Publications
| Title | Abstract | Year(sorted descending) Filter | PMID Filter |
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| isolation and characterization of cbbl and cbbs genes encoding form i ribulose-1,5-bisphosphate carboxylase/oxygenase large and small subunits in nitrosomonas sp. strain eni-11. | the cbbl and cbbs genes encoding form i ribulose-1,5-bisphosphate carboxylase/oxygenase (rubisco) large and small subunits in the ammonia-oxidizing bacterium nitrosomonas sp. strain eni-11 were cloned and sequenced. the deduced gene products, cbbl and cbbs, had 93 and 87% identity with thiobacillus intermedius cbbl and nitrobacter winogradskyi cbbs, respectively. expression of cbbl and cbbs in escherichia coli led to the detection of rubisco activity in the presence of 0.1 mm isopropyl-beta-d-th ... | 2002 | 12005060 |
| cooxidation of naphthalene and other polycyclic aromatic hydrocarbons by the nitrifying bacterium, nitrosomonas europaea. | the soil nitrifying bacterium nitrosomonas europaea has shown the ability to transform cometabolically naphthalene as well as other 2- and 3-ringed polycyclic aromatic hydrocarbons (pahs) to more oxidized products. all of the observed enzymatic reactions were inhibited by acetylene, a selective inhibitor of ammonia monooxygenase (amo). a strong inhibitory effect of naphthalene on ammonia oxidation by n. europaea was observed. naphthalene was readily oxidized by n. europaea and 2-naphthol was det ... | 2002 | 12713129 |
| grassland management regimens reduce small-scale heterogeneity and species diversity of beta-proteobacterial ammonia pxidizer populations. | the impact of soil management practices on ammonia oxidizer diversity and spatial heterogeneity was determined in improved (addition of n fertilizer), unimproved (no additions), and semi-improved (intermediate management) grassland pastures at the sourhope research station in scotland. ammonia oxidizer diversity within each grassland soil was assessed by pcr amplification of microbial community dna with both ammonia oxidizer-specific, 16s rrna gene (rdna) and functional, amoa, gene primers. pcr ... | 2002 | 11772604 |
| ammonia- and nitrite-oxidizing bacterial communities in a pilot-scale chloraminated drinking water distribution system. | 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 ... | 2002 | 11772611 |
| single-base-pair discrimination of terminal mismatches by using oligonucleotide microarrays and neural network analyses. | the effects of single-base-pair near-terminal and terminal mismatches on the dissociation temperature (t(d)) and signal intensity of short dna duplexes were determined by using oligonucleotide microarrays and neural network (nn) analyses. two perfect-match probes and 29 probes having a single-base-pair mismatch at positions 1 to 5 from the 5' terminus of the probe were designed to target one of two short sequences representing 16s rrna. nonequilibrium dissociation rates (i.e., melting profiles) ... | 2002 | 11772632 |
| quantification of nitrosomonas oligotropha-like ammonia-oxidizing bacteria and nitrospira spp. from full-scale wastewater treatment plants by competitive pcr. | utilizing the principle of competitive pcr, we developed two assays to enumerate nitrosomonas oligotropha-like ammonia-oxidizing bacteria and nitrite-oxidizing bacteria belonging to the genus nitrospira: the specificities of two primer sets, which were designed for two target regions, the amoa gene and nitrospira 16s ribosomal dna (rdna), were verified by dna sequencing. both assays were optimized and applied to full-scale, activated sludge wastewater treatment plant (wwtp) samples. if it was as ... | 2002 | 11772633 |
| diversity of ammonia monooxygenase operon in autotrophic ammonia-oxidizing bacteria. | autotrophic ammonia-oxidizing bacteria use the essential enzyme ammonia monooxygenase (amo) to transform ammonia to hydroxylamine. the amo operon consists of at least three genes, amoc, amoa, and amob; amoa encodes the subunit containing the putative enzyme active site. the use of the amo genes as functional markers for ammonia-oxidizing bacteria in environmental applications requires knowledge of the diversity of the amo operon on several levels: (1) the copy number of the operon in the genome, ... | 2002 | 11807563 |
| phylogeny and functional expression of ribulose 1,5-bisphosphate carboxylase/oxygenase from the autotrophic ammonia-oxidizing bacterium nitrosospira sp. isolate 40ki. | the autotrophic ammonia-oxidizing bacteria (aob), which play an important role in the global nitrogen cycle, assimilate co(2) by using ribulose 1,5-bisphosphate carboxylase/oxygenase (rubisco). here we describe the first detailed study of rubisco (cbb) genes and proteins from the aob. the cbbls genes from nitrosospira sp. isolate 40ki were cloned and sequenced. partial sequences of the rubisco large subunit (cbbl) from 13 other aob belonging to the beta and gamma subgroups of the class proteobac ... | 2002 | 11751824 |
| nitrosocyanin, a red cupredoxin-like protein from nitrosomonas europaea. | nitrosocyanin (nc), a soluble, red cu protein isolated from the ammonia-oxidizing autotrophic bacterium nitrosomonas europaea, is shown to be a homo-oligomer of 12 kda cu-containing monomers. oligonucleotides based on the amino acid sequence of the n-terminus and of the c-terminal tryptic peptide were used to sequence the gene by pcr. the translated protein sequence was significantly homologous with the mononuclear cupredoxins such as plastocyanin, azurin, or rusticyanin, the type 1 copper-bindi ... | 2002 | 11827513 |
| nitrite as a stimulus for ammonia-starved nitrosomonas europaea. | 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 accumulates and may subsequently inhibit ammonia oxidation. the maintenance of a high ammonia-oxidizing capacity during starvation is then nullified. in this study we demonstrated that cells of n. europaea sta ... | 2002 | 11872501 |
| solid-phase contact assay that uses a lux-marked nitrosomonas europaea reporter strain to estimate toxicity of bioavailable linear alkylbenzene sulfonate in soil. | information about in situ toxicity of the bioavailable pools of adsorptive soil pollutants is a prerequisite for proper ecological risk assessment in contaminated soils. such toxicity data may be obtained by assays allowing for direct exposure of introduced test microorganisms to the toxicants, as they appear in solid solution equilibria in the natural soil. we describe a novel sensitive solid-phase contact assay for in situ toxicity testing of soil pollutants based on a recombinant bioluminesce ... | 2002 | 12089034 |
| enumerating ammonia-oxidizing bacteria in environmental samples using competitive pcr. | primers targeting part of the ammonia-monooxygenase gene (amoa) have been used to detect and characterize ammonia-oxidizing bacteria (aob) in different environments. in this study, a quantitative polymerase chain reaction (pcr) technique using a competitive template for the amoa primer pair is described and evaluated. the method is based on addition of an internal standard to the pcr, a competitive template, which is amplified together with the template in the environmental sample. by adding dif ... | 2002 | 12133615 |
| exploration of inorganic c and n assimilation by soil microbes with time-of-flight secondary ion mass spectrometry. | stable c and n isotopes have long been used to examine properties of various c and n cycling processes in soils. unfortunately, relatively large sample sizes are needed for accurate gas phase isotope ratio mass spectrometric analysis. this limitation has prevented researchers from addressing c and n cycling issues on microbially meaningful scales. here we explored the use of time-of-flight secondary ion mass spectrometry (tof-sims) to detect 13c and 15n assimilation by individual bacterial cells ... | 2002 | 12147508 |
