Denitrifying

Biochim Biophys Acta, 1982 Sep 15, 681(3), 459 - 68
Discrimination of ascorbate-dependent nonenzymatic and enzymatic, membrane-bound reduction of nitric oxide in denitrifying Pseudomonas perfectomarinus; Zumft WG et al.; The marine nitrite-respiring (denitrifying) bacterium, Pseudomonas perfectomarinus, catalyzes by a membrane-bound enzyme the reduction of nitric oxide to nitrous oxide with ascorbic-reduced phenazine methosulfate as electron donor . The entire nitric oxide-reducing capability of a cell-free system was membrane bound and this process was studied with respect to pH and substrate dependency . The enzymatic process was perturbed by an identical nonenzymatic reduction by iron(II) ascorbate in neutral to alkaline aqueous solution . 2 mol nitric oxide and 1 mol ascorbate were consumed per mol nitrous oxide formed . Enzymatic and nonenzymatic processes were discriminated by their differential behavior towards pH and metal-chelating agents . The pH optimum for the enzymatic and nonenzymatic reaction was 5.2 and greater than 7.0, respectively . EDTA (10 mM) inhibited the nonenzymatic reduction completely without interfering with the membrane-bound activity . The nonenzymatic system mimics the reaction of nitric oxide reductase and could serve as a model to study the formation of the N-N bond in denitrification . Enzymatic generation of nitric oxide by cytochrome cd and subsequent nonenzymatic reduction to nitrous oxide simulate an overall quasi-enzymatic nitrous oxide formation by cytochrome cd . The nonenzymatic reduction of nitric oxide might have occurred in previous work due to the ubiquitous use of ascorbate in studies on nitrite respiration and the likelihood of adventitious iron in biological samples.

Farmaco {Sci}, 1982 Jul, 37(7), 463 - 74
The reductive metabolism of the nitroaromatic flukicidal agent nitroxinil by liver microsomal cytochrome P-450; Maffei Facino R et al.; Hepatic biotransformation of the flukicidal agent nitroxynil (3-iodo-4-hydroxy-5-nitrobenzonitrile) (I) has been studied with rat liver subcellular fractions as the source of enzymes: two metabolites, 3-iodo-4--hydroxy-5-aminobenzonitrile (II) and 3-iodo-4-hydroxy-5-nitrobenzamide (III) have been identified by standard analytical techniques (TLC, GLC and MS) . The nitroaromatic reduction product (II) is formed in the hepatocyte in a process in which cytosol and endoplasmic reticulum enzymes cooperate . This formation is maximal in anaerobic conditions, but takes also place aerobically and in the absence of electrogenic cofactors . Cytochrome P-450 plays a major role in the denitrification process, and consequently could be the cellular site most exposed to damage by the intermediate arylhydroxylamine formed by reduction.

J Bacteriol, 1982 Jul, 151(1), 162 - 71
Properties of dissimilatory nitrate reductase purified from the denitrifier Pseudomonas aeruginosa; Carlson CA et al.; Dissimilatory nitrate reductase was purified to homogeneity from anaerobic cultures of the denitrifying bacterium Pseudomonas aeruginosa . The following procedures were used in the rapid isolation of this unstable enzyme: induction by nitrate in semianaerobic cell suspension, heat-stimulated activation and solubilization from the membrane fraction, and purification by hydrophobic interaction chromatography . The molecular weight of the purified enzyme was estimated by nondenaturing polyacrylamide gel electrophoresis, sucrose density gradient sedimentation, and gel filtration chromatography . Subunit molecular weights were estimated by electrophoresis in sodium dodecyl sulfate-polyacrylamide gels . The active enzyme monomer, with a molecular weight of 176,000 to 260,000 (depending upon the method of determination), was composed of subunits with molecular weights of approximately 64,000 and 118,000 . The monomer aggregated to form an inactive tetramer of about 800,000 molecular weight . Purified enzyme exhibited a broad pH optimum, between 6.5 and 7.5 . Kinetic studies showed that the apparent Km was 0.30 mM for nitrate, and 2.2 to 2.9 microM for dithionite-reduced benzyl viologen . Azide was an effective inhibitor: the concentration required for half-maximal inhibition was 21 to 24 microM . Azide inhibition was competitive with nitrate (Ki = 2.0 microM) but uncompetitive with reduced benzyl viologen (Ki = 25 microM) . Based upon spectral evidence, the purified molybdo-enzyme had no associated cytochromes but did contain nonhaem iron that responded to dithionite reduction and nitrate oxidation . The enzyme that was purified after being heat solubilized from membranes had properties essentially identical to those of the enzyme that was purified after deoxycholate solubilization.

Eur J Biochem, 1982 Jun 15, 125(1), 189 - 95
Purification and characterization of the cytochrome c oxidase from Rhodopseudomonas sphaeroides; Gennis RB et al.; When grown aerobically in the dark, Rhodopseudomonas sphaeroides develops a respiratory chain similar to that in mitochondria and the photosynthetic apparatus is suppressed . The aa3-type cytochrome c oxidase from Rps . sphaeroides has been purified in Triton X-100 by affinity chromatography with Sepharose 4B coupled to yeast cytochrome c . The oxidase contains 14 nmol heme a/mg protein and is composed of three polypeptide subunits with relative molecular masses of 45000, 37000 and 35000 . The enzyme is highly active in the presence of detergents, with a maximal velocity of 300 s-1/mol oxidase using either yeast or horse-heart cytochrome c . The Rps . sphaeroides oxidase is cross-reactive with antibodies directed against the oxidases from Paracoccus denitrificans and Saccharomyces cerevisiae . A particularly close relationship is indicated in the case of P . denitrificans . The Rps . sphaeroides oxidase has been incorporated into phospholipid vesicles . The resulting oxidase in these vesicles demonstrates high enzymatic activity and a respiratory control ratio of 5 . Using these vesicles, no evidence for proton extrusion accompanying cytochrome c oxidation was observed . The data suggest that the Rps . sphaeroides oxidase does not function as a proton pump.

J Biol Chem, 1982 May 25, 257(10), 5576 - 8
Solubilized cytochrome c oxidase from Paracoccus denitrificans is a monomer; Ludwig B et al.; Cytochrome c oxidase purified from the bacterium Paracoccus denitrificans was analyzed by analytical ultracentrifugation . In the detergent octyltetra/pentaoxyethylene (C8E45), the isolated enzyme exhibits a molecular weight of 79,000 to 84,000 . The detergent-solubilized enzyme is thus a monomer which contains one copy of each of the two subunits.

Nucleic Acids Res, 1982 May 11, 10(9), 2963 - 70
The 5S ribosomal RNAs of Paracoccus denitrificans and Prochloron; MacKay RM et al.; The nucleotide sequences of the 5S rRNAs of Paracoccus denitrificans and Prochloron sp . are (formula: see text), respectively . Specific phylogenetic relationships of P . denitrificans with purple non-sulphur bacteria, and of Prochloron with cyanobacteria are demonstrated, and unique features of potential secondary structure are described.

