Antonie Van Leeuwenhoek, 1990 Nov, 58(4), 283 - 9 Bioenergetic examination of the heterotrophic nitrifier-denitrifier Thiosphaera pantotropha; Castignetti D; The heterotrophic nitrifying-denitrifying bacterium Thiosphaera pantotropha is remarkable as it nitrifies and denitrifies simultaneously . With respect to nitrogenous compounds, whether nitrification or denitrification results in energy conservation is of interest . Proton translocation studies were performed to determine if energy was conserved by the bacterium during heterotrophic nitrification and denitrification . Hydrazine (N2H5+) was employed as the heterotrophic nitrification substrate while nitrate, nitrite and nitrous oxide were used as denitrification substrates . Analysis of the data indicate that the bacterium does not conserve energy when hydrazine was the substrate . Conversely, energy was conserved when either nitrate, nitrite or nitrous oxide functioned as the oxidants during denitrification-dependent proton translocation experiments . Thiosphaera pantotropha thus is similar to other heterotrophic nitrifiers-denitrifiers in that it conserves energy while denitrifying but has not been observed to do so when heterotrophically nitrifying. J Bacteriol, 1990 Sep, 172(9), 5368 - 73 Oxidation of monohalogenated ethanes and n-chlorinated alkanes by whole cells of Nitrosomonas europaea; Rasche ME et al.; We have investigated the substrate specificity of ammonia monooxygenase in whole cells of the nitrifying bacterium Nitrosomonas europaea for a number of aliphatic halogenated hydrocarbons . To determine the effect of the halogen substituent and carbon chain length on substrate reactivity, we measured the rates of oxidation of the monohalogenated ethanes (fluoroethane, chloroethane, bromoethane, and iodoethane) and n-chlorinated C1 to C4 alkanes by whole cells of N . europaea . For monohalogenated ethanes, acetaldehyde was the major organic product and little or none of any of the alternate predicted products (2-halogenated alcohols) were detected . The maximum rate of haloethane oxidation increased with decreasing halogen molecular weight from iodoethane to chloroethane (19 to 221 nmol/min per mg of protein) . In addition, the amount of substrate required for the highest rate of haloethane oxidation increased with decreasing halogen molecular weight . For the n-chlorinated alkanes, the rate of dechlorination, as measured by the appearance of the corresponding aldehyde product, was greatest for chloroethane and decreased dramatically for chloropropane and chlorobutane (118, 4, and 8 nmol of aldehyde formed per min per mg of protein, respectively) . The concentration profiles for halocarbon oxidation by ammonia monooxygenase showed apparent substrate inhibition when ammonia was used as the reductant source . When hydrazine was used as the electron donor, no substrate inhibition was observed, suggesting that the inhibition resulted from reductant limitation. J Bacteriol, 1990 Sep, 172(9), 4775 - 82 Inhibition of ammonia monooxygenase in Nitrosomonas europaea by carbon disulfide; Hyman MR et al.; Carbon disulfide has long been recognized as a potent inhibitor of nitrification, and it is the likely active component in several nitrification inhibitors suitable for field use . The effects of this compound on Nitrosomonas europaea have been investigated, and the site of action has been determined . Low concentrations of CS2 (less than 400 microM) produced a time-dependent inhibition of ammonia-dependent O2 uptake but did not inhibit hydrazine-oxidizing activity . CS2 also produced distinct changes in difference spectra of whole cells . These results suggest that ammonia monooxygenase (AMO) is the site of action of CS2 . Unlike the case for thiourea and acetylene, saturating concentrations of CS2 did not fully inhibit AMO, and the inhibition resulted in a low but significant rate of ammonia-dependent O2 uptake . The effects of CS2 were not competitive with respect to ammonia concentration, and the inhibition by CS2 did not require the turnover of AMO to take effect . The ability of CS2-treated cells to incorporate {14C}acetylene into the 28-kilodalton polypeptide of AMO was used to demonstrate that the effects of CS2 are compatible with a mode of action which involves a reduction of the rate of turnover of AMO without effects on the catalytic mechanism . It is proposed that CS2 may act on AMO by reversibly reacting with a suitable nucleophilic amino acid in close proximity to the active site copper. Appl Environ Microbiol, 1990 Aug, 56(8), 2430 - 5 Detection and analysis of two serotypes of ammonia-oxidizing bacteria in sewage plants by flow cytometry; Volsch A et al.; Two different serotypes of the genus Nitrosomonas were isolated from samples of the sewage plant Heidelberg . These nitrifiers were enumerated in activated sludge of various other sewage plants after immunofluorescent labeling and staining with propidium iodide by flow cytometry . The concentrations of these serotypes of Nitrosomonas spp . were in the range of 0.1 to 2% . Also, a test for the determination of the activity of ammonia-oxidizing bacteria was developed . Nitrite-oxidizing bacteria were specifically inhibited with sodium chlorate, and the activity of ammonia-oxidizing bacteria could be calculated from the increase of nitrite . Concentrations and activities of ammonia oxidizers were measured for a period of 6 months in the sewage plant Heidelberg . With one exception, activities and concentrations of ammonia-oxidizing bacteria decreased and increased in parallel. Rev Argent Microbiol, 1990 Jul-Sep, 22(3), 146 - 9 {Complete nitrification in soil columns perfused with nitrite}; Marengo GW et al.; Four columns of the same soil were put under the continuous flow of a NaNO2 solution {50 ppm N}, so as to follow the evolution of nitrification . The soil, the columns as well as the solution continuous flow regulating system, were prepared as in the previous experiments . The columns, with the exception of No1 (control), contained also the following substances: No2 and 4: 2% de CaCO3 and No3 and 4:0.0015% SO - 4-S . Since the eight day of perfusion all the effluents had an important concentration of nitrate (Figure 1), exceeding in them, the sum of {No-2-N} an {NO-3-N} (Table 1) the concentration of th NO-2-N of the perfusion solution . Finally, the {NO-2-N} was reduced importantly in the effluents, and the (NO-3N), in all of them, stabilized itself as values nearing 50 ppm . Its suggested that at the beginning of the experiment, an endogenous source of NO-2 was functioning, which could explain the observed phenomenon, and that later it ceased to do so . The populational density of NO-2 oxidizers increased, during the experiment, 49 times (Table 2) . An increase was also measured in the populational density of NH+4 oxidizers, which amounted to 41 times . This later fact contributes to support the existence of an endogenous provision of NO-2 during the initial part of the experiment. Zentralbl Hyg Umweltmed, 1990 May, 190(1-2), 117 - 26 {Examination of sewage for nitrification inhibitors with the help of a simple and accessible bioassay}; Otremba H et al.; The biotest presented permits the investigation of sewage as for the presence of nitrification-inhibiting substances . A waste-water sample has to be aerated together with activated sludge for 5 h . The concentration of ammonia and nitrate will be analysed at the beginning and the end of the test . The intensity of nitrification can be detected comparing the increase of nitrate in the sewage sample with a control . In order to verify the reliance of the test the effect of different parameters on the test system like pH, BOD of the sludge, content of ammonia, nitrite and nitrate and different sewage-relevant compounds were investigated . The biotest was successfully applied in order to find out the inhibition of nitrification in a communal purification plant . An emission of nitrification inhibiting substances was determined by screening of the supplies of the purification plant. Can J Microbiol, 1990 Apr, 36(4), 273 - 8 Nitrification of swine waste; Blouin M et al.; Complete oxidation of ammonia nitrogen (approximately 1000 mg/L) to nitrite was observed in stabilized swine waste after 49 days in incubation at 400 rpm and 29 degrees C, only if 10% (v/v) activated sludge from a wastewater treatment unit and 1.5% (w/v) CaCO3, were added . Stabilized swine waste contains less than 0.09 most probable number (MPN) per millilitre of nitrosobacteria and 2.3 MPN/mL of nitrobacteria . In activated sludge, the concentrations of these bacteria were 2.4 MPN/mL for nitrosobacteria and 4.2 x 10(5) MPN/mL for nitrobacteria . In the swine waste where ammonia was oxidized to nitrite, the nitrosobacteria growth increased to 5.5 x 10(5) MPN/mL, while the nitrobacteria growth decreased to 2.3 MPN/mL . Inoculation of a freshly stabilized swine waste with 10% (v/v) of the active nitrifying waste and addition of 1.5% (w/v) CaCO3, accelerated the oxidation of ammonia nitrogen to nitrite; the reaction was completed after only 5 days of incubation . Increasing the incubation period to 10 days resulted in the complete oxidation of the accumulated nitrite to nitrate . In the stabilized swine waste, complete nitrification without accumulation of nitrite was obtained in only 5 days of incubation when the waste was inoculated with both enriched nitrifying populations (10(6)-10(7) MPN/mL). Appl Environ Microbiol, 1990 Apr, 56(4), 1169 - 71 Degradation of halogenated aliphatic compounds by the ammonia- oxidizing bacterium Nitrosomonas europaea; Vannelli T et al.; Suspensions of Nitrosomonas europaea catalyzed the ammonia-stimulated aerobic transformation of the halogenated aliphatic compounds dichloromethane, dibromomethane, trichloromethane (chloroform), bromoethane, 1,2-dibromoethane (ethylene dibromide), 1,1,2-trichloroethane, 1,1,1-trichloroethane, monochloroethylene (vinyl chloride), gem-dichloroethylene, cis- and trans-dichloroethylene, cis-dibromoethylene, trichloroethylene, and 1,2,3-trichloropropane, Tetrachloromethane (carbon tetrachloride), tetrachloroethylene (perchloroethylene), and trans-dibromoethylene were not degraded. Antonie Van Leeuwenhoek, 1990 Apr, 57(3), 139 - 52 Combined heterotrophic nitrification and aerobic denitrification in Thiosphaera pantotropha and other bacteria; Robertson LA et al.; Reports of the simultaneous use of oxygen and denitrification by different species of bacteria have become more common over the past few years . Research with some strains (e.g . Thiosphaera pantotropha) has indicated that there might be a link between this 'aerobic denitrification' and a form of nitrification which requires rather than generates energy and is therefore known as heterotrophic nitrification . This paper reviews recent research into heterotrophic nitrification and aerobic denitrification, and presents a preliminary model which, if verified, will provide at least a partial explanation for the simultaneous occurrence of nitrification and denitrification in some bacteria. Appl Environ Microbiol, 1990 Feb, 56(2), 451 - 62 Ammonia-oxidizing bacteria in a chloraminated distribution system: seasonal occurrence, distribution and disinfection resistance; Wolfe RL et al.; Nitrification in chloraminated drinking water can have a number of adverse effects on water quality, including a loss of total chlorine and ammonia-N and an increase in the concentration of heterotrophic plate count bacteria and nitrite . To understand how nitrification develops, a study was conducted to examine the factors that influence the occurrence of ammonia-oxidizing bacteria (AOB) in a chloraminated distribution system . Samples were collected over an 18-month period from a raw-water source, a conventional treatment plant effluent, and two covered, finished-water reservoirs that previously experienced nitrification episodes . Sediment and biofilm samples were collected from the interior wall surfaces of two finished-water pipelines and one of the covered reservoirs . The AOB were enumerated by a most-probable-number technique, and isolates were isolated and identified . The resistance of naturally occurring AOB to chloramines and free chlorine was also examined . The results of the monitoring program indicated that the levels of AOB, identified as members of the genus Nitrosomonas, were seasonally dependent in both source and finished waters, with the highest levels observed in the warm summer months . The concentrations of AOB in the two reservoirs, both of which have floating covers made of synthetic rubber (Hypalon; E.I . du Pont de Nemours & Co., Inc., Wilmington, Del.), had most probable