Publications

bacterial diversity in water samples from uranium wastes as demonstrated by 16s rdna and ribosomal intergenic spacer amplification retrievals.	bacterial diversity was assessed in water samples collected from several uranium mining wastes in ger many and in the united states by using 16s rdna and ribosomal intergenic spacer amplification retrievals. the results obtained using the 16s rdna retrieval showed that the samples collected from the uranium mill tailings of schlema/alberoda, germany, were predominated by nitrospina-like bacteria, whereas those from the mill tailings of shiprock, new mexico, usa, were predominated by gamma-pseudo ...	2005	16333330
primers containing universal bases reduce multiple amoa gene specific dgge band patterns when analysing the diversity of beta-ammonia oxidizers in the environment.	the gene encoding the active site of the ammonia monooxygenase (amoa) has been exploited as molecular marker for studying ammonia-oxidizing bacteria (aob) diversity in the environment. primers amplifying functional genes are often degenerated and therefore produce multiple band patterns, when analysed with the denaturing gradient gel electrophoresis (dgge) approach. to improve the dgge band patterns we have designed new primer sets which contain inosine residues and are specific for the amoa gen ...	2006	16343671
diversity in the ammonia-oxidizing nitrifier population of a soil.	multiple genera of ammonia-oxidizing chemoautotrophic nitrifiers in a soil were detected, isolated, and studied by means of modified most-probable-number (mpn) techniques. the soil examined was a waukegon silt loam treated with ammonium nitrate or sewage effluent. the genera nitrosomonas and nitrosospira were found to occur more commonly than the genus nitrosolobus. three different mpn media gave approximately the same overall ammonia oxidizer counts within statistical error after prolonged incu ...	1978	16345319
serological diversity within a terrestrial ammonia-oxidizing population.	fluorescent antibodies (fas) prepared against 16 ammonia-oxidizing nitrifying bacteria were examined as to cross-reactivity in heterologous fa staining tests. virtually all cross-reactions to the seven nitrosomonas fas were confined to the nitrosomonas isolates. the five nitrosospira, three nitrosolobus, and one nitrosovibrio fas stained isolates only within their respective genera. within each genus shared antigens were more common among nitrosomonas and nitrosolobus than among nitrosospira iso ...	1978	16345320
production of no(2) and n(2)o by nitrifying bacteria at reduced concentrations of oxygen.	pure cultures of the marine ammonium-oxidizing bacterium nitrosomonas sp. were grown in the laboratory at oxygen partial pressures between 0.005 and 0.2 atm (0.18 to 7 mg/liter). low oxygen conditions induced a marked decrease in the rate for production of no(2), from 3.6 x 10 to 0.5 x 10 mmol of no(2) per cell per day. in contrast, evolution of n(2)o increased from 1 x 10 to 4.3 x 10 mmol of n per cell per day. the yield of n(2)o relative to no(2) increased from 0.3% to nearly 10% (moles of n i ...	1980	16345632
production of nitrous oxide by ammonia-oxidizing chemoautotrophic microorganisms in soil.	gas chromatographic studies showed that nitrous oxide was produced in each instance when sterilized (autoclaved) soil was incubated after treatment with ammonium sulfate and inoculation with pure cultures of ammonia-oxidizing chemoautotrophic microorganisms (strains of nitrosomonas, nitrosospira, and nitrosolobus). production of n(2)o in ammonium-treated sterilized soil inoculated with nitrosomonas europaea increased with the concentration of ammonium and the moisture content of the soil and was ...	1980	16345670
inhibitory effect of nitrapyrin on three genera of ammonia-oxidizing nitrifiers.	five strains of nitrosomonas and one each of nitrosospira and nitrosolobus were examined for sensitivity to the nitrification inhibitor nitrapyrin. considerable variation in sensitivity was observed, with some strains about five times more resistant than others. sensitivity to nitrapyrin varied more with strain than with genus.	1981	16345741
stimulation of autotrophic ammonium oxidation in rice rhizosphere soil by the insecticide carbofuran.	the application of the insecticide carbofuran (technical or formulated) to rice rhizosphere soil suspensions at 10 and 100 ppm (mug/ml) of active ingredient distinctly stimulated the autotrophic oxidation of ammonium. evidence suggested that nitrosomonas sp. was enriched in the presence of carbofuran. formulated carbofuran (furadan 3g) exhibited a more pronounced stimulation of ammonium oxidation than that exhibited by technical-grade (99.5%) carbofuran, a result which was attributed to the caco ...	1982	16346046
methane oxidation by nitrosococcus oceanus and nitrosomonas europaea.	chemolithotrophic ammonium-oxidizing and nitrite-oxidizing bacteria including nitrosomonas europaea, nitrosococcus oceanus, nitrobacter sp., nitiospina gracilis, and nitrococcus mobilis were examined as to their ability to oxidize methane in the absence of ammonium or nitrite. all ammonium oxidizers tested had the ability to oxidize significant amounts of methane to co(2) and incorporate various amounts into cellular components. none of the nitrite-oxidizing bacteria were capable of methane oxid ...	1983	16346190
population ecology of nitrifiers in a stream receiving geothermal inputs of ammonium.	the distribution, activity, and generic diversity of nitrifying bacteria in a stream receiving geothermal inputs of ammonium were studied. the high estimated rates of benthic nitrate flux (33 to 75 mg of n . m . h) were a result of the activity of nitrifiers located in the sediment. nitrifying potentials and ammonium oxidizer most probable numbers in the sediments were at least one order of magnitude higher than those in the waters. nitrifiers in the oxygenated surface (0 to 2 cm) sediments were ...	1983	16346261
inhibition of chemoautotrophic nitrification by sodium chlorate and sodium chlorite: a reexamination.	the oxidation of nh(4) by nitrosomonas europaea was insensitive to 10 mm naclo(3) (sodium chlorate) but was strongly inhibited by naclo(2) (sodium chlorite; k(i), 2 mum). the oxidation of no(2) by nitrobacter winogradskyi was inhibited by both clo(3) and clo(2) (k(i) for clo(2), 100 mum). n. winogradskyi reduced clo(3) to clo(2) under both aerobic and anaerobic conditions, and as much as 0.25 mm clo(2) was detected in the culture filtrate. in mixed n. europaea-n. winogradskyi cell suspensions, t ...	1983	16346262
bicarbonate uptake by nitrifiers: effects of growth rate, ph, substrate concentration, and metabolic inhibitors.	the ratios of bicarbonate uptake to substrate oxidation were measured for three genera of nitrifying bacteria. the ratios for the two ammonium oxidizers tested were essentially the same; 0.0863 +/- 0.0055 and 0.0868 +/- 0.0091 mumol of bicarbonate were taken up per umol ammonium oxidized for nitrosomonas europaea and a nitrosospira strain, respectively. for nitrobacter sp., a ratio of 0.0236 +/- 0.0013 mumol of bicarbonate taken up per umol of nitrite oxidized was obtained. cells were grown in s ...	1984	16346673
test medium for the growth of nitrosomonas europaea.	a mineral medium for studying the growth of nitrosomonas europaea was developed and examined. the medium was defined in terms of chemical speciation by using chemical equilibrium computer models. the medium significantly increased the metabolic activity of the organisms compared with previously developed media, yielding a specific growth rate as high as 3.0 day (generation time, 5.5 h). the specific growth rate was enhanced by increasing the inoculum and was linearly correlated with the inoculum ...	1985	16346783