J Biol Chem, 1982 May 10, 257(9), 4705 - 8
Positional isotopic equivalence of nitrogen in N2O produced by the denitrifying bacterium Pseudomonas stutzeri . Indirect evidence for a nitroxyl pathway; Garber EA et al.; During the concomitant reduction of {15N}nitrite and 14NO, the denitrifying bacterium Pseudomonas stutzeri produced considerable amounts of isotopically mixed N2O (14,15N2O) but did not isotopically intermix the nitrite and NO pools (Garber, E . A . E., and Hollocher, T . C . (1981) J . Biol . Chem . 256, 5459-5465) . It was determined that the mass spectrometric abundance of 14N15NO was about equal to that of 15N14NO in 14,15N2O by examination of the abundances of 14NO+, 15NO+, and 15N2+ that arose from the fragmentation of N2O+ species in the mass spectrometer . This positional isotopic equivalence requires that N2O arose from {15N}nitrite and 14NO by a process in which loss of oxygen occurred with equal probability from 15N and 14N precursors and suggests that at some point the precursors were identical if monomeric or effectively symmetrical if dimeric . One pathway, which is consistent with the available data and for which there is chemical precedence, is the reduction of nitrite and NO to nitroxyl (NOH or HNO), dimerization of free nitroxyl to a dinitrogen intermediate of short half-life, and dehydration of this intermediate to form N2O.

Ann Microbiol (Paris), 1982 May-Jun, 133(3), 471 - 88
{Numerical taxonomy of a thermophilic "Bacillus" species isolated from West African rice soils (author's transl)}; Garcia JL et al.; Fifty-seven strains of endospore-forming thermophilic bacteria, 37 of which were capable of denitrification, were isolated from rice soils of West Africa . They were compared with 17 strains of similar bacteria from culture collections, utilizing a total of 123 morphological, physiological and biochemical characteristics . A numerical analysis was performed using the complete linkage-clustering method and the Khi2 test . Seventy-five percent (55 strains) could be included in 12 groups at a taxonomic distance of 0.015 . Wild strains of denitrifiers issued in phenons 8 to 12 and strains of phenon 4 (not denitrifying) were related to the named strains of phenons 1 and 7 (Bacillus stearothermophilus) . Twenty-two wild strains, and 5 strains from culture collections, were only thermotolerating without growth at 65 degrees C . The strains of phenon 3 were related to the 3 named strains of B . coagulans . Phenons 5 and 6 were composed of strains related to B . circulans . The strains of phenon 2 denitrified and showed a swollen central endospore; they were closely related to B . brevis . The denitrifying thermophilic strains isolated from rice soils (phenons 8 to 12) were related to the first group (B . kaustophilus) of Walker and Wolf but their base compositions of DNA were significantly different from those found for the reference strains.

Antonie Van Leeuwenhoek, 1982 May, 48(2), 131 - 43
Oxygen tolerance of strictly aerobic hydrogen-oxidizing bacteria; Wilde E et al.; Growth of various bacteria, especially aerobic hydrogen-oxidizing bacteria, in the presence of 2 to 100% (v/v) oxygen in the gas atmosphere was evaluated . The bacterial strains included Alcaligenes eutrophus, A . paradoxus, Aquaspirillum autotrophicum, Arthrobacter spec . strain 11 X, Escherichia coli, Arthrobacter globiformis, Nocardia opaca, N . autotrophica, Paracoccus denitrificans, Pseudomonas facilis, P . putida, and Xanthobacter autotrophicus . Under heterotrophic conditions with fructose or gluconate as substrates neither colony formation on solid medium nor the growth rates in liquid media were drastically impaired by up to 100% oxygen . In contrast, autotrophic growth--with hydrogen, carbon dioxide and up to 80% oxygen in the gas atmosphere--was strongly depressed by high oxygen concentrations . However, only the growth rate, not the viability of the cells, was decreased . Growth retardation was accompanied by a decrease of hydrogenase activity.

J Bacteriol, 1982 Apr, 150(1), 100 - 4
Fixation of dinitrogen derived from denitrification of nitrate in a photosynthetic bacterium, Rhodopseudomonas sphaeroides forma sp . denitrificans; Dunstan RH et al.; Studies with 15N demonstrated that the phototrophic bacterium Rhodopseudomonas sphaeroides forma sp . denitrificans strain IL106 cannot assimilate NO-3 but rather denitrifies it to N2 . This strain also fixed N2 into cell protein, although nitrogenase activity was partially inhibited in the presence of NO-3 . Strain IL106 did not assimilate NO-3, but growing cultures and washed cell suspensions incorporated the tracer from 15NO-3 via denitrification to 15N2 and then via nitrogenase into cell nitrogen . This incorporation was inhibited in cells supplied with NH4+ or in the absence of light, thus confirming the participation of nitrogenase in the assimilation of nitrogen from nitrate . This represents a novel type of N2 recycling in a photodiazotrophic denitrifying bacterium.

J Gen Microbiol, 1982 Apr, 128 (Pt 4), 731 - 45
Numerical classification of some Rhodococci, Corynebacteria and related organisms; Goodfellow M et al.; Nineteen strains of Corynebacterium sensu stricto, 23 received as Corynebacterium equi or Rhodococcus equi, marker cultures of Arthrobacter, Brevibacterium, Bacterionema matruchotii, Cellulomonas flavigena, Kurthia zopfii, Listeria denitrificans, Microbacterium lacticum, Rhodococcus rubropertinctus and 88 representatives of Mycobacterium, Nocardia, Rhodococcus and the 'aurantiaca' taxon were the subject of numerical phenetic analyses using 92 characters . The data were examined using the simple matching (SSM) and Jaccard (SJ) coefficients and clustering was achieved using the average linkage algorithm . With a single exception, strains containing meso-diaminopimelic acid, arabinose, galactose and mycolic acids were recovered in five aggregate clusters corresponding to Corynebacterium sensu stricto, Mycobacterium, Nocardia, Rhodococcus and the 'aurantiaca' taxon . Most of the Corynebacterium (Rhodococcus) equi strains formed a good taxospecies which included the type strain of Corynebacterium hoagii . The numerical data, and the results of earlier chemical and genetical studies, also provide sufficient evidence for the transfer of Bacterionema matruchotii to Corynebacterium sensu stricto as Corynebacterium matruchotii comb.nov . and for the recognition of Rhodococcus globerulus sp.nov . for some strains previously classified as Rhodococcus rubropertinctus (Hefferan) Goodfellow & Alderson . The classification of the remaining marker strains correlates well with other major developments in coryneform taxonomy.