| use of natural zeolite to enhance nitrification in biofilter. | to enhance nitrification, natural zeolite and activated carbon were tested as a media in a biofilter to treat wastewater containing relatively high concentrations of tkn. using those media, the adsorption isotherms for ammonium ion were compared; the k values for natural zeolite and activated carbon were found to be 0.5117 and 0.0006, respectively. in comparison of the performance of the two media, two identical, lab-scale biofilters were then operated for 4 months. the effect of nh3-n loading r ... | 2002 | 12164639 |
| biodegradation of monohalogenated alkanes by soil nh(3)-oxidizing bacteria. | although cooxidative biodegradation of monohalogenated hydrocarbons has been well studied in the model nh(3)-oxidizing bacterium, nitrosomonas europaea, virtually no information exists about cooxidation of these compounds by native populations of nh(3)-oxidizing bacteria. to address this subject, nitrifying activity was stimulated to 125-400 nmol no(3)(-) produced g(-1) soil h(-1) by first incubating a ca(oh)(2)-amended, silt loam soil (ph 7.0+/-0.2) at field capacity (270 g h(2)o kg(-1) soil) w ... | 2002 | 12172622 |
| oxygen-limited autotrophic nitrification/denitrification by ammonia oxidisers enables upward motion towards more favourable conditions. | the hypothesis is formulated that in case of oxygen limitation in the sediment, nitrifiers switch from nitrification to oxygen-limited autotrophic nitrification-denitrification (oland) in order to survive and maintain activity. during oland, ammonium is oxidised using nitrite as e-acceptor to form dinitrogen gas. as an additional advantage they benefit from the gaseous n(2) formed as a means of transport. in this way, the nitrifiers can move out of the sediment and rise through the water column ... | 2002 | 12172626 |
| in situ characterization of nitrifiers in an activated sludge plant: detection of nitrobacter spp. | the purpose of this work was to investigate microbial ecology of nitrifiers at the genus level in a typical full-scale activated sludge plant. | 2002 | 12174041 |
| identification of active methylotroph populations in an acidic forest soil by stable-isotope probing. | stable-isotope probing (sip) is a culture-independent technique that enables the isolation of dna from micro-organisms that are actively involved in a specific metabolic process. in this study, sip was used to characterize the active methylotroph populations in forest soil (ph 3.5) microcosms that were exposed to (13)ch(3)oh or (13)ch(4). distinct (13)c-labelled dna ((13)c-dna) fractions were resolved from total community dna by cscl density-gradient centrifugation. analysis of 16s rdna sequence ... | 2002 | 12177327 |
| detection of proteobacteria from the rumen by pcr using methanotroph-specific primers. | to detect proteobacteria, including methanotrophs, from the rumen fluid and the bacteria inhabiting the rumen epithelium. | 2002 | 12180951 |
| oxygen-limited nitrogen removal in a lab-scale rotating biological contactor treating an ammonium-rich wastewater. | a lab-scale rotating biological contactor (rbc) was operated with the purpose of oxygen-limited (autotrophic) nitrification-denitrification of an ammonium-rich synthetic wastewater without chemical oxygen demand (cod). based on the field observations that rbcs receiving anaerobic effluents come to anoxic ammonium removal, the rbc was inoculated with methanogenic sludge. some 100 days after the addition of the anaerobic sludge to the reactor as a possible means of a rapid initiation of the nitrog ... | 2002 | 12188571 |
| molecular biology and biochemistry of ammonia oxidation by nitrosomonas europaea. | nitrosomonas europaea uses only nh(3), co(2) and mineral salts for growth and as such it is an obligate chemo-lithoautotroph. the oxidation of nh(3) is a two-step process catalyzed by ammonia monooxygenase (amo) and hydroxylamine oxidoreductase (hao). amo catalyzes the oxidation of nh(3) to nh(2)oh and hao catalyzes the oxidation of nh(2)oh to no(2)(-). amo is a membrane-bound enzyme composed of three subunits. hao is located in the periplasm and is a homotrimer with each subunit containing eigh ... | 2002 | 12209257 |
| production of gaseous nitrogen compounds in a novel process for ammonium removal. | the production of gaseous nitrogen compounds, particularly the greenhouse gas nitrous oxide, was investigated in a novel process for ammonium removal from wastewater. the process is based on the adsorption of ammonium on zeolite followed by bioregeneration. the zeolite serves the dual purpose of an ion exchanger and a physical carrier for nitrifying bacteria which bio-regenerate the ammonium saturated mineral. an analysis of the nitrifying population composition in the reactor fed with simulated ... | 2002 | 12216627 |
| structure and function of nitrifying biofilms as determined by molecular techniques and the use of microelectrodes. | the phylogenetic diversity of a nitrifying bacterial community of two types of nitrifying biofilms, a domestic wastewater biofilm and an autotrophic nitrifying biofilm grown on rotating disk reactors (rdr), was characterized by 16s ribosomal dna (rdna)-cloning analysis. thereafter, successional development of nitrifying the bacterial community within both biofilms was visualized in situ by fluorescent in situ hybridization (fish) wih a set of fluorescently labeled 16s rrna-targeted dna probes. i ... | 2002 | 12216629 |
| molecular analysis of ammonia-oxidizing bacterial populations in aerated-anoxic orbal processes. | aerated-anoxic processes operate under the principle that small additions of oxygen to an anoxic reactor induce simultaneous nitrification and denitrification. in these systems, ammonia oxidation in the anoxic zone can easily account for 30-50% of the total nitrification in the reactor, even though the dissolve oxygen concentration is usually below detection limit. to investigate whether the nitrification efficiency in aerated-anoxic processes was due to the presence of specialized ammonia-oxidi ... | 2002 | 12216636 |
| detection and quantification of expression of amoa by competitive reverse transcription-pcr. | ammonia oxidation by chemolithoautotrophic ammonia-oxidizing bacteria is an important step in the biological nitrogen removal process. the first conversion step, the oxidation of ammonia to hydroxylamine is catalyzed by ammonia monooxygenase (amo). to investigate the activity of ammonia oxidation, mrna (designated as amoa) encoding a subunit of amo was quantified by competitive reverse transcription (rt)-pcr. as a result, it was possible to detect and quantify amoa expression in cultured nitroso ... | 2002 | 12216637 |
| growth at low ammonium concentrations and starvation response as potential factors involved in niche differentiation among ammonia-oxidizing bacteria. | in nature, ammonia-oxidizing bacteria have to compete with heterotrophic bacteria and plants for limiting amounts of ammonium. previous laboratory experiments conducted with nitrosomonas europaea suggested that ammonia-oxidizing bacteria are weak competitors for ammonium. to obtain a better insight into possible methods of niche differentiation among ammonia-oxidizing bacteria, we carried out a growth experiment at low ammonium concentrations with n. europaea and the ammonia oxidizer g5-7, a clo ... | 2002 | 12324316 |
