| inhibition of nitrifying bacteria by grass and forb root extracts. | | 1969 | 5798521 |
| phosphoenolpyruvate carboxylase of thiobacillus thiooxidans. kinetic and metabolic control properties. | | 1972 | 4552310 |
| growth of mixed cultures of autotrophic and heterotrophic organisms. | | 1972 | 4622985 |
| specific inhibitors of ammonia oxidation in nitrosomonas. | the following compounds or treatments have been shown to inhibit the oxidation of ammonia, but not the oxidation of hydroxylamine in cells of nitrosomonas: (i) metal-binding agents such as allylthiourea or potassium cyanide; (ii) compounds such as skf 525 which interact with cytochrome p-450 of mammalian microsomes; (iii) carbon monoxide; (iv) inhibitors of catalase, peroxidase, and amine oxidases such as thiosemicarbazide, ethylxanthate, and iproniazid, respectively; (v) uncouplers of oxidative ... | 1973 | 4725614 |
| nucleic acid composition of nitrosomonas europaea. | | 1965 | 5862235 |
| purification and properties of peroxidase from nitrosomonas europaea. | peroxidase from the obligate chemosynthetic bacterium nitrosomonas europaea was purified 1,500-fold, and its properties were examined. the enzyme had a molecular weight of 53,000 and exhibited characteristic absorption maxima at 410, 524, and 558 mmu. the optimal ph and temperature were 7.5 and 44 c, respectively. the peroxidase reaction had an energy of activation of 5,850 cal/mole and required a primary substrate (h(2)o(2)) concentration of 7 x 10(-6)m to proceed at half maximal velocity (k(m) ... | 1968 | 5663576 |
| deoxyribonucleic acid base composition and taxonomy of thiobacilli and some nitrifying bacteria. | | 1968 | 5677980 |
| the effect of dd nematocide on soil micro-organisms. | | 1968 | 5679913 |
| talc as a growth medium for nitrite forming bacteria (nitrosomonas). | | 1968 | 5755997 |
| studies of the hydroxylamine metabolism of nitrosomonas europaea. i. purification of hydroxylamine oxidase. | | 1968 | 5758552 |
| studies on the hydroxylamine metabolism of nitrosomonas europaea. ii. molecular properties of the electron-transport particle, hydroxylamine oxidase. | | 1968 | 5758553 |
| macromolecular subunits in the walls of marine nitrifying bacteria. | the outteromost laver of the cell wall of all marine ammonia-oxidizing bacteria so far isolated is made up of protein subunits arranged in a regular manner and linked together through metal-oxygen bonds. this sculptured, outer wall layver appears to be uniique to the terrestrial ammonia-oxidizing bacteria. | 1969 | 5762933 |
| lag phase of ammonia oxidation by resting cells of nitrosomonas eruopaea. | | 1969 | 5773042 |
| [quantitative determination of cytochromes from nitrosomonas europaea]. | | 1966 | 6004936 |
| uptake and utilization of amino acids by resting cells of nitrosomonas europaea. | incorporation of selected amino acids by resting cells was studied with regard to effects of concentration, rate and extent of incorporation, cellular distribution, effect of ammonium ion on uptake, and competitive effects. l-aspartic acid, l-alanine, l-serine, and glycine presented at trace levels were incorporated at rates ranging from 0.11 to 8.2 mumumoles per mg (dry weight) per minute, and maximal incorporation was 11 to 333 mumumoles per mg (dry weight). when glycine and aspartic acid were ... | 1967 | 6032509 |
| metabolism of inorganic nitrogen compounds in plants and micro-organisms. | | 1972 | 5085571 |
| persistence and effects of some chlorinated anilines on nitrification in soil. | | 1969 | 5796122 |
| fatty acids in the lipids of marine and terrestrial nitrifying bacteria. | fatty acids in the lipids of 19 marine and terrestrial nitrifying bacteria have been analyzed. ammonia-oxidizing bacteria have a very simple acid composition; palmitic and palmitoleic acid account for 96 to 100% of the total acids. the fatty acids of nitrite-oxidizing bacteria cover a wider range, from c(14) to c(19), but from two to four acids still account for more than 80% of the total acids. branched iso- and anteiso-acids are present in traces only in 2 of the 19 bacteria. the chemical and ... | 1969 | 5808068 |
| studies on the oxidation of ammonia to hydroxylamine by nitrosomonas. | | 1964 | 5840380 |
| the scope of the eater pollution problem. | | 1971 | 5161226 |
| characterization of hydroxylamine-cytochrome c reductase from the chemoautotrophs nitrosomonas europaea and nitrosocystis oceanus. | | 1965 | 5842070 |
| the antibacterial effect of dry tomato plants, onion peels, and guava leaves on soil microorganisms. | | 1971 | 5172508 |
| hydroxylamine oxidoreductase: a 20-heme, 200 000 molecular weight cytochrome c with unusual denaturation properties which forms a 63 000 molecular weight monomer after heme removal. | | 1981 | 6274384 |
| nitrification. | | 1966 | 5326519 |
| oxidation of ammonia by spheroplasts of nitrosomonas europaea. | the ammonia-oxidizing activity of nitrosomonas europaea spheroplasts was restored by addition of hydroxylamine or by preincubation with mg(2+). | 1969 | 5370285 |
