generation§. Nevertheless, ammonia oxidation by this AOA appears to be NO-dependent as “Ca. N. islandicus” is, like all other tested AOA, inhibited by the addition of an NO scavenger. Furthermore, comparative genomics revealed that “Ca. N. islandicus” has the potential for aromatic amino acid fermentation as its genome encodes an indolepyruvate oxidoreductase (iorAB as well as a type 3b hydrogenase, which are not present in any other sequenced AOA. A further surprising genomic feature of this thermophilic ammonia oxidizer is the absence of DNA polymerase D genes§ – one of the predominant replicative DNA polymerases in all other ammonia-oxidizing Thaumarchaeota. Collectively, our findings suggest that metabolic versatility and DNA replication might differ substantially between obligately

Nitrification and the ammonia-oxidizing communities in the central Baltic Sea water column

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Jäntti, Helena; Ward, Bess B.; Dippner, Joachim W.; Hietanen, Susanna

2018-03-01

The redoxclines that form between the oxic and anoxic water layers in the central Baltic Sea are sites of intensive nitrogen cycling. To gain better understanding of nitrification, we measured the biogeochemical properties along with potential nitrification rates and analyzed the assemblages of ammonia-oxidizing bacteria and archaea using functional gene microarrays. To estimate nitrification in the entire water column, we constructed a regression model for the nitrification rates and applied it to the conditions prevailing in the area in 2008-2012. The highest ammonia oxidation rates were found in a thin layer at the top of the redoxcline and the rates quickly decreased below detection limit when oxygen was exhausted. This is probably because extensive suboxic layers, which are known to harbor pelagic nitrification, are formed only for short periods after inflows in the Baltic Sea. The nitrification rates were some of the highest measured in the water columns, but the thickness of the layer where conditions were favorable for nitrification, was very small and it remained fairly stable between years. However, the depth of the nitrification layer varied substantially between years, particularly in the eastern Gotland Basin (EGB) due to turbulence in the water column. The ammonia oxidizer communities clustered differently between the eastern and western Gotland Basin (WGB) and the composition of ammonia-oxidizing assemblages correlated with the environmental variables. The ammonia oxidizer community composition was more even in the EGB, which may be related to physical instability of the redoxcline that does not allow predominance of a single archetype, whereas in the WGB, where the position of the redoxcline is more constant, the ammonia-oxidizing community was less even. Overall the ammonia-oxidizing communities in the Baltic Sea redoxclines were very evenly distributed compared to other marine environments where microarrays have been applied previously.

Differential contributions of ammonia oxidizers and nitrite oxidizers to nitrification in four paddy soils

Science.gov (United States)

Wang, Baozhan; Zhao, Jun; Guo, Zhiying; Ma, Jing; Xu, Hua; Jia, Zhongjun

2015-01-01

Rice paddy fields are characterized by regular flooding and nitrogen fertilization, but the functional importance of aerobic ammonia oxidizers and nitrite oxidizers under unique agricultural management is poorly understood. In this study, we report the differential contributions of ammonia-oxidizing archaea (AOA), bacteria (AOB) and nitrite-oxidizing bacteria (NOB) to nitrification in four paddy soils from different geographic regions (Zi-Yang (ZY), Jiang-Du (JD), Lei-Zhou (LZ) and Jia-Xing (JX)) that are representative of the rice ecosystems in China. In urea-amended microcosms, nitrification activity varied greatly with 11.9, 9.46, 3.03 and 1.43 μg NO3−-N g−1 dry weight of soil per day in the ZY, JD, LZ and JX soils, respectively, over the course of a 56-day incubation period. Real-time quantitative PCR of amoA genes and pyrosequencing of 16S rRNA genes revealed significant increases in the AOA population to various extents, suggesting that their relative contributions to ammonia oxidation activity decreased from ZY to JD to LZ. The opposite trend was observed for AOB, and the JX soil stimulated only the AOB populations. DNA-based stable-isotope probing further demonstrated that active AOA numerically outcompeted their bacterial counterparts by 37.0-, 10.5- and 1.91-fold in 13C-DNA from ZY, JD and LZ soils, respectively, whereas AOB, but not AOA, were labeled in the JX soil during active nitrification. NOB were labeled to a much greater extent than AOA and AOB, and the addition of acetylene completely abolished the assimilation of 13CO2 by nitrifying populations. Phylogenetic analysis suggested that archaeal ammonia oxidation was predominantly catalyzed by soil fosmid 29i4-related AOA within the soil group 1.1b lineage. Nitrosospira cluster 3-like AOB performed most bacterial ammonia oxidation in the ZY, LZ and JX soils, whereas the majority of the 13C-AOB in the JD soil was affiliated with the Nitrosomona communis lineage. The 13C-NOB was overwhelmingly

Interactions between ammonia and nitrite oxidizing bacteria in co-cultures: Is there evidence for mutualism, commensalism, or competition?

Energy Technology Data Exchange (ETDEWEB)

Sayavedra-Soto, Luis [Oregon State Univ., Corvallis, OR (United States); Arp, Daniel [Oregon State Univ., Corvallis, OR (United States)

2017-08-01

Nitrification is a two-step environmental microbial process in the nitrogen cycle in which ammonia is oxidized to nitrate. Ammonia-oxidizing bacteria and archaea oxidize ammonia to nitrite and nitrite is oxidized to nitrate by nitrite-oxidizing bacteria. These microorganisms, which likely act in concert in a microbial community, play critical roles in the movement of inorganic N in soils, sediments and waters and are essential to the balance of the nitrogen cycle. Anthropogenic activity has altered the balance of the nitrogen cycle through agriculture practices and organic waste byproducts. Through their influence on available N for plant growth, nitrifying microorganisms influence plant productivity for food and fiber production and the associated carbon sequestration. N Fertilizer production, primarily as ammonia, requires large inputs of natural gas and hydrogen. In croplands fertilized with ammonia-based fertilizers, nitrifiers contribute to the mobilization of this N by producing nitrate (NO3-), wasting the energy used in the production and application of ammonia-based fertilizer. The resulting nitrate is readily leached from these soils, oxidized to gaseous N oxides (greenhouse gases), and denitrified to N2 (which is no longer available as a plant N source). Still, ammonia oxidizers are beneficial in the treatment of wastewater and they also show potential to contribute to microbial bioremediation strategies for clean up of environments contaminated with chlorinated hydrocarbons. Mitigation of the negative effects and exploitation of the beneficial effects of nitrifiers will be facilitated by a systems-level understanding of the interactions of ammonia-oxidizing bacteria and nitrite-oxidizing bacteria with the environment and with each other.

Energy Metabolism during Anaerobic Methane Oxidation in ANME Archaea

Science.gov (United States)

McGlynn, Shawn E.

2017-01-01

Anaerobic methane oxidation in archaea is often presented to operate via a pathway of “reverse methanogenesis”. However, if the cumulative reactions of a methanogen are run in reverse there is no apparent way to conserve energy. Recent findings suggest that chemiosmotic coupling enzymes known from their use in methylotrophic and acetoclastic methanogens—in addition to unique terminal reductases—biochemically facilitate energy conservation during complete CH4 oxidation to CO2. The apparent enzyme modularity of these organisms highlights how microbes can arrange their energy metabolisms to accommodate diverse chemical potentials in various ecological niches, even in the extreme case of utilizing “reverse” thermodynamic potentials. PMID:28321009

Adaptation of ammonia-oxidizing microorganisms to environment shift of paddy field soil.

Science.gov (United States)

Ke, Xiubin; Lu, Yahai

2012-04-01

Adaptation of microorganisms to the environment is a central theme in microbial ecology. The objective of this study was to investigate the response of ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) to a soil medium shift. We employed two rice field soils collected from Beijing and Hangzhou, China. These soils contained distinct AOB communities dominated by Nitrosomonas in Beijing rice soil and Nitrosospira in Hangzhou rice soil. Three mixtures were generated by mixing equal quantities of Beijing soil and Hangzhou soil (BH), Beijing soil with sterilized Hangzhou soil (BSH), and Hangzhou soil with sterilized Beijing soil (HSB). Pure and mixed soils were permanently flooded, and the surface-layer soil where ammonia oxidation occurred was collected to determine the response of AOB and AOA to the soil medium shift. AOB populations increased during the incubation, and the rates were initially faster in Beijing soil than in Hangzhou soil. Nitrosospira (cluster 3a) and Nitrosomonas (communis cluster) increased with time in correspondence with ammonia oxidation in the Hangzhou and Beijing soils, respectively. The 'BH' mixture exhibited a shift from Nitrosomonas at day 0 to Nitrosospira at days 21 and 60 when ammonia oxidation became most active. In 'HSB' and 'BSH' mixtures, Nitrosospira showed greater stimulation than Nitrosomonas, both with and without N amendment. These results suggest that Nitrosospira spp. were better adapted to soil environment shifts than Nitrosomonas. Analysis of the AOA community revealed that the composition of AOA community was not responsive to the soil environment shifts or to nitrogen amendment. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Candidatus Nitrosocaldus cavascurensis, an Ammonia Oxidizing, Extremely Thermophilic Archaeon with a Highly Mobile Genome

OpenAIRE

Abby, Sophie S.; Melcher, Michael; Kerou, Melina; Krupovic, Mart; Stieglmeier, Michaela; Rossel, Claudia; Pfeifer, Kevin; Schleper, Christa

2018-01-01

Ammonia oxidizing archaea (AOA) of the phylum Thaumarchaeota are widespread in moderate environments but their occurrence and activity has also been demonstrated in hot springs. Here we present the first enrichment of a thermophilic representative with a sequenced genome, which facilitates the search for adaptive strategies and for traits that shape the evolution of Thaumarchaeota. Candidatus Nitrosocaldus cavascurensis has been enriched from a hot spring in Ischia, Italy. It grows optimally ...

Ammonium supply rate influences archaeal and bacterial ammonia oxidizers in a wetland soil vertical profile.

Science.gov (United States)

Höfferle, Špela; Nicol, Graeme W; Pal, Levin; Hacin, Janez; Prosser, James I; Mandić-Mulec, Ines

2010-11-01

Oxidation of ammonia, the first step in nitrification, is carried out in soil by bacterial and archaeal ammonia oxidizers and recent studies suggest possible selection for the latter in low-ammonium environments. In this study, we investigated the selection of ammonia-oxidizing archaea and bacteria in wetland soil vertical profiles at two sites differing in terms of the ammonium supply rate, but not significantly in terms of the groundwater level. One site received ammonium through decomposition of organic matter, while the second, polluted site received a greater supply, through constant leakage of an underground septic tank. Soil nitrification potential was significantly greater at the polluted site. Quantification of amoA genes demonstrated greater abundance of bacterial than archaeal amoA genes throughout the soil profile at the polluted site, whereas bacterial amoA genes at the unpolluted site were below the detection limit. At both sites, archaeal, but not the bacterial community structure was clearly stratified with depth, with regard to the soil redox potential imposed by groundwater level. However, depth-related changes in the archaeal community structure may also be associated with physiological functions other than ammonia oxidation. © 2010 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

Changes in N-transforming archaea and bacteria in soil during the establishment of bioenergy crops.

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Yuejian Mao

Full Text Available Widespread adaptation of biomass production for bioenergy may influence important biogeochemical functions in the landscape, which are mainly carried out by soil microbes. Here we explore the impact of four potential bioenergy feedstock crops (maize, switchgrass, Miscanthus X giganteus, and mixed tallgrass prairie on nitrogen cycling microorganisms in the soil by monitoring the changes in the quantity (real-time PCR and diversity (barcoded pyrosequencing of key functional genes (nifH, bacterial/archaeal amoA and nosZ and 16S rRNA genes over two years after bioenergy crop establishment. The quantities of these N-cycling genes were relatively stable in all four crops, except maize (the only fertilized crop, in which the population size of AOB doubled in less than 3 months. The nitrification rate was significantly correlated with the quantity of ammonia-oxidizing archaea (AOA not bacteria (AOB, indicating that archaea were the major ammonia oxidizers. Deep sequencing revealed high diversity of nifH, archaeal amoA, bacterial amoA, nosZ and 16S rRNA genes, with 229, 309, 330, 331 and 8989 OTUs observed, respectively. Rarefaction analysis revealed the diversity of archaeal amoA in maize markedly decreased in the second year. Ordination analysis of T-RFLP and pyrosequencing results showed that the N-transforming microbial community structures in the soil under these crops gradually differentiated. Thus far, our two-year study has shown that specific N-transforming microbial communities develop in the soil in response to planting different bioenergy crops, and each functional group responded in a different way. Our results also suggest that cultivation of maize with N-fertilization increases the abundance of AOB and denitrifiers, reduces the diversity of AOA, and results in significant changes in the structure of denitrification community.

Diversity of Archaea in Brazilian savanna soils.

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Catão, E; Castro, A P; Barreto, C C; Krüger, R H; Kyaw, C M

2013-07-01

Although the richness of Bacteria and Fungi in Cerrado' soils has been reported, here we report, for the first time, the archaeal community in Cerrado's soils. DNA extracted from soil of two distinct vegetation types, a dense subtype of sensu strict (cerrado denso) and riverbank forest (mata de galeria), was used to amplify Archaea-specific 16S rRNA gene. All of the fragments sequenced were classified as Archaea into the phylum Thaumarchaeota, predominantly affiliated to groups I.1b and I.1c. Sequences affiliated to the group I.1a were found only in the soil from riverbank forest. Soils from 'cerrado denso' had greater Archaea richness than those from 'mata de galeria' based on the richness indexes and on the rarefaction curve. β-Diversity analysis showed significant differences between the sequences from the two soil areas studied because of their different thaumarchaeal group composition. These results provide information about the third domain of life from Cerrado soils.

Cultivation and characterization of Candidatus Nitrosocosmicus exaquare, an ammonia-oxidizing archaeon from a municipal wastewater treatment system.

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Sauder, Laura A; Albertsen, Mads; Engel, Katja; Schwarz, Jasmin; Nielsen, Per H; Wagner, Michael; Neufeld, Josh D

2017-05-01

Thaumarchaeota have been detected in several industrial and municipal wastewater treatment plants (WWTPs), despite the fact that ammonia-oxidizing archaea (AOA) are thought to be adapted to low ammonia environments. However, the activity, physiology and metabolism of WWTP-associated AOA remain poorly understood. We report the cultivation and complete genome sequence of Candidatus Nitrosocosmicus exaquare, a novel AOA representative from a municipal WWTP in Guelph, Ontario (Canada). In enrichment culture, Ca. N. exaquare oxidizes ammonia to nitrite stoichiometrically, is mesophilic, and tolerates at least 15 mm of ammonium chloride or sodium nitrite. Microautoradiography (MAR) for enrichment cultures demonstrates that Ca. N. exaquare assimilates bicarbonate in association with ammonia oxidation. However, despite using inorganic carbon, the ammonia-oxidizing activity of Ca. N. exaquare is greatly stimulated in enrichment culture by the addition of organic compounds, especially malate and succinate. Ca. N. exaquare cells are coccoid with a diameter of ~1-2 μm. Phylogenetically, Ca. N. exaquare belongs to the Nitrososphaera sister cluster within the Group I.1b Thaumarchaeota, a lineage which includes most other reported AOA sequences from municipal and industrial WWTPs. The 2.99 Mbp genome of Ca. N. exaquare encodes pathways for ammonia oxidation, bicarbonate fixation, and urea transport and breakdown. In addition, this genome encodes several key genes for dealing with oxidative stress, including peroxidase and catalase. Incubations of WWTP biofilm demonstrate partial inhibition of ammonia-oxidizing activity by 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl 3-oxide (PTIO), suggesting that Ca. N. exaquare-like AOA may contribute to nitrification in situ. However, CARD-FISH-MAR showed no incorporation of bicarbonate by detected Thaumarchaeaota, suggesting that detected AOA may incorporate non-bicarbonate carbon sources or rely on an alternative and yet unknown

Community Composition and Transcriptional Activity of Ammonia-Oxidizing Prokaryotes of Seagrass Thalassia hemprichii in Coral Reef Ecosystems

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Juan Ling

2018-01-01

Full Text Available Seagrasses in coral reef ecosystems play important ecological roles by enhancing coral reef resilience under ocean acidification. However, seagrass primary productivity is typically constrained by limited nitrogen availability. Ammonia oxidation is an important process conducted by ammonia-oxidizing archaea (AOA and bacteria (AOB, yet little information is available concerning the community structure and potential activity of seagrass AOA and AOB. Therefore, this study investigated the variations in the abundance, diversity and transcriptional activity of AOA and AOB at the DNA and transcript level from four sample types: the leaf, root, rhizosphere sediment and bulk sediment of seagrass Thalassia hemprichii in three coral reef ecosystems. DNA and complementary DNA (cDNA were used to prepare clone libraries and DNA and cDNA quantitative PCR (qPCR assays, targeting the ammonia monooxygenase-subunit (amoA genes as biomarkers. Our results indicated that the closest relatives of the obtained archaeal and bacterial amoA gene sequences recovered from DNA and cDNA libraries mainly originated from the marine environment. Moreover, all the obtained AOB sequences belong to the Nitrosomonadales cluster. Nearly all the AOA communities exhibited higher diversity than the AOB communities at the DNA level, but the qPCR data demonstrated that the abundances of AOB communities were higher than that of AOA communities based on both DNA and RNA transcripts. Collectively, most of the samples shared greater community composition similarity with samples from the same location rather than sample type. Furthermore, the abundance of archaeal amoA gene in rhizosphere sediments showed significant relationships with the ammonium concentration of sediments and the nitrogen content of plant tissue (leaf and root at the DNA level (P < 0.05. Conversely, no such relationships were found for the AOB communities. This work provides new insight into the nitrogen cycle

Responses of bacterial and archaeal ammonia oxidizers to soil organic and fertilizer amendments under long-term management

Energy Technology Data Exchange (ETDEWEB)

Wessen, E.; Nyberg, K.; Jansson, J.K.; Hallin, S.

2010-05-01

Ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) co-exist in soil, but their relative distribution may vary depending on the environmental conditions. Effects of changes in soil organic matter and nutrient content on the AOB and AOA are poorly understood. Our aim was to compare effects of long-term soil organic matter depletion and amendments with labile (straw) and more recalcitrant (peat) organic matter, with and without easily plant-available nitrogen, on the activities, abundances and community structures of AOB and AOA. Soil was sampled from a long-term field site in Sweden that was established in 1956. The potential ammonia oxidation rates, the AOB and AOA amoA gene abundances and the community structures of both groups based on T-RFLP of amoA genes were determined. Straw amendment during 50 years had not altered any of the measured soil parameters, while the addition of peat resulted in a significant increase of soil organic carbon as well as a decrease in pH. Nitrogen fertilization alone resulted in a small decrease in soil pH, organic carbon and total nitrogen, but an increase in primary production. Type and amount of organic matter had an impact on the AOB and AOA community structures and the AOA abundance. Our findings confirmed that AOA are abundant in soil, but showed that under certain conditions the AOB dominate, suggesting niche differentiation between the two groups at the field site. The large differences in potential rates between treatments correlated to the AOA community size, indicating that they were functionally more important in the nitrification process than the AOB. The AOA abundance was positively related to addition of labile organic carbon, which supports the idea that AOA could have alternative growth strategies using organic carbon. The AOB community size varied little in contrast to that of the AOA. This indicates that the bacterial ammonia oxidizers as a group have a greater ecophysiological diversity and

Down under the tunic: bacterial biodiversity hotspots and widespread ammonia-oxidizing archaea in coral reef ascidians.

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Erwin, Patrick M; Pineda, Mari Carmen; Webster, Nicole; Turon, Xavier; López-Legentil, Susanna

2014-03-01

Ascidians are ecologically important components of marine ecosystems yet the ascidian microbiota remains largely unexplored beyond a few model species. We used 16S rRNA gene tag pyrosequencing to provide a comprehensive characterization of microbial symbionts in the tunic of 42 Great Barrier Reef ascidian samples representing 25 species. Results revealed high bacterial biodiversity (3 217 unique operational taxonomic units (OTU0.03) from 19 described and 14 candidate phyla) and the widespread occurrence of ammonia-oxidizing Thaumarchaeota in coral reef ascidians (24 of 25 host species). The ascidian microbiota was clearly differentiated from seawater microbial communities and included symbiont lineages shared with other invertebrate hosts as well as unique, ascidian-specific phylotypes. Several rare seawater microbes were markedly enriched (200-700 fold) in the ascidian tunic, suggesting that the rare biosphere of seawater may act as a conduit for horizontal symbiont transfer. However, most OTUs (71%) were rare and specific to single hosts and a significant correlation between host relatedness and symbiont community similarity was detected, indicating a high degree of host-specificity and potential role of vertical transmission in structuring these communities. We hypothesize that the complex ascidian microbiota revealed herein is maintained by the dynamic microenvironments within the ascidian tunic, offering optimal conditions for different metabolic pathways such as ample chemical substrate (ammonia-rich host waste) and physical habitat (high oxygen, low irradiance) for nitrification. Thus, ascidian hosts provide unique and fertile niches for diverse microorganisms and may represent an important and previously unrecognized habitat for nitrite/nitrate regeneration in coral reef ecosystems.

Catalyst for Ammonia Oxidation

DEFF Research Database (Denmark)

2015-01-01

The present invention relates to a bimetallic catalyst for ammonia oxidation, a method for producing a bimetallic catalyst for ammonia oxidation and a method for tuning the catalytic activity of a transition metal. By depositing an overlayer of less catalytic active metal onto a more catalytic...

Ammonia-Oxidizing Archaea Are More Resistant Than Denitrifiers to Seasonal Precipitation Changes in an Acidic Subtropical Forest Soil

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Jie Chen

2017-07-01

Full Text Available Seasonal precipitation changes are increasingly severe in subtropical areas. However, the responses of soil nitrogen (N cycle and its associated functional microorganisms to such precipitation changes remain unclear. In this study, two projected precipitation patterns were manipulated: intensifying the dry-season drought (DD and extending the dry-season duration (ED but increasing the wet-season storms following the DD and ED treatment period. The effects of these two contrasting precipitation patterns on soil net N transformation rates and functional gene abundances were quantitatively assessed through a resistance index. Results showed that the resistance index of functional microbial abundance (-0.03 ± 0.08 was much lower than that of the net N transformation rate (0.55 ± 0.02 throughout the experiment, indicating that microbial abundance was more responsive to precipitation changes compared with the N transformation rate. Spring drought under the ED treatment significantly increased the abundances of both nitrifying (amoA and denitrifying genes (nirK, nirS, and nosZ, while changes in these gene abundances overlapped largely with control treatment during droughts in the dry season. Interestingly, the resistance index of the ammonia-oxidizing archaea (AOA amoA abundance was significantly higher than that of the denitrifying gene abundances, suggesting that AOA were more resistant to the precipitation changes. This was attributed to the stronger environmental adaptability and higher resource utilization efficiency of the AOA community, as indicated by the lack of correlations between AOA gene abundance and environmental factors [i.e., soil water content, ammonium (NH4+ and dissolved organic carbon concentrations] during the experiment.

Microbial nitrification in throughfall of a Japanese cedar associated with archaea from the tree canopy.

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Watanabe, Keiji; Kohzu, Ayato; Suda, Wataru; Yamamura, Shigeki; Takamatsu, Takejiro; Takenaka, Akio; Koshikawa, Masami Kanao; Hayashi, Seiji; Watanabe, Mirai

2016-01-01

To investigate the nitrification potential of phyllospheric microbes, we incubated throughfall samples collected under the canopies of Japanese cedar (Cryptomeria japonica) and analyzed the transformation of inorganic nitrogen in the samples. Nitrate concentration increased in the unfiltered throughfall after 4 weeks of incubation, but remained nearly constant in the filtered samples (pore size: 0.2 and 0.4 µm). In the unfiltered samples, δ(18)O and δ(15)N values of nitrate decreased during incubation. In addition, archaeal ammonia monooxygenase subunit A (amoA) genes, which participate in the oxidation of ammonia, were found in the throughfall samples, although betaproteobacterial amoA genes were not detected. The amoA genes recovered from the leaf surface of C. japonica were also from archaea. Conversely, nitrate production, decreased isotope ratios of nitrate, and the presence of amoA genes was not observed in rainfall samples collected from an open area. Thus, the microbial nitrification that occurred in the incubated throughfall is likely due to ammonia-oxidizing archaea that were washed off the tree canopy by precipitation.

Comparison among amoA Primers Suited for Quantification and Diversity Analyses of Ammonia-Oxidizing Bacteria in Soil

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Shimomura, Yumi; Morimoto, Sho; Hoshino, Yuko Takada; Uchida, Yoshitaka; Akiyama, Hiroko; Hayatsu, Masahito

2012-01-01

Ammonia monooxygenase subunit A gene (amoA) is frequently used as a functional gene marker for diversity analysis of ammonia-oxidizing bacteria (AOB). To select a suitable amoA primer for real-time PCR and PCR-denaturing gradient gel electrophoresis (DGGE), three reverse primers (degenerate primer amoA-2R; non-degenerate primers amoA-2R-GG and amoA-2IR) were examined. No significant differences were observed among the three primers in terms of quantitative values of amoA from environmental samples using real-time PCR. We found that PCR-DGGE analysis with the amoA-2IR primer gave the best results in this studied soil. These results indicate that amoA-2IR is a suitable primer for community analysis of AOB in the environment. PMID:22075625

Evaluation of autotrophic growth of ammonia-oxidizers associated with granular activated carbon used for drinking water purification by DNA-stable isotope probing.

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Niu, Jia; Kasuga, Ikuro; Kurisu, Futoshi; Furumai, Hiroaki; Shigeeda, Takaaki

2013-12-01

Nitrification is an important biological function of granular activated carbon (GAC) used in advanced drinking water purification processes. Newly discovered ammonia-oxidizing archaea (AOA) have challenged the traditional understanding of ammonia oxidation, which considered ammonia-oxidizing bacteria (AOB) as the sole ammonia-oxidizers. Previous studies demonstrated the predominance of AOA on GAC, but the contributions of AOA and AOB to ammonia oxidation remain unclear. In the present study, DNA-stable isotope probing (DNA-SIP) was used to investigate the autotrophic growth of AOA and AOB associated with GAC at two different ammonium concentrations (0.14 mg N/L and 1.4 mg N/L). GAC samples collected from three full-scale drinking water purification plants in Tokyo, Japan, had different abundance of AOA and AOB. These samples were fed continuously with ammonium and (13)C-bicarbonate for 14 days. The DNA-SIP analysis demonstrated that only AOA assimilated (13)C-bicarbonate at low ammonium concentration, whereas AOA and AOB exhibited autotrophic growth at high ammonium concentration. This indicates that a lower ammonium concentration is preferable for AOA growth. Since AOA could not grow without ammonium, their autotrophic growth was coupled with ammonia oxidation. Overall, our results point towards an important role of AOA in nitrification in GAC filters treating low concentration of ammonium. Copyright © 2013 Elsevier Ltd. All rights reserved.

Genetic diversity of archaea in deep-sea hydrothermal vent environments.

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Takai, K; Horikoshi, K

1999-08-01

Molecular phylogenetic analysis of naturally occurring archaeal communities in deep-sea hydrothermal vent environments was carried out by PCR-mediated small subunit rRNA gene (SSU rDNA) sequencing. As determined through partial sequencing of rDNA clones amplified with archaea-specific primers, the archaeal populations in deep-sea hydrothermal vent environments showed a great genetic diversity, and most members of these populations appeared to be uncultivated and unidentified organisms. In the phylogenetic analysis, a number of rDNA sequences obtained from deep-sea hydrothermal vents were placed in deep lineages of the crenarchaeotic phylum prior to the divergence of cultivated thermophilic members of the crenarchaeota or between thermophilic members of the euryarchaeota and members of the methanogen-halophile clade. Whole cell in situ hybridization analysis suggested that some microorganisms of novel phylotypes predicted by molecular phylogenetic analysis were likely present in deep-sea hydrothermal vent environments. These findings expand our view of the genetic diversity of archaea in deep-sea hydrothermal vent environments and of the phylogenetic organization of archaea.

The Co-Distribution of Nitrifying Archaea and Diazotrophic Bacteria in Geothermal Springs

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Hamilton, T. L.; Jewell, T. N. M.; de la Torre, J. R.; Boyd, E. S.

2014-12-01

Microbial processes that regulate availability of nutrients play key roles in shaping community composition. All life requires fixed nitrogen (N), and its bioavailability is what often limits ecosystem productivity. Biological nitrogen fixation, or the reduction of dinitrogen (N2) to ammonia (NH3), is a keystone process in N limited ecosystems, providing nitrogen for members of the community. N2 fixing organisms likely represent a 'bottom up control' on the structure of communities that develop in N limited environments. N2 fixation is catalyzed by a limited number of metabolically diverse bacteria and some methanogenic archaea and occurs in a variety of physically and geochemically diverse environments. Nitrification, or the sequential oxidation of NH4+ to nitrite (NO2-) and ultimately nitrate (NO3-), is catalyzed by several lineages of Proteobacteria at temperatures of < 62°C and by members of the Thaumarcheota at temperatures up to 90°C. Nitrification can thus be considered a 'top down control' on the structure of communities that develop in N limited environments. Our research in Yellowstone National Park (YNP) reveals a strong correspondence between the distribution of ammonia oxidizing archaea (AOA) and nitrogen fixing aquificae (NFA) in nitrogen-limited geothermal hot springs over large environmental gradients. Based on the physiology of AOA and NFA, we propose that the strong co-distributional pattern results from interspecies interactions, namely competition for bioavailable ammonia. Our recent work has shown that in springs where the niche dimension of AOA and NFA overlap (e.g., Perpetual Spouter; pH 7.1, 86.4°C), the dissimilar affinities for NH4 result in AOA metabolism maintaining a low NH4(T) pool and selecting for inclusion of NFA during the assembly of these communities. Here, we examine in situ physiological interactions of AOA and NFA, tracking changes in transcript levels of key genes involved in nitrogen metabolism and carbon fixation of

Spatial interaction of archaeal ammonia-oxidizers and nitrite-oxidizing bacteria in an unfertilized grassland soil

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Barbara eStempfhuber

2016-01-01

Full Text Available Interrelated successive transformation steps of nitrification are performed by distinct microbial groups – the ammonia-oxidizers, comprising ammonia-oxidizing archaea (AOA and bacteria (AOB, and nitrite-oxidizers such as Nitrobacter and Nitrospira, which are the dominant genera in the investigated soils. Hence, not only their presence and activity in the investigated habitat is required for nitrification, but also their temporal and spatial interactions. To demonstrate the interdependence of both groups and to address factors promoting putative niche differentiation within each group, temporal and spatial changes in nitrifying organisms were monitored in an unfertilized grassland site over an entire vegetation period at the plot scale of 10 m². Nitrifying organisms were assessed by measuring the abundance of marker genes (amoA for AOA and AOB, nxrA for Nitrobacter, 16S rRNA gene for Nitrospira selected for the respective sub-processes. A positive correlation between numerically dominant AOA and Nitrospira, and their co-occurrence at the same spatial scale in August and October, suggests that the nitrification process is predominantly performed by these groups and is restricted to a limited timeframe. Amongst nitrite-oxidizers, niche differentiation was evident in observed seasonally varying patterns of co-occurrence and spatial separation. While their distributions were most likely driven by substrate concentrations, oxygen availability may also have played a role under substrate-limited conditions. Phylogenetic analysis revealed temporal shifts in Nitrospira community composition with an increasing relative abundance of OTU03 assigned to sublineage V from August onwards, indicating its important role in nitrite oxidation.

The impact of genomics on research in diversity and evolution of archaea.

Science.gov (United States)

Mardanov, A V; Ravin, N V

2012-08-01

Since the definition of archaea as a separate domain of life along with bacteria and eukaryotes, they have become one of the most interesting objects of modern microbiology, molecular biology, and biochemistry. Sequencing and analysis of archaeal genomes were especially important for studies on archaea because of a limited availability of genetic tools for the majority of these microorganisms and problems associated with their cultivation. Fifteen years since the publication of the first genome of an archaeon, more than one hundred complete genome sequences of representatives of different phylogenetic groups have been determined. Analysis of these genomes has expanded our knowledge of biology of archaea, their diversity and evolution, and allowed identification and characterization of new deep phylogenetic lineages of archaea. The development of genome technologies has allowed sequencing the genomes of uncultivated archaea directly from enrichment cultures, metagenomic samples, and even from single cells. Insights have been gained into the evolution of key biochemical processes in archaea, such as cell division and DNA replication, the role of horizontal gene transfer in the evolution of archaea, and new relationships between archaea and eukaryotes have been revealed.

The growing tree of Archaea: new perspectives on their diversity, evolution and ecology.

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Adam, Panagiotis S; Borrel, Guillaume; Brochier-Armanet, Céline; Gribaldo, Simonetta

2017-11-01

The Archaea occupy a key position in the Tree of Life, and are a major fraction of microbial diversity. Abundant in soils, ocean sediments and the water column, they have crucial roles in processes mediating global carbon and nutrient fluxes. Moreover, they represent an important component of the human microbiome, where their role in health and disease is still unclear. The development of culture-independent sequencing techniques has provided unprecedented access to genomic data from a large number of so far inaccessible archaeal lineages. This is revolutionizing our view of the diversity and metabolic potential of the Archaea in a wide variety of environments, an important step toward understanding their ecological role. The archaeal tree is being rapidly filled up with new branches constituting phyla, classes and orders, generating novel challenges for high-rank systematics, and providing key information for dissecting the origin of this domain, the evolutionary trajectories that have shaped its current diversity, and its relationships with Bacteria and Eukarya. The present picture is that of a huge diversity of the Archaea, which we are only starting to explore.

Diversity and stratification of archaea in a hypersaline microbial mat.

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Robertson, Charles E; Spear, John R; Harris, J Kirk; Pace, Norman R

2009-04-01

The Guerrero Negro (GN) hypersaline microbial mats have become one focus for biogeochemical studies of stratified ecosystems. The GN mats are found beneath several of a series of ponds of increasing salinity that make up a solar saltern fed from Pacific Ocean water pumped from the Laguna Ojo de Liebre near GN, Baja California Sur, Mexico. Molecular surveys of the laminated photosynthetic microbial mat below the fourth pond in the series identified an enormous diversity of bacteria in the mat, but archaea have received little attention. To determine the bulk contribution of archaeal phylotypes to the pond 4 study site, we determined the phylogenetic distribution of archaeal rRNA gene sequences in PCR libraries based on nominally universal primers. The ratios of bacterial/archaeal/eukaryotic rRNA genes, 90%/9%/1%, suggest that the archaeal contribution to the metabolic activities of the mat may be significant. To explore the distribution of archaea in the mat, sequences derived using archaeon-specific PCR primers were surveyed in 10 strata of the 6-cm-thick mat. The diversity of archaea overall was substantial albeit less than the diversity observed previously for bacteria. Archaeal diversity, mainly euryarchaeotes, was highest in the uppermost 2 to 3 mm of the mat and decreased rapidly with depth, where crenarchaeotes dominated. Only 3% of the sequences were specifically related to known organisms including methanogens. While some mat archaeal clades corresponded with known chemical gradients, others did not, which is likely explained by heretofore-unrecognized gradients. Some clades did not segregate by depth in the mat, indicating broad metabolic repertoires, undersampling, or both.

Community size and composition of ammonia oxidizers and denitrifiers in an alluvial intertidal wetland ecosystem

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Ziye eHu

2014-07-01

Full Text Available Global nitrogen cycling is mainly mediated by the activity of microorganisms. Nitrogen cycle processes are mediated by functional groups of microorganisms that are affected by constantly changing environmental conditions and substrate availability. In this study, we investigated the temporal and spatial patterns of nitrifier and denitrifier communities in an intertidal wetland. Soil samples were collected over four distinct seasons from three locations with different vegetative cover. Multiple environmental factors and process rates were measured and analyzed together with the community size and composition profiles. We observed that the community size and composition of the nitrifiers and denitrifiers are affected significantly by seasonal factors, while vegetative cover affected the community composition. The seasonal impacts on the community size of ammonia oxidizing archaea (AOA are much higher than that of ammonia oxidizing bacteria (AOB. The seasonal change was a more important indicator for AOA community composition patterns, while vegetation was more important for the AOB community patterns. The microbial process rates were correlated with both the community size and composition.

Dissimilatory oxidation and reduction of elemental sulfur in thermophilic archaea.

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Kletzin, Arnulf; Urich, Tim; Müller, Fabian; Bandeiras, Tiago M; Gomes, Cláudio M

2004-02-01

The oxidation and reduction of elemental sulfur and reduced inorganic sulfur species are some of the most important energy-yielding reactions for microorganisms living in volcanic hot springs, solfataras, and submarine hydrothermal vents, including both heterotrophic, mixotrophic, and chemolithoautotrophic, carbon dioxide-fixing species. Elemental sulfur is the electron donor in aerobic archaea like Acidianus and Sulfolobus. It is oxidized via sulfite and thiosulfate in a pathway involving both soluble and membrane-bound enzymes. This pathway was recently found to be coupled to the aerobic respiratory chain, eliciting a link between sulfur oxidation and oxygen reduction at the level of the respiratory heme copper oxidase. In contrast, elemental sulfur is the electron acceptor in a short electron transport chain consisting of a membrane-bound hydrogenase and a sulfur reductase in (facultatively) anaerobic chemolithotrophic archaea Acidianus and Pyrodictium species. It is also the electron acceptor in organoheterotrophic anaerobic species like Pyrococcus and Thermococcus, however, an electron transport chain has not been described as yet. The current knowledge on the composition and properties of the aerobic and anaerobic pathways of dissimilatory elemental sulfur metabolism in thermophilic archaea is summarized in this contribution.

Abundance and diversity of archaeal accA gene in hot springs in Yunnan Province, China.

Science.gov (United States)

Song, Zhao-Qi; Wang, Li; Wang, Feng-Ping; Jiang, Hong-Chen; Chen, Jin-Quan; Zhou, En-Min; Liang, Feng; Xiao, Xiang; Li, Wen-Jun

2013-09-01

It has been suggested that archaea carrying the accA gene, encoding the alpha subunit of the acetyl CoA carboxylase, autotrophically fix CO2 using the 3-hydroxypropionate/4-hydroxybutyrate pathway in low-temperature environments (e.g., soils, oceans). However, little new information has come to light regarding the occurrence of archaeal accA genes in high-temperature ecosystems. In this study, we investigated the abundance and diversity of archaeal accA gene in hot springs in Yunnan Province, China, using DNA- and RNA-based phylogenetic analyses and quantitative polymerase chain reaction. The results showed that archaeal accA genes were present and expressed in the investigated Yunnan hot springs with a wide range of temperatures (66-96 °C) and pH (4.3-9.0). The majority of the amplified archaeal accA gene sequences were affiliated with the ThAOA/HWCG III [thermophilic ammonia-oxidizing archaea (AOA)/hot water crenarchaeotic group III]. The archaeal accA gene abundance was very close to that of AOA amoA gene, encoding the alpha subunit of ammonia monooxygenase. These data suggest that AOA in terrestrial hot springs might acquire energy from ammonia oxidation coupled with CO2 fixation using the 3-hydroxypropionate/4-hydroxybutyrate pathway.

Physiological plasticity of the thermophilic ammonia oxidizing archaeon Nitrosocaldus yellowstonii in response to a changing environment

Science.gov (United States)

Jewell, T.; Johnson, A.; Gelsinger, D.; de la Torre, J. R.

2012-12-01

Our understanding of nitrogen biogeochemical cycling in high temperature environments underwent a dramatic revision with the discovery of ammonia oxidizing archaea (AOA). The importance of AOA to the global nitrogen cycle came to light when recent studies of marine AOA demonstrated the dominance of these organisms in the ocean microbiome and their role as producers of the greenhouse gas nitrous oxide (N2O). Understanding how AOA respond to fluctuating environments is crucial to fully comprehending their contribution to global biogeochemical cycling and climate change. In this study we use the thermophilic AOA Nitrosocaldus yellowstonii strain HL72 to explore the physiological plasticity of energy metabolism in these organisms. Previous studies have shown that HL72 grows autotrophically by aerobically oxidizing ammonia (NH3) to nitrite (NO2-). Unlike studies of marine AOA, we find that HL72 can grow over a wide ammonia concentration range (0.25 - 10 mM NH4Cl) with comparable generation times when in the presence of 0.25 to 4 mM NH4Cl. However, preliminary data indicate that amoA, the alpha subunit of ammonia monooxygenase (AMO), is upregulated at low ammonia concentrations (<50 μM) compared to growth at 1 mM. Although the ammonia oxidation pathway has not been fully elucidated, we have shown that nitric oxide (NO) appears to be a key intermediate: exponentially growing HL72 produces significant NO and the removal of NO using a scavenger reversibly inhibits growth. In addition to AMO, the HL72 genome also contains sequences for a urease encoded by subunits ureABC and an active urea transporter. Urea ((NH2)2CO) is an organic compound ubiquitous to aquatic and soil habitats that, when hydrolyzed, forms NH3 and CO2. We examined urea as an alternate source of ammonia for the ammonia oxidation pathway. HL72 grows over a wide range of urea concentrations (0.25 - 10 mM) at rates comparable to growth on ammonia. In a substrate competition experiment HL72 preferentially

Hydrothermal oxidation of ammonia/organic waste mixtures

International Nuclear Information System (INIS)

Luan, Li; Proesmans, P.I.; Buelow, S.J.

1997-01-01

Hydrothermal oxidation is a promising new technology for the treatment of radioactive contaminated hazardous organic wastes. Los Alamos National Laboratory is currently evaluating this technology for the U. S. Department of Energy. In this paper, we present experimental results from the study of the hydrothermal oxidation of an ammonia/alcohol/uranium waste mixture. The use of a co-oxidant system consisting of hydrogen peroxide combined with nitrate is discussed. Experiments demonstrate near complete destruction of ammonia and organic compounds at 500 degrees C, 38 MPa, and 50 seconds reaction time. The ammonia and total organic carbon (TOC) concentrations in a waste simulant is reduced from 8,500 mg/L of ammonia and 12,500 mg/L TOC to 30 mg/L ammonia and less than 10 mg/L TOC. The major reaction products are CO 2 , N 2 , and a small amount of N 2 O. Comparison experiments with nitrate and hydrogen peroxide used individually show the advantage of the co-oxidant system

Potential nitrous oxide yield of AOA vs. AOB and utilization of carbon and nitrogen in the ammonia oxidizing process in the Pearl River Estuary

Science.gov (United States)

Ma, L.; Dai, M.; Tan, S.; Xia, X.; Liu, H.

2016-12-01

Nitrous oxide (N2O), a greenhouse gas, is a by-product during ammonia oxidation process, the production of which is often stimulated under low dissolved oxygen (DO) in the estuarine environment. The potential yield of N2O has been considered to be driven by ammonia-oxidizing bacteria (AOB) of Betaproteobacteria & Gammaproteobacteria and/or ammonia-oxidizing archaea (AOA) of Thaumarchaeota. In order to examine the relative importance of AOA and AOB in producing N2O and in modulating the potential N2O yield, arch-amoA, beta-amoA, gamma-amoA encoding for the alpha subunit of the ammonia monooxygenase (AMO) are used as biomarkers to identify the distributions and bioactivities of AOA and AOB in the Pearl River Estuary (PRE). Size fractionation experiments were conducted to distinguish AOA and AOB on particles in different size-fractions of > 3 μm, 0.45-3 μm, and 0.22-0.45 μm. Pure culture of N. maritimusSCM1 was studied as a model organism to identify the organic carbon production during ammonia oxidation by SCM1 strains. Our results show that AOA distributes largely in the free-living state and could adapt to very limited ammonia substrate and low saturation of DO; AOB mainly distributes at the particle-attached state under relative richer ammonia and high DO conditions; however, the RNA/DNA ratio of AOB was higher than that of AOA under the same conditions suggesting AOB is relatively more actively expressed. In the upper reach of PRE, the dominant microorganism in the water column was AOB and the in situ N2O/NH3 therein ranged 0.73-3.74 ‰. In the lower PRE, AOA was dominated, and the in situ N2O/NH3 was of 1.17- 7.32‰. At selected sites, we estimated isotope effect (e) of AOA (eDIC/bulk) as -23.94‰ and AOB (eDIC/bulk) as -56.6‰ to -44.8‰, which is consistent with the studies of pure cultures. The coefficient of C sequestration "k", defined as (C biomass / DIC in situ) / (N biomass / ammonia in situ) to differ the utilization of carbon and nitrogen, of

Diversity of archaea and bacteria in a biogas reactor fed with ...

African Journals Online (AJOL)

Diversity of archaea and bacteria in a biogas reactor fed with Pennisetum sinese ... AFRICAN JOURNALS ONLINE (AJOL) · Journals · Advanced Search · USING ... rumen microbial community in a biogas reactor by 16S rRNA gene analysis, ...

Linking isoprenoidal GDGT membrane lipid distributions with gene abundances of ammonia-oxidizing

NARCIS (Netherlands)

Buckles, L.K.; Villanueva, L.; Weijers, J.W.H.; Verschuren, D.; Sinninghe Damsté, J.S.

2013-01-01

Stratified lakes are important reservoirs of microbial diversity and provide habitats for niche differentiation of Archaea. In this study, we used a lipid biomarker/DNA-based approach to reveal the diversity and abundance of Archaea in the water column of Lake Challa (East Africa). Concentrations of

Ammonia removal in electrochemical oxidation: Mechanism and pseudo-kinetics

International Nuclear Information System (INIS)

Li Liang; Liu Yan

2009-01-01

This paper investigated the mechanism and pseudo-kinetics for removal of ammonia by electrochemical oxidation with RuO 2 /Ti anode using batch tests. The results show that the ammonia oxidation rates resulted from direct oxidation at electrode-liquid interfaces of the anode by stepwise dehydrogenation, and from indirect oxidation by hydroxyl radicals were so slow that their contribution to ammonia removal was negligible under the condition with Cl - . The oxidation rates of ammonia ranged from 1.0 to 12.3 mg N L -1 h -1 and efficiency reached nearly 100%, primarily due to the indirect oxidation of HOCl, and followed pseudo zero-order kinetics in electrochemical oxidation with Cl - . About 88% ammonia was removed from the solution. The removed one was subsequently found in the form of N 2 in the produced gas. The rate at which Cl - lost electrons at the anode was a major factor in the overall ammonia oxidation. Current density and Cl - concentration affected the constant of the pseudo zero-order kinetics, expressed by k = 0.0024[Cl - ] x j. The ammonia was reduced to less than 0.5 mg N L -1 after 2 h of electrochemical oxidation for the effluent from aerobic or anaerobic reactors which treated municipal wastewater. This result was in line with the strict discharge requirements

Enrichment and genome sequence of the group I.1a ammonia-oxidizing Archaeon "Ca. Nitrosotenuis uzonensis" representing a clade globally distributed in thermal habitats.

Directory of Open Access Journals (Sweden)

Elena V Lebedeva

Full Text Available The discovery of ammonia-oxidizing archaea (AOA of the phylum Thaumarchaeota and the high abundance of archaeal ammonia monooxygenase subunit A encoding gene sequences in many environments have extended our perception of nitrifying microbial communities. Moreover, AOA are the only aerobic ammonia oxidizers known to be active in geothermal environments. Molecular data indicate that in many globally distributed terrestrial high-temperature habits a thaumarchaeotal lineage within the Nitrosopumilus cluster (also called "marine" group I.1a thrives, but these microbes have neither been isolated from these systems nor functionally characterized in situ yet. In this study, we report on the enrichment and genomic characterization of a representative of this lineage from a thermal spring in Kamchatka. This thaumarchaeote, provisionally classified as "Candidatus Nitrosotenuis uzonensis", is a moderately thermophilic, non-halophilic, chemolithoautotrophic ammonia oxidizer. The nearly complete genome sequence (assembled into a single scaffold of this AOA confirmed the presence of the typical thaumarchaeotal pathways for ammonia oxidation and carbon fixation, and indicated its ability to produce coenzyme F420 and to chemotactically react to its environment. Interestingly, like members of the genus Nitrosoarchaeum, "Candidatus N. uzonensis" also possesses a putative artubulin-encoding gene. Genome comparisons to related AOA with available genome sequences confirmed that the newly cultured AOA has an average nucleotide identity far below the species threshold and revealed a substantial degree of genomic plasticity with unique genomic regions in "Ca. N. uzonensis", which potentially include genetic determinants of ecological niche differentiation.

Enrichment and genome sequence of the group I.1a ammonia-oxidizing Archaeon "Ca. Nitrosotenuis uzonensis" representing a clade globally distributed in thermal habitats.

Science.gov (United States)

Lebedeva, Elena V; Hatzenpichler, Roland; Pelletier, Eric; Schuster, Nathalie; Hauzmayer, Sandra; Bulaev, Aleksandr; Grigor'eva, Nadezhda V; Galushko, Alexander; Schmid, Markus; Palatinszky, Marton; Le Paslier, Denis; Daims, Holger; Wagner, Michael

2013-01-01

The discovery of ammonia-oxidizing archaea (AOA) of the phylum Thaumarchaeota and the high abundance of archaeal ammonia monooxygenase subunit A encoding gene sequences in many environments have extended our perception of nitrifying microbial communities. Moreover, AOA are the only aerobic ammonia oxidizers known to be active in geothermal environments. Molecular data indicate that in many globally distributed terrestrial high-temperature habits a thaumarchaeotal lineage within the Nitrosopumilus cluster (also called "marine" group I.1a) thrives, but these microbes have neither been isolated from these systems nor functionally characterized in situ yet. In this study, we report on the enrichment and genomic characterization of a representative of this lineage from a thermal spring in Kamchatka. This thaumarchaeote, provisionally classified as "Candidatus Nitrosotenuis uzonensis", is a moderately thermophilic, non-halophilic, chemolithoautotrophic ammonia oxidizer. The nearly complete genome sequence (assembled into a single scaffold) of this AOA confirmed the presence of the typical thaumarchaeotal pathways for ammonia oxidation and carbon fixation, and indicated its ability to produce coenzyme F420 and to chemotactically react to its environment. Interestingly, like members of the genus Nitrosoarchaeum, "Candidatus N. uzonensis" also possesses a putative artubulin-encoding gene. Genome comparisons to related AOA with available genome sequences confirmed that the newly cultured AOA has an average nucleotide identity far below the species threshold and revealed a substantial degree of genomic plasticity with unique genomic regions in "Ca. N. uzonensis", which potentially include genetic determinants of ecological niche differentiation.

Immobilization of ammonia-oxidizing bacteria by polyvinyl alcohol and sodium alginate.

Science.gov (United States)

Dong, Yuwei; Zhang, Yanqiu; Tu, Baojun

Ammonia-oxidizing bacteria were immobilized by polyvinyl alcohol (PVA) and sodium alginate. The immobilization conditions and ammonia oxidation ability of the immobilized bacteria were investigated. The following immobilization conditions were observed to be optimal: PVA, 12%; sodium alginate, 1.1%; calcium chloride, 1.0%; inoculum concentration, 1.3 immobilized balls/mL of immobilized medium; pH, 10; and temperature, 30°C. The immobilized ammonia-oxidizing bacteria exhibited strong ammonia oxidation ability even after being recycled four times. The ammonia nitrogen removal rate of the immobilized ammonia-oxidizing bacteria reached 90.30% under the optimal immobilization conditions. When compared with ammonia-oxidizing bacteria immobilized by sodium alginate alone, the bacteria immobilized by PVA and sodium alginate were superior with respect to pH resistance, the number of reuses, material cost, heat resistance, and ammonia oxidation ability. Copyright © 2017 Sociedade Brasileira de Microbiologia. Published by Elsevier Editora Ltda. All rights reserved.

Candidatus Nitrosocaldus cavascurensis, an Ammonia Oxidizing, Extremely Thermophilic Archaeon with a Highly Mobile Genome.

Science.gov (United States)

Abby, Sophie S; Melcher, Michael; Kerou, Melina; Krupovic, Mart; Stieglmeier, Michaela; Rossel, Claudia; Pfeifer, Kevin; Schleper, Christa

2018-01-01

Ammonia oxidizing archaea (AOA) of the phylum Thaumarchaeota are widespread in moderate environments but their occurrence and activity has also been demonstrated in hot springs. Here we present the first enrichment of a thermophilic representative with a sequenced genome, which facilitates the search for adaptive strategies and for traits that shape the evolution of Thaumarchaeota. Candidatus Nitrosocaldus cavascurensis has been enriched from a hot spring in Ischia, Italy. It grows optimally at 68°C under chemolithoautotrophic conditions on ammonia or urea converting ammonia stoichiometrically into nitrite with a generation time of approximately 23 h. Phylogenetic analyses based on ribosomal proteins place the organism as a sister group to all known mesophilic AOA. The 1.58 Mb genome of Ca. N. cavascurensis harbors an amo AXCB gene cluster encoding ammonia monooxygenase and genes for a 3-hydroxypropionate/4-hydroxybutyrate pathway for autotrophic carbon fixation, but also genes that indicate potential alternative energy metabolisms. Although a bona fide gene for nitrite reductase is missing, the organism is sensitive to NO-scavenging, underlining the potential importance of this compound for AOA metabolism. Ca. N. cavascurensis is distinct from all other AOA in its gene repertoire for replication, cell division and repair. Its genome has an impressive array of mobile genetic elements and other recently acquired gene sets, including conjugative systems, a provirus, transposons and cell appendages. Some of these elements indicate recent exchange with the environment, whereas others seem to have been domesticated and might convey crucial metabolic traits.

Removal of ammonia solutions used in catalytic wet oxidation processes.

Science.gov (United States)

Hung, Chang Mao; Lou, Jie Chung; Lin, Chia Hua

2003-08-01

Ammonia (NH(3)) is an important product used in the chemical industry, and is common place in industrial wastewater. Industrial wastewater containing ammonia is generally either toxic or has concentrations or temperatures such that direct biological treatment is unfeasible. This investigation used aqueous solutions containing more of ammonia for catalytic liquid-phase oxidation in a trickle-bed reactor (TBR) based on Cu/La/Ce composite catalysts, prepared by co-precipitation of Cu(NO(3))(2), La(NO(3))(2), and Ce(NO(3))(3) at 7:2:1 molar concentrations. The experimental results indicated that the ammonia conversion of the wet oxidation in the presence of the Cu/La/Ce composite catalysts was determined by the Cu/La/Ce catalyst. Minimal ammonia was removed from the solution by the wet oxidation in the absence of any catalyst, while approximately 91% ammonia removal was achieved by wet oxidation over the Cu/La/Ce catalyst at 230 degrees C with oxygen partial pressure of 2.0 MPa. Furthermore, the effluent streams were conducted at a liquid hourly space velocity of under 9 h(-1) in the wet catalytic processes, and a reaction pathway was found linking the oxidizing ammonia to nitric oxide, nitrogen and water. The solution contained by-products, including nitrates and nitrites. Nitrite selectivity was minimized and ammonia removal maximized when the feed ammonia solution had a pH of around 12.0.