| melissa: a loop of interconnected bioreactors to develop life support in space. | the development of a loop of interconnected continuous bioreactors, aimed to provide life support in space, is reported. the complete loop concept consists of four bioreactors and one higher plant compartment. for its realization the continuous and controlled operation of the bioreactors is characterized, up to the pilot scale level, first for each individual reactor, second for the interconnected reactor operation. the results obtained with the two more advanced bioreactors in the micro ecologi ... | 2002 | 12385718 |
| anaerobic ammonia oxidation in the presence of nitrogen oxides (no(x)) by two different lithotrophs. | the anaerobic ammonia-oxidizing activity of the planctomycete candidatus "brocadia anammoxidans" was not inhibited by no concentrations up to 600 ppm and no2 concentrations up to 100 ppm. b. anammoxidans was able to convert (detoxify) no, which might explain the high no tolerance of this organism. in the presence of no2, the specific ammonia oxidation activity of b. anammoxidans increased, and nitrosomonas-like microorganisms recovered an no2-dependent anaerobic ammonia oxidation activity. addit ... | 2002 | 12406724 |
| effect of soil ammonium concentration on n2o release and on the community structure of ammonia oxidizers and denitrifiers. | the effect of ammonium addition (6.5, 58, and 395 microg of nh4+-n g [dry weight] of soil(-1)) on soil microbial communities was explored. for medium and high ammonium concentrations, increased n2o release rates and a shift toward a higher contribution of nitrification to n2o release occurred after incubation for 5 days at 4 degrees c. communities of ammonia oxidizers were assayed after 4 weeks of incubation by denaturant gradient gel electrophoresis (dgge) of the amoa gene coding for the small ... | 2002 | 12406765 |
| the roles of the three gene copies encoding hydroxylamine oxidoreductase in nitrosomonas europaea. | the nitrifying bacterium nitrosomonas europaea contains three copies of the gene (hao) encoding hydroxylamine oxidoreductase (hao), the second enzyme in the nitrification pathway which oxidizes nh(2)oh to no(2)(-). the nucleotide sequences of the hao genes differ by only one nucleotide. two of the three gene copies have identical promoter sequences, while the third promoter has a different nucleotide sequence. mutant strains with two of the three copies of hao inactivated were created by inserti ... | 2002 | 12420168 |
| cultivation-based and molecular approaches to characterisation of terrestrial and aquatic nitrifiers. | increased awareness of the metabolic diversity within autotrophic nitrifying bacteria has led to a re-evaluation of their role in the cycling of nitrogen in terrestrial and aquatic ecosystems. this has been accompanied by improvements in our ability to characterise natural populations of autotrophic ammonia oxidising bacteria through the application of molecular techniques. molecular approaches indicate considerable diversity within natural populations and the association of different groups of ... | 2002 | 12448715 |
| molecular characterization of microbial community in nitrate-removing activated sludge. | abstract the microbial community composition and dominant denitrifying populations in high-nitrate-removing (cr-i) and low-nitrate-removing (cr-ii) activated sludge from continuous bioreactors were investigated with most probable number (mpn) enumeration, fluorescence in situ hybridization (fish) and 16s rdna characterization. mpns of nitrate-reducing bacteria of sludge cr-i and sludge cr-ii were 2.82x10(7) and 2.69x10(4) colony-forming units ml(-1), respectively. eight denitrifying bacteria and ... | 2002 | 19709242 |
| nitrification in the schelde estuary: methodological aspects and factors influencing its activity. | abstract we present a 15-month dataset on nitrification measurements in the schelde estuary (belgium and the netherlands). nitrification was estimated using the n-serve sensitive dark (14)c-bicarbonate incorporation technique. a peak of nitrification activity was observed in the freshwater part of the estuary. downstream from this peak, nitrification declined, probably because of ammonium limitation. a range of nitrification inhibitors was tested on both a nitrosomonas europaea culture and estua ... | 2002 | 19709269 |
| validation of publication of new names and new combinations previously effectively published outside the ijsem. | 2001 | 11760931 | |
| detailed phylogeny of ammonia-oxidizing bacteria determined by rdna sequences and dna homology values. | a comparison of the phylogeny of 38 isolates of chemolithoautotrophic ammonia-oxidizing bacteria (aob) based on 16s rrna gene sequences, 16s-235 rdna intergenic spacer region (isr) sequences and species affiliations based on dna homology values was performed. the organisms studied all belong to the beta-subclass of the proteobacteria and included representatives of nitrosomonas, nitrosococcus and nitrosospira. the similarity values of the 16s rdna sequences were high, particularly within the nit ... | 2001 | 11760943 |
| gaseous no2 as a regulator for ammonia oxidation of nitrosomonas eutropha. | cells of nitrosomonas eutropha strain n904 that were denitrifying under anoxic conditions with hydrogen as electron donor and nitrite as electron acceptor were unable to utilize ammonium (ammonia) as an energy source. the recovery of ammonia oxidation activity was dependent on the presence of no2. anaerobic ammonia oxidation activity was observed in a helium atmosphere supplemented with 25 ppm no2 after 20 h. ammonia oxidation activity was detected after 2-3 days using an oxic atmosphere with 25 ... | 2001 | 11816974 |
| ammonia-oxidizing bacteria: a model for molecular microbial ecology. | the eutrophication of many ecosystems in recent decades has led to an increased interest in the ecology of nitrogen transformation. chemolitho-autotrophic ammonia-oxidizing bacteria are responsible for the rate-limiting step of nitrification in a wide variety of environments, making them important in the global cycling of nitrogen. these organisms are unique in their ability to use the conversion of ammonia to nitrite as their sole energy source. because of the importance of this functional grou ... | 2001 | 11544365 |
| quantification of nitrifying bacterial populations in a full-scale nitrifying trickling filter using fluorescent in situ hybridization. | fluorescent in situ hybridization (fish) was used to quantify the ammonia-oxidizing populations within intact biofilm samples collected from a full-scale nitrifying trickling filter (ntf). ammonia, nitrite, and nitrate concentrations were measured for aqueous samples taken in conjunction with biofilm samples at multiple filter depths. correlation coefficients for individual sampling events, calculated by simple linear regression of fish signal area and ammonia removal rates, ranged from 0.558 wh ... | 2001 | 11561593 |
| effect of zinc and benzalkonium chloride on nitrosomonas communis and potential nitrification in soil. | a bacterial contact assay is described which uses a chemoautotrophic microorganism, nitrosomonas communis (strain nm2) to evaluate the biological effect of contaminated soils. the effects of two toxicants on the ammonium oxidation activity of the autochthonous microbial population in the soil are compared with inhibition of the same biological response in the new monospecies bioassay. experiments were performed using soil samples dosed with organic and inorganic contaminants (benzalkonium chlori ... | 2001 | 11594031 |