| polyphosphate and orthophosphate content of nitrosomonas europaea as a function of growth. | after inoculation of a stationary-phase culture of nitrosomonas europaea into fresh growth solution, the cell-associated orthophosphate increased rapidly to 800 mumoles/g (wet weight), whereas the acid-insoluble long-chain polyphosphate content decreased rapidly to 22 mumoles/g. as growth proceeded, the orthophosphate content decreased rapidly to a level of 15 mumoles/g and the long-chain polyphosphate content gradually increased to 60 to 90 mumoles/g. when the ph of a culture of nitrosomonas de ... | 1970 | 5423370 |
| cell-free ammonia oxidation by nitrosomonas europaea extracts: effects of polyamines, mg2+ and albumin. | | 1970 | 5423832 |
| use of the nitrifying chemoautotroph nitrosomonas for assay of ammonia. | | 1970 | 5439492 |
| effects of some phenylamide herbicides and their degradation products on soil nitrification. | | 1970 | 5471337 |
| function of dislocations in cell walls and membranes. | | 1970 | 5477009 |
| a possible role for the species peroxonitrite in nitrification. | | 1970 | 5496491 |
| effect of chloride on oxidation of hydroxylamine by nitrosomonas europaea cells. | | 1968 | 5636823 |
| [products of short-term chemosynthesis in nitrosomonas europaea]. | | 1965 | 5887011 |
| effect of mixed culture on nitrosomonas europaea simulated by uptake and utilization of pyruvate. | clark, connie (university of minnesota, minneapolis), and e. l. schmidt. effect of mixed culture on nitrosomonas europaea simulated by uptake and utilization of pyruvate. j. bacteriol. 91:367-373. 1966.-contamination of a 5-liter culture of nitrosomonas europaea resulted in enhanced nitrite formation as compared with pure cultures. the dominant contaminant, a yellow-pigmented, heterotrophic bacterium, was isolated and studied both in pure culture and in deliberate mixture with n. europaea. growt ... | 1966 | 5903103 |
| phospholipids of bacteria with extensive intracytoplasmic membranes. | examination of the lipids of three species of nonphotosynthetic bacteria with extensive internal membranes revealed phosphatidyl choline (lecithin) in two species. in one of these there was an unusual accumulation of phosphatidyl n-dimethylethanolamine. (the relation between lecithin and membrane elaboration in microorganisms is discussed.) | 1966 | 5909586 |
| incorporation of atmospheric oxygen in nitriteformed during ammonia oxidation by nitrosomonas europaea. | | 1966 | 5942439 |
| growth of some chemoautotrophic bacteria at different oxygen tensions. | | 1966 | 5955989 |
| heme p460 of hydroxylamine oxidoreductase of nitrosomonas. reaction with co and h2o2. | hydroxylamine oxidoreductase (hao) of nitrosomonas catalyzes the dehydrogenation of nh2oh and subsequent addition of oxygen to form nitrite. hao contains c hemes and the co-binding heme p460 in a 7:1 ratio; dehydrogenation of nh2oh involves passage of electrons to p460 and then c hemes. we now report that electrons rapidly pass from c hemes of hao to the p460 center and then to h2o2. this conclusion is supported by (a) inhibition of c heme oxidation with co and (b) loss of h2o2-oxidizability of ... | 1983 | 6861765 |
| studies on the incorporation of co2 by cells and cell-free extracts of nitrosomonas europaea. | | 1966 | 5968895 |
| [morphological forms of nitrosomonas europeaea and their physiological peculiarities]. | | 1966 | 6004698 |
| interference by cells of nitrosomonas with the estimation of nitrite. | | 1967 | 6073519 |
| oxygen-nitrogen relationships in autotrophic nitrification. | oxygen utilization by the autotrophic nitrifiers nitrosomonas and nitrobacter was studied. experimental evidence is presented which reflects the effect of carbon dioxide fixation on overall oxygen utilization in autotrophic nitrification. measurement of dissolved oxygen and inorganic nitrogen changes indicates that oxygen-nitrogen ratios in inorganic nitrogen oxidation are equal to 3.22 parts (expressed in milligrams per liter) of oxygen per part of ammonia nitrogen oxidized to nitrite nitrogen ... | 1967 | 6077417 |
| some properties of glutamine synthetase from the nitrifying bacterium nitrosomonas europaea. | nitrosomonas europaea oxidizes ammonia to nitrite, thereby deriving energy for growth. glutamate dehydrogenase (nadp+) (ec 1.4.1.4) is the main route for the incorporation of ammonia into glutamic acid, because glutamate synthase (nadph)(ec 1.4.1.13) was not detected in cell-free extracts of n. europaea. some properties of a partially purified glutamine synthetase (ec 6.3.1.2) have been determined, namely the effects of ph and metal ions, substrate requirements, km and ki values, based on biosyn ... | 1981 | 6122437 |
| 3,3',5,5'-tetramethylbenzidine/h2o2 staining is not specific for heme proteins separated by gel electrophoresis. | staining of sodium dodecyl sulfate or lithium dodecyl sulfate gels with 3,3',5,5'-tetramethylbenzidine (tmbz)/h2o2 after electrophoresis has frequently been used as a specific method of detecting heme proteins. that tmbz is an electron donor for o2 reduction by the nonheme-soluble cytochrome oxidase/nitrite reductase from nitrosomonas europaea is now shown; this protein is detected by the tmbz/h2o2 method. a method for the determination of tmbz oxidase activity is given; hence, the detection of ... | 1984 | 6207749 |
