Nitrification Activity
Mostrando 13-24 de 45 artigos, teses e dissertações.
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13. Quantification of Ammonia-Oxidizing Bacteria and Factors Controlling Nitrification in Salt Marsh Sediments
To elucidate the geomicrobiological factors controlling nitrification in salt marsh sediments, a comprehensive approach involving sediment geochemistry, process rate measurements, and quantification of the genetic potential for nitrification was applied to three contrasting salt marsh habitats: areas colonized by the tall (TS) or short (SS) form of Spartina
American Society for Microbiology.
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14. Use of nitrifying activity measurements for describing the effect of salinity on nitrification in the Scheldt estuary.
Nitrifying activity measurements, carried out on freshly collected samples from an estuarine environment, show that the composition of the nitrifier population undergoes a progressive modification during the mixing of freshwater masses in seawater, with increasing tolerance to salt. As a result, the overall effect of increasing salinity on nitrification is m
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15. Use of Molecular and Isotopic Techniques To Monitor the Response of Autotrophic Ammonia-Oxidizing Populations of the β Subdivision of the Class Proteobacteria in Arable Soils to Nitrogen Fertilizer
This study examined the effects of NH4NO3 fertilizer on the size and activity of nitrifying, autotrophic, ammonia-oxidizing populations of the β subdivision of the class Proteobacteria in arable soils. Plots under different long-term fertilizer regimes were sampled before and after NH4NO3 additions, and the rates of nitrification were determined by 15N isot
American Society for Microbiology.
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16. Heterotrophic nitrification among denitrifiers.
Twelve denitrifying bacteria representing six genera were tested for an ability to nitrify pyruvic oxime heterotrophically. Six of these bacteria exhibited appreciable nitrification activity, yielding as much as 5.8 mM nitrite and little or no nitrate when grown in a mineral salts medium containing 7 mM pyruvic oxime and 0.05% yeast extract. Of the six activ
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17. Estimation of Nitrification and Denitrification from Microprofiles of Oxygen and Nitrate in Model Sediment Systems
The coupling between nitrification and denitrification and the regulation of these processes by oxygen were studied in freshwater sediment microcosms with O2 and NO3- microsensors. Depth profiles of nitrification (indicated as NO3- production), denitrification (indicated as NO3- consumption), and O2 consumption activities within the sediment were calculated
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18. Microelectrode Measurements of the Activity Distribution in Nitrifying Bacterial Aggregates
Microelectrodes for ammonium, oxygen, nitrate, and pH were used to study nitrifying aggregates grown in a fluidized-bed reactor. Local reactant fluxes and distribution of microbial activity could be determined from the microprofiles. The interfacial fluxes of the reactants closely reflected the stoichiometry of bacterial nitrification. Both ammonium consumpt
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19. Nitrification and Autotrophic Nitrifying Bacteria in a Hydrocarbon-Polluted Soil
In vitro ammonia-oxidizing bacteria are capable of oxidizing hydrocarbons incompletely. This transformation is accompanied by competitive inhibition of ammonia monooxygenase, the first key enzyme in nitrification. The effect of hydrocarbon pollution on soil nitrification was examined in situ. In a microcosm study, adding diesel fuel hydrocarbon to an unconta
American Society for Microbiology.
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20. Autotrophic Ammonia-Oxidizing Bacteria Contribute Minimally to Nitrification in a Nitrogen-Impacted Forested Ecosystem
Deposition rates of atmospheric nitrogenous pollutants to forests in the San Bernardino Mountains range east of Los Angeles, California, are the highest reported in North America. Acidic soils from the west end of the range are N-saturated and have elevated rates of N-mineralization, nitrification, and nitrate leaching. We assessed the impact of this heavy n
American Society for Microbiology.
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21. Competition between Ammonia-Oxidizing Bacteria and Benthic Microalgae
The abundance, activity, and diversity of ammonia-oxidizing bacteria (AOB) were studied in prepared microcosms with and without microphytobenthic activity. In the microcosm without alga activity, both AOB abundance, estimated by real-time PCR, and potential nitrification increased during the course of the experiment. AOB present in the oxic zone of these sed
American Society for Microbiology.
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22. A Bioluminescence Assay Using Nitrosomonas europaea for Rapid and Sensitive Detection of Nitrification Inhibitors
An expression vector for the luxAB genes, derived from Vibrio harveyi, was introduced into Nitrosomonas europaea. Although the recombinant strain produced bioluminescence due to the expression of the luxAB genes under normal growing conditions, the intensity of the light emission decreased immediately, in a time-and dose-dependent manner, with the addition o
American Society for Microbiology.
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23. Environmental Parameters Regulating Gaseous Nitrogen Losses from Two Forested Ecosystems via Nitrification and Denitrification †
Gaseous N losses from disturbed and reference forested watersheds at the Coweeta Hydrologic Laboratory in western North Carolina were studied by in situ N2O diffusion measurements and laboratory incubations throughout a 10-month period. Soil temperature, percent base saturation, and water-filled pore space accounted for 43% of the variation in in situ N2O di
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24. FORMATION OF NITRITE AND NITRATE BY ACTINOMYCETES AND FUNGI
Hirsch, P. (Cornell University, Ithaca, New York), L. Overrein, and M. Alexander. Formation of nitrite and nitrate by actinomycetes and fungi. J. Bacteriol. 82:442–448. 1961.—Nitrite was produced by strains of Mycobacterium, Nocardia, Streptomyces, Micromonospora, and Streptosporangium in media containing ammonium phosphate as the sole nitrogen source. T