| direct detection by in situ pcr of the amoa gene in biofilm resulting from a nitrogen removal process. | ammonia oxidation is a rate-limiting step in the biological removal of nitrogen from wastewater. analysis of microbial communities possessing the amoa gene, which is a small subunit of the gene encoding ammonia monooxygenase, is important for controlling nitrogen removal. in this study, the amoa gene present in nitrosomonas europaea cells in a pure culture and biofilms in a nitrifying reactor was amplified by in situ pcr. in this procedure, fixed cells were permeabilized with lysozyme and subjec ... | 2001 | 11679354 |
| crystal structure of nitrosomonas europaea cytochrome c peroxidase and the structural basis for ligand switching in bacterial di-heme peroxidases. | the crystal structure of the fully oxidized di-heme peroxidase from nitrosomonas europaea has been solved to a resolution of 1.80 a and compared to the closely related enzyme from pseudomonas aeruginosa. both enzymes catalyze the peroxide-dependent oxidation of a protein electron donor such as cytochrome c. electrons enter the enzyme through the high-potential heme followed by electron transfer to the low-potential heme, the site of peroxide activation. both enzymes form homodimers, each of whic ... | 2001 | 11695895 |
| potential nitrification rate as a tool for screening toxicity in metal-contaminated soils. | a potential nitrification rate test (pnr) was used to identify metal toxicity in field-contaminated soils. the test was applied to metal salt-spiked soils, to 27 uncontaminated soils, and to 15 soils that are contaminated by former metal smelting activities. four agricultural soils (ph 4.5-6.6) were spiked with various rates of cdcl2 (0-200 mg cd/kg dry wt) or zncl2 (0-3,000 mg cd/kg dry wt) and were equilibrated more than nine months prior to testing. the soil zn ec50s of the pnr were between 1 ... | 2001 | 11699771 |
| identification of bacteria responsible for ammonia oxidation in freshwater aquaria. | culture enrichments and culture-independent molecular methods were employed to identify and confirm the presence of novel ammonia-oxidizing bacteria (aob) in nitrifying freshwater aquaria. reactors were seeded with biomass from freshwater nitrifying systems and enriched for aob under various conditions of ammonia concentration. surveys of cloned rrna genes from the enrichments revealed four major strains of aob which were phylogenetically related to the nitrosomonas marina cluster, the nitrososp ... | 2001 | 11722936 |
| species diversity of uncultured and cultured populations of soil and marine ammonia oxidizing bacteria. | although molecular techniques are considered to provide a more comprehensive view of species diversity of natural microbial populations, few studies have compared diversity assessed by molecular and cultivation-based approaches using the same samples. to achieve this, the diversity of natural populations of ammonia oxidising bacteria in arable soil and marine sediments was determined by analysis of 16s rdna sequences from enrichment cultures, prepared using standard methods for this group, and f ... | 2001 | 12024248 |
| factors influencing spatial variability in nitrogen processing in nitrogen-saturated soils. | nitrogen (n) saturation is an environmental concern for forests in the eastern u.s. although several watersheds of the fernow experimental forest (fef), west virginia exhibit symptoms of n saturation, many watersheds display a high degree of spatial variability in soil n processing. this study examined the effects of temperature on net n mineralization and nitrification in n-saturated soils from fef, and how these effects varied between high n-processing vs. low n-processing soils collected from ... | 2001 | 12805879 |
| the canon system (completely autotrophic nitrogen-removal over nitrite) under ammonium limitation: interaction and competition between three groups of bacteria. | the canon system (completely autotrophic nitrogen removal over nitrite) can potentially remove ammonium from wastewater in a single, oxygen-limited treatment step. the usefulness of canon as an industrial process will be determined by the ability of the system to recover from major disturbances in feed composition. the canon process relies on the stable interaction between only two bacterial populations: nitrosomonas-like aerobic and planctomycete-like anaerobic ammonium oxidising bacteria. the ... | 2001 | 11876366 |
| purification and comparison of triosephosphate isomerases from ammonia-oxidizing bacteria isolated from terrestrial and marine environments. | triosephosphate isomerases [tims, ec 5.3.1.1] were purified from two ammonia-oxidizing bacteria: nitrosomonas sp. k1 (k1), nitrosomonas sp. tno632 (tno). the molecular masses of the native enzymes were estimated to be about 53.6 (k1-tim) and 51.9 kda (tno-tim) by gel filtration, whereas sds-page produced one band for each enzyme with m(r) values of 27.1 (k1-tim) and 26.4 kda (tno-tim), respectively, suggesting that the enzymes consist of identical subunits. the apparent k(m) for d-glyceraldehyde ... | 2001 | 16233048 |
| polyclonal antibodies recognizing the amob protein of ammonia oxidizers of the beta-subclass of the class proteobacteria. | a 41-kda protein of nitrosomonas eutropha was purified, and the n-terminal amino acid sequence was found to be nearly identical with the sequence of amob, a subunit of ammonia monooxygenase. this protein was used to develop polyclonal antibodies, which were highly specific for the detection of the four genera of ammonia oxidizers of the beta-subclass of proteobacteria (nitrosomonas, including nitrosococcus mobilis, which belongs phylogenetically to nitrosomonas; nitrosospira; nitrosolobus; and n ... | 2001 | 11133435 |
| energy model and metabolic flux analysis for autotrophic nitrifiers. | the behavior of pure cultures of nitrifying microorganisms under autotrophic growth operating conditions was investigated and the relations between their energy metabolism and their anabolism analyzed by means of metabolic network computation. the description of the metabolism of the nitrifiers is extended to their energy metabolism by introducing compartmentalization (cytoplasmic and periplasmic sides) and studying coupling between the electron transport chain and the proton gradient generation ... | 2001 | 11180062 |
| transcript analysis of multiple copies of amo (encoding ammonia monooxygenase) and hao (encoding hydroxylamine oxidoreductase) in nitrosomonas europaea. | the genes encoding ammonia monooxygenase (amocab), hydroxylamine oxidoreductase (hao), and the c-type cytochrome c-554 (hcy) are present in multiple copies in the genome of nitrosomonas europaea. the upstream regions of the two copies of amoc, the three copies of hao, and one copy of hcy were cloned and sequenced. primer extension reactions were done to identify transcription start sites for these genes, as well as for amoa. putative sigma(70) promoter sequences were found associated with all bu ... | 2001 | 11208810 |
| the evolutionary history of chromosomal super-integrons provides an ancestry for multiresistant integrons. | integrons are genetic elements that acquire and exchange exogenous dna, known as gene cassettes, by a site-specific recombination mechanism. characterized gene cassettes consist of a target recombination sequence (attc site) usually associated with a single open reading frame coding for an antibiotic resistance determinant. the affiliation of multiresistant integrons (mris), which contain various combinations of antibiotic resistance gene cassettes, with transferable elements underlies the rapid ... | 2001 | 11209061 |