| preparation of membrane vesicles in lithium chloride from cells of nitrosomonas europaea. | | 1980 | 6261609 |
| cell-free ammonia-oxidizing system of nitrosomonas europaea: general conditions and properties. | conditions essential for the preparation of active ammonia-oxidizing extracts of nitrosomonas europaea were studied. the extracts were unstable during storage and required specific assay conditions for ammonia oxidation. bovine serum albumin, spermine, or mgcl2 was required for ammonia oxidation and the concentration of phosphate determined the relative effectiveness of each activator, i.e., albumin being most effective in 0.1 m phosphate and spermine or mgcl2 at lower phosphate concentrations. ... | 1981 | 6271363 |
| a partial resolution and reconstitution of the ammonia-oxidizing system of nitrosomonas europaea: role of cytochrome c554. | the cell-free ammonia-oxidizing system of nitrosomonas europaea was resolved into three major fractions: a membrane fraction containing cytochrome a1 and c-type cytochromes, a fraction with hydroxylamine-cytochrome c reductase and a cytochrome c fraction. the ammonia-oxidizing activity was reconstituted by the combination of these three fractions. the activity was more consistently reconstituted by adding nitrosomonas cytochrome c554 to the membrane fraction. the hydroxylamine-cytochrome c reduc ... | 1981 | 6271364 |
| respiration-dependent proton translocation in nitrosomonas europaea and its apparent absence in nitrobacter agilis during inorganic oxidations. | oxygen pulse experiments were carried out with the nitrifying bacteria nitrosomonas europaea and nitrobacter agilis and with spheroplasts and everted vesicles prepared from nitrobacter agilis. in addition to thiocyanate, the salting-in anions perchlorate and trichloroacetate proved to be permeant and effective in allowing respiration-dependent proton translocation with nitrosomonas europaea. valinomycin-k+, however, was generally ineffective in this respect with nitrosomonas europaea. the observ ... | 1982 | 6277846 |
| resolution of multiple heme centers of hydroxylamine oxidoreductase from nitrosomonas. 1. electron paramagnetic resonance spectroscopy. | | 1982 | 6289867 |
| a p-450-like cytochrome and a soluble terminal oxidase identified as cytochrome o from nitrosomonas europaea. | | 1965 | 5866846 |
| cytochrome c554 as a possible electron donor in the hydroxylation of ammonia and carbon monoxide in nitrosomonas europaea. | mechanism of ammonia oxidation was studied in the reconstituted system of nitrosomonas membrane fraction plus the nitrosomonas cytochrome c554. the cytochrome c554 was reduced by hydroxylamine, hydrazine, and ammonia and the reduced cytochrome was oxidized upon the addition of ammonia or carbon monoxide. the oxidation of carbon monoxide in the presence of hydroxylamine or hydrazine was studied as a possible assay method for ammonia hydroxylase where hydroxylamine or hydrazine was supplying the r ... | 1982 | 6293683 |
| characterization of the c-type cytochromes of nitrosomonas europaea with the aid of fluorescent gels. | when a total soluble extract of nitrosomonas europaea was denatured with dodecyl sulphate, subjected to dodecyl sulphate/polyacrylamide-gel electrophoresis and illuminated with near-u.v. light, eight bands of protein fluorescence were observed. all but one of these bands were red in colour, a property characteristic of c-type cytochromes. standard techniques were used to purify soluble c-type cytochromes from this organism, and it was then possible to assign all but two very minor bands to speci ... | 1982 | 6299271 |
| co-binding c-type cytochromes and a high-potential cytochrome c in nitrosomonas europaea. | the purification of two soluble co-binding cytochromes c from nitrosomonas europaea is described. cytochrome cco-550 ran on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis with an apparent mr of 32 000, whereas for cytochrome cco-552 the apparent mr was 16 000. redox potentials (em, 7) were determined as +140 and -50mv respectively. cytochrome cco-550 was co-purified with a cytochrome c-553, for which an unusually high redox potential of +450mv was measured. these latter components we ... | 1983 | 6307283 |
| diheme cytochrome c-554 from nitrosomonas. soret resonance raman indication of an unusual ferric 5-coordinate structure. | the diheme cytochrome c-554 which participates in ammonia oxidation in the chemoautotroph , nitrosomonas europaea has been studied by soret excitation resonance raman spectroscopy. the raman spectrum of reduced cytochrome c-554 at neutral ph is similar classical 6-coordinate low-spin ferrous mammalian cytochrome c. in contrast, the spectrum of ferric cytochrome c-554 suggests a 5-coordinate state which is unusual for c hemes. the oxidized spectrum closely resemble that of horseradish peroxidase ... | 1984 | 6327385 |
| mössbauer, epr, and optical studies of the p-460 center of hydroxylamine oxidoreductase from nitrosomonas. a ferrous heme with an unusually large quadrupole splitting. | hydroxylamine oxidoreductase from nitrosomonas europeae catalyzes the oxidative conversion of nh2oh to no-2. the enzyme, mr = 220,000, has an (alpha beta)3 subunit structure with each alpha beta subunit containing 7-8 c-type hemes and one unusual prosthetic group, termed p-460. the p-460 is also found in a mr approximately equal to 17,000 protein (p-460 fragment). mössbauer spectra of the reduced p-460 groups, in hydroxylamine oxidoreductase and the fragment, exhibit nearly identical quadrupole ... | 1984 | 6327697 |