Expanding diversity of potential bacterial partners of the methanotrophic ANME archaea using Magneto-FISH

Science.gov (United States)

Trembath-Reichert, E.; Green-Saxena, A.; Steele, J. A.; Orphan, V. J.

2012-12-01

Sulfate-coupled anaerobic oxidation of methane (AOM) in marine sediments is the major sink for methane in the oceans. This process is believed to be catalyzed by as yet uncultured syntrophic consortia of ANME archaea (affiliated with the Methanosarcinales) and sulfate-reducing bacteria belonging to the Desulfosarcina/Desulfococcus and Desulfobulbaceae. These syntrophic consortia have been described from methane-rich habitats worldwide and appear to be most concentrated in areas of high methane flux, such as cold seeps along continental margins. The extent of the diversity and ecophysiological potential of these microbial associations is still poorly constrained. In an effort to better characterize the diversity of microorganisms forming associations with different clades of methanotrophic ANME archaea (ANME-1, ANME-2a/b/c, ANME-3) and link these organisms to potentially diagnostic metabolic genes (e.g. mcrA, dsrAB, aprA), we employed a unique culture-independent whole cell capture technique which combines Fluorescence In Situ Hybridization with immuno-magnetic cell capture (Magneto-FISH). We used Magneto-FISH for targeted enrichment of specific ANME groups and their associated bacteria directly from formalin- and ethanol-fixed methane seep sediment. The identity and metabolic gene diversity of captured microorganisms were then assessed by clone library construction and sequencing. Diversity recovered from Magneto-FISH experiments using general and clade-specific ANME targeted probes show both the expected selectivity of the FISH probes (i.e. predominately ANME-2c subclade captured with an ANME-2c probe and multiple ANME groups recovered with the general probe targeting most ANME). Follow up FISH experiments were conducted to confirm physical associations between ANME and unique bacterial members (deltaproteobacteria and other non-sulfate reducing groups) that were common to multiple Magneto-FISH capture experiments. Analyses of metabolic gene diversity for archaeal

Genetic diversity of archaea in deep-sea hydrothermal vent environments.

OpenAIRE

Takai, K; Horikoshi, K

1999-01-01

Molecular phylogenetic analysis of naturally occurring archaeal communities in deep-sea hydrothermal vent environments was carried out by PCR-mediated small subunit rRNA gene (SSU rDNA) sequencing. As determined through partial sequencing of rDNA clones amplified with archaea-specific primers, the archaeal populations in deep-sea hydrothermal vent environments showed a great genetic diversity, and most members of these populations appeared to be uncultivated and unidentified organisms. In the...

Candidatus Nitrosocaldus cavascurensis, an Ammonia Oxidizing, Extremely Thermophilic Archaeon with a Highly Mobile Genome

Directory of Open Access Journals (Sweden)

Sophie S. Abby

2018-01-01

Full Text Available Ammonia oxidizing archaea (AOA of the phylum Thaumarchaeota are widespread in moderate environments but their occurrence and activity has also been demonstrated in hot springs. Here we present the first enrichment of a thermophilic representative with a sequenced genome, which facilitates the search for adaptive strategies and for traits that shape the evolution of Thaumarchaeota. Candidatus Nitrosocaldus cavascurensis has been enriched from a hot spring in Ischia, Italy. It grows optimally at 68°C under chemolithoautotrophic conditions on ammonia or urea converting ammonia stoichiometrically into nitrite with a generation time of approximately 23 h. Phylogenetic analyses based on ribosomal proteins place the organism as a sister group to all known mesophilic AOA. The 1.58 Mb genome of Ca. N. cavascurensis harbors an amoAXCB gene cluster encoding ammonia monooxygenase and genes for a 3-hydroxypropionate/4-hydroxybutyrate pathway for autotrophic carbon fixation, but also genes that indicate potential alternative energy metabolisms. Although a bona fide gene for nitrite reductase is missing, the organism is sensitive to NO-scavenging, underlining the potential importance of this compound for AOA metabolism. Ca. N. cavascurensis is distinct from all other AOA in its gene repertoire for replication, cell division and repair. Its genome has an impressive array of mobile genetic elements and other recently acquired gene sets, including conjugative systems, a provirus, transposons and cell appendages. Some of these elements indicate recent exchange with the environment, whereas others seem to have been domesticated and might convey crucial metabolic traits.

Effects of different fertilizers on the abundance and community structure of ammonia oxidizers in a yellow clay soil.

Science.gov (United States)

Yao, Huaiying; Huang, Sha; Qiu, Qiongfen; Li, Yaying; Wu, Lianghuan; Mi, Wenhai; Dai, Feng

2016-08-01

Yellow clay paddy soil (Oxisols) is a typical soil with low productivity in southern China. Nitrification inhibitors and slow release fertilizers have been used to improve nitrogen fertilizer utilization and reduce environmental impaction of the paddy soil. However, their effects on ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) in paddy soil have rarely been investigated. In the present work, we compared the influences of several slow release fertilizers and nitrification inhibitors on the community structure and activities of the ammonia oxidizers in yellow clay soil. The abundances and community compositions of AOA and AOB were determined with qPCR, terminal restriction fragment length polymorphism (T-RFLP), and clone library approaches. Our results indicated that the potential nitrification rate (PNR) of the soil was significantly related to the abundances of both AOA and AOB. Nitrogen fertilizer application stimulated the growth of AOA and AOB, and the combinations of nitrapyrin with urea (NPU) and urea-formaldehyde (UF) inhibited the growth of AOA and AOB, respectively. Compared with other treatments, the applications of NPU and UF also led to significant shifts in the community compositions of AOA and AOB, respectively. NPU showed an inhibitory effect on AOA T-RF 166 bp that belonged to Nitrosotalea. UF had a negative effect on AOB T-RF 62 bp that was assigned to Nitrosospira. These results suggested that NPU inhibited PNR and increased nitrogen use efficiency (NUE) by inhibiting the growth of AOA and altering AOA community. UF showed no effect on NUE but decreased AOB abundance and shifted AOB community.

Ammonia oxidation at high pressure and intermediate temperatures

DEFF Research Database (Denmark)

Song, Yu; Hashemi, Hamid; Christensen, Jakob Munkholt

2016-01-01

Ammonia oxidation experiments were conducted at high pressure (30 bar and 100 bar) under oxidizing and stoichiometric conditions, respectively, and temperatures ranging from 450 to 925 K. The oxidation of ammonia was slow under stoichiometric conditions in the temperature range investigated. Under...... oxidizing conditions the onset temperature for reaction was 850–875 K at 30 bar, while at 100 bar it was about 800 K, with complete consumption of NH3 at 875 K. The products of reaction were N2 and N2O, while NO and NO2 concentrations were below the detection limit even under oxidizing conditions. The data...... was satisfactory. The main oxidation path for NH3 at high pressure under oxidizing conditions is NH3⟶+OH NH2⟶+HO2,NO2 H2NO⟶+O2 HNO⟶+O2 NO ⟶+NH2 N2. The modeling predictions are most sensitive to the reactions NH2 + NO = NNH + OH and NH2 + HO2 = H2NO + OH, which promote the ammonia consumption by forming OH...

Biogeochemical evidence that thermophilic Archaea mediate the anaerobic oxidation of methane

NARCIS (Netherlands)

Sinninghe Damsté, J.S.; Schouten, S.; Wakeham, S.G.; Hopmans, E.C.

2003-01-01

Distributions and isotopic analyses of lipids from sediment cores at a hydrothermally active site in the Guaymas Basin with a steep sedimentary temperature gradient revealed the presence of archaea that oxidize methane anaerobically. The presence of strongly 13C-depleted lipids at greater depths in

Ammonia- and Nitrite-Oxidizing Bacterial Communities in a Pilot-Scale Chloraminated Drinking Water Distribution System

OpenAIRE

Regan, John M.; Harrington, Gregory W.; Noguera, Daniel R.

2002-01-01

Nitrification in drinking water distribution systems is a common operational problem for many utilities that use chloramines for secondary disinfection. The diversity of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) in the distribution systems of a pilot-scale chloraminated drinking water treatment system was characterized using terminal restriction fragment length polymorphism (T-RFLP) analysis and 16S rRNA gene (ribosomal DNA [rDNA]) cloning and sequencing. For ammon...

SOIL NITROUS OXIDE, NITRIC OXIDE, AND AMMONIA EMISSIONS FROM A RECOVERING RIPARIAN ECOSYSTEM IN SOUTHERN APPALACHIA

Science.gov (United States)

The paper presents two years of seasonal nitric oxide, ammonia, and nitrous oxide trace gas fluxes measured in a recovering riparian zone with cattle excluded and in an adjacent riparian zone grazed by cattle. In the recovering riparian zone, average nitric oxide, ammonia, and ni...

Catalytic wet oxidation of ammonia solution: Activity of the nanoscale platinum-palladium-rhodium composite oxide catalyst

International Nuclear Information System (INIS)

Hung, C.-M.

2009-01-01

Aqueous solutions of 400-1000 mg/L of ammonia were oxidized in a trickle-bed reactor (TBR) in this study of nanoscale platinum-palladium-rhodium composite oxide catalysts, which were prepared by the co-precipitation of H 2 PtCl 6 , Pd(NO 3 ) 3 and Rh(NO 3 ) 3 . Hardly any of the dissolved ammonia was removed by wet oxidation in the absence of any catalyst, whereas about 99% of the ammonia was reduced during wet oxidation over nanoscale platinum-palladium-rhodium composite oxide catalysts at 503 K in an oxygen partial pressure of 2.0 MPa. A synergistic effect exists in the nanoscale platinum-palladium-rhodium composite structure, which is the material with the highest ammonia reduction activity. The nanometer-sized particles were characterized by TEM, XRD and FTIR. The effect of the initial concentration and reaction temperature on the removal of ammonia from the effluent streams was also studied at a liquid hourly space velocity of under 9 h -1 in the wet catalytic processes

Catalytic wet oxidation of ammonia solution: Activity of the nanoscale platinum-palladium-rhodium composite oxide catalyst

Energy Technology Data Exchange (ETDEWEB)

Hung, C.-M. [Department of Industry Engineering and Management, Yung-Ta Institute of Technology and Commerce, 316 Chung-shan Road, Linlo, Pingtung 909, Taiwan (China)], E-mail: hungcm1031@gmail.com

2009-04-15

Aqueous solutions of 400-1000 mg/L of ammonia were oxidized in a trickle-bed reactor (TBR) in this study of nanoscale platinum-palladium-rhodium composite oxide catalysts, which were prepared by the co-precipitation of H{sub 2}PtCl{sub 6}, Pd(NO{sub 3}){sub 3} and Rh(NO{sub 3}){sub 3}. Hardly any of the dissolved ammonia was removed by wet oxidation in the absence of any catalyst, whereas about 99% of the ammonia was reduced during wet oxidation over nanoscale platinum-palladium-rhodium composite oxide catalysts at 503 K in an oxygen partial pressure of 2.0 MPa. A synergistic effect exists in the nanoscale platinum-palladium-rhodium composite structure, which is the material with the highest ammonia reduction activity. The nanometer-sized particles were characterized by TEM, XRD and FTIR. The effect of the initial concentration and reaction temperature on the removal of ammonia from the effluent streams was also studied at a liquid hourly space velocity of under 9 h{sup -1} in the wet catalytic processes.

Catalytic wet oxidation of ammonia solution: activity of the nanoscale platinum-palladium-rhodium composite oxide catalyst.

Science.gov (United States)

Hung, Chang-Mao

2009-04-15

Aqueous solutions of 400-1000 mg/L of ammonia were oxidized in a trickle-bed reactor (TBR) in this study of nanoscale platinum-palladium-rhodium composite oxide catalysts, which were prepared by the co-precipitation of H(2)PtCl(6), Pd(NO(3))(3) and Rh(NO(3))(3). Hardly any of the dissolved ammonia was removed by wet oxidation in the absence of any catalyst, whereas about 99% of the ammonia was reduced during wet oxidation over nanoscale platinum-palladium-rhodium composite oxide catalysts at 503 K in an oxygen partial pressure of 2.0 MPa. A synergistic effect exists in the nanoscale platinum-palladium-rhodium composite structure, which is the material with the highest ammonia reduction activity. The nanometer-sized particles were characterized by TEM, XRD and FTIR. The effect of the initial concentration and reaction temperature on the removal of ammonia from the effluent streams was also studied at a liquid hourly space velocity of under 9 h(-1) in the wet catalytic processes.

Communities of archaea and bacteria in a subsurface radioactive thermal spring in the Austrian Central Alps, and evidence of ammonia-oxidizing Crenarchaeota.

Science.gov (United States)

Weidler, Gerhard W; Dornmayr-Pfaffenhuemer, Marion; Gerbl, Friedrich W; Heinen, Wolfgang; Stan-Lotter, Helga

2007-01-01

Scanning electron microscopy revealed great morphological diversity in biofilms from several largely unexplored subterranean thermal Alpine springs, which contain radium 226 and radon 222. A culture-independent molecular analysis of microbial communities on rocks and in the water of one spring, the "Franz-Josef-Quelle" in Bad Gastein, Austria, was performed. Four hundred fifteen clones were analyzed. One hundred thirty-two sequences were affiliated with 14 bacterial operational taxonomic units (OTUs) and 283 with four archaeal OTUs. Rarefaction analysis indicated a high diversity of bacterial sequences, while archaeal sequences were less diverse. The majority of the cloned archaeal 16S rRNA gene sequences belonged to the soil-freshwater-subsurface (1.1b) crenarchaeotic group; other representatives belonged to the freshwater-wastewater-soil (1.3b) group, except one clone, which was related to a group of uncultivated Euryarchaeota. These findings support recent reports that Crenarchaeota are not restricted to high-temperature environments. Most of the bacterial sequences were related to the Proteobacteria (alpha, beta, gamma, and delta), Bacteroidetes, and Planctomycetes. One OTU was allied with Nitrospina sp. (delta-Proteobacteria) and three others grouped with Nitrospira. Statistical analyses suggested high diversity based on 16S rRNA gene analyses; the rarefaction plot of archaeal clones showed a plateau. Since Crenarchaeota have been implicated recently in the nitrogen cycle, the spring environment was probed for the presence of the ammonia monooxygenase subunit A (amoA) gene. Sequences were obtained which were related to crenarchaeotic amoA genes from marine and soil habitats. The data suggested that nitrification processes are occurring in the subterranean environment and that ammonia may possibly be an energy source for the resident communities.

Comparative diversity of ammonia oxidizer 16S rRNA gene sequences in native, tilled, and successional soils

NARCIS (Netherlands)

Bruns, M.A.; Stephen, J.R.; Kowalchuk, G.A.; Prosser, J.I.; Paul, E.A.

1999-01-01

Autotrophic ammonia oxidizer (AAO) populations in soils from native, tilled, and successional treatments at the Kellogg Biological Station Long-Term Ecological Research site in southwestern Michigan were compared to assess effects of disturbance on these bacteria. N fertilization effects on AAO

Amperometric detection and electrochemical oxidation of aliphatic amines and ammonia on silver-lead oxide thin-film electrodes

Energy Technology Data Exchange (ETDEWEB)

Ge, Jisheng [Iowa State Univ., Ames, IA (United States)

1996-01-08

This thesis comprises three parts: Electrocatalysis of anodic oxygen-transfer reactions: aliphatic amines at mixed Ag-Pb oxide thin-film electrodes; oxidation of ammonia at anodized Ag-Pb eutectic alloy electrodes; and temperature effects on oxidation of ethylamine, alanine, and aquated ammonia.

Application of hierarchical oligonucleotide primer extension (HOPE) to assess relative abundances of ammonia- and nitrite-oxidizing bacteria

KAUST Repository

Scarascia, Giantommaso

2017-04-04

Background: Establishing an optimal proportion of nitrifying microbial populations, including ammonia-oxidizing bacteria (AOB), nitrite-oxidizing bacteria (NOB), complete nitrite oxidizers (comammox) and ammonia-oxidizing archaea (AOA), is important for ensuring the efficiency of nitrification in water treatment systems. Hierarchical oligonucleotide primer extension (HOPE), previously developed to rapidly quantify relative abundances of specific microbial groups of interest, was applied in this study to track the abundances of the important nitrifying bacterial populations. Results: The method was tested against biomass obtained from a laboratory-scale biofilm-based trickling reactor, and the findings were validated against those obtained by 16S rRNA gene-based amplicon sequencing. Our findings indicated a good correlation between the relative abundance of nitrifying bacterial populations obtained using both HOPE and amplicon sequencing. HOPE showed a significant increase in the relative abundance of AOB, specifically Nitrosomonas, with increasing ammonium content and shock loading (p < 0.001). In contrast, Nitrosospira remained stable in its relative abundance against the total community throughout the operational phases. There was a corresponding significant decrease in the relative abundance of NOB, specifically Nitrospira and those affiliated to comammox, during the shock loading. Based on the relative abundance of AOB and NOB (including commamox) obtained from HOPE, it was determined that the optimal ratio of AOB against NOB ranged from 0.2 to 2.5 during stable reactor performance. Conclusions: Overall, the HOPE method was developed and validated against 16S rRNA gene-based amplicon sequencing for the purpose of performing simultaneous monitoring of relative abundance of nitrifying populations. Quantitative measurements of these nitrifying populations obtained via HOPE would be indicative of reactor performance and nitrification functionality.

Bioprospecting Archaea: Focus on Extreme Halophiles

KAUST Repository

Antunes, André

2016-12-12

In 1990, Woese et al. divided the Tree of Life into three separate domains: Eukarya, Bacteria, and Archaea. Archaea were originally perceived as little more than “odd bacteria” restricted to extreme environmental niches, but later discoveries challenged this assumption. Members of this domain populate a variety of unexpected environments (e.g. soils, seawater, and human bodies), and we currently witness ongoing massive expansions of the archaeal branch of the Tree of Life. Archaea are now recognized as major players in the biosphere and constitute a significant fraction of the earth’s biomass, yet they remain underexplored. An ongoing surge in exploration efforts is leading to an increase in the (a) number of isolated strains, (b) associated knowledge, and (c) utilization of Archaea in biotechnology. They are increasingly employed in fields as diverse as biocatalysis, biocomputing, bioplastic production, bioremediation, bioengineering, food, pharmaceuticals, and nutraceuticals. This chapter provides a general overview on bioprospecting Archaea, with a particular focus on extreme halophiles. We explore aspects such as diversity, ecology, screening techniques and biotechnology. Current and future trends in mining for applications are discussed.

Ammonia- and nitrite-oxidizing bacterial communities in a pilot-scale chloraminated drinking water distribution system.

Science.gov (United States)

Regan, John M; Harrington, Gregory W; Noguera, Daniel R

2002-01-01

Nitrification in drinking water distribution systems is a common operational problem for many utilities that use chloramines for secondary disinfection. The diversity of ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) in the distribution systems of a pilot-scale chloraminated drinking water treatment system was characterized using terminal restriction fragment length polymorphism (T-RFLP) analysis and 16S rRNA gene (ribosomal DNA [rDNA]) cloning and sequencing. For ammonia oxidizers, 16S rDNA-targeted T-RFLP indicated the presence of Nitrosomonas in each of the distribution systems, with a considerably smaller peak attributable to Nitrosospira-like AOB. Sequences of AOB amplification products aligned within the Nitrosomonas oligotropha cluster and were closely related to N. oligotropha and Nitrosomonas ureae. The nitrite-oxidizing communities were comprised primarily of Nitrospira, although Nitrobacter was detected in some samples. These results suggest a possible selection of AOB related to N. oligotropha and N. ureae in chloraminated systems and demonstrate the presence of NOB, indicating a biological mechanism for nitrite loss that contributes to a reduction in nitrite-associated chloramine decay.

Diversity of bacteria and archaea from two shallow marine hydrothermal vents from Vulcano Island.

Science.gov (United States)

Antranikian, Garabed; Suleiman, Marcel; Schäfers, Christian; Adams, Michael W W; Bartolucci, Simonetta; Blamey, Jenny M; Birkeland, Nils-Kåre; Bonch-Osmolovskaya, Elizaveta; da Costa, Milton S; Cowan, Don; Danson, Michael; Forterre, Patrick; Kelly, Robert; Ishino, Yoshizumi; Littlechild, Jennifer; Moracci, Marco; Noll, Kenneth; Oshima, Tairo; Robb, Frank; Rossi, Mosè; Santos, Helena; Schönheit, Peter; Sterner, Reinhard; Thauer, Rudolf; Thomm, Michael; Wiegel, Jürgen; Stetter, Karl Otto

2017-07-01

To obtain new insights into community compositions of hyperthermophilic microorganisms, defined as having optimal growth temperatures of 80 °C and above, sediment and water samples were taken from two shallow marine hydrothermal vents (I and II) with temperatures of 100 °C at Vulcano Island, Italy. A combinatorial approach of denaturant gradient gel electrophoresis (DGGE) and metagenomic sequencing was used for microbial community analyses of the samples. In addition, enrichment cultures, growing anaerobically on selected polysaccharides such as starch and cellulose, were also analyzed by the combinatorial approach. Our results showed a high abundance of hyperthermophilic archaea, especially in sample II, and a comparable diverse archaeal community composition in both samples. In particular, the strains of the hyperthermophilic anaerobic genera Staphylothermus and Thermococcus, and strains of the aerobic hyperthermophilic genus Aeropyrum, were abundant. Regarding the bacterial community, ε-Proteobacteria, especially the genera Sulfurimonas and Sulfurovum, were highly abundant. The microbial diversity of the enrichment cultures changed significantly by showing a high dominance of archaea, particularly the genera Thermococcus and Palaeococcus, depending on the carbon source and the selected temperature.

Revisiting the electrochemical oxidation of ammonia on carbon-supported metal nanoparticle catalysts

International Nuclear Information System (INIS)

Li, Zhe-Fei; Wang, Yuxuan; Botte, Gerardine G.

2017-01-01

Highlights: • A procedure to pretreat electrocatalysts to study the ammonia oxidation is provided. • N ads and O/OH ads were identified as the major deactivation species that prevent ammonia oxidatoin. • The electrocatalytic activity, thermodynamics, and possible deactivation mechanisms for ammonia oxidation were elucidated. • The onset potential for ammonia oxidation is related to the hydrogen binding energy of the catalyst. • Ammonia electro-oxidation involves a complex decoupled electron and proton transfer process. - Abstract: The ammonia electro-oxidation reaction (AOR) has been studied due to its promising applications in ammonia electrolysis, wastewater remediation, direct ammonia fuel cells, and sensors. However, it is difficult to compare and analyze the reported electrocatalytic activity of AOR reliably, likely due to the variation in catalyst synthesis, electrode composition, electrode morphology, and testing protocol. In this paper, the electro-oxidation of ammonia on different carbon-supported precious metal nanoparticle catalysts was revisited. The effect of experimental conditions, electrochemical test parameters, electrocatalytic activity, thermodynamics, and possible deactivation mechanism of the catalysts were investigated. Pt/C catalyst possesses the highest electrocatalytic activity, while Ir/C and Rh/C show lower overpotential. The onset potential of the AOR is related to the hydrogen binding energy of the catalyst. N ads is one major cause of deactivation accompanied with the formation of surface O/OH ads at high potentials. The coulombic efficiency of N ads formation on Pt is about 1% initially and gradually decreases with reaction time. Increase in ammonia concentration leads to increase in current density, while increase in hydroxyl ions concentration can enhance the current density and reduce the overpotential simultaneously. The slopes of AOR onset potential and hydrogen adsorption/desorption potential of Pt/C as a function of p

Controls of nitrite oxidation in ammonia-removing biological air filters

DEFF Research Database (Denmark)

Juhler, Susanne; Ottosen, Lars Ditlev Mørck; Nielsen, Lars Peter

2008-01-01

in accumulation of nitrate rather than nitrite and a significant decline in pH. As a consequence, ammonia is removed more efficiently, but heterotrophic oxidation of odorous compounds might be inhibited.  To identify the controlling mechanisms of nitrite oxidation, full-scale biological air filters were...... activity resulting in a lowered pH and thus a decreased FA concentration, promoting further growth of NOB. Yet, in some cases a situation with a nitrate-to-nitrite ratio of 1 and moderate pH remained stable even under varying air load and water supply, suggesting that additional mechanisms were involved......In biological air filters ammonia is removed due to the action of Ammonia Oxidizing Bacteria (AOB) resulting in nitrite accumulation exceeding 100 mM. Among filters treating exhaust air from pig facilities successful establishment of Nitrite Oxidizing Bacteria (NOB) sometimes occurs, resulting...

Bioturbation determines the response of benthic ammonia-oxidizing microorganisms to ocean acidification

Science.gov (United States)

Laverock, B.; Kitidis, V.; Tait, K.; Gilbert, J. A.; Osborn, A. M.; Widdicombe, S.

2013-01-01

Ocean acidification (OA), caused by the dissolution of increasing concentrations of atmospheric carbon dioxide (CO2) in seawater, is projected to cause significant changes to marine ecology and biogeochemistry. Potential impacts on the microbially driven cycling of nitrogen are of particular concern. Specifically, under seawater pH levels approximating future OA scenarios, rates of ammonia oxidation (the rate-limiting first step of the nitrification pathway) have been shown to dramatically decrease in seawater, but not in underlying sediments. However, no prior study has considered the interactive effects of microbial ammonia oxidation and macrofaunal bioturbation activity, which can enhance nitrogen transformation rates. Using experimental mesocosms, we investigated the responses to OA of ammonia oxidizing microorganisms inhabiting surface sediments and sediments within burrow walls of the mud shrimp Upogebia deltaura. Seawater was acidified to one of four target pH values (pHT 7.90, 7.70, 7.35 and 6.80) in comparison with a control (pHT 8.10). At pHT 8.10, ammonia oxidation rates in burrow wall sediments were, on average, fivefold greater than in surface sediments. However, at all acidified pH values (pH ≤ 7.90), ammonia oxidation rates in burrow sediments were significantly inhibited (by 79–97%; p < 0.01), whereas rates in surface sediments were unaffected. Both bacterial and archaeal abundances increased significantly as pHT declined; by contrast, relative abundances of bacterial and archaeal ammonia oxidation (amoA) genes did not vary. This research suggests that OA could cause substantial reductions in total benthic ammonia oxidation rates in coastal bioturbated sediments, leading to corresponding changes in coupled nitrogen cycling between the benthic and pelagic realms. PMID:23980243

First Insights into the Diverse Human Archaeome: Specific Detection of Archaea in the Gastrointestinal Tract, Lung, and Nose and on Skin

Directory of Open Access Journals (Sweden)

Kaisa Koskinen

2017-11-01

Full Text Available Human-associated archaea remain understudied in the field of microbiome research, although in particular methanogenic archaea were found to be regular commensals of the human gut, where they represent keystone species in metabolic processes. Knowledge on the abundance and diversity of human-associated archaea is extremely limited, and little is known about their function(s, their overall role in human health, or their association with parts of the human body other than the gastrointestinal tract and oral cavity. Currently, methodological issues impede the full assessment of the human archaeome, as bacteria-targeting protocols are unsuitable for characterization of the full spectrum of Archaea. The goal of this study was to establish conservative protocols based on specifically archaea-targeting, PCR-based methods to retrieve first insights into the archaeomes of the human gastrointestinal tract, lung, nose, and skin. Detection of Archaea was highly dependent on primer selection and the sequence processing pipeline used. Our results enabled us to retrieve a novel picture of the human archaeome, as we found for the first time Methanobacterium and Woesearchaeota (DPANN superphylum to be associated with the human gastrointestinal tract and the human lung, respectively. Similar to bacteria, human-associated archaeal communities were found to group biogeographically, forming (i the thaumarchaeal skin landscape, (ii the (methanoeuryarchaeal gastrointestinal tract, (iii a mixed skin-gastrointestinal tract landscape for the nose, and (iv a woesearchaeal lung landscape. On the basis of the protocols we used, we were able to detect unexpectedly high diversity of archaea associated with different body parts.

Ammonia release method for depositing metal oxides

Energy Technology Data Exchange (ETDEWEB)

Silver, G.L.; Martin, F.S.

1993-12-31

A method of depositing metal oxides on substrates which is indifferent to the electrochemical properties of the substrates and which comprises forming ammine complexes containing metal ions and thereafter effecting removal of ammonia from the ammine complexes so as to permit slow precipitation and deposition of metal oxide on the substrates.

Effect of nutrient and selective inhibitor amendments on methane oxidation, nitrous oxide production, and key gene presence and expression in landfill cover soils: characterization of the role of methanotrophs, nitrifiers, and denitrifiers.

Science.gov (United States)

Lee, Sung-Woo; Im, Jeongdae; Dispirito, Alan A; Bodrossy, Levente; Barcelona, Michael J; Semrau, Jeremy D

2009-11-01

Methane and nitrous oxide are both potent greenhouse gasses, with global warming potentials approximately 25 and 298 times that of carbon dioxide. A matrix of soil microcosms was constructed with landfill cover soils collected from the King Highway Landfill in Kalamazoo, Michigan and exposed to geochemical parameters known to affect methane consumption by methanotrophs while also examining their impact on biogenic nitrous oxide production. It was found that relatively dry soils (5% moisture content) along with 15 mg NH (4) (+) (kg soil)(-1) and 0.1 mg phenylacetylene(kg soil)(-1) provided the greatest stimulation of methane oxidation while minimizing nitrous oxide production. Microarray analyses of pmoA showed that the methanotrophic community structure was dominated by Type II organisms, but Type I genera were more evident with the addition of ammonia. When phenylacetylene was added in conjunction with ammonia, the methanotrophic community structure was more similar to that observed in the presence of no amendments. PCR analyses showed the presence of amoA from both ammonia-oxidizing bacteria and archaea, and that the presence of key genes associated with these cells was reduced with the addition of phenylacetylene. Messenger RNA analyses found transcripts of pmoA, but not of mmoX, nirK, norB, or amoA from either ammonia-oxidizing bacteria or archaea. Pure culture analyses showed that methanotrophs could produce significant amounts of nitrous oxide, particularly when expressing the particulate methane monooxygenase (pMMO). Collectively, these data suggest that methanotrophs expressing pMMO played a role in nitrous oxide production in these microcosms.

Diversity of halophilic archaea from six hypersaline environments in Turkey.

Science.gov (United States)

Ozcan, Birgul; Ozcengiz, Gulay; Coleri, Arzu; Cokmus, Cumhur

2007-06-01

The diversity of archaeal strains from six hypersaline environments in Turkey was analyzed by comparing their phenotypic characteristics and 16S rDNA sequences. Thirty-three isolates were characterized in terms of their phenotypic properties including morphological and biochemical characteristics, susceptibility to different antibiotics, and total lipid and plasmid contents, and finally compared by 16S rDNA gene sequences. The results showed that all isolates belong to the family Halobacteriaceae. Phylogenetic analyses using approximately 1,388 bp comparisions of 16S rDNA sequences demonstrated that all isolates clustered closely to species belonging to 9 genera, namely Halorubrum (8 isolates), Natrinema (5 isolates), Haloarcula (4 isolates), Natronococcus (4 isolates), Natrialba (4 isolates), Haloferax (3 isolates), Haloterrigena (3 isolates), Halalkalicoccus (1 isolate), and Halomicrobium (1 isolate). The results revealed a high diversity among the isolated halophilic strains and indicated that some of these strains constitute new taxa of extremely halophilic archaea.

2011 Archaea: Ecology, Metabolism, & Molecular Biology

Energy Technology Data Exchange (ETDEWEB)

Keneth Stedman

2011-08-05

Archaea, one of three major evolutionary lineages of life, are a fascinating and diverse group of microbes with deep roots overlapping those of eukaryotes. The focus of the 'Archaea: Ecology Metabolism & Molecular Biology' GRC conference expands on a number of emerging topics highlighting new paradigms in archaeal metabolism, genome function and systems biology; information processing; evolution and the tree of life; the ecology and diversity of archaea and their viruses. The strength of this conference lies in its ability to couple a field with a rich history in high quality research with new scientific findings in an atmosphere of stimulating exchange. This conference remains an excellent opportunity for younger scientists to interact with world experts in this field.

Application of a novel functional gene microarray to probe the functional ecology of ammonia oxidation in nitrifying activated sludge.

Directory of Open Access Journals (Sweden)

Michael D Short

Full Text Available We report on the first study trialling a newly-developed, functional gene microarray (FGA for characterising bacterial and archaeal ammonia oxidisers in activated sludge. Mixed liquor (ML and media biofilm samples from a full-scale integrated fixed-film activated sludge (IFAS plant were analysed with the FGA to profile the diversity and relative abundance of ammonia-oxidising archaea and bacteria (AOA and AOB respectively. FGA analyses of AOA and AOB communities revealed ubiquitous distribution of AOA across all samples - an important finding for these newly-discovered and poorly characterised organisms. Results also revealed striking differences in the functional ecology of attached versus suspended communities within the IFAS reactor. Quantitative assessment of AOB and AOA functional gene abundance revealed a dominance of AOB in the ML and approximately equal distribution of AOA and AOB in the media-attached biofilm. Subsequent correlations of functional gene abundance data with key water quality parameters suggested an important functional role for media-attached AOB in particular for IFAS reactor nitrification performance and indicate possible functional redundancy in some IFAS ammonia oxidiser communities. Results from this investigation demonstrate the capacity of the FGA to resolve subtle ecological shifts in key microbial communities in nitrifying activated sludge and indicate its value as a tool for better understanding the linkages between the ecology and performance of these engineered systems.

Inhibition of Direct Electrolytic Ammonia Oxidation Due to a Change in Local pH

International Nuclear Information System (INIS)

Zöllig, Hanspeter; Morgenroth, Eberhard; Udert, Kai M.

2015-01-01

Electrochemical ammonia oxidation has gained a lot of attention recently as an efficient method for ammonia removal from wastewater, for the use in ammonia-based fuel cells and the production of high purity hydrogen. Thermally decomposed iridium oxide films (TDIROF) have been shown to be catalytically active for direct ammonia oxidation in aqueous solutions if NH 3 is present. However, the process was reported to be rapidly inhibited on TDIROF. Herein, we show that this fast inhibition of direct ammonia oxidation does not result from surface poisoning by adsorbed elemental nitrogen (N ads ). Instead, we propose that direct ammonia oxidation and oxygen evolution can lead to a drop of the local pH at the electrode resulting in a low availability of the actual reactant, NH 3 . The hypothesis was tested with cyclic voltammetry (CV) experiments on stagnant and rotating disk electrodes (RDE). The CV experiments on the stagnant electrode revealed that the decrease of the ammonia oxidation peaks was considerably reduced by introducing an idle phase at open circuit potential between subsequent scans. Furthermore, the polarization of the TDIROF electrode into the hydrogen evolution region (HER) resulted in increased ammonia oxidation peaks in the following anodic scans which can be explained with an increased local pH after the consumption of protons in the HER. On the RDE, the ammonia oxidation peaks did not decrease in immediately consecutive scans. These findings would not be expected if surface poisoning was responsible for the fast inhibition but they are in good agreement with the proposed mechanism of pH induced limitation by the reactant, NH 3 . The plausibility of the mechanism was also supported by our numerical simulations of the processes in the Nernstian diffusion layer. The knowledge about this inhibition mechanism of direct ammonia oxidation is especially important for the design of electrochemical cells for wastewater treatment. The mechanism is not only

Anodic ammonia oxidation to nitrogen gas catalyzed by mixed biofilms in bioelectrochemical systems

International Nuclear Information System (INIS)

Zhan, Guoqiang; Zhang, Lixia; Tao, Yong; Wang, Yujian; Zhu, Xiaoyu; Li, Daping

2014-01-01

In this paper we report ammonia oxidation to nitrogen gas using microbes as biocatalyst on the anode, with polarized electrode (+600 mV vs. Ag/AgCl) as electron acceptor. In batch experiments, the maximal rate of ammonia-N oxidation by the mixed culture was ∼ 60 mg L −1 d −1 , and nitrogen gas was the main products in anode compartment. Cyclic voltammetry for testing the electroactivity of the anodic biofilms revealed that an oxidation peak appeared at +600 mV (vs. Ag/AgCl), whereas the electrode without biofilms didn’t appear oxidation peak, indicating that the bioanode had good electroactivities for ammonia oxidation. Microbial community analysis of 16S rRNA genes based on high throughput sequencing indicated that the combination of the dominant genera of Nitrosomonas, Comamonas and Paracocus could be important for the electron transfer from ammonia oxidation to anode

Diversity of methanogenic archaea in freshwater sediments of lacustrine ecosystems.

Science.gov (United States)

Laskar, Folguni; Das Purkayastha, Sumi; Sen, Aniruddha; Bhattacharya, Mrinal K; Misra, Biswapriya B

2018-02-01

About half of the global methane (CH 4 ) emission is contributed by the methanogenic archaeal communities leading to a significant increase in global warming. This unprecedented situation has increased the ever growing necessity of evaluating the control measures for limiting CH 4 emission to the atmosphere. Unfortunately, research endeavors on the diversity and functional interactions of methanogens are not extensive till date. We anticipate that the study of the diversity of methanogenic community is paramount for understanding the metabolic processes in freshwater lake ecosystems. Although there are several disadvantages of conventional culture-based methods for determining the diversity of methanogenic archaeal communities, in order to understand their ecological roles in natural environments it is required to culture the microbes. Recently different molecular techniques have been developed for determining the structure of methanogenic archaeal communities thriving in freshwater lake ecosystem. The two gene based cloning techniques required for this purpose are 16S rRNA and methyl coenzyme M reductase (mcrA) in addition to the recently developed metagenomics approaches and high throughput next generation sequencing efforts. This review discusses the various methods of culture-dependent and -independent measures of determining the diversity of methanogen communities in lake sediments in lieu of the different molecular approaches and inter-relationships of diversity of methanogenic archaea. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Diversity of the DNA Replication System in the Archaea Domain

Directory of Open Access Journals (Sweden)

Felipe Sarmiento

2014-01-01

Full Text Available The precise and timely duplication of the genome is essential for cellular life. It is achieved by DNA replication, a complex process that is conserved among the three domains of life. Even though the cellular structure of archaea closely resembles that of bacteria, the information processing machinery of archaea is evolutionarily more closely related to the eukaryotic system, especially for the proteins involved in the DNA replication process. While the general DNA replication mechanism is conserved among the different domains of life, modifications in functionality and in some of the specialized replication proteins are observed. Indeed, Archaea possess specific features unique to this domain. Moreover, even though the general pattern of the replicative system is the same in all archaea, a great deal of variation exists between specific groups.

Activity of Cu-activated carbon fiber catalyst in wet oxidation of ammonia solution.

Science.gov (United States)

Hung, Chang-Mao

2009-07-30

Aqueous solutions of 200-1000 mg/L of ammonia were oxidized in a trickle-bed reactor using Cu-activated carbon fiber (ACF) catalysts, which were prepared by incipient wet impregnation with aqueous solutions of copper nitrate that was deposited on ACF substrates. The results reveal that the conversion of ammonia by wet oxidation in the presence of Cu-ACF catalysts was a function of the metal loading weight ratio of the catalyst. The total conversion efficiency of ammonia was 95% during wet oxidation over the catalyst at 463 K at an oxygen partial pressure of 3.0 MPa. Moreover, the effect of the initial concentration of ammonia and the reaction temperature on the removal of ammonia from the effluent streams was also studied at a liquid space velocity of less than 3.0 h(-1).

Activity of Cu-activated carbon fiber catalyst in wet oxidation of ammonia solution

International Nuclear Information System (INIS)

Hung, Chang-Mao

2009-01-01

Aqueous solutions of 200-1000 mg/L of ammonia were oxidized in a trickle-bed reactor using Cu-activated carbon fiber (ACF) catalysts, which were prepared by incipient wet impregnation with aqueous solutions of copper nitrate that was deposited on ACF substrates. The results reveal that the conversion of ammonia by wet oxidation in the presence of Cu-ACF catalysts was a function of the metal loading weight ratio of the catalyst. The total conversion efficiency of ammonia was 95% during wet oxidation over the catalyst at 463 K at an oxygen partial pressure of 3.0 MPa. Moreover, the effect of the initial concentration of ammonia and the reaction temperature on the removal of ammonia from the effluent streams was also studied at a liquid space velocity of less than 3.0 h -1 .

Environmental evaluation of coexistence of denitrifying anaerobic methane-oxidizing archaea and bacteria in a paddy field.

Science.gov (United States)

Ding, Jing; Fu, Liang; Ding, Zhao-Wei; Lu, Yong-Ze; Cheng, Shuk H; Zeng, Raymond J

2016-01-01

The nitrate-dependent denitrifying anaerobic methane oxidation (DAMO) process, which is metabolized together by anaerobic methanotrophic archaea and NC10 phylum bacteria, is expected to be important for the global carbon and nitrogen cycles. However, there are little studies about the existence of this process and the functional microbes in environments. Therefore, the coexistence of DAMO archaea and bacteria in a paddy field was evaluated in this study. Next-generation sequencing showed that the two orders, Methanosarcinales and Nitrospirales, to which DAMO archaea and DAMO bacteria belong, were detected in the four soil samples. Then the in vitro experiments demonstrated both of nitrite- and nitrate-dependent DAMO activities, which confirmed the coexistence of DAMO archaea and DAMO bacteria. It was the first report about the coexistence of DAMO archaea and bacteria in a paddy field. Furthermore, anammox bacteria were detected in two of the four samples. The in vitro experiments did not show anammox activity in the initial period but showed low anammox activity after 20 days' enrichment. These results implicated that anammox bacteria may coexist with DAMO microorganisms in this field, but at a very low percentage.

The inhibitory effects of free ammonia on ammonia oxidizing bacteria and nitrite oxidizing bacteria under anaerobic condition.

Science.gov (United States)

Qian, Wenting; Peng, Yongzhen; Li, Xiyao; Zhang, Qiong; Ma, Bin

2017-11-01

The free ammonia (FA) inhibition on ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB) under anaerobic condition was investigated in this study. The results indicated that NOB was more sensitive to the FA anaerobic treatment than AOB. The FA anaerobic inhibition on nitrifier gradually heightened with the increase of FA concentration. Accompanied with FA concentration increase from 0 to 16.82mgNH 3 -N·L -1 (the highest concentration adopted in this study), the activity of AOB reduced by 15.9%, while NOB decreased by 29.2%. After FA anaerobic treatment, nitrite was accumulated during nitrification. However, the nitrite accumulation disappeared on the sixth cycle of activity recovery tests with excessive aeration. Based on this result, a novel strategy for achieving nitritation is proposed, which involves recirculating a portion of the activated sludge through a side-line sludge treatment unit, where the sludge is subjected to treatment with FA under anaerobic condition. Copyright © 2017 Elsevier Ltd. All rights reserved.

Activity of Cu-activated carbon fiber catalyst in wet oxidation of ammonia solution

Energy Technology Data Exchange (ETDEWEB)

Hung, Chang-Mao, E-mail: hungcm1031@gmail.com [Department of Industry Engineering and Management, Yung-Ta Institute of Technology and Commerce, 316 Chung-shan Road, Linlo, Pingtung 909, Taiwan (China)

2009-07-30

Aqueous solutions of 200-1000 mg/L of ammonia were oxidized in a trickle-bed reactor using Cu-activated carbon fiber (ACF) catalysts, which were prepared by incipient wet impregnation with aqueous solutions of copper nitrate that was deposited on ACF substrates. The results reveal that the conversion of ammonia by wet oxidation in the presence of Cu-ACF catalysts was a function of the metal loading weight ratio of the catalyst. The total conversion efficiency of ammonia was 95% during wet oxidation over the catalyst at 463 K at an oxygen partial pressure of 3.0 MPa. Moreover, the effect of the initial concentration of ammonia and the reaction temperature on the removal of ammonia from the effluent streams was also studied at a liquid space velocity of less than 3.0 h{sup -1}.

Detection by denaturing gradient gel electrophoresis of ammonia-oxidizing bacteria in microcosms of crude oil-contaminated mangrove sediments.

Science.gov (United States)

dos Santos, A C F; Marques, E L S; Gross, E; Souza, S S; Dias, J C T; Brendel, M; Rezende, R P

2012-01-27

Currently, the effect of crude oil on ammonia-oxidizing bacterium communities from mangrove sediments is little understood. We studied the diversity of ammonia-oxidizing bacteria in mangrove microcosm experiments using mangrove sediments contaminated with 0.1, 0.5, 1, 2, and 5% crude oil as well as non-contaminated control and landfarm soil from near an oil refinery in Camamu Bay in Bahia, Brazil. The evolution of CO(2) production in all crude oil-contaminated microcosms showed potential for mineralization. Cluster analysis of denaturing gradient gel electrophoresis-derived samples generated with primers for gene amoA, which encodes the functional enzyme ammonia monooxygenase, showed differences in the sample contaminated with 5% compared to the other samples. Principal component analysis showed divergence of the non-contaminated samples from the 5% crude oil-contaminated sediment. A Venn diagram generated from the banding pattern of PCR-denaturing gradient gel electrophoresis was used to look for operational taxonomic units (OTUs) in common. Eight OTUs were found in non-contaminated sediments and in samples contaminated with 0.5, 1, or 2% crude oil. A Jaccard similarity index of 50% was found for samples contaminated with 0.1, 0.5, 1, and 2% crude oil. This is the first study that focuses on the impact of crude oil on the ammonia-oxidizing bacterium community in mangrove sediments from Camamu Bay.

Determination of Ammonia Oxidizing Bacteria and Nitrate Oxidizing Bacteria in Wastewater and Bioreactors

Science.gov (United States)

Francis, Somilez Asya

2014-01-01

The process of water purification has many different physical, chemical, and biological processes. One part of the biological process is the task of ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB). Both play critical roles in the treatment of wastewater by oxidizing toxic compounds. The broad term is nitrification, a naturally occurring process that is carried out by AOB and NOB by using oxidation to convert ammonia to nitrite and nitrite to nitrate. To monitor this biological activity, bacterial staining was performed on wastewater contained in inoculum tanks and biofilm samples from bioreactors. Using microscopy and qPCR, the purpose of this experiment was to determine if the population of AOB and NOB in wastewater and membrane bioreactors changed depending on temperature and hibernation conditions to determine the optimal parameters for AOB/NOB culture to effectively clean wastewater.

2009 Archaea: Ecology, Metabolism & Molecular Biology GRC

Energy Technology Data Exchange (ETDEWEB)

Furlow, Julie Maupin- [Univ. of Florida, Gainesville, FL (United States)

2009-07-26

Archaea, one of three major evolutionary lineages of life, are a fascinating and diverse group of microbes with deep roots overlapping those of eukaryotes. The focus of the 'Archaea: Ecology Metabolism & Molecular Biology' GRC conference expands on a number of emerging topics highlighting new paradigms in archaeal metabolism, genome function and systems biology; information processing; evolution and the tree of life; the ecology and diversity of archaea and their viruses; and industrial applications. The strength of this conference lies in its ability to couple a field with a rich history in high quality research with new scientific findings in an atmosphere of stimulating exchange. This conference remains an excellent opportunity for younger scientists to interact with world experts in this field.

Water addition regulates the metabolic activity of ammonia oxidizers responding to environmental perturbations in dry subhumid ecosystems.

Science.gov (United States)

Hu, Hang-Wei; Macdonald, Catriona A; Trivedi, Pankaj; Holmes, Bronwyn; Bodrossy, Levente; He, Ji-Zheng; Singh, Brajesh K

2015-02-01

Terrestrial arid and semi-arid ecosystems (drylands) constitute about 41% of the Earth's land surface and are predicted to experience increasing fluctuations in water and nitrogen availability. Mounting evidence has confirmed the significant importance of ammonia-oxidizing archaea (AOA) and bacteria (AOB) in nitrification, plant nitrogen availability and atmospheric N2 O emissions, but their responses to environmental perturbations in drylands remain largely unknown. Here we evaluate how the factorial combinations of irrigation and fertilization in forests and land-use change from grassland to forest affects the dynamics of AOA and AOB following a 6-year dryland field study. Potential nitrification rates and AOA and AOB abundances were significantly higher in the irrigated plots, accompanied by considerable changes in community compositions, but their responses to fertilization alone were not significant. DNA-stable isotope probing results showed increased (13) CO2 incorporation into the amoA gene of AOA, but not of AOB, in plots receiving water addition, coupled with significantly higher net mineralization and nitrification rates. High-throughput microarray analysis revealed that active AOA assemblages belonging to Nitrosopumilus and Nitrosotalea were increasingly labelled by (13) CO2 following irrigation. However, no obvious effects of land-use changes on nitrification rates or metabolic activity of AOA and AOB could be observed under dry conditions. We provide evidence that water addition had more important roles than nitrogen fertilization in influencing the autotrophic nitrification in dryland ecosystems, and AOA are increasingly involved in ammonia oxidation when dry soils become wetted. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

Functional Encyclopedia of Bacteria and Archaea

Energy Technology Data Exchange (ETDEWEB)

Blow, M. J.; Deutschbauer, A. M.; Hoover, C. A.; Lamson, J.; Lamson, J.; Price, M. N.; Waters, J.; Wetmore, K. M.; Bristow, J.; Arkin, A. P.

2013-03-20

Bacteria and Archaea exhibit a huge diversity of metabolic capabilities with fundamental importance in the environment, and potential applications in biotechnology. However, the genetic bases of these capabilities remain unclear due largely to an absence of technologies that link DNA sequence to molecular function. To address this challenge, we are developing a pipeline for high throughput annotation of gene function using mutagenesis, growth assays and DNA sequencing. By applying this pipeline to annotate gene function in 50 diverse microbes we hope to discover thousands of new gene functions and produce a proof of principle `Functional Encyclopedia of Bacteria and Archaea?.

Weakened activity of starved ammonia-oxidizing bacteria by the presence of pre-activated Nitrobacter winogradskyi

NARCIS (Netherlands)

Laanbroek, H.J.; Bär-Gilissen, M.J.

2002-01-01

Ammonia-oxidizing bacteria are able to maintain a high oxidizing potential during starvation. nitrite has a short-lasting stimulatory effect on the oxidation of ammonia after starvation when supplied simultaneously with fresh ammonium. To examine whether nitrite-oxidizing bacteria as partners in

Weakened activity of starved ammonia-oxidizing bacteria by the presence of pre-activated Nitrobacter winogradskyi

NARCIS (Netherlands)

Laanbroek, H.J.; Bär-Gilissen, M.J.

2002-01-01

Ammonia-oxidizing bacteria are able to maintain a high oxidizing potential during starvation. Nitrite has a short-lasting stimulatory effect on the oxidation of ammonia after starvation when supplied simultaneously with fresh ammonium9). To examine whether nitrite-oxidizing bacteria as partners in

A Zinc Oxide Nanorod Ammonia Microsensor Integrated with a Readout Circuit on-a-Chip

Directory of Open Access Journals (Sweden)

Chyan-Chyi Wu

2011-11-01

Full Text Available A zinc oxide nanorod ammonia microsensor integrated with a readout circuit on-a-chip fabricated using the commercial 0.35 mm complementary metal oxide semiconductor (CMOS process was investigated. The structure of the ammonia sensor is composed of a sensitive film and polysilicon electrodes. The ammonia sensor requires a post-process to etch the sacrificial layer, and to coat the sensitive film on the polysilicon electrodes. The sensitive film that is prepared by a hydrothermal method is made of zinc oxide. The sensor resistance changes when the sensitive film adsorbs or desorbs ammonia gas. The readout circuit is used to convert the sensor resistance into the voltage output. Experiments show that the ammonia sensor has a sensitivity of about 1.5 mV/ppm at room temperature.

Nitrous oxide production by lithotrophic ammonia-oxidizing bacteria and implications for engineered nitrogen-removal systems.

Science.gov (United States)

Chandran, Kartik; Stein, Lisa Y; Klotz, Martin G; van Loosdrecht, Mark C M

2011-12-01

Chemolithoautotrophic AOB (ammonia-oxidizing bacteria) form a crucial component in microbial nitrogen cycling in both natural and engineered systems. Under specific conditions, including transitions from anoxic to oxic conditions and/or excessive ammonia loading, and the presence of high nitrite (NO₂⁻) concentrations, these bacteria are also documented to produce nitric oxide (NO) and nitrous oxide (N₂O) gases. Essentially, ammonia oxidation in the presence of non-limiting substrate concentrations (ammonia and O₂) is associated with N₂O production. An exceptional scenario that leads to such conditions is the periodical switch between anoxic and oxic conditions, which is rather common in engineered nitrogen-removal systems. In particular, the recovery from, rather than imposition of, anoxic conditions has been demonstrated to result in N₂O production. However, applied engineering perspectives, so far, have largely ignored the contribution of nitrification to N₂O emissions in greenhouse gas inventories from wastewater-treatment plants. Recent field-scale measurements have revealed that nitrification-related N₂O emissions are generally far higher than emissions assigned to heterotrophic denitrification. In the present paper, the metabolic pathways, which could potentially contribute to NO and N₂O production by AOB have been conceptually reconstructed under conditions especially relevant to engineered nitrogen-removal systems. Taken together, the reconstructed pathways, field- and laboratory-scale results suggest that engineering designs that achieve low effluent aqueous nitrogen concentrations also minimize gaseous nitrogen emissions.

Evolutionary insights from studies on viruses of hyperthermophilic archaea.

Science.gov (United States)

Prangishvili, David

2003-05-01

The morphological diversity of viruses which parasitize hyperthermophilic archaea thriving at temperatures > or = 80 degrees C appears to exceed that of viruses of prokaryotes living at lower temperatures. Based on assumptions of the existence of viruses in the prebiotic phase of evolution and hot origins of cellular life, we suggest that this remarkable diversity could have its source in ancestral diversity of viral morphotypes in hot environments. Attempts are made to trace evolutionary relationships of viruses of hyperthermophilic archaea with other viruses.

Mrp Antiporters Have Important Roles in Diverse Bacteria and Archaea.

