Publications

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
phosphate requirements of the nitrifying bacteria.		1967	5299910
effect of chloride on oxidation of hydroxylamine by nitrosomonas europaea cells.		1968	5636823
inhibition of nitrifying chemolithotrophic bacteria by several insecticides.		1968	5636842
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
microbial formation of nitrite in ventilating shafts.		1968	5690682
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
isolation of ammonia-oxidizing autotrophic bacteria.		1968	4883087
growth of nitrosomonas europaea in batch and in continuous culture.		1968	4884200
calorimetric measurement of free energy utilization by nitrosomonas and nitrobacter.		1968	4885091
energy-coupling mechanisms in chemolithotrophic bacteria.		1968	4972376
a nitrite-reducing enzyme from nitrosomonas europaea. preliminary characterization with hydroxylamine ad electron donor.		1968	4298926
properties of some reductase enzymes in the nitrifying bacteria and their relationship to the oxidase systems.	the reductase enzymes in nitrosomonas and nitrobacter were studied under anaerobic conditions when the oxidase enzymes were inactive. the most effective electron-donor systems for nitrate reductase in nitrobacter were reduced benzyl viologen alone, phenazine methosulphate with either nadh or nadph, and fmn or fad with nadh. nitrite and hydroxylamine reductases were found in both nitrifying bacteria, and optimum activity for each enzyme was obtained with nadh or nadph with either fmn or fad. the ...	1968	4386932
glutamate dehydrogenase in nitrosomon as europaea and the effect of hydroxylamine, oximes and related compounds on its activity.		1969	4388079
biochemical basis of obligate autotrophy in nitrosomonas europaea.	the specific activities of isocitric dehydrogenase, alpha-ketoglutaric dehydrogenase, succinic dehydrogenase, malic dehydrogenase, and reduced nicotinamide adenine dinucleotide (nadh) oxidase were determined in extracts of nitrosomonas europaea and compared with the corresponding values for anacystis nidulans and autotrophically grown hydrogenomonas eutropha. in common with other obligate autotrophs and in contrast to facultative autotrophs, nitrosomonas extracts lacked alpha-ketoglutaric dehydr ...	1969	4304222
the biochemistry of nitrifying microorganisms.		1969	4893925
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
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
persistence and effects of some chlorinated anilines on nitrification in soil.		1969	5796122
inhibition of nitrifying bacteria by grass and forb root extracts.		1969	5798521
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
effect of mixing on the washout and steady-state performance of continuous cultures.		1970	4950531
products of sulphide oxidation in extracts of thiobacillus concretivorus.		1970	5416105
mathematical models as an aid in the solution of water pollution control problems.		1970	5419436
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
intermediary metabolism of carbon compounds by nitrifying bacteria.		1970	5426270
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
studies on the incorporation of labelled sulphate into cells and cell-free extracts of nitrosomonas europaea.		1970	4991964
[effect of light on the metabolism of non-photosynthesizing microorganisms].		1971	4935598
presence and function of disclinations in surface coats of unicellular organisms.		1971	4938847
comparison of the morphology and deoxyribonucleic acid composition of 27 strains of nitrifying bacteria.	the gross morphology, fine structure, and per cent guanine plus cytosine (gc) composition of deoxyribonucleic acid of 27 strains of nitrifying bacteria were compared. based on morphological differences, the ammonia-oxidizing bacteria were separated into four genera. nitrosomonas species and nitrosocystis species formed one homogenous group, and nitrosolobus species and nitrosospira species formed a second homogenous group in respect to their deoxyribonucleic acid gc compositions. similarly, the ...	1971	4939767
the scope of the eater pollution problem.		1971	5161226
the antibacterial effect of dry tomato plants, onion peels, and guava leaves on soil microorganisms.		1971	5172508
purification and properties of atp-sulphurylase from nitrobacter agilis.		1971	4323859
the microbial ecology of the activated sludge process.		1971	4347114
electron transport systems of nitrosomonas: isolation of a membrane-envelope fraction.	freezing and thawing of nitrosomonas, followed by centrifugation of the homogenate at 3,000 x g, resulted in a fraction which appeared to consist of an intact membrane-envelope complex and contained approximately 50% of the cell protein and more than 90% of the ubiquinone and cytochrome a-type mammalian cytochrome c oxidase activity. the supernatant fraction, resulting from subsequent centrifugation of the extract at 100,000 x g, contained approximately 50% of the cell protein and more than 80% ...	1972	4336111