| kinetics of reduction by substrate or dithionite and heme-heme electron transfer in the multiheme hydroxylamine oxidoreductase. | hydroxylamine oxidoreductase of nitrosomonas catalyzes the dehydrogenation of nh2oh. it contains hemes c553, c559 and p460 in the ratio 5:2:1. at equilibrium four or five c hemes are reduced by nh2oh or nh2nh2, respectively. heme p460 is the site of electron entry into the enzyme; electrons exit via p460 to o2 or h2o2 with rate constants of 30s-1. we report that hydroxylamine oxidoreductase has two categories of electron-accepting sites: (a) heme p460, an h2o2-sensitive site, which is reactive w ... | 1984 | 6745259 |
| [comparative characteristics of the enzymatic systems of methane-utilizing bacteria that oxidize nh2oh and ch3oh]. | methane hydroxylase (mh) from the obligate methane assimilating culture of methylococcus thermophilus catalyses oxygenation of both ch4+ and nh4+; therefore, we studied the specificity of enzyme systems catalysing the subsequent oxidation of compounds produced upon the oxygenation of these substrates (ch3oh and nh2oh). ch3oh and nh2oh were shown to be oxidized by different enzymes, viz. methanol dehydrogenase (md) and hydroxylamine oxidase (ho), respectively. similar to mh, md is characterized b ... | 1980 | 6771495 |
| effects of polychlorinated biphenyls and environmental biotransformation products on aquatic nitrification. | the effects of polychlorinated biphenyls (pcbs) on nitrification were examined for pure cultures and natural reservoir samples. pcbs at concentrations greater than 10 microgram liter-1 inhibited nitrification, principally ammonium oxidation, in one of two natural reservoir environments. however, this inhibition could not be reproduced in pure high-cell-density cultures or in previously contaminated reservoir waters. a pcb environmental biotransformation product, p-chlorophenylglyoxylic acid, and ... | 1982 | 6805434 |
| proton electrochemical gradients in washed cells of nitrosomonas europaea and nitrobacter agilis. | the components of the proton motive force (deltap), namely, membrane potential (deltapsi) and transmembrane ph gradient (deltaph), were determined in the nitrifying bacteria nitrosomonas europaea and nitrobacter agilis. in these bacteria both deltapsi and deltaph were dependent on external ph. thus at ph 8.0, nitrosomonas europaea and nitrobacter agilis had deltapsi values of 173 mv and 125 mv (inside negative), respectively, as determined by the distribution of the lipophilic cation [(3)h]tetra ... | 1983 | 6833187 |
| methane oxidation by nitrosomonas europaea. | methane inhibited nh4+ utilization by nitrosomonas europaea with a ki of 2mm. o2 consumption was not inhibited. in the absence of nh4+, or with hydrazine as reductant, methane caused nearly a doubling in the rate of o2 uptake. the stimulation was abolished by allylthiourea, a sensitive inhibitor of the oxidation of nh4+. analysis revealed that methanol was being formed in these experiments, with yields approaching 1 mol of methanol per mol of o2 consumed under certain conditions. when cells were ... | 1983 | 6870854 |
| reaction of oxygen with hydroxylamine oxidoreductase of nitrosomonas: fast kinetics. | | 1982 | 7117545 |
| resolution of multiple heme centers of hydroxylamine oxidoreductase from nitrosomonas. 2. mössbauer spectroscopy. | hydroxylamine oxidoreductase (hao) isolated from nitrosomas europaea is a complex protein of mr 220000 with an (alpha beta)3 subunit structure. each alpha beta subunit contains seven c-type hemes and approximately one unusual prosthetic group termed p-460. we have studied this enzyme in the oxidized and reduced states by using mössbauer spectroscopy. in the fully reduced enzyme, approximately seven hemes per alpha beta subunit contributed to one spectrum characteristic of low-spin ferrous heme. ... | 1982 | 7126527 |
| incorporation of organic compounds into cell protein by lithotrophic, ammonia-oxidizing bacteria. | incorporation of organic compounds into cell protein by the obligate chemolithotrophs nitrosomonas spec., nitrosococcus oceanus, nitrosococcus mobilis, nitrosovibrio tenuis, nitrosolobus spec., and nitrosospira spec. was studied. in the presence of ammonia as energy source organic substrates were supplied. distribution of 14c into cell amino acids arising from 14c-labelled glucose, na-pyruvate, and na-acetate was investigated. while carbon from glucose was distributed unrestricted, carbon from p ... | 1982 | 7149699 |
| serological studies on lithotrophic, ammonia oxidizing bacteria. | rabbit antisera were prepared against living cells of six different ammonia oxidizing nitrifying bacteria. they were examined as to cross-reactivity in the agglutination test (microtiter-system) with 24 nitrifier strains, including members of all known genera. usually distinct cross-reactions were obtained only within the genera, but some exceptions were noticed. there was stated a clear cross-reaction between the two anti-nitrosospira-antisera and the four tested nitrosolobus strains. in some c ... | 1980 | 7212926 |