Science.gov (United States)

Ito, Masahiro; Morino, Masato; Krulwich, Terry A

2017-01-01

Mrp (Multiple resistance and pH) antiporter was identified as a gene complementing an alkaline-sensitive mutant strain of alkaliphilic Bacillus halodurans C-125 in 1990. At that time, there was no example of a multi-subunit type Na + /H + antiporter comprising six or seven hydrophobic proteins, and it was newly designated as the monovalent cation: proton antiporter-3 (CPA3) family in the classification of transporters. The Mrp antiporter is broadly distributed among bacteria and archaea, not only in alkaliphiles. Generally, all Mrp subunits, mrpA-G , are required for enzymatic activity. Two exceptions are Mrp from the archaea Methanosarcina acetivorans and the eubacteria Natranaerobius thermophilus , which are reported to sustain Na + /H + antiport activity with the MrpA subunit alone. Two large subunits of the Mrp antiporter, MrpA and MrpD, are homologous to membrane-embedded subunits of the respiratory chain complex I, NuoL, NuoM, and NuoN, and the small subunit MrpC has homology with NuoK. The functions of the Mrp antiporter include sodium tolerance and pH homeostasis in an alkaline environment, nitrogen fixation in Schizolobium meliloti , bile salt tolerance in Bacillus subtilis and Vibrio cholerae , arsenic oxidation in Agrobacterium tumefaciens , pathogenesis in Pseudomonas aeruginosa and Staphylococcus aureus , and the conversion of energy involved in metabolism and hydrogen production in archaea. In addition, some Mrp antiporters transport K + and Ca 2+ instead of Na + , depending on the environmental conditions. Recently, the molecular structure of the respiratory chain complex I has been elucidated by others, and details of the mechanism by which it transports protons are being clarified. Based on this, several hypotheses concerning the substrate transport mechanism in the Mrp antiporter have been proposed. The MrpA and MrpD subunits, which are homologous to the proton transport subunit of complex I, are involved in the transport of protons and their

Anaerobic ammonia removal in presence of organic matter: A novel route

International Nuclear Information System (INIS)

Sabumon, P.C.

2007-01-01

This study describes the feasibility of anaerobic ammonia removal process in presence of organic matter. Different sources of biomass collected from diverse eco-systems containing ammonia and organic matter (OM) were screened for potential anaerobic ammonia removal. Sequential batch studies confirmed the possibility of anaerobic ammonia removal in presence of OM, but ammonia was oxidized anoxically to nitrate (at oxidation reduction potential; ORP -248 ± 25 mV) by an unknown mechanism unlike in the reported anammox process. The oxygen required for oxidation of ammonia might have been generated through catalase enzymatic activity of facultative anaerobes in mixed culture. The oxygen generation possibility by catalase enzyme route was demonstrated. Among the inorganic electron acceptors (NO 2 - , NO 3 - and SO 4 2- ) studied, NO 2 - was found to be most effective in total nitrogen removal. Denitrification by the developed culture was much effective and faster compared to ammonia oxidation. The results of this study show that anaerobic ammonia removal is feasible in presence of OM. The novel nitrogen removal route is hypothesized as enzymatic anoxic oxidation of NH 4 + to NO 3 - , followed by denitrification via autotrophic and/or heterotrophic routes. The results of batch study were confirmed in continuous reactor operation

Influence of environmental ammonia on the production of nitric oxide and expression of inducible nitric oxide synthase in the freshwater air-breathing catfish (Heteropneustes fossilis)

Energy Technology Data Exchange (ETDEWEB)

Choudhury, Mahua G. [Biochemical Adaptation Laboratory, Department of Zoology, North-Eastern Hill University, Shillong 793022 (India); Saha, Nirmalendu, E-mail: nsaha@nehu.ac.in [Biochemical Adaptation Laboratory, Department of Zoology, North-Eastern Hill University, Shillong 793022 (India)

2012-07-15

Highlights: Black-Right-Pointing-Pointer High environmental ammonia caused more production and accumulation of NO in air-breathing catfish (Heteropneustes fossilis). Black-Right-Pointing-Pointer Hyper-ammonia stress caused induction and zonal specific expression of iNOS enzyme protein, mRNA expression in different tissues. Black-Right-Pointing-Pointer Activation of NF{kappa}B that resulted under hyper-ammonia stress was believed to be the cause of induction of iNOS gene. - Abstract: Nitric oxide (NO) is a highly versatile and unique ubiquitous signaling molecule, and is known to play diverse physiological functions in mammals including those of adaptation to various stresses. The present study reports on the influence of exposure to high external ammonia (HEA) on the production of nitric oxide (NO) and the expression of inducible nitric oxide synthase (iNOS), that produces NO from L-arginine in the freshwater air-breathing catfish (Heteropneustes fossilis), which is reported to tolerate a very HEA. Some levels of NO were found to be present in all the tissues and also in plasma of control fish, which further enhanced significantly in fishes treated with high concentrations of environmental ammonia (25 and 50 mM ammonium chloride) for 7 days, accompanied by more efflux of NO from the perfused liver. This was accomplished by the induction of iNOS activity in different tissues of fish exposed to HEA, which otherwise was not detectable in control fish. Exposure to 25 mM ammonium chloride also led to a significant expression of iNOS protein in different tissues, followed by further increase at 50 mM ammonium chloride. Further, there was an increase in the expression of iNOS mRNA in ammonia-treated fish, thus suggesting that the expression of iNOS gene under hyper-ammonia stress was probably regulated at the transcriptional level. Immunocytochemical analysis indicated that the expression of iNOS in different tissues was zonal specific and not expressed uniformly

Influence of environmental ammonia on the production of nitric oxide and expression of inducible nitric oxide synthase in the freshwater air-breathing catfish (Heteropneustes fossilis)

International Nuclear Information System (INIS)

Choudhury, Mahua G.; Saha, Nirmalendu

2012-01-01

Highlights: ► High environmental ammonia caused more production and accumulation of NO in air-breathing catfish (Heteropneustes fossilis). ► Hyper-ammonia stress caused induction and zonal specific expression of iNOS enzyme protein, mRNA expression in different tissues. ► Activation of NFκB that resulted under hyper-ammonia stress was believed to be the cause of induction of iNOS gene. - Abstract: Nitric oxide (NO) is a highly versatile and unique ubiquitous signaling molecule, and is known to play diverse physiological functions in mammals including those of adaptation to various stresses. The present study reports on the influence of exposure to high external ammonia (HEA) on the production of nitric oxide (NO) and the expression of inducible nitric oxide synthase (iNOS), that produces NO from L-arginine in the freshwater air-breathing catfish (Heteropneustes fossilis), which is reported to tolerate a very HEA. Some levels of NO were found to be present in all the tissues and also in plasma of control fish, which further enhanced significantly in fishes treated with high concentrations of environmental ammonia (25 and 50 mM ammonium chloride) for 7 days, accompanied by more efflux of NO from the perfused liver. This was accomplished by the induction of iNOS activity in different tissues of fish exposed to HEA, which otherwise was not detectable in control fish. Exposure to 25 mM ammonium chloride also led to a significant expression of iNOS protein in different tissues, followed by further increase at 50 mM ammonium chloride. Further, there was an increase in the expression of iNOS mRNA in ammonia-treated fish, thus suggesting that the expression of iNOS gene under hyper-ammonia stress was probably regulated at the transcriptional level. Immunocytochemical analysis indicated that the expression of iNOS in different tissues was zonal specific and not expressed uniformly throughout the organ. Hyper-ammonia stress also led to activation and nuclear

Continuous culture enrichments of ammonia-oxidizing bacteria at low ammonium concentrations

NARCIS (Netherlands)

Bollmann, A.; Laanbroek, H.J.

2001-01-01

Until now enrichments of ammonia-oxidizing bacteria from natural ammonium-limited environments have been performed mainly in the presence of much higher ammonia concentrations than those present in the natural environment and many have resulted in the enrichment and isolation of environmentally less

Continuous culture enrichments of ammonia-oxidizing bacteria at low ammonium concentrations

NARCIS (Netherlands)

Bollmann, A.; Laanbroek, H.J.

2001-01-01

Until now enrichments of ammonia-oxidizing bacteria from natural ammonium-limited environments have been performed mainly in the presence of much higher ammonia concentrations than those present in the natural environment and many have resulted in the enrichment and isolation of environmentally

The impact of temperature on microbial diversity and AOA activity in the Tengchong Geothermal Field, China

Science.gov (United States)

Li, Haizhou; Yang, Qunhui; Li, Jian; Gao, Hang; Li, Ping; Zhou, Huaiyang

2015-11-01

Using a culture-independent method that combines CARD-FISH, qPCR and 16S rDNA, we investigated the abundance, community structure and diversity of microbes along a steep thermal gradient (50-90 °C) in the Tengchong Geothermal Field. We found that Bacteria and Archaea abundance changed markedly with temperature changes and that the number of cells was lowest at high temperatures (90.8 °C). Under low-temperature conditions (52.3-74.6 °C), the microbial communities were dominated by Bacteria, which accounted for 60-80% of the total number of cells. At 74.6 °C, Archaea were dominant, and at 90.8 °C, they accounted for more than 90% of the total number of cells. Additionally, the microbial communities at high temperatures (74.6-90.8 °C) were substantially simpler than those at the low-temperature sites. Only a few genera (e.g., bacterial Caldisericum, Thermotoga and Thermoanaerobacter, archaeal Vulcanisaeta and Hyperthermus) often dominated in high-temperature environments. Additionally, a positive correlation between Ammonia-Oxidizing Archaea (AOA) activity and temperature was detected. AOA activity increased from 17 to 52 pmol of NO2- per cell d-1 with a temperature change from 50 to 70 °C.

The impact of temperature on microbial diversity and AOA activity in the Tengchong Geothermal Field, China.

Science.gov (United States)

Li, Haizhou; Yang, Qunhui; Li, Jian; Gao, Hang; Li, Ping; Zhou, Huaiyang

2015-11-26

Using a culture-independent method that combines CARD-FISH, qPCR and 16S rDNA, we investigated the abundance, community structure and diversity of microbes along a steep thermal gradient (50-90 °C) in the Tengchong Geothermal Field. We found that Bacteria and Archaea abundance changed markedly with temperature changes and that the number of cells was lowest at high temperatures (90.8 °C). Under low-temperature conditions (52.3-74.6 °C), the microbial communities were dominated by Bacteria, which accounted for 60-80% of the total number of cells. At 74.6 °C, Archaea were dominant, and at 90.8 °C, they accounted for more than 90% of the total number of cells. Additionally, the microbial communities at high temperatures (74.6-90.8 °C) were substantially simpler than those at the low-temperature sites. Only a few genera (e.g., bacterial Caldisericum, Thermotoga and Thermoanaerobacter, archaeal Vulcanisaeta and Hyperthermus) often dominated in high-temperature environments. Additionally, a positive correlation between Ammonia-Oxidizing Archaea (AOA) activity and temperature was detected. AOA activity increased from 17 to 52 pmol of NO2(-) per cell d(-1) with a temperature change from 50 to 70 °C.

Viruses of the Archaea

DEFF Research Database (Denmark)

Basta, T.; Garrett, Roger Antony; Prangishvili,, David

2009-01-01

Double-stranded deoxyribonucleic acid (DNA) viruses that infect members of the third domain of life, the Archaea, are diverse and exceptional in both their morphotypes and their genomic properties. The majority of characterized species infect hyperthermophilic hosts and carry morphological featur...

Diverse microbial species survive high ammonia concentrations

Science.gov (United States)

Kelly, Laura C.; Cockell, Charles S.; Summers, Stephen

2012-04-01

Planetary protection regulations are in place to control the contamination of planets and moons with terrestrial micro-organisms in order to avoid jeopardizing future scientific investigations relating to the search for life. One environmental chemical factor of relevance in extraterrestrial environments, specifically in the moons of the outer solar system, is ammonia (NH3). Ammonia is known to be highly toxic to micro-organisms and may disrupt proton motive force, interfere with cellular redox reactions or cause an increase of cell pH. To test the survival potential of terrestrial micro-organisms exposed to such cold, ammonia-rich environments, and to judge whether current planetary protection regulations are sufficient, soil samples were exposed to concentrations of NH3 from 5 to 35% (v/v) at -80°C and room temperature for periods up to 11 months. Following exposure to 35% NH3, diverse spore-forming taxa survived, including representatives of the Firmicutes (Bacillus, Sporosarcina, Viridibacillus, Paenibacillus, Staphylococcus and Brevibacillus) and Actinobacteria (Streptomyces). Non-spore forming organisms also survived, including Proteobacteria (Pseudomonas) and Actinobacteria (Arthrobacter) that are known to have environmentally resistant resting states. Clostridium spp. were isolated from the exposed soil under anaerobic culture. High NH3 was shown to cause a reduction in viability of spores over time, but spore morphology was not visibly altered. In addition to its implications for planetary protection, these data show that a large number of bacteria, potentially including spore-forming pathogens, but also environmentally resistant non-spore-formers, can survive high ammonia concentrations.

Diversity of halophilic archaea in fermented foods and human intestines and their application.

Science.gov (United States)

Lee, Han-Seung

2013-12-01

Archaea are prokaryotic organisms distinct from bacteria in the structural and molecular biological sense, and these microorganisms are known to thrive mostly at extreme environments. In particular, most studies on halophilic archaea have been focused on environmental and ecological researches. However, new species of halophilic archaea are being isolated and identified from high salt-fermented foods consumed by humans, and it has been found that various types of halophilic archaea exist in food products by culture-independent molecular biological methods. In addition, even if the numbers are not quite high, DNAs of various halophilic archaea are being detected in human intestines and much interest is given to their possible roles. This review aims to summarize the types and characteristics of halophilic archaea reported to be present in foods and human intestines and to discuss their application as well.

Oxidative destruction of ammonia for restoration of uranium solution mining sites

International Nuclear Information System (INIS)

Humenick, M.J.; Garwacka, K.

1984-01-01

A laboratory experimental research project was conducted to evaluate the use of chlorine for the oxidative destruction of residual ammonia that may remain in ground water after in-situ uranium solution mining operations. The work tested the idea of injecting high strength calcium hypochlorite solution into the mining zone to convert ammonia to nitrogen gas as a final cleanup process for ammonia removal from the ground water system. This paper details ammonia removal efficiency as a function of chlorine dose, reactant, and product material balances, and how the concept may be used as a final ground water restoration process

Oxidative destruction of ammonia for restoration of uranium solution mining sites

Energy Technology Data Exchange (ETDEWEB)

Humenick, M.J.; Garwacka, K.

1984-02-01

A laboratory experimental research project was conducted to evaluate the use of chlorine for the oxidative destruction of residual ammonia that may remain in ground water after in-situ uranium solution mining operations. The work tested the idea of injecting high strength calcium hypochlorite solution into the mining zone to convert ammonia to nitrogen gas as a final cleanup process for ammonia removal from the ground water system. This paper details ammonia removal efficiency as a function of chlorine dose, reactant, and product material balances, and how the concept may be used as a final ground water restoration process.

Oxidative destruction of ammonia for restoration of uranium solution mining sites

Energy Technology Data Exchange (ETDEWEB)

Humenick, M.J.; Garwacka, K.

1984-01-01

A laboratory experimental research project was conducted to evaluate the use of chlorine for the oxidative destruction of residual ammonia that may remain in ground water after in-situ uranium solution mining operations. The work tested the idea of injecting high strength calcium hypochlorite solution into the mining zone to convert ammonia to nitrogen gas as a final cleanup process for ammonia removal from the ground water system. This paper details ammonia removal efficiency as a function of chlorine dose, reactant, and product material balances, and how the concept may be used as a final ground water restoration process.

Direct electrochemical oxidation of ammonia on graphite as a treatment option for stored source-separated urine.

Science.gov (United States)

Zöllig, Hanspeter; Fritzsche, Cristina; Morgenroth, Eberhard; Udert, Kai M

2015-02-01

Electrolysis can be a viable technology for ammonia removal from source-separated urine. Compared to biological nitrogen removal, electrolysis is more robust and is highly amenable to automation, which makes it especially attractive for on-site reactors. In electrolytic wastewater treatment, ammonia is usually removed by indirect oxidation through active chlorine which is produced in-situ at elevated anode potentials. However, the evolution of chlorine can lead to the formation of chlorate, perchlorate, chlorinated organic by-products and chloramines that are toxic. This study focuses on using direct ammonia oxidation on graphite at low anode potentials in order to overcome the formation of toxic by-products. With the aid of cyclic voltammetry, we demonstrated that graphite is active for direct ammonia oxidation without concomitant chlorine formation if the anode potential is between 1.1 and 1.6 V vs. SHE (standard hydrogen electrode). A comparison of potentiostatic bulk electrolysis experiments in synthetic stored urine with and without chloride confirmed that ammonia was removed exclusively by continuous direct oxidation. Direct oxidation required high pH values (pH > 9) because free ammonia was the actual reactant. In real stored urine (pH = 9.0), an ammonia removal rate of 2.9 ± 0.3 gN·m(-2)·d(-1) was achieved and the specific energy demand was 42 Wh·gN(-1) at an anode potential of 1.31 V vs. SHE. The measurements of chlorate and perchlorate as well as selected chlorinated organic by-products confirmed that no chlorinated by-products were formed in real urine. Electrode corrosion through graphite exfoliation was prevented and the surface was not poisoned by intermediate oxidation products. We conclude that direct ammonia oxidation on graphite electrodes is a treatment option for source-separated urine with three major advantages: The formation of chlorinated by-products is prevented, less energy is consumed than in indirect ammonia oxidation and

Ammonia effect on hydrogenotrophic methanogens and syntrophic acetate oxidizing bacteria

DEFF Research Database (Denmark)

Wang, Han; Fotidis, Ioannis; Angelidaki, Irini

Substrates that contain high ammonia levels can cause inhibition on anaerobic digestion process and unstable biogas production. The aim of the current study was to assess the effects of different ammonia levels on pure strains of (syntrophic acetate oxidizing) SAO bacteria and hydrogenotrophic...... methanogens. Two pure strains of hydrogenotrophic methanogens (i.e: Methanoculleus bourgensis and Methanoculleus thermophiles) and two pure strains of SAO bacteria (i.e: Tepidanaerobacter acetatoxydans and Thermacetogenium phaeum) were inoculated under four different ammonia (0.26, 3, 5 and 7g NH4+-N......, the total incubation periods of hydrogenotrophic methanogens were significantly shorter compared to the SAO bacteria incubation periods. Thus, it seems that hydrogenotrophic methanogens could be equally, if not more, tolerant to high ammonia levels compared to SAO bacteria....

Bioprospecting Archaea: Focus on Extreme Halophiles

KAUST Repository

Antunes, André ; Simõ es, Marta F.; Grö tzinger, Stefan W.; Eppinger, Jö rg; Braganç a, Judith; Bajic, Vladimir B.

2016-01-01

knowledge, and (c) utilization of Archaea in biotechnology. They are increasingly employed in fields as diverse as biocatalysis, biocomputing, bioplastic production, bioremediation, bioengineering, food, pharmaceuticals, and nutraceuticals. This chapter

Retention of titanium dioxide nanoparticles in biological activated carbon filters for drinking water and the impact on ammonia reduction.

Science.gov (United States)

Liu, Zhiyuan; Yu, Shuili; Park, Heedeung; Liu, Guicai; Yuan, Qingbin

2016-06-01

Given the increasing discoveries related to the eco-toxicity of titanium dioxide (TiO2) nanoparticles (NPs) in different ecosystems and with respect to public health, it is important to understand their potential effects in drinking water treatment (DWT). The effects of TiO2 NPs on ammonia reduction, ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria (AOB) in biological activated carbon (BAC) filters for drinking water were investigated in static and dynamic states. In the static state, both the nitrification potential and AOB were significantly inhibited by 100 μg L(-1) TiO2 NPs after 12 h (p  0.05). In the dynamic state, different amounts of TiO2 NP pulses were injected into three pilot-scale BAC filters. The decay of TiO2 NPs in the BAC filters was very slow. Both titanium quantification and scanning electron microscope analysis confirmed the retention of TiO2 NPs in the BAC filters after 134 days of operation. Furthermore, the TiO2 NP pulses considerably reduced the performance of ammonia reduction. This study identified the retention of TiO2 NPs in BAC filters and the negative effect on the ammonia reduction, suggesting a potential threat to DWT by TiO2 NPs.

Protein Ser/Thr/Tyr phosphorylation in the Archaea.

Science.gov (United States)

Kennelly, Peter J

2014-04-04

The third domain of life, the Archaea (formerly Archaebacteria), is populated by a physiologically diverse set of microorganisms, many of which reside at the ecological extremes of our global environment. Although ostensibly prokaryotic in morphology, the Archaea share much closer evolutionary ties with the Eukarya than with the superficially more similar Bacteria. Initial genomic, proteomic, and biochemical analyses have revealed the presence of "eukaryotic" protein kinases and phosphatases and an intriguing set of serine-, threonine-, and tyrosine-phosphorylated proteins in the Archaea that may offer new insights into this important regulatory mechanism.

The response of ammonia-oxidizing microorganisms to trace metals and urine in two grassland soils in New Zealand.

Science.gov (United States)

Wang, Pengcheng; Di, Hong J; Cameron, Keith C; Tan, Qiling; Podolyan, Andriy; Zhao, Xiaohu; McLaren, Ron G; Hu, Chengxiao

2017-01-01

An incubation experiment was conducted to investigate the response of ammonia-oxidizing bacteria (AOB), ammonia-oxidizing archaea (AOA), and the nitrification rate to the contamination of Cu, Zn, and Cd in two New Zealand grassland soils. The soils spiked with different concentrations of Cu (20 and 50 mg kg -1 ), Zn (20 and 50 mg kg -1 ), and Cd (2 and 10 mg kg -1 ) were incubated for 14 days and then treated with 500 mg kg -1 urine-N before continuing incubation for a total of 115 days. Soils were sampled at intervals throughout the incubation. The nitrification rate in soils at each sampling period was determined, and the abundance of AOB and AOA was measured by real-time quantification polymerase chain reaction (qPCR) assay of the amoA gene copy numbers. The results revealed that moderate trace metal stress did not significantly affect the abundance of AOB and AOA in the two soils, probably due to the high organic matter content of the soils which would have reduced the toxic effect of the metals. Nitrification rates were much greater and the observable nitrification period was much shorter in the dairy farm (DF) soil, in which the AOB and AOA abundances were greater than those of the mixed cropping farm (MF) soil. AOB were shown to grow under high nitrogen conditions, whereas AOA were shown to grow under low N environments, with different metal concentrations. Therefore, nitrogen status rather than metal applications was the main determining factor for AOB and AOA growth in the two soils studied.

The effect of antimony-tin and indium-tin oxide supports on the catalytic activity of Pt nanoparticles for ammonia electro-oxidation

Energy Technology Data Exchange (ETDEWEB)

Silva, Júlio César M. [Department of Chemical & Biological Engineering, Centre for Catalysis Research and Innovation (CCRI), University of Ottawa, 161 Louis-Pasteur, Ottawa, ON K1N 6N5 (Canada); Instituto de Pesquisas Energéticas e Nucleares, IPEN/CNEN-SP, Av. Prof. Lineu Prestes, 2242 Cidade Universitária, CEP 05508-900, São Paulo, SP (Brazil); Piasentin, Ricardo M.; Spinacé, Estevam V.; Neto, Almir O. [Instituto de Pesquisas Energéticas e Nucleares, IPEN/CNEN-SP, Av. Prof. Lineu Prestes, 2242 Cidade Universitária, CEP 05508-900, São Paulo, SP (Brazil); Baranova, Elena A., E-mail: elena.baranova@uottawa.ca [Department of Chemical & Biological Engineering, Centre for Catalysis Research and Innovation (CCRI), University of Ottawa, 161 Louis-Pasteur, Ottawa, ON K1N 6N5 (Canada)

2016-09-01

Platinum nanoparticles supported on carbon (Pt/C) and carbon with addition of ITO (Pt/C-ITO (In{sub 2}O{sub 3}){sub 9}·(SnO{sub 2}){sub 1}) and ATO (Pt/C-ATO (SnO{sub 2}){sub 9}·(Sb{sub 2}O{sub 5}){sub 1}) oxides were prepared by sodium borohydride reduction method and used for ammonia electro-oxidation reaction (AmER) in alkaline media. The effect of the supports on the catalytic activity of Pt for AmER was investigated using electrochemical (cyclic voltammetry and chronoamperometry) and direct ammonia fuel cell (DAFC) experiments. X-ray diffraction (XRD) showed Pt peaks attributed to the face-centered cubic (fcc) structure, as well as peaks characteristic of In{sub 2}O{sub 3} in ITO support and cassiterite SnO{sub 2} phase of ATO support. According to transmission electron micrographs the mean particles sizes of Pt over carbon were 5.4, 4.9 and 4.7 nm for Pt/C, Pt/C-ATO and Pt/C-ITO, respectively. Pt/C-ITO catalysts showed the highest catalytic activity for ammonia electrooxidation in both electrochemical and fuel cell experiments. We attributed this to the presence of In{sub 2}O{sub 3} phase in ITO, which provides oxygenated or hydroxide species at lower potentials resulting in the removal of poisonous intermediate, i.e., atomic nitrogen (N{sub ads}) and promotion of ammonia electro-oxidation. - Highlights: • Oxide support effect on the catalytic activity of Pt towards ammonia electro-oxidation. • Direct ammonia fuel cell (DAFC) performance using Pt over different supports as anode. • Pt/C-ITO shows better catalytic activity for ammonia oxidation than Pt/C and Pt/C-ATO.

Diverse antimicrobial interactions of halophilic archaea and bacteria extend over geographical distances and cross the domain barrier.

Science.gov (United States)

Atanasova, Nina S; Pietilä, Maija K; Oksanen, Hanna M

2013-10-01

The significance of antimicrobial substances, halocins, produced by halophilic archaea and bacteria thriving in hypersaline environments is relatively unknown. It is suggested that their production might increase species diversity and give transient competitive advances to the producer strain. Halocin production is considered to be common among halophilic archaea, but there is a lack of information about halocins produced by bacteria in highly saline environments. We studied the antimicrobial activity of 68 halophilic archaea and 22 bacteria isolated from numerous geographically distant hypersaline environments. Altogether 144 antimicrobial interactions were found between the strains and aside haloarchaea, halophilic bacteria from various genera were identified as halocin producers. Close to 80% of the interactions were detected between microorganisms from different genera and in few cases, even across the domain boundary. Several of the strains produced halocins with a wide inhibitory spectrum as has been observed before. Most of the antimicrobial interactions were found between strains from distant sampling sites indicating that hypersaline environments around the world have similar microorganisms with the potential to produce wide activity range antimicrobials. © 2013 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

Intact polar lipids of ammonia-oxidizing Archaea: Structural diversity anapplication inmolecular ecology

NARCIS (Netherlands)

Pitcher, A.

2011-01-01

Non-extremophilic Crenarchaeota are ubiquitous, and comprise a major component of the microbial assemblages in many modern-day systems. Several studies have analyzed glycerol dialkyl glycerol tetraether (GDGT) membrane lipids synthesized by Crenarchaeota to interpret the presence, distribution, and

Archaea and Bacteria Acclimate to High Total Ammonia in a Methanogenic Reactor Treating Swine Waste

Directory of Open Access Journals (Sweden)

Sofia Esquivel-Elizondo

2016-01-01

Full Text Available Inhibition by ammonium at concentrations above 1000 mgN/L is known to harm the methanogenesis phase of anaerobic digestion. We anaerobically digested swine waste and achieved steady state COD-removal efficiency of around 52% with no fatty-acid or H2 accumulation. As the anaerobic microbial community adapted to the gradual increase of total ammonia-N (NH3-N from 890±295 to 2040±30 mg/L, the Bacterial and Archaeal communities became less diverse. Phylotypes most closely related to hydrogenotrophic Methanoculleus (36.4% and Methanobrevibacter (11.6%, along with acetoclastic Methanosaeta (29.3%, became the most abundant Archaeal sequences during acclimation. This was accompanied by a sharp increase in the relative abundances of phylotypes most closely related to acetogens and fatty-acid producers (Clostridium, Coprococcus, and Sphaerochaeta and syntrophic fatty-acid Bacteria (Syntrophomonas, Clostridium, Clostridiaceae species, and Cloacamonaceae species that have metabolic capabilities for butyrate and propionate fermentation, as well as for reverse acetogenesis. Our results provide evidence countering a prevailing theory that acetoclastic methanogens are selectively inhibited when the total ammonia-N concentration is greater than ~1000 mgN/L. Instead, acetoclastic and hydrogenotrophic methanogens coexisted in the presence of total ammonia-N of ~2000 mgN/L by establishing syntrophic relationships with fatty-acid fermenters, as well as homoacetogens able to carry out forward and reverse acetogenesis.

Investigation of Pristine Graphite Oxide as Room-Temperature Chemiresistive Ammonia Gas Sensing Material

Directory of Open Access Journals (Sweden)

Alexander G. Bannov

2017-02-01

Full Text Available Graphite oxide has been investigated as a possible room-temperature chemiresistive sensor of ammonia in a gas phase. Graphite oxide was synthesized from high purity graphite using the modified Hummers method. The graphite oxide sample was investigated using scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction, thermogravimetry and differential scanning calorimetry. Sensing properties were tested in a wide range of ammonia concentrations in air (10–1000 ppm and under different relative humidity levels (3%–65%. It was concluded that the graphite oxide–based sensor possessed a good response to NH3 in dry synthetic air (ΔR/R0 ranged from 2.5% to 7.4% for concentrations of 100–500 ppm and 3% relative humidity with negligible cross-sensitivity towards H2 and CH4. It was determined that the sensor recovery rate was improved with ammonia concentration growth. Increasing the ambient relative humidity led to an increase of the sensor response. The highest response of 22.2% for 100 ppm of ammonia was achieved at a 65% relative humidity level.

Co-Mn-Al Mixed Oxides as Catalysts for Ammonia Oxidation to N2O.

Czech Academy of Sciences Publication Activity Database

Ludvíková, Jana; Jablońska, M.; Jirátová, Květa; Chmielarz, L.; Balabánová, Jana; Kovanda, F.; Obalová, L.

2016-01-01

Roč. 42, č. 3 (2016), s. 2669-2690 ISSN 0922-6168 R&D Projects: GA ČR GA14-13750S Institutional support: RVO:67985858 Keywords : Co-Mn-Al mixed oxide s * catalytic ammonia oxidation * N2O production * mechanochemical production Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.369, year: 2016

Nitrosospira sp. Govern Nitrous Oxide Emissions in a Tropical Soil Amended With Residues of Bioenergy Crop

Directory of Open Access Journals (Sweden)

Késia S. Lourenço

2018-04-01

Full Text Available Organic vinasse, a residue produced during bioethanol production, increases nitrous oxide (N2O emissions when applied with inorganic nitrogen (N fertilizer in soil. The present study investigated the role of the ammonia-oxidizing bacteria (AOB community on the N2O emissions in soils amended with organic vinasse (CV: concentrated and V: non-concentrated plus inorganic N fertilizer. Soil samples and N2O emissions were evaluated at 11, 19, and 45 days after fertilizer application, and the bacterial and archaea gene (amoA encoding the ammonia monooxygenase enzyme, bacterial denitrifier (nirK, nirS, and nosZ genes and total bacteria were quantified by real time PCR. We also employed a deep amoA amplicon sequencing approach to evaluate the effect of treatment on the community structure and diversity of the soil AOB community. Both vinasse types applied with inorganic N application increased the total N2O emissions and the abundance of AOB. Nitrosospira sp. was the dominant AOB in the soil and was correlated with N2O emissions. However, the diversity and the community structure of AOB did not change with vinasse and inorganic N fertilizer amendment. The results highlight the importance of residues and fertilizer management in sustainable agriculture and can be used as a reference and an input tool to determine good management practices for organic fertilization.

Ammonia oxidizing bacteria community dynamics in a pilot-scale wastewater treatment plant.

Directory of Open Access Journals (Sweden)

Xiaohui Wang

Full Text Available BACKGROUND: Chemoautotrophic ammonia oxidizing bacteria (AOB have the metabolic ability to oxidize ammonia to nitrite aerobically. This metabolic feature has been widely used, in combination with denitrification, to remove nitrogen from wastewater in wastewater treatment plants (WWTPs. However, the relative influence of specific deterministic environmental factors to AOB community dynamics in WWTP is uncertain. The ecological principles underlying AOB community dynamics and nitrification stability and how they are related are also poorly understood. METHODOLOGY/PRINCIPAL FINDINGS: The community dynamics of ammonia oxidizing bacteria (AOB in a pilot-scale WWTP were monitored over a one-year period by Terminal Restriction Fragment Length Polymorphism (T-RFLP. During the study period, the effluent ammonia concentrations were almost below 2 mg/L, except for the first 60 days, indicting stable nitrification. T-RFLP results showed that, during the test period with stable nitrification, the AOB community structures were not stable, and the average change rate (every 15 days of AOB community structures was 10% ± 8%. The correlations between T-RFLP profiles and 10 operational and environmental parameters were tested by Canonical Correlation Analysis (CCA and Mantel test. The results indicated that the dynamics of AOB community correlated most strongly with Dissolved Oxygen (DO, effluent ammonia, effluent Biochemical Oxygen Demand (BOD and temperature. CONCLUSIONS/SIGNIFICANCE: This study suggests that nitrification stability is not necessarily accompanied by a stable AOB community, and provides insight into parameters controlling the AOB community dynamics within bioreactors with stable nitrification.

Low-temperature conversion of ammonia to nitrogen in water with ozone over composite metal oxide catalyst.

Science.gov (United States)

Chen, Yunnen; Wu, Ye; Liu, Chen; Guo, Lin; Nie, Jinxia; Chen, Yu; Qiu, Tingsheng

2018-04-01

As one of the most important water pollutants, ammonia nitrogen emissions have increased year by year, which has attracted people's attention. Catalytic ozonation technology, which involves production of ·OH radical with strong oxidation ability, is widely used in the treatment of organic-containing wastewater. In this work, MgO-Co 3 O 4 composite metal oxide catalysts prepared with different fabrication conditions have been systematically evaluated and compared in the catalytic ozonation of ammonia (50mg/L) in water. In terms of high catalytic activity in ammonia decomposition and high selectivity for gaseous nitrogen, the catalyst with MgO-Co 3 O 4 molar ratio 8:2, calcined at 500°C for 3hr, was the best one among the catalysts we tested, with an ammonia nitrogen removal rate of 85.2% and gaseous nitrogen selectivity of 44.8%. In addition, the reaction mechanism of ozonation oxidative decomposition of ammonia nitrogen in water with the metal oxide catalysts was discussed. Moreover, the effect of coexisting anions on the degradation of ammonia was studied, finding that SO 4 2- and HCO 3 - could inhibit the catalytic activity while CO 3 2- and Br - could promote it. The presence of coexisting cations had very little effect on the catalytic ozonation of ammonia nitrogen. After five successive reuses, the catalyst remained stable in the catalytic ozonation of ammonia. Copyright © 2017. Published by Elsevier B.V.

Decreasing ammonia inhibition in thermophilic methanogenic bioreactors using carbon fiber textiles.

Science.gov (United States)

Sasaki, Kengo; Morita, Masahiko; Hirano, Shin-ichi; Ohmura, Naoya; Igarashi, Yasuo

2011-05-01

Ammonia accumulation is one of the main causes of the loss of methane production observed during fermentation. We investigated the effect of addition of carbon fiber textiles (CFT) to thermophilic methanogenic bioreactors with respect to ammonia tolerance during the process of degradation of artificial garbage slurry, by comparing the performance of the reactors containing CFT with the performance of reactors without CFT. Under total ammonia-N concentrations of 3,000 mg L(-1), the reactors containing CFT were found to mediate stable removal of organic compounds and methane production. Under these conditions, high levels of methanogenic archaea were retained at the CFT, as determined by 16S rRNA gene analysis for methanogenic archaea. In addition, Methanobacterium sp. was found to be dominant in the suspended fraction, and Methanosarcina sp. was dominant in the retained fraction of the reactors with CFT. However, the reactors without CFT had lower rates of removal of organic compounds and production of methane under total ammonia-N concentrations of 1,500 mg L(-1). Under this ammonia concentration, a significant accumulation of acetate was observed in the reactors without CFT (130.0 mM), relative to the reactors with CFT (4.2 mM). Only Methanobacterium sp. was identified in the reactors without CFT. These results suggest that CFT enables stable proliferation of aceticlastic methanogens by preventing ammonia inhibition. This improves the process of stable garbage degradation and production of methane in thermophilic bioreactors that include high levels of ammonia.

Distribution and abundance of archaeal and bacterial ammonia oxidizers in the sediments of the Dongjiang River, a drinking water supply for Hong Kong.

Science.gov (United States)

Sun, Wei; Xia, Chunyu; Xu, Meiying; Guo, Jun; Wang, Aijie; Sun, Guoping

2013-01-01

Ammonia-oxidizing archaea (AOA) and bacteria (AOB) play important roles in nitrification. However, limited information about the characteristics of AOA and AOB in the river ecosystem is available. The distribution and abundance of AOA and AOB in the sediments of the Dongjiang River, a drinking water source for Hong Kong, were investigated by clone library analysis and quantitative real-time PCR. Phylogenetic analysis showed that Group 1.1b- and Group 1.1b-associated sequences of AOA predominated in sediments with comparatively high carbon and nitrogen contents (e.g. total carbon (TC) >13 g kg(-1) sediment, NH4(+)-N >144 mg kg(-1) sediment), while Group 1.1a- and Group 1.1a-associated sequences were dominant in sediments with opposite conditions (e.g. TC <4 g kg(-1) sediment, NH4(+)-N <93 mg kg(-1) sediment). Although Nitrosomonas- and Nitrosospira-related sequences of AOB were detected in the sediments, nearly 70% of the sequences fell into the Nitrosomonas-like B cluster, suggesting similar sediment AOB communities along the river. Higher abundance of AOB than AOA was observed in almost all of the sediments in the Dongjiang River, while significant correlations were only detected between the distribution of AOA and the sediment pH and TC, which suggested that AOA responded more sensitively than AOB to variations of environmental factors. These results extend our knowledge about the environmental responses of ammonia oxidizers in the river ecosystem.

Archaea Signal Recognition Particle Shows the Way

Directory of Open Access Journals (Sweden)

Christian Zwieb

2010-01-01

Full Text Available Archaea SRP is composed of an SRP RNA molecule and two bound proteins named SRP19 and SRP54. Regulated by the binding and hydrolysis of guanosine triphosphates, the RNA-bound SRP54 protein transiently associates not only with the hydrophobic signal sequence as it emerges from the ribosomal exit tunnel, but also interacts with the membrane-associated SRP receptor (FtsY. Comparative analyses of the archaea genomes and their SRP component sequences, combined with structural and biochemical data, support a prominent role of the SRP RNA in the assembly and function of the archaea SRP. The 5e motif, which in eukaryotes binds a 72 kilodalton protein, is preserved in most archaea SRP RNAs despite the lack of an archaea SRP72 homolog. The primary function of the 5e region may be to serve as a hinge, strategically positioned between the small and large SRP domain, allowing the elongated SRP to bind simultaneously to distant ribosomal sites. SRP19, required in eukaryotes for initiating SRP assembly, appears to play a subordinate role in the archaea SRP or may be defunct. The N-terminal A region and a novel C-terminal R region of the archaea SRP receptor (FtsY are strikingly diverse or absent even among the members of a taxonomic subgroup.

Coupling Solid Oxide Electrolyser (SOE) and ammonia production plant

International Nuclear Information System (INIS)

Cinti, Giovanni; Frattini, Domenico; Jannelli, Elio; Desideri, Umberto; Bidini, Gianni

2017-01-01

Highlights: • An innovative NH 3 production plant was designed. • CO 2 emissions and energy consumption are studied in three different designs. • High temperature electrolysis allows to achieve high efficiency and heat recovery. • The coupling permits storage of electricity into a liquid carbon free chemical. - Abstract: Ammonia is one of the most produced chemicals worldwide and is currently synthesized using nitrogen separated from air and hydrogen from natural gas reforming with consequent high consumption of fossil fuel and high emission of CO 2 . A renewable path for ammonia production is desirable considering the potential development of ammonia as energy carrier. This study reports design and analysis of an innovative system for the production of green ammonia using electricity from renewable energy sources. This concept couples Solid Oxide Electrolysis (SOE), for the production of hydrogen, with an improved Haber Bosch Reactor (HBR), for ammonia synthesis. An air separator is also introduced to supply pure nitrogen. SOE operates with extremely high efficiency recovering high temperature heat from the Haber-Bosch reactor. Aspen was used to develop a model to study the performance of the plant. Both the SOE and the HBR operate at 650 °C. Ammonia production with zero emission of CO 2 can be obtained with a reduction of 40% of power input compared to equivalent plants.

Simultaneous Fe(III) reduction and ammonia oxidation process in Anammox sludge.

Science.gov (United States)

Li, Xiang; Huang, Yong; Liu, Heng-Wei; Wu, Chuan; Bi, Wei; Yuan, Yi; Liu, Xin

2018-02-01

In recent years, there have been a number of reports on the phenomenon in which ferric iron (Fe(III)) is reduced to ferrous iron [Fe(II)] in anaerobic environments, accompanied by simultaneous oxidation of ammonia to NO 2 - , NO 3 - , or N 2. However, studies on the relevant reaction characteristics and mechanisms are rare. Recently, in research on the effect of Fe(III) on the activity of Anammox sludge, excess ammonia oxidization has also been found. Hence, in the present study, Fe(III) was used to serve as the electron acceptor instead of NO 2 - , and the feasibility and characteristics of Anammox coupled to Fe(III) reduction (termed Feammox) were investigated. After 160days of cultivation, the conversion rate of ammonia in the reactor was above 80%, accompanied by the production of a large amount of NO 3 - and a small amount of NO 2 - . The total nitrogen removal rate was up to 71.8%. Furthermore, quantities of Fe(II) were detected in the sludge fluorescence in situ hybridization (FISH) and denaturated gradient gel electrophoresis (DGGE) analyses further revealed that in the sludge, some Anammox bacteria were retained, and some microbes were enriched during the acclimatization process. We thus deduced that in Anammox sludge, Fe(III) reduction takes place together with ammonia oxidation to NO 2 - and NO 3 - along with the Anammox process. Copyright © 2017. Published by Elsevier B.V.

Ammonia-oxidizing bacteria: A model for molecular microbial ecology

NARCIS (Netherlands)

Kowalchuk, G.A.; Stephen, J.R.

2001-01-01

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

Application of a Chemiluminescence Detector for the Measurement of Total Oxides of Nitrogen and Ammonia in the Atmosphere

Science.gov (United States)

Hodgeson, J. A.; Bell, J. P.; Rehme, K. A.; Krost, K. J.; Stevens, R. K.

1971-01-01

By means of the thermal conversion of nitrogen dioxide to the nitric oxide, the chemiluminescent nitric oxide monitor, based on the nitric oxide plus ozone reaction, may be used for monitoring nitrogen dioxide plus nitric oxide (NO(x)). Under conditions previously described, ammonia is also converted to nitric oxide and therefore interferes. A metal surface, gold wool or stainless steel, operated at two different temperatures has been used to convert only nitrogen dioxide or nitrogen dioxide plus ammonia. Quantitative conversion of nitrogen dioxide to nitric oxide has been obtained at temperatures as low as 200 C. Conversion of ammonia is effected at temperatures of 300 C or higher. By the addition of a converter the basic nitric oxide monitor may be used for measuring NO(x) or NO(x) plus ammonia. As an alternate mode, for a fixed high temperature, a specific scrubber is described for removing NH3 without affecting NO2 concentrations.

Spectroscopic and electrical sensing mechanism in oxidant-mediated polypyrrole nanofibers/nanoparticles for ammonia gas

International Nuclear Information System (INIS)

Ishpal; Kaur, Amarjeet

2013-01-01

Ammonia gas sensing mechanism in oxidant-mediated polypyrrole (PPy) nanofibers/nanoparticles has been studied through spectroscopic and electrical investigations. PPy nanofibers/nanoparticles have been synthesized by chemical oxidation method in the presence of various oxidizing agents such as ammonium persulfate (APS), potassium persulfate (PPS), vanadium pentoxide (V 2 O 5 ), and iron chloride (FeCl 3 ). Scanning electron microscopy study revealed that PPy nanofibers of about 63, 71 and 79 nm diameters were formed in the presence of APS, PPS, V 2 O 5 , respectively, while PPy nanoparticles of about 100–110 nm size were obtained in the presence of FeCl 3 as an oxidant. The structural investigations and confirmation of synthesis of PPy were established through Fourier transform infrared and Raman spectroscopy. The gas sensing behavior of the prepared PPy samples is investigated by measuring the electrical resistance in ammonia environment. The observed gas sensing response (ΔR/Rx100) at 100 ppm level of ammonia is ∼4.5 and 18 % for the samples prepared with oxidizing agents FeCl 3 and APS, respectively, and by changing the ammonia level from 50 to 300 ppm, the sensing response varies from ∼4.5 to 11 % and ∼10 to 39 %, respectively. Out of all four samples, the PPy nanofibers prepared in the presence of APS have shown the best sensing response. The mechanism of gas sensing response of the PPy samples has been investigated through Raman spectroscopy study. The decrease of charge carrier concentration through reduction of polymeric chains has been recognized through Raman spectroscopic measurements recorded in ammonia environment.

Complete genome sequence of Nitrosomonas sp. Is79, an ammonia oxidizing bacterium adapted to low ammonium concentrations

NARCIS (Netherlands)

Bollmann, A.; Sedlacek, C.J.; Norton, J.; Laanbroek, H.J.; Suwa, Y.; Stein, L.Y.; Klotz, M.G.; Arp, D.; Sayavedra-Soto, L.; Lu, M.; Bruce, D.; Detter, C.; Tapia, R.; Han, J.; Woyke, T.; Lucas, S.; Pitluck, S.; Pennacchio, L.; Nolan, M.; Land, M.L.; Huntemann, M.; Deshpande, S.; Han, C.; Chen, A.; Kyrpides, N.; Mavromatis, K.; Markowitz, V.; Szeto, E.; Ivanova, N.; Mikhailova, N.; Pagani, I.; Pati, A.; Peters, L.; Ovchinnikova, G.; Goodwin, L.

2013-01-01

Nitrosomonas sp. Is79 is a chemolithoautotrophic ammonia-oxidizing bacterium that belongs to the family Nitrosomonadaceae within the phylum Proteobacteria. Ammonia oxidation is the first step of nitrification, an important process in the global nitrogen cycle ultimately resulting in the production

Diversity and ubiquity of thermophilic methanogenic archaea in temperate anoxic soils.

Science.gov (United States)

Wu, Xiao-Lei; Friedrich, Michael W; Conrad, Ralf

2006-03-01

Temperate rice field soil from Vercelli (Italy) contains moderately thermophilic methanogens of the yet uncultivated rice cluster I (RC-I), which become prevalent upon incubation at temperatures of 45-50 degrees C. We studied whether such thermophilic methanogens were ubiquitously present in anoxic soils. Incubation of different rice field soils (from Italy, China and the Philippines) and flooded riparian soils (from the Netherlands) at 45 degrees C resulted in vigorous CH(4) production after a lag phase of about 10 days. The archaeal community structure in the soils was analysed by terminal restriction fragment length polymorphism (T-RFLP) targeting the SSU rRNA genes retrieved from the soil, and by cloning and sequencing. Clones of RC-I methanogens mostly exhibited T-RF of 393 bp, but also terminal restriction fragment (T-RF) of 158 and 258 bp length, indicating a larger diversity than previously assumed. No RC-I methanogens were initially found in flooded riparian soils. However, these archaea became abundant upon incubation of the soil at 45 degrees C. Thermophilic RC-I methanogens were also found in the rice field soils from Pavia, Pila and Gapan. However, the archaeal communities in these soils also contained other methanogenic archaea at high temperature. Rice field soil from Buggalon, on the other hand, only contained thermophilic Methanomicrobiales rather than RC-I methanogens, and rice field soil from Jurong mostly Methanomicrobiales and only a few RC-I methanogens. The archaeal community of rice field soil from Zhenjiang almost exclusively consisted of Methanosarcinaceae when incubated at high temperature. Our results show that moderately thermophilic methanogens are common in temperate soils. However, RC-I methanogens are not always dominating or ubiquitous.

Complete genome sequence of Nitrosomonas sp. Is79, an ammonia oxidizing bacterium adapted to low ammonium concentrations

Energy Technology Data Exchange (ETDEWEB)

Bollmann, Annette [Miami University, Oxford, OH; Sedlacek, Christopher J [Miami University, Oxford, OH; Laanbroek, Hendrikus J [Netherlands Institute of Ecology (NIOO-KNAW); Suwa, Yuichi [Chuo University, Tokyo, Japan; Stein, Lisa Y [University of California, Riverside; Klotz, Martin G [University of Louisville, Louisville; Arp, D J [Oregon State University; Sayavedra-Soto, LA [Oregon State University; Lu, Megan [Los Alamos National Laboratory (LANL); Bruce, David [Los Alamos National Laboratory (LANL); Detter, J. Chris [U.S. Department of Energy, Joint Genome Institute; Tapia, Roxanne [Los Alamos National Laboratory (LANL); Han, James [U.S. Department of Energy, Joint Genome Institute; Woyke, Tanja [U.S. Department of Energy, Joint Genome Institute; Lucas, Susan [U.S. Department of Energy, Joint Genome Institute; Pitluck, Sam [U.S. Department of Energy, Joint Genome Institute; Pennacchio, Len [U.S. Department of Energy, Joint Genome Institute; Nolan, Matt [U.S. Department of Energy, Joint Genome Institute; Land, Miriam L [ORNL; Huntemann, Marcel [U.S. Department of Energy, Joint Genome Institute; Deshpande, Shweta [U.S. Department of Energy, Joint Genome Institute; Han, Cliff [Los Alamos National Laboratory (LANL); Chen, Amy [U.S. Department of Energy, Joint Genome Institute; Kyrpides, Nikos C [U.S. Department of Energy, Joint Genome Institute; Mavromatis, K [U.S. Department of Energy, Joint Genome Institute; Markowitz, Victor [U.S. Department of Energy, Joint Genome Institute; Szeto, Ernest [U.S. Department of Energy, Joint Genome Institute; Ivanova, N [U.S. Department of Energy, Joint Genome Institute; Mikhailova, Natalia [U.S. Department of Energy, Joint Genome Institute; Pagani, Ioanna [U.S. Department of Energy, Joint Genome Institute; Pati, Amrita [U.S. Department of Energy, Joint Genome Institute; Peters, Lin [U.S. Department of Energy, Joint Genome Institute; Ovchinnikova, Galina [U.S. Department of Energy, Joint Genome Institute; Goodwin, Lynne A. [Los Alamos National Laboratory (LANL)

2013-01-01

Nitrosomonas sp. Is79 is a chemolithoautotrophic ammonia-oxidizing bacterium that belongs to the family Nitrosomonadaceae within the phylum Proteobacteria. Ammonia oxidation is the first step of nitrification, an important process in the global nitrogen cycle ultimately resulting in the production of nitrate. Nitrosomonas sp. Is79 is an ammonia oxidizer of high interest because it is adapted to low ammonium and can be found in freshwater environments around the world. The 3,783,444-bp chromosome with a total of 3,553 protein coding genes and 44 RNA genes was sequenced by the DOE-Joint Genome Institute Program CSP 2006.

RESULTS OF INITIAL AMMONIA OXIDATION TESTING

Energy Technology Data Exchange (ETDEWEB)

Nash, C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Fowley, M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2016-12-30

This memo presents an experimental survey of aqueous phase chemical processes to remove aqueous ammonia from waste process streams. Ammonia is generated in both the current Hanford waste flowsheet and in future waste processing. Much ammonia will be generated in the Low Activity Waste (LAW) melters.i Testing with simulants in glass melters at Catholic University has demonstrated the significant ammonia production.ii The primary reaction there is the reducing action of sugar on nitrate in the melter cold cap. Ammonia has been found to be a problem in secondary waste stabilization. Ammonia vapors are noxious and destruction of ammonia could reduce hazards to waste treatment process personnel. It is easily evolved especially when ammonia-bearing solutions are adjusted to high pH.

Molecular Analysis of Ammonia-Oxidizing Bacteria of the β Subdivision of the Class Proteobacteria in Compost and Composted Materials

Science.gov (United States)

Kowalchuk, George A.; Naoumenko, Zinaida S.; Derikx, Piet J. L.; Felske, Andreas; Stephen, John R.; Arkhipchenko, Irina A.

1999-01-01

Although the practice of composting animal wastes for use as biofertilizers has increased in recent years, little is known about the microorganisms responsible for the nitrogen transformations which occur in compost and during the composting process. Ammonia is the principle available nitrogenous compound in composting material, and the conversion of this compound to nitrite in the environment by chemolithotrophic ammonia-oxidizing bacteria is an essential step in nitrogen cycling. Therefore, the distribution of ammonia-oxidizing members of the β subdivision of the class Proteobacteria in a variety of composting materials was assessed by amplifying 16S ribosomal DNA (rDNA) and 16S rRNA by PCR and reverse transcriptase PCR (RT-PCR), respectively. The PCR and RT-PCR products were separated by denaturing gradient gel electrophoresis (DGGE) and were identified by hybridization with a hierarchical set of oligonucleotide probes designed to detect ammonia oxidizer-like sequence clusters in the genera Nitrosospira and Nitrosomonas. Ammonia oxidizer-like 16S rDNA was detected in almost all of the materials tested, including industrial and experimental composts, manure, and commercial biofertilizers. A comparison of the DGGE and hybridization results after specific PCR and RT-PCR suggested that not all of the different ammonia oxidizer groups detected in compost are equally active. amoA, the gene encoding the active-site-containing subunit of ammonia monooxygenase, was also targeted by PCR, and template concentrations were estimated by competitive PCR. Detection of ammonia-oxidizing bacteria in the composts tested suggested that such materials may not be biologically inert with respect to nitrification and that the fate of nitrogen during composting and compost storage may be affected by the presence of these organisms. PMID:9925559

Effect of biowaste sludge maturation on the diversity of thermophilic bacteria and archaea in an anaerobic reactor.

Science.gov (United States)

Goberna, M; Insam, H; Franke-Whittle, I H

2009-04-01

Prokaryotic diversity was investigated near the inlet and outlet of a plug-flow reactor. After analyzing 800 clones, 50 bacterial and 3 archaeal phylogenetic groups were defined. Clostridia (>92%) dominated among bacteria and Methanoculleus (>90%) among archaea. Significant changes in pH and volatile fatty acids did not invoke a major shift in the phylogenetic groups. We suggest that the environmental filter imposed by the saline conditions (20 g liter(-1)) selected a stable community of halotolerant and halophilic prokaryotes.