numbers that ranged from less than 0.2 to greater than 300/ml and correlated significantly with temperature and levels of heterotrophic plate count bacteria . No AOB were detected in the chloraminated reservoirs when the water temperature was below 16 to 18 degrees C . The study indicated that nitrifiers occur throughout the chloraminated distribution system . Higher concentrations of AOB were found in the reservoir and pipe sediment materials than in the pipe biofilm samples . The AOB were approximately 13 times more resistant to monochloramine than to free chlorine . After 33 min of exposure to 1.0 mg of monochloramine per liter (pH 8.2, 23 degrees C), 99% of an AOB culture was inactivated . The amounts of this disinfectant that are currently used (1.5 mg/liter at a 3:1 ratio of chlorine to ammonia-N) may be inadequate to control the growth of these organisms in the distribution system. Biol Met, 1990, 3(3-4), 197 - 203 The catabolism and heterotrophic nitrification of the siderophore deferrioxamine B; Castignetti D et al.; Three bacteria, two of which were previously noted as active heterotrophic nitrifiers, were examined for their ability to grow and nitrify with the siderophore deferrioxamine B as the carbon source . Pseudomonas aureofaciens displayed limited growth and nitrification while a heterotrophic nitrifying Alcaligenes sp . was without action concerning its metabolism of deferrioxamine B . The third bacterium, a unique Gram-negative soil isolate, was unable to nitrify deferrioxamine B but grew well when the siderophore was employed as the sole C source . The Gram-negative bacterium removed deferrioxamine B from the medium and left only residual amounts of the compound in solution at the termination of its growth . The organism was without action when the ferrated analogue of deferrioxamine B, ferrioxamine B, served as either the C source for growth, for metabolism by resting cells, or as the substrate for cell-free extracts . Deferrioxamine B, by contrast, was rapidly metabolized by resting cells . Cell-free extracts of the bacterium synthesized a monohydroxamate(s) when deferrioxamine B was the substrate . The catabolism of deferrioxamine B, which is synthesized by soil microbes, suggests that soil microflora have the ability to return deferrioxamine B, and perhaps other, siderophores to the C cycle. Antonie Van Leeuwenhoek, 1989 Nov, 56(4), 289 - 99 Aerobic denitrification in various heterotrophic nitrifiers; Robertson LA et al.; Various heterotrophic nitrifiers have been tested and found to also be aerobic denitrifiers . The simultaneous use of two electron acceptors (oxygen and nitrate) permits these organisms to grow more rapidly than on either single electron acceptor, but generally results in a lower yield than is obtained on oxygen, alone . One strain, formerly known as "Pseudomonas denitrificans", was grown in the chemostat and shown to achieve nitrification rates of up to 44 nmol NH3 min-1 mg protein-1 and denitrification rates up to 69 nmol NO3(-1) min-1 mg protein-1 . Unlike Thiosphaera pantotropha, this strain needed to induce its nitrate reductase . However, the remainder of the denitrifying pathway was constitutive and, like T . pantotropha, "Ps . denitrificans" probably possesses the copper nitrite reductase. Antonie Van Leeuwenhoek, 1989 Nov, 56(4), 301 - 9 The effect of thiosulphate and other inhibitors of autotrophic nitrification on heterotrophic nitrifiers; Robertson LA et al.; It has been found that heterotrophic nitrification by Thiosphaera pantotropha can be inhibited by thiosulphate in batch and chemostat cultures . Allythiourea and nitrapyrin, both classically considered to be specific inhibitors of autotrophic nitrification, inhibited nitrification by Tsa . pantotropha in short-term experiments with resting cell suspensions . Hydroxylamine inhibited ammonia oxidation in chemostat cultures, but was itself fully oxidized . Thus the total nitrification rate for the culture remained the same . Heterotrophic nitrification by another organism, a strain of "Pseudomonas denitrificans" has also been shown to be inhibited by thiosulphate in short term experiments and in the chemostat . During these experiments it became evident that this strain is able to grow mixotrophically (with acetate) and autotrophically in a chemostat with thiosulphate as the energy source. Biochem Biophys Res Commun, 1989 Mar 15, 159(2), 640 - 3 Degradation of trichloroethylene by the ammonia-oxidizing bacterium Nitrosomonas europaea; Arciero D et al.; Suspensions of Nitrosomonas europaea are shown to cause the complete disappearance of 10 microM trichloroethylene at rates of 1 microM mg protein-1 . The reaction continues at nearly this rate for many hours . Fresh cells catalyze the reaction in the absence of added ammonium (presumably utilizing endogenous ammonia or stored reductant) . In older cells, trichloroethylene degradation depends on the addition of ammonia . Acetylene, 2-chloro 6-trichloromethylpyridine and alpha alpha'dipyridyl, which inhibit the oxidation of ammonia by cells, inhibit the degradation of trichloroethylene . Thus degradation of trichloroethylene is dependent on- and possibly catalyzed by the ammonia oxidizing enzyme. Microbiol Rev, 1989 Mar, 53(1), 68 - 84 Physiology, biochemistry, and specific inhibitors of CH4, NH4+, and CO oxidation by methanotrophs and nitrifiers; Bedard C et al.; Ammonia oxidizers (family Nitrobacteraceae) and methanotrophs (family Methylococcaceae) oxidize CO and CH4 to CO2 and NH4+ to NO2- . However, the relative contributions of the two groups of organisms to the metabolism of CO, CH4, and NH4+ in various environments are not known . In the ammonia oxidizers, ammonia monooxygenase, the enzyme responsible for the conversion of NH4+ to NH2OH, also catalyzes the oxidation of CH4 to CH3OH . Ammonia monooxygenase also mediates the transformation of CH3OH to CO2 and cell carbon, but the pathway by which this is done is not known . At least one species of ammonia oxidizer, Nitrosococcus oceanus, exhibits a Km for CH4 oxidation similar to that of methanotrophs . However, the highest rate of CH4 oxidation recorded in an ammonia oxidizer is still five times lower than rates in methanotrophs, and ammonia oxidizers are apparently unable to grow on CH4 . Methanotrophs oxidize NH4+ to NH2OH via methane monooxygenase and NH4+ to NH2OH via methane monooxygenase and NH2OH to NO2- via an NH2OH oxidase which may resemble the enzyme found in ammonia oxidizers . Maximum rates of NH4+ oxidation are considerably lower than in ammonia oxidizers, and the affinity for NH4+ is generally lower than in ammonia oxidizers . NH4+ does not apparently support growth in methanotrophs . Both ammonia monooxygenase and methane monooxygenase oxidize CO to CO2, but CO cannot support growth in either ammonia oxidizers or methanotrophs . These organisms have affinities for CO which are comparable to those for their growth substrates and often higher than those in carboxydobacteria . The methane monooxygenases of methanotrophs exist in two forms: a soluble form and a particulate form . The soluble form is well characterized and appears unrelated to the particulate . Ammonia monooxygenase and the particulate methane monooxygenase share a number of similarities . Both enzymes contain copper and are membrane bound . They oxidize a variety of inorganic and organic compounds, and their inhibitor profiles are similar . Inhibitors thought to be specific to ammonia oxidizers have been used in environmental studies of nitrification . However, almost all of the numerous compounds found to inhibit ammonia oxidizers also inhibit methanotrophs, and most of the inhibitors act upon the monooxygenases . Many probably exert their effect by chelating copper, which is essential to the proper functioning of some monooxygenases . The lack of inhibitors specific for one or the other of the two groups of bacteria hampers the determination of their relative roles in nature. J Biochem (Tokyo), 1989 Feb, 105(2), 245 - 8 Some properties of Nitrosomonas europaea cytochrome c oxidase (aa3-type) which lacks CuA; Numata M et al.; From Nitrosomonas europaea which had been cultivated in a medium deficient in copper, cytochrome c oxidase (aa3-type) which did not have CuA was purified . The oxidase did not show the 830-nm peak and its ESR spectrum differed greatly from that of the normal enzyme, which has two copper atoms, CuA and CuB, per molecule . However, the oxidase which did not have CuA showed almost the same cytochrome c oxidizing activity as the normal oxidase. Schriftenr Ver Wasser Boden Lufthyg, 1989, 80, 167 - 86 {Microbiologic studies of in situ removal of iron and manganese}; Schweisfurth R; While undoubtedly a good understanding of soil microbiology in terms of pedology exists, little is presently known about unsaturated subsoils, and aquifers . Yet, in the North German Basin, such underground environments contain to a 90 m depth up to 10(4) g-1 dry wt of heterotrophic bacteria, oligocarbophilic bacteria, denitrifying bacteria, nitrate reducing bacteria, iron precipitating and reducing bacteria, manganese oxidizing and reducing bacteria and other physiological groups of microorganisms . These bacteria are facultative anaerobes . When estimating microscopically, their counts reach up to 10(7) g-1 dry wt . In an oxygen free aquifer which received an oxygenated water for 10 years to remove iron and manganese, the counts of heterotrophic bacteria increased 1-2 orders of magnitude . The counts of nitrifying bacteria also increased whereas those of desulfurizers remained non-affected . In general, the oxidizing bacteria benefited more from the treatment than the reducing bacteria . The soil Eh value was increased, and BOD 5, 10 or 20 values were diminished in comparison to the oxygen free aquifer. FEMS Microbiol Rev, 1988 Dec, 4(4), 259 - 70 The nitrite oxidizing system of Nitrobacter winogradskyi; Yamanaka T et al.; Cytochrome components which participate in the oxidation of nitrite in Nitrobacter winogradskyi have been highly purified and their properties studied in detail . Cytochrome a1c1 is an iron-sulphur molybdoenzyme which has haems a and c and acts as a nitrite-cytochrome c oxidoreductase . Cytochrome c-550 is homologous to eukaryotic cytochrome c and acts as the electron mediator between cytochrome a1c1 and aa3-type cytochrome c oxidase . The oxidase is composed of two kinds of subunits, has two molecules of haem a and two atoms of copper in the molecule, and oxidizes actively eukaryotic ferrocytochrome c as well as its own ferrocytochrome c-550 . Further, a flavoenzyme has been obtained which has transhydrogenase activity and catalyses reduction of NADP+ with benzylviologen radical . This enzyme may be responsible for production of NADPH in N . winogradskyi . The electron transfer against redox potential from NO2- to cytochrome c could be pushed through prompt removal by cytochrome aa3 of H+ formed by the dehydrogenation of NO2- + H2O . As cytochrome c in anaerobically kept cell-free extracts is rapidly reduced on addition of NO2-, a membrane potential does not seem necessary for the reduction of cytochrome c by cytochrome a1c1 with NO2- in vivo. Eur J Biochem, 1988 Sep 15, 176(2), 273 - 9 Effect of solvent, pressure and temperature on reaction rates of the multiheme hydroxylamine oxidoreductase . Evidence for conformational change; Balny C et al.; Hydroxylamine oxidoreductase (HAO) of the ammonia-oxidizing bacterium Nitrosomonas catalyzes the oxidation: NH2OH + H2O----HNO2 + 2e- + 2 H+ . The heme-like chromophore P460 is part of a site which binds substrate, extracts electrons and then passes them to the many c hemes of the enzyme . Reduction of the c hemes by hydroxylamine is biphasic with apparent first-order rate constants k1 and k2 . CO binds to ferrous P460 with apparent first-order rate constants, k1,CO . In this work we have measured the binding of CO to ferrous P460 of hydroxylamine oxidoreductase and the reduction by substrate of some of the 24 c hemes of the ferric enzyme . These reactions have been studied in water and 40% ethylene glycol, at temperatures ranging from -15 degrees C to 20.7 degrees C and at hydrostatic pressures ranging over 0.1-80 MPa . From the measurements, thermodynamic parameters delta V+ (activation volume), delta G+, delta H+, and delta S+ have been calculated . CO binding . Binding of CO to ferrous P460 was similar to the binding of CO to ferrous horseradish peroxidase . The change of solvent had only a limited effect on delta V+ (-30 ml.mol-1), delta G+, delta H+ or delta S+ and did not cause an inflection in the Arrhenius plot or downward displacement of the linear relationship between ln k1,CO and P at a critical temperature . Binding was exothermic at high temperatures . The response of the binding of CO to solvent, temperature and pressure suggested that the CO binding site had little access to solvent and was not susceptible to change in protein conformation . Fast phase of reduction of c hemes . Changing the solvent from water to 40% ethylene glycol resulted in a decrease from 90% to 50% in the relative number of c hemes reduced during the fast phase, an increase in activation volume from -3.6 ml.mol-1 to 57 ml.mol-1 and changes in other thermodynamic parameters . The activation volume increased with decreasing temperature . The Arrhenius plot had a downward inflection at about 0 degrees C and, in water or ethylene glycol, the linear dependence of ln k1 on P was displaced downwards as the temperature changed from 3.5 degrees C to -15 degrees C . Slow phase of reduction of c hemes . Changing the solvent from water to 40% ethylene glycol resulted in an increase in the relative number of c hemes reduced during the slow phase from 10% to 50% . The activation volume, which was not measurable in water because of the low absorbance change, was -30 ml.mol-1 in ethylene glycol . The activation volume increased with increasing temperature.