n kinetic analysis of n(2)o production by nitrosomonas europaea: an examination of nitrifier denitrification.	a series of n isotope tracer experiments showed that nitrosomonas europaea produces nitrous oxide only under oxygen-limiting conditions and that the labeled n from nitrite, but not nitrate, is incorporated into nitrous oxide, indicating the presence of the "denitrifying enzyme" nitrite reductase. a kinetic analysis of the m/z 44, 45, and 46 nitrous oxide produced by washed cell suspensions of n. europaea when incubated with 4 mm ammonium (99% n) and 0.4 mm nitrite (99% n) was performed. no label ...	1985	16346787
inhibition of ammonium oxidation by nitrapyrin in soil and liquid culture.	inhibition of growth of axenic cultures of nitrosomonas europaea by nitrapyrin was investigated in liquid culture and in soil. in liquid culture, exponentially growing cells were more sensitive than stationary-phase cells, possibly due to a requirement for uptake of nitrapyrin, metabolism of nitrapyrin, or both before inhibition. differences in sensitivity were observed between the parent strain and two strains, sp1 and sp2, that were selected through repeated subculturing. these differences wer ...	1986	16347171
dinitrogen production from nitrite by a nitrosomonas isolate.	a chemolithotrophic ammonium-oxidizing bacterium that was able to reduce no(2) to n(2) (m/z 30) while oxidizing ammonium under conditions of oxygen stress was isolated from stream sediments. energy was derived from ammonium oxidation, as evidence by growth, with co(2) serving as the sole c source. the organism was a gram-negative, motile, short rod that failed to grow either aerobically or anaerobically in heterotroph media. the organism was identified as a nitrosomonas sp.	1986	16347192
nitrifying bacteria in wastewater reservoirs.	deep wastewater reservoirs are used throughout israel to store domestic wastewater effluents for summer irrigation. these effluents contain high concentrations of ammonia (</=5 mm) that are frequently toxic to photosynthetic microorganisms and that lead to development of anoxic conditions. population dynamics of nitrifying bacteria and rates of nitrification were studied in two wastewater reservoirs that differed in organic load and degree of oxygenation and in the laboratory under controlled co ...	1987	16347319
effects of light and co on the survival of a marine ammonium-oxidizing bacterium during energy source deprivation.	the chemolithotrophic ammonium-oxidizing bacterium nitrosomonas cryotolerans responds uniquely to nutrient deprivation by lowering its endogenous respiration and anabolic processes to undetectable levels during starvation, thus appearing to enter a dormant state. to ascertain whether this state protects the cells from further stresses (as seen with endospore-forming bacteria), the starved cells were subjected to two known inhibitors, co and light. it was found that long-term-starved cells were l ...	1988	16347787
interaction of ammonia monooxygenase from nitrosomonas europaea with alkanes, alkenes, and alkynes.	ammonia monooxygenase of nitrosomonas europaea catalyzes the oxidation of alkanes (up to c(8)) to alcohols and alkenes (up to c(5)) to epoxides and alcohols in the presence of ammonium ions. straight-chain, n-terminal alkynes (up to c(10)) all exhibited a time-dependent inhibition of ammonia oxidation without effects on hydrazine oxidation.	1988	16347810
nitrosovibrio spp., the dominant ammonia-oxidizing bacteria in building sandstone.	in five historical buildings in the federal republic of germany, ammonia-oxidizing bacteria of the genera nitrosovibrio, nitrosospira, and nitrosomonas were detected in high cell numbers. in building stones, nitrosovibrio was the most abundant ammonia-oxidizing organism. in the soil at the foot of each building, nitrosomonas spp. were the most common ammonia oxidizers, whereas nitrosovibrio spp. were not detected.	1989	16348002
biodegradation of halogenated hydrocarbon fumigants by nitrifying bacteria.	three species of nitrifying bacteria were tested for the ability to degrade the halocarbon fumigants methyl bromide, 1,2-dichloropropane, and 1,2-dibromo-3-chloropropane. the soil nitrifiers nitrosomonas europaea and nitrosolobus multiformis degraded all three fumigants, while the marine nitrifier nitrosococcus oceanus degraded only methyl bromide under the conditions tested. inhibition of biodegradation by allylthiourea and acetylene, specific inhibitors of ammonia monooxygenase, suggests that ...	1990	16348264
factors limiting aliphatic chlorocarbon degradation by nitrosomonas europaea: cometabolic inactivation of ammonia monooxygenase and substrate specificity.	the soil nitrifying bacterium nitrosomonas europaea is capable of degrading trichloroethylene (tce) and other halogenated hydrocarbons. tce cometabolism by n. europaea resulted in an irreversible loss of tce biodegradative capacity, ammonia-oxidizing activity, and ammonia-dependent o(2) uptake by the cells. inactivation was not observed in the presence of allylthiourea, a specific inhibitor of the enzyme ammonia monooxygenase, or under anaerobic conditions, indicating that the tce-mediated inact ...	1991	16348568
competition for ammonium between nitrifying and heterotrophic bacteria in dual energy-limited chemostats.	the absence of nitrification in soils rich in organic matter has often been reported. therefore, competition for limiting amounts of ammonium between the chemolithotrophic ammonium-oxidizing species nitrosomonas europaea and the heterotrophic species arthrobacter globiformis was studied in the presence of nitrobacter winogradskyi in continuous cultures at dilution rates of 0.004 and 0.01 h. ammonium limitation of a. globiformis was achieved by increasing the glucose concentration in the reservoi ...	1991	16348588
effects of grazing by flagellates on competition for ammonium between nitrifying and heterotrophic bacteria in chemostats.	the enhanced mineralization of organic nitrogen by bacteriophagous protozoa is thought to favor the nitrification process in soils, in which nitrifying bacteria have to compete with heterotrophic bacteria for the available ammonium. to obtain more insight into this process, the influence of grazing by the bacteriovorous flagellate adriamonas peritocrescens on the competition for limiting amounts of ammonium between the ammonium-oxidizing species nitrosomonas europaea and the heterotrophic specie ...	1992	16348722
oxidation of nitrapyrin to 6-chloropicolinic acid by the ammonia-oxidizing bacterium nitrosomonas europaea.	suspensions of nitrosomonas europaea catalyzed the oxidation of the commercial nitrification inhibitor nitrapyrin [2-chloro-6-(trichloromethyl)-pyridine]. rapid oxidation of nitrapyrin (at a concentration of 10 mum) required the concomitant oxidation of ammonia, hydroxylamine, or hydrazine. the turnover rate was highest in the presence of 10 mm ammonia (0.8 nmol of nitrapyrin per min/mg of protein). the product of the reaction was 6-chloropicolinic acid. by the use of o(2), it was shown that one ...	1992	16348740
competition for ammonium between nitrifying and heterotrophic bacteria in continuously percolated soil columns.	although the absence of nitrate formation in grassland soils rich in organic matter has often been reported, low numbers of nitrifying bacteria are still found in these soils. to obtain more insight into these observations, we studied the competition for limiting amounts of ammonium between the chemolithotrophic ammonium-oxidizing species nitrosomonas europaea and the heterotrophic species arthrobacter globiformis in the presence of nitrobacter winogradskyi with soil columns containing calcareou ...	1992	16348787