ultrastructure of nitrosomonas europaea cells as revealed by freeze-etching.		1972	4337054
solubilization and purification of cytochrome 1 from nitrosomonas.		1972	4345284
growth of mixed cultures of autotrophic and heterotrophic organisms.		1972	4622985
absorption bands of multiple b and c cytochromes in bacteria detected by numerical analysis of absorption spectra.		1972	4625502
[determination of the activity of nitrifying bacteria in surface waters by a modified bod-test].		1972	4660907
growth of obligate autotrophic bacteria on glucose in a continuous flow-through apparatus.	nitrosomonas europaea, nitrobacter agilis, thiobacillus denitrificans, t. neapolitanus, and t. thioparus (all obligate autotrophic bacteria) have been grown in dialysis culture, on glucose salts media, in the absence of their specific inorganic energy source. metabolic products for n. agilis grown on nitrite salts medium were identified as keto acids. pyruvic acid inhibited this organism at 5 x 10(-5)m. keto acids were not inhibitory for the thiobacilli grown on thiosulfate medium. however, when ...	1972	4551747
phosphoenolpyruvate carboxylase of thiobacillus thiooxidans. kinetic and metabolic control properties.		1972	4552310
identification of the sources of nitrous oxide produced by oxidative and reductive processes in nitrosomonas europaea.	1. cells of nitrosomonas europaea produced n(2)o during the oxidation of ammonia and hydroxylamine. 2. the end-product of ammonia oxidation, nitrite, was the predominant source of n(2)o in cells. 3. cells also produced n(2)o, but not n(2) gas, by the reduction of nitrite under anaerobic conditions. 4. hydroxylamine was oxidized by cell-free extracts to yield nitrite and n(2)o aerobically, but to yield n(2)o and no anaerobically. 5. cell extracts reduced nitrite both aerobically and anaerobically ...	1972	5073730
[microbial ecology of moroccari soils. i. seasonal fluctuations].		1972	5077031
preliminary characterization of a variant co-binding heme protein from nitrosomonas.		1972	5077861
metabolism of inorganic nitrogen compounds in plants and micro-organisms.		1972	5085571
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
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
purification of c-type cytochromes from nitrosomonas europaea.		1973	4352494
photoinactivation of ammonia oxidation in nitrosomonas.	photoinactivation of ammonia oxidation in cells of nitrosomonas was shown to follow first-order kinetics with a rate constant proportional to incident light intensity. the action spectrum for photoinactivation consisted of a broad peak in the ultraviolet range, where both hydroxylamine and ammonia oxidation were affected, and a shoulder at approximately 410 nm where only ammonia oxidation was affected. in photoinactivated cells, hydroxylamine but not ammonia was oxidized to nitrite and hydroxyla ...	1974	4369012
cytochrome c-552 and cytochrome c-554 derived from nitrosomonas europaea. purification, properties, and their function in hydroxylamine oxidation.		1974	4372235
eukaryotic cytochrome c-like properties of cytochrome c-550 (thiobacillus novellus).		1974	4373290
ammonia or ammonium ion as substrate for oxidation by nitrosomonas europaea cells and extracts.	the effect of ph on the k(m) values for ammonia was studied in its oxidation by nitrosomonas cells and cell-free extracts. the k(m) values decreased markedly with increasing ph, suggesting (nh(3)) rather than (nh(4) (+)) as the actual substrate for oxidation.	1974	4422399
[the effect of temperature on the rat of oxidation of ammonia to nitrate by mixed cultures of nitrifying organisms (author's transl)].		1974	4468751
the partial characterization of purified nitrite reductase and hydroxylamine oxidase from nitrosomonas europaea.	nitrite reductase has been separated from cell-free extracts of nitrosomonas and partially purified from hydroxylamine oxidase by polyacrylamide-gel electrophoresis. in its oxidized state the enzyme, which did not contain haem, had an extinction maximum at 590nm, which was abolished on reduction. sodium diethyldithiocarbamate was a potent inhibitor of nitrite reductase. enzyme activity was stimulated 2.5-fold when remixed with hydroxylamine oxidase, but was unaffected by mammalian cytochrome c. ...	1974	4154745
mechanisms of inorganic oxidation and energy coupling.		1974	4215368