Nitrate Reduction to Nitrite, Nitric Oxide and Ammonia by Gut Bacteria under Physiological Conditions

Science.gov (United States)

Tiso, Mauro; Schechter, Alan N.

2015-01-01

The biological nitrogen cycle involves step-wise reduction of nitrogen oxides to ammonium salts and oxidation of ammonia back to nitrites and nitrates by plants and bacteria. Neither process has been thought to have relevance to mammalian physiology; however in recent years the salivary bacterial reduction of nitrate to nitrite has been recognized as an important metabolic conversion in humans. Several enteric bacteria have also shown the ability of catalytic reduction of nitrate to ammonia via nitrite during dissimilatory respiration; however, the importance of this pathway in bacterial species colonizing the human intestine has been little studied. We measured nitrite, nitric oxide (NO) and ammonia formation in cultures of Escherichia coli, Lactobacillus and Bifidobacterium species grown at different sodium nitrate concentrations and oxygen levels. We found that the presence of 5 mM nitrate provided a growth benefit and induced both nitrite and ammonia generation in E.coli and L.plantarum bacteria grown at oxygen concentrations compatible with the content in the gastrointestinal tract. Nitrite and ammonia accumulated in the growth medium when at least 2.5 mM nitrate was present. Time-course curves suggest that nitrate is first converted to nitrite and subsequently to ammonia. Strains of L.rhamnosus, L.acidophilus and B.longum infantis grown with nitrate produced minor changes in nitrite or ammonia levels in the cultures. However, when supplied with exogenous nitrite, NO gas was readily produced independently of added nitrate. Bacterial production of lactic acid causes medium acidification that in turn generates NO by non-enzymatic nitrite reduction. In contrast, nitrite was converted to NO by E.coli cultures even at neutral pH. We suggest that the bacterial nitrate reduction to ammonia, as well as the related NO formation in the gut, could be an important aspect of the overall mammalian nitrate/nitrite/NO metabolism and is yet another way in which the microbiome

Nitrate reduction to nitrite, nitric oxide and ammonia by gut bacteria under physiological conditions.

Directory of Open Access Journals (Sweden)

Mauro Tiso

Full Text Available The biological nitrogen cycle involves step-wise reduction of nitrogen oxides to ammonium salts and oxidation of ammonia back to nitrites and nitrates by plants and bacteria. Neither process has been thought to have relevance to mammalian physiology; however in recent years the salivary bacterial reduction of nitrate to nitrite has been recognized as an important metabolic conversion in humans. Several enteric bacteria have also shown the ability of catalytic reduction of nitrate to ammonia via nitrite during dissimilatory respiration; however, the importance of this pathway in bacterial species colonizing the human intestine has been little studied. We measured nitrite, nitric oxide (NO and ammonia formation in cultures of Escherichia coli, Lactobacillus and Bifidobacterium species grown at different sodium nitrate concentrations and oxygen levels. We found that the presence of 5 mM nitrate provided a growth benefit and induced both nitrite and ammonia generation in E.coli and L.plantarum bacteria grown at oxygen concentrations compatible with the content in the gastrointestinal tract. Nitrite and ammonia accumulated in the growth medium when at least 2.5 mM nitrate was present. Time-course curves suggest that nitrate is first converted to nitrite and subsequently to ammonia. Strains of L.rhamnosus, L.acidophilus and B.longum infantis grown with nitrate produced minor changes in nitrite or ammonia levels in the cultures. However, when supplied with exogenous nitrite, NO gas was readily produced independently of added nitrate. Bacterial production of lactic acid causes medium acidification that in turn generates NO by non-enzymatic nitrite reduction. In contrast, nitrite was converted to NO by E.coli cultures even at neutral pH. We suggest that the bacterial nitrate reduction to ammonia, as well as the related NO formation in the gut, could be an important aspect of the overall mammalian nitrate/nitrite/NO metabolism and is yet another way in

Viruses of the Archaea: a unifying view

DEFF Research Database (Denmark)

Prangishvili, David; Forterre, Patrick; Garrett, Roger Antony

2006-01-01

DNA viruses of the Archaea have highly diverse and often exceptionally complex morphotypes. Many have been isolated from geothermally heated hot environments, raising intriguing questions about their origins, and contradicting the widespread notion of limited biodiversity in extreme environments...

First description of giant Archaea (Thaumarchaeota) associated with putative bacterial ectosymbionts in a sulfidic marine habitat.

Science.gov (United States)

Muller, Félix; Brissac, Terry; Le Bris, Nadine; Felbeck, Horst; Gros, Olivier

2010-08-01

Archaea may be involved in global energy cycles, and are known for their ability to interact with eukaryotic species (sponges, corals and ascidians) or as archaeal-bacterial consortia. The recently proposed phylum Thaumarchaeota may represent the deepest branching lineage in the archaeal phylogeny emerging before the divergence between Euryarchaeota and Crenarchaeota. Here we report the first characterization of two marine thaumarchaeal species from shallow waters that consist of multiple giant cells. One species is coated with sulfur-oxidizing γ-Proteobacteria. These new uncultured thaumarchaeal species are able to live in the sulfide-rich environments of a tropical mangrove swamp, either on living tissues such as roots or on various kinds of materials such as stones, sunken woods, etc. These archaea and archaea/bacteria associations have been studied using light microscopy, transmission electron microscopy and scanning electron microscopy. Species identification of archaeons and the putative bacterial symbiont have been assessed by 16S small subunit ribosomal RNA analysis. The sulfur-oxidizing ability of the bacteria has been assessed by genetic investigation on alpha-subunit of the adenosine-5'-phosphosulfate reductase/oxidase's (AprA). Species identifications have been confirmed by fluorescence in situ hybridization using specific probes designed in this study. In this article, we describe two new giant archaeal species that form the biggest archaeal filaments ever observed. One of these species is covered by a specific biofilm of sulfur-oxidizing γ-Proteobacteria. This study highlights an unexpected morphological and genetic diversity of the phylum Thaumarchaeota. © 2010 Society for Applied Microbiology and Blackwell Publishing Ltd.

Treatment of ammonia by catalytic wet oxidation process over platinum-rhodium bimetallic catalyst in a trickle-bed reactor: effect of pH.

Science.gov (United States)

Hung, Chang-Mao; Lin, Wei-Bang; Ho, Ching-Lin; Shen, Yun-Hwei; Hsia, Shao-Yi

2010-08-01

This work adopted aqueous solutions of ammonia for use in catalytic liquid-phase reduction in a trickle-bed reactor with a platinum-rhodium bimetallic catalyst, prepared by the co-precipitation of chloroplatinic acid (H2PtCl6) and rhodium nitrate [Rh(NO3)3]. The experimental results demonstrated that a minimal amount of ammonia was removed from the solution by wet oxidation in the absence of any catalyst, while approximately 97.0% of the ammonia was removed by wet oxidation over the platinum-rhodium bimetallic catalyst at 230 degrees C with an oxygen partial pressure of 2.0 MPa. The oxidation of ammonia has been studied as a function of pH, and the main reaction products were determined. A synergistic effect is manifest in the platinum-rhodium bimetallic structure, in which the material has the greatest capacity to reduce ammonia. The reaction pathway linked the oxidizing ammonia to nitric oxide, nitrogen, and water.

Complete nitrification by a single microorganism

DEFF Research Database (Denmark)

van Kessel, Maartje A. H. J.; Speth, Daan R.; Albertsen, Mads

2015-01-01

Nitrification is a two-step process where ammonia is first oxidized to nitrite by ammonia-oxidizing bacteria and/or archaea, and subsequently to nitrate by nitrite-oxidizing bacteria. Already described by Winogradsky in 18901, this division of labour between the two functional groups is a general...

Potato cultivar type affects the structure of ammonia oxidizer communities in field soil under potato beyond the rhizosphere

NARCIS (Netherlands)

Cavalcante Franco Dias, A.; Hoogwout, E.F.; de Cassia Pereira e Silva, M.; Falcão Salles, J.; van Overbeek, L.S.; van Elsas, J.D.

The effects of plants on the microbiota involved in the oxidation of ammonia in soils have been controversial. Here, we investigated the dynamics in the abundances and community structures of the bacterial and archaeal ammonia oxidizers (AOB and AOA, respectively) in two fields that were cropped

Vertical profiles of community abundance and diversity of anaerobic methanotrophic archaea (ANME) and bacteria in a simple waste landfill in north China.

Science.gov (United States)

Dong, Jun; Ding, Linjie; Wang, Xu; Chi, Zifang; Lei, Jiansen

2015-03-01

Anaerobic methane oxidation (AMO) is considered to be an important sink of CH4 in habitats as marine sediments. But, few studies focused on AMO in landfills which may be an important sink of CH4 derived from waste fermentation. To show evidence of AMO and to uncover function anaerobic methanotroph (ANME) community in landfill, different age waste samples were collected in Jinqianpu landfill located in north China. Through high-throughput sequencing, Methanomicrobiales and Methanosarcinales archaea associated with ANME and reverse methanogenic archaea of Methanosarcina and Methanobacterium were detected. Sulfate-reducing bacteria (SRB) (Desulfobulbus and Desulfococcus) which could couple with ANME-conducting AMO were also found. But, the community structure of ANME had no significant difference with depths. From the results of investigation, we can come to a conclusion that sulfate-dependent anaerobic methane oxidation (SR-DAMO) would be the dominant AMO process in the landfill, while iron-dependent anaerobic methane oxidation (M/IR-DAMO) process was weak though concentration of ferric iron was large in the landfill. Denitrification-dependent anaerobic methane oxidation (NR-DAMO) was negative because of lack of nitrate and relevant function microorganisms in the landfill. Results also indicate that CH4 mitigation would have higher potential by increasing electron acceptor contents and promoting the growth of relevant function microorganisms.

Diversity and community structure of marine microbes around the Benham Rise underwater plateau, northeastern Philippines.

Science.gov (United States)

Gajigan, Andrian P; Yñiguez, Aletta T; Villanoy, Cesar L; San Diego-McGlone, Maria Lourdes; Jacinto, Gil S; Conaco, Cecilia

2018-01-01

Microbes are central to the structuring and functioning of marine ecosystems. Given the remarkable diversity of the ocean microbiome, uncovering marine microbial taxa remains a fundamental challenge in microbial ecology. However, there has been little effort, thus far, to describe the diversity of marine microorganisms in the region of high marine biodiversity around the Philippines. Here, we present data on the taxonomic diversity of bacteria and archaea in Benham Rise, Philippines, Western Pacific Ocean, using 16S V4 rRNA gene sequencing. The major bacterial and archaeal phyla identified in the Benham Rise are Proteobacteria, Cyanobacteria, Actinobacteria, Bacteroidetes, Marinimicrobia, Thaumarchaeota and, Euryarchaeota. The upper mesopelagic layer exhibited greater microbial diversity and richness compared to surface waters. Vertical zonation of the microbial community is evident and may be attributed to physical stratification of the water column acting as a dispersal barrier. Canonical Correspondence Analysis (CCA) recapitulated previously known associations of taxa and physicochemical parameters in the environment, such as the association of oligotrophic clades with low nutrient surface water and deep water clades that have the capacity to oxidize ammonia or nitrite at the upper mesopelagic layer. These findings provide foundational information on the diversity of marine microbes in Philippine waters. Further studies are warranted to gain a more comprehensive picture of microbial diversity within the region.

Archaea Dominate the Ammonia-Oxidizing Community in the Rhizosphere of the Freshwater Macrophyte Littorella uniflora

DEFF Research Database (Denmark)

Herrmann, Martina; Saunders, Aaron M.; Schramm, Andreas

2008-01-01

Archaeal and bacterial ammonia monooxygenase genes (amoA) had similar low relative abundances in freshwater sediment. In the rhizosphere of the submersed macrophyte Littorella uniflora, archaeal amoA was 500- to >8,000-fold enriched compared to bacterial amoA, suggesting that the enhanced nitrifi...

Wastewater treatment plant effluents change abundance and composition of ammonia-oxidizing microorganisms in mediterranean urban stream biofilms.

Science.gov (United States)

Merbt, Stephanie N; Auguet, Jean-Christophe; Blesa, Alba; Martí, Eugènia; Casamayor, Emilio O

2015-01-01

Streams affected by wastewater treatment plant (WWTP) effluents are hotspots of nitrification. We analyzed the influence of WWTP inputs on the abundance, distribution, and composition of epilithic ammonia-oxidizing (AO) assemblages in five Mediterranean urban streams by qPCR and amoA gene cloning and sequencing of both archaea (AOA) and bacteria (AOB). The effluents significantly modified stream chemical parameters, and changes in longitudinal profiles of both NH(4)(+) and NO(3)(-) indicated stimulated nitrification activity. WWTP effluents were an allocthonous source of both AOA, essentially from the Nitrosotalea cluster, and mostly of AOB, mainly Nitrosomonas oligotropha, Nitrosomonas communis, and Nitrosospira spp. changing the relative abundance and the natural composition of AO assemblages. Under natural conditions, Nitrososphaera and Nitrosopumilus AOA dominated AO assemblages, and AOB were barely detected. After the WWTP perturbation, epilithic AOB increased by orders of magnitude whereas AOA did not show quantitative changes but a shift in population composition to dominance of Nitrosotalea spp. The foraneous AOB successfully settled in downstream biofilms and probably carried out most of the nitrification activity. Nitrosotalea were only observed downstream and only in biofilms exposed to either darkness or low irradiance. In addition to other potential environmental limitations for AOA distribution, this result suggests in situ photosensitivity as previously reported for Nitrosotalea under laboratory conditions.

Optimization of Pt-Ir on carbon fiber paper for the electro-oxidation of ammonia in alkaline media

International Nuclear Information System (INIS)

Boggs, Bryan K.; Botte, Gerardine G.

2010-01-01

Plating bath concentrations of Pt(IV) and Ir(III) have been optimized as well as the total catalytic loading of bimetallic Pt-Ir alloy for the electro-oxidation of ammonia in alkaline media at standard conditions. This was accomplished using cyclic voltammetry, scanning electron microscopy (SEM), energy dispersive X-ray (EDX), and statistical optimization tools. Concentrations of Pt(IV) and Ir(III) of the plating bath strongly influence electrode surface atomic compositions of the Pt-Ir alloy directly affecting the electro-oxidation behavior of ammonia. Several anode materials were studied using cyclic voltammetry, which demonstrated that Pt-Ir was the most active catalyst for the electro-oxidation of ammonia. Criteria for optimization were minimizing the climatic oxidation overpotential for ammonia and maximizing the exchange current density. Optimized bath composition was found to be 8.844 ± 0.001 g L -1 Pt(IV) and 4.112 ± 0.001 g L -1 Ir(III) based on electrochemical techniques. Physical characterization of the electrodes by SEM indicates that the plating bath concentrations of Pt and Ir influence the growth and deposition behavior of the alloy.

Continuous measurements of ammonia, nitrous oxide and methane from air scrubbers at pig housing facilities.

Science.gov (United States)

Van der Heyden, C; Brusselman, E; Volcke, E I P; Demeyer, P

2016-10-01

Ammonia, largely emitted by agriculture, involves a great risk for eutrophication and acidification leading to biodiversity loss. Air scrubbers are widely applied to reduce ammonia emission from pig and poultry housing facilities, but it is not always clear whether their performance meets the requirements. Besides, there is a growing international concern for the livestock related greenhouse gases methane and nitrous oxide but hardly any data concerning their fate in air scrubbers are available. This contribution presents the results from measurement campaigns conducted at a chemical, a biological and a two-stage biological air scrubber installed at pig housing facilities in Flanders. Ammonia, nitrous oxide and methane at the inlet and outlet of the air scrubbers were monitored on-line during one week using a photoacoustic gas monitor, which allowed to investigate diurnal fluctuations in the removal performance of air scrubbers. Additionally, the homogeneity of the air scrubbers, normally checked by gas detection tubes, was investigated in more detail using the continuous data. The biological air scrubber with extra nitrification tank performed well in terms of ammonia removal (86 ± 6%), while the two-stage air scrubber suffered from nitrifying bacteria inhibition. In the chemical air scrubber the pH was not kept constant, lowering the ammonia removal efficiency. A lower ammonia removal efficiency was found during the day, when the ventilation rate was the highest. Nitrous oxide was produced inside the biological and two-stage scrubber, resulting in an increased outlet concentration of more than 200%. Methane could not be removed in the different air scrubbers because of its low water solubility. Copyright © 2016 Elsevier Ltd. All rights reserved.

Indium oxide thin film based ammonia gas and ethanol vapour sensor

Indian Academy of Sciences (India)

Unknown

acetone and dried under an electric lamp (100 W). Thin films of indium oxide ... A λ-19, UV–VIS Spectrophotometer (Perkin Elmer, USA) was used for measuring .... tion of ammonia is observed through glowing of LED. LM3914, LED driver is ...

Thermophilic archaea activate butane via alkyl-coenzyme M formation.

Science.gov (United States)

Laso-Pérez, Rafael; Wegener, Gunter; Knittel, Katrin; Widdel, Friedrich; Harding, Katie J; Krukenberg, Viola; Meier, Dimitri V; Richter, Michael; Tegetmeyer, Halina E; Riedel, Dietmar; Richnow, Hans-Hermann; Adrian, Lorenz; Reemtsma, Thorsten; Lechtenfeld, Oliver J; Musat, Florin

2016-11-17

The anaerobic formation and oxidation of methane involve unique enzymatic mechanisms and cofactors, all of which are believed to be specific for C 1 -compounds. Here we show that an anaerobic thermophilic enrichment culture composed of dense consortia of archaea and bacteria apparently uses partly similar pathways to oxidize the C 4 hydrocarbon butane. The archaea, proposed genus 'Candidatus Syntrophoarchaeum', show the characteristic autofluorescence of methanogens, and contain highly expressed genes encoding enzymes similar to methyl-coenzyme M reductase. We detect butyl-coenzyme M, indicating archaeal butane activation analogous to the first step in anaerobic methane oxidation. In addition, Ca. Syntrophoarchaeum expresses the genes encoding β-oxidation enzymes, carbon monoxide dehydrogenase and reversible C 1 methanogenesis enzymes. This allows for the complete oxidation of butane. Reducing equivalents are seemingly channelled to HotSeep-1, a thermophilic sulfate-reducing partner bacterium known from the anaerobic oxidation of methane. Genes encoding 16S rRNA and methyl-coenzyme M reductase similar to those identifying Ca. Syntrophoarchaeum were repeatedly retrieved from marine subsurface sediments, suggesting that the presented activation mechanism is naturally widespread in the anaerobic oxidation of short-chain hydrocarbons.

Taxonomic, phylogenetic, and ecological diversity of methanogenic Archaea

Energy Technology Data Exchange (ETDEWEB)

Garcia, J.-L.; Ollivier, B. [Universite de Provence, Marseille (France). Laboratoire de Microbiologist; Patel, B.K.C. [Griffith University, Brisbane (Australia). Microbial Discovery Research Unit

2000-07-01

Methanogens are strict anaerobes which share a complex biochemistry for methane synthesis as part of their energy metabolism. The discovery of the unique biochemical and genetic properties of these organisms led to the concept of Archaebacteria at the end of the seventies and the proposal in 1990 for the domain Archaea. A number of studies have provided evidence that they are of economic value. The successive petroleum crisis since 1973 has led to great interest in alternative forms of energy, including recovery of methane via anaerobic digestion of wastes. Improvements in the design of digestors have been made possible by advances in understanding the ecology and physiology of methanogens. In the cattle industry, the knowledge of the fermentation processes in the rumen demonstrated a net loss of energy via the methanogenesis, and inhibitors such as Rumensin have been developed to enhance meat yields. Oil companies try to distinguish between natural gas produced by methanogens or by the thermocatalytic reactions associated with petroleum generation. Finally, studies on the global distribution of methane in the earth's atmosphere are increasing due to the sudden awareness of its possible role in the enhancement of the greenhouse effect from CO-2 accumulation, and on the reversal of stratospheric ozone depletion. This paper summarizes the recent knowledge of methanogenic Archaea with emphasis on their taxonomy and ecology. (author)

Effect of communities of ammonia-oxidizing bacteria on degradation of 17-alpha-ethynylestradiol by nitrifying activated sludge

Energy Technology Data Exchange (ETDEWEB)

Limpiyakorn, T.; Sermwaraphan, P.; Kurisu, F.

2009-07-01

An endocrine disrupting compound, 17-alpha-ethynylestradiol (EE2), is a synthetic estrogen used as a key ingredient in oral contraceptives pill. this persistent organic pollutant, no biodegradable by most microorganisms, is discharged via municipal waste streams to natural receiving waters. Recently, it was found that ammonia-oxidizing bacteria (AOB) in nitrifying activated sludge (NAS) enriched with high ammonium loads can degrade EE2 via co-metabolism during ammonia oxidation. (Author)

Ammonia modification of activated carbon to enhance carbon dioxide adsorption: Effect of pre-oxidation

Science.gov (United States)

Shafeeyan, Mohammad Saleh; Daud, Wan Mohd Ashri Wan; Houshmand, Amirhossein; Arami-Niya, Arash

2011-02-01

A commercial granular activated carbon (GAC) was subjected to thermal treatment with ammonia for obtaining an efficient carbon dioxide (CO2) adsorbent. In general, CO2 adsorption capacity of activated carbon can be increased by introduction of basic nitrogen functionalities onto the carbon surface. In this work, the effect of oxygen surface groups before introduction of basic nitrogen functionalities to the carbon surface on CO2 adsorption capacity was investigated. For this purpose two different approaches of ammonia treatment without preliminary oxidation and amination of oxidized samples were studied. Modified carbons were characterized by elemental analysis and Fourier Transform Infrared spectroscopy (FT-IR) to study the impact of changes in surface chemistry and formation of specific surface groups on adsorption properties. The texture of the samples was characterized by conducting N2 adsorption/desorption at -196 °C. CO2 capture performance of the samples was investigated using a thermogravimetric analysis (TGA). It was found that in both modification techniques, the presence of nitrogen functionalities on carbon surface generally increased the CO2 adsorption capacity. The results indicated that oxidation followed by high temperature ammonia treatment (800 °C) considerably enhanced the CO2 uptake at higher temperatures.

3,4-Dimethylpyrazole phosphate (DMPP) reduces activity of ammonia oxidizers without adverse effects on non-target soil microorganisms and functions

DEFF Research Database (Denmark)

Kong, Xianwang; Duan, Yun-Feng (Kevin); Schramm, Andreas

2016-01-01

, dehydrogenase activity, phospholipid fatty acid composition and potential ammonia oxidation. DMPP showed no significant nontarget effects (p > 0.05), but a possible stress response in HD was indicated by a factor analysis of phospholipid fatty acid composition. There was a strong DMPP inhibition on potential...... of ammonia oxidation. We investigated effects of DMPP amendment equivalent to 0 (Control), 1 (regular dose, RD) or 10 (high dose, HD) kg ha1 in a sandy loam grassland soil at 50% water-filled pore space. Following incubation for 1, 7 or 14 d, soil was analyzed for fluorescein diacetate hydrolysis...... ammonia oxidation which was still significant (p HD after 14 d. In separate treatments receiving 50 mg NH4 +-N kg1 dry soil in addition to DMPP, the inhibition of nitrate accumulation was similar in RD and HD at around 75%. Abundances of the gene amoA from ammonia oxidizing bacteria (AOB...

Methane-Fueled Syntrophy through Extracellular Electron Transfer: Uncovering the Genomic Traits Conserved within Diverse Bacterial Partners of Anaerobic Methanotrophic Archaea.

Science.gov (United States)

Skennerton, Connor T; Chourey, Karuna; Iyer, Ramsunder; Hettich, Robert L; Tyson, Gene W; Orphan, Victoria J

2017-08-01

The anaerobic oxidation of methane by anaerobic methanotrophic (ANME) archaea in syntrophic partnership with deltaproteobacterial sulfate-reducing bacteria (SRB) is the primary mechanism for methane removal in ocean sediments. The mechanism of their syntrophy has been the subject of much research as traditional intermediate compounds, such as hydrogen and formate, failed to decouple the partners. Recent findings have indicated the potential for extracellular electron transfer from ANME archaea to SRB, though it is unclear how extracellular electrons are integrated into the metabolism of the SRB partner. We used metagenomics to reconstruct eight genomes from the globally distributed SEEP-SRB1 clade of ANME partner bacteria to determine what genomic features are required for syntrophy. The SEEP-SRB1 genomes contain large multiheme cytochromes that were not found in previously described free-living SRB and also lack periplasmic hydrogenases that may prevent an independent lifestyle without an extracellular source of electrons from ANME archaea. Metaproteomics revealed the expression of these cytochromes at in situ methane seep sediments from three sites along the Pacific coast of the United States. Phylogenetic analysis showed that these cytochromes appear to have been horizontally transferred from metal-respiring members of the Deltaproteobacteria such as Geobacter and may allow these syntrophic SRB to accept extracellular electrons in place of other chemical/organic electron donors. IMPORTANCE Some archaea, known as anaerobic methanotrophs, are capable of converting methane into carbon dioxide when they are growing syntopically with sulfate-reducing bacteria. This partnership is the primary mechanism for methane removal in ocean sediments; however, there is still much to learn about how this syntrophy works. Previous studies have failed to identify the metabolic intermediate, such as hydrogen or formate, that is passed between partners. However, recent analysis of

Intensive Ammonia and Methane Oxidation in Organic Liquid Manure Crusts

DEFF Research Database (Denmark)

Nielsen, Daniel Aagren; Nielsen, Lars Peter; Schramm, Andreas

methane oxidizing bacteria (MOB) and are known to accumulate nitrite and nitrate, indicating the presence of ammonia oxidizers (AOB). We have surveyed six manure tanks with organic covers to investigate the prevalence of MOB and AOB and to link the potential activity with physical and chemical aspects...... characterized with respect to O2 availability by in situ profiling with electrochemical microsensors. Results show that oxygen penetration increased from few micrometers up to several centimetres with crust age. AOB and ammonium oxidation are ubiquitously present in well-developed manure crusts whereas MOB were...... also CH4 emission mitigation, an organic surface crust can be effective if populations of MOB and AOB are allowed to build up....

AMMONIA REMOVAL AND NITROUS OXIDE PRODUCTION IN GAS-PHASE COMPOST BIOFILTERS

Science.gov (United States)

Biofiltration technology is widely utilized for treating ammonia gas (NH3), with one of its potential detrimental by-products being nitrous oxide (N2O), a greenhouse gas approximately 300 times more reactive to infrared than CO2. The present work intends to provide the relation between NH3 removal d...

Methanogenic archaea

International Nuclear Information System (INIS)

Joblin, K.N.

2005-01-01

This chapter outlines procedures for enumerating, isolating, culturing and storing methanogens from ruminal digesta. The methanogens, a large and diverse group of Archaea, have unique features that separate them from the bacteria and the eukaryotes. They are the only recognized ruminal microbes belonging to the Archaea and are an integral part of the rumen microbial ecosystem. By scavenging hydrogen gas, methanogens play a key ecological role in keeping the partial pressure of hydrogen low so that fermentation can proceed efficiently. Although about 70 methanogenic species belonging to 2 1 genera have been identified from anaerobic environments, and a range of different methanogens co-exist in the rumen, to date only seven ruminal species have been isolated and purified. The population densities of methanogens in the rumen appear to be influenced by diet, and in particular by the fibre content of the diet. Sheep and cattle fed diets rich in concentrates contained 10 7 -10 8 and 10 8 - 10 9 ruminal methanogens/g, respectively, whereas sheep and dairy cows grazing pasture contained 10 9 -10 10 ruminal methanogens/g (G.N. Jarvis and K.N. Joblin, unpublished data). With careful application, methanogen population densities can readily be determined using culture methods. These appear to be similar to the population densities determined by culture-independent methods (P. Evans and K.N. Joblin, unpublished data)

Archaea, Bacteria, and Sulfur-Cycling in a Shallow-Sea Hydrothermal Ecosystem

Science.gov (United States)

Amend, J. P.; Huang, C.; Amann, R.; Bach, W.; Meyerdierks, A.; Price, R. E.; Schubotz, F.; Summons, R. E.; Wenzhoefer, F.

2009-12-01

Deep-sea hydrothermal systems are windows to the marine subsurface biosphere. It often is overlooked, however, that their far more accessible shallow-sea counterparts can serve the same purpose. To characterize the extent, diversity, and activity of the subsurface microbial community in the shallow vent ecosystem near Panarea Island (Italy), sediment cores were analyzed with a broad array of analytical techniques. Vent fluid and sediment temperatures reached up to 135 °C, with pHs in porewaters generally measuring 5-6. Microsensor profiles marked a very sharp oxic-anoxic transition, and when coupled to pH and H2S profiles, pointed to aerobic sulfide oxidation. With increasing depth from the sediment-water interface, porewater analyses showed a decrease in sulfate levels from ~30 mM to thermophilic sulfate reducing and acidophilic sulfide oxidizing bacteria. Results from several sites also showed that with increasing depth and temperature, biomass abundance of archaea generally increased relative to that of bacteria. Lastly, DGGE fingerprinting and 16S rRNA clone libraries from several depths at Hot Lake revealed a moderate diversity of bacteria, dominated by Epsilonproteobacteria; this class is known to catalyze both sulfur reduction and oxidation reactions, and to mediate the formation of iron-sulfides, including framboidal pyrite. Archaeal sequences at Hot Lake are dominated by uncultured Thermoplasmatales, plus several sequences in the Korarchaeota.

Trace Metal Requirements for Microbial Enzymes Involved in the Production and Consumption of Methane and Nitrous Oxide

Science.gov (United States)

Glass, Jennifer B.; Orphan, Victoria J.

2011-01-01

Fluxes of greenhouse gases to the atmosphere are heavily influenced by microbiological activity. Microbial enzymes involved in the production and consumption of greenhouse gases often contain metal cofactors. While extensive research has examined the influence of Fe bioavailability on microbial CO2 cycling, fewer studies have explored metal requirements for microbial production and consumption of the second- and third-most abundant greenhouse gases, methane (CH4), and nitrous oxide (N2O). Here we review the current state of biochemical, physiological, and environmental research on transition metal requirements for microbial CH4 and N2O cycling. Methanogenic archaea require large amounts of Fe, Ni, and Co (and some Mo/W and Zn). Low bioavailability of Fe, Ni, and Co limits methanogenesis in pure and mixed cultures and environmental studies. Anaerobic methane oxidation by anaerobic methanotrophic archaea (ANME) likely occurs via reverse methanogenesis since ANME possess most of the enzymes in the methanogenic pathway. Aerobic CH4 oxidation uses Cu or Fe for the first step depending on Cu availability, and additional Fe, Cu, and Mo for later steps. N2O production via classical anaerobic denitrification is primarily Fe-based, whereas aerobic pathways (nitrifier denitrification and archaeal ammonia oxidation) require Cu in addition to, or possibly in place of, Fe. Genes encoding the Cu-containing N2O reductase, the only known enzyme capable of microbial N2O conversion to N2, have only been found in classical denitrifiers. Accumulation of N2O due to low Cu has been observed in pure cultures and a lake ecosystem, but not in marine systems. Future research is needed on metalloenzymes involved in the production of N2O by enrichment cultures of ammonia oxidizing archaea, biological mechanisms for scavenging scarce metals, and possible links between metal bioavailability and greenhouse gas fluxes in anaerobic environments where metals may be limiting due to sulfide

Geoarchaeota: a new candidate phylum in the Archaea from high-temperature acidic iron mats in Yellowstone National Park.

Science.gov (United States)

Kozubal, Mark A; Romine, Margaret; Jennings, Ryan deM; Jay, Zack J; Tringe, Susannah G; Rusch, Doug B; Beam, Jacob P; McCue, Lee Ann; Inskeep, William P

2013-03-01

Geothermal systems in Yellowstone National Park (YNP) provide an outstanding opportunity to understand the origin and evolution of metabolic processes necessary for life in extreme environments including low pH, high temperature, low oxygen and elevated concentrations of reduced iron. Previous phylogenetic studies of acidic ferric iron mats from YNP have revealed considerable diversity of uncultivated and undescribed archaea. The goal of this study was to obtain replicate de novo genome assemblies for a dominant archaeal population inhabiting acidic iron-oxide mats in YNP. Detailed analysis of conserved ribosomal and informational processing genes indicates that the replicate assemblies represent a new candidate phylum within the domain Archaea referred to here as 'Geoarchaeota' or 'novel archaeal group 1 (NAG1)'. The NAG1 organisms contain pathways necessary for the catabolism of peptides and complex carbohydrates as well as a bacterial-like Form I carbon monoxide dehydrogenase complex likely used for energy conservation. Moreover, this novel population contains genes involved in the metabolism of oxygen including a Type A heme copper oxidase, a bd-type terminal oxidase and a putative oxygen-sensing protoglobin. NAG1 has a variety of unique bacterial-like cofactor biosynthesis and transport genes and a Type3-like CRISPR system. Discovery of NAG1 is critical to our understanding of microbial community structure and function in extant thermophilic iron-oxide mats of YNP, and will provide insight regarding the evolution of Archaea in early Earth environments that may have important analogs active in YNP today.

Influence of additives on selective noncatalytic reduction of nitric oxide with ammonia in circulating fluidized bed boilers

DEFF Research Database (Denmark)

Leckner, Bo; Karlsson, Maria; Dam-Johansen, Kim

1991-01-01

The application of selective noncatalytic reduction of nitric oxide with ammonia in circulating fluidized bed boilers is investigated. Special attention is directed to the use of additives to the ammonia so that the efficiency of the NO reduction at lower temperatures can be increased. Tests under...

Human age and skin physiology shape diversity and abundance of Archaea on skin.

Science.gov (United States)

Moissl-Eichinger, Christine; Probst, Alexander J; Birarda, Giovanni; Auerbach, Anna; Koskinen, Kaisa; Wolf, Peter; Holman, Hoi-Ying N

2017-06-22

The human skin microbiome acts as an important barrier protecting our body from pathogens and other environmental influences. Recent investigations have provided evidence that Archaea are a constant but highly variable component of the human skin microbiome, yet factors that determine their abundance changes are unknown. Here, we tested the hypothesis that the abundance of archaea on human skin is influenced by human age and skin physiology by quantitative PCR of 51 different skin samples taken from human subjects of various age. Our results reveal that archaea are more abundant in human subjects either older than 60 years or younger than 12 years as compared to middle-aged human subjects. These results, together with results obtained from spectroscopy analysis, allowed us gain first insights into a potential link of lower sebum levels and lipid content and thus reduced skin moisture with an increase in archaeal signatures. Amplicon sequencing of selected samples revealed the prevalence of specific eury- and mainly thaumarchaeal taxa, represented by a core archaeome of the human skin.

Bioaugmentation of Syntrophic Acetate-Oxidizing Culture in Biogas Reactors Exposed to Increasing Levels of Ammonia

Science.gov (United States)

Westerholm, Maria; Levén, Lotta

2012-01-01

The importance of syntrophic acetate oxidation for process stability in methanogenic systems operating at high ammonia concentrations has previously been emphasized. In this study we investigated bioaugmentation of syntrophic acetate-oxidizing (SAO) cultures as a possible method for decreasing the adaptation period of biogas reactors operating at gradually increased ammonia concentrations (1.5 to 11 g NH4+-N/liter). Whole stillage and cattle manure were codigested semicontinuously for about 460 days in four mesophilic anaerobic laboratory-scale reactors, and a fixed volume of SAO culture was added daily to two of the reactors. Reactor performance was evaluated in terms of biogas productivity, methane content, pH, alkalinity, and volatile fatty acid (VFA) content. The decomposition pathway of acetate was analyzed by isotopic tracer experiments, and population dynamics were monitored by quantitative PCR analyses. A shift in dominance from aceticlastic methanogenesis to SAO occurred simultaneously in all reactors, indicating no influence by bioaugmentation on the prevailing pathway. Higher abundances of Clostridium ultunense and Tepidanaerobacter acetatoxydans were associated with bioaugmentation, but no influence on Syntrophaceticus schinkii or the methanogenic population was distinguished. Overloading or accumulation of VFA did not cause notable dynamic effects on the population. Instead, the ammonia concentration had a substantial impact on the abundance level of the microorganisms surveyed. The addition of SAO culture did not affect process performance or stability against ammonia inhibition, and all four reactors deteriorated at high ammonia concentrations. Consequently, these findings further demonstrate the strong influence of ammonia on the methane-producing consortia and on the representative methanization pathway in mesophilic biogas reactors. PMID:22923397

Inhibitory effects of C2 to C10 1-alkynes on ammonia oxidation in two Nitrososphaera species.

Science.gov (United States)

Taylor, A E; Taylor, K; Tennigkeit, B; Palatinszky, M; Stieglmeier, M; Myrold, D D; Schleper, C; Wagner, M; Bottomley, P J

2015-03-01

A previous study showed that ammonia oxidation by the Thaumarchaeota Nitrosopumilus maritimus (group 1.1a) was resistant to concentrations of the C8 1-alkyne, octyne, which completely inhibits activity by ammonia-oxidizing bacteria. In this study, the inhibitory effects of octyne and other C2 to C10 1-alkynes were evaluated on the nitrite production activity of two pure culture isolates from Thaumarchaeota group 1.1b, Nitrososphaera viennensis strain EN76 and Nitrososphaera gargensis. Both N. viennensis and N. gargensis were insensitive to concentrations of octyne that cause complete and irreversible inactivation of nitrite production by ammonia-oxidizing bacteria. However, octyne concentrations (≥20 μM) that did not inhibit N. maritimus partially inhibited nitrite production in N. viennensis and N. gargensis in a manner that did not show the characteristics of irreversible inactivation. In contrast to previous studies with an ammonia-oxidizing bacterium, Nitrosomonas europaea, octyne inhibition of N. viennensis was: (i) fully and immediately reversible, (ii) not competitive with NH4 (+), and (iii) without effect on the competitive interaction between NH4 (+) and acetylene. Both N. viennensis and N. gargensis demonstrated the same overall trend in regard to 1-alkyne inhibition as previously observed for N. maritimus, being highly sensitive to ≤C5 alkynes and more resistant to longer-chain length alkynes. Reproducible differences were observed among N. maritimus, N. viennensis, and N. gargensis in regard to the extent of their resistance/sensitivity to C6 and C7 1-alkynes, which may indicate differences in the ammonia monooxygenase binding and catalytic site(s) among the Thaumarchaeota. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

Diversity of membrane transport proteins for vitamins in bacteria and archaea

NARCIS (Netherlands)

Jähme, Michael; Slotboom, Dirk Jan

BACKGROUND: All organisms use cofactors to extend the catalytic capacities of proteins. Many bacteria and archaea can synthesize cofactors from primary metabolites, but there are also prokaryotes that do not have the complete biosynthetic pathways for all essential cofactors. These organisms are

A Ferredoxin- and F420H2-Dependent, Electron-Bifurcating, Heterodisulfide Reductase with Homologs in the Domains Bacteria and Archaea.

Science.gov (United States)

Yan, Zhen; Wang, Mingyu; Ferry, James G

2017-02-07

Heterodisulfide reductases (Hdr) of the HdrABC class are ancient enzymes and a component of the anaerobic core belonging to the prokaryotic common ancestor. The ancient origin is consistent with the widespread occurrence of genes encoding putative HdrABC homologs in metabolically diverse prokaryotes predicting diverse physiological functions; however, only one HdrABC has been characterized and that was from a narrow metabolic group of obligate CO 2 -reducing methanogenic anaerobes (methanogens) from the domain Archaea Here we report the biochemical characterization of an HdrABC homolog (HdrA2B2C2) from the acetate-utilizing methanogen Methanosarcina acetivorans with unusual properties structurally and functionally distinct from the only other HdrABC characterized. Homologs of the HdrA2B2C2 archetype are present in phylogenetically and metabolically diverse species from the domains Bacteria and Archaea The expression of the individual HdrA2, HdrB2, and HdrB2C2 enzymes in Escherichia coli, and reconstitution of an active HdrA2B2C2 complex, revealed an intersubunit electron transport pathway dependent on ferredoxin or coenzyme F 420 (F 420 H 2 ) as an electron donor. Remarkably, HdrA2B2C2 couples the previously unknown endergonic oxidation of F 420 H 2 and reduction of ferredoxin with the exergonic oxidation of F 420 H 2 and reduction of the heterodisulfide of coenzyme M and coenzyme B (CoMS-SCoB). The unique electron bifurcation predicts a role for HdrA2B2C2 in Fe(III)-dependent anaerobic methane oxidation (ANME) by M. acetivorans and uncultured species from ANME environments. HdrA2B2C2, ubiquitous in acetotrophic methanogens, was shown to participate in electron transfer during acetotrophic growth of M. acetivorans and proposed to be essential for growth in the environment when acetate is limiting. Discovery of the archetype HdrA2B2C2 heterodisulfide reductase with categorically unique properties extends the understanding of this ancient family beyond CO 2

Bacterial, Archaeal, and Eukaryotic Diversity across Distinct Microhabitats in an Acid Mine Drainage

Science.gov (United States)

Mesa, Victoria; Gallego, Jose L. R.; González-Gil, Ricardo; Lauga, Béatrice; Sánchez, Jesús; Méndez-García, Celia; Peláez, Ana I.

2017-01-01

Acid mine drainages are characterized by their low pH and the presence of dissolved toxic metallic species. Microorganisms survive in different microhabitats within the ecosystem, namely water, sediments, and biofilms. In this report, we surveyed the microbial diversity within all domains of life in the different microhabitats at Los Rueldos abandoned mercury underground mine (NW Spain), and predicted bacterial function based on community composition. Sediment samples contained higher proportions of soil bacteria (AD3, Acidobacteria), as well as Crenarchaeota and Methanomassiliicoccaceae archaea. Oxic and hypoxic biofilm samples were enriched in bacterial iron oxidizers from the genus Leptospirillum, order Acidithiobacillales, class Betaproteobacteria, and archaea from the class Thermoplasmata. Water samples were enriched in Cyanobacteria and Thermoplasmata archaea at a 3–98% of the sunlight influence, whilst Betaproteobacteria, Thermoplasmata archaea, and Micrarchaea dominated in acid water collected in total darkness. Stalactites hanging from the Fe-rich mine ceiling were dominated by the neutrophilic iron oxidizer Gallionella and other lineages that were absent in the rest of the microhabitats (e.g., Chlorobi, Chloroflexi). Eukaryotes were detected in biofilms and open-air water samples, and belonged mainly to clades SAR (Alveolata and Stramenopiles), and Opisthokonta (Fungi). Oxic and hypoxic biofilms displayed higher proportions of ciliates (Gonostomum, Oxytricha), whereas water samples were enriched in fungi (Paramicrosporidium and unknown microbial Helotiales). Predicted function through bacterial community composition suggested adaptive evolutive convergence of function in heterogeneous communities. Our study showcases a broad description of the microbial diversity across different microhabitats in the same environment and expands the knowledge on the diversity of microbial eukaryotes in AMD habitats. PMID:28955322

Bacterial, Archaeal, and Eukaryotic Diversity across Distinct Microhabitats in an Acid Mine Drainage

Directory of Open Access Journals (Sweden)

Victoria Mesa

2017-09-01

Full Text Available Acid mine drainages are characterized by their low pH and the presence of dissolved toxic metallic species. Microorganisms survive in different microhabitats within the ecosystem, namely water, sediments, and biofilms. In this report, we surveyed the microbial diversity within all domains of life in the different microhabitats at Los Rueldos abandoned mercury underground mine (NW Spain, and predicted bacterial function based on community composition. Sediment samples contained higher proportions of soil bacteria (AD3, Acidobacteria, as well as Crenarchaeota and Methanomassiliicoccaceae archaea. Oxic and hypoxic biofilm samples were enriched in bacterial iron oxidizers from the genus Leptospirillum, order Acidithiobacillales, class Betaproteobacteria, and archaea from the class Thermoplasmata. Water samples were enriched in Cyanobacteria and Thermoplasmata archaea at a 3–98% of the sunlight influence, whilst Betaproteobacteria, Thermoplasmata archaea, and Micrarchaea dominated in acid water collected in total darkness. Stalactites hanging from the Fe-rich mine ceiling were dominated by the neutrophilic iron oxidizer Gallionella and other lineages that were absent in the rest of the microhabitats (e.g., Chlorobi, Chloroflexi. Eukaryotes were detected in biofilms and open-air water samples, and belonged mainly to clades SAR (Alveolata and Stramenopiles, and Opisthokonta (Fungi. Oxic and hypoxic biofilms displayed higher proportions of ciliates (Gonostomum, Oxytricha, whereas water samples were enriched in fungi (Paramicrosporidium and unknown microbial Helotiales. Predicted function through bacterial community composition suggested adaptive evolutive convergence of function in heterogeneous communities. Our study showcases a broad description of the microbial diversity across different microhabitats in the same environment and expands the knowledge on the diversity of microbial eukaryotes in AMD habitats.

Molecular diversity of the ammonia-oxidizing bacteria community in disused tin-mining ponds located within Kampar, Perak, Malaysia.

Science.gov (United States)

Sow, S L S; Khoo, G; Chong, L K; Smith, T J; Harrison, P L; Ong, H K A

2014-02-01

Disused tin-mining ponds make up a significant amount of water bodies in Malaysia particularly at the Kinta Valley in the state of Perak where tin-mining activities were the most extensive, and these abundantly available water sources are widely used in the field of aquaculture and agriculture. However, the natural ecology and physicochemical conditions of these ponds, many of which have been altered due to secondary post-mining activities, remains to be explored. As ammonia-oxidizing bacteria (AOB) are directly related to the nutrient cycles of aquatic environments and are useful bioindicators of environmental variations, the focus of this study was to identify AOBs associated with disused tin-mining ponds that have a history of different secondary activities in comparison to ponds which were left untouched and remained as part of the landscape. The 16S rDNA gene was used to detect AOBs in the sediment and water sampled from the three types of disused mining ponds, namely ponds without secondary activity, ponds that were used for lotus cultivation and post-aquaculture ponds. When the varying pond types were compared with the sequence and phylogenetic analysis of the AOB clone libraries, both Nitrosomonas and Nitrosospira-like AOB were detected though Nitrosospira spp. was seen to be the most ubiquitous AOB as it was present in all ponds types. However, AOBs were not detected in the sediments of idle ponds. Based on rarefaction analysis and diversity indices, the disused mining pond with lotus culture indicated the highest richness of AOBs. Canonical correspondence analysis indicated that among the physicochemical properties of the pond sites, TAN and nitrite were shown to be the main factors that influenced the community structure of AOBs in these disused tin-mining ponds.

Resveratrol prevents ammonia toxicity in astroglial cells.

Directory of Open Access Journals (Sweden)

Larissa Daniele Bobermin

Full Text Available Ammonia is implicated as a neurotoxin in brain metabolic disorders associated with hyperammonemia. Acute ammonia toxicity can be mediated by an excitotoxic mechanism, oxidative stress and nitric oxide (NO production. Astrocytes interact with neurons, providing metabolic support and protecting against oxidative stress and excitotoxicity. Astrocytes also convert excess ammonia and glutamate into glutamine via glutamine synthetase (GS. Resveratrol, a polyphenol found in grapes and red wines, exhibits antioxidant and anti-inflammatory properties and modulates glial functions, such as glutamate metabolism. We investigated the effect of resveratrol on the production of reactive oxygen species (ROS, GS activity, S100B secretion, TNF-α, IL-1β and IL-6 levels in astroglial cells exposed to ammonia. Ammonia induced oxidative stress, decreased GS activity and increased cytokines release, probably by a mechanism dependent on protein kinase A (PKA and extracellular signal-regulated kinase (ERK pathways. Resveratrol prevented ammonia toxicity by modulating oxidative stress, glial and inflammatory responses. The ERK and nuclear factor-κB (NF-κB are involved in the protective effect of resveratrol on cytokines proinflammatory release. In contrast, other antioxidants (e.g., ascorbic acid and trolox were not effective against hyperammonemia. Thus, resveratrol could be used to protect against ammonia-induced neurotoxicity.

Resveratrol Prevents Ammonia Toxicity in Astroglial Cells

Science.gov (United States)

Guerra, Maria Cristina; Leite, Marina Concli; Souza, Diogo Onofre; Gonçalves, Carlos-Alberto; Gottfried, Carmem

2012-01-01

Ammonia is implicated as a neurotoxin in brain metabolic disorders associated with hyperammonemia. Acute ammonia toxicity can be mediated by an excitotoxic mechanism, oxidative stress and nitric oxide (NO) production. Astrocytes interact with neurons, providing metabolic support and protecting against oxidative stress and excitotoxicity. Astrocytes also convert excess ammonia and glutamate into glutamine via glutamine synthetase (GS). Resveratrol, a polyphenol found in grapes and red wines, exhibits antioxidant and anti-inflammatory properties and modulates glial functions, such as glutamate metabolism. We investigated the effect of resveratrol on the production of reactive oxygen species (ROS), GS activity, S100B secretion, TNF-α, IL-1β and IL-6 levels in astroglial cells exposed to ammonia. Ammonia induced oxidative stress, decreased GS activity and increased cytokines release, probably by a mechanism dependent on protein kinase A (PKA) and extracellular signal-regulated kinase (ERK) pathways. Resveratrol prevented ammonia toxicity by modulating oxidative stress, glial and inflammatory responses. The ERK and nuclear factor-κB (NF-κB) are involved in the protective effect of resveratrol on cytokines proinflammatory release. In contrast, other antioxidants (e.g., ascorbic acid and trolox) were not effective against hyperammonemia. Thus, resveratrol could be used to protect against ammonia-induced neurotoxicity. PMID:23284918

Marine Group II Dominates Planktonic Archaea in Water Column of the Northeastern South China Sea

Directory of Open Access Journals (Sweden)

Haodong Liu

2017-06-01

Full Text Available Temperature, nutrients, and salinity are among the important factors constraining the distribution and abundance of microorganisms in the ocean. Marine Group II (MGII belonging to Euryarchaeota commonly dominates the planktonic archaeal community in shallow water and Marine Group I (MGI, now is called Thaumarchaeota in deeper water in global oceans. Results of quantitative PCR (qPCR and 454 sequencing in our study, however, showed the dominance of MGII in planktonic archaea throughout the water column of the northeastern South China Sea (SCS that is characterized by strong water mixing. The abundance of ammonia-oxidizing archaea (AOA representing the main group of Thaumarchaeota in deeper water in the northeastern SCS was significantly lower than in other oceanic regions. Phylogenetic analysis showed that the top operational taxonomic units (OTUs of the MGII occurring predominantly below 200 m depth may be unique in the northeastern SCS based on the observation that they are distantly related to known sequences (identity ranging from 90–94%. The abundance of MGII was also significantly correlated with total bacteria in the whole column, which may indicate that MGII and bacteria may have similar physiological or biochemical properties or responses to environmental variation. This study provides valuable information about the dominance of MGII over AOA in both shallow and deep water in the northeastern SCS and highlights the need for comprehensive studies integrating physical, chemical, and microbial oceanography.

Review of Options for Ammonia/Ammonium Management

Energy Technology Data Exchange (ETDEWEB)

Nash, C. A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

2016-05-06

This report is a review of literature supporting practical ammonia/ammonium destruction processes. Melter research supporting Hanford Low Activity Waste (LAW) glass production has shown that significant amounts of ammonia will be in the melter offgas condensate. Further work with secondary waste forms indicates the potential need to remove the ammonia, perhaps by an oxidative process. This review finds likely practical chemical methods to oxidize ammonia in aqueous solution at moderate temperatures and atmospheric pressure, using easily obtained reagents. Leading candidates include nitrite oxidation to produce nitrogen gas, various peroxide oxidative processes, and air stripping. This work reviews many other processes and provides reasoning to not consider those processes further for this application.

Contribution of crenarchaeal autotrophic ammonia oxidizers to the dark primary production in Tyrrhenian deep waters (Central Mediterranean Sea)

OpenAIRE

Yakimov, Michail M.; La Cono, Violetta; Smedile, Francesco; DeLuca, Thomas H.; Juarez, Silvia; Ciordia, Sergio; Fernandez, Marisol; Albar, Juan Pablo; Ferrer, Manuel; Golyshin, Peter N.; Giuliano, Laura

2011-01-01

Mesophilic Crenarchaeota have recently been thought to be significant contributors to nitrogen (N) and carbon (C) cycling. In this study, we examined the vertical distribution of ammonia-oxidizing Crenarchaeota at offshore site in Southern Tyrrhenian Sea. The median value of the crenachaeal cell to amoA gene ratio was close to one suggesting that virtually all deep-sea Crenarchaeota possess the capacity to oxidize ammonia. Crenarchaea-specific genes, nirK and ureC, for nitrite reductase and u...

THE BIOENERGETICS OF AMMONIA AND HYDROXYLAMINE OXIDATION IN NITROSOMONAS-EUROPAEA AT ACID AND ALKALINE PH

NARCIS (Netherlands)

FRIJLINK, MJ; ABEE, T; LAANBROEK, HJ; DEBOER, W; KONINGS, WN

Autotrophic ammonia oxidizers depend on alkaline or neutral conditions for optimal activity. Below pH 7 growth and metabolic activity decrease dramatically. Actively oxidizing cells of Nitrosomonas europaea do not maintain a constant internal pH when the external pH is varied from 5 to 8. Studies of

Enhanced sulfamethoxazole degradation through ammonia oxidizing bacteria co-metabolism and fate of transformation products.

Science.gov (United States)

Kassotaki, Elissavet; Buttiglieri, Gianluigi; Ferrando-Climent, Laura; Rodriguez-Roda, Ignasi; Pijuan, Maite

2016-05-01

The occurrence of the widely-used antibiotic sulfamethoxazole (SFX) in wastewaters and surface waters has been reported in a large number of studies. However, the results obtained up-to-date have pointed out disparities in its removal. This manuscript explores the enhanced biodegradation potential of an enriched culture of Ammonia Oxidizing Bacteria (AOB) towards SFX. Several sets of batch tests were conducted to establish a link between SFX degradation and specific ammonia oxidation rate. The occurrence, degradation and generation of SFX and some of its transformation products (4-Nitro SFX, Desamino-SFX and N(4)-Acetyl-SFX) was also monitored. A clear link between the degradation of SFX and the nitrification rate was found, resulting in an increased SFX removal at higher specific ammonia oxidation rates. Moreover, experiments conducted under the presence of allylthiourea (ATU) did not present any removal of SFX, suggesting a connection between the AMO enzyme and SFX degradation. Long term experiments (up to 10 weeks) were also conducted adding two different concentrations (10 and 100 μg/L) of SFX in the influent of a partial nitrification sequencing batch reactor, resulting in up to 98% removal. Finally, the formation of transformation products during SFX degradation represented up to 32%, being 4-Nitro-SFX the most abundant. Copyright © 2016 Elsevier Ltd. All rights reserved.