quantitative determination of the spatial distribution of nitrosomonas europaea and nitrobacter agilis cells immobilized in kappa-carrageenan gel beads by a specific fluorescent-antibody labelling technique.	a novel technique, combining labelling and stereological methods, for the determination of spatial distribution of two microorganisms in a biofilm is presented. cells of nitrosomonas europaea (atcc 19718) and nitrobacter agilis (atcc 14123) were homogeneously distributed in a kappa-carrageenan gel during immobilization and allowed to grow out to colonies. the gel beads were sliced in thin cross sections after fixation and embedding. a two-step labelling method resulted in green fluorescent colon ...	1993	16348970
effects of grazing by flagellates on competition for ammonium between nitrifying and heterotrophic bacteria in soil columns.	the enhanced mineralization of immobilized nitrogen by bacteriophagous protozoa has been thought to favor the nitrification process in soils in which nitrifying bacteria must compete with heterotrophic bacteria for the available ammonium. to obtain more insight into this process, the influence of grazing by the flagellate adriamonas peritocrescens on the competition for ammonium between the chemolithotrophic species nitrosomonas europaea and the heterotrophic species arthrobacter globiformis in ...	1993	16348988
selective inhibition of ammonium oxidation and nitrification-linked n(2)o formation by methyl fluoride and dimethyl ether.	methyl fluoride (ch(3)f) and dimethyl ether (dme) inhibited nitrification in washed-cell suspensions of nitrosomonas europaea and in a variety of oxygenated soils and sediments. headspace additions of ch(3)f (10% [vol/vol]) and dme (25% [vol/vol]) fully inhibited no(2) and n(2)o production from nh(4) in incubations of n. europaea, while lower concentrations of these gases resulted in partial inhibition. oxidation of hydroxylamine (nh(2)oh) by n. europaea and oxidation of no(2) by a nitrobacter s ...	1993	16349011
kinetic studies of ammonia monooxygenase inhibition in nitrosomonas europaea by hydrocarbons and halogenated hydrocarbons in an optimized whole-cell assay.	the inhibitory effects of 15 hydrocarbons and halogenated hydrocarbons on nh(3) oxidation by ammonia monooxygenase (amo) in intact cells of the nitrifying bacterium nitrosomonas europaea were determined. determination of amo activity, measured as no(2) production, required coupling of hydroxylamine oxidoreductase (hao) activity with nh(3)-dependent nh(2)oh production by amo. hydrazine, an alternate substrate for hao, was added to the reaction mixtures as a source of reductant for amo. most inhib ...	1993	16349014
inhibition of ammonia oxidation in nitrosomonas europaea by sulfur compounds: thioethers are oxidized to sulfoxides by ammonia monooxygenase.	organic sulfur compounds are well-known nitrification inhibitors. the inhibitory effects of dimethylsulfide, dimethyldisulfide, and ethanethiol on ammonia oxidation by nitrosomonas europaea were examined. both dimethylsulfide and dimethyldisulfide were weak inhibitors of ammonia oxidation and exhibited inhibitory characteristics typical of substrates for ammonia monooxygenase (amo). depletion of dimethylsulfide required o(2) and was prevented with either acetylene or allylthiourea, two inhibitor ...	1993	16349086
mechanism-based inactivation of ammonia monooxygenase in nitrosomonas europaea by allylsulfide.	allylsulfide caused an irreversible inactivation of ammonia monooxygenase (amo) activity (ammonia-dependent o(2) uptake) in nitrosomonas europaea. the hydroxylamine oxidoreductase activity (hydrazine-dependent o(2) uptake) of cells was unaffected by allylsulfide. anaerobic conditions or the presence of allylthiourea, a reversible noncompetitive amo inhibitor, protected amo from inactivation by allylsulfide. ammonia did not protect amo from inactivation by allylsulfide but instead increased the r ...	1993	16349087
transformations of aromatic compounds by nitrosomonas europaea.	benzene and a variety of substituted benzenes inhibited ammonia oxidation by intact cells of nitrosomonas europaea. in most cases, the inhibition was accompanied by transformation of the aromatic compound to a more oxidized product or products. all products detected were aromatic, and substituents were often oxidized but were not separated from the benzene ring. most transformations were enhanced by (nh(4))(2)so(4) (12.5 mm) and were prevented by c(2)h(2), a mechanism-based inactivator of ammoni ...	1994	16349282
enzyme immunoassay detection of nitrosomonas europaea.	an exploratory effort to selectively detect the presence of a nitrifying bacterium, nitrosomonas europaea, successfully demonstrated the fundamental utility of an enzyme-based immunoassay protocol. the applied polyclonal antibody test seemingly offered a marked improvement over the available analytical options, including plating, activity, and fluorescence immunoassay techniques. following an initial purification step to enhance overall specificity, this procedure had an apparent lower limit of ...	1994	16349287
effects of soil on ammonia, ethylene, chloroethane, and 1,1,1-trichloroethane oxidation by nitrosomonas europaea.	ammonia monooxygenase (amo) from nitrosomonas europaea catalyzes the oxidation of ammonia to hydroxylamine and has been shown to oxidize a variety of halogenated and nonhalogenated hydrocarbons. as part of a program focused upon extending these observations to natural systems, a study was conducted to examine the influence of soil upon the cooxidative abilities of n. europaea. small quantities of willamette silt loam (organic carbon content, 1.8%; cation-exchange capacity, 15 cmol/kg of soil) we ...	1998	16349541
ammonium limitation results in the loss of ammonia-oxidizing activity in nitrosomonas europaea.	the effects of limiting concentrations of ammonium on the metabolic activity of nitrosomonas europaea, an obligate ammonia-oxidizing soil bacterium, were investigated. cells were harvested during late logarithmic growth and were incubated for 24 h in growth medium containing 0, 15, or 50 mm ammonium. the changes in nitrite production and the rates of ammonia- and hydroxylamine-dependent oxygen consumption were monitored. in incubations without ammonium, there was little change in the ammonia oxi ...	1998	16349550
reliable procedure for silica gel preparation.	a simple and reliable method is described for preparation of silica gel media for nitrosomonas and nitrobacter species.	1972	16349945
disruption of suca, which encodes the e1 subunit of alpha-ketoglutarate dehydrogenase, affects the survival of nitrosomonas europaea in stationary phase.	although nitrosomonas europaea lacks measurable alpha-ketoglutarate dehydrogenase activity, the recent completion of the genome sequence revealed the presence of the genes encoding the enzyme. a knockout mutation was created in the suca gene encoding the e1 subunit. compared to wild-type cells, the mutant strain showed an accelerated loss of ammonia monooxygenase and hydroxylamine oxidoreductase activities upon entering stationary phase. in addition, unlike wild-type cells, the mutant strain sho ...	2006	16352852