(ABSTRACT TRUNCATED AT 400 WORDS) FEMS Microbiol Rev, 1988 Apr-Jun, 4(2), 143 - 53 Different lipid A types in lipopolysaccharides of phototrophic and related non-phototrophic bacteria; Weckesser J et al.; Lipid A analyses confirm not only the present taxa of the purple nonsulfur bacteria (formerly Rhodospirillaceae), but also phylogenetical relatedness of distinct phototrophic to distinct non-phototrophic bacteria, as was suggested by cataloguing 16S rRNA . For example, lipid A with ester-bound 3-OH-10:0 and the rare amide-linked 3-oxo-14:0 is common to the phototrophic Rhodobacter capsulatus and Rhodobacter sphaeroides and also to Paracoccus denitrificans and Thiobacillus versutus . 'Lipid ADAG' (lipid A with 2,3-diamino-D-glucose (DAG)) occurs in the phototrophic Rhodopseudomonas viridis and Rhodopseudomonas palustris and also in the related non-phototrophic species, e.g., Nitrobacter winogradskyi, Pseudomonas diminuta, or Thiobacillus ferrooxidans . The phylogenetically more coherent purple sulfur bacteria (Chromatiaceae) uniformly contain D-mannose in their phosphate-free lipid A . Among the green bacteria, only the Chlorobiaceae but not the likewise chlorosome-containing Chloroflexaceae contain lipopolysaccharide . Lipid ADAG from R . viridis is a structural analogue of a biosynthetic precursor (lipid X) of enterobacterial lipid A . Lipid A synthase from Salmonella accepts not only lipid X but also the synthetic di-N-acyl-2,3-diamino-D-glucose analogue as substrate (Raetz, C.R.H., unpublished results) . More and more naturally occurring lipid A's with both, 2,3-diaminoglucose and glucosamine ('mixed' lipid A, with 2,3-diaminoglucose or glucosamine dominating) are being found . Newly recognized lipid A and lipid ADAG types might offer the possibility of differentially stimulating desired biological activities in animals without also having the undesired endotoxic activities . The non-toxic lipid A from Rhodopseudomonas viridis for example is able to stimulate prostaglandin secretion in peritoneal macrophages and can be used as an antagonist to the endotoxic shock caused by Salmonella lipopolysaccharide. J Biochem (Tokyo), 1988 Mar, 103(3), 499 - 503 Catalytic properties of cytochrome c oxidase purified from Nitrosomonas europaea; Yamazaki T et al.; Cytochrome c oxidase of Nitrosomonas europaea reacts with not only the native cytochrome c (N . europaea cytochrome c-552) but also horse and yeast cytochromes c . The effects on its reactivity of various reagents were very different between the reactions with the native and eukaryotic cytochromes c as the electron donors . The oxidation of eukaryotic ferrocytochrome c by the oxidase was activated by addition of anionic detergents such as sodium dodecyl sulfate and sodium cholate, and anionic phospholipids such as cardiolipin, phosphatidylserine, phosphatidylinositol, and phosphatidylethanolamine, while the reaction was not activated by Triton X-100, Tween 20, or phosphatidylcholine . However, the reaction with the native cytochrome c of the enzyme was hardly affected by any of the detergents and phospholipids mentioned above, while it was activated by the presence of poly-L-lysine. Appl Environ Microbiol, 1988 Jan, 54(1), 172 - 5 Aquatic nitrogen transformations at low oxygen concentrations; Downes MT; Nitrite and nitrous oxide made up 40% of the hypolimnetic dissolved inorganic nitrogen in mesotrophic Lake Rotoiti, New Zealand, prior to hypolimnetic anoxia . Up to 120 mg of N m-3 as nitrite and 20 mg of N m-3 as nitrous oxide accumulated, whereas dissolved-oxygen concentrations remained between 1.0 and 0.2 g m-3 and were totally consumed when the hypolimnion became completely anoxic . Assays of water column nitrification potentials, together with measurements of the relative rates of nitrate and nitrite reduction, suggested that at low dissolved-oxygen concentrations both nitrite and nitrous oxide were produced mainly by ammonium-oxidizing bacteria, with nitrous oxide being a product of nitrifier denitrification. Arch Microbiol, 1988, 149(6), 547 - 56 A phylogenetic survey of budding, and/or prosthecate, non-phototrophic eubacteria: membership of Hyphomicrobium, Hyphomonas, Pedomicrobium, Filomicrobium, Caulobacter and "dichotomicrobium" to the alpha-subdivision of purple non-sulfur bacteria; Stackebrandt E et al.; The phylogenetic position of various budding and/or or prosthecate Gram-negative eubacteria was determined by different methods . Members of the genera Hyphomicrobium, Filomicrobium, Pedomicrobium were investigated by 16S rRNA cataloguing, a 1373 nucleotide long portion of the 16S rRNA was sequenced from Hyphomicrobium vulgare and the 5S rRNAs were analyzed from two Hyphomicrobium strains, Hyphomonas polymorpha and Caulobacter crescentus . Comparison with published sequences indicated a membership of all of these organisms to the alpha subdivision of purple bacteria . While C . crescentus and Hyphomonas polymorpha constitute separate individual lines of descent, the position of a coherent cluster embracing Hyphomicrobium, Pedomicrobium and Filomicrobium is not yet settled . 16S rRNA cataloguing indicate the presence of a distinct line equivalent to other subgroups in its phylogenetic depth . 5S rRNA analysis, on the other hand, groups Hyphomicrobium vulgare and strain IFAM 1761 with members of subgroup alpha-2 (Rhodopseudomonas palustris, Nitrobacter winogradskyi and relatives) . In contrast to the present classification, Pedomicrobium ferrugineum and Filimicrobium fusiforme are more closely related to certain Hyphomicrobium strains than these are related among each other . Budding mode of reproduction and prosthecate morphology are dominating morphological features of members of the alpha subdivision . These characteristics may gain diagnostic significance in a future formal description of this subdivision and its subgroups as a higher rank. J Biochem (Tokyo), 1987 Sep, 102(3), 525 - 30 Nitrobacter winogradskyi cytochrome a1c1 is an iron-sulfur molybdoenzyme having hemes a and c; Fukuoka M et al.; Cytochrome a1c1 (nitrite-cytochrome c oxidoreductase) purified from Nitrobacter winogradskyi (formerly N . agilis) contained molybdenum, non-heme iron, and acid-labile sulfur in addition to hemes a and c; it contained 1 mol of heme a, 4-5 g atoms of non-heme iron, 2-5 g atoms of acid-labile sulfur, and 1-2 g atoms of molybdenum per mol of heme c, but did not contain copper . The fluorescence spectra of the molybdenum cofactor derivative prepared from cytochrome a1c1 were very similar to those of the cofactor derivative from xanthine oxidase, and the aponitrate reductase of nit-1 mutant of Neurospora crassa was complemented by addition of the molybdenum cofactor derived from the cytochrome . Further, the ESR spectrum of cytochrome a1c1 was similar to that of liver sulfite oxidase . The content of cytochrome a1 in the cells cultivated with the medium in which tungsten was substituted for molybdenum markedly decreased as compared with that in the cells cultivated in the molybdenum-supplemented medium . These results indicate that cytochrome a1c1 is an iron-sulfur molybdoenzyme which contains hemes a and c. Eur J Biochem, 1987 Jan 15, 162(2), 299 - 304 Conformational change accompanies redox reactions of the tetraheme cytochrome c-554 of Nitrosomonas europaea; DiSpirito AA et al.; Cytochrome c-554 of the ammonia-oxidizing chemolithoautotropic bacteria is thought to mediate electron transfer from hydroxylamine oxidoreductase to a terminal oxidase and/or to ammonia monooxygenase . The cytochrome has four c hemes which interact magnetically and have the same redox potential . We report that the kinetics of reduction of ferric cytochrome c-554 by dithionite or the oxidation of ferrous cytochrome c-554 by O2 or H2O2 are complex and multiphasic . Transient rapid-scan difference spectra indicate discrete maxima at approximately 418 nm, 425 nm and 432 nm . Absorbance changes at all three difference maxima appear to occur in all kinetic phases, although not in equal amounts for each wavelength . Reduction by 20 mM dithionite was biphasic . At pH 7.5 the first phase, which involved approximately 50% of the total absorbance change, had a rate constant (20 degrees C) of 140 s-1 and energy of activation of 20 kJ X mol-1 . The slow phase had a rate constant 0.43 s-1 and a relatively high energy of activation, 87 kJ X mol-1, suggesting that a change in protein configuration accompanied the reaction . As the pH of the solution increased, the rate constant for both phases decreased and the fraction of absorbance change in the rapid phase increased . Oxidation of ferrous cytochrome c-554 by O2 involved a discrete rapid phase with a rate constant of 14 s-1, accounting for 6% of the absorbance . The remainder of the reaction was multiphasic with rate constants in the range 0.1-0.01 s-1 . With H2O2 as the oxidant, the rapid phase involved 39% of the change in absorbance with a rate constant of 19 s-1 . The remainder of the reoxidation was multiphasic with rate constants ranging over 0.4-0.01 s-1. J Biol Chem, 1986 Dec 25, 261(36), 17048 - 56 Cytochrome aa3 from Nitrosomonas europaea; Dispirito AA et al.; Cytochrome c oxidase has been purified from the ammonia oxidizing chemoautotroph Nitrosomonas europaea by ion-exchange chromatography in the presence of Triton X-100 . The enzyme has absorption maxima at 420 and 592 nm in the resting state and at 444 and 598 nm in the dithionite-reduced form; optical extinction coefficient (598 nm minus 640 nm) = 21.9 cm-1 nM-1 . The enzyme has approximately 11 nmol of heme a and approximately 11 nmol of copper per mg of protein (Lowry procedure) . There appear to be three subunits (approximate molecular weights 50,800, 38,400, and 35,500), two heme groups (a and a3), and two copper atoms per minimal unit . The EPR spectra of the resting and partially reduced enzyme are remarkably similar to the corresponding spectra of the mitochondrial cytochrome aa3-type oxidase . Although the enzyme had been previously classified as "cytochrome a1" on the basis of its ferrous alpha absorption maximum (598 nm), its metal content and EPR spectral properties clearly show that it is better classified as a cytochrome aa3 . Neither the data reported here nor a review of the literature supports the existence of cytochrome a1 as an entity discrete from cytochrome aa3 . The purified enzyme is reduced rapidly by ferrous horse heart cytochrome c or cytochrome c-554 from N . europaea, but not with cytochrome c-552 from N . europaea . The identity of the natural electron donor is as yet unestablished . With horse heart cytochrome c as electron donor, the purified enzyme could account for a significant portion of the terminal oxidase activity in vivo. J Biochem (Tokyo), 1986 Dec, 100(6), 1465 - 70 Measurement of proton pump activity of the thermophilic bacterium PS3 and Nitrobacter agilis at the cytochrome oxidase level using total membrane and heptyl thioglucoside; Sone N; It is possible to prepare liposomal vesicles by solubilization of total bacterial membranes with n-heptyl beta-D-thioglucoside followed by reconstitution into proteoliposomes by a freeze-thaw-sonication procedure with soybean phospholipids . The resulting proteoliposomes from total membrane fraction of sufficiently aerated cells of the thermophilic bacterium PS3 containing cytochrome aa3 showed a reasonable H+ pumping activity upon addition of reduced cytochrome c . On the other hand, the proteoliposomes reconstituted from air-limited PS3 cells containing cytochrome o and those from Nitrobacter agilis cells containing cytochrome aa3 did not show H+ pumping upon addition of reduced cytochrome c, although the vesicles showed "respiratory control"; 3-4-fold stimulation of oxygen consumption took place upon addition of an uncoupler . In proteoliposomes prepared from PS3 membranes by this method, H+-translocating ATPase (F0 X F1) was successfully reconstituted as well, suggesting that this method has wide applicability for investigation of enzymes catalyzing transmembrane processes. Arch Biochem Biophys, 1986 Oct, 250(1), 228 - 32 Pathway of oxidation of pyruvic oxime by a heterotrophic nitrifier of the genus Alcaligenes: evidence against nitroethane as an intermediate; Castignetti D et al.; The role of nitroethane as an intermediate in the oxidation of pyruvic oxime to nitrate by an Alcaligenes sp . was examined . Unlike pyruvic oxime, which serves as a sole source of C and N for the bacterium, nitroethane was incapable of supporting the growth of the microbe . Nitroethane was metabolized and diauxic growth did occur, however, if the nitroethane medium was amended with yeast extract . Alcaligenes sp . resting cells and cell-free extracts were prepared from nitroethane-yeast extract grown cultures and the maximum rate of nitrite synthesis when nitroethane was the substrate was 6.8 nmol min-1 mg cell protein-1, a 10-fold lower rate than that previously noted for pyruvic oxime oxidation . These cell-free extracts were unable to metabolize pyruvic oxime . Resting cells and cell-free extracts prepared from Alcaligenes sp . cells grown in a pyruvic oxime medium were, conversely, incapable of metabolizing nitroethane . Collectively, these results indicate that nitroethane is not an intermediate in the pathway of pyruvic oxime oxidation and that two separate enzyme systems exist in the Alcaligenes sp . for the metabolism of pyruvic oxime and nitroethane. J Biol Chem, 1986 Aug 15, 261(23), 10538 - 43 Catalysis of intermolecular oxygen atom transfer by nitrite dehydrogenase of Nitrobacter agilis; Friedman SH et al.; Nitrobacter agilis, which contains a very active nitrite dehydrogenase, was studied in vivo under anaerobic conditions by the 15N NMR technique . When incubated with equimolar 15NO3- and unlabeled nitrite (or 15NO2- and unlabeled nitrate) the bacterium catalyzed an isotope exchange reaction at rates about 10% those observed in the nitrite oxidase assay . When incubated with 18O-labeled 15NO2- and 18O-labeled 15NO3-, the 18O was observed to exchange at similar rates from both species into water . Finally, when incubated with equimolar {18O}nitrate and 15NO2-, intermolecular 18O transfer was observed to result in formation of double labeled nitrate and nitrite at similar rates . 18O was transferred from nitrate to a 15N species or to water at approximately equal rates under the conditions of the experiments . It is argued that the enzyme responsible for these exchange reactions is nitrite dehydrogenase and not nitrate reductase . This work and the related experiments of DiSpirito and Hooper (DiSpirito, A.A., and Hooper, A.B . (1986) J . Biol . Chem . 261, 10534-10537) represent the first demonstrations of intermolecular oxygen atom transfer among oxotransferases . Mechanistic implications are discussed. J Biol Chem, 1986 Aug 15, 261(23), 10534 - 7 Oxygen exchange between nitrate molecules during nitrite oxidation by Nitrobacter; DiSpirito AA et al.; During oxidation of nitrite, cells of Nitrobacter winogradskyi are shown to catalyze the active exchange of oxygen atoms between exogenous nitrate molecules (production of 15N16/18O3- during incubation of 14N16/18O3-, 15N16O3-, and 15N16O2- in H216O) . Little, if any, exchange of oxygens between nitrate and water also occurs (production of 15N16/18O3- during incubation of 15N16O3- and 14N16O2- in H218O) . 15N species of nitrate were assayed by 18O-isotope shift in 15N NMR . Taking into account the O-exchange reactions which occur during nitrite oxidation, H2O is seen to be the source of O in nitrate produced by oxidation of nitrite by N . winogradskyi . The data do not establish whether the nitrate-nitrate O exchange is catalyzed by nitrite oxidase (H2O + HNO2----HNO3 + 2H+ + 2e-) or nitrate reductase (HNO3 + 2H+ + 2e-----HNO2 + H2O) or both enzymes in consort . The nitrate-nitrate exchange reaction suggests the existence of an oxygen derivative of a H2O-utilizing oxidoreductase. Mikrobiologiia, 1986 Mar-Apr, 55(2), 305 - 10 {Subordination of the taxa of gram-negative bacteria determined by numerical analysis methods}; Romanovskaia VA et al.; Various numerical methods were used to estimate the coordination of taxa of gram-negative aerobic and facultative anaerobic organoheterotrophic and chemolithotrophic bacteria . Stable phena were found to be formed by cultures belonging to the families Rhizobiaceae, Halobacteriaceae, Enterobacteriaceae, Nitrobacteriaceae (except the genus Nitrobacter), and Methylomonadaceae (except the genus Methylococcus) . The unstable position was found in the genera Thermus, Zoogloea, Xanthomonas, Sulfolobus, Methylococcus, Alcaligenes, Brucella, and Acetobacter . The greatest scatter among the objects being analysed was detected among genera belonging to the family Pseudomonadaceae . The taxonomic position of these genera must be defined more precisely . The family Methylomonadaceae is related to such physiologically unique groups of microorganisms as nitrifying, sulfate-reducing, extreme thermophilic and halophilic forms . All in all, the data reported in this work show that numerical analysis can be used to specify the classification structure of bacteria . In a number of cases, the results are consistent with those changes which are performed in the Bergey Manual 9 using logical analysis (for instance, concerning the position of the genera Gluconobacter, Acetobacter, Beijerinckia, and Derxia). J Biol Chem, 1986 Jan 25, 261(3), 1126 - 38 Tetraheme cytochrome c-554 from Nitrosomonas europaea . Heme-heme interactions and ligand binding; Andersson KK et al.; Cytochrome c-554 functions in the ammonia oxidizing system of Nitrosomonas europaea . We have investigated its molecular and ligand binding properties and studied the protein with optical, EPR, and Mossbauer spectroscopies in the pH range from 2 to 13 . Amino acid, heme, and metal analyses show that the protein has Mr = 25,000 and that it contains four c-type hemes per molecule . Optical spectra reveal that the heme ligand structures are sensitive to the pH of the medium and that the hemes can bind small molecules such as CN-, CO, and NO under certain conditions . According to the Mossbauer and EPR studies of the ferric protein, the hemes are predominantly (75%) high spin at pH 2 and low spin (approximately equal to 100%) above pH 10 . At neutral pH, Mossbauer data show that 75% of the heme is low spin and that the remainder is high spin . The EPR data, however, do not reveal any signals attributable to typical high spin or low spin species . Rather, a very complex and unusual spectrum with a main feature at g = 3.3 is observed at X-band, this feature shifts to approximately g = 3 at S-band . The EPR and Mossbauer data show clearly that the hemes are magnetically interacting, by dipolar and exchange interactions . At pH 2, the EPR spectra reveal resonances at g = 6 and 2 . The Mossbauer spectra prove that all hemes are magnetically coupled at this pH . Coupling is also borne out by the observation of a half-field EPR resonance near g = 12. Biochem Int, 1986 Jan, 12(1), 167 - 72 N-terminal amino acid sequence of cytochrome c-552 from Nitrosomonas europaea; Miller DJ et al.; Nitrosomonas europaea is an ammonia-oxidizing bacterium which contains multiple c-type cytochromes . Few of these components have been assigned physiological roles, but on the basis of molecular weight and redox potential cytochrome c-552 has been considered to be an analogue of the mitochondrial cytochrome-c family of proteins . We present the N-terminal amino acid sequence (47 residues) of cytochrome c-552 and show that this protein is most closely related to the group of small cytochrome-c components from pseudomonads (cytochromes c-551) and is probably evolutionarily distant from the analagous protein (cytochrome c-550) from the nitrite-oxidizing bacterium Nitrobacter agilis. Zentralbl Bakteriol Mikrobiol Hyg {B}, 1985 Jun, 181(1-2), 37 - 51 {Microflora in swine slurry as a parameter in determining the efficiency of deodorizing treatment . I . Continuous and discontinuous aeration treatment}; Hennlich W; Liquid manure from the pig, fresh and stored, was treated by continuous and discontinuous aeration . The purpose was to achieve a biologically stabilized and deodorized organic material . The samples which were aerated intermittently had good decomposition rates for nitrogen compounds and even so good deodorization effects . In spite of a minimum of dissolved oxygen of appr . 0.2 mg/l, good deodorization could be achieved by intermittent aeration for 23 days . Simultaneous processes of nitrification and denitrification were observed in optimal aerated manure similar to activated sludge processes . On the other hand, significant shifts on the microflora could be shown, whereby the main part of the biota consists in the gramnegative, non fermentative organisms . In non-deodorized liquid manure, members of the genus Bacillus advanced in their growth rates . In addition to Alcaligenes-Pseudomonas organisms, the group of nonfermentative cocci (e . g . Moraxella spp., Paracoccus spp.) dominated . Their growth development during the treatment agreed very well with the results of decomposition and deodorization . The existence of Bifidobacterium and of Aerococcus in aerated pig slurry was not ascribed before. Biochem J, 1985 May 1, 227(3), 719 - 25 Suicidal inactivation and labelling of ammonia mono-oxygenase by acetylene; Hyman MR et al.; Acetylene brings about a progressive inactivation of ammonia mono-oxygenase, the ammonia-oxidizing enzyme in Nitrosomonas europaea . High NH4+ ion concentrations were protective . The inactivation followed first-order kinetics, with a rate constant of 1.5 min-1 at saturating concentrations of acetylene . If acetylene was added in the absence of O2, the cells remained active until O2 was re-introduced . A protective effect was also demonstrated with thiourea, a reversible non-competitive inhibitor of ammonia oxidation . Incubation of cells with {14C}acetylene was found to cause labelling of a single membrane polypeptide . This ran on dodecyl sulphate/polyacrylamide-gel electrophoresis with an Mr value of 28 000 . It is concluded that acetylene is a suicide substrate for the mono-oxygenase . The labelling experiment provides the first identification of a constituent polypeptide of ammonia mono-oxygenase. Arch Microbiol, 1985 Apr, 141(3), 214 - 8 Deoxyribonucleic acid homologies among 96 strains of ammonia-oxidizing bacteria; Koops HP et al.; DNA of 96 strains of the genera Nitrosomonas, Nitrosococcus, Nitrosospira, Nitrosolobus, and Nitrosovibrio was isolated and analysed spectrophotometrically . Percentages of guanine plus cytosine (G + C) content, genome sizes, and DNA-DNA homologies were determined . The results indicated the presence of eight Nitrosomonas species, three or four Nitrosococcus species, five Nitrosospira species, and two species of both Nitrosolobus and Nitrosovibrio . DNA homologies between strains of a separate species ranged from 56-100% . Average homologies between strains of different species were 33% in Nitrosococcus, 36% in Nitrosomonas, 37% in Nitrosolobus, 40% in Nitrosospira, and 42% in Nitrosovibrio . Average homologies between species of different genera were 33% and thus not significantly above the background value of 30% detected between DNA of ammonia-oxidizing bacteria and Escherichia coli . Genome sizes ranged from 1.90 - 2.74 X 10(9) dalton in Nitrosomonas, 2.09 - 2.37 X 10(9) dalton in Nitrosococcus, 1.87 - 2.15 X 10(9) dalton in Nitrosospira, 1.92 - 2.10 X 10(9) dalton in Nitrosolobus, and 1.91 - 2.15 X 10(9) dalton in Nitrosovibrio . Differences in genome sizes were in accordance with DNA homologies. Carcinogenesis, 1985 Apr, 6(4), 641 - 3 Similar carcinogenic effects in rats of 1-ethyl-1-nitroso-3-hydroxyethylurea and 1-hydroxyethyl-1-nitroso-3-ethylurea; Lijinsky W et al.; The two isomeric N-nitroso derivatives of the dialkylurea, 1-ethyl-3-(2-hydroxyethyl)urea, were given by gavage to 20 male F344 rats for 30 weeks at equimolar doses . The tumorigenic responses were compared with those to a similar dose of nitrosoethylurea or