| oxidation of ammonia by nitrosomonas europaea. definite 18o-tracer evidence that hydroxylamine formation involves a monooxygenase. | nh2oh, the first intermediate in the oxidation of nh4+ to nitrite by the nitrifying bacterium, nitrosomonas europaea, was recovered as the oxime of cyclohexanone. 15n, 18o-tracer experiments using highly enriched 15nh4cl and 18o2 yielded oxime that was correspondingly highly enriched (greater than or equal to 92 atom %) in these isotopes. these results show that the source of nh2oh is largely or entirely nh4+, as opposed to hydrazine, which was added to inhibit the further oxidation of nh2oh to ... | 1981 | 7287737 |
| interaction with membranes of cytochrome c554 from nitrosomonas europaea. | two c-cytochromes extrinsically bound to the membranes of nitrosomonas europaea have been identified. one is the tetraheme cytochrome c554, a protein previously described as soluble and periplasmic. depending on the concentration of fe and cu in the growth medium, from 50 to 100% of the total cellular cytochrome c554 is membrane-associated. the cytochromes c554 found in the soluble or membrane fractions are identical in the spectroscopic, chromatographic, or primary structural properties examine ... | 1995 | 7503559 |
| the dynamic progression of evolved character states for aromatic amino acid biosynthesis in gram-negative bacteria. | a systematic analysis of the evolution of aromatic amino acid biosynthesis in the proteobacteria, previously focussed mainly upon the gamma subdivision, has now been extended to the beta subdivision. five lineages were studied, represented by neisseria gonorrhoeae, nitrosomonas europaea, alcaligenes faecalis, rrna group-iii pseudomonads/rubrivivax gelatinosus, and rrna group-ii pseudomonads/rhodocyclus tenuis. within the phenylalanine pathway, the bifunctional p-protein (chorismate mutase/prephe ... | 1994 | 7533594 |
| detection of ammonium-oxidizing bacteria of the beta-subclass of the class proteobacteria in aquatic samples with the pcr. | the pcr was used as the basis for the development of a sensitive and specific assay for the detection of ammonium-oxidizing bacteria belonging to the beta-subclass of the class proteobacteria. pcr primers were selected on the basis of nucleic acid sequence data available for seven species of nitrifiers in this subclass. the specificity of the ammonium oxidizer primers was evaluated by testing known strains of nitrifiers, several serotyped environmental nitrifier isolates, and other members of th ... | 1995 | 7538277 |
| nih shift in the hydroxylation of aromatic compounds by the ammonia-oxidizing bacterium nitrosomonas europaea. evidence against an arene oxide intermediate. | the migration of deuterium and hydrogen was observed in the aromatic hydroxylation of specifically deuterated, monosubstituted benzenes catalyzed by ammonia monooxygenase of nitrosomonas europaea. the phenolic products of the hydroxylation of aromatics containing ortho-/para-directing substituents (f, cl, br, i, oh, nh2, ch3, ch2ch3, and och3) were primarily para-phenols. in contrast, with aromatics containing meta-directing substituents (no2 and cn), the phenolic products were a more even mixtu ... | 1995 | 7547906 |
| sequence of an ammonia monooxygenase subunit a-encoding gene from nitrosospira sp. npav. | one of three gene copies encoding ammonia monooxygenase subunit a (amoa) and flanking sequences was isolated from genomic dna of the chemolithotrophic soil bacterium nitrosospira sp. npav using oligodeoxyribonucleotide primers and the polymerase chain reaction (pcr). the gene (amoa) encodes a 274-amino-acid polypeptide which has similarity to the ammonia monooxygenase acetylene-binding protein from nitrosomonas europaea. | 1995 | 7557469 |
| a di-heme cytochrome c peroxidase from nitrosomonas europaea catalytically active in both the oxidized and half-reduced states. | a di-c-heme containing cytochrome (cytochrome c553 peroxidase) has been isolated from the chemoautotrophic bacterium nitrosomonas europaea. sequence analysis of the n terminus and the two heme-containing peptides generated by digestion of the enzyme with trypsin show 40% homology overall to sequences reported for the di-heme peroxidase from pseudomonas aeruginosa (rönnberg, m., kalkkinen, n., and ellfolk, n. (1989) febs lett. 250, 175-178). at room temperature and ph 7.0, one heme is low spin wi ... | 1994 | 8163487 |
| amplification of the amoa gene from diverse species of ammonium-oxidizing bacteria and from an indigenous bacterial population from seawater. | because the chemolithotrophic ammonium-oxidizing bacteria are an integral component of nitrogen biogeochemistry, a sensitive and accurate method to detect this ecologically important group of microorganisms is needed. the amoa gene of these organisms encodes the active site of ammonia monooxygenase, an enzyme unique to this group of nitrifying bacteria. we report here the use of the pcr technique to detect the amoa gene from pure cultures of chemolithotrophic ammonium-oxidizing bacteria, ammoniu ... | 1995 | 7618882 |