calcium carbonate phosphate binding ion exchange filtration and accelerated denitrification improve public health standards and combat eutrophication in aquatic ecosystems.	cultural eutrophication, the process by which a lake becomes rich in dissolved nutrients as a result of point and nonpoint pollutant sources, is a major cause of the loss of natural lake ecosystems throughout the world. the process occurs naturally in all lakes, but phosphate-rich nutrient runoff from sources such as storm drains and agricultural runoff is a major cause of excess phosphate-induced eutrophication. especially in madrona marsh, one of the last remaining vernal marshes in the greate ...	2005	16381147
distinguishing nitrous oxide production from nitrification and denitrification on the basis of isotopomer abundances.	the intramolecular distribution of nitrogen isotopes in n2o is an emerging tool for defining the relative importance of microbial sources of this greenhouse gas. the application of intramolecular isotopic distributions to evaluate the origins of n2o, however, requires a foundation in laboratory experiments in which individual production pathways can be isolated. here we evaluate the site preferences of n2o produced during hydroxylamine oxidation by ammonia oxidizers and by a methanotroph, ammoni ...	2006	16391101
tgge analysis of the diversity of ammonia-oxidizing and denitrifying bacteria in submerged filter biofilms for the treatment of urban wastewater.	the spatial and temporal diversity of the bacterial community-forming biofilms in a pilot-scale submerged biofilter used for the treatment of urban wastewater was analyzed by a temperature-gradient gel electrophoresis (tgge) approach. tgge profiles based on partial sequence of the 16s rrna gene showed that the community composition of the biofilms remained fairly stable along the column system and during the whole time of operation of the biofilter (more than 1 year). community-profiling based o ...	2006	16391923
immunocytochemical localization of membrane-bound ammonia monooxygenase in cells of ammonia oxidizing bacteria.	the intracellular location of the membrane-bound ammonia monooxygenase (amo) in all genera of ammonia oxidizing bacteria (nitrosomonas, nitrosococcus and nitrosospira) was determined by electron microscopic immunocytochemistry. polyclonal antibodies recognizing the two subunits, amoa- and amob-proteins, were used for post-embedding labeling. ultrathin sections revealed that the amob-protein was located in all genera on the cytoplasmic membrane. in cells of nitrosomonas and nitrosococus additiona ...	2006	16395553
role of nitrogen oxides in the metabolism of ammonia-oxidizing bacteria.	ammonia-oxidizing bacteria (aob) can use oxygen and nitrite as electron acceptors. nitrite reduction by nitrosomonas is observed under three conditions: (i) hydrogen-dependent denitrification, (ii) anoxic ammonia oxidation with nitrogen dioxide (no(2)) and (iii) no(x)-induced aerobic ammonia oxidation. no(x) molecules play an important role in the conversion of ammonia and nitrite by aob. absence of nitric oxide (no), which is generally detectable during ammonia oxidation, severely impairs ammon ...	2006	16417515
nitrosospira spp. can produce nitrous oxide via a nitrifier denitrification pathway.	nitrous oxide (n(2)o) emission from soils is a major contributor to the atmospheric loading of this potent greenhouse gas. it is thought that autotrophic ammonia oxidizing bacteria (aob) are a significant source of soil-derived n(2)o and a denitrification pathway (i.e. reduction of no(2) (-) to no and n(2)o), so-called nitrifier denitrification, has been demonstrated as a n(2)o production mechanism in nitrosomonas europaea. it is thought that nitrosospira spp. are the dominant aob in soil, but l ...	2006	16423010
the yjeb (nsrr) gene of escherichia coli encodes a nitric oxide-sensitive transcriptional regulator.	microarray studies of the escherichia coli response to nitric oxide and nitrosative stress have suggested that additional transcriptional regulators of this response remain to be characterized. we identify here the product of the yjeb gene as a negative regulator of the transcription of the ytfe, hmpa and ygba genes, all of which are known to be upregulated by nitrosative stress. transcriptional fusions to the promoters of these genes were expressed constitutively in a yjeb mutant, indicating th ...	2006	16428390
pilot-scale studies on biological treatment of hypersaline wastewater at low temperature.	in order to investigate the feasibility of biological treatment of hypersaline wastewater produced from toilet flushing with seawater at low temperature, pilot-scale studies were established with plug-flow activated sludge process at low temperature (5-9 degrees c) based on bench-scale experiments. the critical salinity concentration of 30 g/l, which resulted from the cooperation results of the non-halophilic bacteria and the halophilic bacteria, was drawn in bench-scale experiments. pilot-scale ...	2005	16459784
long-term monitoring of the succession of a microbial community in activated sludge from a circulation flush toilet as a closed system.	the microbial diversity and community succession of a circulation flush toilet were investigated by terminal restriction fragment length polymorphism and cloning analyses. clonal libraries of 16s rrna gene on day 3 and day 127 were constructed. on day 3, 102 clones were sequenced; proteobacteria and bacteroidetes accounted for 27% and 45%, respectively. on day 127, proteobacteria had increased to 43% and bacteroidetes had decreased to 26% of a total of 100 clones. terminal restriction fragment l ...	2006	16466385
kinetic analysis of the inhibitory effect of trichloroethylene (tce) on nitrification in cometabolic degradation.	in this study, the inhibitory effect of tce on nitrification process was investigated with an enriched nitrifier culture. tce was found to be a competitive inhibitor of ammonia oxidation and the inhibition constant (k(i)) was determined as 666-802 microg/l. the tce affinity for the amo enzyme was significantly higher than ammonium. the effect of tce on ammonium utilization was evaluated with linearized plots of monod equation (e.g., lineweaver-burk, hanes-woolf and eadie-hofstee plots) and non-l ...	2007	16467966
community structures and activities of nitrifying and denitrifying bacteria in industrial wastewater-treating biofilms.	the bacterial community structure, in situ spatial distributions and activities of nitrifying and denitrifying bacteria in biofilms treating industrial wastewater were investigated by combination of the 16s rrna gene clone analysis, fluorescence in situ hybridization (fish) and microelectrodes. these results were compared with the nitrogen removal capacity of the industrial wastewater treatment plant (iwtp). both nitrification and denitrification occurred in the primary denitrification (pd) tank ...	2006	16477661
classification of proteins based on minimal modular repeats: lessons from nature in protein design.	proteins containing internal repeats within their primary sequence have received increased attention recently, as the extent of their presence in various organisms is recognized more fully, and their role in evolution is more thoroughly studied. presented here is a technique used to detect and classify proteins based on a modular evolutionary phenomenon that results in a series of small internal repeats. the parameters chosen are based on a minimum segment of seven residues that result in simple ...	2006	16512661