| development of nitrification inhibition assays using pure cultures of nitrosomonas and nitrobacter. | restricted requirements for nitrogen reduction at wastewater treatment plants have increased the need for assays determining the inhibition of nitrification. in this paper, two new assays studying ammonia oxidation and nitrite oxidation, respectively, are presented. as test organisms, pure cultures of nitrosomonas and nitrobacter isolated from activated sludge are used. the assays are performed in test tubes where the bacteria are incubated with the compound or wastewater to be tested. the nitri ... | 2001 | 11228996 |
| community structure and activity dynamics of nitrifying bacteria in a phosphate-removing biofilm. | the microbial community structure and activity dynamics of a phosphate-removing biofilm from a sequencing batch biofilm reactor were investigated with special focus on the nitrifying community. o(2), no(2)(-), and no(3)(-) profiles in the biofilm were measured with microsensors at various times during the nonaerated-aerated reactor cycle. in the aeration period, nitrification was oxygen limited and restricted to the first 200 microm at the biofilm surface. additionally, a delayed onset of nitrif ... | 2001 | 11229931 |
| conversion of ammonia to dinitrogen in wastewater by nitrosomonas europaea. | because nitrosomonas europaea contains ammonia-oxidizing enzyme, nitrite reductase, and nitrous oxide reductase, the conversion of ammonia to dinitrogen was tried with different reaction conditions. in aerobic reaction conditions, ammonium was converted to nitrite (no2-), while under oxygen-limiting or oxygen-free conditions, no2(-)-n formed from ammonia oxidation by n. europaea was reduced to n2o and dinitrogen with 22% conversion. during denitrification, optimal ph for the production of n2o an ... | 2001 | 11318035 |
| dissimilatory nitrite reductase genes from autotrophic ammonia-oxidizing bacteria. | the presence of a copper-containing dissimilatory nitrite reductase gene (nirk) was discovered in several isolates of beta-subdivision ammonia-oxidizing bacteria using pcr and dna sequencing. pcr primers cunir3 and cunir4 were designed based on published nirk sequences from denitrifying bacteria and used to amplify a 540-bp fragment of the nirk gene from nitrosomonas marina and five additional isolates of ammonia-oxidizing bacteria. amplification products of the expected size were cloned and seq ... | 2001 | 11319103 |
| nitrification and denitrification as a source for no and no2 production in high-strength wastewater. | laboratory and half-technical scale experiments were performed to evaluate nitric oxide (no) and nitrogen dioxide (no2) production during biological n-elimination from wastewater with high ammonium concentration (about 700 mg n l-1). in a laboratory scale bioreactor with biomass retention, the ammonia oxidizer nitrosomonas europaea and the denitrifier paracoccus denitrificans were grown as reference organisms in co-culture in order to simulate the nitrifying and denitrifying community of wastewa ... | 2001 | 11337836 |
| nitrogen transformation during organic waste composting by the rutgers system and its effects on ph, ec and maturity of the composting mixtures. | the evolution of the different forms of nitrogen during the composting of several wastes was studied, as well as its relation to the ph, electrical conductivity and parameters of maturity of the composts obtained. four mixtures were prepared from different organic materials: sewage sludge, municipal solid waste, brewery sludge, sorghum bagasse, cotton waste and pine bark. the evolution of the different forms of nitrogen during composting depended on the material which supplied the nitrogen to th ... | 2001 | 11341692 |
| crystal structure of a novel red copper protein from nitrosomonas europaea. | nitrosocyanin (nc) is a mononuclear red copper protein isolated from the ammonia oxidizing bacterium nitrosomonas europaea. although nc exhibits some sequence homology to classic blue copper proteins, its spectroscopic and electrochemical properties are drastically different. the 1.65 a resolution crystal structure of oxidized nc reveals an unprecedented trimer of single domain cupredoxins. each copper center is partially covered by an unusual extended beta-hairpin structure from an adjacent mon ... | 2001 | 11341832 |
| high-resolution structures of the oxidized and reduced states of cytochrome c554 from nitrosomonas europaea. | cytochrome c554 (cyt c554) is a tetra-heme cytochrome involved in the oxidation of nh3 by nitrosomonas europaea. the x-ray crystal structures of both the oxidized and dithionite-reduced states of cyt c554 in a new, rhombohedral crystal form have been solved by molecular replacement, at 1.6 a and 1.8 a resolution, respectively. upon reduction, the conformation of the polypeptide chain changes between residues 175 and 179, which are adjacent to hemes iii and iv. cyt c554 displays conserved heme-pa ... | 2001 | 11372197 |
| toxic effects of linear alkylbenzene sulfonate on metabolic activity, growth rate, and microcolony formation of nitrosomonas and nitrosospira strains. | strong inhibitory effects of the anionic surfactant linear alkylbenzene sulfonate (las) on four strains of autotrophic ammonia-oxidizing bacteria (aob) are reported. two nitrosospira strains were considerably more sensitive to las than two nitrosomonas strains were. interestingly, the two nitrosospira strains showed a weak capacity to remove las from the medium. this could not be attributed to adsorption or any other known physical or chemical process, suggesting that biodegradation of las took ... | 2001 | 11375155 |
| implementation, study and calibration of a modified asm2d for the simulation of sbr processes. | an enhanced process model for sbrs has been developed. though the basic mechanism largely draws on the activated sludge model n. 2d, its new features are the splitting of the nitrification stage in a two-step process, according to the well known nitrosomonas-nitrobacter oxidation sequence, and an improved xpao dynamics, involved in the anaerobic/aerobic phosphorus removal process. the model was implemented through the dll technique allowing complied c++ modules to be linked to an ordinary simuli ... | 2001 | 11381934 |
| enhancement of nitrifying biofilm formation using selected eps produced by heterotrophic bacteria. | the possibility of enhancing nitrifying biofilm formation rate with the aid of selected eps produced by heterotrophic bacteria was investigated. when eps production characteristics were examined for four kinds of heterotrophs isolated from a domestic wastewater treatment reactor, two strains obtained from biofilms (b1, b2) exhibited a higher polysaccharide production rate than those from suspended flocs (a1, a2). among eps components, the concentration of uronic acids gave a good correlation wit ... | 2001 | 11381968 |
| effects of gaseous no2 on cells of nitrosomonas eutropha previously incapable of using ammonia as an energy source. | cells of nitrosomonas eutropha grown under anoxic conditions with hydrogen as electron donor and nitrite as electron acceptor were initially unable to oxidize ammonia (ammonium) and hydroxylamine when transferred to oxic conditions. recovery of ammonia and hydroxylamine oxidation activity was dependent on the presence of no2. under oxic conditions, without addition of no2, ammonia consumption started after 8 - 9 days, and small amounts of no and no2 were detectable in the gas atmosphere. removin ... | 2001 | 11392482 |