| reaction with cyanide of hydroxylamine oxidoreductase of nitrosomonas europaea. | hydroxylamine oxidoreductase (hao) catalyzes the reaction nh2oh+h2o-->hno2+4e- + 4h+, a step in the energy-generating oxidation of ammonia to nitrite by the bacterium nitrosomonas europaea. each subunit of hao contains 7 c-hemes and 1 heme p460. the latter, c-heme cross-linked from a methylene carbon to the ring of a protein tyrosine, forms part of the active site. the iron of heme p460 is probably linked by a bridging ligand to the iron of a c-heme. here, the reaction of cyanide with ferric hao ... | 1995 | 7619802 |
| suicide inactivation of hydroxylamine oxidoreductase of nitrosomonas europaea by organohydrazines. | in the presence of a suitable electron acceptor such as mammalian cytochrome c, hydroxylamine oxidoreductase (hao) from the chemolithotrophic bacterium nitrosomonas europaea catalyzes the oxidation of hydroxylamine or hydrazine to nitrite or dinitrogen, respectively. each subunit of hao contains 7 c-hemes and a chromophore of the active site called heme p460, a c-heme bridged from a methylene carbon to a ring carbon of a tyrosine of the peptide chain. reaction with either substrate results in re ... | 1995 | 7619827 |
| generation of polymerase chain reaction-specific probes for library screening using single degenerate primers. | degenerate oligonucleotide primers were made to peptide sequences from hydroxylamine oxidoreductase (hao) from nitrosomonas europaea. the primers were used singly in pcr reactions to amplify portions of the gene for hao from genomic dna. southern hybridizations using fragments amplified with each primer showed that they labeled the same genomic dna fragments. the pcr-amplified fragments were successfully used to screen a gene library for clones containing the hao gene. the method of isolating ge ... | 1995 | 7648471 |
| hybrid biosensor for clinical and fermentation process control. | | 1984 | 6596903 |
| hydroxylamine oxidoreductase from nitrosomonas europaea is a multimer of an octa-heme subunit. | a fully active form of hydroxylamine oxidoreductase from nitrosomonas has been purified with high recovery and shown by reverse-phase high performance liquid chromatography and n-terminal analysis to contain only a 63-kda subunit and to lack the 11-kda protein previously thought to be a second subunit. based on the previously published values of molecular weight in solution, hydroxylamine oxidoreductase probably has an alpha 2 or alpha 3 oligomeric structure. the enzyme was digested separately w ... | 1993 | 8325841 |
| resolution of the hemes of hydroxylamine oxidoreductase by redox potentiometry and optical spectroscopy. | optical spectroscopy combined with redox potentiometry has resolved the hemes of hydroxylamine oxidoreductase into 6 thermodynamically distinct classes. there are apparently 4 classes of heme c553, with em7-values of 295 mv, 10 mv, -190 mv and -390 mv, present in a stoichiometry of 1:1:2:1; two equivalents of heme c559, em7 o mv, and one of heme p-460, an unusual chromophore, with em7 -260 mv. | 1983 | 6628687 |
| na+ and k+ transport in nitrosomonas europaea and nitrobacter agilis. | potassium-depleted cells of nitrosomonas europaea and nitrobacter agilis were prepared by diethanolamine treatment and contained less than 5 mm intracellular k+. the addition of k+ to k+-depleted cells of n. europaea and n. agilis resulted in a depolarization of membrane potential (delta psi) by about 5 and 10 mv, respectively. this depolarization was, however, compensated by an equivalent increase in transmembrane ph gradient (delta ph), so that the total proton-motive force (delta p) remained ... | 1984 | 6733088 |
| anaerobic oxidation of ammonium is a biologically mediated process. | a newly discovered process by which ammonium is converted to dinitrogen gas under anaerobic conditions (the anammox process) has now been examined in detail. in order to confirm the biological nature of this process, anaerobic batch culture experiments were used. all of the ammonium provided in the medium was oxidized within 9 days. in control experiments with autoclaved or raw wastewater, without added sludge or with added sterilized (either autoclaved or gamma irradiated) sludge, no changes in ... | 1995 | 7747947 |
| the amino acid sequence of nitrosomonas europaea cytochrome c-552. | the complete amino acid sequence of cytochrome c-552 derived from the chemoautotrophic ammonia-oxidizing bacterium nitrosomonas europaea was determined. the cytochrome consisted of 81 amino acid residues, and its molecular weight was calculated to be 9098 including heme c. although the sequence of cytochrome c-552 was highly homologous to those of cytochromes c-551, which were known as the electron-donating components to dissimilatory nitrite reductase in pseudomonads, cytochrome c-552 differed ... | 1995 | 7767224 |