molecular microbial diversity of a soil sample and detection of ammonia oxidizers from cape evans, mcmurdo dry valley, antarctica.	the aim of our study was to estimate the uncultured eubacterial diversity of a soil sample collected below a dead seal, cape evans, mcmurdo, antarctica by an ssu rdna gene library approach. our study by sequencing of clones from ssu rdna gene library approach revealed high diversity in the soil sample from antarctica. more than 50% of clones showed homology to cytophaga-flavobacterium-bacteroides group; sequences also belonged to alpha, beta, gamma proteobacteria, thermus-deinococcus and high gc ...	2007	16517136
development and application of real-time pcr for quantification of specific ammonia-oxidizing bacteria in activated sludge of sewage treatment systems.	in this study, four real-time polymerase chain reaction (pcr) primer sets were developed for the 16s rrna genes of specific ammonia-oxidizing bacteria (aob) found in activated sludge of sewage treatment systems. the primer sets target two of several sequence types of the nitrosomonas oligotropha cluster, members within the nitrosomonas communis cluster, and all members of the nitrosomonas europaea-nitrosococcus mobilis cluster. the detection limit of each primer set was in the range of 3x10(1)-6 ...	2006	16523283
long term effects of salt on activity, population structure and floc characteristics in enriched bacterial cultures of nitrifiers.	the effect of salinity on the activity, the composition of nitrifiers and floc characteristics of nitrifying sludge was studied. non-adapted and adapted (to 10g nacl-cl(-)/l for one year) enriched cultures of nitrifiers were tested in three sequencing batch reactors. salt was increased gradually with 5 up to 40 g cl(-)/l. no difference in steady state activity was observed between the adapted and non-adapted sludge. the activities of ammonia and nitrite oxidizers dropped 36% and 11%, respectivel ...	2006	16530803
inhibition, inactivation, and recovery of ammonia-oxidizing activity in cometabolism of trichloroethylene by nitrosomonas europaea.	the kinetics of the cometabolism of trichloroethylene (tce) by the ammonia-oxidizing soil bacterium nitrosomonas europaea in short-term (<10-min) incubations were investigated. three individual effects of tce cometabolism on this bacterium were characterized. first, we observed that tce is a potent competitive inhibitor of ammonia oxidation by n. europaea. the k(infi) value for tce (30 (mu)m) is similar to the k(infm) for ammonia (40 (mu)m). second, we examined the toxicity associated with tce c ...	1995	16534997
production of no and n(inf2)o by pure cultures of nitrifying and denitrifying bacteria during changes in aeration.	peak emissions of no and n(inf2)o are often observed after wetting of soil. the reactions to sudden changes in the aeration of cultures of nitrifying and denitrifying bacteria with respect to no and n(inf2)o emissions were compared to obtain more information about the microbiological aspects of peak emissions. in continuous culture, the nitrifier nitrosomonas europaea and the denitrifiers alcaligenes eutrophus and pseudomonas stutzeri were cultured at different levels of aeration (80 to 0% air s ...	1997	16535707
regulation of the synthesis and activity of ammonia monooxygenase in nitrosomonas europaea by altering ph to affect nh(inf3) availability.	the obligately ammonia-oxidizing bacterium nitrosomonas europaea was incubated in medium containing 50 mm ammonium. changes in the concentration of nitrite, the ph, and the nh(inf4)(sup+)- and nh(inf2)oh-dependent o(inf2) uptake activities of the cell suspension were monitored. the nh(inf4)(sup+)-dependent o(inf2) uptake activity doubled over the first 3 h of incubation and then slowly returned to its original level over the following 5 h. the extent of stimulation of nh(inf4)(sup+)-dependent o( ...	1997	16535741
transcript profiles of nitrosomonas europaea during growth and upon deprivation of ammonia and carbonate.	the transcriptome of nitrosomonas europaea was analyzed with whole-genome microarrays. growing cells were compared to cells deprived of (nh4)2so4 and na2co3. hybridization signals were detected for 76% of the genes represented on the array under either or both conditions. transcript levels for 68% of the genes were at least twofold higher in growing cells than in deprived cells, while only 0.42% of the genes were present at more than twofold higher levels in deprived cells. transcript levels for ...	2006	16553835
no reductase activity of the tetraheme cytochrome c554 of nitrosomonas europaea.	the tetraheme cytochrome c(554) (cyt c(554)) from nitrosomonas europaea is believed to function as an electron-transfer protein from hydroxylamine oxidoreductase (hao). we show here that cyt c(554) also has significant no reductase activity. the protein contains one high-spin and three low-spin c-type hemes. hao catalyzed reduction of the cyt c(554), ligand binding, intermolecular electron transfer, and kinetics of no reduction by cyt c(554) have been investigated. we detect the formation of a n ...	2006	16569009
expression, purification, crystallization and preliminary x-ray diffraction of a novel nitrosomonas europaea cytochrome, cytochrome p460.	cytochrome p460 from nitrosomonas europaea, a novel mono-heme protein containing an unusual cross-link between a conserved lysine and the porphyrin ring, has been recombinantly expressed and purified from escherichia coli. the protein crystallizes readily and diffraction to 1.7 angstroms has been obtained in-house. the crystals belong to the trigonal space group p3(1/2)21, with unit-cell parameters a = b = 53.3, c = 127.1 angstroms, and contain one monomer in the asymmetric unit.	2006	16582494
changes in the community structure and activity of betaproteobacterial ammonia-oxidizing sediment bacteria along a freshwater-marine gradient.	to determine whether the distribution of estuarine ammonia-oxidizing bacteria (aob) was influenced by salinity, the community structure of betaproteobacterial ammonia oxidizers (aob) was characterized along a salinity gradient in sediments of the ythan estuary, on the east coast of scotland, uk, by denaturant gradient gel electrophoresis (dgge), cloning and sequencing of 16s rrna gene fragments. ammonia-oxidizing bacteria communities at sampling sites with strongest marine influence were dominat ...	2006	16584480
o isotope shift in n nmr analysis of biological n-oxidations: h(2)o-no(2) exchange in the ammonia-oxidizing bacterium nitrosomonas.	the (18)o/(16)o shifts in (15)n nmr were determined for nitrite (0.13 ppm or 4.2 hz at 7.05 t) and nitrate (0.056 ppm or 1.7 hz at 7.05 t) at neutral ph. the technique, which allows clear differentiation between (16)o and (18)o derivatives of (15)n, was used to assess the source of oxygens in nitrite produced by oxidation of ammonia in nitrosomonas. the two oxygens of nitrite produced by cell-catalyzed oxidation of ammonia or hydroxylamine had the (16)o/(18)o isotope composition of water. nitros ...	1982	16593233
development and calibration of a nitrification pde model based on experimental data issued from biofilter treating drinking water.	to remove ammonia for production of drinking water, nitrification can be performed in a bio-filter. at least 1 month is necessary to capture from the groundwater and then grow a sufficient amount of nitrifying bacteria to reach the desired removal efficiency. improving start-up of bio-filters at low substrate concentration is therefore a major challenge. in this connection, it is important to develop appropriate models for designing, monitoring or analysing biofilm systems during start-up or fol ...	2006	16598794