autecological study of the chemoautotroph nitrobacter by immunofluorescence.	fluorescent antibodies (fa) prepared for nitrobacter agilis and n. winogradskyi were highly reactive in homologous staining. low-level cross-reactions between the two species were removed by adsorption. all 15 pure-culture isolates of nitrobacter tested reacted strongly with either n. agilis fa or n. winogradskyi fa. all pure-culture isolates from soils were determined to be n. winogradskyi; those from mammoth cave sediments and a cattle waste oxidation ditch were n. agilis. no cross-reaction wa ...	1974	4589121
[effect of fertilizers on the number of bacteria involved in the turnover of nitrogen in pond water of the astrakhan region].	the type of intensification affects the distribution of bacteria involved in turnover of nitrogen in pond water. green fertilizers (reed) stimulate the number of nitrogen-fixing bacteria, and the number and activity of nitrifying bacteria, to a higher degree than nitrogen and phosphorus fertilizers. reed is recommended as the main means for intensification of spawning ponds of the astrakhan region.	1976	137355
[oxidation of inorganic compound by autotrophic bacteria (author's transl)].		1976	184217
the effect of ph and partial pressure of oxygen on nitrification (author's transl).	a mathematical model which describes the effect of ph and dissolved oxygen on growth and activity of nitrosomonas and nitrobacter in mixed culture is presented. a good fit is obtained between experimental data and theoretical curves computed with parameters estimated by independent methods. experimental data together with simulation studies show that inadequate aeration induces a temporal shift of ammonium and nitrite oxidations resulting in a transient nitrite accumulation similar to that cause ...	1976	7988
energy coupling and respiration in nitrosomonas europaea.	intact cells of nitrosomonas europaea grown in an ammonium salts medium will oxidise ammonium ions, hydroxylamine and ascorbate-tmpd; there is no oxidation of carbon monoxide, methane or methanol. the km value for ammonia oxidation is highly ph dependent with a minimum value of 0.5 mm above ph 8.0. this suggests that free ammonia is the species crossing the cytoplasmic membrane(s). the measurement of respiration driven proton translocation indicates that there is probably only one proton translo ...	1976	13754
[comparative biochemistry of dissimilatory nitrite reductases (author's transl)].		1976	818322
[thermophilic nitrifying bacteria from hot springs].	a culture of thermophilic nitrifying bacteria was isolated from geothermal springs of kamchatka (50-86 degrees c, ph 6.3-7.5) and tajig ssr (50-85 degrees c, ph 7.3-8.5). the culture oxidizes ammonium nitrogen at 40-70 degrees c. it resembles nitrosomonas europea winogradskyi by its morphology. dimensions of the cells vary within 0.7-0.9 x 0.8-1.4 mcm. each cell has a polar flagellum whose diameter is about 140 a. this is the first description of thermophilic nitrifying bacteria belonging to the ...	1976	933875
in situ morphology of nitrifying-like bacteria in aquaculture systems.	the in situ microbiota from several aquaculture facilities with active nitrification was examined by transmission electron microscopy of thin sections for the presence of bacteria that contained intracytoplasmic membranes characteristic of the nitrifying bacteria. colonies of bacteria with the cellular morphology of a species of nitrosomonas were found to be present in both the culture water and in the biological filter slime of a freshwater chinook salmon (oncorhynchus tshawytscha) culture syst ...	1976	938036
an automated biological nitrification toxicity test.		1976	994305
competitive inhibition of ammonia oxidation in nitrosomonas europaea by methane, carbon monoxide or methanol.		1976	1001454
hydroxylamine oxidoreductase from nitrosomonas: inactivation by hydrogen peroxide.	incubation of hydroxylamine oxidoreductase of nitrosomonas with hydrogen peroxide resulted in the rapid and irreversible loss of the ability to catalyze the dehydrogenation of hydroxylamine in the presence of electron acceptors, such as phenazine methosulfate. the rate of the reaction was dependent on the concentration of enzyme and h2o2. inactivation occurred most rapidly at ph values between 9 and 10. inactivation of the enzyme by h2o2 did not result in alteration of absorption spectrum of eit ...	1977	836796
nitrification in histosols: a potential role for the heterotrophic nitrifier.	insufficient populations of nitrosomonas and nitrobacter were found in a pahokee muck soil (lithic medidaprit) to account for the nitrate concentration observed. to determine if heterotrophic nitrifiers could account for some of this discrepancy, a method was developed to measure the levels of heterotrophic nitrifiers in soil. a population of 4.1 x 10(5) arthrobacter per g of dry fallow soil, capable of producing nitrite and/or nitrate from reduced nitrogenous compounds, was observed. amendment ...	1977	869537