Biochim Biophys Acta, 1982 Mar 4, 701(3), 305 - 17
Isolation and characterization of a protein with cyanide-sensitive superoxide dismutase activity from the prokaryote, Paracoccus denitrificans; Vignais PM et al.; 1 . A protein with cyanide-sensitive superoxide dismutase activity was isolated from the prokaryote Paracoccus denitrificans . 2 . This enzyme, present in low amount in the cell, represented not more than 10% of the total cellular superoxide dismutase activity . It was obtained in a form which was 20-40-times less active than the main superoxide dismutase of P . denitrificans which is a manganese-containing enzyme . 3 . It was a soluble monomeric enzyme, highly negatively charged (pI = 4.8), with an apparent molecular weight of 33,000 . 4 . Cyanide sensitivity was observed by NMR assay, enzyme assay and by staining the protein for superoxide dismutase activity on polyacrylamide electrophoretogram . KCN was shown to be a competitive inhibitor of this dismutase, with an inhibitor constant of 0.15 mM . 5 . From the amino acid analysis, S delta Q values lower than 100 were obtained with copper-containing proteins such as the subunit II of cytochrome oxidase from P . denitrificans (69), the azurin from P . denitrificans (77), the bacteriocuprein from Photobacter leiognathi (71); with iron and manganese superoxide dismutases (40-88), and with some eukaryotic copper/zinc dismutases of fish origin (55-82).

J Biol Chem, 1982 Feb 25, 257(4), 1579 - 82
The cytochrome c oxidase of Paracoccus denitrificans pumps protons in a reconstituted system; Solioz M et al.; The purified two-subunit cytochrome c oxidase of Paracoccus denitrificans was reconstituted into phospholipid vesicles having a high internal buffering capacity and exhibiting a respiratory control index greater than 6.6 . With these proteoliposomes, pH changes of the suspending medium were monitored in response to reductant pulses in the presence of valinomycin and potassium . When reduced cytochrome c was added to allow for a limited number of turnovers (2-12), a net acidification of the extravesicular space could be observed . This apparent proton ejection by the vesicles was abolished by inhibition of the oxidase with azide, by bypassing the oxidase with ferricyanide, or by preventing charge compensation by omitting valinomycin . Addition of uncoupler led to an alkalinization, rather than an acidification, of the extravesicular space in response to reduced cytochrome c . We thus conclude that cytochrome c oxidase of P . denitrificans is a proton pump . Under the conditions described here, an apparent stoichiometry of 0.6 proton ejected/electron was obtained by extrapolation to zero turnovers.

Folia Microbiol (Praha), 1982, 27(6), 460 - 4
Tetraphenylborate-sensitive electrode for measuring membrane potential; Karlovsky P et al.; The paper describes the construction of a new type of ion-selective electrode sensitive to tetraphenylborate (TPB-) and its electric characteristics . The electrode responds to increasing concentrations of the TPB- anion in accordance with the Nernst equation and can be used down to 0.1 microM concentration . The applicability of the electrode for measuring the membrane potential (positive inside) was proved in inside-out oriented membrane vesicles derived from Paracoccus denitrificans . The calculated values were 175 +/- 12 mV with NADH and 180 +/- 6 mV with succinate.

Antonie Van Leeuwenhoek, 1982, 48(6), 531 - 44
The pathway of nitrogen and reductive enzymes of denitrification; Hollocher TC; Some recent studies on the pathway of nitrogen and the reductases of denitrification are reviewed . The available evidence suggests that while the intermediates of denitrification can remain enzyme-bound (presumably to nitrite reductase) prior to formation of N2O, NO and nitroxyl (HNO) can be released in part by certain bacteria . Release of NO is recognized by a nitrite/NO-15N exchange reaction and isotopic scrambling in product N2O; release of nitroxyl by Pseudomonas stutzeri is recognized by isotopic scrambling of nitrite and NO in product N2O in absence of exchange and affords evidence that the first N-N bond forms in denitrification at the N1+ redox level . The recent purification and partial characterization of nitrous oxide reductase are described . The ability of the dissimilatory nitrite reductase to activate nitrite for nitrosyl transfer affords a new chemical probe into the mechanism of action of this central enzyme . It would appear that reduction of nitrite is subject to electrophilic catalysis . 18O studies show that dissociation of nitrite from nitrite reductase can be slow relative to competing reduction or nitrosyl transfer.

Antonie Van Leeuwenhoek, 1982, 48(6), 585 - 607
Evolution of bacterial denitrification and denitrifier diversity; Betlach MR; Little is known about the role of nitrate in evolution of bacterial energy-generating mechanisms . Denitrifying bacteria are commonly regarded to have evolved from nitrate-respiring bacteria . Some researchers regard denitrification to be the precursor of aerobic respiration; others feel the opposite is true . Currently recognized denitrifying bacteria such as Hyphomicrobium, Paracoccus, Pseudomonas and Thiobacillus form a very diverse group . However, inadequate testing procedures and uncertain taxonomic identification of many isolates may have overstated the number of genera with species capable of denitrification . Nitrate reductases are structurally similar among denitrifying bacteria, but distinct from the enzymes in other nitrate-reducing organisms . Denitryfying bacteria have one of two types of nitrite reductase, either a copper-containing enzyme or an enzyme containing a cytochrome cd moiety . Both types are distinct from other nitrate reductases . Organisms capable of dissimilatory nitrate reduction are widely distributed among eubacterial groups defined by 16S ribosomal RNA phylogeny . Indeed, nitrate reduction is an almost universal property of actinomycetes and enteric organisms . However, denitrification is restricted to genera within the purple photosynthetic group . Denitrification within the genus Pseudomonas is distributed in accordance with DNA and RNA homology complexes . Denitrifiers seem to have evolved from a common ancestor within the purple photosynthetic bacterial group, but not from a nitrate-reducing organism such as those found today . Although denitrification seems to have arisen at the same time as aerobic respiration, the evolutionary relationship between the two cannot be determined at this time.

Antonie Van Leeuwenhoek, 1982, 48(6), 569 - 83
Denitrification: ecological niches, competition and survival; Tiedje JM et al.; Organisms with the denitrification capacity are widely distributed and in high density in nature . It is not well understood why they are so successful . A survey of denitrifying enzyme content of various habitats is presented which indicates a role of carbon and oxygen, but not nitrate, in affecting denitrifier populations . It is suggested that organic carbon is more important than oxygen status in determining denitrifying enzyme content of habitats . In low oxygen environments, denitrifiers compete with organisms that dissimilate nitrate to ammonium, a process which conserves nitrogen . The energetic and kinetic parameters that affect this competition are evaluated . The latter is examined using Michaelis-Menten theoretical models by varying Vmax, Km, and So (substrate concentration) for the two competing populations . The outcome predicted by these models is presented and discussed in relation to previous data on population densities and Km values for representatives of these competing groups . These models suggest the conditions required to achieve changes in partitioning between the two fates of nitrate . These considerations are important if one is to be able to evaluate and successfully "manage" the fate of nitrate in any habitat.