characterization and quantification of ammonia-oxidizing bacteria in eutrophic coastal marine sediments using polyphasic molecular approaches and immunofluorescence staining.	tokyo bay, a eutrophic bay in japan, receives nutrients from wastewater plants and other urban diffuse sources via river input. a transect was conducted along a line from the arakawa river into tokyo bay to investigate the ecological relationship between the river outflow and the distribution, abundance and population structure of ammonia-oxidizing bacteria (aob). five surficial marine sediments were collected and analysed with polyphasic approaches. heterogeneity and genetic diversity of beta-a ...	2006	16623737
sequencing batch membrane biofilm reactor for simultaneous nitrogen and phosphorus removal: novel application of membrane-aerated biofilm.	a sequencing batch membrane biofilm reactor (sbmbfr) was developed for simultaneous carbon, nitrogen, and phosphorus removal from wastewater. this reactor was composed of two functional parts: (1) a gas-permeable membrane on which a nitrifying biofilm formed and (2) a bulk solution in which bacteria, mainly denitrifying polyphosphate-accumulating organisms (dnpaos), were suspended. the reactor was operated sequentially under anaerobic condition and then under membrane aeration condition in one c ...	2006	16673420
the combined toxic effects of nonpolar narcotic chemicals to pseudokirchneriella subcapitata.	this paper presents the toxicity data of 10 nonpolar narcotic chemicals on pseudokirchneriella subcapitata (green algae) assessed by a new algal toxicity testing technique conducted under air-tight environment. based on do production, median effective concentration (ec50) varies from 1.73 mg/l (1-octanol) to 8,040 mg/l (2-propanol). the endpoint of algal growth rate reveals similar sensitivity as that from do production. compared to literature data, pseudokirchneriella subcapitata and nitrosomon ...	2006	16687162
low-temperature epr and mössbauer spectroscopy of two cytochromes with his-met axial coordination exhibiting hals signals.	c-type cytochromes with histidine-methionine (his-met) iron coordination play important roles in electron-transfer reactions and in enzymes. low-temperature electron paramagnetic resonance (epr) spectra of low-spin ferric cytochromes c can be divided into two groups, depending on the spread of g values: the normal rhombic ones with small g anisotropy and g(max) below 3.2, and those featuring large g anisotropy with g(max) between 3.3 and 3.8, also denoted as highly axial low spin (hals) species. ...	2006	16688708
biosensor-based control of nitrification inhibitor in municipal wastewater treatment plants.	the effect of potassium cyanide (kcn) on nitrification processes in municipal wastewater treatment plants was studied by batch nitrification tests, which indicated that nitrification processes tend to be inhibited at a lower kcn concentration than the present discharge standard to sewerage. the experiment of the biosensor using nitrifying bacteria was also conducted for continuous monitoring of nitrification inhibitor in influent wastewater, and demonstrated that the biosensor can detect kcn at ...	2006	16722087
stoichiometric and kinetic characterisation of nitrosomonas sp. in mixed culture by decoupling the growth and energy generation processes.	a novel method that relies on the decoupling of the energy production and biosynthesis processes was used to characterise the maintenance, cell lysis and growth processes of nitrosomonas sp. a nitrosomonas culture was enriched in a sequencing batch reactor (sbr) with ammonium as the sole energy source. fluorescent in situ hybridization (fish) showed that nitrosomonas bound to the neu probe constituted 82% of the bacterial population, while no other known ammonium or nitrite oxidizing bacteria we ...	2006	16723160
solution structure of acyl carrier protein from nitrosomonas europaea.		2006	16741959
nitrification in a biofilm at low ph values: role of in situ microenvironments and acid tolerance.	the sensitivity of nitrifying bacteria to acidic conditions is a well-known phenomenon and generally attributed to the lack and/or toxicity of substrates (nh3 and hno2) with decreasing phs. in contrast, we observed strong nitrification at a ph around 4 in biofilms grown on chalk particles and investigated the following hypotheses: the presence of less acidic microenvironments and/or the existence of acid-tolerant nitrifiers. microelectrode measurements (in situ and under various experimental con ...	2006	16751543
transcriptome of a nitrosomonas europaea mutant with a disrupted nitrite reductase gene (nirk).	global gene expression was compared between the nitrosomonas europaea wild type and a nitrite reductase-deficient mutant using a genomic microarray. forty-one genes were differentially regulated between the wild type and the nirk mutant, including the nirk operon, genes for cytochrome c oxidase, and seven iron uptake genes. relationships of differentially regulated genes to the nirk mutant phenotype are discussed.	2006	16751567
real-time quantitative lamp (loop-mediated isothermal amplification of dna) as a simple method for monitoring ammonia-oxidizing bacteria.	loop-mediated isothermal amplification (lamp) of dna is a novel technique for the amplification of dna under isothermal conditions. for the first time, we applied this method to develop a simple and quantitative monitoring method for environmental microorganisms targeting amoa gene in ammonia-oxidizing bacteria. quantitative analysis was performed first by measuring fluorescence derived from an intercalation dye using a real-time thermal cycler, and then by measuring the turbidity of the reactio ...	2006	16790287
iron nutrition and physiological responses to iron stress in nitrosomonas europaea.	nitrosomonas europaea, as an ammonia-oxidizing bacterium, has a high fe requirement and has 90 genes dedicated to fe acquisition. under fe-limiting conditions (0.2 microm fe), n. europaea was able to assimilate up to 70% of the available fe in the medium even though it is unable to produce siderophores. addition of exogenous siderophores to fe-limited medium increased growth (final cell mass). fe-limited cells had lower heme and cellular fe contents, reduced membrane layers, and lower nh3- and n ...	2006	16802173
[enhanced ammonia removal and microbial community structure analysis using bacterial quinone profile in itfb].	water quality during the start-up period was changed in order to enhance the later nitrifying ability of the internal-circulation three-phase bio-fluidized bed (itfb). the experimental results showed that high n/c ratio and low feeding concentration of cod were two key conditions for enhancing the ammonia removal. after the enhanced start-up, an efficient removal efficiency of both cod and ammonia was achieved with hrt 2h when treating sanitary wastewater, the average ammonia removal rate was 74 ...	2006	16881325
quantification of ammonia-oxidizing bacteria populations in full-scale sewage activated sludge systems and assessment of system variables affecting their performance.	this study carried out quantification of ammonia-oxidizing bacteria (aob) populations in 12 full-scale sewage activated sludge systems that were different in ammonia removals and treatment processes during three different seasons. experiment was divided into 3 parts: 1) analysis of aob communities by pcr-dgge-cloning-sequencing of 16s rrna genes; 2) development of four real-time pcr primer sets for quantification of the particular aob of interest; and 3) quantification of aob populations by usin ...	2006	16898141