nitroso-2-hydroxyethylurea . Each of the nitrosomonoalkylureas caused death from tumors more rapidly than the analogous nitrosodialkylurea . Each of the nitrosodialkylureas induced a broader spectrum of tumors in the rats than did either nitrosoethylurea or nitroso-2-hydroxyethylurea, including neoplasms of the thyroid, lung, skin, colon, mesotheliomas and neoplasms of the brain and liver in high incidence, the last two of which were not seen in animals given the nitrosomonoalkylureas . On the other hand, there were fewer tumors of the forestomach in rats given the nitrosodialkylureas than with the nitrosomonoalkylureas . The major difference between 1-nitroso-1-ethyl-3-hydroxyethylurea and 1-nitroso-1-hydroxyethyl-3-ethylurea was that the former induced only neoplastic nodules in the liver of 30% of the rats, while the latter induced hepatocellular carcinomas in 55% of the rats; approximately half of the rats given either compound had brain neoplasms, which included astrocytomas, gliomas and oligodendrogliomas. Biochem J, 1985 Mar 1, 226(2), 499 - 507 Spectroscopic evidence for a photosensitive oxygenated state of ammonia mono-oxygenase; Shears JH et al.; Photoinactivation of ammonia oxidation by Nitrosomonas europaea cells by near-u.v . light was confirmed and further shown to occur with the same rate constant as loss of bromoethane-oxidation activity . Hydroxylamine oxidation was much less photosensitive . Protection against inactivation was afforded by anaerobiosis, organic substrates of ammonia mono-oxygenase such as bromoethane, or metal-ion-chelating agents such as thiourea . The presence of 10 mM-NH4+ or 1 mM-hydroxylamine made little difference, whereas hydrazine had a potentiating effect . Illumination of cells also caused a bleaching in the absorption spectrum around 380 nm, along with changes in the cytochrome gamma-band region . Similar effects below 400 nm were obtained when organic substrates and inhibitors of the mono-oxygenase were added to cells in the dark . The copper proteins haemocyanin and tyrosinase have a photosensitive oxygenated state with a near-u.v . absorption band of similar half-width . They also have a sensitivity to chelating agents similar to that of ammonia mono-oxygenase . The experimental results are explained in terms of a three-stage catalytic cycle analogous to that for tyrosinase . In resting cells most of the enzyme is believed to be in an oxygenated (Oxy) form, which absorbs maximally at 378 nm and is photosensitive . In the presence of a substrate, one O atom is inserted into the substrate and the other is reduced to water, leaving the enzyme in an oxidized (Met) state . This is followed by a two-electron reduction of the proposed binuclear copper site to give a reduced (Deoxy) state, which can bind O2 to complete the cycle. J Inorg Biochem, 1985 Mar-Apr, 23(3-4), 273 - 7 A comparative survey of several bacterial aa3-type cytochrome c oxidases; Yamanaka T et al.; The aa3-type cytochrome c oxidases purified from Nitrobacter agilis, Thiobacillus novellus, Nitrosomonas europaea, and Pseudomonas AM 1 were compared . They have haem a and copper atom as the prosthertic groups and show alpha and gamma absorption peaks at around 600 and 440 nm, respectively . Each oxidase molecule is composed of two kinds of subunits . The N . agilis oxidase has 2 moles of haem a and 2 atoms of copper in the minimal structural unit composed of one molecule each of the two kinds of subunits, while the T . novellus enzyme seems to contain one molecule of the haem and one atom of the metal in the unit . The N . europaea oxidase shows very low affinity for carbon monoxide . Each oxidase reacts rapidly with some eukaryotic cytochromes c as well as with its native cytochrome c . The cytochrome c oxidase activity of the N . agilis oxidase is 50% inhibited by 1 microM KCN, while 50% inhibition of the activity requires 100 microM KCN in the case of the N . europaea enzyme. Can J Microbiol, 1985 Feb, 31(2), 139 - 44 Nitrite and nitrous oxide production by Methylosinus trichosporium; Yoshinari T; Conditions for the production of nitrite and nitrous oxide by an obligate methanotroph, Methylosinus trichosporium (OB 3b), were studied . The rate of nitrite production (V NO2-) was correlated with the concentration of ammonia up to 20 mM in the presence of sufficient amounts of oxygen and inversely correlated with the amounts of methane in the system . The rate of nitrous oxide (N2O) production (V N2O) was correlated positively with V NO2- and the amount of nitrite produced and inversely with the oxygen concentration in the system . Nitrite started to disappear when either oxygen or methane or both were depleted, but only a part of the loss could be accounted for by an increase in N2O . Maximum rates of nitrite and N2O production by Ms . trichosporium were 6.9 X 10(-16) and 2.2 X 10(-17) mol . cell-1 X day-1, respectively . These values are about 0.2 and 1.6% of the values for Nitrosomonas europaea . Therefore, production of nitrite and N2O by methanotrophs in aquatic environments may not be as significant as that of Nitrosomonas. Zentralbl Mikrobiol, 1985, 140(7), 547 - 54 Influence of the herbicides Goltix and Sencor on nitrification process in two soils; Gadkari D; The effects of two herbicides, Sencor and Goltix, on nitrification in two soils were studied using a mixed culture of nitrifying bacteria . Sencor (10 ppm, 50 ppm, and 100 ppm) has no inhibitory influence on nitrification . In the presence of 50 ppm and 100 ppm Goltix the nitrification process is not affected but in the presence of 500 ppm Goltix ammonium oxidation is considerably retarded . In sandy loam field soil (pH 7.1) the retarding effect was more pronounced than in silty loamy sand (pH 7.8) of meadow . 500 ppm Goltix has a more lasting inhibitory effect on ammonium oxidation than some commercially available nitrification inhibitors. Arch Biochem Biophys, 1984 Sep, 233(2), 721 - 7 Source of the oxygen atoms of nitrate in the oxidation of nitrite by Nitrobacter agilis and evidence against a P-O-N anhydride mechanism in oxidative phosphorylation; Hollocher TC; 15N, 18O Tracer studies were applied to the aerobic oxidation of nitrite to nitrate by the chemolithotrophic bacterium, Nitrobacter agilis . It was established that, in conversion of nitrite to nitrate, one oxygen atom of nitrate arose from water and none from O2 or inorganic phosphate . This result confirms that of Kumar et al . {(1983) FEBS Lett . 152, 71-74} . Oxygen exchange between water and inorganic phosphate was small and that between water and nitrite or nitrate or any reaction intermediates between these two was not detected . Oxidation of nitrite was, therefore, effectively irreversible under the conditions employed . The uptake of extracellular phosphate was sufficient to allow significant transfer of 18O from phosphate to nitrate if oxidative phosphorylation had occurred by way of a P-O-N anhydride between phosphate (or ADP) and nitrate . The results are, therefore, inconsistent with the occurrence of a reaction of this type during nitrite oxidation. Can J Physiol Pharmacol, 1984 Aug, 62(8), 991 - 7 Acid rain and soil; vanLoon GW; A summary of important chemical properties of soil is given and the way in which acid rain may affect these properties is discussed . Acid rain may suppress microbiological decomposition and nitrification processes, thus influencing the nutrient status of soils . It has also been found that soil organic matter is less soluble in more acid solutions . Changed nutrient availability patterns are predicted in a low pH environment and enhanced leaching of essential elements from the soil exchange complex has been observed . Increased solubility of potentially toxic elements such as aluminium may also occur from soils which have been exposed to acidified rainfall. Anal Biochem, 1984 Aug 1, 140(2), 577 - 80 3,3',5,5'-tetramethylbenzidine/H2O2 staining is not specific for heme proteins separated by gel electrophoresis; Miller DJ et al.; 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 artifactual staining due to proteins of this type is possible. Rev Infect Dis, 1984 Jul-Aug, 6(4), 542 - 5 Unusual lipid A types in phototrophic bacteria and related species; Mayer H et al.; Photosynthetic bacteria of the Rhodospirillaceae family (sulfur-free purple bacteria) possess lipopolysaccharides (LPS) that deviate markedly from the Salmonella lipopolysaccharides in the chemical makeup of the lipid A component and in their biologic properties . LPS of Rhodopseudomonas gelatinosa is highly toxic and pyrogenic, while that of Rhodospirillum tenue shows cryptic toxicity . Two LPS types are completely non-toxic . The Rhodopseudomonas sphaeroides lipid A has the same backbone as that of Salmonella, but a part of the amide-linked fatty acids has the unusual 3-oxo structure (3-oxo-14:0) . The lipid A's of Rhodopseudomonas viridis and Rhodopseudomonas palustris have 2,3-diamino-2,3-dideoxy-D-glucose as the backbone sugar . This is the first demonstration of this sugar in nature . In recent studies using 16S rRNA sequencing, the nonphotosynthetic Nitrobacter strains were shown to be phylogenetically closely related to R . palustris . The R . palustris lipid A type has been identified in three Nitrobacter species, including Nitrobacter winogradskyi, the type strain . The data demonstrate the taxonomic significance of lipid A constituents and structures. Biochim Biophys Acta, 1984 Jun 26, 765(3), 268 - 74 Na+ and K+ transport in Nitrosomonas europaea and Nitrobacter agilis; Kumar S et al.; 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 constant, indicating that K+ transport was electrogenic in both bacteria . Using 22Na+-loaded cells, it is shown that both bacteria lack a respiration-dependent Na+ pump; however, antiporters for Na+/H+, K+/Na+ and K+/H+ were detected . Of these, at least the K+/Na+ antiporter required an electrochemical gradient for its operation . It is also shown that the unprotonated form of NH+4 is transported into these bacteria by a simple diffusion mechanism. Eur J Biochem, 1984 Jun 15, 141(3), 565 - 71 Kinetics of reduction by substrate or dithionite and heme-heme electron transfer in the multiheme hydroxylamine oxidoreductase; Hooper AB et al.; 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 with NH2OH (2.2 hemes c557 and 2 hemes c559 are reduced) or NH2NH2 (3.3 heme c 553 and 2 heme c559 are reduced) and (b) an H2O2-insensitive site(s) which is reactive with H2O2 (approximately 0.15 heme c553 is reduced); hydroquinone, pyrogallol, N-methyl hydroxylamine, pyocyanine, and ascorbate (approximately 0.8 heme c553 is reduced); or Na2S2O4 or EDTA-photoreduction with proflavin, deazalumiflavin or acridine orange and methylviologen (all hemes are reduced) . The rate constants at 19 degrees C for reduction by dithionite were: 0.7 heme c553 (7s-1), 4.3 hemes c553 (0.07 s-1), 0.7 heme c559 (0.8s-1), 1.3 hemes c559 (0.1s-1), P460 (0.013s-1) . At 2 degrees C the rate constant for 0.8 heme c559 was 1.7s-1 . The data indicate that one heme c552 is reduced by dithionite at the same rate as mammalian cytochrome c; other hemes are reduced much more slowly and are possibly inaccessible to the solvent . The rate constants at 2 degrees C for reduction by NH2OH were: 1.8 hemes c553 (30s-1), 0.2 heme c553 (2.4s-1), 1.7 hemes c559 (19s-1), 0.3 heme c559 (1.4s-1) . For reduction by NH2NH2 the values were: 2.6 hemes c553 (23s-1), 0.7 heme c553 (1.6s-1), 1.3 hemes c559 (22s-1), 0.7 heme c559 (4.2s-1) . Thus reduction by NH2OH at the substrate site was at least an order of magnitude faster than reduction of hydroxylamine oxidoreductase heme by Na2S2O4 . Comparison of rates of heme-heme electron transfer on the enzyme during reoxidation by O2 or H2O2, reduction by Na2S2O4 and reduction by NH2OH or NH2NH2 indicates that the enzyme can exist in distinct states which result in different rates of heme-heme electron transfer . Comparison of the rate of substrate reduction of c hemes of hydroxylamine oxidoreductase (HAO) with the turnover of the enzyme in vivo is consistent with the electron path NH2OH----HAO P460----HAO c hemes----biological electron acceptor. J Biol Chem, 1984 Jun 10, 259(11), 6833 - 40 Mössbauer, EPR, and optical studies of the P-460 center of hydroxylamine oxidoreductase from Nitrosomonas . A ferrous heme with an unusually large quadrupole splitting; Andersson KK et al.; 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) . Mossbauer spectra of the reduced P-460 groups, in hydroxylamine oxidoreductase and the fragment, exhibit nearly identical quadrupole doublets with an unusually large splitting, delta EQ = 4.21 mm/s (no ferrous heme protein is known with