Antonie Van Leeuwenhoek, 1982, 48(6), 545 - 53
The bioenergetics of denitrification; Stouthamer AH et al.; In anaerobically grown Paracoccus denitrificans the dissimilatory nitrate reductase is linked to the respiratory chain at the level of cytochromes b . Electron transport to nitrite and nitrous oxide involves c-type cytochromes . During electron transport from NADH to nitrate one phosphorylation site is passed, whereas two sites are passed during electron transport from NADH to oxygen, nitrite and nitrous oxide . The presentation of a respiratory chain as a linear array of electron carriers gives a misleading picture of the efficiency of energy conservation since the location of the reductases is not taken into account . For the reduction of nitrite and nitrous oxide, protons are utilized from the periplasmic space, whereas for the reduction of oxygen and nitrate, protons are utilized from the cytoplasmic side of the inner membrane . Evidence for two transport systems for nitrate was obtained . One is driven by the proton motive force; this system is used to initiate nitrate reduction . The second system is a nitrate-nitrite antiport system . A scheme for proton translocation and electron transport to nitrate, nitrite, nitrous oxide and oxygen is presented . The number of charges translocated across the membrane during flow of two electrons from NADH is the same for all nitrogenous oxides and is 67-71% of that during electron transfer to oxygen via cytochrome o . These findings are in accordance with growth yield studies . YMAX electron values determined in chemostat cultures for growth with various substrates and hydrogen acceptors are proportional to the number of charges translocated to these hydrogen acceptors during electron transport.

Antonie Van Leeuwenhoek, 1982, 48(6), 555 - 67
The physiological genetics of denitrifying bacteria; Carlson CA; The genetics of denitrification is a relatively unexplored area that has great promise . Species of Pseudomonas are probably best suited for study because they are widely found among natural denitrifying populations and are quite readily amenable to genetic analysis . The techniques for mutagenesis and for the exchange of chromosomal genes to characterize mutant strains have been well-developed in P . aeruginosa and are being developed in P . stutzeri . Mutants defective in the denitrification of nitrate, nitrite, and nitrous oxide are now available and will aid in describing the catalytic and regulatory elements of the denitrification pathway.

Folia Microbiol (Praha), 1982, 27(1), 11 - 8
Changes in the cytochrome c content during the aerobic adaptation of Paracoccus denitrificans; Stros M et al.; Concentration of cytochrome c decreases when shaking anaerobically grown cells in a non-growth medium down to 50% of the original amount in the cell, depending on the degree of aeration . Only 10-20% of this amount can be found in the adaptation medium . The main portion of cytochrome c is degraded during the adaptation . Inhibitors of proteinases do not influence the degradation . Addition of mammalian cytochrome c fully prevents the degradation of bacterial cytochrome c but not its release from cells . Potassium hexacyanoferrate(III) exhibits a similar effect as oxygen . The degradation system is probably localized in the periplasmic space of the cells.

Biochemistry, 1981 Dec 22, 20(26), 7528 - 31
Resonance Raman spectra of cytochromes c and b in Paracoccus denitrificans membranes: evidence for heme--heme interactions; Adar F et al.; Resonance Raman (RR) scattering from cytochromes b and c in the bacterium Paracoccus denitrificans was recorded by exciting with the 568.2-, 530.9-, and 520.8-nm lines of a Kr+ laser . The main features of the spectra were similar to those of the analogous cytochrome b-c1 complex derived from pigeon breast mitochondria . Differences in the 1300-cm-1 region were interpreted in terms of marker bands for heme type and spectral coupling of the hemes on the membranes . It is difficult to explain the results without invoking sharing of electronic and vibrational wave functions among the hemes . This conclusion documents the potential to study the physics of electron transport in functioning membrane by monitoring the RR spectra.

Biochim Biophys Acta, 1981 Dec 14, 638(2), 181 - 91
Respiration-driven proton translocation with nitrite and nitrous oxide in Paracoccus denitrificans; Boogerd FC et al.; (1)H+ leads to/electron acceptor ratios have been determined with the oxidant pulse method for cells of denitrifying Paracoccus denitrificans oxidizing endogenous substrates during reduction of O2, NO2- or N2O . Under optimal H+-translocation conditions, the ratios leads to H+/O, H+ leads to/N2O, H+ leads to/NO2- for reduction to N2 and H+ leads to/NO2- for reduction to N2O were 6.0-6.3, 4.02, 5.79 and 3.37, respectively . (2) With ascorbate/N,N,N,'N'-tetramethyl-p-phenylene-diamine as exogenous substrate, addition of NO2- or N2O to an anaerobic cell suspension resulted in rapid alkalinization of the outer bulk medium . H+/N2O, H+/NO2- for reduction to N2 and H+/NO2- for reduction to N2O were -0.84, -2.33 and -1.90, respectively . (3) The H+/oxidant ratios, mentioned in item 2, were not altered in the presence of valinomycin/K+ and the triphenylmethylphosphonium cation . (4) A simplified scheme of electron transport to O2, NO2- and N2O is presented which shows a periplasmic orientation of the nitrite reductase as well as the nitrous oxide reductase . Electrons destined for NO2-, N2O or O2 pass two H+-trans-locating sites . The H+ leads to/electron acceptor ratios predicted by this scheme are in good agreement with the experimental values.

Arch Microbiol, 1981 Dec, 130(4), 307 - 11
Removal of Paracoccus denitrificans outer membrane material by sodium chloride; Hindahl MS et al.; The effects of water washing and NaCl treatment on the cell surface of P . denitrificans were studied . Both treatments caused a release of material from cells . Chemical studies showed that NaCl treatment released material containing components characteristic of outer membrane . This treatment also increased the susceptibility of the organism to lysozyme . Scanning electron microscopy was used to monitor the effects of water washing and NaCl treatment on the cell surface . Both treatments were shown to alter the appearance of the cell surface . The disruptive effects of these procedures were found to be dependent upon the age of the culture.

J Gen Microbiol, 1981 Dec, 127 (Pt 2), 261 - 8
The gradostat: a bidirectional compound chemostat and its application in microbiological research; Lovitt RW et al.; A multistage continuous culture system is described in which solutes are transferred between vessels in opposite directions simultaneously . The system, called a gradostat, produces opposing solute gradients and is a good laboratory model of many natural microbial ecosystems in which solute gradients are important . Theoretical predictions concerning solute transfer were confirmed under steady-state and non steady-state conditions, using a coloured dye . Paracoccus denitrificans grew anaerobically in the gradostat at the intersection between opposing gradients of succinate and nitrate . Opposing gradients of glucose and oxygen separated the growth of a Bacillus sp . (a facultative anaerobe) and Clostridium butyricum (an obligate anaerobe) . Viable counts for both species fell exponentially away from their growth positions at the ends of the gradostat . The potential value of the gradostat and possible alternative conformations are discussed.