microbial community development in a laboratory-scale nitrifying activated sludge system with input from a side-stream bioreactor treating digester supernatant.	three laboratory-scale activated sludge treatment trains were operated to investigate the effect on biodiversity in plug flow (pfr) main-stream sewage treatment from input of biomass from side-stream reactors treating anaerobic digester supernatant. one train had a completely mixed (cstr) side-stream reactor, one a pfr side-stream reactor, and the third train was a control that did not receive input from a side-stream reactor. restriction endonucleases were used to digest polymerase chain reacti ...	2006	16898154
transcriptional analysis of the multicopy hao gene coding for hydroxylamine oxidoreductase in nitrosomonas sp. strain eni-11.	the nitrifying bacterium nitrosomonas sp. strain eni-11 has three copies of the gene encoding hydroxylamine oxidoreductase (hao(1), hao(2), and hao(3)) on its genome. broad-host-range reporter plasmids containing transcriptional fusion genes between hao copies and lacz were constructed to analyze the expression of each hydroxylamine oxidoreductase gene (hao) copy individually and quantitatively. beta-galactosidase assays of eni-11 harboring reporter plasmids revealed that all hao copies were tra ...	2006	16926500
post-treatment of a slaughterhouse wastewater: stability of the microbial community of a sequencing batch reactor operated under oxygen limited conditions.	slaughterhouse wastewater is a complex effluent with an important content of organic nitrogen. after an anaerobic treatment where most of the organic matter is removed, the nitrogen, remains as ammonium and post-treatment of the effluent is necessary. sequencing batch reactor (sbr) technology has been developed to completely remove nitrogen in one single reactor combining aerobic and anoxic stages. under oxygen limited conditions only nitrite is produced with concomitant energy saving. the stabi ...	2006	16939105
strategies of aerobic ammonia-oxidizing bacteria for coping with nutrient and oxygen fluctuations.	in most natural environments as well as in engineered environments, such as wastewater treatment plants, ammonia-oxidizing bacteria (aob) experience fluctuating substrate concentrations. several physiological traits, such as low maintenance energy demand and decay rate, cell-to-cell communication, cell mobility, stable enzymes and rnas, could allow aob to maintain themselves under unfavourable circumstances. this review examines whether aob possess such traits and how these traits might offer ad ...	2006	16958903
effect of free ammonia and free nitrous acid concentration on the anabolic and catabolic processes of an enriched nitrosomonas culture.	the effects of free ammonia (fa; nh(3)) and free nitrous acid (fna; hno(2)) concentrations on the metabolisms of an enriched ammonia oxidizing bacteria (aob) culture were investigated using a method allowing the decoupling of growth and energy generation processes. a lab-scale sequencing batch reactor (sbr) was operated for the enrichment of an aob culture. fluorescent in-situ hybridization (fish) analysis showed that 82% of the bacterial population in the sbr bound to the neu probe specifically ...	2006	16960893
cometabolism of trihalomethanes by mixed culture nitrifiers.	three mixed-culture nitrifier sources degraded low concentrations (25-450 microg/l) of four trihalomethanes (thms) (trichloromethane (tcm) or chloroform, bromodichloromethane (bdcm), dibromochloromethane (dbcm), tribromomethane (tbm) or bromoform) commonly found in treated drinking water. individual thm rate constants (k1thm) increased with increasing thm bromine-substitution with tbm>dbcm>bdcm>tcm and were comparable to previous studies with the pure culture nitrifier, nitrosomonas europaea. a ...	2006	16970971
diversity of ammonia-oxidizing archaea and bacteria in the sediments of a hypernutrified subtropical estuary: bahía del tóbari, mexico.	nitrification within estuarine sediments plays an important role in the nitrogen cycle, both at the global scale and in individual estuaries. although bacteria were once thought to be solely responsible for catalyzing the first and rate-limiting step of this process, several recent studies have suggested that mesophilic crenarchaeota are capable of performing ammonia oxidation. here we examine the diversity (richness and community composition) of ammonia-oxidizing archaea (aoa) and bacteria (aob ...	2006	17012598
molecular analysis of ammonia-oxidizing bacteria community in intermittent aeration sequencing batch reactors used for animal wastewater treatment.	bacterial communities and betaproteobacterial ammonia-oxidizing bacteria (aob) communities were evaluated seasonally in an intermittent-aeration sequencing batch process (sbr, plant a) and in 12 other livestock wastewater treatment plants (wwtp): eight sbrs and four conventional activated-sludge systems. microbial communities were analysed by reverse transcription polymerase chain reaction followed by denaturing-gradient gel electrophoresis (dgge) and the construction of clone libraries for 16s ...	2006	17014497
vertical distribution of nitrifying populations in bacterial biofilms from a full-scale nitrifying trickling filter.	cryosectioned biofilm from three depths (0.5, 3.0 and 6.0 m) in a full-scale nitrifying trickling filter (ntf) were studied using fluorescence in situ hybridization (fish). a large number of sections were used to determine how the biofilm thickness, structure and community composition varied with depth along the ammonium concentration gradient in the ntf, and how the ammonia-oxidizing bacteria (aob) and nitrite-oxidizing bacteria (nob) were distributed vertically within the biofilm. both the bio ...	2006	17014502
abundance and population structure of ammonia-oxidizing bacteria that inhabit canal sediments receiving effluents from municipal wastewater treatment plants.	a polyphasic, culture-independent study was conducted to investigate the abundance and population structure of ammonia-oxidizing bacteria (aob) in canal sediments receiving wastewater discharge. the abundance of aob ranged from 0.2 to 1.9% and 1.6 to 5.7% of the total bacterial fraction by real-time pcr and immunofluorescence staining, respectively. clone analysis and restriction endonuclease analysis revealed that the aob communities influenced by the wastewater discharge were dominated by nitr ...	2006	17021242
protonation and inhibition of nitrosomonas europaea cytochrome c peroxidase observed with protein film voltammetry.	the impact of protonation and inhibitor binding of the diheme cytochrome c peroxidase (ccp) from nitrosomonas europaea has been examined by the technique of catalytic protein film voltammetry (pfv). previous efforts have shown that the low-potential heme active site (l) binds substrate and yields electrocatalysis at an pyrolytic graphite edge electrode, with properties evocative of a high-potential intermediate, with e(m)>540mv (vs. normal hydrogen electrode) [a.l. bradley, s.e. chobot, d.m. arc ...	2007	17064778
heme crevice disorder after sixth ligand displacement in the cytochrome c-551 family.	1h nmr and visible absorption spectroscopy were used to monitor sixth ligand methionine displacement reactions in four members of the ferricytochrome c-551 family from pseudomonas aeruginosa, pseudomonas stutzeri, pseudomonas stutzeri substrain zobell, and nitrosomonas europae. potassium cyanide displaces the methionine ligand with very modest changes in the visible spectra, but profound changes in the nmr spectra. the initial product formed kinetically, designated complex i, changes with time a ...	2007	17078921