delta EQ greater than 2.75 mm/s) . The observed isomer shift, delta = 0.96 mm/s at 4.2 K, shows that the P-460 iron is high spin ferrous . Treatment of oxidized hydroxylamine oxidoreductase with H2O2 followed by reduction or exposure of the native sample to CO led to the disappearance of both the characteristic 460 nm absorption band (epsilon = 89 mM-1 cm-1) and the delta EQ = 4.21 mm/s doublet . The iron of the oxidized P-460 fragment is high spin ferric, with Mossbauer and EPR parameters very similar to those of metmyoglobin . Optical spectra of the reduced P-460 fragment show long wavelength bands at 650 and 688 nm which are sensitive to treatment of the fragment with reagents which react with P-460 . These bands were, however, not detected in hydroxylamine oxidoreductase . The spectroscopic and chemical evidence obtained to date suggests strongly that the P-460 iron resides in a heme-like macrocycle although the presumed porphyrin must have some unusual features. FEBS Lett, 1984 May 21, 170(2), 331 - 4 Diheme cytochrome c-554 from Nitrosomonas . Soret resonance Raman indication of an unusual ferric 5-coordinate structure; Andersson KK et al.; 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 (HRP) or cytochrome c peroxidase (CcP) at pH 6.4 . The narrow linewidth of the heme core-size vibrations indicates that both heme irons of c-554 have similar geometries. Natl Cancer Inst Monogr, 1984 May, 65, 187 - 93 Physiological responses of experimental fish to stressful conditions; Gratzek JB et al.; Common stress factors in the laboratory aquarium can include extremes of pH, temperature, or other factors, such as the accumulation of intermediates of nitrification . Each aberration from optimal conditions has a direct physiological effect on fish that can cause death in a variety of ways . The stress effect in fish leading to infectious diseases is a common physiological manifestation of some common biochemical change, probably hormonal, which may compromise the immune system and lead to a decreased disease resistance and ultimately death . Minimization of stress by careful attention to basic fish culture practices is perhaps the best way one can ensure successful laboratory experiments. Appl Environ Microbiol, 1984 Feb, 47(2), 424 - 6 Use of nitrifying activity measurements for describing the effect of salinity on nitrification in the Scheldt estuary; Somville M; Nitrifying activity measurements, carried out on freshly collected samples from an estuarine environment, show that the composition of the nitrifier population undergoes a progressive modification during the mixing of freshwater masses in seawater, with increasing tolerance to salt . As a result, the overall effect of increasing salinity on nitrification is much less severe than the direct effect of salt on the freshwater nitrifying population. Rev Argent Microbiol, 1984, 16(3), 153 - 8 {Nitrification in soil columns subjected to continuous flow}; Marengo GW; Nitrification in columns of soil under continuous flow of substrate was studied . The soil was previously diluted with sterile sand (1 part of soil: 9 parts of sand; w : w) and admixed with 2% CaCO3 . Soil columns, 15 cm high, were contained in glass cylinders with a cross sectional area of 39.6 cm2 . In the main experiment, a soil column was subjected to the continuous flow of a KNO2 solution (100 ppm NO2- - N) at a flow rate of 46.0 cm3 h-1 . An exponential increase of nitrate concentration in the column effluent was observed during the first 4 days (Fig . 1), suggesting an exponential growth of NO2- oxidizers in the soil column, with an apparent generation time of 1, 2 days . At the end of this phase, an almost complete conversion of nitrite to nitrate was reached followed by an important decrease in conversion and by a partial recovery with stabilization at 69 ppm NO3- - N in the column effluent . This phenomenon was presumably due to a rapid rate of O2 demand by the microorganisms which exceeded the supply, and to the subsequent adaptation of the NO2- oxidizers to a situation in which the O2 concentration was the limiting factor . At the end of the experiment, the average population density of NO2- oxidizers in the column was 1.5 . 10(7) cells cm-3 . In a preliminary experiment, a column of the same soil was continuously perfused with an (NH4)2SO4 solution with 140 ppm NH+4 - N, at a constant rate of 40.8 cm3 h-1 (Fig . 2.).(ABSTRACT TRUNCATED AT 250 WORDS) Orig Life, 1984, 14(1-4), 739 - 46 A relationship between prokaryote and eukaryote observed in Nitrobacter agilis cytochromes AA3 and C; Yamanaka T et al.; Cytochrome aa3 (cytochrome c oxidase) and cytochrome c were purified from Nitrobacter agilis, and some of their properties were compared with those of the respective counterparts of eukaryote from the evolutionary point of view . N . agilis cytochrome aa3 has many functional and structural properties similar to those of eukaryotic cytochrome aa3, although its molecule is composed of only two kinds of subunits unlike the eukaryotic cytochrome which is composed of 7 kinds of subunits . N . agilis cytochrome c is homologous to eukaryotic cytochrome c; 50 amino acid residues of the bacterial cytochrome c are identical with those of horse cytochrome c . It reacts with yeast cytochrome c peroxidase as rapidly as eukaryotic cytochrome c does . So far as based on the molecular features of cytochromes aa3 and c, N . agilis appears to be one of the organisms which may link in evolution prokaryote to eukaryote. Zentralbl Bakteriol Mikrobiol Hyg {B}, 1983 Sep, 178(1-2), 81 - 97 {Current technology of waste water treatment}; Bischofsberger W et al.; For the purification of municipal waste water and industrial waste water predominantly burdened by organic matter, mechanical-biological plants partly based on the method of activation and partly on the trickling filter system are preferably used . Recently overloading of existing plants and tighter water protection requirements imposed the necessity of boosting the performance of conventional biological processes by reducing the sludge burden and the loading per unit volume . This has also resulted in nitrification of the nitrogen compounds and in extensive sludge stabilization . As the oxygen supply to the micro-organisms requires the highest expenditure of energy in the activation process, special attention was given to the development of efficient aeration systems . For waste water containing a high proportion of substances which prove difficult to decompose, or waste water subject to strong fluctuations, multi-stage biological procedures or a combination of various processes are used increasingly . In this context, chemical precipitation for the elimination of phosphorus and biological nitrogen elimination have proven themselves as additional purification methods. Eur J Biochem, 1983 Jul 15, 134(1), 83 - 7 Heme P460 of hydroxylamine oxidoreductase of Nitrosomonas . Reaction with CO and H2O2; Hooper AB et al.; 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 ferrous c hemes following specific destruction of heme P460 . Reaction of ferrous P460 with H2O2 is rate-limiting . Activation of dioxygen for N-oxidation by ferrous HAO may involve the two-electron reduction of O2 by P460 . The reaction of ferrous HAO with H2O2 was studied as it may reveal aspects of the mechanism of activation of dioxygen . Reaction of ferrous heme P460 with CO is slow and with low affinity as compared with other hemoproteins . Values for reaction of CO with enzyme were: k1, 1.1 X 10(-3) M-1 s-1 and Kd, 12 microM. Arch Biochem Biophys, 1983 Jul 15, 224(2), 587 - 93 Pathway of oxidation of pyruvic oxime by a heterotrophic nitrifier of the genus Alcaligenes: evidence against hydrolysis to pyruvate and hydroxylamine; Castignetti D et al.; A heterotrophic nitrifier of the genus Alcaligenes, which grows vigorously on pyruvic oxime, was tested by several methods for possible differences or similarities in metabolic performance between pyruvic oxime and its hydrolysis products, pyruvate and hydroxylamine . Major differences were observed between pyruvic oxime and one or both of the other reductants with regard to growth yield, rates of reductant uptake, rates of oxygen uptake, sensitivity of their oxidations to inhibition by thiocyanate, and performance in reductant pulse experiments . Other oximes, some of which are structural analogs of pyruvic oxime and all of which are potential sources of hydroxylamine, were not metabolized by cells or cell-free extract . Collectively the results indicate a pathway of oxidation of pyruvic oxime to nitrite and CO2 that does not involve its initial hydrolysis, but probably involves the oxidation of N and/or C before C-N bond breakage. Ann Microbiol (Paris), 1983 Jul-Aug, 134B(1), 9 - 20 Taxonomy of phototrophic green and purple bacteria: a review; Pfennig N et al.; The presently existing classification for the green and purple bacteria comprises physiological-ecological assemblages of phototrophic bacteria with anoxygenic photosynthesis . The taxonomic units of the different levels were based entirely on common phenotypic traits, including morphological, cytological, physiological and biochemical characteristics . Since degrees of resemblance form the basis of the grouping, this classification cannot reflect the genetic or evolutionary relatedness of these bacteria, neither among themselves nor with other bacteria . The advantage of the artificial system, however, is the use of features which can be established in most laboratories and which allow the comparison and identification of newly isolated strains with those already studied and described . The four existing families correspond to the four major recognized, ecophysiological groups, the Chlorobiaceae and Chloroflexaceae among the green bacteria, and the Chromatiaceae and Rhodospirillaceae among the purple bacteria . Our knowledge of all these groups is incomplete; this is reflected by the fact that seven new species have been described during the past three years (6th Newsletter on phot . bacteria, Truper and Hansen, 1982) . The description of the new genus and species Erythrobacter longus (Shiba and Simidu, 1982) is also interesting, as it comprises aerobic chemoorganotrophic marine bacteria which form bacteriochlorophyll a and carotenoids; however, no strains were able to grow phototrophilcally . Significant success is currently being obtained in the different approaches toward elucidating the genetic relationships within and outside of the purple and green bacteria . Detailed studies of the lipopolysaccharides of several species and genera of the Rhodospirillaceae (Weckesser et al., 1979, and more recent paper) have proven to be very useful for the recognition of relationships or dissimilarities between the species of a genus or between different genera . Amino acid sequence studies of cytochromes c from Rhodospirillaceae, other bacteria and eukaryotic organisms (Dickerson, 1980) have led to the recognition of four different groups of cytochrome c molecules (long, medium and two groups of short protein chains) . The subdivision of the Rhodospirillaceae into three species groups, each possessing one of the three types of cytochrome c, proved to be in total agreement with the results of oligonucleotide cataloging of the 16 S ribosomal RNA of these bacteria (Gibson et al., 1979) . The latter method also revealed that several chemotropic bacteria, including the nitrifying bacteria, are more closely related to certain purple bacteria than different species of the purple bacteria among themselves (Seewaldt et al., 1982).