Antimicrob Agents Chemother, 1981 Dec, 20(6), 814 - 20
Antibiotic action of pyocyanin; Baron SS et al.; Biologically produced pyocyanin was purified, and the nature of its antibacterial action was determined for several bacteria . The pigment was shown to be bactericidal for all susceptible organisms . The bactericidal effect was dependent upon pyocyanin concentration and resulted in decreases in viability ranging from 1 to 8 log viable cells ml-1 . The gram-positive bacteria were more susceptible as a group to the antibiotic action than were the gram-negative bacteria . All apyocyanogenic pseudomonads tested were totally resistant to the pigment, suggesting that resistance may be a characteristic of the genus . Pseudomonas aeruginosa, the producer organism, was also essentially unaffected by high concentrations of pyocyanin . Facultative anaerobes were twofold or more times resistant to the action of the pigment under fermentative conditions; however, the antibiotic action did not require oxygen since denitrifying bacteria were more susceptible during anaerobic respiration than during aerobic respiration.

Biochim Biophys Acta, 1981 Oct 12, 637(3), 504 - 11
Occurrence of proteins immunoreactive with anti-coupling factor B in phosphorylating membrane preparations; Joshi S et al.; Coupling factor B has been isolated from beef heart mitochondria, apparently in multiple forms which differ in molecular weight and specific activity . Since it has no known intrinsic catalytic activity, detection and quantitation have been based upon the factor B-dependent stimulation of ATP-linked activities in factor B-deficient sub-mitochondrial particles . This communication reports the development of a reliable and more universally applicable enzyme-linked immunosorbent assay (ELISA) for detection and quantitation of factor B in soluble or membranous preparations . The assay requires nanoliter volumes of rabbit antiserum raised against purified factor B and will detect nanogram amounts of the coupling factor . Analysis of beef heart submitochondrial particles using a competitive binding ELISA indicated a factor B content of 0.27 nmol/mg protein, making factor B stoichiometric with F1 (0.3--0.6 nmol/mg) . Furthermore, application of the factor B ELISA has indicated the presence of material cross-reacting with the beef heart factor B-antiserum in phosphorylating membranes from chloroplasts, Escherichia coli, Paracoccus denitrificans and the thermophilic bacterium, PS3 . Negative results were obtained with mitochondria and microsomes from rat liver, purple membranes from Halobium halobacterium and sarcoplasmic reticulum from rabbit skeletal muscle.

J Biol Chem, 1981 Oct 10, 256(19), 10092 - 8
Reaction of oxygen with cytochrome c oxidase from Paracoccus denitrificans; Ludwig B et al.; The reaction of reduced cytochrome c oxidase (EC 1.9.3.1) from Paracoccus denitrificans (American Type Culture Collection 13543) with dioxygen has been followed by laser flash photolysis of the CO derivative . In detergent-stabilized solutions the reaction showed at least two distinct kinetic components, the faster of which was oxygen concentration dependent and had a rate of approximately 60 X 10(6) M-1 s-1 . The slower reaction was independent of oxygen concentration and had a rate of 9 X 10(2) s-1 . These rates are about 1.5 times greater than comparable rates for ox heart oxidase reported by C . Greenwood and Q . H . Gibson (J . Biol . Chem . (1967) 242, 1782-1787) . The kinetic components have markedly different optical spectra which agree precisely in form with those for ox heart enzyme (Greenwood, C., and Gibson, Q . H . (1967) J . Biol . Chem . 242, 1782-1787) but are shifted by 2 nm toward the red . In phospholipid vesicles, the spectral contribution of the faster component was augmented . The dissociation constant for CO at 20 degrees C is 1.6 microM, 6 times greater than for the ox heart enzyme . The bacterial enzyme binds one CO per 2 heme a . The enzyme has an absorption band at 830 nm in the oxidized form similar to that of the ox heart enzyme.

Can J Microbiol, 1981 Sep, 27(9), 878 - 85
Denitrification and dissimilatory nitrate reduction to ammonium in digested sludge; Kaspar HF et al.; Acetylene inhibition and 13N methods were used to assay digested sludge for its potential to denitrify and to reduce nitrate to ammonium . At nitrate concentrations below 10 microM, the reduction of N2O to N2 was not inhibited by acetylene concentrations as high as 80 kPa, though at higher nitrate concentration acetylene was an effective inhibitor . NO, N2O, and N2 were produced immediately after addition of nitrate or nitrite, indicating that denitrifying enzymes were present . NO was maintained at a higher concentration of 2--5 nM, while nitrate or nitrite were being reduced, but this gas was depleted once the ionic N oxide substrates were exhausted . Acetylene had little effect on appearance and disappearance of NO . It was also noted that NO was readily consumed by chemical reactions in the anaerobic sludge . Added N2O was reduced without a lag, but pasteurized samples did not consume N2O although they produced it . Fresh digested sludge reduced 60--70% of the added 13NO3- to 13NH4+ with the rest of the NO3- -N presumably lost to denitrification . This agrees well with the nitrate partitioning observed by the acetylene inhibition method in which 30--40% of the NO3- -N was recovered as N2O . Denitrification capacity persisted in both digested sludge and a methanogenic enrichment culture which had been grown in a chemostat for 2.5 years with acetate and ammonium as the sole carbon and nitrogen source . This suggests that denitrifiers with capacities for alternative anaerobic energy metabolism may be more common than now known.

Biochim Biophys Acta, 1981 Aug 24, 665(2), 270 - 82
Studies on cyclopropane fatty acid synthesis . Correlation between the state of reduction of respiratory components and the accumulation of methylene hexadecanoic acid by Pseudomonas denitrificans; Jacques NA; A delay in the onset of accumulation of methylene hexadecanoic acid could be engendered in Pseudomonas denitrificans growing under limited oxygen conditions when the concentration of citrate but not the concentration of succinate in the medium was increased from 0.1 to 0.5% . Ascorbate, which specifically reduced a cytochrome component possessing a maximum absorbance at 551 nm, partially inhibited the accumulation of methylene hexadecanoic acid under conditions which otherwise led to maximal production . Limiting terminal cytochrome oxidase activity by controlling the oxygen supply, or by the use of low concentrations of the oxidase inhibitors cyanide or azide also prevented the accumulation of the fatty acid regardless of the nature or concentration of carbon source in the medium . Measurement of the levels of ATP, NAD and NADH as well as the steady state of reduction of respiratory components in vivo showed that the onset of accumulation of methylene hexadecanoic acid could be specifically correlated with the state of reduction of respiratory components . The uniqueness of succinate respiration in promoting the synthesis of cyclopropane synthetase (unsaturated-phospholipid methyltransferase (EC 2.1.1.16) under limited oxygen conditions could therefore be assigned to the high degree of oxidation of respiratory components observed under this condition.