| in situ reverse transcription to detect the cbbl gene and visualize rubisco in chemoautotrophic nitrifying bacteria. | in situ methodologies targeting the cbbl gene were used to visualize cells of nitrifying bacteria. both procaryotic in situ pcr (is-pcr) and in situ reverse transcription (isrt) protocols were employed to determine gene presence and expression, respectively. | 2001 | 11412349 |
| (13)c incorporation into dna as a means of identifying the active components of ammonia-oxidizer populations. | to identify active co2-assimilating species of ammonia-oxidizing bacteria in fresh water sediment. | 2001 | 11412351 |
| soft particle analysis of bacterial cells and its interpretation of cell adhesion behaviors in terms of dlvo theory. | the electrokinetic properties of two nitrifying strains, nitrosomonas europaea and nitrobacter winogradskyi, and three heterotrophic bacteria, escherichia coli, pseudomonas putida and pseudomonas aeruginosa, were examined by electrophoretic mobility measurement and analyzed using the soft particle electrophoresis theory that is suitable for biological particles. the bacterial adhesion characteristics onto glass bead substratum were also evaluated by packed bed method. the mobility of the bacteri ... | 2001 | 11451661 |
| in situ analysis of nitrosomonas spp. in wastewater treatment wetland biofilms. | the presence of the ammonia-oxidising group nitrosomonas in developing biofilms from a subsurface flow dairy effluent treatment wetland was investigated using in situ hybridisation and a crude semi-quantitative pcr. fluorescently labelled oligonucleotide probes, specific for the nitrosomonas europaea and nitrosomonas eutropha species, showed that nitrifying bacteria were present from the onset of biofilm development but that over a five month period the proportions remained low (averaging less t ... | 2001 | 11456173 |
| correlations of structure and electronic properties from epr spectroscopy of hydroxylamine oxidoreductase. | hydroxylamine oxidoreductase (hao) from the autotrophic nitrifying bacterium nitrosomonas europaea catalyzes the oxidation of nh(2)oh to hno(2). the enzyme contains eight hemes per subunit which participate in catalytic function and electron transport. the structure of the enzyme shows a unique spatial arrangement of the eight hemes, subsets of which are now observed in four other proteins. the spatial arrangement displays three types of diheme pairing motifs. at least four of the eight hemes ar ... | 2001 | 11457010 |
| influence of effluent irrigation on community composition and function of ammonia-oxidizing bacteria in soil. | the effect of effluent irrigation on community composition and function of ammonia-oxidizing bacteria (aob) in soil was evaluated, using techniques of molecular biology and analytical soil chemistry. analyses were conducted on soil sampled from lysimeters and from a grapefruit orchard which had been irrigated with wastewater effluent or fertilizer-amended water (faw). specifically, comparisons of aob community composition were conducted using denaturing gradient gel electrophoresis (dgge) of pcr ... | 2001 | 11472914 |
| ammonia oxidation by nitrosomonas eutropha with no(2) as oxidant is not inhibited by acetylene. | the effect of acetylene ((14)c(2)h(2)) on aerobic and anaerobic ammonia oxidation by nitrosomonas eutropha was investigated. ammonia monooxygenase (amo) was inhibited and a 27 kda polypeptide (amoa) was labelled during aerobic ammonia oxidation. in contrast, anaerobic, no(2)-dependent ammonia oxidation (no(2)/n(2)o(4) as oxidant) was not affected by acetylene. further studies gave evidence that the inhibition as well as the labelling reaction were o(2)-dependent. cells pretreated with acetylene ... | 2001 | 11496001 |
| factors affecting nitrite build-up in nitrifying biofilm reactor. | nitrite build-up in a nitrifying biofilm reactor for direct denitrification from the nitrite stage was investigated. at least three factors were found to influence the nitrite build-up: (i) the relative specific growth rates of nitrosomonas to nitrobacter, microns/micronb in the biofilm; (ii) the relative initial ratio between nitrosomonas and nitrobacter on the support surface, (mao)ns/(mao)nb; (iii) the level of free ammonia, particularly at greater than 0.1 mg n/l that can be inhibitory to ni ... | 2001 | 11501303 |
| isolation and properties of obligately chemolithoautotrophic and extremely alkali-tolerant ammonia-oxidizing bacteria from mongolian soda lakes. | five mixed samples prepared from the surface sediments of 20 north-east mongolian soda lakes with total salt contents from 5 to 360 g/l and ph values from 9.7 to 10.5 were used to enrich for alkaliphilic ammonia-oxidizing bacteria. successful enrichments at ph 10 were achieved on carbonate mineral medium containing 0.6 m total na(+) and < or =4 mm nh(4)cl. five isolates (ans1-ans5) of ammonia-oxidizing bacteria capable of growth at ph 10 were obtained from the colonies developed on bilayered gra ... | 2001 | 11511864 |
| activity monitoring for nitrifying bacteria by fluorescence in situ hybridization and respirometry. | the activities of two families of nitrifying bacteria were measured by applied respirometer and fluorescence in situ hybridization (fish) for the purpose of monitoring nitrogen removal. oxygen uptake rates (our) for nitrosomonas and nitrobacter were separately measured with the dosing of selective inhibitors during respirometric monitoring. the fish method was applied to analyze microorganism communities. in 5 mg nh4+-n/l solution, the total nitrogen oxygen demand (nod) was found to be 6,672 mg ... | 2001 | 11516017 |
| inhibition of aerobic growth and nitrification of bacteria in sewage sludge by antibacterial agents. | toxicity of antibacterial agents on environmentally relevant bacteria was investigated using activated sludge. the growth and nitrifying inhibiting effects for activated sludge of benzyl penicillin (penicillin g) (bp), tetracycline (tc), chlortetracycline (ctc), oxytetracycline (otc), olaquindox (o), streptomycin (st), tiamulin (ti), tylosin (tyl) sulfadiazine (sdz), metronidazole (met), and oxolinic acid (oxa) was investigated. studies were performed in accordance to the iso 15522 (1999) and is ... | 2001 | 11525487 |
| differential inhibition in vivo of ammonia monooxygenase, soluble methane monooxygenase and membrane-associated methane monoxygenase by phenylacetylene. | phenylacetylene was investigated as a differential inhibitor of ammonia monooxygenase (amo), soluble methane monooxygenase (smmo) and membrane-associated or particulate methane monooxygenase (pmmo) in vivo. at phenylacetylene concentrations > 1 microm, whole-cell amo activity in nitrosomonas europaea was completely inhibited. phenylacetylene concentrations above 100 microm inhibited more than 90% of smmo activity in methylococcus capsulatus bath and methylosinus trichosporium ob3b. in contrast, ... | 2000 | 11233157 |
| nitrification inhibitors from the roots of leucaena leucocephala. | the nitrification inhibition (ni) bioassay guided fractionation of the methanol extract of lyophilized and milled roots of leuceana leucocephala resulted in the isolation of four compounds, 1-4, as confirmed from their 1h and 13c nmr spectral data. compound 1, gallocatechin, was the most active ni inhibitor at 12 microg/ml. epigallocatechin, 2, and epicatechin, 4, isolated as mixtures, were not assayed individually for their ni inhibitory activities against the nitrification bacterium nitrosomon ... | 2000 | 11312789 |