(ABSTRACT TRUNCATED AT 400 WORDS) Biochem J, 1983 May 1, 211(2), 503 - 6 CO-binding c-type cytochromes and a high-potential cytochrome c in Nitrosomonas europaea; Miller DJ et al.; 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 were not resolved by gel-filtration chromatography or electrophoresis under denaturing conditions. Biochem J, 1983 Apr 15, 212(1), 31 - 7 Methane oxidation by Nitrosomonas europaea; Hyman MR et al.; 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 incubated with NH4+ under an atmosphere of 50% methane, 50 microM-methanol was generated in 1 h . It is concluded that methane is an alternative substrate for the NH3-oxidizing enzyme (ammonia mono-oxygenase),m albeit with a much lower affinity than for methane mono-oxygenase of methanotrophs. Antonie Van Leeuwenhoek, 1983 Apr, 49(1), 61 - 8 Proton translocation during denitrification by a nitrifying--denitrifying Alcaligenes sp; Castignetti D et al.; A heterotrophic nitrifying Alcaligenes sp . from soil was grown as a denitrifier on nitrate and subjected to oxidant pulse experiments to ascertain the apparent efficiencies of proton translocations during O2 and nitrogen-oxide respirations . With endogenous substrate as the reducing agent the leads to H+/2e- ratios, extrapolated to zero amount of oxidant per pulse, were 9.4, 3.7, 4.3 and 3.5 for O2, nitrate, nitrite and N2O, respectively . The value for O2 and those for the N-oxides are, respectively, somewhat larger and smaller than corresponding values for Paracoccus denitrificans . None of the three permeant ions employed with the Alcaligenes sp . (valinomycin-K+, thiocyanate and triphenylmethylphosphonium) was ideal for all purposes . Thiocyanate provided highest ratios for O2 but abolished the oxidant pulse response for nitrate and N2O . Valinomycin was slow to penetrate to the cytoplasmic membrane and relatively high concentrations were required for optimal performance . Triphenylmethylphosphonium enhanced passive proton permeability and diminished proton translocation at concentrations required to realize the maximal oxidant pulse response. Pediatrie, 1983 Mar, 38(2), 87 - 99 {Methemoglobinemia in acute diarrhea in infants}; Blanc JP et al.; 8 cases of methemoglobinemia are observed in infants of 28 days to 138 days of age, who have all acute diarrhea . They are divided in two groups . --4 infants who have eaten for a long time a rich nitrate and nitrite content carrot soup . --4 cases of severe diarrhea with probable endogenous nitrification due to microbial proliferation . The methemoglobinemia level is here not very high and represents more a witness that an alarming symptom . Those infants are compared with 10 infants who have diarrhea without methemoglobinemia . Symptoms and treatment of methemoglobinemia are revisited. Biosystems, 1983, 16(1), 1 - 8 Nitrogen fixation as evidence for the reducing nature of the early biosphere; Broda E et al.; Probably the first nitrogen fixers were anaerobic, non-photosynthetic, bacteria, i.e . fermenters . During the evolution of N2 fixation they still needed nitrogen on the oxidation level of ammonia . Because of the complexities in structure and function of nitrogenase this evolution must have required a long time . The photosynthetic and later the respiring bacteria inherited the capacity for N2 fixation from the fermenters, but the process did not change a great deal when it was taken over . Because of the long need for NH3, which is unstable in a redoxneutral atmosphere, a long-persisting reducing atmosphere was needed . The transition to a redoxneutral atmosphere, dominated by CO2, H2O and N2, cannot have been rapid, and the NH3 in it was recycled . Probably the atmosphere contained for a long time, as was suggested by Urey but is often denied now, a great deal of methane as a reductant . The recycling occurred with participation of intermediates like cyanide, through energy input as UV radiation or as electric discharges . A stationary state was set up . The hypothesis is recalled that coloured, photosynthetic, NH3 bacteria, analogous to coloured sulphur bacteria, may have existed, or may still exist, in reducing conditions . A few remarks are made about the origin of nitrification in the later, oxidizing atmosphere. Acta Microbiol Pol, 1983, 32(4), 373 - 80 Effect of microbiological hydrolysis of urea on the nitrification process; Krogulska B et al.; The aim of this study was to determine the causes of previously observed inhibition of stage II of nitrification in nitrifying activated sludge treating industrial wastewaters containing ammonium, urea and nitrates . Experiments made with both industrial wastewaters and synthetic medium containing equivalent concentrations of nitrogen compounds demonstrated that the factor limiting the activity of nitrobacteria is microbiological hydrolysis of urea, the causative agent probably being free ammonia released in the course of this hydrolysis. Can J Biochem, 1982 Nov, 60(11), 1018 - 24 Cytochrome c554 as a possible electron donor in the hydroxylation of ammonia and carbon monoxide in Nitrosomonas europaea; Tsang DC et al.; 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 reducing power required for the hydroxylation of carbon monoxide . The stoichiometry of the reaction, Km values for substrates, and effects of pH and inhibitors were investigated . It is concluded that carbon monoxide, a competitive inhibitor for ammonia oxidation, is an alternate substrate for ammonia hydroxylase using the reduced cytochrome c554 as the reducing power. Biochim Biophys Acta, 1982 Sep 22, 707(1), 14 - 20 The complete amino acid sequence of Nitrobacter agilis cytochrome c-550; Tanaka Y et al.; The amino acid sequence of cytochrome c-550 from the chemoautotroph, Nitrobacter agilis, was completed by using solid-phase sequencing and conventional procedures . The cytochrome was composed of 109 amino acid residues and its molecular weight was calculated to be 12375 including haem c . The cytochrome was homologous to eukaryotic cytochromes c and some photosynthetic bacterial cytochromes c2 . In particular, its primary structure was very similar to that of Rhodopseudomonas viridis cytochrome c2 . Some of its properties were compared with those of other cytochromes c on the basis of the primary structure. Biochemistry, 1982 Aug 17, 21(17), 3973 - 6 Resolution of multiple heme centers of hydroxylamine oxidoreductase from Nitrosomonas . 2 . Mössbauer spectroscopy; Lipscomb JD et al.; 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 Mossbauer spectroscopy . In the fully reduced enzyme, approximately seven hemes per alpha beta subunit contributed to one spectrum characteristic of low-spin ferrous heme . The remainder of the iron (10-15% of the total) yielded an ill-defined absorption pattern . Carbon monoxide binds to the P-460 as shown by optical spectra . The Mossbauer spectra of reduced hydroxylamine oxidoreductase which had been exposed to CO showed a new spectral component, corresponding to one iron site, with parameters characteristic of a low-spin ferrous heme-carbonyl complex . It appears that this component is derived from the ill-defined spectrum observed in the reduced enzyme . This is the first direct evidence that the P-450 moiety amounts to at least one Fe per alpha beta subunit . Together the Mossbauer results and the optical spectra suggest that the P-460 moiety is a heme . The Mossbauer spectra of the oxidized (as isolated) enzyme suggest the presence of one or two low-spin ferric hemes which might be EPR undetectable because of either fast electronic spin relaxation or participation in a spin-coupled pair . The spectra gave no evidence for the presence of a ferrous site in oxidized HAO. Appl Environ Microbiol, 1982 Apr, 43(4), 949 - 52 Effects of polychlorinated biphenyls and environmental biotransformation products on aquatic nitrification; Sayler GS et al.; 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 p-chloromandelic acid had no effect on nitrification. J Bacteriol, 1982 Mar, 149(3), 1013 - 20 Respiration-dependent proton translocation in Nitrosomonas europaea and its apparent absence in Nitrobacter agilis during inorganic oxidations; Hollocher TC et al.; 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 observed leads to H+/O ratio for ammonium ion oxidation by Nitrosomonas europaea was 3.4; that for hydroxylamine and hydrazine cation oxidation was 4.4 . These values, when corrected for production of stoichiometric protons and for the fact that the first step in ammonium ion oxidation (hydroxylamine production) is mediated by a monooxygenase, give effective leads to H+/O ratios of about 4 for these three substrates . This value compares favorably with those obtained with other aerobes . No convincing evidence was obtained for operation of a respiratory proton pump in Nitrobacter agilis during nitrite oxidation . Implications of this unexpected result are discussed. Antonie Van Leeuwenhoek, 1982, 48(4), 327 - 36 Incorporation of organic compounds into cell protein by lithotrophic, ammonia-oxidizing bacteria; Martiny H et al.; 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 pyruvate preferably entered into the amino acids of the pyruvate and glutamate family and from acetate mainly into leucine and the glutamate family . Among the strains examined, slight differences were observed, but all should be included under group A of the scheme of Smith and Hoare (1977). J Environ Sci Health B, 1982, 17(4), 393 - 407 Bacterial metabolism under conditions representing pesticide disposal pits; Grant MA et al.; Bacterial cultures were incubated with pesticides at concentrations ranging from 1 to 5,000 ppm . The species selected are important in one or more of the following biogeochemical processes: nitrogen fixation, nitrification, denitrification, sulfur oxidation, sulfate reduction, carbon dioxide fixation, and respiratory carbon dioxide evolution . The pesticides used were atrazine, alachlor, carbaryl, parathion, trifluralin, and 2,4-D . Bacterial cultures were exposed to commercial formulations of these pesticides and to pesticide samples from active disposal pits. Arch Environ Contam Toxicol, 1982, 11(2), 185 - 93 Chlorflurenol-methyl in soil: degradation, leaching, and effects on microbiological processes; Eichler D et al.; Tests were conducted with the synthetic growth regulator chlorflurenol-methyl to investigate its rate of degradation in soil, leaching behavior, and possible side-effects on the soil microflora and on soil physiological processes . With two sandy soils (Ct = 1.0 and 2.58%) which were treated with 11.35 mg kg-1 chlorflurenol-methyl (congruent to 2.8 kg a.i . ha-1), over 90% of the compound disappeared within 4 to 8 days . The degradation products were 2-chloro-9-hydroxyfluorene-9-carboxylic acid and 2-chlorofluorenone, which undergo further decomposition . In leaching tests with three sandy soils (Ct = 0.69, 1.0 and 2.58%), chlorflurenol-methyl was not washed from the soil; however, with one soil (0.69% C), very small residues were observed in the effluent identified as 2-chlorofluorenone . In side-effects experiments with a parabrown (Ct = 1.26%) and a chernozem soil (Ct = 2.3%), which were treated with 1 and 10 mg kg-1 chlorflurenolmethyl, no persistent inhibition of anaerobic or aerobic nitrogen fixation (C2H2-reduction) was detected . Ammonification, nitrification, and mineralization of soluble starch were also not influenced . The mineralization of cellulose in compost soil (Ct = 13.59%) was temporarily delayed; however, this delay was later compensated for by a higher mineralization rate . The colonization density of fungi on soil particles and the numbers of bacteria, actinomycetes, and fungi were not negatively influenced . Chlorflurenol-methyl does not significantly influence these microbiological processes and populations in the soil. Z Gastroenterol, 1982 Jan, 20(1), 33 - 9 {Bacterial colonization following resective and non-resective stomach-surgery (author's transl)}; Falter E et al.; Studies on why there is a higher disposition of carcinoma developing in the residual portion of the stomach of patients having undergone resections have led to the assumption that bacterial colonization constitutes a co-carcinogenic factor . It has been the purpose of this investigation to compare the ensuing bacterial growth following resective and nonresective stomach surgery . 120 Sprague-Dawley rats were divided into six groups: 1) control group: laparotomy . (2)SPV: with assured preservation of the antrum innervation . 3) SPV + Pypl.: the pyloroplasty was performed according to the Heinecke-upsilon . Mikulicz method . 4) TV + Pypl.: abdominal severance of the trunci nervi vagi . 5) BII: antecolonic without enteroanastomosis . 