Biochim Biophys Acta, 1981 Jul, 636(2), 162 - 7
Copper and manganese electron spin resonance studies of cytochrome c oxidase from Paracoccus denitrificans; Seelig A et al.; The two-subunit cytochrome c oxidase from Paracoccus denitrificans contains two heme a groups and two copper atoms . However, when the enzyme is isolated from cells grown on a commonly employed medium, its electron paramagnetic resonance (EPR) spectrum reveals not only a Cu(II) powder pattern, but also a hyperfine pattern from tightly bound Mn(II) . The pure Mn(II) spectrum is observed at -40 degrees C; the pure Cu(II) spectrum can be seen with cytochrome c oxidase from P . denitrificans cells that had been grown in a Mn(II)-depleted medium . This Cu(II) spectrum is very similar to that of cytochrome c oxidase from yeast or bovine heart . Manganese is apparently not an essential component of P . denitrificans cytochrome c oxidase since it is present in substoichometric amounts relative to copper or heme a and since the manganese-free enzyme retains essentially full activity in oxidizing ferrocytochrome c . However, the manganese is not removed by EDTA and its EPR spectrum responds to the oxidation state of the oxidase . In contrast, manganese added to the yeast oxidase or to the manganese-free P . denitrificans enzyme can be removed by EDTA and does not respond to the oxidation state of the enzyme . This suggests that the manganese normally associated with P . denitrificans cytochrome c oxidase is incorporated into one or more internal sites during the biogenesis of the enzyme.

Biochim Biophys Acta, 1981 May 13, 635(3), 525 - 34
Proton pump coupled to cytochrome c oxidase in Paracoccus denitrificans; van Verseveld HW et al.; The proton translocating properties of cytochrome c oxidase in whole cells of Paracoccus denitrificans have been studied with the oxidant pulse method . leads to H+/2e- quotients have been measured with endogenous substrates, added methanol and added ascorbate (+TMPD) as reductants, and oxygen and ferricyanide as oxidants . It was found that both the observed leads to H+/O with ascorbate (+TMPD) as reductant, and the differences in proton ejection between oxygen-and ferricyanide pulses, with endogenous substrates or added methanol as a substrate, indicate that the P . denitrificans cytochrome c oxidase translocates protons with a stoichiometry of 2H+/2e- . The results presented in this and previous papers are in good agreement with recent findings concerning the mitochondrial cytochrome c oxidase, and suggest unequal charge separation by different coupling segments of the respiratory chain of P . denitrificans.

Can J Microbiol, 1981 May, 27(5), 553 - 7
Ampicillin resistance in Neisseria denitrificans: studies on ampicillin-sensitive enzymes; MacKenzie CR et al.; The beta-lactam sensitivities of enzymes involved in peptidoglycan synthesis were examined in two strains of Neisseria denitrificans having widely disparate degrees of ampicillin sensitivity . One strain of n . denitrificans was 400 times more resistant to ampicillin than the other; the former is known to have altered penicillin-binding proteins . No differences in the levels of sensitivities of total peptidoglycan synthesis as measured by the incorporation of glutamate into peptidoglycan, or of D-alanine carboxypeptidase, were observed between the two strains . However, the rate of glutamate incorporation into peptidoglycan by logarithmic growth phase cells was somewhat less for the ampicillin-resistant cells than for the parent cells.

Biochem J, 1981 Apr 15, 196(1), 311 - 21
Estimation with an ion-selective electrode of the membrane potential in cells of Paracoccus denitrificans from the uptake of the butyltriphenylphosphonium cation during aerobic and anaerobic respiration; McCarthy JE et al.; 1 . Aerobic respiration by cells of Paracoccus dentrificans drives the uptake of the lipophilic cation butyltriphenylphosphonium . Anaerobiosis or addition of an uncoupler of oxidative phosphorylation (carbonyl cyanide p-trifluoromethoxyphenylhydrazone) results in efflux of the cation . Changes in the concentration of butyltriphenylphosphonium in the suspension medium were measured by using an ion-selective electrode, the construction of which is described . 2 . If the uptake of butyltriphenylphosphonium is used as an indicator of membrane potential, then at pH 7.3 an estimate of about 160 mV is obtained for cells of P . dentrificans respiring aerobically in 100 mM-Hepes {4-(2-hydroxyethyl)-1-piperazine-ethanesulphonic acid/NaOH or 100mM-NaH2PO4/NaOH . This potential, however, is decreased by more than 20 mV in reaction media containing a high concentration of phosphate (100 mM) together with at least 1 mM-K+ . 3 . Anaerobic electron transport with NO3-, NO2- or N2O as terminal electron acceptor generates a membrane potential of about 150mV in described suspension media . The presence of these species under aerobic conditions, moreover, has negligible effect upon the extent of uptake of butyltriphenylphosphonium normally driven by aerobic respiration . These data indicate that none of these molecules exert a significant uncoupling effect on the protonmotive force . 4 . No 204Tl+ uptake into respiring cells was detected . This adds to the evidence that 204Tl+ is not a freely permeable cation in bacterial cells and therefore not an indicator of membrane potential as has been proposed . The absence of respiration-driven 204Tl+ uptake indicates that P . denitrificans cells grown under the conditions specified in the present work do not possess K+-transport systems of either the Kdp or TrkA types that have been described in Escherichia coli.

Appl Environ Microbiol, 1981 Mar, 41(3), 705 - 9
Dissimilatory reduction of nitrate and nitrite in the bovine rumen: nitrous oxide production and effect of acetylene; Kaspar HF et al.; 15N tracer methods and gas chromatography coupled to an electron capture detector were used to investigate dissimilatory reduction of nitrate and nitrite by the rumen microbiota of a fistulated cow . Ammonium was the only 15N-labeled end product of quantitative significance . Only traces of nitrous oxide were detected as a product of nitrate reduction; but in experiments with nitrite, up to 0.3% of the added nitrogen accumulated as nitrous oxide, but it was not further reduced . Furthermore, when 13NO3- was incubated with rumen microbiota virtually no {13N}N2 was produced . Acetylene partially inhibited the reduction of nitrite to ammonium as well as the formation of nitrous oxide . It is suggested that in the rumen ecosystem nitrous oxide is a byproduct of dissimilatory nitrite reduction to ammonium rather than a product of denitrification and that the latter process is absent from the rumen habitat.

Biochim Biophys Acta, 1981 Feb 13, 657(2), 411 - 24
A manganese-containing superoxide dismutase from Paracoccus denitrificans; Terech A et al.; A cyanide-insensitive superoxide dismutase (superoxide: superoxide dismutase EC 1.15.1.1) has been isolated from Paracoccus denitrificans, purified to homogeneity and characterized . It is a soluble, manganese-containing protein with an apparent molecular weight of 41 500 +/- 1000 . It is composed of two identical subunits (Mr 23 500) not bound by disulfide linkage . It's isoelectric point is 4.5 . The amino acid composition shows strong similarities with other dimeric procaryotic and with tetrameric mitochondrial Mn-superoxide dismutases . The fully active enzyme contained from 1.34 to 2 gatom Mn/mol enzyme.

Biochim Biophys Acta, 1981 Feb 12, 634(2), 279 - 88
Midpoint potentials of cytochromes in vesicles of anaerobically-grown Paracoccus denitrificans determined by the indirect coulometric titration method; Kula T et al.; 1 . Multiplicity of redox components with spectral properties similar to b-type cytochromes was established in vesicles derived fro anaerobically-grown Paracoccus denitrificans . 2 . Multiplicity of c-type cytochromes was not apparent either from low temperature spectroscopy or potentiometric titrations . 3 . Cytochromes a + a3 and a component, only observable at liquid nitrogen temperature, with a spectral maximum at 582.5 nm were detected . 4 . Redox cycling of electron transport components using the indirect coulometric titration method was a convenient means of pairing redox potentials and was reproducible in total absorbance changes, midpoint potentials and spectral maxima.