nitrification in the intertidal zone: influence of effluent type and effect of tannin on nitrifiers.	nitrification by intertidal sediments was measured by using a tide simulator that approximated the cycle of seawater on tidal flats. sediments were chosen from sites affected by industrial and municipal effluents and pastoral seepage and runoff. the ability of sediments from different sites to nitrify endogenous nitrogen varied markedly. all sites exhibited an initial lag before activity commenced. the duration of this lag and the rate of nitrate production were different at each site. the sedim ...	1977	931375
the influence of some herbicides on selected groups of microorganisms in loess and sandy soils. ii. the effect of nitrification.	studies on the effect of herbicides on nitrification in field and laboratory conditions have shown that steady use of these substances in the same field does not exert a significant effect on this process in the soil. the herbicides caused only shortlasting disturbances. nitrification usually returned to a relative equilibrium in several days after the herbicide application.	1977	67749
polyhedral inclusion bodies in cells of nitrosomonas spec.	polyhedral inclusion bodies were observed in cells of a nitrosomonas species. they were present in growing cells as well as in resting cells. in thin sections their size was about 130 nm in growing cells and about 185 nm in diameter in resting cells. the bodies were commonly located in the nucleoplasm. they appeared to be bounded by a nonunit membrane and had a granular substructure. in thin sections about 70% of the exponentially grown cells and about 20% of the resting cells of the investigate ...	1977	190964
[studies on some unusual c type cytochromes (author's transl)].		1977	193149
a comparison between nitrosomas europaea and thiobacillus novellus on the basis of their oxidation systems of inorganic compounds.	nitrosomonas europaea and thiobacillus novellus were compared with each other on the basis of the biochemical properties of their inorganic compound-oxidizing systems. cytochromes c of the two organisms differ considerably from each other; n. europaea cytochrome c-552 belongs to the "bacterial-type" cytochrome c, while t. nouellus cytochrome c-550 resembles eucaryolic cytochrome c. the specificity of cytochrome oxidase for cytochrome c as the electron donor is different between the two organism ...	1977	198039
hydroxylamine oxidoreductase of nitrosomonas. oxidation of diethyldithiocarbamate concomitant with stimulation of nitrite synthesis.		1977	199251
purification and some properties of cytochrome c-552 from an extreme thermophile, thermus thermophilus hb8.	a c-type cytochrome, cytochrome c-552, from a soluble fraction of an extreme thermophile, thermus thermophilus hb8, was highly purified and its properties investigated. the absorption peaks were at 552, 522, and 417 nm in the reduced form, and at 408 nm in the oxidized form. the isoelectric point was at ph 10.8, the midpoint redox potential was about +0.23 v, and the molecular weight was about 15,000. the cytochrome c-552 was highly thermoresistant. the cytochrome reacted rapidly with pseudomona ...	1977	199583
hydroxylamine oxidoreductase from nitrosomonas: absorption spectra and content of heme and metal.		1978	698180
purification of electron-transfer components of nitrifying and denitrifying bacteria and assay of intermediates.		1978	713858
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
highly purified hydroxylamine oxidoreductase derived from nitrosomonas europaea. some physicochemical and enzymatic properties.	hydroxylamine oxidoreductase [ec 1.7.3.4] of nitrosomonas europaea was purified to an electrophoretically homogeneous state and some of its properties were studied. the molecular weight of the enzyme as determined by gel filtration on sephadex g150 and by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate is 175,000-180,000, while the minimum molecular weight per heme determined from the dry weight and heme content is 17,500. the enzyme is a c-type cytochrome; its reduc ...	1979	227845
effect of benomyl and its hydrolysis products, mbc and ab, on nitrification in a flooded soil.		1979	444723
hydroxylamine oxidoreductase of nitrosomonas. production of nitric oxide from hydroxylamine.		1979	497235
stable isotope studies on the oxidation of ammonia to hydroxylamine by nitrosomonas europaea.		1979	499527
[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
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
preparation of membrane vesicles in lithium chloride from cells of nitrosomonas europaea.		1980	6261609
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
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