6) TV + BII . Eight months postoperative a smear was obtained under general anaesthesia from the transition segment between the fundus and antrum or at the site of the anastomosis . Tests for aerobic and anaerobic bacteria as well as cultures for fungi were begun . The control and SPV + Pypl . groups did not differ significantly in total bacteria count and in the ratio of nitrobacter . In contrast, the SPV group without pyloroplasty displayed an approximately tenfold higher concentration of nitrobacters--an amount equivalent to the sum of nitrobacters in the two resection techniques . The TV + BII group had a threefold higher total bacteria count than the BII group . According to our studies, a reduced stomach acid production, the bile secretion reflux and more importantly, a retarded food passage promote intragastric bacterial growth thus expediting the formation of intragastric carcinogenic nitrosamines. J Biol Chem, 1981 Nov 10, 256(21), 10834 - 6 Oxidation of ammonia by Nitrosomonas europaea . Definite 18O-tracer evidence that hydroxylamine formation involves a monooxygenase; Hollocher TC et al.; 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 nitrite, and that NH4+ yields NH2OH by way of a monooxygenase reaction involving direct insertion of O from O2 . The oxidation of NH4+ and NH2OH must be functionally linked in N . europaea, inasmuch as the reducing equivalents required by the monooxygenase to reduce the second atom of O2 to water can arise only through the concomitant oxidation of NH2OH. Arch Environ Contam Toxicol, 1981 Jul, 10(4), 437 - 49 Effects of pesticides on soil microflora using dalapon as an example; Greaves MP et al.; Effects of the herbicide dalapon on the soil microflora are evaluated . Measurements were made on populations and pure cultures of micro-organisms, dehydrogenase and phosphatase, soil respiration, and nitrogen transformations . At normal concentrations of 2.6 and 26 ppm, dalapon had little effect and is unlikely to harm the soil microflora or soil fertility . At abnormal concentrations of 266 and 2,660 ppm, marked effects occurred on the microflora and its activities . In one soil, 2,660 ppm dalapon significantly increased production of ammonium-nitrogen; nitrification was almost totally inhibited in this soil . The results are discussed in terms of the validity of the tests for detecting effects of pesticides on the soil microflora . Some problems, particularly of data interpretation and evaluation, are high-lighted. Can J Biochem, 1981 Jul, 59(7), 484 - 8 A partial resolution and reconstitution of the ammonia-oxidizing system of Nitrosomonas europaea: role of cytochrome c554; Suzuki I et al.; 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 reductase activity of the membrane fraction increased with the addition of cytochrome c554, but the oxidation of hydroxylamine to nitrite required a further addition of cytochrome c552 . The ammonia oxidation by the membrane plus cytochrome c554 was affected by the concentration of phosphate and the addition of bovine serum albumin, spermine, or MgCl2. Can J Biochem, 1981 Jul, 59(7), 477 - 83 Cell-free ammonia-oxidizing system of Nitrosomonas europaea: general conditions and properties; Suzuki I et al.; 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 . Kinetic experiments showed a partial reduction of cytochrome c preceding the initiation of oxygen consumption due to ammonia oxidation. Rev Argent Microbiol, 1981 Jan-Apr, 13(1), 1 - 8 {Effect of atrazine, linuron and 2, 4-D amine on various biological properties of a soil sample . I - Field trial}; Frioni L; Herbicides have a considerable influence on soil microorganisms and soil biochemistry . These influences are likely to be reflected in soil fertility and plant growth . The effects of atrazine, linuron and 2,4-D amine were studied on soil microflora in a field trial with sorghum in Rio Cuarto, Argentina . Atrazine and linuron were applied before sowing and before emergency, and 2-4,-D amine as post-emergence herbicide . Dehydrogenase activity with TTC (tri-Cl-phenyl-tetrazolium) as electron acceptor, nitrogen mineralization by the steam-distillation method (ammonia and nitrate) and enumerations of cellulose-decomposing microorganisms and dinitrogen fixing genus Azotobacter on selective mediums, were studied . The dehydrogenase activity did not show conclusive effects of herbicide action . The small differences at 20 and 71 days after sowing, fluctuated around the control value . The nitrogen mineralization was also barely affected by treatments . At 20 days after sowing, all plots with herbicide accumulated less mineral nitrogen than the control, but only those treated atrazine before emergence (2 kg/ha) differed significantly (5%) . At 71 days a small stimulation of nitrification by linuron was observed . These differences disappeared at the end of the trial (3 1/2 months) . The microbial population of cellulose decomposers was very sensitive to herbicides . This restriction seems to depend on unfavorable food conditions for these microorganisms in a soil without weeds, or it is due to enzyme inhibition by pesticides . This group was inhibited by all treatments in the same manner at flowering time . The nitrogen fixing Azotobacter, which is stimulated in the rhizosphere of grasses, was not affected by these chemicals. Folia Microbiol (Praha), 1981, 26(3), 243 - 52 Effect of some sulphur compounds on soil microflora of spruce rhizosphere; Lettl A; The effect of a long-term application of sulphite, thiosulphate and sodium sulphate on the soil microflora and spruce seedlings was investigated in a pot experiment . Sulphur compounds decreased the concentration of bacteria, including thiobacilli, increased the concentration of microscopic fungi and sulphate-reducing bacteria; they inhibited respiration, nitrification and oxidation of thiosulphate, stimulated ammonification and oxidation of elemental sulphur . In certain cases the spruce rhizosphere exhibited just the opposite effect . In the rhizosphere the sulphate-reducing bacteria was suppressed together with thiobacilli, whose unit oxidative activity increased substantially . Growth of seedlings was inhibited by sulphite and stimulated by thiosulphate and sulphate . Sulphite, the effects of which were similar to those of sulphur dioxide immissions, was the most effective compound . In regions influenced by immissions the soil is apparently intoxicated by the absorbed sulphite. J Biochem (Tokyo), 1981 Jan, 89(1), 265 - 73 Molecular and enzymatic properties of "cytochrome aa3"-type terminal oxidase derived from Nitrobacter agilis; Yamanaka T et al.; Cytochrome c oxidase (cytochrome aa3-type) {EC 1.9.3.1} was purified from Nitrobacter agilis to an electrophoretically homogeneous state and some of its properties were studied . The enzyme showed absorption peaks at 422, 598, and 840 nm in the oxidized form, and at 442 and 606 nm in the reduced form . The CO compound of the reduced enzyme showed peaks at 436 and 604 nm, and the latter peak had a shoulder at 599 nm . The enzyme possessed 1 mol of heme a and 1.6 g-atom of copper per 41,000 g, and was composed of two kinds of subunits of 51,000 and 31,000 daltons . These results show that the structurally minimal unit of the enzyme molecule is composed of one molecule each of the two subunits and contains 2 molecules of heme a and 2-3 atoms of copper . the enzyme rapidly oxidized ferrocytochromes c of several eukaryotes as well as N . agilis ferrocytochrome c-552 . The reactions catalyzed by the enzyme were strongly inhibited by KCN . The reduction product of oxygen catalyzed by the enzyme was concluded to be water on the basis of the ratio of ferrocytochrome c oxidized to molecular oxygen consumed. Acta Microbiol Pol, 1981, 30(3), 259 - 72 Nitrification of industrial waste-waters with high nitrogen concentration in aerated packed-bed reactors; Krogulska B et al.; The use of a two-step aerated packed-bed reactor yielded 99% nitrification of inorganic nitrogenous wastes carrying 800 to 1,300 mg N/l (COD of the wastes 55 mg O2/1) . The beds were aerated with air enriched in CO2 pH values between the units were routinely adjusted . The efficiency of nitrification was 33 mg N/l/h . A change of the composition of the wastes to nitrogenous-organic (COD 1,200 mg O2/l) caused a drop in the efficiency of nitrification to 24 mg N/l/h and the subsequent introduction of a three-step system . Concomitant COD reduction was 85% with 73% reduction occurring in the first bed . The number of auto- and heterotropic bacteria in the nitrogenous-organic wastes and effluents from the separate beds were determined. Aust J Biol Sci, 1981, 34(5-6), 527 - 39 Some properties of glutamine synthetase from the nitrifying bacterium Nitrosomonas europaea; Bhandari B et al.; 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 biosynthetic and gamma-glutamyltransferase (EC 2.3.2.2) assays . The molecular weight of the enzyme preparation was approximately 440 000 . The gamma-glutamyltransferase activity was markedly inhibited by alanine, lysine, glutamic acid, aspartic acid and serine and to a lesser extent by glycine, asparagine, arginine and histidine . Except for tryptophan and cystine, the gamma-glutamyltransferase activity was inhibited to a greater extent by these amino acids than was the biosynthetic activity . Different pairs of amino acids in various combinations resulted in a cumulative inhibition of enzyme activity determined by either method . Of the various nucleotides tested, the gamma-glutamlytransferase activity of the enzyme was inhibited to a greater extent by di- and triphosphate nucleotides--IDP, CDP, UDP, ITP, CTP, TTP and ATP (except GDP and GTP) than by monophosphate nucleotides except AMP . Saturating concentrations of pyruvate, oxalate, oxaloacetate and alpha-ketoglutarate depressed enzyme activity . Various combinations of amino acids with adenine nucleotides exerted cumulative inhibitory effects on the transferase activity. Arch Microbiol, 1980 Dec, 128(2), 204 - 8 Serological studies on lithotrophic, ammonia oxidizing bacteria; Wullenweber M et al.; 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 cases cross-reactions between cells of the Nitrosovibrio strains and the anti-Nitrosospira- as well as the anti-Nitrosococcus-antisera could be observed . The interpretation of the results obtained with the Nitrosomonas group was complicated by the fact that all strains showed positive zero titers with the control sera . In seven cases lipopolysaccharides were isolated and tested in the passive hemagglutination test to their cross-reactivity with the above mentioned antisera . Hemagglutination could only be observed in the homologous system, cross-reactivity was never expressed. Can J Microbiol, 1980 Nov, 26(11), 1270 - 4 Cytochrome oxidase of Nitrobacter agilis: isolation by hydrophobic interaction chromatography; Chaudhry GR et al.; Cytochrome oxidase has been purified from Nitrobacter agilis using hydrophobic interaction chromatography . The purified preparation contained 3-5% phospholipid and migrated as a single band during polyacrylamide gel electrophoresis under nondissociating conditions, but appeared as three bands in the presence of sodium dodecyl sulfate and 6 M urea . These three bands corresponded to molecular weights of 37 000, 25 000, and 13 000 . The absorption spectra of cytochrome oxidase isolated from Nitrobacter were similar to those reported for a-type cytochrome oxidase from other sources and exhibited absorption maxima at 420 and 600 nm when oxidized and 443 and 606 nm when reduced . The purified enzyme reacted both with horse heart and Nitrobacter cytochrome c . The enzymatic activity depended upon the pH of reaction mixture, with the maximum activity at pH 6.5 and 7.5 for Nitrobacter and horse heart cytochrome c, respectively . The activity of the purified enzyme was inhibited by cyanide, azide, and diethyl dithiocarbamate. Can J Microbiol, 1980 Sep, 26(9), 1114 - 9 Sequential nitrification by an Alcaligenes sp . and Nitrobacter agilis; Castignetti D et al.; The ecological importance of heterotrophic nitrification has been difficult to assess because of low levels of nitrification associated with this phenomenon . Nitrification by a soil isolate, an Alcaligenes sp., which oxidizes pyruvic oxime to produce up to 1867 mg nitrite-nitrogen/L, is described . Sequential nitrification with the chemoautotroph Nitrobacter agilis, ATCC 14123, resulted in nitrate accumulation and a concomitant decrease of the nitrite produced by the Alcaligenes sp . when the bacteria were jointly cultured . The ecological significance of such a sequential system is discussed. Mikrobiologiia, 1980 May-Jun, 49(3), 531 - 4 {Microfloral study of the active ooze in the 3-stage treatment of sewage}; Ten Khak Mun; The work was done with the microflora of active sludge from purifying constructions of a fattening plant which consisted of three aerotanks arranged one after another . In all stages of the constructions, the biocenosis of active sludge was represented by identical groups of microorganisms whose quantitative composition was the same in all of the stages . At the same time, the oxidative activity of the cenoses in sludge and the activity of certain enzymes were maximal in the second stage . The oxidation activity of microorganisms in the first stage was limited by the concentration of dissolved oxygen . The growth of microorganisms in the third stage was limited by the content of organic substances in the sewage, and the processes of nitrification here were more intensive . The results have shown that it is expedient to have a three-stage system of purifying constructions and to cultivate specific biocenoses in each of th