Oxygen Distribution and Potential Ammonia Oxidation in Floating, Liquid Manure Crusts

DEFF Research Database (Denmark)

Nielsen, Daniel Aagren; Nielsen, Lars Peter; Schramm, Andreas

2010-01-01

Floating, organic crusts on liquid manure, stored as a result of animal production, reduce emission of ammonia (NH3) and other volatile compounds during storage. The occurrence of NO2- and NO3- in the crusts indicate the presence of actively metabolizing NH3 oxidizing bacteria (AOB) which may...... be partly responsible for this mitigation effect. Six manure tanks with organic covers (straw and natural) were surveyed to investigate the prevalence and potential activity of AOB and its dependence on the O2 availability in the crust matrix as studied by electrochemical profiling. Oxygen penetration...... microorganisms, including AOB. The microbial activity may thus contribute to a considerable reduction of ammonia emissions from slurry tanks with well-developed crusts....

Respiratory transformation of nitrous oxide (N2O) to dinitrogen by Bacteria and Archaea.

Science.gov (United States)

Zumft, Walter G; Kroneck, Peter M H

2007-01-01

N2O is a potent greenhouse gas and stratospheric reactant that has been steadily on the rise since the beginning of industrialization. It is an obligatory inorganic metabolite of denitrifying bacteria, and some production of N2O is also found in nitrifying and methanotrophic bacteria. We focus this review on the respiratory aspect of N2O transformation catalysed by the multicopper enzyme nitrous oxide reductase (N2OR) that provides the bacterial cell with an electron sink for anaerobic growth. Two types of Cu centres discovered in N2OR were both novel structures among the Cu proteins: the mixed-valent dinuclear Cu(A) species at the electron entry site of the enzyme, and the tetranuclear Cu(Z) centre as the first catalytically active Cu-sulfur complex known. Several accessory proteins function as Cu chaperone and ABC transporter systems for the biogenesis of the catalytic centre. We describe here the paradigm of Z-type N2OR, whose characteristics have been studied in most detail in the genera Pseudomonas and Paracoccus. Sequenced bacterial genomes now provide an invaluable additional source of information. New strains harbouring nos genes and capability of N2O utilization are being uncovered. This reveals previously unknown relationships and allows pattern recognition and predictions. The core nos genes, nosZDFYL, share a common phylogeny. Most principal taxonomic lineages follow the same biochemical and genetic pattern and share the Z-type enzyme. A modified N2OR is found in Wolinella succinogenes, and circumstantial evidence also indicates for certain Archaea another type of N2OR. The current picture supports the view of evolution of N2O respiration prior to the separation of the domains Bacteria and Archaea. Lateral nos gene transfer from an epsilon-proteobacterium as donor is suggested for Magnetospirillum magnetotacticum and Dechloromonas aromatica. In a few cases, nos gene clusters are plasmid borne. Inorganic N2O metabolism is associated with a diversity of

Nitrite as a stimulus for ammonia-starved Nitrosomonas europaea

NARCIS (Netherlands)

Laanbroek, H.J.; Bär-Gilissen, M.J.; Hoogveld, H.L.

2002-01-01

Ammonia-starved cells of Nitrosomonas europaea are able to preserve a high level of ammonia-oxidizing activity in the absence of ammonium. However, when the nitrite-oxidizing cells that form part of the natural nitrifying community do not keep pace with the ammonia-oxidizing cells, nitrite

Population diversity of ammonium oxidizers investigated by specific PCR amplification

Science.gov (United States)

Ward, B.B.; Voytek, M.A.; Witzel, K.-P.

1997-01-01

The species composition of ammonia-oxidizing bacteria in aquatic environments was investigated using PCR primers for 16S rRNA genes to amplify specific subsets of the total ammonia-oxidizer population. The specificity of the amplification reactions was determined using total genomic DNA from known nitrifying strains and non-nitrifying strains identified as having similar rDNA sequences. Specificity of amplification was determined both for direct amplification, using the nitrifier specific primers, and with nested amplification, in which the nitrifier primers were used to reamplify a fragment obtained from direct amplification with Eubacterial universal primers. The present level of specificity allows the distinction between Nitrosomonas europaea, Nitrosomonas sp. (marine) and the other known ammonia-oxidizers in the beta subclass of the Proteobacteria. Using total DNA extracted from natural samples, we used direct amplification to determine presence/absence of different species groups. Species composition was found to differ among depths in vertical profiles of lake samples and among samples and enrichments from various other aquatic environments. Nested PCR yielded several more positive reactions, which implies that nitrifier DNA was present in most samples, but often at very low levels.

Development of the kinetic model of platinum catalyzed ammonia oxidation in a microreactor

NARCIS (Netherlands)

Rebrov, E.V.; Croon, de M.H.J.M.; Schouten, J.C.

2002-01-01

The ammonia oxidation reaction on supported polycrystalline platinum catalyst was investigated in an aluminum-based microreactor. An extensive set of reactions was included in the chemical reactor modeling to facilitate the construction of a kinetic model capable of satisfactory predictions for a

Site-Specific Reactivity of Copper Chabazite Zeolites with Nitric Oxide, Ammonia, and Oxygen

DEFF Research Database (Denmark)

Godiksen, Anita; Isaksen, Oliver L.; Rasmussen, Søren B.

2018-01-01

In-situ electron paramagnetic resonance (EPR) spectroscopy was applied to dilute copper chabazite (CHA) zeolites under gas flows relevant for the selective catalytic reduction of NO with ammonia (NH3-SCR). Under both reducing and oxidizing conditions, we observed differences in reactivity between...

Enhanced and selective ammonia sensing of reduced graphene oxide based chemo resistive sensor at room temperature

Science.gov (United States)

Kumar, Ramesh; Kaur, Amarjeet

2016-05-01

The reduced graphene oxide thin films were fabricated by using the spin coating method. The reduced graphene oxide samples were characterised by Raman studies to obtain corresponding D and G bands at 1360 and 1590 cm-1 respectively. Fourier transform infra-red (FTIR) spectra consists of peak corresponds to sp2 hybridisation of carbon atoms at 1560 cm-1. The reduced graphene oxide based chemoresistive sensor exhibited a p-type semiconductor behaviour in ambient conditions and showed good sensitivity to different concentration of ammonia from 25 ppm to 500 ppm and excellent selectivity at room temperature. The sensor displays selectivity to several hazardous vapours such as methanol, ethanol, acetone and hydrazine hydrate. The sensor demonstrated a sensitivity of 9.8 at 25 ppm concentration of ammonia with response time of 163 seconds.

Ammonia, nitrous oxide and hydrogen cyanide emissions from five passenger vehicles

International Nuclear Information System (INIS)

Karlsson, Hua Lu

2004-01-01

In this paper, three unregulated components, ammonia, nitrous oxide and hydrogen cyanide, emitted from five passenger vehicles are investigated. With focus upon emission factors from existing production technology, vehicles produced between 1989 and 1998 with considerable mileage (7000 to 280,000) are chosen. Among the five vehicles, four were sold in the European market, whereas one was sold in the US market. The vehicles are tested on a chassis dynamometer. An EU2000 Driving Cycle (NEDC) and a US Urban Driving Cycle (UDC) of the Federal Test Procedure 75 (FTP-75) are used in the study. The regulated emissions are measured using a Horiba Mexa series. Unregulated emissions, ammonia (NH 3 ), nitrous oxide (N 2 O) and hydrogen cyanide (HCN) are analysed by mass spectrometer, gas chromatography and CNT-NA, TIM315-74W method, respectively. Both the unregulated emissions and the regulated emissions show driving cycle dependency; and they are also improved with newer vehicle and emission control technology. However, a gasoline direct injection vehicle (relatively new technology in this study) has rather high regulated emissions, whereas the NH 3 , N 2 O and HCN emissions are low

Ammonia, nitrous oxide and hydrogen cyanide emissions from five passenger vehicles.

Science.gov (United States)

Karlsson, Hua Lu

2004-12-01

In this paper, three unregulated components, ammonia, nitrous oxide and hydrogen cyanide, emitted from five passenger vehicles are investigated. With focus upon emission factors from existing production technology, vehicles produced between 1989 and 1998 with considerable mileage (7000 to 280,000) are chosen. Among the five vehicles, four were sold in the European market, whereas one was sold in the US market. The vehicles are tested on a chassis dynamometer. An EU2000 Driving Cycle (NEDC) and a US Urban Driving Cycle (UDC) of the Federal Test Procedure 75 (FTP-75) are used in the study. The regulated emissions are measured using a Horiba Mexa series. Unregulated emissions, ammonia (NH(3)), nitrous oxide (N(2)O) and hydrogen cyanide (HCN) are analysed by mass spectrometer, gas chromatography and CNT-NA, TIM315-74W method, respectively. Both the unregulated emissions and the regulated emissions show driving cycle dependency; and they are also improved with newer vehicle and emission control technology. However, a gasoline direct injection vehicle (relatively new technology in this study) has rather high regulated emissions, whereas the NH(3), N(2)O and HCN emissions are low.

The role of adsorbates in the electrochemical oxidation of ammonia on noble and transition metal electrodes

NARCIS (Netherlands)

Vooys, de A.C.A.; Koper, M.T.M.; Santen, van R.A.; Veen, van J.A.R.

2001-01-01

The activity for ammonia oxidation and the intermediates formed during the reaction have been studied on platinum, palladium, rhodium, ruthenium, iridium, copper, silver and gold electrodes. The activity in the selective oxidation to N-2 is related directly to the nature of the species at the

Abundance and diversity of bacterial nitrifiers and denitrifiers and their functional genes in tannery wastewater treatment plants revealed by high-throughput sequencing.

Directory of Open Access Journals (Sweden)

Zhu Wang

Full Text Available Biological nitrification/denitrification is frequently used to remove nitrogen from tannery wastewater containing high concentrations of ammonia. However, information is limited about the bacterial nitrifiers and denitrifiers and their functional genes in tannery wastewater treatment plants (WWTPs due to the low-throughput of the previously used methods. In this study, 454 pyrosequencing and Illumina high-throughput sequencing, combined with molecular methods, were used to comprehensively characterize structures and functions of nitrification and denitrification bacterial communities in aerobic and anaerobic sludge of two full-scale tannery WWTPs. Pyrosequencing of 16S rRNA genes showed that Proteobacteria and Synergistetes dominated in the aerobic and anaerobic sludge, respectively. Ammonia-oxidizing bacteria (AOB amoA gene cloning revealed that Nitrosomonas europaea dominated the ammonia-oxidizing community in the WWTPs. Metagenomic analysis showed that the denitrifiers mainly included the genera of Thauera, Paracoccus, Hyphomicrobium, Comamonas and Azoarcus, which may greatly contribute to the nitrogen removal in the two WWTPs. It is interesting that AOB and ammonia-oxidizing archaea had low abundance although both WWTPs demonstrated high ammonium removal efficiency. Good correlation between the qPCR and metagenomic analysis is observed for the quantification of functional genes amoA, nirK, nirS and nosZ, indicating that the metagenomic approach may be a promising method used to comprehensively investigate the abundance of functional genes of nitrifiers and denitrifiers in the environment.

Enhanced and selective ammonia sensing of reduced graphene oxide based chemo resistive sensor at room temperature

Energy Technology Data Exchange (ETDEWEB)

Kumar, Ramesh, E-mail: rameshphysicsdu@gmail.com; Kaur, Amarjeet, E-mail: amarkaur@physics.du.ac.in [Department of Physics and Astrophysics, University of Delhi, Delhi-110007 (India)

2016-05-06

The reduced graphene oxide thin films were fabricated by using the spin coating method. The reduced graphene oxide samples were characterised by Raman studies to obtain corresponding D and G bands at 1360 and 1590 cm{sup −1} respectively. Fourier transform infra-red (FTIR) spectra consists of peak corresponds to sp{sup 2} hybridisation of carbon atoms at 1560 cm{sup −1}. The reduced graphene oxide based chemoresistive sensor exhibited a p-type semiconductor behaviour in ambient conditions and showed good sensitivity to different concentration of ammonia from 25 ppm to 500 ppm and excellent selectivity at room temperature. The sensor displays selectivity to several hazardous vapours such as methanol, ethanol, acetone and hydrazine hydrate. The sensor demonstrated a sensitivity of 9.8 at 25 ppm concentration of ammonia with response time of 163 seconds.

Shifts in the abundance and community structure of soil ammonia oxidizers in a wet sclerophyll forest under long-term prescribed burning.

Science.gov (United States)

Long, Xi-En; Chen, Chengrong; Xu, Zhihong; He, Ji-Zheng

2014-02-01

Fire shapes global biome distribution and promotes the terrestrial biogeochemical cycles. Ammonia-oxidizing bacteria (AOB) and archaea (AOA) play a vital role in the biogeochemical cycling of nitrogen (N). However, behaviors of AOB and AOA under long-term prescribed burning remain unclear. This study was to examine how fire affected the abundances and communities of soil AOB and AOA. A long-term repeated forest fire experiment with three burning treatments (never burnt, B0; biennially burnt, B2; and quadrennially burnt, B4) was used in this study. The abundances and community structure of soil AOB and AOA were determined using quantitative PCR, restriction fragment length polymorphism and clone library. More frequent fires (B2) increased the abundance of bacterium amoA gene, but tended to decrease archaeal amoA genes. Fire also modified the composition of AOA and AOB communities. Canonical correspondence analysis showed soil pH and dissolved organic C (DOC) strongly affected AOB genotypes, while nitrate-N and DOC shaped the AOA distribution. The increased abundance of bacterium amoA gene by fires may imply an important role of AOB in nitrification in fire-affected soils. The fire-induced shift in the community composition of AOB and AOA demonstrates that fire can disturb nutrient cycles. © 2013.

Microbial diversity: a bonanza of phyla.

Science.gov (United States)

Eme, Laura; Doolittle, W Ford

2015-03-16

Metagenomics and single-cell genomics are now the gold standard for exploring microbial diversity. A new study focusing on enigmatic ultra-small archaea greatly expands known genetic diversity within Archaea, and reports the first complete archaeal genomes reconstructed from metagenomic data only. Copyright © 2015 Elsevier Ltd. All rights reserved.

Biochar type and factors affecting N transformation, ammonia volatilization, and nitrous oxide emissions

Science.gov (United States)

Soil amendment with biochar has shown the potential to improve nitrogen (N) availability for plant uptake and reduce environmental losses via ammonia (NH3) and nitrous oxide (N2O) emissions. There are still many unknowns on how biochar type and soil conditions affect N dynamics and processes associa...

Empowering a mesophilic inoculum for thermophilic nitrification: Growth mode and temperature pattern as critical proliferation factors for archaeal ammonia oxidizers.

Science.gov (United States)

Courtens, Emilie N P; Vandekerckhove, Tom; Prat, Delphine; Vilchez-Vargas, Ramiro; Vital, Marius; Pieper, Dietmar H; Meerbergen, Ken; Lievens, Bart; Boon, Nico; Vlaeminck, Siegfried E

2016-04-01

Cost-efficient biological treatment of warm nitrogenous wastewaters requires the development of thermophilic nitrogen removal processes. Only one thermophilic nitrifying bioreactor was described so far, achieving 200 mg N L(-1) d(-1) after more than 300 days of enrichment from compost samples. From the practical point of view in which existing plants would be upgraded, however, a more time-efficient development strategy based on mesophilic nitrifying sludge is preferred. This study evaluated the adaptive capacities of mesophilic nitrifying sludge for two linear temperature increase patterns (non-oscillating vs. oscillating), two different slopes (0.25 vs. 0.08 °C d(-1)) and two different reactor types (floc vs. biofilm growth). The oscillating temperature pattern (0.25 °C d(-1)) and the moving bed biofilm reactor (0.08 °C d(-1)) could not reach nitrification at temperatures higher than 46 °C. However, nitrification rates up to 800 mg N L(-1) d(-1) and 150 mg N g(-1) volatile suspended solids d(-1) were achieved at a temperature as high as 49 °C by imposing the slowest linear temperature increase to floccular sludge. Microbial community analysis revealed that this successful transition was related with a shift in ammonium oxidizing archaea dominating ammonia oxidizing bacteria, while for nitrite oxidation Nitrospira spp. was constantly more abundant than Nitrobacter spp.. This observation was accompanied with an increase in observed sludge yield and a shift in maximal optimum temperature, determined with ex-situ temperature sensitivity measurements, predicting an upcoming reactor failure at higher temperature. Overall, this study achieved nitrification at 49 °C within 150 days by gradual adaptation of mesophilic sludge, and showed that ex-situ temperature sensitivity screening can be used to monitor and steer the transition process. Copyright © 2016 Elsevier Ltd. All rights reserved.

Quantitative analysis of ammonia-oxidizing bacteria in a combined system of MBR and worm reactors treating synthetic wastewater.

Science.gov (United States)

Liu, Jia; Tian, Yu; Wang, Dezhen; Lu, Yaobin; Zhang, Jun; Zuo, Wei

2014-12-01

The Static Sequencing Batch Worm Reactor (SSBWR) followed by the MBR (S-MBR) is one of the advanced excess sludge treatments. In this paper, the control MBR (C-MBR) and the SSBWR-MBR were operated in parallel to study the changes of NH3-N removal and ammonia oxidizing bacteria (AOB). The results showed that the capacity of NH3-N removal of the S-MBR was improved by the worm reactors along with the operation. The S-MBR was favorable because it selected for the higher activity of the ammonia oxidization and better cells appearance of the sludge. The five species (Nitrosomonas, Betaproteobacteria, Clostridium, Dechloromonas and Bacteria) were found to be significantly correlate with the ammonia oxidization functions and performance of NH3-N removal in the C-MBR and S-MBR. The Nitrosomonas, Betaproteobacteria and Dechloromonas remained and eventually enriched in the S-MBR played a primary role in the NH3-N removal of the S-MBR. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effects of reforestation on ammonia-oxidizing microbial community composition and abundance in subtropical acidic forest soils.

Science.gov (United States)

Wu, Ruo-Nan; Meng, Han; Wang, Yong-Feng; Gu, Ji-Dong

2018-06-01

Forest ecosystems have great ecological values in mitigation of climate change and protection of biodiversity of flora and fauna; re-forestry is commonly used to enhance the sequestration of atmospheric CO 2 into forest storage biomass. Therefore, seasonal and spatial dynamics of the major microbial players in nitrification, ammonia-oxidizing archaea (AOA) and bacteria (AOB), in acidic soils of young and matured revegetated forests were investigated to elucidate the changes of microbial communities during forest restoration, and compared to delineate the patterns of community shifts under the influences of environmental factors. AOA were more abundant than AOB in both young and matured revegetated forest soils in both summer and winter seasons. In summer, however, the abundance of amoA-AOA decreased remarkably (p < 0.01), ranging from 1.90 (± 0.07) × 10 8 copies per gram dry soil in matured forest to 5.04 (± 0.43) × 10 8 copies per gram dry soil in young forest, and amoA-AOB was below detection limits to obtain any meaningful values. Moreover, exchangeable Al 3+ and organic matter were found to regulate the physiologically functional nitrifiers, especially AOA abundance in acidic forest soils. AOB community in winter showed stronger correlation with the restoration status of revegetated forests and AOA community dominated by Nitrosotalea devanaterra, in contrast, was more sensitive to the seasonal and spatial variations of environmental factors. These results enrich the current knowledge of nitrification during re-forestry and provide valuable information to developmental status of revegetated forests for management through microbial analysis.

Public aquaria as long-term enrichments for investigating planktonic Archaea

Science.gov (United States)

Goldenstein, Nadine I.; Warren, Courtney E.; Lipp, Julius S.; Pagani, Mark; Hinrichs, Kai-Uwe

2016-04-01

The most abundant group of planktonic Archaea , the so-called Thaumarchaeota, represents 20% of all marine planktonic microorganisms (Karner et al., 2001) and their energy efficient performance of nitrification makes them key players in the global nitrogen- and carbon-cycle (Könneke et al., 2014). Furthermore, planktonic Archaea are considered to be the major producers of specific microbial membrane lipids that are extensively used as paleoproxies in marine climate research (Schouten et al., 2002). Therefore, assessing the parameters controlling the distribution of Archaea in the marine water column is crucial for studies of modern and past marine environments. Although diverse studies utilizing DNA- and biomarker-based approaches have constrained the turnover and distribution of marine Archaea, the environmental factors affecting their abundance and activity (e.g., Wuchter et al., 2006; Bale et al., 2013) are still poorly understood. Further, previous surveys, using enrichment cultivation and pure culture experiments, provided valuable information on adaptation of planktonic Archaea to changes of parameters affecting growth conditions, such as temperature, salinity and growth stage (Elling et al., 2014, 2015). Hence, we know that planktonic Archaea directly adapt their membranes to changing growth conditions, but also that environmental selection for individual phylogenetic groups of these organisms is also reflected in the membrane lipid pool. Extending these studies, this project further aims at constraining the environmental parameters controlling archaeal abundance in the marine environment. Public aquaria, which are comparable to perfectly monitored long-term enrichment cultures, are optimal sampling sites for this task. A comprehensive set of 120 water and substrate samples from fresh, marine and brackish systems exhibiting diverse conditions was selected from 15 public aquaria at the east and west coast of the USA. These samples were examined for their

Influence of tropical leaf litter on nitrogen mineralization and community structure of ammonia-oxidizing bacteria

Directory of Open Access Journals (Sweden)

Diallo, MD.

2015-01-01

Full Text Available Description of the subject. The present study concerns the relationships among leaf litter decomposition, substrate quality, ammonia-oxidizing bacteria (AOB community composition and nitrogen (N availability. Decomposition of organic matter affects the biogeochemical cycling of carbon (C and N. Since the composition of the soil microbial community can alter the physiological capacity of the community, it is timely to study the litter quality effect on N dynamic in ecosystems. Objectives. The aim of this study was to determine the influence of leaf litter decomposition on N mineralization. The specific objectives of this study were to evaluate the influence of the litter biochemistry of five plants species (Faidherbia albida A.Chev., Azadirachta indica A.Juss., Casuarina equisetifolia L., Andropogon gayanus Kunth and Eragrostis tremula Hochst. ex Steud. on N mineralization in a tropical ferrous soil (Lixisol, nitrification, and genetic diversity of ammonia-oxidizing bacteria. Denaturing gradient gel electrophoresis (DGGE of amplified fragments of genes coding for 16S rRNA was used to study the development of bacterial communities during decomposition of leaf litter in soils. Method. Community structure of AOB was determined at two time periods: day 0 and day 140. Ten strains were tested and each of these strains produced a single band. Thus, DGGE DNA band patterns were used to estimate bacterial diversity. Plant secondary compounds such as polyphenols are purported to influence nutrient cycling by affecting organic matter degradation, mineralization rates, N availability and humus formation. In a laboratory study, we investigated the influence of six phenolic acids (ferulic, gallic, vanillic, syringic, p-coumaric and p-HBA acids commonly found in the plant residues on N mineralization and NH4+ and NO3- production in soils. Results. The results showed that litter type did affect soil nitrification. Faidherbia albida litter was associated with

Do freshwater macrophytes influence the community structure of ammonia-oxidizing and denitrifying bacteria in the rhizospere?

DEFF Research Database (Denmark)

Herrmann, Martina; Schramm, Andreas

2006-01-01

to unvegetated sediment, especially with respect to the availability of oxygen, organic carbon, and inorganic nitrogen. We hypothesize that macrophyte species create specific niches for ammonia oxidizing and nitrate-reducing bacteria in their rhizosphere, leading to plant-dependant differences in abundance...... dortmanna have been shown to release oxygen from their roots and to stimulate nitrification and coupled nitrification-denitrification in the rhizosphere. Together with the excretion of root exudates, this effect leads to strongly modified microenvironments at the root surface and in the rhizosphere compared......-denitrification using the 15N isotope pairing technique. Ammonia-oxidizing and nitrate-reducing populations are analyzed based on the ammonia monooxygenase gene (amoA) and the nitrate reductase gene (narG) as functional markers. Preliminary data indicate that there in fact exist differences in the community composition...

[A novel archaeal phylum: thaumarchaeota--a review].

Science.gov (United States)

Zhang, Limei; He, Jizheng

2012-04-04

Based on the archaeal 16S rRNA gene phylogenetic tree, the archaeal domain is divided into two major phyla, Euryarchaeota and Crenarchaeota. During the past 20 years, diverse groups of archaea have been found to be widely distributed in moderate environments with the rapid development and application of molecular techniques in microbial ecology. Increasing evidence demonstrated that these archaea, especially ammonia-oxidizing archaea, play a major role in biogeochemical cycles of nitrogen and carbon elements. These mesophilic archaea were placed initially as a sister group of the Crenarchaeota and named as "non-thermophilic Crenarchaeota". More recently, phylogenetic analyses based on more SSU and SLU rDNA sequences suggested that the non-thermophilic Crenarchaeota constituted a separate phylum of the Archaea that branched off before the separation of Crenarchaeota and Euryarchaeota. The Thaumarchaeota (the Greek "Thaumas", meaning wonder) was therefore proposed for a novel phylum, as the third archaeal phylum. More studies based on r-proteins and comparative genomics confirm that the Thaumarchaeota are distinct from Crenarchaeota. In this paper, we gave a translated Chinese name for Thaumarchaeota and reviewed the recent progress on the phylogeny position, genetics, ecology and physiology of the Thaumarchaeota.

Ammonia chemistry in a flameless jet

Energy Technology Data Exchange (ETDEWEB)

Zieba, Mariusz; Schuster, Anja; Scheffknecht, Guenter [Institute of Process Engineering and Power Plant Technology, University of Stuttgart, Pfaffenwaldring 23, D-70569 Stuttgart (Germany); Brink, Anders; Hupa, Mikko [Process Chemistry Centre, Aabo Akademi University, Biskopsgatan 8, 20500 Aabo (Finland)

2009-10-15

In this paper, the nitrogen chemistry in an ammonia (NH{sub 3}) doped flameless jet is investigated using a kinetic reactor network model. The reactor network model is used to explain the main differences in ammonia chemistry for methane (CH{sub 4})-containing fuels and methane-free fuels. The chemical pathways of nitrogen oxides (NO{sub x}) formation and destruction are identified using rate-of-production analysis. The results show that in the case of natural gas, ammonia reacts relatively late at fuel lean condition leading to high NO{sub x} emissions. In the pre-ignition zone, the ammonia chemistry is blocked due to the absence of free radicals which are consumed by methane-methyl radical (CH{sub 3}) conversion. In the case of methane-free gas, the ammonia reacted very rapidly and complete decomposition was reached in the fuel rich region of the jet. In this case the necessary radicals for the ammonia conversion are generated from hydrogen (H{sub 2}) oxidation. (author)

Spatial distribution of archaeal and bacterial ammonia oxidizers in the littoral buffer zone of a nitrogen-rich lake.

Science.gov (United States)

Wang, Yu; Zhu, Guibing; Ye, Lei; Feng, Xiaojuan; Op den Camp, Huub J M; Yin, Chengqing

2012-01-01

The spatial distribution and diversity of archaeal and bacterial ammonia oxidizers (AOA and AOB) were evaluated targeting amoA genes in the gradient of a littoral buffer zone which has been identified as a hot spot for N cycling. Here we found high spatial heterogeneity in the nitrification rate and abundance of ammonia oxidizers in the five sampling sites. The bacterial amoA gene was numerically dominant in most of the surface soil but decreased dramatically in deep layers. Higher nitrification potentials were detected in two sites near the land/water interface at 4.4-6.1 microg NO(2-)-N/(g dry weight soil x hr), while only 1.0-1.7 microg NO(2-)-N/(g dry weight soil x hr) was measured at other sites. The potential nitrification rates were proportional to the amoA gene abundance for AOB, but with no significant correlation with AOA. The NH4+ concentration was the most determinative parameter for the abundance of AOB and potential nitrification rates in this study. Higher richness in the surface layer was found in the analysis of biodiversity. Phylogenetic analysis revealed that most of the bacterial amoA sequences in surface soil were affiliated with the genus of Nitrosopira while the archaeal sequences were almost equally affiliated with Candidatus 'Nitrososphaera gargensis' and Candidatus 'Nitrosocaldus yellowstonii'. The spatial distribution of AOA and AOB indicated that bacteria may play a more important role in nitrification in the littoral buffer zone of a N-rich lake.

Energy-mediated versus ammonium-regulated gene expression in the obligate ammonia-oxidizing bacterium, Nitrosococcus oceani

Directory of Open Access Journals (Sweden)

Lisa Y Stein

2013-09-01

Full Text Available Ammonia serves as the source of energy and reductant and as a signaling molecule that regulates gene expression in obligate ammonia-oxidizing chemolithotrophic microorganisms. The gammaproteobacterium, Nitrosococcus oceani, was the first obligate ammonia-oxidizer isolated from seawater and is one of the model systems for ammonia chemolithotrophy. We compared global transcriptional responses to ammonium and the catabolic intermediate, hydroxylamine, in ammonium-starved and non-starved cultures of N. oceani to discriminate transcriptional effects of ammonium from a change in overall energy and redox status upon catabolite availability. The most highly expressed genes from ammonium- or hydroxylamine-treated relative to starved cells are implicated in catabolic electron flow, carbon fixation, nitrogen assimilation, ribosome structure and stress tolerance. Catabolic inventory-encoding genes, including electron flow-terminating Complexes IV, FoF1 ATPase, transporters, and transcriptional regulators were among the most highly expressed genes in cells exposed only to ammonium relative to starved cells, although the differences compared to steady-state transcript levels were less pronounced. Reduction in steady-state mRNA levels from hydroxylamine-treated relative to starved-cells were less than five-fold. In contrast, several transcripts from ammonium-treated relative to starved cells were significantly less abundant including those for forward Complex I and a gene cluster of cytochrome c encoding proteins. Identified uneven steady-state transcript levels of co-expressed clustered genes support previously reported differential regulation at the levels of transcription and transcript stability. Our results differentiated between rapid regulation of core genes upon a change in cellular redox status versus those responsive to ammonium as a signaling molecule in N. oceani, both confirming and extending our knowledge of metabolic modules involved in ammonia

A virus of hyperthermophilic archaea with a unique architecture among DNA viruses

NARCIS (Netherlands)

Rensen, Elena Ilka; Mochizuki, Tomohiro; Quemin, Emmanuelle; Schouten, S.; Krupovic, Mart; Prangishvili, David

2016-01-01

Viruses package their genetic material in diverse ways. Most known strategies include encapsulation of nucleic acids into spherical or filamentous virions with icosahedral or helical symmetry, respectively. Filamentous viruses with dsDNA genomes are currently associated exclusively with Archaea.

Microstructure and electrical-optical properties of cesium tungsten oxides synthesized by solvothermal reaction followed by ammonia annealing

International Nuclear Information System (INIS)

Liu Jingxiao; Ando, Yoshihiko; Dong Xiaoli; Shi Fei; Yin Shu; Adachi, Kenji; Chonan, Takeshi; Tanaka, Akikazu; Sato, Tsugio

2010-01-01

Cesium tungsten oxides (Cs x WO 3 ) were synthesized by solvothermal reactions using ethanol and 57.1 vol% ethanol aqueous solution at 200 o C for 12 h, and the effects of post annealing in ammonia atmosphere on the microstructure and electrical-optical properties were investigated. Agglomerated particles consisting of disk-like nanoparticles and nanorods of Cs x WO 3 were formed in the pure ethanol and ethanol aqueous solutions, respectively. The samples retained the original morphology and crystallinity after annealing in ammonia atmosphere up to 500 o C, while a small amount of nitrogen ion were incorporated in the lattice. The as-prepared Cs x WO 3 sample showed excellent near infrared (NIR) light shielding ability as well as high transparency in the visible light region. The electrical resistivity of the pressed pellets of the powders prepared in pure ethanol and 57.1 vol% ethanol aqueous solution greatly decreased after ammonia annealing at 500 o C, i.e., from 734 to 31.5 and 231 to 3.58 Ω cm, respectively. - Graphical abstract: Cesium tungsten oxides (Cs x WO 3 ) with different morphology were synthesized by solvothermal reaction, and the effects of post-ammonia annealing on the microstructure and electrical-optical properties were investigated.

A Ferredoxin- and F420H2-Dependent, Electron-Bifurcating, Heterodisulfide Reductase with Homologs in the Domains Bacteria and Archaea

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Zhen Yan

2017-02-01

Full Text Available Heterodisulfide reductases (Hdr of the HdrABC class are ancient enzymes and a component of the anaerobic core belonging to the prokaryotic common ancestor. The ancient origin is consistent with the widespread occurrence of genes encoding putative HdrABC homologs in metabolically diverse prokaryotes predicting diverse physiological functions; however, only one HdrABC has been characterized and that was from a narrow metabolic group of obligate CO2-reducing methanogenic anaerobes (methanogens from the domain Archaea. Here we report the biochemical characterization of an HdrABC homolog (HdrA2B2C2 from the acetate-utilizing methanogen Methanosarcina acetivorans with unusual properties structurally and functionally distinct from the only other HdrABC characterized. Homologs of the HdrA2B2C2 archetype are present in phylogenetically and metabolically diverse species from the domains Bacteria and Archaea. The expression of the individual HdrA2, HdrB2, and HdrB2C2 enzymes in Escherichia coli, and reconstitution of an active HdrA2B2C2 complex, revealed an intersubunit electron transport pathway dependent on ferredoxin or coenzyme F420 (F420H2 as an electron donor. Remarkably, HdrA2B2C2 couples the previously unknown endergonic oxidation of F420H2 and reduction of ferredoxin with the exergonic oxidation of F420H2 and reduction of the heterodisulfide of coenzyme M and coenzyme B (CoMS-SCoB. The unique electron bifurcation predicts a role for HdrA2B2C2 in Fe(III-dependent anaerobic methane oxidation (ANME by M. acetivorans and uncultured species from ANME environments. HdrA2B2C2, ubiquitous in acetotrophic methanogens, was shown to participate in electron transfer during acetotrophic growth of M. acetivorans and proposed to be essential for growth in the environment when acetate is limiting.

Subgroup characteristics of marine methane-oxidizing ANME-2 archaea and their syntrophic partners revealed by integrated multimodal analytical microscopy.

Science.gov (United States)

McGlynn, Shawn E; Chadwick, Grayson L; O'Neill, Ariel; Mackey, Mason; Thor, Andrea; Deerinck, Thomas J; Ellisman, Mark H; Orphan, Victoria J

2018-04-06

Phylogenetically diverse environmental ANME archaea and sulfate-reducing bacteria cooperatively catalyze the anaerobic oxidation of methane oxidation (AOM) in multi-celled consortia within methane seep environments. To better understand these cells and their symbiotic associations, we applied a suite of electron microscopy approaches including correlative f luorescence i n s itu h ybridization - e lectron m icroscopy (FISH-EM), t ransmission e lectron m icroscopy (TEM), and s erial b lock face scanning e lectron m icroscopy 3D reconstructions (SBEM). FISH-EM of methane seep derived consortia revealed phylogenetic variability in terms of cell morphology, ultrastructure, and storage granules. Representatives of the ANME-2b clade, but not other ANME-2 groups, contained polyphosphate-like granules, while some bacteria associated with ANME-2a/2c contained two distinct phases of iron mineral chains resembling magnetosomes. 3D segmentation of two ANME-2 consortia types revealed cellular volumes of ANME and their symbiotic partners which were larger than previous estimates based on light microscopy. Phosphorous granule containing ANME (tentatively ANME-2b) were larger than both ANME with no granules and partner bacteria. This cell type was observed with up to 4 granules per cell and the volume of the cell was larger in proportion to the number of granules inside it, but the percent of the cell occupied by these granules did not vary with granule number. These results illuminate distinctions between ANME-2 archaeal lineages and partnering bacterial populations that are apparently unified in their capability of performing anaerobic methane oxidation. Importance Methane oxidation in anaerobic environments can be accomplished by a number of archaeal groups, some of which live in syntrophic relationships with bacteria in structured consortia. Little is known as to the distinguishing characteristics of these groups. Here we applied imaging approaches to better understand the

Archaea in metazoan diets: implications for food webs and biogeochemical cycling.

Science.gov (United States)

Thurber, Andrew R; Levin, Lisa A; Orphan, Victoria J; Marlow, Jeffrey J

2012-08-01

Although the importance of trophic linkages, including 'top-down forcing', on energy flow and ecosystem productivity is recognized, the influence of metazoan grazing on Archaea and the biogeochemical processes that they mediate is unknown. Here, we test if: (1) Archaea provide a food source sufficient to allow metazoan fauna to complete their life cycle; (2) neutral lipid biomarkers (including crocetane) can be used to identify Archaea consumers; and (3) archaeal aggregates are a dietary source for methane seep metazoans. In the laboratory, we demonstrated that a dorvilleid polychaete, Ophryotrocha labronica, can complete its life cycle on two strains of Euryarchaeota with the same growth rate as when fed bacterial and eukaryotic food. Archaea were therefore confirmed as a digestible and nutritious food source sufficient to sustain metazoan populations. Both strains of Euryarchaeota used as food sources had unique lipids that were not incorporated into O. labronica tissues. At methane seeps, sulfate-reducing bacteria that form aggregations and live syntrophically with anaerobic-methane oxidizing Archaea contain isotopically and structurally unique fatty acids (FAs). These biomarkers were incorporated into tissues of an endolithofaunal dorvilleid polychaete species from Costa Rica (mean bulk δ(13)C=-92±4‰; polar lipids -116‰) documenting consumption of archaeal-bacterial aggregates. FA composition of additional soft-sediment methane seep species from Oregon and California provided evidence that consumption of archaeal-bacterial aggregates is widespread at methane seeps. This work is the first to show that Archaea are consumed by heterotrophic metazoans, a trophic process we coin as 'archivory'.

Trait-based representation of biological nitrification: Model development, testing, and predicted community composition

Directory of Open Access Journals (Sweden)

Nick eBouskill

2012-10-01

Full Text Available Trait-based microbial models show clear promise as tools to represent the diversity and activity of microorganisms across ecosystem gradients. These models parameterize specific traits that determine the relative fitness of an ‘organism’ in a given environment, and represent the complexity of biological systems across temporal and spatial scales. In this study we introduce a microbial community trait-based modeling framework (MicroTrait focused on nitrification (MicroTrait-N that represents the ammonia-oxidizing bacteria (AOB and ammonia-oxidizing archaea (AOA and nitrite oxidizing bacteria (NOB using traits related to enzyme kinetics and physiological properties. We used this model to predict nitrifier diversity, ammonia (NH3 oxidation rates and nitrous oxide (N2O production across pH, temperature and substrate gradients. Predicted nitrifier diversity was predominantly determined by temperature and substrate availability, the latter was strongly influenced by pH. The model predicted that transient N2O production rates are maximized by a decoupling of the AOB and NOB communities, resulting in an accumulation and detoxification of nitrite to N2O by AOB. However, cumulative N2O production (over six month simulations is maximized in a system where the relationship between AOB and NOB is maintained. When the reactions uncouple, the AOB become unstable and biomass declines rapidly, resulting in decreased NH3 oxidation and N2O production. We evaluated this model against site level chemical datasets from the interior of Alaska and accurately simulated NH3 oxidation rates and the relative ratio of AOA:AOB biomass. The predicted community structure and activity indicate (a parameterization of a small number of traits may be sufficient to broadly characterize nitrifying community structure and (b changing decadal trends in climate and edaphic conditions could impact nitrification rates in ways that are not captured by extant biogeochemical models.

Method for forming ammonia

Science.gov (United States)

Kong, Peter C.; Pink, Robert J.; Zuck, Larry D.

2008-08-19

A method for forming ammonia is disclosed and which includes the steps of forming a plasma; providing a source of metal particles, and supplying the metal particles to the plasma to form metal nitride particles; and providing a substance, and reacting the metal nitride particles with the substance to produce ammonia, and an oxide byproduct.

DNA Repair and Photoprotection: Mechanisms of Overcoming Environmental Ultraviolet Radiation Exposure in Halophilic Archaea.

Science.gov (United States)

Jones, Daniel L; Baxter, Bonnie K

2017-01-01

Halophilic archaea push the limits of life at several extremes. In particular, they are noted for their biochemical strategies in dealing with osmotic stress, low water activity and cycles of desiccation in their hypersaline environments. Another feature common to their habitats is intense ultraviolet (UV) radiation, which is a challenge that microorganisms must overcome. The consequences of high UV exposure include DNA lesions arising directly from bond rearrangement of adjacent bipyrimidines, or indirectly from oxidative damage, which may ultimately result in mutation and cell death. As such, these microorganisms have evolved a number of strategies to navigate the threat of DNA damage, which we differentiate into two categories: DNA repair and photoprotection. Photoprotection encompasses damage avoidance strategies that serve as a "first line of defense," and in halophilic archaea include pigmentation by carotenoids, mechanisms of oxidative damage avoidance, polyploidy, and genomic signatures that make DNA less susceptible to photodamage. Photolesions that do arise are addressed by a number of DNA repair mechanisms that halophilic archaea efficiently utilize, which include photoreactivation, nucleotide excision repair, base excision repair, and homologous recombination. This review seeks to place DNA damage, repair, and photoprotection in the context of halophilic archaea and the solar radiation of their hypersaline environments. We also provide new insight into the breadth of strategies and how they may work together to produce remarkable UV-resistance for these microorganisms.

[Effects of transgenic Bt + CpTI cotton on rhizosphere bacteria and ammonia oxidizing bacteria population].

Science.gov (United States)

Dong, Lianhua; Meng, Ying; Wang, Jing

2014-03-04

The effect of transgenic cotton on the rhizosphere bacteria can be important to the risk assessment for the genetically modified crops. We studied the rhizosphere microbial community with cultivating genetically modified cotton. The effects of transgenic Bt + CpTI Cotton (SGK321) and its receptor cotton (SY321) on rhizosphere total bacteria and ammonia oxidizing bacteria population size were studied by using droplet digital PCR. We collected rhizosphere soil before cotton planting and along with the cotton growth stage (squaring stage, flowering stage, belling stage and boll opening stage). There was no significant change on the total bacterial population between the transgenic cotton and the receptor cotton along with the growth stage. However, the abundance of ammonia oxidizing bacteria (AOB) in both type of cottons showed significant difference between different growth stages, and the variation tendency was different. In squaring stage, the numbers of AOB in rhizosphere of SY321 and SGK321 increased 4 and 2 times, respectively. In flowering stage, AOB number in rhizosphere of SY321 significantly decreased to be 5.96 x 10(5) copies/g dry soil, however, that of SGK321 increased to be 1.25 x 10(6) copies/g dry soil. In belling stage, AOB number of SY321 greatly increased to be 1.49 x 10(6) copies/g dry soil, but no significant change was observed for AOB number of SGK321. In boll opening stage, both AOB number of SY321 and SGK321 clearly decreased and they were significantly different from each other. Compared to the non-genetically modified cotton, the change in abundance of ammonia oxidizing bacteria was slightly smooth in the transgenic cotton. Not only the cotton growth stage but also the cotton type caused this difference. The transgenic cotton can slow down the speed of ammonia transformation through impacting the number of AOB, which is advantageous for plant growth.

Taxonomic study of extreme halophilic archaea isolated from the "Salar de Atacama", Chile.

Science.gov (United States)

Lizama, C; Monteoliva-Sánchez, M; Prado, B; Ramos-Cormenzana, A; Weckesser, J; Campos, V

2001-11-01

A large number of halophilic bacteria were isolated in 1984-1992 from the Atacama Saltern (North of Chile). For this study 82 strains of extreme halophilic archaea were selected. The characterization was performed by using the phenotypic characters including morphological, physiological, biochemical, nutritional and antimicrobial susceptibility test. The results, together with those from reference strains, were subjected to numerical analysis, using the Simple Matching (S(SM)) coefficient and clustered by the unweighted pair group method of association (UPGMA). Fifteen phena were obtained at an 70% similarity level. The results obtained reveal a high diversity among the halophilic archaea isolated. Representative strains from the phena were chosen to determine their DNA base composition and the percentage of DNA-DNA similarity compared to reference strains. The 16S rRNA studies showed that some of these strains constitutes a new taxa of extreme halophilic archaea.

Massive Expansion of Marine Archaea During The Early Albian Oceanic Anoxic Event 1B

Science.gov (United States)

Kuypers, M. M.; Kuypers, M. M.; Blokker, P.; Erbacher, J.; Kinkel, H.; Pancost, R. D.; Pancost, R. D.; Schouten, S.; Sinninghe Damsté, J. S.

2001-12-01

Oceanic anoxic events (OAEs), periods of globally enhanced burial of organic matter (OM) in the marine realm, played an important role in the mid-Cretaceous `greenhouse climate' by effectively reducing atmospheric carbon dioxide concentrations. It is generally believed that these OAEs were caused either by decreased remineralisation or increased production of phytoplanktonic OM. Here we show that enhanced organic carbon (OC) burial during the early Albian OAE1b (~112 My) was caused by a different process. Combined biogeochemical and stable carbon isotopic analyses indicate that black shales from this period contain up to 80% of OC derived from archaea. Archaea-derived isoprenoidal tetraether membrane lipids and free and macromolecularly bound isoprenoid alkanes are abundantly present in these black shales. More specifically the presence of certain ether lipids (cyclic biphytane tetraethers) indicates representatives of the pelagic archaea. To the best of our knowledge this is the earliest fossil evidence for marine planktonic archaea, extending their geological record by more than 60 million years. The diversity of archaeal lipids recovered from the OAE1b black shales suggests that they derive from a multitude of archaeal species. However, the specific 13C enrichment of all such lipids indicates a common `heavy' (13C-rich) carbon source for the archaea and/or a common pathway of carbon-fixation with a reduced 13C fractionation effect compared to the Calvin cycle used by algae, cyanobacteria and higher plants. The large differences (up to 12%) in 13C/12C ratios between the algal biomarkers and the much more abundant archaeal molecular fossils suggest that the latter were not living heterotrophically on photoautotrophic biomass. It seems likely that the archaea present during OAE1b used a chemical energy source (possibly ammonium) for carbon fixation since photoautotrophy within the domain of the Archaea is restricted to only a few species from hypersaline

DNA Repair and Photoprotection: Mechanisms of Overcoming Environmental Ultraviolet Radiation Exposure in Halophilic Archaea

Directory of Open Access Journals (Sweden)

Daniel L. Jones

2017-09-01

Full Text Available Halophilic archaea push the limits of life at several extremes. In particular, they are noted for their biochemical strategies in dealing with osmotic stress, low water activity and cycles of desiccation in their hypersaline environments. Another feature common to their habitats is intense ultraviolet (UV radiation, which is a challenge that microorganisms must overcome. The consequences of high UV exposure include DNA lesions arising directly from bond rearrangement of adjacent bipyrimidines, or indirectly from oxidative damage, which may ultimately result in mutation and cell death. As such, these microorganisms have evolved a number of strategies to navigate the threat of DNA damage, which we differentiate into two categories: DNA repair and photoprotection. Photoprotection encompasses damage avoidance strategies that serve as a “first line of defense,” and in halophilic archaea include pigmentation by carotenoids, mechanisms of oxidative damage avoidance, polyploidy, and genomic signatures that make DNA less susceptible to photodamage. Photolesions that do arise are addressed by a number of DNA repair mechanisms that halophilic archaea efficiently utilize, which include photoreactivation, nucleotide excision repair, base excision repair, and homologous recombination. This review seeks to place DNA damage, repair, and photoprotection in the context of halophilic archaea and the solar radiation of their hypersaline environments. We also provide new insight into the breadth of strategies and how they may work together to produce remarkable UV-resistance for these microorganisms.

Ecology and Distribution of Thaumarchaea in the Deep Hypolimnion of Lake Maggiore

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Manuela Coci

2015-01-01

Full Text Available Ammonia-oxidizing Archaea (AOA play an important role in the oxidation of ammonia in terrestrial, marine, and geothermal habitats, as confirmed by a number of studies specifically focused on those environments. Much less is known about the ecological role of AOA in freshwaters. In order to reach a high resolution at the Thaumarchaea community level, the probe MGI-535 was specifically designed for this study and applied to fluorescence in situ hybridization and catalyzed reporter deposition (CARD-FISH analysis. We then applied it to a fine analysis of diversity and relative abundance of AOA in the deepest layers of the oligotrophic Lake Maggiore, confirming previous published results of AOA presence, but showing differences in abundance and distribution within the water column without significant seasonal trends with respect to Bacteria. Furthermore, phylogenetic analysis of AOA clone libraries from deep lake water and from a lake tributary, River Maggia, suggested the riverine origin of AOA of the deep hypolimnion of the lake.

Electron acceptors for anaerobic oxidation of methane drive microbial community structure and diversity in mud volcanoes.

Science.gov (United States)

Ren, Ge; Ma, Anzhou; Zhang, Yanfen; Deng, Ye; Zheng, Guodong; Zhuang, Xuliang; Zhuang, Guoqiang; Fortin, Danielle

2018-04-06

Mud volcanoes (MVs) emit globally significant quantities of methane into the atmosphere, however, methane cycling in such environments is not yet fully understood, as the roles of microbes and their associated biogeochemical processes have been largely overlooked. Here, we used data from high-throughput sequencing of microbial 16S rRNA gene amplicons from six MVs in the Junggar Basin in northwest China to quantify patterns of diversity and characterize the community structure of archaea and bacteria. We found anaerobic methanotrophs and diverse sulfate- and iron-reducing microbes in all of the samples, and the diversity of both archaeal and bacterial communities was strongly linked to the concentrations of sulfate, iron and nitrate, which could act as electron acceptors in anaerobic oxidation of methane (AOM). The impacts of sulfate/iron/nitrate on AOM in the MVs were verified by microcosm experiments. Further, two representative MVs were selected to explore the microbial interactions based on phylogenetic molecular ecological networks. The sites showed distinct network structures, key species and microbial interactions, with more complex and numerous linkages between methane-cycling microbes and their partners being observed in the iron/sulfate-rich MV. These findings suggest that electron acceptors are important factors driving the structure of microbial communities in these methane-rich environments. © 2018 The Authors. Environmental Microbiology published by Society for Applied Microbiology and John Wiley & Sons Ltd.

Stratification of archaeal membrane lipids in the ocean and implications for adaptation and chemotaxonomy of planktonic archaea.

Science.gov (United States)

Zhu, Chun; Wakeham, Stuart G; Elling, Felix J; Basse, Andreas; Mollenhauer, Gesine; Versteegh, Gerard J M; Könneke, Martin; Hinrichs, Kai-Uwe

2016-12-01

Membrane lipids of marine planktonic archaea have provided unique insights into archaeal ecology and paleoceanography. However, past studies of archaeal lipids in suspended particulate matter (SPM) and sediments mainly focused on a small class of fully saturated glycerol dibiphytanyl glycerol tetraether (GDGT) homologues identified decades ago. The apparent low structural diversity of GDGTs is in strong contrast to the high diversity of metabolism and taxonomy among planktonic archaea. Furthermore, adaptation of archaeal lipids in the deep ocean remains poorly constrained. We report the archaeal lipidome in SPM from diverse oceanic regimes. We extend the known inventory of planktonic archaeal lipids to include numerous unsaturated archaeal ether lipids (uns-AELs). We further reveal (i) different thermal regulations and polar headgroup compositions of membrane lipids between the epipelagic (≤ 100 m) and deep (>100 m) populations of archaea, (ii) stratification of unsaturated GDGTs with varying redox conditions, and (iii) enrichment of tetra-unsaturated archaeol and fully saturated GDGTs in epipelagic and deep oxygenated waters, respectively. Such stratified lipid patterns are consistent with the typical distribution of archaeal phylotypes in marine environments. We, thus, provide an ecological context for GDGT-based paleoclimatology and bring about the potential use of uns-AELs as biomarkers for planktonic Euryarchaeota. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

Emissions of ammonia, nitrous oxide and methane during composting of organic household waste

International Nuclear Information System (INIS)

Gunnarsdotter Beck-Friis, Barbro

2001-01-01

In Sweden, composting of source-separated organic household waste is increasing, both domestically at the small-scale, and in larger municipal plants. Composting means a microbial decomposition of organic material, which results in the production of environmentally undesirable gases, such as ammonia (NH 3 ), nitrous oxide (N 2 O) and methane (CH 4 ). The aim of this thesis was to study the emissions of NH 3 , N 2 O and CH 4 to the atmosphere during composting of source-separated organic household waste. The studies were conducted in an experimental reactor under constant and controlled conditions and in municipal compost heaps. Emissions of NH 3 , N 2 O and CH 4 occurred at different phases during composting. Ammonia started to volatilise during the shift from mesophilic to thermophilic conditions when short-chained fatty acids were decomposed. Nitrous oxide was only emitted during the first days of composting and later during the cooling phase when nitrate was formed. Methane was only produced during the thermophilic phase. Large municipal compost heaps are a significant source for the production and emission of the greenhouse gases N 2 O and CH 4 . To avoid unwanted gaseous emissions to the atmosphere during composting, gaseous exchange with the atmosphere should be controlled in future composting plants

A gold electrode modified with silver oxide nanoparticle decorated carbon nanotubes for electrochemical sensing of dissolved ammonia

International Nuclear Information System (INIS)

Rahman, Mohammed M.; Asiri, Abdullah M.; Balkhoyor, Hasan B.; Marwani, Hadi M.

2016-01-01

We have prepared silver oxide nanoparticles with a diameter of ∼ 15 nm and decorated with carbon nanotube nanocomposites (Ag_2O/CNT NCs) by a facile wet chemical method using reducing agents in alkaline medium. These NCs were characterized by UV/vis, FTIR and energy dispersive X-ray spectroscopy, by X-ray powder diffraction and field emission scanning electron microscopy. The NCs were then deposited on a flat gold electrode with the help of a conducting binder to result in an electrochemical sensor for aqueous ammonia using the I-V technique. Response is based on surface oxidation of ammonium hydroxide with electrode-adsorbed oxygen to form nitrogen oxide, these simultaneously liberating free electrons in the conduction band. Sensor features include a sensitivity of 32.856 μA.μM"-"1.cm"-"2, a low detection limit (1.3 pM at a signal to noise ratio of 3), reliability, reproducibility, ease of integration, and long term stability. The response to dissolved ammonia is linear (r"2: 0.9778) over the 0.01 nM to 0.1 mM concentration range. (author)

Ammonia synthesis by means of plasma over MgO catalyst

International Nuclear Information System (INIS)

Sugiyama, K.; Akazawa, K.; Matsuda, T.; Miura, H.; Oshima, M.