J Biol Chem, 1981 Jan 10, 256(1), 278 - 84
Energy coupling to K+ transport in Paracoccus denitrificans; Erecinska M et al.; Paracoccus denitrificans requires potassium for normal growth and transports this cation by at least two systems, one with low (Km approximately 1 to 2 mM) and another with high (Km approximately 0.1 microM) affinity . Neither of the two systems seems to be dependent on periplasmic components since each retains full activity in cells subjected to an osmotic shock . P . denitrificans accumulates potassium at high velocity (270 nmol of K+/min/mg dry weight of cells) and against a large concentration gradient . The intracellular concentration of K+ in media of high osmolarity (about 320 mosmol) is 0.4 M; this gives a concentration gradient {K+}i/{K+}e of greater than or equal to 2 X 10(4) . The uptake of potassium against its concentration gradient requires a source of energy and is eliminated by the addition of uncouplers . The increased rate of energy usage for potassium transport results in an increased rate of ATP synthesis by the respiratory chain and is expressed in enhanced rates of respiration and substrate utilization . The stimulation of respiration is accompanied by increased steady state reduction level of the components of the respiratory chain . The calculations show that two K+ are most likely to be transported per one ATP hydrolyzed.

Folia Microbiol (Praha), 1981, 26(1), 29 - 36
Thiobacilli and sulphate production from inorganic sulphur compounds in upper horizons of spruce forest soils; Lettl A et al.; The species representation of Thiobacilli was investigated in horizons F, H and A of spruce forest at ten localities . Concentrations of Thiobacilli in the selected localities and ability of the soils to oxidize sulphur compounds to sulphate were determined . Horizons F exhibited a high oxidative activity, a lower activity was found in horizon H and the lowest one was detected in horizon A . The activities showed spring and autumn maxima . Horizons F, H and A contained 10(4)--10(5), 10(2)--10(3) and 10(1)--10(3), respectively, Thiobacilli in 1 g dry soil . Thiobacillus thioparus was detected in all three horizons from all localities, T.thiooxidans was found in all horizons F, only in some horizons H and was not detected in horizons A . T.novellus was found only in some samples without any relation to the horizons, T.denitrificans was not detected at all.

Antonie Van Leeuwenhoek, 1981, 47(3), 231 - 43
Cell yield and bioenergetics of Thiomicrospira denitrificans compared with Thiobacillus denitrificans; Timer-ten Hoor A; From cell yields of Thiomicrospira denitrificans grown inthe chemostat at different growth rates under anaerobic conditions a value of 1.4 mM S2O3 = per g dry wt and per h could be calculated for maintenance energy requirements, and of 5.65 dry wt per mole S2O3 = for the true growth yield . Cell yields of Thiomicrospira denitrificans appeared to be almost half of those of Thiobacillus denitrificans . Though in Thiobacillus denitrificans at D = 0.03 h(-1) under anaerobic conditions a value was found of 11.60 g dry wt per mole of thiosulphate used for energetic purposes, a value of 5.72 g dry wt per mole of thiosulphate was found under comparable conditions in Thiomicrospira denitrificans . Under aerobic conditions at D = 0.03 h(-1) values of 18.54 g dry wt per mole of thiosulphate were found in Thiobacillus denitrificans whereas Thiomicrospira denitrificans yielded only 9.38 g dry wt per mole of thiosulphate . As in Thiobacillus denitrificans anaerobic cell yields on sulphide were comparable to those on thiosulphate . Calculations have been made which indicate that the biosynthetic efficiency of Thiomicrospira denitrificans is lower than that of Thiobacillus denitrificans . This can only partly be explained by the absence of adenosine-phosphosulphate (APS) reductase.

Ann N Y Acad Sci, 1981, 361, 330 - 40
The establishment of mitochondria: Paracoccus and Rhodopseudomonas; Whatley FR; Many aerobic bacteria (both facultative and obligate) possess a number of those biochemical features of mitochondria which are concerned with energy metabolism . However, only restricted number, notably Paracoccus denitrificans and Rhodopseudomonas spheroides, have the majority of these features . The theory of endosymbiosis proposes that a primitive eukaryote took up bacteria to yield mitochondria . The present-day Paracoccus then resembles the ancestral bacterium in many respects the primitive amoeba, Pelomyxa palustris, which lacks mitochondria but contains a permanent population of unique symbiotic bacteria, has many of the characteristics of a present-day transitional form . The evolution of mitochondria from endosymbiotic bacteria would involve their integration with the host cell both biochemically and structurally: a number of the intermediate steps are discussed . Attention is drawn to the existence in some ciliates of hydrogenosomes, which function as anaerobic mitochondria.

Biochim Biophys Acta, 1980 Dec 3, 593(2), 224 - 9
A specific uncoupler-binding protein in Tetrahymena pyriformis and Paracoccus denitrificans; Katre NV et al.; The uncoupler of mitochondrial oxidative phosphorylation, 2-nitro-4-azido-carbonylcyanide phenylhydrazone (N3CCP) which is capable of photoaffinity labeling has been used to examine the effect of uncouplers on the energy conserving membrane of Paracoccus denitrificans and Tetrahymena pyriformis . The N3CCP uncouples respiration in P . denitrificans and T . pyriformis cells with U1/2 values of 1.05 microM and 0.24 microM, respectively . Binding studies show the presence of 0.65 +/- 0.05 high affinity sites per cytochrome alpha with Kd of 0.5 +/- 0.1 microM in P . denitrificans membranes and 1.4 +/- 0.2 sites per cytochrome alpha 2 with a Kd of 0.4 +/- 0.1 microM in T . pyriformis membranes . Irradiation of {3H}-N3CCP bound to the membranes leads to a covalent linking of the radioactive uncoupler to a peptide of 10--15 kdaltons as analyzed by SDS-polyacrylamide gel electrophoresis . It is concluded that these two microbial systems contain a specific high affinity uncoupler binding site very similar to that of mammalian mitochondria (Katre, N.V . and Wilson, D.F . (1978) Arch . Biochem . Biophys . 191, 647--656).

Biochim Biophys Acta, 1980 Dec 3, 593(2), 173 - 86
A comparison of the respiratory chain in particles from Paracoccus denitrificans and bovine heart mitochondria by EPR spectroscopy; Albracht SP et al.; A study is presented on the EPR characteristics of the paramagnetic groups in the respiratory chain present in membrane particles of Paracoccus denitrificans, the respiratory system of which is very similar to that in submitochondrial particles from beef heart . All paramagnetic prosthetic groups of the mitochondrial system are also found in the bacterial plasma membrane . Their properties suggest that the respiratory groups are embedded in very similar protein environments in the two systems.