quantitative structure-activity relationships for toxicity of nonpolar narcotic chemicals to pseudokirchneriella subcapitata.	this study presents data for 27 nonpolar narcotic compounds regarding toxicity to pseudokirchneriella subcapitata as evaluated using a closed-system algal toxicity test with an exposure time of 48 h. two test endpoints, dissolved oxygen production and algal growth rate, were used to assess the toxicity of nonpolar narcotic chemicals on algae. hydrophobicity (1-octanol-water partition coefficient [k(ow)]) provided satisfactory descriptions for the toxicity of nonpolar narcotic compounds, and quan ...	2006	17089715
the expanded bed biofilter: combined nitrification, solids destruction, and removal of bacteria.	developed for tertiary nitrification, this biofilter also removed carbonaceous bod (cbod) and (ss). because the biofilter is expanded, it cannot clog, and therefore does not require backflushing; yet, it removed a significant proportion of the influent ss. this unanticipated capability was due to the activities of heterotrophic bacteria, protozoa, and metazoa (nematode and oligochaete worms). the expanded bed is an intensified process, which is based on natural immobilization of microbes to smal ...	2006	17163011
study on performance of granular anammox process and characterization of the microbial community in sludge.	anaerobic ammonium oxidation (anammox) is a novel biological nitrogen removal process, which is regarded as the most economical process at present. in this paper, two lab-scale uasb reactors, one of which was inoculated with the mixture of anaerobic sludge and aerobic sludge, the other with river sediments, were started up, using the inorganic synthetic water containing ammonium and nitrite as influent. after 421 days' and 356 days operation respectively, the ammonium removal efficiencies in two ...	2006	17163029
nitrogen removal rates at a technical-scale pilot plant with the one-stage partial nitritation/anammox process.	traditional nitrification/denitrification is not suitable for nitrogen removal when wastewater contains high concentrations of ammonium nitrogen and low concentrations of biodegradable carbon. recently, a deammonification process was developed and proposed as a new technology for treatment of such streams. this process relies on a stable interaction between aerobic bacteria nitrosomonas, that accomplish partial nitritation and anaerobic bacteria planctomycetales, which conduct the anammox reacti ...	2006	17163030
leachates from municipal solid waste disposal sites harbor similar, novel nitrogen-cycling bacterial communities.	high emissions of nitrous oxide (n(2)o) have recently been documented at municipal solid waste (msw) landfills. however, the biodiversity of the bacterial populations involved remains unexplored. in this study, we investigated communities of ammonia-oxidizing bacteria (aob) and denitrifying bacteria associated with the leachates from three msw disposal sites by examining the diversity of the ammonia monooxygenase structural gene amoa and the nitrous oxide reductase gene nosz, respectively. cloni ...	2007	17169002
characterization and performance of constructed nitrifying biofilms during nitrogen bioremediation of a wastewater effluent.	constructed ammonium oxidizing biofilms (caob) and constructed nitrite oxidizing biofilms (cnob) were characterized during the bioremediation of a wastewater effluent. the maximum ammonium removal rate and removal efficiency in caob was 322 mg n-nh4+ m(-3) d(-1) and 96%, respectively, while in cnob a maximum removal rate of 255 mg n-nh4+ m(-3) d(-1) and a removal efficiency of 76% was achieved. both constructed biofilms on low-density polyester dacron support achieved removal efficiencies higher ...	2007	17186207
influences of infaunal burrows on the community structure and activity of ammonia-oxidizing bacteria in intertidal sediments.	influences of infaunal burrows constructed by the polychaete (tylorrhynchus heterochaetus) on o(2) concentrations and community structures and abundances of ammonia-oxidizing bacteria (aob) and nitrite-oxidizing bacteria (nob) in intertidal sediments were analyzed by the combined use of a 16s rrna gene-based molecular approach and microelectrodes. the microelectrode measurements performed in an experimental system developed in an aquarium showed direct evidence of o(2) transport down to a depth ...	2007	17189445
nitrification inhibitors from the root tissues of brachiaria humidicola, a tropical grass.	nitrification inhibitory activity was found in root tissue extracts of brachiaria humidicola, a tropical pasture grass. two active inhibitory compounds were isolated by activity-guided fractionation, using recombinant nitrosomonas europaea containing luxab genes derived from the bioluminescent marine gram-negative bacterium vibrio harveyi. the compounds were identified as methyl-p-coumarate and methyl ferulate, respectively. their nitrification inhibitory properties were confirmed in chemically ...	2007	17243702
diversity study of nitrifying bacteria in full-scale municipal wastewater treatment plants.	we hypothesize that activated-sludge processes having stable and complete nitrification have significant and similar diversity and functional redundancy among its ammonia- and nitrite-oxidizing bacteria, despite differences in temperature, solids retention time (srt), and other operating conditions. to evaluate this hypothesis, we examined the diversity of nitrifying bacterial communities in all seven water-reclamation plants (wrps) operated by metropolitan water reclamation district of greater ...	2007	17254627
direct electrochemistry of tetraheme cytochrome c(554) from nitrosomonas europaea: redox cooperativity and gating.		2007	17263529
investigation of total bacterial and ammonia-oxidizing bacterial community composition in a full-scale aerated submerged biofilm reactor for drinking water pretreatment in china.	the community composition of total bacteria and ammonia-oxidizing bacteria in a full-scale aerated submerged biofilm reactor for drinking water pretreatment was characterized by analysis of 16s rrna gene and the functional gene amoa, respectively. sampling was performed in february and in july. 16s rrna gene clone libraries revealed 13 bacterial divisions. at both sampling dates, the majority of clone sequences were related to the alpha- and betaproteobacteria. a minor proportion belonged to the ...	2007	17263855
cytochromes p460 and c'-beta; a new family of high-spin cytochromes c.	cytochromes-p460 of nitrosomonas europaea and methylococcus capsulatus (bath), and the cytochrome c' of m. capsulatus, believed to be involved in binding or transformation of n-oxides, are shown to represent an evolutionarily related new family of monoheme, approximately 17kda, cytochromes c found in the genomes of diverse proteobacteria. all members of this family have a predicted secondary structure predominantly of beta-sheets in contrast to the predominantly alpha-helical cytochromes c' foun ...	2007	17292891
molecular diversity of nitrite reductase genes (nirk) in nitrifying bacteria.	sequences of copper-containing nitrite reductase (nirk) genes obtained from completed nitrifier genome sequences were used to design polymerase chain reaction (pcr) primers to amplify partial nirk sequences from one nitrosomonas and four nitrosospira isolates. deduced nirk protein sequences were highly similar to other copper-containing nitrite reductases including conserved motifs. phylogenetic comparisons of nirk protein sequences placed orthologues from nitrosomonas, nitrosospira and nitrobac ...	2007	17298375