1986-01-01

Ammonia synthesis from H 2 -N 2 mixed gas was studied at room temperature in a glow-discharge plasma in the presence of metals or metal oxides. Magnesia (Mg0) and calcia (CaO), which are oxides with solid basicity, revealed catalytic activity in the plasma synthesis of ammonia, although they are catalytically inactive in industrial ammonia synthesis. The acid oxides (Al 2 0 3 W0 3 , and Si0 2 -Al 2 0 3 ) lead to the consumption of the reactant, i.e., the H2-N2 mixed gas. No ammonia was isolated. Metal catalysts showed higher activity than the above basic oxides. They have, however, different activities. The reaction was faster over the active materials than over sodium chloride (NaCl) or glass wool or in a blank reactor without any catalyst

Ammonia oxidizer populations vary with nitrogen cycling across a tropical montane mean annual temperature gradient

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S. Pierre; I. Hewson; J. P. Sparks; C. M. Litton; C. Giardina; P. M. Groffman; T. J. Fahey

2017-01-01

Functional gene approaches have been used to better understand the roles of microbes in driving forest soil nitrogen (N) cycling rates and bioavailability. Ammonia oxidation is a rate limiting step in nitrification, and is a key area for understanding environmental constraints on N availability in forests. We studied how increasing temperature affects the role of...

COMPARISON OF CATALYTIC ACTIVITIES BOTH FOR SELECTIVE OXIDATION AND DECOMPOSITION OF AMMONIA OVER Fe/HZβ CATALYST

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YELİZ ÇETİN

2016-11-01

Full Text Available Ammonia is one of the syngas contaminants that must be removed before using the syngas downstream applications. The most promising hot-gas clean-up techniques of ammonia are selective catalytic oxidation (SCO and catalytic decomposition. In this study, the catalytic activities over Zeolite Hβ supported iron catalyst (Fe/HZβ were compared both for the two catalytic routes. For SCO experiments; temperature (300-550 °C, O2 (2000-6000 ppmv and (0-10% H2 concentrations were investigated with the presence of 800 ppm NH3 in each of the final gas mixture. In the second route, catalytic ammonia decomposition experiments were carried out with H2 in balance N2 (0-30% containing 800 ppm NH3 at 700°C and 800°C. In the SCO, NH3 conversions were increased with increasing reaction temperatures with the absence of H2 in the reaction mixture. With 10% H2, it was shown that NH3 conversions increased with decreasing the reaction temperature. This was interpreted as the competing H2 and NH3 oxidations over the catalyst. On the other hand, in the catalytic decomposition, thermodynamic equilibrium conversion of almost 100% was attained at both 700 and 800 °C. Upon H2 addition, all conversions decreased. The decrease in conversion seemed to be linear with inlet hydrogen concentration. Hydrogen was seen to inhibit ammonia decomposition reaction. It was shown that Fe/HZβ catalyst is better to use for catalytic decomposition of NH3 in syngas rather than SCO of NH3 in spite of higher reaction temperatures needed in the decomposition reaction.

Microbial community shifts and biogas conversion computation during steady, inhibited and recovered stages of thermophilic methane fermentation on chicken manure with a wide variation of ammonia.

Science.gov (United States)

Niu, Qigui; Qiao, Wei; Qiang, Hong; Li, Yu-You

2013-10-01

The thermophilic methane fermentation of chicken manure (10% TS) was investigated within a wide range of ammonia. Microbiological analysis showed significant shifts in Archaeal and Bacterial proportions with VFA accmulation and CH4 formation before and after inhibition. VFA accumulated sharply with lower methane production, 0.29 L/g VS, than during the steady stage, 0.32 L/g VS. Biogas production almost ceased with the synergy inhibition of TAN (8000 mg/L) and VFA (25,000 mg/L). Hydrogenotrophic Methanothermobacter thermautotrophicus str. was the dominate archaea with 95% in the inhibition stage and 100% after 40 days recovery compared to 9.3% in the steady stage. Aceticlastic Methanosarcina was not encountered with coincided phenomenal of high VFA in the inhibition stage as well as recovery stage. Evaluation of the microbial diversity and functional bacteria indicated the dominate phylum of Firmicutes were 94.74% and 84.4% with and without inhibition. The microbial community shifted significantly with elevated ammonia concentration affecting the performance. Copyright © 2013 Elsevier Ltd. All rights reserved.

Consumption of ammonia-nitrogen by aob in immobilized batch ...

African Journals Online (AJOL)

This study investigated the performance of bio-filters immobilized nitrifying bacteria, ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB). In particular, it was to assess the consumption of ammonia-nitrogen (NH3-N) by the AOB. The experiment was conducted in a one litre reactor.The reactor consisted of ...

Effects of inorganic carbon on the nitrous oxide emissions and microbial diversity of an anaerobic ammonia oxidation reactor.

Science.gov (United States)

Zhang, Wenjie; Wang, Dunqiu; Jin, Yue

2018-02-01

Inorganic carbon (IC) is important for anaerobic ammonium oxidation (anammox). In this study, the effects of the IC concentration on N 2 O emissions and microbial diversity in an anammox reactor were investigated. N 2 O emissions were positively correlated with IC concentrations, and IC concentrations in the range of 55-130 mg/L were optimal, considering the nitrogen removal rate and N 2 O emissions. High IC concentrations resulted in the formation of CaCO 3 on the surface of anammox granules, which impacted the diffusion conditions of the substrate. Microbial community analysis indicated that high IC concentrations decreased the populations of specific bacteria, such as Achromobacter spanius strain YJART-7, Achromobacter xylosoxidans strain IHB B 6801, and Denitratisoma oestradiolicum clone 20b_15. D. oestradiolicum clone 20b_15 appeared to be the key contributor to N 2 O emissions. High N 2 O emissions may result from changes in organic carbon sources, which lead to denitrification by D. oestradiolicum clone 20b_15. Copyright © 2017 Elsevier Ltd. All rights reserved.

Formation of Hydroxylamine on Dust Grains via Ammonia Oxidation

Science.gov (United States)

He, Jiao; Vidali, Gianfranco; Lemaire, Jean-Louis; Garrod, Robin T.

2015-01-01

The quest to detect prebiotic molecules in space, notably amino acids, requires an understanding of the chemistry involving nitrogen atoms. Hydroxylamine (NH2OH) is considered a precursor to the amino acid glycine. Although not yet detected, NH2OH is considered a likely target of detection with ALMA. We report on an experimental investigation of the formation of hydroxylamine on an amorphous silicate surface via the oxidation of ammonia. The experimental data are then fed into a simulation of the formation of NH2OH in dense cloud conditions. On ices at 14 K and with a modest activation energy barrier, NH2OH is found to be formed with an abundance that never falls below a factor 10 with respect to NH3. Suggestions of conditions for future observations are provided.

Study on treatment of distilled ammonia waste water from coke plant with activated carbon-NaClO catalytic oxidation method

Energy Technology Data Exchange (ETDEWEB)

Luo, D.; Yi, P.; Liu, J.; Chen, A. [Xiangtan Polytechnic University, Xiangtan (China). Dept. of Chemical Enginering

2001-12-01

Catalytic oxidation method for the treatment of distilled ammonia waste water from coke plant was investigated using activated carbon as catalyst and NaClO as oxidant. The influences of main factors, such as NaClO, activated carbon, pH and reactionary time were discussed. The results showed that under the conditions of 25{degree}C, NaClO/CODO=1.5, carbon/NaClO=0.6 and pH=3.0, the reaction completed within 120 minutes with 99.5% of phenol removal and 75.8% of COD removal when the distilled ammonia waste water from coke plant which containing phenol 510 mg/L and CODO 8420 mg/L was treated. 13 refs., 4 figs.

Constraints on mechanisms and rates of anaerobic oxidation of methane by microbial consortia: process-based modeling of ANME-2 archaea and sulfate reducing bacteria interactions

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B. Orcutt

2008-11-01

Full Text Available Anaerobic oxidation of methane (AOM is the main process responsible for the removal of methane generated in Earth's marine subsurface environments. However, the biochemical mechanism of AOM remains elusive. By explicitly resolving the observed spatial arrangement of methanotrophic archaea and sulfate reducing bacteria found in consortia mediating AOM, potential intermediates involved in the electron transfer between the methane oxidizing and sulfate reducing partners were investigated via a consortium-scale reaction transport model that integrates the effect of diffusional transport with thermodynamic and kinetic controls on microbial activity. Model simulations were used to assess the impact of poorly constrained microbial characteristics such as minimum energy requirements to sustain metabolism and cell specific rates. The role of environmental conditions such as the influence of methane levels on the feasibility of H₂, formate and acetate as intermediate species, and the impact of the abundance of intermediate species on pathway reversal were examined. The results show that higher production rates of intermediates via AOM lead to increased diffusive fluxes from the methane oxidizing archaea to sulfate reducing bacteria, but the build-up of the exchangeable species can cause the energy yield of AOM to drop below that required for ATP production. Comparison to data from laboratory experiments shows that under the experimental conditions of Nauhaus et al. (2007, none of the potential intermediates considered here is able to support metabolic activity matching the measured rates.

A Phylogenomic Census of Molecular Functions Identifies Modern Thermophilic Archaea as the Most Ancient Form of Cellular Life

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Arshan Nasir

2014-01-01

Full Text Available The origins of diversified life remain mysterious despite considerable efforts devoted to untangling the roots of the universal tree of life. Here we reconstructed phylogenies that described the evolution of molecular functions and the evolution of species directly from a genomic census of gene ontology (GO definitions. We sampled 249 free-living genomes spanning organisms in the three superkingdoms of life, Archaea, Bacteria, and Eukarya, and used the abundance of GO terms as molecular characters to produce rooted phylogenetic trees. Results revealed an early thermophilic origin of Archaea that was followed by genome reduction events in microbial superkingdoms. Eukaryal genomes displayed extraordinary functional diversity and were enriched with hundreds of novel molecular activities not detected in the akaryotic microbial cells. Remarkably, the majority of these novel functions appeared quite late in evolution, synchronized with the diversification of the eukaryal superkingdom. The distribution of GO terms in superkingdoms confirms that Archaea appears to be the simplest and most ancient form of cellular life, while Eukarya is the most diverse and recent.

A phylogenomic census of molecular functions identifies modern thermophilic archaea as the most ancient form of cellular life.

Science.gov (United States)

Nasir, Arshan; Kim, Kyung Mo; Caetano-Anollés, Gustavo

2014-01-01

The origins of diversified life remain mysterious despite considerable efforts devoted to untangling the roots of the universal tree of life. Here we reconstructed phylogenies that described the evolution of molecular functions and the evolution of species directly from a genomic census of gene ontology (GO) definitions. We sampled 249 free-living genomes spanning organisms in the three superkingdoms of life, Archaea, Bacteria, and Eukarya, and used the abundance of GO terms as molecular characters to produce rooted phylogenetic trees. Results revealed an early thermophilic origin of Archaea that was followed by genome reduction events in microbial superkingdoms. Eukaryal genomes displayed extraordinary functional diversity and were enriched with hundreds of novel molecular activities not detected in the akaryotic microbial cells. Remarkably, the majority of these novel functions appeared quite late in evolution, synchronized with the diversification of the eukaryal superkingdom. The distribution of GO terms in superkingdoms confirms that Archaea appears to be the simplest and most ancient form of cellular life, while Eukarya is the most diverse and recent.

Diversity, biological roles and biosynthetic pathways for sugar-glycerate containing compatible solutes in bacteria and archaea.

Science.gov (United States)

Empadinhas, Nuno; da Costa, Milton S

2011-08-01

A decade ago the compatible solutes mannosylglycerate (MG) and glucosylglycerate (GG) were considered to be rare in nature. Apart from two species of thermophilic bacteria, Thermus thermophilus and Rhodothermus marinus, and a restricted group of hyperthermophilic archaea, the Thermococcales, MG had only been identified in a few red algae. Glucosylglycerate was considered to be even rarer and had only been detected as an insignificant solute in two halophilic microorganisms, a cyanobacterium, as a component of a polysaccharide and of a glycolipid in two actinobacteria. Unlike the hyper/thermophilic MG-accumulating microorganisms, branching close to the root of the Tree of Life, those harbouring GG shared a mesophilic lifestyle. Exceptionally, the thermophilic bacterium Persephonella marina was reported to accumulate GG. However, and especially owing to the identification of the key-genes for MG and GG synthesis and to the escalating numbers of genomes available, a plethora of new organisms with the resources to synthesize these solutes has been recognized. The accumulation of GG as an 'emergency' compatible solute under combined salt stress and nitrogen-deficient conditions now seems to be a disseminated survival strategy from enterobacteria to marine cyanobacteria. In contrast, the thermophilic and extremely radiation-resistant bacterium Rubrobacter xylanophilus is the only actinobacterium known to accumulate MG, and under all growth conditions tested. This review addresses the environmental factors underlying the accumulation of MG, GG and derivatives in bacteria and archaea and their roles during stress adaptation or as precursors for more elaborated macromolecules. The diversity of pathways for MG and GG synthesis as well as those for some of their derivatives is also discussed. The importance of glycerate-derived organic solutes in the microbial world is only now being recognized. Their stress-dependent accumulation and the molecular aspects of their

Effect of freshwater mussels on the vertical distribution of anaerobic ammonia oxidizers and other nitrogen-transforming microorganisms in upper Mississippi river sediment

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Ellen M. Black

2017-07-01

Full Text Available Targeted qPCR and non-targeted amplicon sequencing of 16S rRNA genes within sediment layers identified the anaerobic ammonium oxidation (anammox niche and characterized microbial community changes attributable to freshwater mussels. Anammox bacteria were normally distributed (Shapiro-Wilk normality test, W-statistic =0.954, p = 0.773 between 1 and 15 cm depth and were increased by a factor of 2.2 (p < 0.001 at 3 cm below the water-sediment interface when mussels were present. Amplicon sequencing of sediment at depths relevant to mussel burrowing (3 and 5 cm showed that mussel presence reduced observed species richness (p = 0.005, Chao1 diversity (p = 0.005, and Shannon diversity (p < 0.001, with more pronounced decreases at 5 cm depth. A non-metric, multidimensional scaling model showed that intersample microbial species diversity varied as a function of mussel presence, indicating that sediment below mussels harbored distinct microbial communities. Mussel presence corresponded with a 4-fold decrease in a majority of operational taxonomic units (OTUs classified in the phyla Gemmatimonadetes, Actinobacteria, Acidobacteria, Plantomycetes, Chloroflexi, Firmicutes, Crenarcheota, and Verrucomicrobia. 38 OTUs in the phylum Nitrospirae were differentially abundant (p < 0.001 with mussels, resulting in an overall increase from 25% to 35%. Nitrogen (N-cycle OTUs significantly impacted by mussels belonged to anammmox genus Candidatus Brocadia, ammonium oxidizing bacteria family Nitrosomonadaceae, ammonium oxidizing archaea genus Candidatus Nitrososphaera, nitrite oxidizing bacteria in genus Nitrospira, and nitrate- and nitrite-dependent anaerobic methane oxidizing organisms in the archaeal family “ANME-2d” and bacterial phylum “NC10”, respectively. Nitrosomonadaceae (0.9-fold (p < 0.001 increased with mussels, while NC10 (2.1-fold (p < 0.001, ANME-2d (1.8-fold (p < 0.001, and Candidatus Nitrososphaera (1.5-fold (p < 0

Catalytic reduction of nitric oxide with ammonia over transition metal ion-exchanged Y zeolites

Energy Technology Data Exchange (ETDEWEB)

Sciyama, T; Arakawa, T; Matsuda, T; Yamazoe, N; Takita, Y

1975-01-01

The catalytic reduction of nitric oxide with ammonia was studied over transition metal ion-exchanged Y zeolite (Me-Y) catalysts. The reaction products are nitrogen, nitrous oxide, and water in all cases. Selectivities to N/sub 2/ are 60 to 80% on all the cation exchanged zeolite catalysts exhibiting a relatively minor variation with the cationic species exchanged. The copper (II)-Y catalyst exhibits low temperature activity and has an unusual catalytic activity-temperature profile with a maximum at 120/sup 0/C. The catalytic activity is enhanced considerably when a second cation, especially cobalt (II) or iron (III) is coexchanged together with Cu (II) in Y zeolite.

Electrochemical oxidation of ammonia-containing wastewater using Ti/RuO2-Pt electrode

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Wei-wu Hu

2009-12-01

Full Text Available The electrochemical oxidation degradation processes for artificial and actual wastewater containing ammonia were carried out with a Ti/RuO2-Pt anode and a Ti plate cathode. We studied the effects of different current densities, space sizes between the two electrodes, and amounts of added NaCl on ammonia-containing wastewater treatment. It was shown that, after a 30-min treatment under the optimal conditions, which were a current density of 20 mA/cm2, a space size between the two electrodes of 1 cm, and an added amount of 0.5 g/L of NaCl, the COD concentration in municipal wastewater was 40 mg/L, a removal rate of 90%; and the NH3-N concentration was 7 mg/L, a removal rate of 88.3%. The effluent of municipal wastewater qualified for Class A of the Discharge Standard of Pollutants for Municipal Wastewater Treatment Plant (GB18918-2002.

Computational Exploration of Putative LuxR Solos in Archaea and Their Functional Implications in Quorum Sensing

Science.gov (United States)

Rajput, Akanksha; Kumar, Manoj

2017-01-01

LuxR solos are unexplored in Archaea, despite their vital role in the bacterial regulatory network. They assist bacteria in perceiving acyl homoserine lactones (AHLs) and/or non-AHLs signaling molecules for establishing intraspecies, interspecies, and interkingdom communication. In this study, we explored the potential LuxR solos of Archaea from InterPro v62.0 meta-database employing taxonomic, probable function, distribution, and evolutionary aspects to decipher their role in quorum sensing (QS). Our bioinformatics analyses showed that putative LuxR solos of Archaea shared few conserved domains with bacterial LuxR despite having less similarity within proteins. Functional characterization revealed their ability to bind various AHLs and/or non-AHLs signaling molecules that involve in QS cascades alike bacteria. Further, the phylogenetic study indicates that Archaeal LuxR solos (with less substitution per site) evolved divergently from bacteria and share distant homology along with instances of horizontal gene transfer. Moreover, Archaea possessing putative LuxR solos, exhibit the correlation between taxonomy and ecological niche despite being the inhabitant of diverse habitats like halophilic, thermophilic, barophilic, methanogenic, and chemolithotrophic. Therefore, this study would shed light in deciphering the role of the putative LuxR solos of Archaea to adapt varied habitats via multilevel communication with other organisms using QS. PMID:28515720

Computational Exploration of Putative LuxR Solos in Archaea and Their Functional Implications in Quorum Sensing

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Akanksha Rajput

2017-05-01

Full Text Available LuxR solos are unexplored in Archaea, despite their vital role in the bacterial regulatory network. They assist bacteria in perceiving acyl homoserine lactones (AHLs and/or non-AHLs signaling molecules for establishing intraspecies, interspecies, and interkingdom communication. In this study, we explored the potential LuxR solos of Archaea from InterPro v62.0 meta-database employing taxonomic, probable function, distribution, and evolutionary aspects to decipher their role in quorum sensing (QS. Our bioinformatics analyses showed that putative LuxR solos of Archaea shared few conserved domains with bacterial LuxR despite having less similarity within proteins. Functional characterization revealed their ability to bind various AHLs and/or non-AHLs signaling molecules that involve in QS cascades alike bacteria. Further, the phylogenetic study indicates that Archaeal LuxR solos (with less substitution per site evolved divergently from bacteria and share distant homology along with instances of horizontal gene transfer. Moreover, Archaea possessing putative LuxR solos, exhibit the correlation between taxonomy and ecological niche despite being the inhabitant of diverse habitats like halophilic, thermophilic, barophilic, methanogenic, and chemolithotrophic. Therefore, this study would shed light in deciphering the role of the putative LuxR solos of Archaea to adapt varied habitats via multilevel communication with other organisms using QS.

Response of archaeal communities in the rhizosphere of maize and soybean to elevated atmospheric CO2 concentrations.

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David M Nelson

Full Text Available BACKGROUND: Archaea are important to the carbon and nitrogen cycles, but it remains uncertain how rising atmospheric carbon dioxide concentrations ([CO(2] will influence the structure and function of soil archaeal communities. METHODOLOGY/PRINCIPAL FINDINGS: We measured abundances of archaeal and bacterial 16S rRNA and amoA genes, phylogenies of archaeal 16S rRNA and amoA genes, concentrations of KCl-extractable soil ammonium and nitrite, and potential ammonia oxidation rates in rhizosphere soil samples from maize and soybean exposed to ambient (∼385 ppm and elevated (550 ppm [CO(2] in a replicated and field-based study. There was no influence of elevated [CO(2] on copy numbers of archaeal or bacterial 16S rRNA or amoA genes, archaeal community composition, KCl-extractable soil ammonium or nitrite, or potential ammonia oxidation rates for samples from maize, a model C(4 plant. Phylogenetic evidence indicated decreased relative abundance of crenarchaeal sequences in the rhizosphere of soybean, a model leguminous-C(3 plant, at elevated [CO(2], whereas quantitative PCR data indicated no changes in the absolute abundance of archaea. There were no changes in potential ammonia oxidation rates at elevated [CO(2] for soybean. Ammonia oxidation rates were lower in the rhizosphere of maize than soybean, likely because of lower soil pH and/or abundance of archaea. KCl-extractable ammonium and nitrite concentrations were lower at elevated than ambient [CO(2] for soybean. CONCLUSION: Plant-driven shifts in soil biogeochemical processes in response to elevated [CO(2] affected archaeal community composition, but not copy numbers of archaeal genes, in the rhizosphere of soybean. The lack of a treatment effect for maize is consistent with the fact that the photosynthesis and productivity of maize are not stimulated by elevated [CO(2] in the absence of drought.

Ammonia-oxidizing activity and microbial community structure in acid tea (Camellia sinensis) orchard soil

International Nuclear Information System (INIS)

Okamura, K; Yamada, T; Hiraishi, A; Takanashi, A

2012-01-01

The purpose of this study was to determine the ammonia-oxidizing activity and the phylogentic composition of microorganisms involved in acid tea (Camellia sinensis) orchard soil. All soil samples were collected from three sites located in Tahara and Toyohashi, Aichi Prefecture, Japan. The potential nitrification rate (PNR) was measured by the chlorate inhibition method. The soil pH of tea orchards studied ranged from 2.78 to 4.84, differing significantly from sample to sample, whereas that of meadow and unplanted fields ranged from 5.78 to 6.35. The PNR ranged from 0.050 to 0.193 μg NO 2 - -Ng -1 h -1 and were positively correlated with the soil pH (r 2 0.382, p 2 - -Ng -1 h -1 ) and subjected to PCR-aided clone library analyses targeting archaeal and bacterial amoA genes. The detected archaeal clones separated from the cluster of the 'Soil clones' and tightly clustered with the clones originating from other acidic soil environments including the Chinese tea orchard soil. These results suggest that the specific archaeal populations dominate as the ammonia oxidizers in acid tea-orchard soils and possibly other acid soils, independent of geographic locations, which results from the adaptation to specific ecological niches.

Archaea: Essential inhabitants of the human digestive microbiota

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Vanessa Demonfort Nkamga

2017-03-01

Full Text Available Prokaryotes forming the domain of Archaea, named after their first discovery in extreme environments, are acknowledged but still neglected members of the human digestive tract microbiota. In this microbiota, cultured archaea comprise anaerobic methanogens: Methanobrevibacter smithii, Methanobrevibacter oralis, Methanobrevibacter massiliense, Methanosphaera stadtmanae, Methanobrevibacter arboriphilus, Methanobrevibacter millerae and Methanomassiliicoccus luminyensis; along with the non-methanogen halophilic Archaea Halopherax massiliense. Metagenomic analyses detected DNA sequences indicative of the presence of additional methanogenic and non-methanogenic halophilic Archaea in the human intestinal tract and oral cavity. Methanogens specifically metabolize hydrogen produced by anaerobic fermentation of carbohydrates into methane; further transforming heavy metals and metalloids into methylated derivatives, such as trimethylbismuth which is toxic for both human and bacterial cells. However, the role of Archaea as pathogens remains to be established. Future researches will aim to increase the repertoire of the human digestive tract Archaea and to understand their possible association with intestinal and extra-intestinal infections and diseases including weight regulation abnormalities. Keywords: Human-associated Archaea, Methanogens, Halophiles, Oral cavity, Intestinal tract

Resistance of extremely halophilic archaea to zinc and zinc oxide nanoparticles

Science.gov (United States)

Salgaonkar, Bhakti B.; Das, Deepthi; Bragança, Judith Maria

2016-02-01

Industrialization as well as other anthropogenic activities have resulted in addition of high loads of metal and/or metal nanoparticles to the environment. In this study, the effect of one of the widely used heavy metal, zinc (Zn) and zinc oxide nanoparticles (ZnO NPs) on extremely halophilic archaea was evaluated. One representative member from four genera namely Halococcus, Haloferax, Halorubrum and Haloarcula of the family Halobacteriaceae was taken as the model organism. All the haloarchaeal genera investigated were resistant to both ZnCl2 and ZnO NPs at varying concentrations. Halococcus strain BK6 and Haloferax strain BBK2 showed the highest resistance in complex/minimal medium of up to 2.0/1.0 mM ZnCl2 and 2.0/1.0-0.5 mM ZnO NP. Accumulation of ZnCl2/ZnO NPs was seen as Haloferax strain BBK2 (287.2/549.6 mg g-1) > Halococcus strain BK6 (165.9/388.5 mg g-1) > Haloarcula strain BS2 (93.2/28.5 mg g-1) > Halorubrum strain BS17 (29.9/16.2 mg g-1). Scanning electron microscopy and energy dispersive X-ray spectroscopy (SEM-EDX) analysis revealed that bulk ZnCl2 was sorbed at a higher concentration (21.77 %) on the cell surface of Haloferax strain BBK2 as compared to the ZnO NPs (14.89 %).

Laboratory-Scale Demonstration Using Dilute Ammonia Gas-Induced Alkaline Hydrolysis of Soil Contaminants (Chlorinated Propanes and Explosives)

Science.gov (United States)

2016-06-01

stabilization of metals (like Cr (VI)) and radionuclides ( uranium or technetium) (Thornton and Amonette 1999, Thornton et al. 2007). Master variable...successful at significantly reducing uranium mobility, although the effect was somewhat reversible. Ammonia oxidation and remediation Ammonia...activity of ammonia- oxidizing microorganisms. A 283-day experiment did not result in any measureable increase in ammonia- oxidizing microorganisms

FORMATION OF HYDROXYLAMINE ON DUST GRAINS VIA AMMONIA OXIDATION

Energy Technology Data Exchange (ETDEWEB)

He, Jiao; Vidali, Gianfranco [Physics Department, Syracuse University, Syracuse, NY 13244 (United States); Lemaire, Jean-Louis [Paris Observatory, F-75014 Paris (France); Garrod, Robin T., E-mail: gvidali@syr.edu [Center for Radiophysics and Space Research, Cornell University, Ithaca, NY 14853 (United States)

2015-01-20

The quest to detect prebiotic molecules in space, notably amino acids, requires an understanding of the chemistry involving nitrogen atoms. Hydroxylamine (NH{sub 2}OH) is considered a precursor to the amino acid glycine. Although not yet detected, NH{sub 2}OH is considered a likely target of detection with ALMA. We report on an experimental investigation of the formation of hydroxylamine on an amorphous silicate surface via the oxidation of ammonia. The experimental data are then fed into a simulation of the formation of NH{sub 2}OH in dense cloud conditions. On ices at 14 K and with a modest activation energy barrier, NH{sub 2}OH is found to be formed with an abundance that never falls below a factor 10 with respect to NH{sub 3}. Suggestions of conditions for future observations are provided.

A Metagenomics-Based Metabolic Model of Nitrate-Dependent Anaerobic Oxidation of Methane by Methanoperedens-Like Archaea

Science.gov (United States)

Arshad, Arslan; Speth, Daan R.; de Graaf, Rob M.; Op den Camp, Huub J. M.; Jetten, Mike S. M.; Welte, Cornelia U.

2015-01-01

Methane oxidation is an important process to mitigate the emission of the greenhouse gas methane and further exacerbating of climate forcing. Both aerobic and anaerobic microorganisms have been reported to catalyze methane oxidation with only a few possible electron acceptors. Recently, new microorganisms were identified that could couple the oxidation of methane to nitrate or nitrite reduction. Here we investigated such an enrichment culture at the (meta) genomic level to establish a metabolic model of nitrate-driven anaerobic oxidation of methane (nitrate-AOM). Nitrate-AOM is catalyzed by an archaeon closely related to (reverse) methanogens that belongs to the ANME-2d clade, tentatively named Methanoperedens nitroreducens. Methane may be activated by methyl-CoM reductase and subsequently undergo full oxidation to carbon dioxide via reverse methanogenesis. All enzymes of this pathway were present and expressed in the investigated culture. The genome of the archaeal enrichment culture encoded a variety of enzymes involved in an electron transport chain similar to those found in Methanosarcina species with additional features not previously found in methane-converting archaea. Nitrate reduction to nitrite seems to be located in the pseudoperiplasm and may be catalyzed by an unusual Nar-like protein complex. A small part of the resulting nitrite is reduced to ammonium which may be catalyzed by a Nrf-type nitrite reductase. One of the key questions is how electrons from cytoplasmically located reverse methanogenesis reach the nitrate reductase in the pseudoperiplasm. Electron transport in M. nitroreducens probably involves cofactor F420 in the cytoplasm, quinones in the cytoplasmic membrane and cytochrome c in the pseudoperiplasm. The membrane-bound electron transport chain includes F420H2 dehydrogenase and an unusual Rieske/cytochrome b complex. Based on genome and transcriptome studies a tentative model of how central energy metabolism of nitrate-AOM could work is

Modeling of nitrous oxide production by autotrophic ammonia-oxidizing bacteria with multiple production pathways.

Science.gov (United States)

Ni, Bing-Jie; Peng, Lai; Law, Yingyu; Guo, Jianhua; Yuan, Zhiguo

2014-04-01

Autotrophic ammonia oxidizing bacteria (AOB) have been recognized as a major contributor to N2O production in wastewater treatment systems. However, so far N2O models have been proposed based on a single N2O production pathway by AOB, and there is still a lack of effective approach for the integration of these models. In this work, an integrated mathematical model that considers multiple production pathways is developed to describe N2O production by AOB. The pathways considered include the nitrifier denitrification pathway (N2O as the final product of AOB denitrification with NO2(-) as the terminal electron acceptor) and the hydroxylamine (NH2OH) pathway (N2O as a byproduct of incomplete oxidation of NH2OH to NO2(-)). In this model, the oxidation and reduction processes are modeled separately, with intracellular electron carriers introduced to link the two types of processes. The model is calibrated and validated using experimental data obtained with two independent nitrifying cultures. The model satisfactorily describes the N2O data from both systems. The model also predicts shifts of the dominating pathway at various dissolved oxygen (DO) and nitrite levels, consistent with previous hypotheses. This unified model is expected to enhance our ability to predict N2O production by AOB in wastewater treatment systems under varying operational conditions.

Plant Community and Nitrogen Deposition as Drivers of Alpha and Beta Diversities of Prokaryotes in Reconstructed Oil Sand Soils and Natural Boreal Forest Soils

Science.gov (United States)

Prescott, Cindy E.; Renaut, Sébastien; Terrat, Yves; Grayston, Sue J.

2017-01-01

ABSTRACT The Athabasca oil sand deposit is one of the largest single oil deposits in the world. Following surface mining, companies are required to restore soil-like profiles that can support the previous land capabilities. The objective of this study was to assess whether the soil prokaryotic alpha diversity (α-diversity) and β-diversity in oil sand soils reconstructed 20 to 30 years previously and planted to one of three vegetation types (coniferous or deciduous trees and grassland) were similar to those found in natural boreal forest soils subject to wildfire disturbance. Prokaryotic α-diversity and β-diversity were assessed using massively parallel sequencing of 16S rRNA genes. The β-diversity, but not the α-diversity, differed between reconstructed and natural soils. Bacteria associated with an oligotrophic lifestyle were more abundant in natural forest soils, whereas bacteria associated with a copiotrophic lifestyle were more abundant in reconstructed soils. Ammonia-oxidizing archaea were most abundant in reconstructed soils planted with grasses. Plant species were the main factor influencing α-diversity in natural and in reconstructed soils. Nitrogen deposition, pH, and plant species were the main factors influencing the β-diversity of the prokaryotic communities in natural and reconstructed soils. The results highlight the importance of nitrogen deposition and aboveground-belowground relationships in shaping soil microbial communities in natural and reconstructed soils. IMPORTANCE Covering over 800 km2, land disturbed by the exploitation of the oil sands in Canada has to be restored. Here, we take advantage of the proximity between these reconstructed ecosystems and the boreal forest surrounding the oil sand mining area to study soil microbial community structure and processes in both natural and nonnatural environments. By identifying key characteristics shaping the structure of soil microbial communities, this study improved our understanding of

Regulation of transcription in hyperthermophilic archaea

NARCIS (Netherlands)

Brinkman, A.B.

2002-01-01

The aim of the research presented here was to insight in the mechanisms by which transcription in hyperthermophilic archaea is regulated. To accomplish this, we have aimed (I) to identify transcriptional regulatory proteins from hyperthermophilic archaea, (II) to characterize these

Probing the electronic structure of M-graphene oxide (M = Ni, Co, NiCo) catalysts for hydrolytic dehydrogenation of ammonia borane

Energy Technology Data Exchange (ETDEWEB)

Zhao, Binhua; Liu, Jinyin; Zhou, Litao [Soochow University-Western University Centre for Synchrotron Radiation Research, Institute of Functional Nano and Soft Material (FUNSOM) and Collaborative Innovation Center of Suzhou Nano Science & Technology, Soochow University, Suzhou 215123 (China); Long, Dan, E-mail: legend_long@aliyun.com [Department of Radiology, Zhejiang Cancer Hospital, Hangzhou 310022 (China); Feng, Kun; Sun, Xuhui [Soochow University-Western University Centre for Synchrotron Radiation Research, Institute of Functional Nano and Soft Material (FUNSOM) and Collaborative Innovation Center of Suzhou Nano Science & Technology, Soochow University, Suzhou 215123 (China); Zhong, Jun, E-mail: jzhong@suda.edu.cn [Soochow University-Western University Centre for Synchrotron Radiation Research, Institute of Functional Nano and Soft Material (FUNSOM) and Collaborative Innovation Center of Suzhou Nano Science & Technology, Soochow University, Suzhou 215123 (China)

2016-01-30

Graphical abstract: An interaction between metal and graphene oxide was probed to enhance the hydrolysis efficiency of ammonia borane. - Highlights: • Various metal elements (M = Ni, Co, NiCo) were dispersed on graphene oxide (GO) for the hydrolysis of ammonia borane (AB). • The electronic structure of the hybrids has been probed by scanning transmission X-ray microscopy (STXM). • An interfacial interaction between metal and GO was observed which could be related to the hydrolysis performance. • The results provide new insight into the enhanced performance of the M-GO hybrids. - Abstract: Various metal elements (M = Ni, Co, NiCo) were dispersed on graphene oxide (GO) to form the M-GO hybrids by a facile way. The hybrids showed good catalytic activities in the hydrolytic dehydrogenation of ammonia borane (AB, NH{sub 3}BH{sub 3}), which were significantly enhanced when compared to the metal nanoparticles or GO alone. The electronic structure of the hybrids has been probed by scanning transmission X-ray microscopy (STXM). The distribution of metal elements was clearly imaged with identical electronic structure. Moreover, an interfacial interaction between metal and GO was observed with the peak intensity proportional to the catalytic performance in the hydrolysis of AB. The results provide new insight into the enhanced performance of the M-GO hybrids and may help for the design of advanced catalysts.

Calcium in the Mechanism of Ammonia-Induced Astrocyte Swelling

Science.gov (United States)

Jayakumar, A.R.; Rao, K.V. Rama; Tong, X.Y; Norenberg, M.D.

2016-01-01

Brain edema, due largely to astrocyte swelling, is an important clinical problem in patients with acute liver failure. While mechanisms underlying astrocyte swelling in this condition are not fully understood, ammonia and associated oxidative/nitrosative stress (ONS) appear to be involved. Mechanisms responsible for the increase in reactive oxygen/nitrogen species (RONS) and their role in ammonia-induced astrocyte swelling, however, are poorly understood. Recent studies have demonstrated a transient increase in intracellular Ca2+ in cultured astrocytes exposed to ammonia. As Ca2+ is a known inducer of RONS, we investigated potential mechanisms by which Ca2+ may be responsible for the production of RONS and cell swelling in cultured astrocytes after treatment with ammonia. Exposure of cultured astrocytes to ammonia (5 mM) increased the formation of free radicals, including nitric oxide, and such increase was significantly diminished by treatment with the Ca2+ chelator BAPTA-AM. We then examined the activity of Ca2+-dependent enzymes that are known to generate RONS and found that ammonia significantly increased the activities of NADPH oxidase (NOX), constitutive nitric oxide synthase (cNOS) and phospholipase A2 (PLA2) and such increases in activity were significantly diminished by BAPTA. Pretreatment of cultures with 7-nitroindazole, apocyanin and quinacrine, respective inhibitors of cNOS, NOX and PLA2, all significantly diminished RONS production. Additionally, treatment of cultures with BAPTA or with inhibitors of cNOS, NOX and PLA2 reduced ammonia-induced astrocyte swelling. These studies suggest that the ammonia-induced rise in intracellular Ca2+ activates free radical producing enzymes that ultimately contribute to the mechanism of astrocyte swelling. PMID:19393035

Unique features of glycolysis in Archaea

NARCIS (Netherlands)

Verhees, C.H.; Kengen, S.W.M.; Tuininga, J.E.; Schut, G.J.; Adams, M.W.W.; Vos, de W.M.; Oost, van der J.

2003-01-01

An early divergence in evolution has resulted in two prokaryotic domains, the Bacteria and the Archaea. Whereas the central metabolic routes of bacteria and eukaryotes are generally well-conserved, variant pathways have developed in Archaea involving several novel enzymes with a distinct control. A

Influence of tropical leaf litter on nitrogen mineralization and community structure of ammonia-oxidizing bacteria

OpenAIRE

Diallo, M. D.; Guisse, A.; Sall, S. N.; Dick, R. P.; Assigbetsé, Komi; Dieng, A. L.; Chotte, Jean-Luc

2015-01-01

Description of the subject. The present study concerns the relationships among leaf litter decomposition, substrate quality, ammonia-oxidizing bacteria (AOB) community composition and nitrogen (N) availability. Decomposition of organic matter affects the biogeochemical cycling of carbon (C) and N. Since the composition of the soil microbial community can alter the physiological capacity of the community, it is timely to study the litter quality effect on N dynamic in ecosystems. Objectives. T...

Atmospheric cycles of nitrogen oxides and ammonia. [source strengths and destruction rates

Science.gov (United States)

Bottger, A.; Ehhalt, D. H.; Gravenhorst, G.

1981-01-01

The atmospheric cycles of nitrogenous trace compounds for the Northern and Southern Hemispheres are discussed. Source strengths and destruction rates for the nitrogen oxides: NO, NO2 and HNO3 -(NOX) and ammonia (NH3) are given as a function of latitude over continents and oceans. The global amounts of NOX-N and NH3-N produced annually in the period 1950 to 1975 (34 + 5 x one trillion g NOx-N/yr and 29 + or - 6 x one trillion g NH3-N/yr) are much less than previously assumed. Globally, natural and anthropogenic emissions are of similar magnitude. The NOx emission from anthropogenic sources is 1.5 times that from natural processes in the Northern Hemisphere, whereas in the Southern Hemisphere, it is a factor of 3 or 4 less. More than 80% of atmospheric ammonia seems to be derived from excrements of domestic animals, mostly by bulk deposition: 24 + or - 9 x one trillion g NO3 -N/yr and 21 + or - 9 x one trillion g NH4+-N/yr. Another fraction may be removed by absorption on vegetation and soils.

Chemical pathways for the formation of ammonia in Hanford wastes

Energy Technology Data Exchange (ETDEWEB)

Stock, L.M.; Pederson, L.R.

1997-09-01

This report reviews chemical reactions leading to the formation of ammonia in Hanford wastes. The general features of the chemistry of the organic compounds in the Hanford wastes are briefly outlined. The radiolytic and thermal free radical reactions that are responsible for the initiation and propagation of the oxidative degradation reactions of the nitrogen-containing complexants, trisodium HEDTA and tetrasodium EDTA, are outlined. In addition, the roles played by three different ionic reaction pathways for the oxidation of the same compounds and their degradation products are described as a prelude to the discussion of the formation of ammonia. The reaction pathways postulated for its formation are based on tank observations, laboratory studies with simulated and actual wastes, and the review of the scientific literature. Ammonia derives from the reduction of nitrite ion (most important), from the conversion of organic nitrogen in the complexants and their degradation products, and from radiolytic reactions of nitrous oxide and nitrogen (least important). Reduction of nitrite ions is believed to be the most important source of ammonia. Whether by radiolytic or thermal routes, nitrite reduction reactions proceed through nitrogen dioxide, nitric oxide, the nitrosyl anion, and the hyponitrite anion. Nitrite ion is also converted into hydroxylamine, another important intermediate on the pathway to form ammonia. These reaction pathways additionally result in the formation of nitrous oxide and molecular nitrogen, whereas hydrogen formation is produced in a separate reaction sequence.

Chemical pathways for the formation of ammonia in Hanford wastes

International Nuclear Information System (INIS)

Stock, L.M.; Pederson, L.R.

1997-09-01

This report reviews chemical reactions leading to the formation of ammonia in Hanford wastes. The general features of the chemistry of the organic compounds in the Hanford wastes are briefly outlined. The radiolytic and thermal free radical reactions that are responsible for the initiation and propagation of the oxidative degradation reactions of the nitrogen-containing complexants, trisodium HEDTA and tetrasodium EDTA, are outlined. In addition, the roles played by three different ionic reaction pathways for the oxidation of the same compounds and their degradation products are described as a prelude to the discussion of the formation of ammonia. The reaction pathways postulated for its formation are based on tank observations, laboratory studies with simulated and actual wastes, and the review of the scientific literature. Ammonia derives from the reduction of nitrite ion (most important), from the conversion of organic nitrogen in the complexants and their degradation products, and from radiolytic reactions of nitrous oxide and nitrogen (least important). Reduction of nitrite ions is believed to be the most important source of ammonia. Whether by radiolytic or thermal routes, nitrite reduction reactions proceed through nitrogen dioxide, nitric oxide, the nitrosyl anion, and the hyponitrite anion. Nitrite ion is also converted into hydroxylamine, another important intermediate on the pathway to form ammonia. These reaction pathways additionally result in the formation of nitrous oxide and molecular nitrogen, whereas hydrogen formation is produced in a separate reaction sequence

Archaea.

Science.gov (United States)

Eme, Laura; Doolittle, W Ford

2015-10-05

A headline on the front page of the New York Times for November 3, 1977, read "Scientists Discover a Way of Life That Predates Higher Organisms". The accompanying article described a spectacular claim by Carl Woese and George Fox to have discovered a third form of life, a new 'domain' that we now call Archaea. It's not that these microbes were unknown before, nor was it the case that their peculiarities had gone completely unnoticed. Indeed, Ralph Wolfe, in the same department at the University of Illinois as Woese, had already discovered how it was that methanogens (uniquely on the planet) make methane, and the bizarre adaptations that allow extremely halophilic archaea (then called halobacteria) and thermoacidophiles to live in the extreme environments where they do were already under investigation in many labs. But what Woese and Fox had found was that these organisms were related to each other not just in their 'extremophily' but also phylogenetically. And, most surprisingly, they were only remotely related to the rest of the prokaryotes, which we now call the domain Bacteria (Figure 1). Copyright © 2015 Elsevier Ltd. All rights reserved.

Ammonia-oxidizing activity and microbial community structure in acid tea (Camellia sinensis) orchard soil

Science.gov (United States)

Okamura, K.; Takanashi, A.; Yamada, T.; Hiraishi, A.

2012-03-01

The purpose of this study was to determine the ammonia-oxidizing activity and the phylogentic composition of microorganisms involved in acid tea (Camellia sinensis) orchard soil. All soil samples were collected from three sites located in Tahara and Toyohashi, Aichi Prefecture, Japan. The potential nitrification rate (PNR) was measured by the chlorate inhibition method. The soil pH of tea orchards studied ranged from 2.78 to 4.84, differing significantly from sample to sample, whereas that of meadow and unplanted fields ranged from 5.78 to 6.35. The PNR ranged from 0.050 to 0.193 μg NO2--Ng-1 h-1 and were positively correlated with the soil pH (r2 = 0.382, p<0.001). Bulk DNA was extracted from a tea orchard soil (pH 4.8; PNR, 0.078 μg NO2--Ng-1 h-1) and subjected to PCR-aided clone library analyses targeting archaeal and bacterial amoA genes. The detected archaeal clones separated from the cluster of the 'Soil clones' and tightly clustered with the clones originating from other acidic soil environments including the Chinese tea orchard soil. These results suggest that the specific archaeal populations dominate as the ammonia oxidizers in acid tea-orchard soils and possibly other acid soils, independent of geographic locations, which results from the adaptation to specific ecological niches.

Continuously Monocropped Jerusalem Artichoke Changed Soil Bacterial Community Composition and Ammonia-Oxidizing and Denitrifying Bacteria Abundances.

Science.gov (United States)

Zhou, Xingang; Wang, Zhilin; Jia, Huiting; Li, Li; Wu, Fengzhi

2018-01-01

Soil microbial communities have profound effects on the growth, nutrition and health of plants in agroecosystems. Understanding soil microbial dynamics in cropping systems can assist in determining how agricultural practices influence soil processes mediated by microorganisms. In this study, soil bacterial communities were monitored in a continuously monocropped Jerusalem artichoke (JA) system, in which JA was successively monocropped for 3 years in a wheat field. Soil bacterial community compositions were estimated by amplicon sequencing of the 16S rRNA gene. Abundances of ammonia-oxidizing and denitrifying bacteria were estimated by quantitative PCR analysis of the amoA , nirS , and nirK genes. Results showed that 1-2 years of monocropping of JA did not significantly impact the microbial alpha diversity, and the third cropping of JA decreased the microbial alpha diversity ( P < 0.05). Principal coordinates analysis and permutational multivariate analysis of variance analyses revealed that continuous monocropping of JA changed soil bacterial community structure and function profile ( P < 0.001). At the phylum level, the wheat field was characterized with higher relative abundances of Latescibacteria , Planctomycetes , and Cyanobacteria , the first cropping of JA with Actinobacteria , the second cropping of JA with Acidobacteria , Armatimonadetes , Gemmatimonadetes , and Proteobacteria . At the genus level, the first cropping of JA was enriched with bacterial species with pathogen-antagonistic and/or plant growth promoting potentials, while members of genera that included potential denitrifiers increased in the second and third cropping of JA. The first cropping of JA had higher relative abundances of KO terms related to lignocellulose degradation and phosphorus cycling, the second cropping of JA had higher relative abundances of KO terms nitrous-oxide reductase and nitric-oxide reductase, and the third cropping of JA had higher relative abundances of KO terms

Continuously Monocropped Jerusalem Artichoke Changed Soil Bacterial Community Composition and Ammonia-Oxidizing and Denitrifying Bacteria Abundances

Directory of Open Access Journals (Sweden)

Xingang Zhou

2018-04-01

Full Text Available Soil microbial communities have profound effects on the growth, nutrition and health of plants in agroecosystems. Understanding soil microbial dynamics in cropping systems can assist in determining how agricultural practices influence soil processes mediated by microorganisms. In this study, soil bacterial communities were monitored in a continuously monocropped Jerusalem artichoke (JA system, in which JA was successively monocropped for 3 years in a wheat field. Soil bacterial community compositions were estimated by amplicon sequencing of the 16S rRNA gene. Abundances of ammonia-oxidizing and denitrifying bacteria were estimated by quantitative PCR analysis of the amoA, nirS, and nirK genes. Results showed that 1–2 years of monocropping of JA did not significantly impact the microbial alpha diversity, and the third cropping of JA decreased the microbial alpha diversity (P < 0.05. Principal coordinates analysis and permutational multivariate analysis of variance analyses revealed that continuous monocropping of JA changed soil bacterial community structure and function profile (P < 0.001. At the phylum level, the wheat field was characterized with higher relative abundances of Latescibacteria, Planctomycetes, and Cyanobacteria, the first cropping of JA with Actinobacteria, the second cropping of JA with Acidobacteria, Armatimonadetes, Gemmatimonadetes, and Proteobacteria. At the genus level, the first cropping of JA was enriched with bacterial species with pathogen-antagonistic and/or plant growth promoting potentials, while members of genera that included potential denitrifiers increased in the second and third cropping of JA. The first cropping of JA had higher relative abundances of KO terms related to lignocellulose degradation and phosphorus cycling, the second cropping of JA had higher relative abundances of KO terms nitrous-oxide reductase and nitric-oxide reductase, and the third cropping of JA had higher relative abundances of KO

Numerical analysis on effect of aspect ratio of planar solid oxide fuel cell fueled with decomposed ammonia

Science.gov (United States)

Tan, Wee Choon; Iwai, Hiroshi; Kishimoto, Masashi; Brus, Grzegorz; Szmyd, Janusz S.; Yoshida, Hideo

2018-04-01

Planar solid oxide fuel cells (SOFCs) with decomposed ammonia are numerically studied to investigate the effect of the cell aspect ratio. The ammonia decomposer is assumed to be located next to the SOFCs, and the heat required for the endothermic decomposition reaction is supplied by the thermal radiation from the SOFCs. Cells with aspect ratios (ratios of the streamwise length to the spanwise width) between 0.130 and 7.68 are provided with the reactants at a constant mass flow rate. A parametric study is conducted by varying the cell temperature and fuel utility factor to investigate their effects on the cell performance in terms of the voltage efficiency. The effect of the heat supply to the ammonia decomposer is also studied. The developed model shows good agreement, in terms of the current-voltage curve, with the experimental data obtained from a short stack without parameter tuning. The simulation study reveals that the cell with the highest aspect ratio achieves the highest performance under furnace operation. On the other hand, the 0.750 aspect ratio cell with the highest voltage efficiency of 0.67 is capable of thermally sustaining the ammonia decomposers at a fuel utility of 0.80 using the thermal radiation from both sidewalls.

Cyanate as energy source for nitrifiers

DEFF Research Database (Denmark)

Palatinszky, Marton; Herbold, Craig; Jehmlich, Nico

2015-01-01

recognized energy sources that promote the aerobic growth of ammonia-oxidizing bacteria and archaea. Here we report the aerobic growth of a pure culture of the ammonia-oxidizing thaumarchaeote Nitrososphaera gargensis1 using cyanate as the sole source of energy and reductant; to our knowledge, the first...... organism known to do so. Cyanate, a potentially important source of reduced nitrogen in aquatic and terrestrial ecosystems2, is converted to ammonium and carbon dioxide in Nitrososphaera gargensis by a cyanase enzyme that is induced upon addition of this compound. Within the cyanase gene family...

Density and distribution of nitrifying guilds in rapid sand filters for drinking water production: Dominance of Nitrospira spp

DEFF Research Database (Denmark)

Tatari, Karolina; Musovic, Sanin; Gülay, Arda

2017-01-01

distribution of these guilds, filter material was sampled at four drinking water treatment plants (DWTPs) in parallel filters of the pre- and after-filtration stages at different locations and depths. The target guilds were quantified by qPCR targeting 16S rRNA and amoA genes. Total bacterial densities......We investigated the density and distribution of total bacteria, canonical Ammonia Oxidizing Bacteria (AOB) (Nitrosomonas plus Nitrosospira), Ammonia Oxidizing Archaea (AOA), as well as Nitrobacter and Nitrospira in rapid sand filters used for groundwater treatment. To investigate the spatial...

Promotion of catalytic performance by adding W into Pt/ZrO{sub 2} catalyst for selective catalytic oxidation of ammonia

Energy Technology Data Exchange (ETDEWEB)

Sun, Mengmeng [Institute of New Energy and Low-Carbon Technology, Sichuan University, Chengdu 610064, Sichuan (China); Wang, Suning; Li, Yuanshan [College of Chemical Engineering, Sichuan University, Chengdu 610064, Sichuan (China); Xu, Haidi, E-mail: xuhaidi@scu.edu.cn [Institute of New Energy and Low-Carbon Technology, Sichuan University, Chengdu 610064, Sichuan (China); Chen, Yaoqiang, E-mail: nic7501@scu.edu.cn [Institute of New Energy and Low-Carbon Technology, Sichuan University, Chengdu 610064, Sichuan (China); College of Chemical Engineering, Sichuan University, Chengdu 610064, Sichuan (China)

2017-04-30

Highlights: • The tungsten species weaken platinum-oxygen bond strength. • Pt{sup 0} was the active species of ammonia oxidation reaction in the low temperature. • Some PtO species could convert to Pt [111] beside WO{sub 3} species. - Abstract: Pt-WO{sub 3}/ZrO{sub 2} catalyst was prepared by co-impregnation method to improve the ammonia oxidation performance of Pt/ZrO{sub 2}. Differences in textural, structural, surface chemical states, redox properties and acid properties, together with the catalytic performance of Pt/ZrO{sub 2} and Pt-WO{sub 3}/ZrO{sub 2} catalysts were investigated systematically. The results of H{sub 2}-TPR revealed that higher reduction ability was possessed by Pt-WO{sub 3}/ZrO{sub 2} than that of Pt/ZrO{sub 2} due to the influence of tungsten on platinum. The XPS results showed that electron transfer from tungsten to platinum species made higher electron density around platinum. The TEM results revealed that the active lattice plane Pt[111] was obtained by modification of W species. Consequently, Pt-WO{sub 3}/ZrO{sub 2} exhibited obviously better ammonia oxidation performance compared with Pt/ZrO{sub 2}, the light-off temperature of NH{sub 3} shifted from 284 °C to 249 °C, the activation energy decreased from 113.4 kJ mol{sup −1} to 96.2 kJ mol{sup −1}.