| microenvironments and distribution of nitrifying bacteria in a membrane-bound biofilm. | the distribution of nitrifying bacteria of the genera nitrosomonas, nitrosospira, nitrobacter and nitrospira was investigated in a membrane-bound biofilm system with opposed supply of oxygen and ammonium. gradients of oxygen, ph, nitrite and nitrate were determined by means of microsensors while the nitrifying populations along these gradients were identified and quantified using fluorescence in situ hybridization (fish) in combination with confocal laser scanning microscopy. the oxic part of th ... | 2000 | 11214800 |
| nitrogen removal reactor using packed gel envelopes containing nitrosomonas europaea and paracoccus denitrificans. | packed gel envelopes were constructed as simple, compact reactors for removing nitrogen from wastewater. each packed gel envelope consisted of two plate gels with a spacer in between. nitrosomonas europaea and paracoccus denitrificans were co-immobilized in the plate gels, and ethanol, serving as an electron donor for denitrification, was injected into the internal spaces of the envelopes. the external surfaces of the envelopes were in contact with ammonia-containing wastewater; the n. europaea ... | 2000 | 10581438 |
| physical map location of the multicopy genes coding for ammonia monooxygenase and hydroxylamine oxidoreductase in the ammonia-oxidizing bacterium nitrosomonas sp. strain eni-11. | pulsed-field gel electrophoresis of pmei digests of the nitrosomonas sp. strain eni-11 chromosome produced four bands ranging from 1,200 to 480 kb in size. southern hybridizations suggested that a 487-kb pmei fragment contained two copies of the amocab genes, coding for ammonia monooxygenase (designated amocab(1) and amocab(2)), and three copies of the hao gene, coding for hydroxylamine oxidoreductase (hao(1), hao(2), and hao(3)). in this dna fragment, amocab(1) and amocab(2) were about 390 kb a ... | 2000 | 10633121 |
| primary structure of cytochrome c' of methylococcus capsulatus bath: evidence of a phylogenetic link between p460 and c'-type cytochromes. | cytochrome c' of methylococcus capsulatus bath is involved in electron flow from the enzyme responsible for hydroxylamine oxidation, cytochrome p460, to cytochrome c555. this cytochrome is spectrally similar to other cytochromes c' but is larger (16,000 da) and has a lower midpoint potential (-205 mv). by a combination of edman degradation, mass spectroscopy, and gene sequencing, we have obtained the primary structure of cytochrome c' from m. capsulatus bath. the cytochrome shows low sequence si ... | 2000 | 10648101 |
| distribution of nitrosomonas europaea and paracoccus denitrificans immobilized in tubular polymeric gel for nitrogen removal. | to improve the cooperative removal of nitrogen by nitrosomonas europaea and paracoccus denitrificans, we controlled their distribution in a tubular gel. when ethanol was supplied inside the tubular gel as an electron donor, their distributions overlapped in the external region of the gel. by changing the electron donor from ethanol to gaseous hydrogen, the distribution of p. denitrificans shifted to the inside of the tube and was separated from that of n. europaea. the separation resulted in an ... | 2000 | 10653756 |
| identification of major subgroups of ammonia-oxidizing bacteria in environmental samples by t-rflp analysis of amoa pcr products. | a cloning-independent method based on t-rflp (terminal restriction fragment length polymorphism) analysis of amoa pcr products was developed to identify major subgroups of autotrophic ammonia oxidizers of the beta-subclass of the class proteobacteria in total community dna. based on a database of 28 partial gene sequences encoding the active-site polypeptide of ammonia monooxygenase (amoa), defined lengths of terminal restriction fragments (= operational taxonomic units, otus) of amoa were predi ... | 2000 | 10670766 |
| significance of gaseous no for ammonia oxidation by nitrosomonas eutropha. | nitrification by the obligately lithoautotrophic ammonia oxidizer nitrosomonas eutropha was significantly inhibited when nitric oxide was removed from the culture medium by means of intensive aeration and turbulence. nearly complete recovery of ammonia oxidation could be achieved by adding 100 ppm no to the supplied air. inhibition of ammonia oxidation occurred also upon addition of the no binding agent 2,3-dimercapto-1-propane-sulfonic acid (dmps). recovery of ammonia oxidation occurred within ... | 2000 | 10696878 |
| molecular analysis of ammonia-oxidising bacteria in soil of successional grasslands of the drentsche a (the netherlands). | changes in the community structure of chemolitho-autotrophic ammonia-oxidising bacteria of the beta-subgroup proteobacteria were monitored during nutrient-impoverishment management of slightly acidic, peaty grassland soils, which decreased in ph with succession. specific pcr, cloning and sequence analysis, denaturing gradient gel electrophoresis (dgge) and probe hybridisation were used to analyse rdna sequences directly recovered from successional soils. four previously characterised ammonia oxi ... | 2000 | 10719201 |
| analysis of ammonia-oxidizing bacteria populations in acid forest soil during conditions of moisture limitation. | ammonia-oxidizer numbers decreased under conditions of moisture limitation in litter, fermentation and humus layers of forest soil in the field, but the extent of regrowth after rehydration varied between layers. nitrosospira 16s rrna genes were amplified from all layers, regardless of moisture content or soil ph which varied between 4.1 and 5.2. nitrosomonas spp. were detected less often, but appeared to exhibit more rapid recovery than the nitrosospira spp. when drought conditions were relieve ... | 2000 | 10728553 |
| detection of groel in activated sludge: a model for detection of system stress. | groel is a ubiquitous constitutively synthesized protein that is also stress inducible. activated sludge, which is a standard biological process used in wastewater treatment systems, is made up of a diverse microbial consortium. the synthesis of groel in activated sludge was significantly induced after heat (42 degrees c) shock. the increased level of groel expression was shown to be due to de novo protein synthesis. we have demonstrated a method which shows that stress proteins can be detected ... | 2000 | 10728556 |
| nitrification inhibition by naphthalene derivatives and its relationship with copper. | 2000 | 10754051 | |
| diversity and distribution of dna sequences with affinity to ammonia-oxidizing bacteria of the beta subdivision of the class proteobacteria in the arctic ocean. | the spatial distribution and diversity of ammonia-oxidizing bacteria of the beta subdivision of the class proteobacteria (hereinafter referred to as ammonia oxidizers) in the arctic ocean were determined. the presence of ammonia oxidizers was detected by pcr amplification of 16s rrna genes using a primer set specific for this group of organisms (nita and nitb, which amplifies a 1.1-kb fragment between positions 137 and 1234, corresponding to escherichia coli 16s rdna numbering). we analyzed 246 ... | 2000 | 10788367 |