| the use of a hollow fiber membrane module in sample conditioning prior to electrophoresis. | a new method to continuously change the buffer conditions in samples prior to electrophoresis by counter-current dialysis has been developed using a hollow fiber membrane module (variperm m, bitop, witten). it is demonstrated that the collected fractions of a column eluate after hydrophobic interaction chromatography cannot be analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (sds-page) due to the high content of ammonium sulfate. in contrast, when the hollow fiber membrane m ... | 1994 | 7859717 |
| crystallization and preliminary x-ray analysis of cytochrome c-552 from nitrosomonas europaea. | cytochrome c-552 from nitrosomonas europaea was crystallized by the sandwiched drop, vapor diffusion method, with anmmonium sulfate as the precipitant. the crystals were found to belong to the space group p2(1)2(1)2(1), having unit cell dimensions of a = 106.1 a, b = 126.1 a, and c = 57.7 a. the crystals diffracted x-rays at greater than 3.0 a resolution. | 1994 | 7896754 |
| oxidation of hydroxylamine by cytochrome p-460 of the obligate methylotroph methylococcus capsulatus bath. | an enzyme capable of the oxidation of hydroxylamine to nitrite was isolated from the obligate methylotroph methylococcus capsulatus bath. the absorption spectra in cell extracts, electron paramagnetic resonance spectra, molecular weight, covalent attachment of heme group to polypeptide, and enzymatic activities suggest that the enzyme is similar to cytochrome p-460, a novel iron-containing protein previously observed only in nitrosomonas europaea. the native and subunit molecular masses of the m ... | 1994 | 7928947 |
| the primary structure of cytochrome p460 of nitrosomonas europaea: presence of a c-heme binding motif. | cytochrome p460 and hydroxyamine oxidoreductase of nitrosomonas europaea both catalyze the oxidation of hydroxylamine and contain a 460 nm-absorbing chromophore. the gene (cyp) encoding cytochrome p460 was cloned and sequenced. the predicted amino acid sequence contains a single c-heme binding motif (cxxch) near the carboxy-terminus. cytochrome p460 shows little sequence homology to other c-cytochromes including hydroxyamine oxidoreductase. the presence of a signal peptide and a possible c-heme ... | 1994 | 7957885 |
| evolutionary relationships among ammonia- and nitrite-oxidizing bacteria. | comparative 16s rrna sequencing was used to evaluate phylogenetic relationships among selected strains of ammonia- and nitrite-oxidizing bacteria. all characterized strains were shown to be affiliated with the proteobacteria. the study extended recent 16s rrna-based studies of phylogenetic diversity among nitrifiers by the comparison of eight strains of the genus nitrobacter and representatives of the genera nitrospira and nitrospina. the later genera were shown to be affiliated with the delta s ... | 1994 | 7961414 |
| sequence of the gene, amob, for the 43-kda polypeptide of ammonia monoxygenase of nitrosomonas europaea. | the sequence for the 3' portion of amob, a gene encoding a 43-kda polypeptide component ammonia monooxygenase of nitrosomonas europaea, is presented. the derived polypeptide has no homology with other known proteins. amoa and amob are the only open reading frames in the putative amo operon. | 1994 | 7980540 |
| detection of nitrosomonas spp. by polymerase chain reaction. | a unique genomic dna fragment was isolated from nitrosomonas europaea atcc 19718. based on the sequence of this fragment, oligonucleotide primers for polymerase chain reaction amplification were prepared which amplify sequences of 775 and 658 bp. the predicted dna fragments were both amplified from the genome of n. europaea and a nitrosomonas spp. isolated from a local oxidation pond. the primers failed to amplify dna from the genomes of the ammonia oxidiser nitrosolobous multiformis, the nitrit ... | 1994 | 8056290 |
| sequence of hcy, a gene encoding cytochrome c-554 from nitrosomonas europaea. | cytochrome c-554 (cyt c-554) was purified from nitrosomonas europaea. the n-terminal and internal amino acid sequences were determined. a synthetic oligodeoxyribonucleotide primer based on the n-terminal sequence was used to construct a pcr clone. this clone was used to identify genomic dna fragments containing the gene encoding cyt c-554. we determined the nucleotide sequence of this gene and named it hcy for hydroxylamine oxidoreductase-linked cytochrome. | 1994 | 8063110 |
| effects of herbicides and fumigants on microbial activities in soil. | | 1994 | 8069060 |
| molecular analysis of enrichment cultures of marine ammonia oxidisers. | marine ammonia oxidising bacteria were enriched by incubation of sea water, amended with ammonium sulphate, and subsequent subculture in liquid inorganic medium. pcr primers were designed to be specific for rdna sequences from ammonia oxidisers belonging to the beta-sub-group of the proteobacteria. these primers were then used to amplify rrna genes from ammonia oxidiser enrichment cultures containing heterotrophs. pcr products were recovered from all cultures in which complete ammonia oxidation ... | 1994 | 8076810 |
| oxidation of methyl fluoride and dimethyl ether by ammonia monooxygenase in nitrosomonas europaea. | methyl fluoride and dimethyl ether were previously identified as inhibitors of ammonia oxidation and n2o production in autotrophic nitrifying bacteria. we demonstrate that methyl fluoride and dimethyl ether are substrates for ammonia monooxygenase and are converted to formaldehyde and a mixture of methanol and formaldehyde, respectively. | 1994 | 8085841 |