Hydrogen bonding-mediated dehydrogenation in the ammonia borane combined graphene oxide systems

Science.gov (United States)

Kuang, Anlong; Liu, Taijuan; Kuang, Minquan; Yang, Ruifeng; Huang, Rui; Wang, Guangzhao; Yuan, Hongkuan; Chen, Hong; Yang, Xiaolan

2018-03-01

The dehydrogenation of ammonia borane (AB) adsorbed on three different graphene oxide (GO) sheets is investigated within the ab initio density functional theory. The energy barriers to direct combination the hydrogens of hydroxyl groups and the hydridic hydrogens of AB to release H2 are relatively high, indicating that the process is energetically unfavorable. Our theoretical study demonstrates that the dehydrogenation mechanism of the AB-GO systems has undergone two critical steps, first, there is the formation of the hydrogen bond (O-H-O) between two hydroxyl groups, and then, the hydrogen bond further react with the hydridic hydrogens of AB to release H2 with low reaction barriers.

Methane Production and Methanogenic Archaea in the Digestive Tracts of Millipedes (Diplopoda)

Science.gov (United States)

Šustr, Vladimír; Chroňáková, Alica; Semanová, Stanislava; Tajovský, Karel; Šimek, Miloslav

2014-01-01

Methane production by intestinal methanogenic Archaea and their community structure were compared among phylogenetic lineages of millipedes. Tropical and temperate millipedes of 35 species and 17 families were investigated. Species that emitted methane were mostly in the juliform orders Julida, Spirobolida, and Spirostreptida. The irregular phylogenetic distribution of methane production correlated with the presence of the methanogen-specific mcrA gene. The study brings the first detailed survey of methanogens’ diversity in the digestive tract of millipedes. Sequences related to Methanosarcinales, Methanobacteriales, Methanomicrobiales and some unclassified Archaea were detected using molecular profiling (DGGE). The differences in substrate preferences of the main lineages of methanogenic Archaea found in different millipede orders indicate that the composition of methanogen communities may reflect the differences in available substrates for methanogenesis or the presence of symbiotic protozoa in the digestive tract. We conclude that differences in methane production in the millipede gut reflect differences in the activity and proliferation of intestinal methanogens rather than an absolute inability of some millipede taxa to host methanogens. This inference was supported by the general presence of methanogenic activity in millipede faecal pellets and the presence of the 16S rRNA gene of methanogens in all tested taxa in the two main groups of millipedes, the Helminthophora and the Pentazonia. PMID:25028969

Anodic oxidation of ammonia in alkaline solutions at Pt/Pt electrodes. Hakkin denkyokujo ni okeru enkisei ammonia yoeki no anodo sanka

Energy Technology Data Exchange (ETDEWEB)

Takagi, Ryoichiro; Katsuta, Masahiro; Matsumoto, Tamotsu; Kobayashi, Yoshikazu; Asami, Yusaku; Hirano, Katsuhiko (Shibaura Inst. of Tech., Tokyo (Japan))

1989-01-05

Anodic oxidation of ammonia in alkaline solutions on Pt/Pt electrode, in which NH {sub 3} is oxidized producing N {sub 2}, is a promising reaction in application to a fuel cell and water treatment. In this study, the relations between electrode potential and adsorbed intermediates, reaction process were elucidated by potentiodynamic method and potential step method. In measurement, a transient memory device and a microprocessor were connected to an electrolysis device as a new method, then measurement of electric potential and current and integral calculation were perfromed at high speed. Active sites of electrode were covered by Pt NH {sub x}. Faradic current corresponds to the N {sub 2} evolution was shown markedly by anodic scanning. The relation between electrode potential and reaction process was revealed by potential step method. It is found that Pt-NH {sub 2} is the active intermediate for the N {sub 2} evolution, and when current shows maximum, its coverage is nearly 0.5. 15 refs., 7 figs.

Changes in the ammonia-oxidizing bacteria community in response to operational parameters during the treatment of anaerobic sludge digester supernatant.

Science.gov (United States)

Cydzik-Kwiatkowska, Agnieszka; Zielińska, Magdalena; Bernat, Katarzyna; Kulikowska, Dorota; Wojnowska-Baryła, Irena

2012-07-01

The understanding of the relationship between ammoniaoxidizing bacteria (AOB) communities in activated sludge and the operational treatment parameters supports the control of the treatment of ammonia-rich wastewater. The modifications of treatment parameters by alteration of the number and length of aerobic and anaerobic stages in the sequencing batch reactor (SBR) working cycle may influence the efficiency of ammonium oxidation and induce changes in the AOB community. Therefore, in the research, the impact of an SBR cycle mode with alternating aeration/ mixing conditions (7 h/1 h vs. 4 h/5.5 h) and volumetric exchange rate (n) on AOB abundance and diversity in activated sludge during the treatment of anaerobic sludge digester supernatant at limited oxygen concentration in the aeration stage (0.7 mg O2/l) was assessed. AOB diversity expressed by the Shannon-Wiener index (H') was determined by the cycle mode. At aeration/mixing stage lengths of 7 h/1 h, H' averaged 2.48 +/- 0.17, while at 4 h/ 5.5 h it was 2.35 +/- 0.16. At the given mode, AOB diversity decreased with increasing n. The cycle mode did not affect AOB abundance; however, a higher AOB abundance in activated sludge was promoted by decreasing the volumetric exchange rate. The sequences clustering with Nitrosospira sp. NpAV revealed the uniqueness of the AOB community and the simultaneously lower ability of adaptation of Nitrosospira sp. to the operational parameters applied in comparison with Nitrosomonas sp.

Archaeal Nitrification in Hot Springs

Science.gov (United States)

Richter, A.; Daims, H.; Reigstad, L.; Wanek, W.; Wagner, M.; Schleper, C.

2006-12-01

Biological nitrification, i.e. the aerobic conversion of ammonia to nitrate via nitrite, is a major component of the global nitrogen cycle. Until recently, it was thought that the ability to aerobically oxidize ammonia was confined to bacteria of the phylum Proteobacteria. However, it has recently been shown that Archaea of the phylum Crenarchaeota are also capable of ammonia oxidation. As many Crenarchaeota are thermophilic or hyperthermophilic, and at least some of them are capable of ammonia oxidation we speculated on the existence of (hyper)thermophilic ammonia-oxidizing archaea (AOA). Using PCR primers specifically targeting the archaeal ammonia monooxygenase (amoA) gene, we were indeed able to confirm the presence of such organisms in several hot springs in Reykjadalur, Iceland. These hot springs exhibited temperatures well above 80 °C and pH values ranging from 2.0 to 4.5. To proof that nitrification actually took place under these extreme conditions, we measured gross nitrification rates by the isotope pool dilution method; we added 15N-labelled nitrate to the mud and followed the dilution of the label by nitrate production from ammonium either in situ (incubation in the hot spring) or under controlled conditions in the laboratory (at 80 °C). The nitrification rates in the hot springs ranged from 0.79 to 2.22 mg nitrate-N per L of mud and day. Controls, in which microorganisms were killed before the incubations, demonstrated that the nitrification was of biological origin. Addition of ammonium increased the gross nitrification rate approximately 3-fold, indicating that the nitrification was ammonium limited under the conditions used. Collectively, our study provides evidence that (1) AOA are present in hot springs and (2) that they are actively nitrifying. These findings have major implications for our understanding of nitrogen cycling of hot environments.

Ammonia effect on hydrogenotrophic methanogens and syntrophic acetate oxidizing bacteria

DEFF Research Database (Denmark)

Wang, Han; Fotidis, Ioannis; Angelidaki, Irini

2015-01-01

tested in the study; which is contradicting to the general belief that thermophilic methanogens are more vulnerable to high ammonia loads compared to mesophilic. This unexpected finding underlines the fact that the complete knowledge of ammonia inhibition effect on hydrogenotrophic methanogens is still...

Methanogenic Archaea and oral infections – ways to unravel the black box

Directory of Open Access Journals (Sweden)

Hans-Peter Horz

2011-02-01

Full Text Available Archaea, organisms that make up the third domain of cellular life are members of the human oral microflora. They are strikingly less diverse than oral bacteria and appear to be relatively rare with respect to their numerical abundance. Since they have been exclusively found in association with oral infections such as periodontitis and apical periodontitis and given their unique physiology and energy metabolism, it is highly plausible that they are more than just secondary colonizers of infected areas, but instead are actively involved in the overall poly-microbial infection process. Conversely, it is a highly challenging task to clearly demonstrate their possible active participation – mostly due to the difficulty to grow them in routine microbiology laboratories. This current review points out the importance for understanding the medical impact of methanogens and aims at devising strategies for elucidating the true function of archaea in the oral ecosystem.

Ammonia gas sensing property of gadolinium oxide using fiber optic gas sensor

Science.gov (United States)

Kumar, J. Santhosh; Ranganathan, B.; Sastikumar, D.

2017-05-01

The design of fiber optic sensor is based on a cladding modification methodology. A fiber-optic chemical sensor is developed by replacing a certain portion of the original cladding with a chemically sensitive material, specifically, calcinated gadolinium oxide (Gd2O3).Both the light absorption co-efficient and refractive index change upon exposure to chemical vapours of volatile organic compounds (VOCs) such as ammonia (NH3), ethanol (CH3CH2OH), and methanol (CH3OH). The spectral characteristics of the sensor were studied for different concentrations ranging from 0-500 ppm. These changes induced the optical intensity modulation of the transmitted optical signal. During interaction between the sensing material and VOCs, the output intensity is taken into account to detect the toxic VOCs present in the environment. This was systematically investigated by X-ray diffractometer (XRD) and SEM. The XRD analysis indicated that the calcinated Gd2O3 was formed in cubic structure with the crystallite size of 13 nm. The Gd2O3 nanorods with thickness ranging from 80 to 120 nm were confirmed from SEM. The ammonia gas response of the Gd2O3 sensor is presented. A model is proposed for understanding the spectral intensity variations.

The unique features of glycolytic pathways in Archaea.

OpenAIRE

Verhees, Corné H; Kengen, Servé W M; Tuininga, Judith E; Schut, Gerrit J; Adams, Michael W W; De Vos, Willem M; Van Der Oost, John

2003-01-01

An early divergence in evolution has resulted in two prokaryotic domains, the Bacteria and the Archaea. Whereas the central metabolic routes of bacteria and eukaryotes are generally well-conserved, variant pathways have developed in Archaea involving several novel enzymes with a distinct control. A spectacular example of convergent evolution concerns the glucose-degrading pathways of saccharolytic archaea. The identification, characterization and comparison of the glycolytic enzymes of a vari...

Molecular biology of hyperthermophilic Archaea.

Science.gov (United States)

van der Oost, J; Ciaramella, M; Moracci, M; Pisani, F M; Rossi, M; de Vos, W M

1998-01-01

The sequences of a number of archaeal genomes have recently been completed, and many more are expected shortly. Consequently, the research of Archaea in general and hyperthermophiles in particular has entered a new phase, with many exciting discoveries to be expected. The wealth of sequence information has already led, and will continue to lead to the identification of many enzymes with unique properties, some of which have potential for industrial applications. Subsequent functional genomics will help reveal fundamental matters such as details concerning the genetic, biochemical and physiological adaptation of extremophiles, and hence give insight into their genomic evolution, polypeptide structure-function relations, and metabolic regulation. In order to optimally exploit many unique features that are now emerging, the development of genetic systems for hyperthermophilic Archaea is an absolute requirement. Such systems would allow the application of this class of Archaea as so-called "cell factories": (i) expression of certain archaeal enzymes for which no suitable conventional (mesophilic bacterial or eukaryal) systems are available, (ii) selection for thermostable variants of potentially interesting enzymes from mesophilic origin, and (iii) the development of in vivo production systems by metabolic engineering. An overview is given of recent insight in the molecular biology of hyperthermophilic Archaea, as well as of a number of promising developments that should result in the generation of suitable genetic systems in the near future.

Shifts among Eukaryota, Bacteria, and Archaea define the vertical organization of a lake sediment.

Science.gov (United States)

Wurzbacher, Christian; Fuchs, Andrea; Attermeyer, Katrin; Frindte, Katharina; Grossart, Hans-Peter; Hupfer, Michael; Casper, Peter; Monaghan, Michael T

2017-04-08

Lake sediments harbor diverse microbial communities that cycle carbon and nutrients while being constantly colonized and potentially buried by organic matter sinking from the water column. The interaction of activity and burial remained largely unexplored in aquatic sediments. We aimed to relate taxonomic composition to sediment biogeochemical parameters, test whether community turnover with depth resulted from taxonomic replacement or from richness effects, and to provide a basic model for the vertical community structure in sediments. We analyzed four replicate sediment cores taken from 30-m depth in oligo-mesotrophic Lake Stechlin in northern Germany. Each 30-cm core spanned ca. 170 years of sediment accumulation according to 137 Cs dating and was sectioned into layers 1-4 cm thick. We examined a full suite of biogeochemical parameters and used DNA metabarcoding to examine community composition of microbial Archaea, Bacteria, and Eukaryota. Community β-diversity indicated nearly complete turnover within the uppermost 30 cm. We observed a pronounced shift from Eukaryota- and Bacteria-dominated upper layers (14 cm) dominated by enigmatic Archaea that typically occur in deep-sea sediments. Taxonomic replacement was the prevalent mechanism in structuring the community composition and was linked to parameters indicative of microbial activity (e.g., CO 2 and CH 4 concentration, bacterial protein production). Richness loss played a lesser role but was linked to conservative parameters (e.g., C, N, P) indicative of past conditions. By including all three domains, we were able to directly link the exponential decay of eukaryotes with the active sediment microbial community. The dominance of Archaea in deeper layers confirms earlier findings from marine systems and establishes freshwater sediments as a potential low-energy environment, similar to deep sea sediments. We propose a general model of sediment structure and function based on microbial characteristics and

Influence of oxygen partial pressure and salinity on the community composition of ammonia-oxidizing bacteria in the Schelde estuary

NARCIS (Netherlands)

Bollmann, A.; Laanbroek, H.J.

2002-01-01

The influence of environmental factors on the community structure of ammonia-oxidizing bacteria (AOB) was investigated in the Schelde estuary. Simultaneously with the increase of oxygen and salinity, a shift of the dominant AOB was observed. Molecular analysis based on 16S rRNA genes showed that the

Proteomic properties reveal phyloecological clusters of Archaea.

Directory of Open Access Journals (Sweden)

Nela Nikolic

Full Text Available In this study, we propose a novel way to describe the variety of environmental adaptations of Archaea. We have clustered 57 Archaea by using a non-redundant set of proteomic features, and verified that the clusters correspond to environmental adaptations to the archaeal habitats. The first cluster consists dominantly of hyperthermophiles and hyperthermoacidophilic aerobes. The second cluster joins together halophilic and extremely halophilic Archaea, while the third cluster contains mesophilic (mostly methanogenic Archaea together with thermoacidophiles. The non-redundant subset of proteomic features was found to consist of five features: the ratio of charged residues to uncharged, average protein size, normalized frequency of beta-sheet, normalized frequency of extended structure and number of hydrogen bond donors. We propose this clustering to be termed phyloecological clustering. This approach could give additional insights into relationships among archaeal species that may be hidden by sole phylogenetic analysis.

[Abundances of ammonia-oxidizing archaeal accA and amoA genes in response to NO2 - and NO3 - of hot springs in Yunnan province].

Science.gov (United States)

Song, Zhaoqi; Wang, Li; Zhou, Enmin; Wang, Fengping; Xiao, Xiang; Zhang, Chuanlun; Li, Wenjun

2014-12-04

Yunnan hot springs have highly diverseammonia-oxidizing archaea (AOA), which are autotrophic and can fix CO2 using the 3-hydroxypropionate/ 4-hydroxybutyrate (HP/HD) pathway. In this study, we investigated the abundances of prokaryotic 16S rRNA gene and archaeal accA and amoA genes in the sediments of hot springs of Yunnan Province, and analysed the correlations between the above gene abundances and environmental factors. We selected the sediments of twenty representative hot springs, and detected the gene abundances by quantitative polymerase chain reaction (qPCR). The principal component analysis (PCA) and the Mantel test in the R software package were performed for the correlations of gene abundance and environmental variables. The bacterial and archaeal 16S rRNA gene abundances were from 6.6 x 10(7) to 4.19 x 10(11) and from 1.27 x 10(6) to 1.51 x 10(11) copies/g sediment, respectively; Archaeal accA and amoA genes were from 8.89 x 10(3) to 6.49 x 10(5) and from 7.64 x 10(3) to 4.36 x 10(5) copies/g sediment, respectively. The results of mantel test showed that accA gene was significantly (R = 0.98, P < 0.001) correlated with amoA gene; Both of them also were correlated significantly with NO2- and NO3 -, but not with pH. The abundances of bacterial and archaeal 16S rRNA genes and the ratio between them varied significantly among Yunnan hot springs. The archaealaccA and amoA genes showed significant correlation with each other, validating our previous finding that AOA in terrestrial hot springs might acquire energy from ammonia oxidation coupled with CO2 fixation using the 3-hydroxypropionate/4-hydroxybutyrate pathway.

Simultaneous determination of ammonia, dimethylamine, trimethylamine and trimethylamine-N-oxide in fish extracts by capillary electrophoresis with indirect UV-detection

DEFF Research Database (Denmark)

Timm Heinrich, Maike; Jørgensen, Bo

2002-01-01

A capillary electrophoretic method with indirect UV detection is described for simultaneous determination of ammonia, dimethylamine (DMA), trimethylamine (TMA) and trimethylamine-N- oxide (TMAO) in aqueous extracts of fish, A buffer consisting of 4 mM formic acid, 5 mM copper(II)sulfate and 3 m......M. The detection limit for ammonia, DMA, TMA, and TMAO was less than 0.04 mM, corresponding to 2 mg nitrogen per 100 g fish. As an extra benefit, the method also provided a quantitative determination of potassium, sodium, calcium and magnesium ions. (C) 2002 Elsevier Science Ltd. All rights reserved....

Ammonia synthesis over multi-promoted iron catalysts obtained by high-energy ball-milling

DEFF Research Database (Denmark)

Jacobsen, C.J.H.; Jiang, Jianzhong; Mørup, Steen

1999-01-01

The feasibility of producing ammonia synthesis catalysts from high-energy ball-milling of a simple mixture of the constituent oxides has been investigated. The effect of ball-milling the fused oxidic precursor of the industrial KM1 ammonia synthesis catalyst has also been studied. The results show...

Simultaneous stripping recovery of ammonia-nitrogen and precipitation of manganese from electrolytic manganese residue by air under calcium oxide assist.

Science.gov (United States)

Chen, Hongliang; Liu, Renlong; Shu, Jiancheng; Li, Wensheng

2015-01-01

Leaching tests of electrolytic manganese residue (EMR) indicated that high contents of soluble manganese and ammonia-nitrogen posed a high environmental risk. This work reports the results of simultaneous stripping recovery of ammonia-nitrogen and precipitation of manganese by air under calcium oxide assist. The ammonia-nitrogen stripping rate increased with the dosage of CaO, the air flow rate and the temperature of EMR slurry. Stripped ammonia-nitrogen was absorbed by a solution of sulfuric acid and formed soluble (NH4)2SO4 and (NH4)3H(SO4)3. The major parameters that effected soluble manganese precipitation were the dosage of added CaO and the slurry temperature. Considering these two aspects, the efficient operation conditions should be conducted with 8 wt.% added CaO, 60°C, 800 mL min(-1) air flow rate and 60-min reaction time. Under these conditions 99.99% of the soluble manganese was precipitated as Mn3O4, which was confirmed by XRD and SEM-EDS analyses. In addition, the stripping rate of ammonia-nitrogen was 99.73%. Leaching tests showed the leached toxic substances concentrations of the treated EMR met the integrated wastewater discharge standard of China (GB8978-1996).

Novel metabolic pathways in Archaea.

Science.gov (United States)

Sato, Takaaki; Atomi, Haruyuki

2011-06-01

The Archaea harbor many metabolic pathways that differ to previously recognized classical pathways. Glycolysis is carried out by modified versions of the Embden-Meyerhof and Entner-Doudoroff pathways. Thermophilic archaea have recently been found to harbor a bi-functional fructose-1,6-bisphosphate aldolase/phosphatase for gluconeogenesis. A number of novel pentose-degrading pathways have also been recently identified. In terms of anabolic metabolism, a pathway for acetate assimilation, the methylaspartate cycle, and two CO2-fixing pathways, the 3-hydroxypropionate/4-hydroxybutyrate cycle and the dicarboxylate/4-hydroxybutyrate cycle, have been elucidated. As for biosynthetic pathways, recent studies have clarified the enzymes responsible for several steps involved in the biosynthesis of inositol phospholipids, polyamine, coenzyme A, flavin adeninedinucleotide and heme. By examining the presence/absence of homologs of these enzymes on genome sequences, we have found that the majority of these enzymes and pathways are specific to the Archaea. Copyright © 2011 Elsevier Ltd. All rights reserved.

Comammox Nitrospira are abundant ammonia oxidizers in diverse groundwater‐fed rapid sand filter communities

DEFF Research Database (Denmark)

Fowler, Susan Jane; Palomo, Alejandro; Dechesne, Arnaud

2018-01-01

quantification and diversity assessement of both comammox Nitrospira clades. The primers cover a wide range of comammox diversity, spanning all available high quality sequences. We applied these primers to 12 groundwater‐fed rapid sand filters, and found comammox Nitrospira to be abundant in all filters. Clade B...

Spatiotemporal variability in archaeal communities of tropical coastal waters

Digital Repository Service at National Institute of Oceanography (India)

Singh, S.K.

properties on SST biases and the South Asian summer monsoon in a coupled GCM. Clim Dyn 39:811–826 Urakawa H, Martens-Habbena W, Stahl DA (2010) High abundance of ammonia-oxidizing archaea in coastal waters, determined using a modified DNA extraction method...- ments suggests that archaea play a major role in the global nitrification process (Francis et al. 2005; Prosser and Nicol 2008; Wuchter et al. 2006). Denaturing gradient gel electrophoresis (DGGE) is among the reliable techniques for microbial...

Detoxification of ammonia in mouse cortical GABAergic cell cultures increases neuronal oxidative metabolism and reveals an emerging role for release of glucose-derived alanine.

Science.gov (United States)

Leke, Renata; Bak, Lasse K; Anker, Malene; Melø, Torun M; Sørensen, Michael; Keiding, Susanne; Vilstrup, Hendrik; Ott, Peter; Portela, Luis V; Sonnewald, Ursula; Schousboe, Arne; Waagepetersen, Helle S

2011-04-01

Cerebral hyperammonemia is believed to play a pivotal role in the development of hepatic encephalopathy (HE), a debilitating condition arising due to acute or chronic liver disease. In the brain, ammonia is thought to be detoxified via the activity of glutamine synthetase, an astrocytic enzyme. Moreover, it has been suggested that cerebral tricarboxylic acid (TCA) cycle metabolism is inhibited and glycolysis enhanced during hyperammonemia. The aim of this study was to characterize the ammonia-detoxifying mechanisms as well as the effects of ammonia on energy-generating metabolic pathways in a mouse neuronal-astrocytic co-culture model of the GABAergic system. We found that 5 mM ammonium chloride affected energy metabolism by increasing the neuronal TCA cycle activity and switching the astrocytic TCA cycle toward synthesis of substrate for glutamine synthesis. Furthermore, ammonia exposure enhanced the synthesis and release of alanine. Collectively, our results demonstrate that (1) formation of glutamine is seminal for detoxification of ammonia; (2) neuronal oxidative metabolism is increased in the presence of ammonia; and (3) synthesis and release of alanine is likely to be important for ammonia detoxification as a supplement to formation of glutamine.

Biogeochemical controls and isotopic signatures of nitrous oxide production by a marine ammonia-oxidizing bacterium

Directory of Open Access Journals (Sweden)

C. H. Frame

2010-09-01

Full Text Available Nitrous oxide (N₂O is a trace gas that contributes to the greenhouse effect and stratospheric ozone depletion. The N₂O yield from nitrification (moles N₂O-N produced per mole ammonium-N consumed has been used to estimate marine N₂O production rates from measured nitrification rates and global estimates of oceanic export production. However, the N₂O yield from nitrification is not constant. Previous culture-based measurements indicate that N₂O yield increases as oxygen (O₂ concentration decreases and as nitrite (NO₂⁻ concentration increases. Here, we have measured yields of N₂O from cultures of the marine β-proteobacterium Nitrosomonas marina C-113a as they grew on low-ammonium (50 μM media. These yields, which were typically between 4 × 10⁻⁴ and 7 × 10⁻⁴ for cultures with cell densities between 2 × 10² and 2.1 × 10⁴ cells ml⁻¹, were lower than previous reports for ammonia-oxidizing bacteria. The observed impact of O₂ concentration on yield was also smaller than previously reported under all conditions except at high starting cell densities (1.5 × 10⁶ cells ml⁻¹, where 160-fold higher yields were observed at 0.5% O₂ (5.1 μM dissolved O₂ compared with 20% O₂ (203 μM dissolved O₂. At lower cell densities (2 × 10² and 2.1 × 10⁴ cells ml⁻¹, cultures grown under 0.5% O₂ had yields that were only 1.25- to 1.73-fold higher than cultures grown under 20% O₂. Thus, previously reported many-fold increases in N₂O yield with dropping O₂ could be reproduced only at cell densities that far exceeded those of ammonia oxidizers in the ocean. The presence of excess NO₂⁻ (up to 1 mM in the growth

Nitrite-Oxidizing Bacteria Community Composition and Diversity Are Influenced by Fertilizer Regimes, but Are Independent of the Soil Aggregate in Acidic Subtropical Red Soil.

Science.gov (United States)

Han, Shun; Li, Xiang; Luo, Xuesong; Wen, Shilin; Chen, Wenli; Huang, Qiaoyun

2018-01-01

Nitrification is the two-step aerobic oxidation of ammonia to nitrate via nitrite in the nitrogen-cycle on earth. However, very limited information is available on how fertilizer regimes affect the distribution of nitrite oxidizers, which are involved in the second step of nitrification, across aggregate size classes in soil. In this study, the community compositions of nitrite oxidizers ( Nitrobacter and Nitrospira ) were characterized from a red soil amended with four types of fertilizer regimes over a 26-year fertilization experiment, including control without fertilizer (CK), swine manure (M), chemical fertilization (NPK), and chemical/organic combined fertilization (MNPK). Our results showed that the addition of M and NPK significantly decreased Nitrobacter Shannon and Chao1 index, while M and MNPK remarkably increased Nitrospira Shannon and Chao1 index, and NPK considerably decreased Nitrospira Shannon and Chao1 index, with the greatest diversity achieved in soils amended with MNPK. However, the soil aggregate fractions had no impact on that alpha-diversity of Nitrobacter and Nitrospira under the fertilizer treatment. Soil carbon, nitrogen and phosphorus in the soil had a significant correlation with Nitrospira Shannon and Chao1 diversity index, while total potassium only had a significant correlation with Nitrospira Shannon diversity index. However, all of them had no significant correlation with Nitrobacter Shannon and Chao1 diversity index. The resistance indices for alpha-diversity indexes (Shannon and Chao1) of Nitrobacter were higher than those of Nitrospira in response to the fertilization regimes. Manure fertilizer is important in enhancing the Nitrospira Shannon and Chao1 index resistance. Principal co-ordinate analysis revealed that Nitrobacter - and Nitrospira -like NOB communities under four fertilizer regimes were differentiated from each other, but soil aggregate fractions had less effect on the nitrite oxidizers community. Redundancy analysis

Determination of surface coverage of catalysts : temperature programmed experiments on platinum and iridium sponge catalysts after low temperature ammonia oxidation

NARCIS (Netherlands)

van den Broek, A.C.M.; Grondelle, van J.; Santen, van R.A.

1999-01-01

The activity of iridium and platinum sponge catalysts was studied in the low temperature gas phase oxidation of ammonia with oxygen. Under the reaction conditions used, iridium was found to be more active and more selective to nitrogen than platinum. Furthermore it was established from activity

?Altiarchaeales?: Uncultivated Archaea from the Subsurface

OpenAIRE

Probst, Alexander J.; Moissl-Eichinger, Christine

2015-01-01

Due to the limited cultivability of the vast majority of microorganisms, researchers have applied environmental genomics and other state-of-the-art technologies to gain insights into the biology of uncultivated Archaea and bacteria in their natural biotope. In this review, we summarize the scientific findings on a recently proposed order-level lineage of uncultivated Archaea called Altiarchaeales, which includes “Candidatus Altiarchaeum hamiconexum” as the most well-described representative. ...

Diversity in electrochemical oxidation of dihydroxybenzenes in the ...

Indian Academy of Sciences (India)

Abstract. Electrochemical oxidation of some catechol derivatives (1a–e) have been studied in water/ acetonitrile solution containing 1-methylindole (3) as a nucleophile, using cyclic voltammetry and controlled- potential coulometry. An interesting diversity in the mechanisms has been observed in electrochemical oxidation ...

Dynamics of nitrification and denitrification in root- oxygenated sediments and adaptation of ammonia-oxidizing bacteria to low-oxygen or anoxic habitats

NARCIS (Netherlands)

Bodelier, P.L.E.; Libochant, J.A.; Blom, C.W.P.M.; Laanbroek, H.J.

1996-01-01

Oxygen-releasing plants may provide aerobic niches in anoxic sediments and soils for ammonia-oxidizing bacteria, The oxygen- releasing, aerenchymatous emergent macrophyte Glycerin maxima had a strong positive effect on numbers and activities of the nitrifying bacteria in its root zone in spring and

Dynamics of nitrification and denitrification in root- oxygenated sediments and adaptation of ammonia-oxidizing bacteria to low-oxygen or anoxic habitats

NARCIS (Netherlands)

Bodelier, P.L.E.; Libochant, J.A.; Blom, C.W.P.M.; Laanbroek, H.J.

1996-01-01

Oxygen-releasing plants may provide aerobic niches in anoxic sediments and soils for ammonia-oxidizing bacteria. The oxygen-releasing, aerenchymatous emergent macrophyte Glyceria maxima had a strong positive effect on numbers and activities of the nitrifying bacteria in its root zone in spring and

Isoprenoid biosynthesis in Archaea - Biochemical and evolutionary implications

NARCIS (Netherlands)

Matsumi, Rie; Atomi, Haruyuki; Driessen, Arnold J. M.; van der Oost, John

Isoprenoids are indispensable for all types of cellular life in the Archaea, Bacteria, and Eucarya. These membrane-associated molecules are involved in a wide variety of vital biological functions, ranging from compartmentalization and stability, to protection and energy-transduction. In Archaea,

Plant Community and Nitrogen Deposition as Drivers of Alpha and Beta Diversities of Prokaryotes in Reconstructed Oil Sand Soils and Natural Boreal Forest Soils.

Science.gov (United States)

Masse, Jacynthe; Prescott, Cindy E; Renaut, Sébastien; Terrat, Yves; Grayston, Sue J

2017-05-01

The Athabasca oil sand deposit is one of the largest single oil deposits in the world. Following surface mining, companies are required to restore soil-like profiles that can support the previous land capabilities. The objective of this study was to assess whether the soil prokaryotic alpha diversity (α-diversity) and β-diversity in oil sand soils reconstructed 20 to 30 years previously and planted to one of three vegetation types (coniferous or deciduous trees and grassland) were similar to those found in natural boreal forest soils subject to wildfire disturbance. Prokaryotic α-diversity and β-diversity were assessed using massively parallel sequencing of 16S rRNA genes. The β-diversity, but not the α-diversity, differed between reconstructed and natural soils. Bacteria associated with an oligotrophic lifestyle were more abundant in natural forest soils, whereas bacteria associated with a copiotrophic lifestyle were more abundant in reconstructed soils. Ammonia-oxidizing archaea were most abundant in reconstructed soils planted with grasses. Plant species were the main factor influencing α-diversity in natural and in reconstructed soils. Nitrogen deposition, pH, and plant species were the main factors influencing the β-diversity of the prokaryotic communities in natural and reconstructed soils. The results highlight the importance of nitrogen deposition and aboveground-belowground relationships in shaping soil microbial communities in natural and reconstructed soils. IMPORTANCE Covering over 800 km 2 , land disturbed by the exploitation of the oil sands in Canada has to be restored. Here, we take advantage of the proximity between these reconstructed ecosystems and the boreal forest surrounding the oil sand mining area to study soil microbial community structure and processes in both natural and nonnatural environments. By identifying key characteristics shaping the structure of soil microbial communities, this study improved our understanding of how

Chemical pathways for the formation of ammonia in Hanford wastes

International Nuclear Information System (INIS)

Stock, L.M.; Pederson, L.R.

1997-12-01

This report reviews chemical reactions leading to the formation of ammonia in Hanford wastes. The general features of the chemistry of the organic compounds in the Hanford wastes are briefly outlined. The radiolytic and thermal free radical reactions that are responsible for the initiation and propagation of the oxidative degradation reactions of the nitrogen-containing complexants, trisodium HEDTA and tetrasodium EDTA, are outlined. In addition, the roles played by three different ionic reaction pathways for the oxidation of the same compounds and their degradation products are described as a prelude to the discussion of the formation of ammonia. The reaction pathways postulated for its formation are based on tank observations, laboratory studies with simulated and actual wastes, and the review of the scientific literature. Ammonia derives from the reduction of nitrite ion (most important), from the conversion of organic nitrogen in the complexants and their degradation products, and from radiolytic reactions of nitrous oxide and nitrogen (least important)

Chemical pathways for the formation of ammonia in Hanford wastes

Energy Technology Data Exchange (ETDEWEB)

Stock, L.M.; Pederson, L.R.

1997-12-01

This report reviews chemical reactions leading to the formation of ammonia in Hanford wastes. The general features of the chemistry of the organic compounds in the Hanford wastes are briefly outlined. The radiolytic and thermal free radical reactions that are responsible for the initiation and propagation of the oxidative degradation reactions of the nitrogen-containing complexants, trisodium HEDTA and tetrasodium EDTA, are outlined. In addition, the roles played by three different ionic reaction pathways for the oxidation of the same compounds and their degradation products are described as a prelude to the discussion of the formation of ammonia. The reaction pathways postulated for its formation are based on tank observations, laboratory studies with simulated and actual wastes, and the review of the scientific literature. Ammonia derives from the reduction of nitrite ion (most important), from the conversion of organic nitrogen in the complexants and their degradation products, and from radiolytic reactions of nitrous oxide and nitrogen (least important).

Geoarchaeota: a new candidate phylum in the Archaea from high-temperature acidic iron mats in Yellowstone National Park

Energy Technology Data Exchange (ETDEWEB)

Kozubal, Mark; Romine, Margaret F.; Jennings, Ryan; Jay, Z.; Tringe, Susannah G.; Rusch, Douglas B.; Beam, Jake; McCue, Lee Ann; Inskeep, William P.

2013-03-01

Geothermal systems in Yellowstone National Park (YNP) provide an outstanding opportunity to understand the origin and evolution of metabolic processes necessary for life in extreme environments including low pH, high temperature, low oxygen and elevated concentrations of reduced iron. Previous phylogenetic studies of acidic ferric iron mats from YNP have revealed considerable diversity of uncultivated and undescribed archaea. The goal of this study was to obtain replicate de novo genome assemblies for a dominant archaeal population inhabiting acidic iron oxide mats in YNP. Detailed analysis of conserved ribosomal and informational processing genes indicate that the replicate assemblies represent a new phylum-level lineage referred to here as 'novel archaeal group 1 (NAG1)'. The NAG1 organisms contain pathways necessary for the catabolism of peptides and complex carbohydrates as well as a bacterial-like Form I CO dehydrogenase complex likely used for energy conservation. Moreover, this novel population contains genes involved in metabolism of oxygen including a Type A heme copper oxidase, a bd-type terminal oxidase and a putative oxygen sensing protoglobin. NAG1 has a variety of unique bacterial-like cofactor biosynthesis and transport genes and a Type3-like CRISPR system. Discovery of NAG1 is critical to our understanding of microbial community structure and function in extant thermophilic iron mats of YNP, and will provide insight regarding the evolution of Archaea in early Earth environments that may have important analogues active in YNP today.

Dramatic loss of comammox Nitrospira associated with long-term nitrite feeding

DEFF Research Database (Denmark)

Kinnunen, Marta; Palomo, Alejandro; Dechesne, Arnaud

Until recently, nitrification was thought to be a strict two-step process where ammonia was first oxidized to nitrite by ammonia-oxidizing bacteria and/or archaea, and subsequently to nitrate by nitrite oxidizing bacteria (NOB). Recent studies in NOB metabolism, however, have revealed that certain......, with nitrite as the main energy source. Community assembly was monitored on well-established biofilms formed on the grains of rapid sand filter (RSF) for drinking water production. RSF sand was placed in laboratory scale column bioreactors and subjected to continuous feeding of tap water spiked with NO2- (1 mg...... sequences (100% similarity to uncultured Nitrospira sp. clone KC836101 (Pester et al., 2014)). These observations indicate different behavior of Nitrospira in the absence of ammonia and point to a possible competitive advantage of canonical Nitrospira in environments where nitrite is the sole nitrogen...

Nitrous oxide emission from the agriculture in the Netherlands. Outline of effects of manure and ammonia measures

International Nuclear Information System (INIS)

Kros, J.; De Vries, W.; Oenema, O.; Velthof, G.; Kuikman, P.J.; Van Hove, B.

2004-01-01

By means of the model INITIATOR an integral outline was made of the effects of several measures within the framework of the manure and ammonia policy focusing on nitrous oxide emission. The results are compared with the IPCC method. The model INITIATOR is a mechanistic model by means of which the carbon cycle in the Netherlands can be differentiated on a regional scale as a function of land use, type of soil and hydrology [nl

Activity, Microenvironments, and Community Structure of Aerobic and Anaerobic Ammonium Oxidizing Prokaryotes in Estuarine Sediment (Randers Fjord, DK)

DEFF Research Database (Denmark)

Schramm, Andreas; Revsbech, Niels Peter; Dalsgaard, Tage

2006-01-01

ACTIVITY, MICROENVIRONMENTS, AND COMMUNITY STRUCTURE OF AEROBIC AND ANAEROBIC AMMONIUM OXIDIZING PROKARYOTES IN ESTUARINE SEDIMENT (RANDERS FJORD, DK) A. Schramm 1, N.P. Revsbech 1, T. Dalsgaard 2, E. Piña-Ochoa 3, J. de la Torré 4, D.A. Stahl 4, N. Risgaard-Petersen 2 1 Department of Biological...... conversion of ammonium with nitrite to N2, is increasingly recognized as link in the aquatic nitrogen cycle. However, factors regulating the occurrence and activity of anammox bacteria are still poorly understood. Besides the influence of abiotic factors, anammox might be controlled by either aerobic ammonia...... oxidizing bacteria and archaea (AOB and AOA) or nitrate-reducing/denitrifying bacteria via their supply of nitrite. Along the Randers Fjord estuary (Denmark), gradients of salinity, nutrients, and organic loading can be observed, and anammox has been detected previously at some sites. The aim of this study...

Updated clusters of orthologous genes for Archaea: a complex ancestor of the Archaea and the byways of horizontal gene transfer

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Wolf Yuri I

2012-12-01

Full Text Available Abstract Background Collections of Clusters of Orthologous Genes (COGs provide indispensable tools for comparative genomic analysis, evolutionary reconstruction and functional annotation of new genomes. Initially, COGs were made for all complete genomes of cellular life forms that were available at the time. However, with the accumulation of thousands of complete genomes, construction of a comprehensive COG set has become extremely computationally demanding and prone to error propagation, necessitating the switch to taxon-specific COG collections. Previously, we reported the collection of COGs for 41 genomes of Archaea (arCOGs. Here we present a major update of the arCOGs and describe evolutionary reconstructions to reveal general trends in the evolution of Archaea. Results The updated version of the arCOG database incorporates 91% of the pangenome of 120 archaea (251,032 protein-coding genes altogether into 10,335 arCOGs. Using this new set of arCOGs, we performed maximum likelihood reconstruction of the genome content of archaeal ancestral forms and gene gain and loss events in archaeal evolution. This reconstruction shows that the last Common Ancestor of the extant Archaea was an organism of greater complexity than most of the extant archaea, probably with over 2,500 protein-coding genes. The subsequent evolution of almost all archaeal lineages was apparently dominated by gene loss resulting in genome streamlining. Overall, in the evolution of Archaea as well as a representative set of bacteria that was similarly analyzed for comparison, gene losses are estimated to outnumber gene gains at least 4 to 1. Analysis of specific patterns of gene gain in Archaea shows that, although some groups, in particular Halobacteria, acquire substantially more genes than others, on the whole, gene exchange between major groups of Archaea appears to be largely random, with no major ‘highways’ of horizontal gene transfer. Conclusions The updated collection

A review of the microbiology of the Rehai geothermal field in Tengchong, Yunnan Province, China

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Brian P. Hedlund

2012-05-01

Full Text Available The Rehai Geothermal Field, located in Tengchong County, in central-western Yunnan Province, is the largest and most intensively studied geothermal field in China. A wide physicochemical diversity of springs (ambient to ∼97 °C; pH from ≤1.8 to ≥9.3 provides a multitude of niches for extremophilic microorganisms. A variety of studies have focused on the cultivation, identification, basic physiology, taxonomy, and biotechnological potential of thermophilic microorganisms from Rehai. Thermophilic bacteria isolated from Rehai belong to the phyla Firmicutes and Deinococcus-Thermus. Firmicutes include neutrophilic or alkaliphilic Anoxybacillus, Bacillus, Caldalkalibacillus, Caldanaerobacter, Laceyella, and Geobacillus, as well as thermoacidophilic Alicyclobacillus and Sulfobacillus. Isolates from the Deinococcus-Thermus phylum include several Meiothermus and Thermus species. Many of these bacteria synthesize thermostable polymer-degrading enzymes that may be useful for biotechnology. The thermoacidophilic archaea Acidianus, Metallosphaera, and Sulfolobus have also been isolated and studied. A few studies have reported the isolation of thermophilic viruses belonging to Siphoviridae (TTSP4 and TTSP10 and Fuselloviridae (STSV1 infecting Thermus spp. and Sulfolobus spp., respectively. More recently, cultivation-independent studies using 16S rRNA gene sequences, shotgun metagenomics, or “functional gene” sequences have revealed a much broader diversity of microorganisms than represented in culture. Studies of the gene and mRNA encoding the large subunit of the ammonia monooxygenase (amoA of ammonia-oxidizing Archaea (AOA and the tetraether lipid crenarchaeol, a potential biomarker for AOA, suggest a wide diversity, but possibly low abundance, of thermophilic AOA in Rehai. Finally, we introduce the Tengchong Partnerships in International Research and Education (PIRE project, an international collaboration between Chinese and U.S. scientists with

High-throughput analysis of ammonia oxidiser community composition via a novel, amoA-based functional gene array.

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Guy C J Abell

Full Text Available Advances in microbial ecology research are more often than not limited by the capabilities of available methodologies. Aerobic autotrophic nitrification is one of the most important and well studied microbiological processes in terrestrial and aquatic ecosystems. We have developed and validated a microbial diagnostic microarray based on the ammonia-monooxygenase subunit A (amoA gene, enabling the in-depth analysis of the community structure of bacterial and archaeal ammonia oxidisers. The amoA microarray has been successfully applied to analyse nitrifier diversity in marine, estuarine, soil and wastewater treatment plant environments. The microarray has moderate costs for labour and consumables and enables the analysis of hundreds of environmental DNA or RNA samples per week per person. The array has been thoroughly validated with a range of individual and complex targets (amoA clones and environmental samples, respectively, combined with parallel analysis using traditional sequencing methods. The moderate cost and high throughput of the microarray makes it possible to adequately address broader questions of the ecology of microbial ammonia oxidation requiring high sample numbers and high resolution of the community composition.

Fluctuations in ammonia oxidizing communities across agricultural soils are driven by soil structure and pH

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Michele C ePereira e Silva

2012-03-01

Full Text Available The milieu in soil in which microorganisms dwell is never constant. Conditions such as temperature, water availability, pH and nutrients frequently change, impacting the overall functioning of the soil system. To understand the effects of such factors on soil functioning, proxies (indicators of soil function are needed that, in a sensitive manner, reveal normal amplitude of variation. Thus, the so-called normal operating range (NOR of soil can be defined. In this study we determined different components of nitrification by analyzing, in eight agricultural soils, how the community structures and sizes of ammonia oxidizing bacteria and archaea (AOB and AOA, respectively, and their activity, fluctuate over spatial and temporal scales. The results indicated that soil pH and soil type are the main factors that influence the size and structure of the AOA and AOB, as well as their function. The nitrification rates varied between 0.11 ± 0.03 µgN.h-1.gdw-1 and 1.68 ± 0.11 µgN.h-1.gdw-1, being higher in soils with higher clay content (1.09 ± 0.12 µgN.h-1.gdw-1 and lower in soils with lower clay percentages (0.27 ± 0.04 µgN.h-1.gdw-1. Nitrifying activity was driven by soil pH, mostly related to its effect on AOA but not on AOB abundance. Regarding the influence of soil parameters, clay content was the main soil factor shaping the structure of both the AOA and AOB communities. Overall, the potential nitrifying activities were higher and more variable over time in the clayey than in the sandy soils. Whereas the structure of AOB fluctuated more (62.7 ± 2.10% the structure of AOA communities showed lower amplitude of variation (53.65 ± 3.37%. Similar trends were observed for the sizes of these communities. The present work represents a first step towards defining a NOR for soil nitrification. Moreover, the clear effect of soil texture established here suggests that the NOR should be defined in a soil-type-specific manner.

Novel Syntrophic Populations Dominate an Ammonia-Tolerant Methanogenic Microbiome.

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Frank, J A; Arntzen, M Ø; Sun, L; Hagen, L H; McHardy, A C; Horn, S J; Eijsink, V G H; Schnürer, A; Pope, P B

2016-01-01

Biogas reactors operating with protein-rich substrates have high methane potential and industrial value; however, they are highly susceptible to process failure because of the accumulation of ammonia. High ammonia levels cause a decline in acetate-utilizing methanogens and instead promote the conversion of acetate via a two-step mechanism involving syntrophic acetate oxidation (SAO) to H 2 and CO 2 , followed by hydrogenotrophic methanogenesis. Despite the key role of syntrophic acetate-oxidizing bacteria (SAOB), only a few culturable representatives have been characterized. Here we show that the microbiome of a commercial, ammonia-tolerant biogas reactor harbors a deeply branched, uncultured phylotype (unFirm_1) accounting for approximately 5% of the 16S rRNA gene inventory and sharing 88% 16S rRNA gene identity with its closest characterized relative. Reconstructed genome and quantitative metaproteomic analyses imply unFirm_1's metabolic dominance and SAO capabilities, whereby the key enzymes required for acetate oxidation are among the most highly detected in the reactor microbiome. While culturable SAOB were identified in genomic analyses of the reactor, their limited proteomic representation suggests that unFirm_1 plays an important role in channeling acetate toward methane. Notably, unFirm_1-like populations were found in other high-ammonia biogas installations, conjecturing a broader importance for this novel clade of SAOB in anaerobic fermentations. IMPORTANCE The microbial production of methane or "biogas" is an attractive renewable energy technology that can recycle organic waste into biofuel. Biogas reactors operating with protein-rich substrates such as household municipal or agricultural wastes have significant industrial and societal value; however, they are highly unstable and frequently collapse due to the accumulation of ammonia. We report the discovery of a novel uncultured phylotype (unFirm_1) that is highly detectable in metaproteomic data

Comammox in drinking water systems.

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Wang, Yulin; Ma, Liping; Mao, Yanping; Jiang, Xiaotao; Xia, Yu; Yu, Ke; Li, Bing; Zhang, Tong

2017-06-01

The discovery of complete ammonia oxidizer (comammox) has fundamentally upended our perception of the global nitrogen cycle. Here, we reported four metagenome assembled genomes (MAGs) of comammox Nitrospira that were retrieved from metagenome datasets of tap water in Singapore (SG-bin1 and SG-bin2), Hainan province, China (HN-bin3) and Stanford, CA, USA (ST-bin4). Genes of phylogenetically distinct ammonia monooxygenase subunit A (amoA) and hydroxylamine dehydrogenase (hao) were identified in these four MAGs. Phylogenetic analysis based on ribosomal proteins, AmoA, hao and nitrite oxidoreductase (subunits nxrA and nxrB) sequences indicated their close relationships with published comammox Nitrospira. Canonical ammonia-oxidizing microbes (AOM) were also identified in the three tap water samples, ammonia-oxidizing bacteria (AOB) in Singapore's and Stanford's samples and ammonia-oxidizing archaea (AOA) in Hainan's sample. The comammox amoA-like sequences were also detected from some other drinking water systems, and even outnumbered the AOA and AOB amoA-like sequences. The findings of MAGs and the occurrences of AOM in different drinking water systems provided a significant clue that comammox are widely distributed in drinking water systems. Copyright © 2017 Elsevier Ltd. All rights reserved.

Insights into the diversity of eukaryotes in acid mine drainage biofilm communities.

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Baker, Brett J; Tyson, Gene W; Goosherst, Lindsey; Banfield, Jillian F

2009-04-01

Microscopic eukaryotes are known to have important ecosystem functions, but their diversity in most environments remains vastly unexplored. Here we analyzed an 18S rRNA gene library from a subsurface iron- and sulfur-oxidizing microbial community growing in highly acidic (pH morphological characterization. Results revealed that the populations vary significantly with the habitat and no group is ubiquitous. Surprisingly, many of the eukaryotic lineages (with the exception of the APC) are closely related to neutrophiles, suggesting that they recently adapted to this extreme environment. Molecular analyses presented here confirm that the number of eukaryotic species associated with the acid mine drainage (AMD) communities is low. This finding is consistent with previous results showing a limited diversity of archaea, bacteria, and viruses in AMD environments and suggests that the environmental pressures and interplay between the members of these communities limit species diversity at all trophic levels.

A pursuit of lineage-specific and niche-specific proteome features in the world of archaea.

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Roy Chowdhury, Anindya; Dutta, Chitra

2012-06-12

Archaea evoke interest among researchers for two enigmatic characteristics -a combination of bacterial and eukaryotic components in their molecular architectures and an enormous diversity in their life-style and metabolic capabilities. Despite considerable research efforts, lineage- specific/niche-specific molecular features of the whole archaeal world are yet to be fully unveiled. The study offers the first large-scale in silico proteome analysis of all archaeal species of known genome sequences with a special emphasis on methanogenic and sulphur-metabolising archaea. Overall amino acid usage in archaea is dominated by GC-bias. But the environmental factors like oxygen requirement or thermal adaptation seem to play important roles in selection of residues with no GC-bias at the codon level. All methanogens, irrespective of their thermal/salt adaptation, show higher usage of Cys and have relatively acidic proteomes, while the proteomes of sulphur-metabolisers have higher aromaticity and more positive charges. Despite of exhibiting thermophilic life-style, korarchaeota possesses an acidic proteome. Among the distinct trends prevailing in COGs (Cluster of Orthologous Groups of proteins) distribution profiles, crenarchaeal organisms display higher intra-order variations in COGs repertoire, especially in the metabolic ones, as compared to euryarchaea. All methanogens are characterised by a presence of 22 exclusive COGs. Divergences in amino acid usage, aromaticity/charge profiles and COG repertoire among methanogens and sulphur-metabolisers, aerobic and anaerobic archaea or korarchaeota and nanoarchaeota, as elucidated in the present study, point towards the presence of distinct molecular strategies for niche specialization in the archaeal world.

A pursuit of lineage-specific and niche-specific proteome features in the world of archaea

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Roy Chowdhury Anindya

2012-06-01

Full Text Available Abstract Background Archaea evoke interest among researchers for two enigmatic characteristics –a combination of bacterial and eukaryotic components in their molecular architectures and an enormous diversity in their life-style and metabolic capabilities. Despite considerable research efforts, lineage- specific/niche-specific molecular features of the whole archaeal world are yet to be fully unveiled. The study offers the first large-scale in silico proteome analysis of all archaeal species of known genome sequences with a special emphasis on methanogenic and sulphur-metabolising archaea. Results Overall amino acid usage in archaea is dominated by GC-bias. But the environmental factors like oxygen requirement or thermal adaptation seem to play important roles in selection of residues with no GC-bias at the codon level. All methanogens, irrespective of their thermal/salt adaptation, show higher usage of Cys and have relatively acidic proteomes, while the proteomes of sulphur-metabolisers have higher aromaticity and more positive charges. Despite of exhibiting thermophilic life-style, korarchaeota possesses an acidic proteome. Among the distinct trends prevailing in COGs (Cluster of Orthologous Groups of proteins distribution profiles, crenarchaeal organisms display higher intra-order variations in COGs repertoire, especially in the metabolic ones, as compared to euryarchaea. All methanogens are characterised by a presence of 22 exclusive COGs. Conclusions Divergences in amino acid usage, aromaticity/charge profiles and COG repertoire among methanogens and sulphur-metabolisers, aerobic and anaerobic archaea or korarchaeota and nanoarchaeota, as elucidated in the present study, point towards the presence of distinct molecular strategies for niche specialization in the archaeal world.

Backbone and side-chain 1H, 15N and 13C resonance assignments of two Sac10b family members Mvo10b and Mth10bTQQA from archaea.

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Xuan, Jinsong; Yao, Hongwei; Feng, Yingang; Wang, Jinfeng

2017-10-01

The Sac10b family proteins, also named as Alba, are small, basic, nucleic acid-binding proteins widely distributed in archaea. They possess divergent physiological functions such as binding to both DNA and RNA with a high affinity and involving in genomic DNA compaction, RNA transactions and transcriptional regulations. The structures of many Sac10b family proteins from hyperthermophilic archaea have been reported, while those from thermophilic and mesophilic archaea are largely unknown. As was pointed out, the homologous members from thermophilic and mesophilic archaea may have functions different from the hyperthermophilic members. Therefore, comparison of these homologous members can provide biophysical and structural insight into the functional diversity and thermal adaptation mechanism. The present work mainly focused on the NMR study of two Sac10b family members, Mvo10b and Mth10b, from the mesophilic and thermophilic archaea, respectively. To overcome the difficulties caused by the oligomerization and conformation heterogeneity of Mth10b, a M13T/L17Q/I20Q/P56A mutant Mth10b (Mth10bTQQA) was constructed and used together with Mvo10b for multi-dimensional NMR experiments. The resonance assignments of Mvo10b and Mth10bTQQA are reported for further structural determination which is a basis for understanding the functional diversity and their thermal adaption mechanisms.