| involvement of a novel hydroxylamine oxidoreductase in anaerobic ammonium oxidation. | in this study a novel hydroxylamine oxidoreductase (hao) was purified and characterized from an anaerobic ammonium-oxidizing (anammox) enrichment culture. the enzyme, which constituted about 9% of the protein mass in the soluble fraction of the cell extract, was able to oxidize hydroxylamine and hydrazine. when phenazine methosulfate and methylthiazolyltetrazolium bromide were used as electron acceptors, a v(max) [21 and 1.1 micromol min(-)(1) (mg of protein)(-)(1)] and k(m) (26 and 18 microm) f ... | 2000 | 10820012 |
| effects of soil and water content on methyl bromide oxidation by the ammonia-oxidizing bacterium nitrosomonas europaea. | little information exists on the potential of nh(3)-oxidizing bacteria to cooxidize halogenated hydrocarbons in soil. a study was conducted to examine the cooxidation of methyl bromide (mebr) by an nh(3)-oxidizing bacterium, nitrosomonas europaea, under soil conditions. soil and its water content modified the availability of nh(4)(+) and mebr and influenced the relative rates of substrate (nh(3)) and cosubstrate (mebr) oxidations. these observations highlight the complexity associated with chara ... | 2000 | 10831449 |
| new insights into methyl bromide cooxidation by nitrosomonas europaea obtained by experimenting with moderately low density cell suspensions. | we examined the rates and sustainability of methyl bromide (mebr) oxidation in moderately low density cell suspensions ( approximately 6 x 10(7) cells ml(-1)) of the nh(3)-oxidizing bacterium nitrosomonas europaea. in the presence of 10 mm nh(4)(+) and 0.44, 0. 22, and 0.11 mm mebr, the initial rates of mebr oxidation were sustained for 12, 12, and 24 h, respectively, despite the fact that only 10% of the nh(4)(+), 18% of the nh(4)(+), and 35% of the nh(4)(+), respectively, were consumed. althou ... | 2000 | 10877761 |
| analysis of ammonia-oxidizing bacteria from hypersaline mono lake, california, on the basis of 16s rrna sequences. | ammonia-oxidizing bacteria were detected by pcr amplification of dna extracted from filtered water samples throughout the water column of mono lake, california. ammonia-oxidizing members of the beta subdivision of the division proteobacteria (beta-subdivision proteobacteria) were detected using previously characterized pcr primers; target sequences were detected by direct amplification in both surface water and below the chemocline. denaturing gradient gel electrophoresis analysis indicated the ... | 2000 | 10877781 |
| molecular evidence for genus level diversity of bacteria capable of catalyzing anaerobic ammonium oxidation. | recently, a bacterium capable to oxidize ammonium anaerobically at a high rate was identified as novel member of the planctomycetales (strous, m., fuersi, j. a., kramer, e. h. m., logemann, s., muyzer, g., van de pas-schoonen, k. t., webb, r. i., kufnen, j. g., and jetten, m. s. m.: nature 400, 446-449, 1999). here we investigated the microbial community structure of a trickling filter biofilm with a high anaerobic ammonium oxidation activity. fluorescence in situ hybridization (fish) with a set ... | 2000 | 10879983 |
| phylogenetic analysis of rhizosphere-associated beta-subclass proteobacterial ammonia oxidizers in a municipal wastewater treatment plant based on rhizoremediation technology. | in wastewater treatment plants based on the rhizosphere zone (rhizoremediation technology), ammonia-oxidizing bacteria (aob) play an important role in the removal of fixed nitrogen. however, the diversity of these bacteria in rhizoremediation wastewater treatment plants is largely unknown. we employed direct pcr amplification and cloning of 16s rrna genes to determine the phylogenetic affiliation of aob occurring in root and soil samples of a wastewater treatment plant (merzdorf plant, brandenbu ... | 2000 | 10886611 |
| mutational analysis of the multicopy hao gene coding for hydroxylamine oxidoreductase in nitrosomonas sp. strain eni-11. | the ammonia-oxidizing bacterium nitrosomonas sp. strain eni-11 contains three copies of the hao gene (hao1, hao2, and hao3) coding for hydroxylamine oxidoreductase (hao). three single mutants (hao1::kan, hao2::kan, or hao3::kan) had 68 to 75% of the wild-type growth rate and 58 to 89% of the wild-type hao activity when grown under the same conditions. a double mutant (hao1::kan and hao3::amp) also had 68% of the wild-type growth and 37% of the wild-type hao activity. | 2000 | 10993170 |
| electron transfer during the oxidation of ammonia by the chemolithotrophic bacterium nitrosomonas europaea. | the combined action of ammonia monooxygenase, amo, (nh(3)+2e(-)+o(2)-->nh(2)oh) and hydroxylamine oxidoreductase, hao, (nh(2)oh+h(2)o-->hno(2)+4e(-)+4h(+)) accounts for ammonia oxidation in nitrosomonas europaea. pathways for electrons from hao to o(2), nitrite, no, h(2)o(2) or amo are reviewed and some recent advances described. the membrane cytochrome c(m)552 is proposed to participate in the path between hao and ubiquinone. a bc(1) complex is shown to mediate between ubiquinol and the termina ... | 2000 | 11004450 |
| biotreatment of h2s- and nh3-containing waste gases by co-immobilized cells biofilter. | gas mixture of h2s and nh3 in this study has been the focus in the research area concerning gases generated from the animal husbandry and the anaerobic wastewater lagoons used for their treatment. a specific microflora (mixture of thiobacillus thioparus ch11 for h2s and nitrosomonas europaea for nh3) was immobilized with ca-alginate and packed inside a glass column to decompose h2s and nh3. the biofilter packed with co-immobilized cells was continuously supplied with h2s and nh3 gas mixtures of ... | 2000 | 11057594 |
| differential regulation of amoa and amob gene copies in nitrosomonas europaea. | nitrosomonas europaea contains two nearly identical copies of the operon, amocab, which encodes the ammonia monooxygenase (amo) enzyme. cells of n. europaea containing single mutations in either amoa or amob gene copies were incubated in ammonium both prior to and after exposure to acetylene or light. for each strain, the o(2) consumption rates and amounts of amoa polypeptide, the active site-containing subunit of amo, produced in each strain were determined. strains carrying a mutation in eithe ... | 2000 | 11064189 |
| phylogeny of all recognized species of ammonia oxidizers based on comparative 16s rrna and amoa sequence analysis: implications for molecular diversity surveys. | the current perception of evolutionary relationships and the natural diversity of ammonia-oxidizing bacteria (aob) is mainly based on comparative sequence analyses of their genes encoding the 16s rrna and the active site polypeptide of the ammonia monooxygenase (amoa). however, only partial 16s rrna sequences are available for many aob species and most aob have not yet been analyzed on the amoa level. in this study, the 16s rdna sequence data of 10 nitrosomonas species and nitrosococcus mobilis ... | 2000 | 11097916 |
| effects of agronomic treatments on structure and function of ammonia-oxidizing communities. | the aim of this study was to determine the effects of different agricultural treatments and plant communities on the diversity of ammonia oxidizer populations in soil. denaturing gradient gel electrophoresis (dgge), coupled with specific oligonucleotide probing, was used to analyze 16s rrna genes of ammonia oxidizers belonging to the beta subgroup of the division proteobacteria by use of dna extracted from cultivated, successional, and native deciduous forest soils. community profiles of the dif ... | 2000 | 11097922 |