| identification of axial ligands of cytochrome c552 from nitrosomonas europaea. | cytochrome c552 from nitrosomonas europaea was analyzed by visible, epr and mcd spectroscopies. the visible and mcd data show that histidine and methionine are the axial ligands to the heme iron of the ferric protein. the epr spectrum of the cytochrome shows an atypical highly axial low spin (hals) type signal with g-values that make it difficult to identify the axial ligands. these results reinforce the value of near-infrared mcd spectroscopy for assigning ligands in ferric heme systems and poi ... | 1994 | 8143881 |
| biological nitrogen removal from wastewater. | a review of the research on the kinetics of nitrification and denitrification is presented including an explanation of reaction engineering models. the results of laboratory scale experiments with high rate nitrification processes are discussed using kinetic results for oxygen limitation as well as for substrate limitation and inhibition. it can be demonstrated that reaction engineering models are helpful for a better understanding of the processes and for the design of reactors. pilot scale inv ... | 1994 | 8165950 |
| organization of the hao gene cluster of nitrosomonas europaea: genes for two tetraheme c cytochromes. | the organization of genes for three proteins involved in ammonia oxidation in nitrosomonas europaea has been investigated. the amino acid sequence of the n-terminal region and four heme-containing peptides produced by proteolysis of the tetraheme cytochrome c554 of n. europaea were determined by edman degradation. the gene (cyca) encoding this cytochrome is present in three copies per genome (h. mctavish, f. laquier, d. arciero, m. logan, g. mundfrom, j.a. fuchs, and a. b. hooper, j. bacteriol. ... | 1994 | 8195067 |
| a comparison of no and n2o production by the autotrophic nitrifier nitrosomonas europaea and the heterotrophic nitrifier alcaligenes faecalis. | soil microorganisms are important sources of the nitrogen trace gases no and n2o for the atmosphere. present evidence suggests that autotrophic nitrifiers such as nitrosomonas europaea are the primary producers of no and n2o in aerobic soils, whereas denitrifiers such as pseudomonas spp. or alcaligenes spp. are responsible for most of the no and n2o emissions from anaerobic soils. it has been shown that alcaligenes faecalis, a bacterium common in both soil and water, is capable of concomitant he ... | 1993 | 8285659 |
| reductive dehalogenation of the trichloromethyl group of nitrapyrin by the ammonia-oxidizing bacterium nitrosomonas europaea. | suspensions of nitrosomonas europaea catalyzed the reductive dehalogenation of the commercial nitrification inhibitor nitrapyrin (2-chloro-6-trichloromethylpyridine). the product of the reaction was identified as 2-chloro-6-dichloromethylpyridine by its mass fragmentation and nuclear magnetic resonance spectra. a small amount of 2-chloro-6-dichloromethylpyridine accumulated during the conversion of nitrapyrin to 6-chloropicolinic acid in an aerated solution in the presence of ammonia (t. vannell ... | 1993 | 8285668 |
| characterization of the gene encoding hydroxylamine oxidoreductase in nitrosomonas europaea. | hydroxylamine oxidoreductase (hao) catalyzes the oxidation of hydroxylamine to nitrite in nitrosomonas europaea. the electrons released in the reaction are partitioned to ammonium monooxygenase and to the respiratory chain. the immediate acceptor of electrons from hao is believed to be cytochrome c-554 (cyt c-554). we have isolated a genomic dna fragment containing the structural gene encoding hao (hao) and a part of the gene for cyt c-554. the nucleotide sequence of hao was determined, and its ... | 1994 | 8288544 |
| roles of bovine serum albumin and copper in the assay and stability of ammonia monooxygenase activity in vitro. | we investigated the effects of bovine serum albumin (bsa) on both the assay and the stability of ammonia-oxidizing activity in cell extracts of nitrosomonas europaea. ammonia-dependent o2 uptake activity of freshly prepared extracts did not require bsa. however, a dependence on bsa developed in extracts within a short time. the role of bsa in the assay of ammonia-oxidizing activity apparently is to absorb endogenous free fatty acids which are present in the extracts, because (i) only proteins wh ... | 1995 | 7665467 |
| effects of ammonia on the de novo synthesis of polypeptides in cells of nitrosomonas europaea denied ammonia as an energy source. | the effects of ammonium on the de novo synthesis of polypeptides in the soil-nitrifying bacterium nitrosomonas europaea have been investigated. cells were incubated in the presence of both acetylene and nh4+. under these conditions, the cells were unable to utilize nh4+ as an energy source. energy to support protein synthesis was supplied by the oxidation of hydroxylamine or other alternative substrates for hydroxylamine oxidoreductase. de novo protein synthesis was detected by 14c incorporation ... | 1995 | 7665474 |