Diversity and activity of nitrogen fixing archaea and bacteria associated with micro-environments of wetland rice

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Schmidt, Hannes; Woebken, Dagmar

2017-04-01

Wetland rice is one of the world's most important crop plants. The cultivation on waterlogged paddy soils is strongly limited by nitrogen (N), which is typically supplied by industrial fertilizers that are not only costly but also exhibit hazardous effects on the environment. It has been reported that "Biological Nitrogen Fixation" through N2-fixing bacteria and archaea (diazotrophs) can alleviate the N-shortage in rice cultivation, thus carrying out an important ecosystem function. However, our understanding of the diversity and in situ N2 fixation activity of diazotrophs in flooded rice fields is still rudimentary. Moreover, knowledge on the impact of biochemical gradients established by root activity (i.e. exudation, radial oxygen loss) on the functioning of N-fixing microorganisms in paddy soil ecosystems is limited. We aimed at studying underlying processes on biologically relevant scales. Greenhouse studies were performed to identify key factors that control rice-diazotroph association and related N2 fixation activities. Paddy soils of different geographical origin were cultivated with two commercially used genotypes of wetland rice. Samples were separated into bulk soil, rhizosphere soil, rhizoplane, and roots at flowering stage of rice plant development. These samples were subjected to functional assays and various molecular biological techniques in order to analyze the associated diazotroph communities. Based on Illumina amplicon sequencing of nifH genes and transcripts, we show that the diversity and potential activity of diazotroph communities varies according to micro-environments. We will comparatively discuss the influence of (a) the soil microbial "seed bank" and (b) plant genotype in shaping the respective microbiomes and selecting for potentially active diazotrophs. Actual N2 fixation activities of soil-genotype combinations and micro-environments will be shown on the basis of incubation assays using 15N2-containing atmospheres. Areas of potential

Isolation and characterization of two cryptic plasmids in the ammonia-oxidizing bacterium Nitrosomonas sp. strain ENI-11.

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Yamagata, A; Kato, J; Hirota, R; Kuroda, A; Ikeda, T; Takiguchi, N; Ohtake, H

1999-06-01

Two plasmids were discovered in the ammonia-oxidizing bacterium Nitrosomonas sp. strain ENI-11, which was isolated from activated sludge. The plasmids, designated pAYS and pAYL, were relatively small, being approximately 1.9 kb long. They were cryptic plasmids, having no detectable plasmid-linked antibiotic resistance or heavy metal resistance markers. The complete nucleotide sequences of pAYS and pAYL were determined, and their physical maps were constructed. There existed two major open reading frames, ORF1 in pAYS and ORF2 in pAYL, each of which was more than 500 bp long. The predicted product of ORF2 was 28% identical to part of the replication protein of a Bacillus plasmid, pBAA1. However, no significant similarity to any known protein sequences was detected with the predicted product of ORF1. pAYS and pAYL had a highly homologous region, designated HHR, of 262 bp. The overall identity was 98% between the two nucleotide sequences. Interestingly, HHR-homologous sequences were also detected in the genomes of ENI-11 and the plasmidless strain Nitrosomonas europaea IFO14298. Deletion analysis of pAYS and pAYL indicated that HHR, together with either ORF1 or ORF2, was essential for plasmid maintenance in ENI-11. To our knowledge, pAYS and pAYL are the first plasmids found in the ammonia-oxidizing autotrophic bacteria.

Catalytic Hydrolysis of Ammonia Borane by Cobalt Nickel Nanoparticles Supported on Reduced Graphene Oxide for Hydrogen Generation

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Yuwen Yang

2014-01-01

Full Text Available Well dispersed magnetically recyclable bimetallic CoNi nanoparticles (NPs supported on the reduced graphene oxide (RGO were synthesized by one-step in situ coreduction of aqueous solution of cobalt(II chloride, nickel (II chloride, and graphite oxide (GO with ammonia borane (AB as the reducing agent under ambient condition. The CoNi/RGO NPs exhibits excellent catalytic activity with a total turnover frequency (TOF value of 19.54 mol H2 mol catalyst−1 min−1 and a low activation energy value of 39.89 kJ mol−1 at room temperature. Additionally, the RGO supported CoNi NPs exhibit much higher catalytic activity than the monometallic and RGO-free CoNi counterparts. Moreover, the as-prepared catalysts exert satisfying durable stability and magnetically recyclability for the hydrolytic dehydrogenation of AB, which make the practical reusing application of the catalysts more convenient. The usage of the low-cost, easy-getting catalyst to realize the production of hydrogen under mild condition gives more confidence for the application of ammonia borane as a hydrogen storage material. Hence, this general method indicates that AB can be used as both a potential hydrogen storage material and an efficient reducing agent, and can be easily extended to facile preparation of other RGO-based metallic systems.

The Experiment Study of Anaerobic Ammonia Oxidation Start-up by Using the Upflow Double Layer Anaerobic Filter

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YAO Li

2018-02-01

Full Text Available Anammox is an efficient nitrogen removal process, but it is difficult to start-up and operate, and ananammox reactor is the efficient way to resolve this problem. The start-up of anammox reactor by upflow anaerobic filter was studied. Denitrifying sludge, anaerobic sludge, and mixed sludge was inoculated on the packing materials, respectively and an autotrophic denitrification condition was provided by the simulated wastewater influent. Along with the gradual increase of matrix concentration and hydraulic load, the microflora was converted to the anaerobic ammonium oxidation(anammoxreaction. The results showed that the anammox reaction could be started by all the three sludge, and the time of start-up of denitrifying sludge, anaerobic sludge, mixed sludge was 42, 54 days and 45 days, respectively. The best result was that inoculated with denitrifying sludge with 82.2% of the total nitrogen removal rate, which started-up quickly and nitrogen was removed efficiently. Double packing effectively improved the stability of anammox process in the reactor, in which the suitable influent concentration loading for the anammox bacteria was 270 mg·L-1 and 360 mg·L-1 for ammonia nitrogen and nitrite nitrogen, respectively, and the COD concentration could not be more than 150 mg· L-1. Furthermore, there was a coexist-effect for anaerobic ammonia oxidation and methanation in this reactor system.

Archaea: Evolution, Physiology, and Molecular Biology

DEFF Research Database (Denmark)

field, including an account by Carl Woese of his original discovery of the Archaea (until 1990 termed archaebacteria) and the initially mixed reactions of the scientific community. The review chapters and specialized articles address the emerging significance of the Archaea within a broader scientific......Introduced by Crafoord Prize winner Carl Woese, this volume combines reviews of the major developments in archaeal research over the past 10-15 years with more specialized articles dealing with important recent breakthroughs. Drawing on major themes presented at the June 2005 meeting held in Munich...

Microbial diversity in acidic thermal pools in the Uzon Caldera, Kamchatka.

Science.gov (United States)

Mardanov, Andrey V; Gumerov, Vadim M; Beletsky, Alexey V; Ravin, Nikolai V

2018-01-01

Microbial communities of four acidic thermal pools in the Uzon Caldera, Kamchatka, Russia, were studied using amplification and pyrosequencing of 16S rRNA gene fragments. The sites differed in temperature and pH: 1805 (60 °C, pH 3.7), 1810 (90 °C, pH 4.1), 1818 (80 °C, pH 3.5), and 1807 (86 °C, pH 5.6). Archaea of the order Sulfolobales were present among the dominant groups in all four pools. Acidilobales dominated in pool 1818 but were a minor fraction at the higher temperature in pool 1810. Uncultivated Archaea of the Hot Thaumarchaeota-related clade were present in significant quantities in pools 1805 and 1807, but they were not abundant in pools 1810 and 1818, where high temperatures were combined with low pH. Nanoarchaeota were present in all pools, but were more abundant in pools 1810 and 1818. A similar abundance pattern was observed for Halobacteriales. Thermophilic Bacteria were less diverse and were mostly represented by aerobic hydrogen- and sulfur-oxidizers of the phylum Aquificae and sulfur-oxidising Proteobacteria of the genus Acidithiobacillus. Thus we showed that extremely acidic hot pools contain diverse microbial communities comprising different metabolic groups of prokaryotes, including putative lithoautotrophs using energy sources of volcanic origin, and various facultative and obligate heterotrophs.

Ammonia stress under high environmental ammonia induces Hsp70 and Hsp90 in the mud eel, Monopterus cuchia.

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Hangzo, Hnunlalliani; Banerjee, Bodhisattwa; Saha, Shrabani; Saha, Nirmalendu

2017-02-01

The obligatory air-breathing mud eel (Monopterus cuchia) is frequently being challenged with high environmental ammonia (HEA) exposure in its natural habitats. The present study investigated the possible induction of heat shock protein 70 and 90 (hsp70, hsc70, hsp90α and hsp90β) genes and more expression of Hsp70 and Hsp90 proteins under ammonia stress in different tissues of the mud eel after exposure to HEA (50 mM NH 4 Cl) for 14 days. HEA resulted in significant accumulation of toxic ammonia in different body tissues and plasma, which was accompanied with the stimulation of oxidative stress in the mud eel as evidenced by more accumulation of malondialdehyde (MDA) and hydrogen peroxide (H 2 O 2 ) during exposure to HEA. Further, hyper-ammonia stress led to significant increase in the levels of mRNA transcripts for inducible hsp70 and hsp90α genes and also their translated proteins in different tissues probably as a consequence of induction of hsp70 and hsp90α genes in the mud eel. However, hyper-ammonia stress was neither associated with any significant alterations in the levels of mRNA transcripts for constitutive hsc70 and hsp90β genes nor their translated proteins in any of the tissues studied. More abundance of Hsp70 and Hsp90α proteins might be one of the strategies adopted by the mud eel to defend itself from the ammonia-induced cellular damages under ammonia stress. Further, this is the first report of ammonia-induced induction of hsp70 and hsp90α genes under hyper-ammonia stress in any freshwater air-breathing teleost.

Effect of Trichoderma viride biofertilizer on ammonia volatilization from an alkaline soil in Northern China.

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Wang, Xia; Xu, Shengjun; Wu, Shanghua; Feng, Shugeng; Bai, Zhihui; Zhuang, Guoqiang; Zhuang, Xuliang

2018-04-01

Ammonia (NH 3 ) volatilization is one of the primary pathways of nitrogen (N) loss from soils after chemical fertilizer is applied, especially from the alkaline soils in Northern China, which results in lower efficiency for chemical fertilizers. Therefore, we conducted an incubation experiment using an alkaline soil from Tianjin (pH8.37-8.43) to evaluate the suppression effect of Trichoderma viride (T. viride) biofertilizer on NH 3 volatilization, and compared the differences in microbial community structure among all samples. The results showed that viable T. viride biofertilizer (T) decreased NH 3 volatilization by 42.21% compared with conventional fertilizer ((CK), urea), while nonviable T. viride biofertilizer (TS) decreased NH 3 volatilization by 32.42%. NH 3 volatilization was significantly higher in CK and sweet potato starch wastewater (SPSW) treatments during the peak period. T. viride biofertilizer also improved the transfer of ammonium from soil to sweet sorghum. Plant dry weights increased 91.23% and 61.08% for T and TS, respectively, compared to CK. Moreover, T. viride biofertilizer enhanced nitrification by increasing the abundance of ammonium-oxidizing archaea (AOA) and ammonium-oxidizing bacteria (AOB). The results of high-throughput sequencing indicated that the microbial community structure and composition were significantly changed by the application of T. viride biofertilizer. This study demonstrated the immense potential of T. viride biofertilizer in reducing NH 3 volatilization from alkaline soil and simultaneously improving the utilization of fertilizer N by sweet sorghum. Copyright © 2017. Published by Elsevier B.V.

Electrolytic synthesis of ammonia in molten salts under atmospheric pressure.

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Murakami, Tsuyoshi; Nishikiori, Tokujiro; Nohira, Toshiyuki; Ito, Yasuhiko

2003-01-15

Ammonia was successfully synthesized by using a new electrochemical reaction with high current efficiency at atmospheric pressure and at lower temperatures than the Haber-Bosch process. In this method, nitride ion (N3-), which is produced by the reduction from nitrogen gas at the cathode, is anodically oxidized and reacts with hydrogen to produce ammonia at the anode.

Electrospun V2O5 composite fibers: Synthesis, characterization and ammonia sensing properties

International Nuclear Information System (INIS)

Modafferi, V.; Trocino, S.; Donato, A.; Panzera, G.; Neri, G.

2013-01-01

In the present work, vanadium oxide (V 2 O 5 ) fibers have been investigated for monitoring ammonia (NH 3 ) at ppb levels in air. A simple sol gel-based electrospinning process has been applied for the synthesis of vanadium oxide/polyvinyl acetate (PVAc) and vanadium oxide/polyvinylpyrrolidone (PVP) composite fibers. Composite fibers doped with platinum (Pt) have been also prepared. The pure and Pt-doped metal oxide phase has been subsequently obtained by removing the polymer binder at high temperature in air. The samples have been widely studied to characterize their morphological and microstructural properties by X-Ray Diffraction, Fourier Transform InfraRed spectroscopy, X-ray Photoelectron Spectroscopy, and Scanning Electron Microscopy investigations. The application of the produced fibers in highly sensitive ammonia resistive sensors has been demonstrated. The influence of the nature of polymer binder and platinum addition on the sensing performances of the V 2 O 5 fibers has been investigated and discussed.V 2 O 5 fibers produced by using PVP as a polymer binder have shown higher sensitivity toward ammonia at ppb concentrations than fibers obtained with PVAc. Pt-doped samples have shown a lower response compared to un-doped samples. - Highlights: • Synthesis of vanadium oxide composite fibers by electrospinning • Physical and chemical characterization of prepared samples • Investigation of the sensing properties to ppb concentrations of ammonia in air

Evaluating primers for profiling anaerobic ammonia oxidizing bacteria within freshwater environments.

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Puntipar Sonthiphand

Full Text Available Anaerobic ammonia oxidizing (anammox bacteria play an important role in transforming ammonium to nitrogen gas and contribute to fixed nitrogen losses in freshwater environments. Understanding the diversity and abundance of anammox bacteria requires reliable molecular tools, and these are not yet well established for these important Planctomycetes. To help validate PCR primers for the detection of anammox bacteria within freshwater ecosystems, we analyzed representative positive controls and selected samples from Grand River and groundwater sites, both from Ontario, Canada. The objectives of this study were to identify a suitable anammox denaturing gradient gel electrophoresis (DGGE fingerprint method by using GC-clamp modifications to existing primers, and to verify the specificity of anammox-specific primers used for DGGE, cloning and qPCR methods. Six primer combinations were tested from four published primer sets (i.e. A438f/A684r, Amx368f/Amx820r, An7f/An1388r, and Pla46/1392r for both direct and nested PCR amplifications. All PCR products were run subsequently on DGGE gels to compare the resulting patterns. Two anammox-specific primer combinations were also used to generate clone libraries and quantify anammox bacterial 16S rRNA genes with qPCR. The primer set A438f/A684r was highly specific to anammox bacteria, provided reliable DGGE fingerprints and generated a high proportion of anammox-related clones. A second primer set (Amx368f/Amx820r was anammox specific, based on clone library analysis, but PCR products from different candidate species of anammox bacteria resolved poorly using DGGE analysis. Both DGGE and cloning results revealed that Ca. Brocadia and an uncharacterized anammox bacterial cluster represented the majority of anammox bacteria found in Grand River sediment and groundwater samples, respectively. Together, our results demonstrate that although Amx368f/Amx820r was useful for anammox-specific qPCR and clone library

Adsorption of Ammonia on Regenerable Carbon Sorbents

Science.gov (United States)

Wójtowicz, Marek A.; Cosgrove, Jesph E.; Serio, Michael A..; Wilburn, Monique

2015-01-01

Results are presented on the development of reversible sorbents for the combined carbon dioxide, moisture, and trace-contaminant (TC) removal for use in Extravehicular Activities (EVAs), and more specifically in the Primary Life Support System (PLSS). The currently available life support systems use separate units for carbon dioxide, trace contaminants, and moisture control, and the long-term objective is to replace the above three modules with a single one. Data on sorption and desorption of ammonia, which is a major TC of concern, are presented in this paper. The current TC-control technology involves the use of a packed bed of acid-impregnated granular charcoal, which is non-regenerable, and the carbon-based sorbent under development in this project can be regenerated by exposure to vacuum at room temperature. In this study, several carbon sorbents were fabricated and tested for ammonia sorption. Ammonia-sorption capacity was related to carbon pore structure characteristics, and the temperature of oxidative carbon-surface treatment was optimized for enhanced ammonia-sorption performance.

Genomic Encyclopedia of Bacteria and Archaea: Sequencing a Myriad of Type Strains

KAUST Repository

Kyrpides, Nikos C.; Hugenholtz, Philip; Eisen, Jonathan A.; Woyke, Tanja; Gö ker, Markus; Parker, Charles T.; Amann, Rudolf; Beck, Brian J.; Chain, Patrick S. G.; Chun, Jongsik; Colwell, Rita R.; Danchin, Antoine; Dawyndt, Peter; Dedeurwaerdere, Tom; DeLong, Edward F.; Detter, John C.; De Vos, Paul; Donohue, Timothy J.; Dong, Xiu-Zhu; Ehrlich, Dusko S.; Fraser, Claire; Gibbs, Richard; Gilbert, Jack; Gilna, Paul; Glö ckner, Frank Oliver; Jansson, Janet K.; Keasling, Jay D.; Knight, Rob; Labeda, David; Lapidus, Alla; Lee, Jung-Sook; Li, Wen-Jun; MA, Juncai; Markowitz, Victor; Moore, Edward R. B.; Morrison, Mark; Meyer, Folker; Nelson, Karen E.; Ohkuma, Moriya; Ouzounis, Christos A.; Pace, Norman; Parkhill, Julian; Qin, Nan; Rossello-Mora, Ramon; Sikorski, Johannes; Smith, David; Sogin, Mitch; Stevens, Rick; Stingl, Ulrich; Suzuki, Ken-ichiro; Taylor, Dorothea; Tiedje, Jim M.; Tindall, Brian; Wagner, Michael; Weinstock, George; Weissenbach, Jean; White, Owen; Wang, Jun; Zhang, Lixin; Zhou, Yu-Guang; Field, Dawn; Whitman, William B.; Garrity, George M.; Klenk, Hans Peter

2014-01-01

Microbes hold the key to life. They hold the secrets to our past (as the descendants of the earliest forms of life) and the prospects for our future (as we mine their genes for solutions to some of the planet's most pressing problems, from global warming to antibiotic resistance). However, the piecemeal approach that has defined efforts to study microbial genetic diversity for over 20 years and in over 30,000 genome projects risks squandering that promise. These efforts have covered less than 20% of the diversity of the cultured archaeal and bacterial species, which represent just 15% of the overall known prokaryotic diversity. Here we call for the funding of a systematic effort to produce a comprehensive genomic catalog of all cultured Bacteria and Archaea by sequencing, where available, the type strain of each species with a validly published name (currently∼11,000). This effort will provide an unprecedented level of coverage of our planet's genetic diversity, allow for the large-scale discovery of novel genes and functions, and lead to an improved understanding of microbial evolution and function in the environment.

Viruses of the Archaea

DEFF Research Database (Denmark)

Prangishvili,, David; Basta, Tamara; Garrett, Roger Antony

2016-01-01

Viruses infecting members of Archaea, the third domain of life, constitute an integral, yet unique part of the virosphere. Many of these viruses, specifically the species that infect hyperthermophilic hosts, display morphotypes – for example, bottle shaped, spindle shaped, droplet shaped, coil sh...

Tide as steering factor in structuring archaeal and bacterial ammonia-oxidizing communities in mangrove forest soils dominated by Avicennia germinans and Rhizophora mangle

NARCIS (Netherlands)

Marcos, Magali S.; Barboza, A.D.H.; Keijzer, R.M.; Laanbroek, H.J.

2018-01-01

Mangrove species are adapted to grow at specific zones in a tidal gradient. Here we tested the hypothesis that the archaeal and bacterial ammonia-oxidizing microbial communities differ in soils dominated by the mangrove species Avicennia germinans and Rhizophora mangle. Two of the sampling locations

Intercellular wiring enables electron transfer between methanotrophic archaea and bacteria.

Science.gov (United States)

Wegener, Gunter; Krukenberg, Viola; Riedel, Dietmar; Tegetmeyer, Halina E; Boetius, Antje

2015-10-22

The anaerobic oxidation of methane (AOM) with sulfate controls the emission of the greenhouse gas methane from the ocean floor. In marine sediments, AOM is performed by dual-species consortia of anaerobic methanotrophic archaea (ANME) and sulfate-reducing bacteria (SRB) inhabiting the methane-sulfate transition zone. The biochemical pathways and biological adaptations enabling this globally relevant process are not fully understood. Here we study the syntrophic interaction in thermophilic AOM (TAOM) between ANME-1 archaea and their consortium partner SRB HotSeep-1 (ref. 6) at 60 °C to test the hypothesis of a direct interspecies exchange of electrons. The activity of TAOM consortia was compared to the first ANME-free culture of an AOM partner bacterium that grows using hydrogen as the sole electron donor. The thermophilic ANME-1 do not produce sufficient hydrogen to sustain the observed growth of the HotSeep-1 partner. Enhancing the growth of the HotSeep-1 partner by hydrogen addition represses methane oxidation and the metabolic activity of ANME-1. Further supporting the hypothesis of direct electron transfer between the partners, we observe that under TAOM conditions, both ANME and the HotSeep-1 bacteria overexpress genes for extracellular cytochrome production and form cell-to-cell connections that resemble the nanowire structures responsible for interspecies electron transfer between syntrophic consortia of Geobacter. HotSeep-1 highly expresses genes for pili production only during consortial growth using methane, and the nanowire-like structures are absent in HotSeep-1 cells isolated with hydrogen. These observations suggest that direct electron transfer is a principal mechanism in TAOM, which may also explain the enigmatic functioning and specificity of other methanotrophic ANME-SRB consortia.

ADP-dependent Phosphofructokinases in Mesophilic and Thermophilic Methanogenic Archaea

NARCIS (Netherlands)

Verhees, C.H.; Tuininga, J.E.; Kengen, S.W.M.; Stams, A.J.M.; Oost, van der J.; Vos, de W.M.

2001-01-01

Phosphofructokinase (PFK) is a key enzyme of the glycolytic pathway in all domains of life. Two related PFKs, ATP-dependent and PPi-dependent PFK, have been distinguished in bacteria and eucarya, as well as in some archaea. Hyperthermophilic archaea of the order Thermococcales, including Pyrococcus

Direct growth of cerium oxide nanorods on diverse substrates for superhydrophobicity and corrosion resistance

International Nuclear Information System (INIS)

Cho, Young Jun; Jang, Hanmin; Lee, Kwan-Soo; Kim, Dong Rip

2015-01-01

Graphical abstract: - Highlights: • Cerium oxide nanorods were uniformly grown on diverse substrates. • Changes in growth conditions led to morphology evolution of cerium oxide nanostructures. • The grown cerium oxide nanostructures were single or poly crystalline. • Direct growth of cerium oxide nanorods made the diverse substrates superhydrophobic and anti-corrosive without any surface modifiers. - Abstract: Superhydrophobic surfaces with anti-corrosion properties have attracted great interest in many industrial fields, particularly to enhance the thermal performance of offshore applications such as heat exchangers, pipelines, power plants, and platform structures. Nanostructures with hydrophobic materials have been widely utilized to realize superhydrophobicity of surfaces, and cerium oxide has been highlighted due to its good corrosion resistive and intrinsically hydrophobic properties. However, few studies of direct growth of cerium oxide nanostructures on diverse substrates have been reported. Herein we report a facile hydrothermal method to directly grow cerium oxide nanorods on diverse substrates, such as aluminum alloy, stainless steel, titanium, and silicon. Diverse substrates with cerium oxide nanorods exhibited superhydrophobicity with no hydrophobic modifiers on their surfaces, and showed good corrosion resistive properties in corrosive medium. We believe our method could pave the way for realization of scalable and sustainable corrosion resistive superhydrophobic surfaces in many industrial fields

Direct growth of cerium oxide nanorods on diverse substrates for superhydrophobicity and corrosion resistance

Energy Technology Data Exchange (ETDEWEB)

Cho, Young Jun; Jang, Hanmin; Lee, Kwan-Soo [School of Mechanical Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Kim, Dong Rip, E-mail: dongrip@hanyang.ac.kr [School of Mechanical Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Institute of Nano Science and Technology, Hanyang University, Seoul 133-791 (Korea, Republic of)

2015-06-15

Graphical abstract: - Highlights: • Cerium oxide nanorods were uniformly grown on diverse substrates. • Changes in growth conditions led to morphology evolution of cerium oxide nanostructures. • The grown cerium oxide nanostructures were single or poly crystalline. • Direct growth of cerium oxide nanorods made the diverse substrates superhydrophobic and anti-corrosive without any surface modifiers. - Abstract: Superhydrophobic surfaces with anti-corrosion properties have attracted great interest in many industrial fields, particularly to enhance the thermal performance of offshore applications such as heat exchangers, pipelines, power plants, and platform structures. Nanostructures with hydrophobic materials have been widely utilized to realize superhydrophobicity of surfaces, and cerium oxide has been highlighted due to its good corrosion resistive and intrinsically hydrophobic properties. However, few studies of direct growth of cerium oxide nanostructures on diverse substrates have been reported. Herein we report a facile hydrothermal method to directly grow cerium oxide nanorods on diverse substrates, such as aluminum alloy, stainless steel, titanium, and silicon. Diverse substrates with cerium oxide nanorods exhibited superhydrophobicity with no hydrophobic modifiers on their surfaces, and showed good corrosion resistive properties in corrosive medium. We believe our method could pave the way for realization of scalable and sustainable corrosion resistive superhydrophobic surfaces in many industrial fields.

Evaluating four mathematical models for nitrous oxide production by autotrophic ammonia-oxidizing bacteria.

Science.gov (United States)

Ni, Bing-Jie; Yuan, Zhiguo; Chandran, Kartik; Vanrolleghem, Peter A; Murthy, Sudhir

2013-01-01

There is increasing evidence showing that ammonia-oxidizing bacteria (AOB) are major contributors to N(2)O emissions from wastewater treatment plants (WWTPs). Although the fundamental metabolic pathways for N(2)O production by AOB are now coming to light, the mechanisms responsible for N(2)O production by AOB in WWTP are not fully understood. Mathematical modeling provides a means for testing hypotheses related to mechanisms and triggers for N(2)O emissions in WWTP, and can then also become a tool to support the development of mitigation strategies. This study examined the ability of four mathematical model structures to describe two distinct mechanisms of N(2)O production by AOB. The production mechanisms evaluated are (1) N(2)O as the final product of nitrifier denitrification with NO(2)- as the terminal electron acceptor and (2) N(2)O as a byproduct of incomplete oxidation of hydroxylamine (NH(2)OH) to NO(2)-. The four models were compared based on their ability to predict N(2)O dynamics observed in three mixed culture studies. Short-term batch experimental data were employed to examine model assumptions related to the effects of (1) NH4+ concentration variations, (2) dissolved oxygen (DO) variations, (3) NO(2)- accumulations and (4) NH(2OH as an externally provided substrate. The modeling results demonstrate that all these models can generally describe the NH4+, NO(2)-, and NO(3)- data. However, none of these models were able to reproduce all measured N(2)O data. The results suggest that both the denitrification and NH(2)OH pathways may be involved in N(2)O production and could be kinetically linked by a competition for intracellular reducing equivalents. A unified model capturing both mechanisms and their potential interactions needs to be developed with consideration of physiological complexity. Copyright © 2012 Wiley Periodicals, Inc.

Synthesis of Ru nanoparticles confined in magnesium oxide-modified mesoporous alumina and their enhanced catalytic performance during ammonia decomposition

KAUST Repository

Tan, Hua

2012-09-01

In this work, Ru nanoparticles confined in the channels of ordered mesoporous alumina (MA) and magnesium oxide-modified ordered MA are prepared for the first time via a two-solvent technique, combined with the amorphous citrate route. Structural characterizations reveal that uniform 2-3 nm Ru nanoparticles are highly dispersed in the blockage-free channels of mesoporous supports. The Ru nanoparticles confined in MA modified with 20% molar ratio magnesium oxide exhibited a high catalytic activity and stability during ammonia decomposition due to the optimized particle size, basic support, lack of chlorine, and confined space provided by the channels of the mesoporous supports. © 2012 Elsevier B.V. All rights reserved.

Synthesis of Ru nanoparticles confined in magnesium oxide-modified mesoporous alumina and their enhanced catalytic performance during ammonia decomposition

KAUST Repository

Tan, Hua; Li, Kun; Sioud, Salim; Cha, Dong Kyu; Amad, Maan H.; Hedhili, Mohamed N.; Al-Talla, Zeyad

2012-01-01

In this work, Ru nanoparticles confined in the channels of ordered mesoporous alumina (MA) and magnesium oxide-modified ordered MA are prepared for the first time via a two-solvent technique, combined with the amorphous citrate route. Structural characterizations reveal that uniform 2-3 nm Ru nanoparticles are highly dispersed in the blockage-free channels of mesoporous supports. The Ru nanoparticles confined in MA modified with 20% molar ratio magnesium oxide exhibited a high catalytic activity and stability during ammonia decomposition due to the optimized particle size, basic support, lack of chlorine, and confined space provided by the channels of the mesoporous supports. © 2012 Elsevier B.V. All rights reserved.

Stable isotope probing and dynamic loading experiments provide insight into the ecophysiology of novel ammonia oxidizers in rapid gravity sand filters

DEFF Research Database (Denmark)

Fowler, Jane; Palomo, Alejandro; Gülay, Arda

to elucidate the differences in ecophysiology between the ammonia oxidizing clades that enable them to co-exist in this unique environment. Experiments were conducted using sand columns designed and operated to mimic the conditions in the full-scale parent RSF. RNA and DNA stable isotope probing based on 13C......-bicarbonate incorporation during continuous feeding with either ammonium or nitrite as sole energy source implicated Nitrospira spp. and certain ‘heterotrophic’ bacteria in addition to Nitrosomonas spp. in autotrophy during ammonium oxidation in RSFs. Further experimentation aimed to elucidate the ecophysiology of each...

In-vitro archaeacidal activity of biocides against human-associated archaea.

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Saber Khelaifia

Full Text Available BACKGROUND: Several methanogenic archaea have been detected in the human intestinal microbiota. These intestinal archaea may contaminate medical devices such as colonoscopes. However, no biocide activity has been reported among these human-associated archaea. METHODOLOGY: The minimal archaeacidal concentration (MAC of peracetic acid, chlorhexidine, squalamine and twelve parent synthetic derivatives reported in this study was determined against five human-associated methanogenic archaea including Methanobrevibacter smithii, Methanobrevibacter oralis, Methanobrevibacter arboriphilicus, Methanosphaera stadtmanae, Methanomassiliicoccus luminyensis and two environmental methanogens Methanobacterium beijingense and Methanosaeta concilii by using a serial dilution technique in Hungates tubes. PRINCIPAL FINDINGS: MAC of squalamine derivative S1 was 0.05 mg/L against M. smithii strains, M. oralis, M. arboriphilicus, M. concilii and M. beijingense whereas MAC of squalamine and derivatives S2-S12 varied from 0.5 to 5 mg/L. For M. stadtmanae and M. luminyensis, MAC of derivative S1 was 0.1 mg/L and varied from 1 to ≥ 10 mg/L for squalamine and its parent derivatives S2-S12. Under the same experimental conditions, chlorhexidine and peracetic acid lead to a MAC of 0.2 and 1.5 mg/L, respectively against all tested archaea. CONCLUSIONS/SIGNIFICANCE: Squalamine derivative S1 exhibited a 10-200 higher archaeacidal activity than other tested squalamine derivatives, on the majority of human-associated archaea. As previously reported and due to their week corrosivity and their wide spectrum of antibacterial and antifungal properties, squalamine and more precisely derivative S1 appear as promising compounds to be further tested for the decontamination of medical devices contaminated by human-associated archaea.

Impact Assessment and Environmental Evaluation of Various Ammonia Production Processes

Science.gov (United States)

Bicer, Yusuf; Dincer, Ibrahim; Vezina, Greg; Raso, Frank

2017-05-01

In the current study, conventional resources-based ammonia generation routes are comparatively studied through a comprehensive life cycle assessment. The selected ammonia generation options range from mostly used steam methane reforming to partial oxidation of heavy oil. The chosen ammonia synthesis process is the most common commercially available Haber-Bosch process. The essential energy input for the methods are used from various conventional resources such as coal, nuclear, natural gas and heavy oil. Using the life cycle assessment methodology, the environmental impacts of selected methods are identified and quantified from cradle to gate. The life cycle assessment outcomes of the conventional resources based ammonia production routes show that nuclear electrolysis-based ammonia generation method yields the lowest global warming and climate change impacts while the coal-based electrolysis options bring higher environmental problems. The calculated greenhouse gas emission from nuclear-based electrolysis is 0.48 kg CO2 equivalent while it is 13.6 kg CO2 per kg of ammonia for coal-based electrolysis method.

The common ancestor of archaea and eukarya was not an archaeon.

Science.gov (United States)

Forterre, Patrick

2013-01-01

It is often assumed that eukarya originated from archaea. This view has been recently supported by phylogenetic analyses in which eukarya are nested within archaea. Here, I argue that these analyses are not reliable, and I critically discuss archaeal ancestor scenarios, as well as fusion scenarios for the origin of eukaryotes. Based on recognized evolutionary trends toward reduction in archaea and toward complexity in eukarya, I suggest that their last common ancestor was more complex than modern archaea but simpler than modern eukaryotes (the bug in-between scenario). I propose that the ancestors of archaea (and bacteria) escaped protoeukaryotic predators by invading high temperature biotopes, triggering their reductive evolution toward the "prokaryotic" phenotype (the thermoreduction hypothesis). Intriguingly, whereas archaea and eukarya share many basic features at the molecular level, the archaeal mobilome resembles more the bacterial than the eukaryotic one. I suggest that selection of different parts of the ancestral virosphere at the onset of the three domains played a critical role in shaping their respective biology. Eukarya probably evolved toward complexity with the help of retroviruses and large DNA viruses, whereas similar selection pressure (thermoreduction) could explain why the archaeal and bacterial mobilomes somehow resemble each other.

Spatiotemporal Dynamics of Ammonia-Oxidizing Thaumarchaeota in Distinct Arctic Water Masses

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Oliver Müller

2018-01-01

Full Text Available One of the most abundant archaeal groups on Earth is the Thaumarchaeota. They are recognized as major contributors to marine ammonia oxidation, a crucial step in the biogeochemical cycling of nitrogen. Their universal success is attributed to a high genomic flexibility and niche adaptability. Based on differences in the gene coding for ammonia monooxygenase subunit A (amoA, two different ecotypes with distinct distribution patterns in the water column have been identified. We used high-throughput sequencing of 16S rRNA genes combined with archaeal amoA functional gene clone libraries to investigate which environmental factors are driving the distribution of Thaumarchaeota ecotypes in the Atlantic gateway to the Arctic Ocean through an annual cycle in 2014. We observed the characteristic vertical pattern of Thaumarchaeota abundance with high values in the mesopelagic (>200 m water throughout the entire year, but also in the epipelagic (<200 m water during the dark winter months (January, March and November. The Thaumarchaeota community was dominated by three OTUs which on average comprised 76% ± 11 and varied in relative abundance according to water mass characteristics and not to depth or ammonium concentration, as suggested in previous studies. The ratios of the abundance of the different OTU types were similar to that of the functional amoA water cluster types. Together, this suggests a strong selection of ecotypes within different water masses, supporting the general idea of water mass characteristics as an important factor in defining microbial community structure. If indeed, as suggested in this study, Thaumarchaeota population dynamics are controlled by a set of factors, described here as water mass characteristics and not just depth alone, then changes in water mass flow will inevitably affect the distribution of the different ecotypes.

Linking the Composition of Bacterial and Archaeal Communities to Characteristics of Soil and Flora Composition in the Atlantic Rainforest

Science.gov (United States)

Lima-Perim, Julia Elidia; Romagnoli, Emiliana Manesco; Dini-Andreote, Francisco; Durrer, Ademir; Dias, Armando Cavalcante Franco; Andreote, Fernando Dini

2016-01-01

The description of microbiomes as intrinsic fractions of any given ecosystem is an important issue, for instance, by linking their compositions and functions with other biotic and abiotic components of natural systems and hosts. Here we describe the archaeal and bacterial communities from soils of the Atlantic Rainforest in Brazil. Based on the comparison of three areas located along an altitudinal gradient—namely, Santa Virginia, Picinguaba and Restinga—we detected the most abundant groups of Bacteria (Acidobacteria and Proteobacteria) and Archaea (Thaumarchaeota, Crenarchaeota and Euryarchaeota). The particular composition of such communities in each of these areas was first evidenced by PCR-DGGE patterns [determined for Bacteria, Archaea and ammonia-oxidizing organisms—ammonia-oxidizing archaea (AOA) and bacteria (AOB)]. Moreover, sequence-based analysis provided a better resolution of communities, which indicated distinct frequencies of archaeal phyla and bacterial OTUs across areas. We found, as indicated by the Mantel test and multivariate analyses, a potential effect of the flora composition that outpaces the effect of soil characteristics (either physical and chemical) influencing the assembly of these microbial communities in soils. Our results indicate a collective role of the ecosystem underlying observed differences in microbial communities in these soils. Particularly, we posit that rainforest preservation also needs to take into account the maintenance of the soil biodiversity, as this is prompted to influence major processes that affect ecosystem functioning. PMID:26752633

Linking the Composition of Bacterial and Archaeal Communities to Characteristics of Soil and Flora Composition in the Atlantic Rainforest.

Science.gov (United States)

Lima-Perim, Julia Elidia; Romagnoli, Emiliana Manesco; Dini-Andreote, Francisco; Durrer, Ademir; Dias, Armando Cavalcante Franco; Andreote, Fernando Dini

2016-01-01

The description of microbiomes as intrinsic fractions of any given ecosystem is an important issue, for instance, by linking their compositions and functions with other biotic and abiotic components of natural systems and hosts. Here we describe the archaeal and bacterial communities from soils of the Atlantic Rainforest in Brazil. Based on the comparison of three areas located along an altitudinal gradient-namely, Santa Virginia, Picinguaba and Restinga-we detected the most abundant groups of Bacteria (Acidobacteria and Proteobacteria) and Archaea (Thaumarchaeota, Crenarchaeota and Euryarchaeota). The particular composition of such communities in each of these areas was first evidenced by PCR-DGGE patterns [determined for Bacteria, Archaea and ammonia-oxidizing organisms-ammonia-oxidizing archaea (AOA) and bacteria (AOB)]. Moreover, sequence-based analysis provided a better resolution of communities, which indicated distinct frequencies of archaeal phyla and bacterial OTUs across areas. We found, as indicated by the Mantel test and multivariate analyses, a potential effect of the flora composition that outpaces the effect of soil characteristics (either physical and chemical) influencing the assembly of these microbial communities in soils. Our results indicate a collective role of the ecosystem underlying observed differences in microbial communities in these soils. Particularly, we posit that rainforest preservation also needs to take into account the maintenance of the soil biodiversity, as this is prompted to influence major processes that affect ecosystem functioning.

Diversity of antisense and other non-coding RNAs in Archaea revealed by comparative small RNA sequencing in four Pyrobaculum species

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David L Bernick

2012-07-01

Full Text Available A great diversity of small, non-coding RNA molecules with roles in gene regulation and RNA processing have been intensely studied in eukaryotic and bacterial model organisms, yet our knowledge of possible parallel roles for small RNAs in archaea is limited. We employed RNA-seq to identify novel small RNA across multiple species of the hyperthermophilic genus Pyrobaculum, known for unusual RNA gene characteristics. By comparing transcriptional data collected in parallel among four species, we were able to identify conserved RNA genes fitting into known and novel families. Among our findings, we highlight three novel cis-antisense small RNAs encoded opposite to key regulatory (ferric uptake regulator, metabolic (triose-phosphate isomerase, and core transcriptional apparatus genes (transcription factor B. We also found a large increase in the number of conserved C/D box small RNA genes over what had been previously recognized; many of these genes are encoded antisense to protein coding genes. The conserved opposition to orthologous genes across the Pyrobaculum genus suggests similarities to other cis-antisense regulatory systems. Furthermore, the genus-specific nature of these small RNAs indicates they are relatively recent, stable adaptations.

Diversity and Distribution of Archaea Community along a Stratigraphic Permafrost Profile from Qinghai-Tibetan Plateau, China

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Shiping Wei

2014-01-01

Full Text Available Accompanying the thawing permafrost expected to result from the climate change, microbial decomposition of the massive amounts of frozen organic carbon stored in permafrost is a potential emission source of greenhouse gases, possibly leading to positive feedbacks to the greenhouse effect. In this study, the community composition of archaea in stratigraphic soils from an alpine permafrost of Qinghai-Tibetan Plateau was investigated. Phylogenic analysis of 16S rRNA sequences revealed that the community was predominantly constituted by Crenarchaeota and Euryarchaeota. The active layer contained a proportion of Crenarchaeota at 51.2%, with the proportion of Euryarchaeota at 48.8%, whereas the permafrost contained 41.2% Crenarchaeota and 58.8% Euryarchaeota, based on 16S rRNA gene sequence analysis. OTU1 and OTU11, affiliated to Group 1.3b/MCG-A within Crenarchaeota and the unclassified group within Euryarchaeota, respectively, were widely distributed in all sediment layers. However, OTU5 affiliated to Group 1.3b/MCG-A was primarily distributed in the active layers. Sequence analysis of the DGGE bands from the 16S rRNAs of methanogenic archaea showed that the majority of methanogens belonged to Methanosarcinales and Methanomicrobiales affiliated to Euryarchaeota and the uncultured ZC-I cluster affiliated to Methanosarcinales distributed in all the depths along the permafrost profile, which indicated a dominant group of methanogens occurring in the cold ecosystems.

Metagenomic potential for and diversity of N-cycle driving microorganisms in the Bothnian Sea sediment.

Science.gov (United States)

Rasigraf, Olivia; Schmitt, Julia; Jetten, Mike S M; Lüke, Claudia

2017-08-01

The biological nitrogen cycle is driven by a plethora of reactions transforming nitrogen compounds between various redox states. Here, we investigated the metagenomic potential for nitrogen cycle of the in situ microbial community in an oligotrophic, brackish environment of the Bothnian Sea sediment. Total DNA from three sediment depths was isolated and sequenced. The characterization of the total community was performed based on 16S rRNA gene inventory using SILVA database as reference. The diversity of diagnostic functional genes coding for nitrate reductases (napA;narG), nitrite:nitrate oxidoreductase (nxrA), nitrite reductases (nirK;nirS;nrfA), nitric oxide reductase (nor), nitrous oxide reductase (nosZ), hydrazine synthase (hzsA), ammonia monooxygenase (amoA), hydroxylamine oxidoreductase (hao), and nitrogenase (nifH) was analyzed by blastx against curated reference databases. In addition, Polymerase chain reaction (PCR)-based amplification was performed on the hzsA gene of anammox bacteria. Our results reveal high genomic potential for full denitrification to N 2 , but minor importance of anaerobic ammonium oxidation and dissimilatory nitrite reduction to ammonium. Genomic potential for aerobic ammonia oxidation was dominated by Thaumarchaeota. A higher diversity of anammox bacteria was detected in metagenomes than with PCR-based technique. The results reveal the importance of various N-cycle driving processes and highlight the advantage of metagenomics in detection of novel microbial key players. © 2017 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

Nitrogen fate model for gas-phase ammonia-enhanced in situ bioventing

International Nuclear Information System (INIS)

Marshall, T.R.

1995-01-01

Subsurface bioremediation of contaminants is sometimes limited by the availability of nitrogen. Introduction of gaseous ammonia to the subsurface is a feasible and economical approach to enhance biodegradation in some environments. A gaseous nutrient source may be a practical option for sites where surface application of liquid nutrients is not possible, such as sites with shallow groundwater or sites with surface operations. A conceptual nitrogen fate model was developed to provide remediation scientists and engineers with some practical guidelines in the use of ammonia-enhanced bioventing. Ammonia supplied to the subsurface dissolves readily in soil moisture and sorbs strongly to soil particles. The ammonium ion is the preferred nutrient form of many microorganisms. Some of the ammonia will be converted to nitrate by ammonia-oxidizing organisms. Field monitoring data from an operating ammonia-enhanced bioventing remediation site for diesel fuel contamination are presented. Conservative additions of ammonia promoted appreciable increases in evolved carbon dioxide and rate of oxygen utilization. An overabundance of added ammonia promoted formation of methane from likely anaerobic hydrocarbon degradation in the presence of nitrate as the electron acceptor

The unique features of glycolytic pathways in Archaea.

Science.gov (United States)

Verhees, Corné H; Kengen, Servé W M; Tuininga, Judith E; Schut, Gerrit J; Adams, Michael W W; De Vos, Willem M; Van Der Oost, John

2003-10-15

An early divergence in evolution has resulted in two prokaryotic domains, the Bacteria and the Archaea. Whereas the central metabolic routes of bacteria and eukaryotes are generally well-conserved, variant pathways have developed in Archaea involving several novel enzymes with a distinct control. A spectacular example of convergent evolution concerns the glucose-degrading pathways of saccharolytic archaea. The identification, characterization and comparison of the glycolytic enzymes of a variety of phylogenetic lineages have revealed a mosaic of canonical and novel enzymes in the archaeal variants of the Embden-Meyerhof and the Entner-Doudoroff pathways. By means of integrating results from biochemical and genetic studies with recently obtained comparative and functional genomics data, the structure and function of the archaeal glycolytic routes, the participating enzymes and their regulation are re-evaluated.

Impact of dicyandiamide on emissions of nitrous oxide, nitric oxide and ammonia from agricultural field in the North China Plain.

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Zhou, Yizhen; Zhang, Yuanyuan; Tian, Di; Mu, Yujing

2016-02-01

Nitrous oxide (N2O), nitric oxide (NO) and ammonia (NH3) emissions from an agricultural field in the North China Plain were compared for three treatments during a whole maize growing period from 26 June to 11 October, 2012. Compared with the control treatment (without fertilization, designated as CK), remarkable pulse emissions of N2O, NO and NH3 were observed from the normal fertilization treatment (designated as NP) just after fertilization, whereas only N2O and NH3 pulse emissions were evident from the nitrification inhibitor treatment (designated as ND). The reduction proportions of N2O and NO emissions from the ND treatment compared to those from the NP treatment during the whole maize growing period were 31% and 100%, respectively. A measurable increase of NH3 emission from the ND treatment was found with a cumulative NH3 emission of 3.8 ± 1.2 kg N/ha, which was 1.4 times greater than that from the NP treatment (2.7 ± 0.7 kg N/ha). Copyright © 2015. Published by Elsevier B.V.

Nitrosomonas communis strain YNSRA, an ammonia-oxidizing bacterium, isolated from the reed rhizoplane in an aquaponics plant.

Science.gov (United States)

Tokuyama, Tatsuaki; Mine, Atsusi; Kamiyama, Kaoru; Yabe, Ryuichi; Satoh, Kazuo; Matsumoto, Hirotoshi; Takahashi, Reiji; Itonaga, Koji

2004-01-01

An ammonia-oxidizing bacterium (strain YNSRA) was isolated from the rhizoplane of the reed (Phragmites communis) used in an aquaponics plant which is a wastewater treatment plant. Strain YNSRA was identified as Nitrosomonas communis by taxonomic studies. The hydroxylamine-cytochrome c reductase (HCR) of strain YNSRA was found to have a higher activity (25.60 u/mg) than that of Nitrosomonas europaea ATCC25978T (8.94 u/mg). Ribulose-1,5-bisphosphate carboxylase (RubisCO) activity was detected at very low levels in strain YNSRA, whereas strain ATCC25978T had definite activity.

Responses of soil microbial biomass and bacterial community structure to closed-off management (an ecological natural restoration measures): A case study of Dongting Lake wetland, middle China.

Science.gov (United States)

Dai, Juan; Wu, Haipeng; Zhang, Chang; Zeng, Guangming; Liang, Jie; Guo, Shenglian; Li, Xiaodong; Huang, Lu; Lu, Lunhui; Yuan, Yujie

2016-09-01

Soil microbial biomass (SMB) and bacterial community structure, which are critical to global ecosystem and fundamental ecological processes, are sensitive to anthropogenic activities and environmental conditions. In this study, we examined the possible effects of closed-off management (an ecological natural restoration measures, ban on anthropogenic activity, widely employed for many important wetlands) on SMB, soil bacterial community structure and functional marker genes of nitrogen cycling in Dongting Lake wetland. Soil samples were collected from management area (MA) and contrast area (CA: human activities, such as hunting, fishing and draining, are permitted) in November 2013 and April 2014. Soil properties, microbial biomass carbon (MBC), and bacterial community structure were investigated. Comparison of the values of MA and CA showed that SMB and bacterial community diversity of the MA had a significant increase after 7 years closed-off management. The mean value of Shannon-Weiner diversity index of MA and CA respectively were 2.85 and 2.07. The gene copy numbers of 16S rRNA and nosZ of MA were significant higher than those of CA. the gene copy numbers of ammonia-oxidizing archaea (AOA) and nirK of MA were significant lower than those of CA. However, there was no significant change in the gene copy numbers of ammonia-oxidizing bacteria (AOB) and nirS. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Nitrogen removal from wastewater by a catalytic oxidation method.

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Huang, T L; Macinnes, J M; Cliffe, K R

2001-06-01

The ammonia-containing waste produced in industries is usually characterized by high concentration and high temperature, and is not treatable by biological methods directly. In this study, a hydrophobic Pt/SDB catalyst was first used in a trickle-bed reactor to remove ammonia from wastewater. In the reactor, both stripping and catalytic oxidation occur simultaneously. It was found that higher temperature and higher oxygen partial pressure enhanced the ammonia removal. A reaction pathway, which involves oxidizing ammonia to nitric oxide, which then further reacts with ammonia to produce nitrogen and water, was confirmed. Small amounts of by-products, nitrites and nitrates were also detected in the resultant reaction solution. These compounds came from the absorption of nitrogen oxides. Both the minimum NO2- selectivity and maximum ammonia removal were achieved when the resultant pH of treated water was near 7.5 for a feed of unbuffered ammonia solution.

Nitrate reduction, nitrous oxide formation, and anaerobic ammonia oxidation to nitrite in the gut of soil-feeding termites (Cubitermes and Ophiotermes spp.)

KAUST Repository

Ngugi, David

2011-11-28

Soil-feeding termites play important roles in the dynamics of carbon and nitrogen in tropical soils. Through the mineralization of nitrogenous humus components, their intestinal tracts accumulate enormous amounts of ammonia, and nitrate and nitrite concentrations are several orders of magnitude above those in the ingested soil. Here, we studied the metabolism of nitrate in the different gut compartments of two Cubitermes and one Ophiotermes species using 15N isotope tracer analysis. Living termites emitted N 2 at rates ranging from 3.8 to 6.8nmolh -1 (g fresh wt.) -1. However, in homogenates of individual gut sections, denitrification was restricted to the posterior hindgut, whereas nitrate ammonification occurred in all gut compartments and was the prevailing process in the anterior gut. Potential rates of nitrate ammonification for the entire intestinal tract were tenfold higher than those of denitrification, implying that ammonification is the major sink for ingested nitrate in the intestinal tract of soil-feeding termites. Because nitrate is efficiently reduced already in the anterior gut, reductive processes in the posterior gut compartments must be fuelled by an endogenous source of oxidized nitrogen species. Quite unexpectedly, we observed an anaerobic oxidation of 15N-labelled ammonia to nitrite, especially in the P4 section, which is presumably driven by ferric iron; nitrification and anammox activities were not detected. Two of the termite species also emitted substantial amounts of N 2O, ranging from 0.4 to 3.9nmolh -1 (g fresh wt.) -1, providing direct evidence that soil-feeding termites are a hitherto unrecognized source of this greenhouse gas in tropical soils. © 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.

Widespread Disulfide Bonding in Proteins from Thermophilic Archaea

OpenAIRE

Jorda, Julien; Yeates, Todd O.

2011-01-01

Disulfide bonds are generally not used to stabilize proteins in the cytosolic compartments of bacteria or eukaryotic cells, owing to the chemically reducing nature of those environments. In contrast, certain thermophilic archaea use disulfide bonding as a major mechanism for protein stabilization. Here, we provide a current survey of completely sequenced genomes, applying computational methods to estimate the use of disulfide bonding across the Archaea. Microbes belonging to the Crenarchaea...

System and method for controlling ammonia levels in a selective catalytic reduction catalyst using a nitrogen oxide sensor

Science.gov (United States)

None

2017-07-25

A system according to the principles of the present disclosure includes an air/fuel ratio determination module and an emission level determination module. The air/fuel ratio determination module determines an air/fuel ratio based on input from an air/fuel ratio sensor positioned downstream from a three-way catalyst that is positioned upstream from a selective catalytic reduction (SCR) catalyst. The emission level determination module selects one of a predetermined value and an input based on the air/fuel ratio. The input is received from a nitrogen oxide sensor positioned downstream from the three-way catalyst. The emission level determination module determines an ammonia level based on the one of the predetermined value and the input received from the nitrogen oxide sensor.

The Common Ancestor of Archaea and Eukarya Was Not an Archaeon

Directory of Open Access Journals (Sweden)

Patrick Forterre

2013-01-01

Full Text Available It is often assumed that eukarya originated from archaea. This view has been recently supported by phylogenetic analyses in which eukarya are nested within archaea. Here, I argue that these analyses are not reliable, and I critically discuss archaeal ancestor scenarios, as well as fusion scenarios for the origin of eukaryotes. Based on recognized evolutionary trends toward reduction in archaea and toward complexity in eukarya, I suggest that their last common ancestor was more complex than modern archaea but simpler than modern eukaryotes (the bug in-between scenario. I propose that the ancestors of archaea (and bacteria escaped protoeukaryotic predators by invading high temperature biotopes, triggering their reductive evolution toward the “prokaryotic” phenotype (the thermoreduction hypothesis. Intriguingly, whereas archaea and eukarya share many basic features at the molecular level, the archaeal mobilome resembles more the bacterial than the eukaryotic one. I suggest that selection of different parts of the ancestral virosphere at the onset of the three domains played a critical role in shaping their respective biology. Eukarya probably evolved toward complexity with the help of retroviruses and large DNA viruses, whereas similar selection pressure (thermoreduction could explain why the archaeal and bacterial mobilomes somehow resemble each other.

Activity and diversity of methane-oxidizing bacteria in glacier forefields on siliceous and calcareous bedrock