J Bacteriol, 1980 Dec, 144(3), 975 - 82
Inhibition, but not uncoupling, of respiratory energy coupling of three bacterial species by nitrite; Rake JB et al.; The effect of nitrite on respiratory energy coupling of three bacteria was studied in light of a recent report that nitrite acted as an uncoupling agent with Paracoccus denitrificans grown under denitrifying conditions . Our determinations of proton translocation stoichiometry of Pseudomonas putida (aerobically grown), Pseudomonas aeruginosa, and P . denitrificans (grown both aerobically and under denitrifying conditions) showed nitrite inhibition of proton-to-oxidant stoichiometry, but not uncoupling . Nitrite both reduced the H+/O ratio and decreased the rate of proton resorption . Increased proton resorption rates, characteristic of authentic uncoupling agents, were not observed . The lack of enhanced proton permeability due to nitrite was verified via passive proton permeability assays . The H+/O ratio of P . aeruginosa increased when growth conditions were changed from aerobic to denitrifying . This suggested the induction of an additional coupling site in the electron transport chain of denitrifying P . aeruginosa.

Arch Microbiol, 1980 Nov, 128(1), 19 - 25
Substrate level versus oxidative phosphorylation in the generation of ATP in Thiobacillus denitrificans; Aminuddin M; Particulate fractions of Thiobacillus denitrificans catalyse that the phosphorylation of ADP to ATP during the oxidation of various inorganic sulphur compounds or NADH via an electron transport chain . On the other hand, a "soluble" cell-free fraction synthesized ATP from APS and inorganic phosphate . The production of ATP was verified either by the firefly luciferin-luciferase enzyme system or by the incorporation of 32Pi into ATP . During the oxidation of sulphide, sulphite and NADH the production of ATP from ADP by particulate fractions is inhibited by compounds that inhibit electron transfer and by uncouplers of oxidative phosphorylation . However, these compounds had little effect on the production of ATP from AMP during the oxidation of sulphite by the soluble fraction . NADH was the most effective electron donor for oxidative phosphorylation . The soluble fraction contained high activities of ATP sulphurylase, inorganic pyrophosphatase and adenylate kinase but ADP sulphurylase activity was relatively low . The effects of inhibitors on ATP production from APS and Pi are compared with those on adenylate kinase and ATP sulphurylase.

Mikrobiologiia, 1980 Nov-Dec, 49(6), 990 - 4
{Change in the microbiol complexes of soddy podzol soil under the influence of long-term spring wheat monoculture}; Berestetskii OA et al.; The special composition and the properties of microorganisms predominant in the soil and in the rhizosphere of summer wheat were studied in the conditions of monoculture and corp rotation . Noticeable differences were found in the composition of microbial complexes: microorganisms belonging to the genus Arthrobacter prevailed in the conditions of corp rotation, whereas cultures of the genera Pseudomonas and Bacillus predominated in the conditions of monoculture . Many of the latter possessed weak catalase activity and drastically decreased the oxidation-reduction potential of the medium . Microbiol complexes in soddy-podzolic soil, when summer wheat was grown as a monoculture for a long period of time, were characterized by the following properties: most species were incapable of utilizing mineral nitrogen; the activity of proteolytic enzymes was low; the denitrifying activity was high.

Biochem J, 1980 Oct 15, 192(1), 231 - 40
The location of dissimilatory nitrite reductase and the control of dissimilatory nitrate reductase by oxygen in Paracoccus denitrificans; Alefounder PR et al.; 1 . A method is described for preparing spheroplasts from Paracoccus denitrificans that are substantially depleted of dissimilatory nitrate reductase (cytochrome cd) activity . Treatment of cells with lysozyme + EDTA together with a mild osmotic shock, followed by centrifugation, yielded a pellet of spheroplasts and a supernatant that contained d-type cytochrome . The spheroplasts were judged to have retained an intact plasma membrane on the basis that less than 1% of the activity of a cytoplasmic marker protein, malate dehydrogenase, was released from the spheroplasts . In addition to a low activity towards added nitrite, the suspension of spheroplasts accumulated the nitrite that was produced by respiratory chain-linked reduction of nitrate . It is concluded that nitrate reduction occurs at the periplasmic side of the plasma membrane irrespective of whether nitrite is generated by nitrate reduction or is added exogenously . 2 . Further evidence for the integrity of the spheroplasts was that nitrate reduction was inhibited by O2, and that chlorate was reduced at a markedly lower rate than nitrate . These data are taken as evidence for an intact plasma membrane because it was shown that cells acquire the capability to reduce nitrate under aerobic conditions after addition of low amounts of Triton X-100 which, with the same titre, also overcame the permeability barrier to chlorate reduction by intact cells . The close relationship between the appearance of chlorate reduction and the loss of the inhibitory effect of O2 on nitrate reduction also suggests that the later feature of nitrate respiration is due to a control on the accessibility of nitrate to its reductase rather than on the flow of electrons to nitrate reductase.

J Gen Microbiol, 1980 Oct, 120(Pt 2), 439 - 46
A study of the Va-1 group of pseudomonads and its relationship to Pseudomonas pickettii; Pickett MJ et al.; The Va-1 group of denitrifying pseudomonads was characterized and compared with Pseudomonas pickettii (Va-2) . They share many features but differ in their production of acid from cellobiose, lactose and maltose and in their denitrification (gas from nitrate) at 35 degrees C . DNA-DNA hybridizations between a strain of Va-1 and the type strain of P . pickettii disclosed 84% homology and hence indicated that Va-1 is a biovar of this species . Since both are potential human pathogens, features are presented that distinguish these and other phenotypically similar species that are recovered from clinical specimens.

Can J Biochem, 1980 Oct, 58(10), 996 - 1003
The use of bee venom melittin to assess the topography of membrane vesicles derived from Paracoccus denitrificans; Pik JR et al.; There exists considerable controversy regarding membrane topography in vesicles derived by osmotic lysis of spheroplasts of Gram-negative bacteria . It has been reported by others that bee venom can be used to quantitate the portion of a heterogeneous vesicle population with an inside-out orientation by determining the degree of loss of crypticity of NADH dehydrogenase activity . We have demonstrated that a major component of bee venom, melittin, causes an increase in the activity of several different respiratory enzymes in isolated membrane vesicles of Paracoccus denitrificans . The degree of stimulation produced by melittin is dependent upon (i) the nature of the respiratory substrates, (ii) the pH, (iii) the presence of Mg2+, (iv) the melittin: membrane protein ratio, and (v) the growth history of the cells from which the membrane vesicles were derived . Melittin-induced enhancement of TMPD:ascorbate and cytochrome c oxidase activities cannot be accounted for by increased accessibility of nonpermeant substrate to the interior of the vesicle . The stimulatory effect of melittin may rely in part on its ability to alter the proton permeability of the membrane thereby abolishing respiratory control . Collectively these observations call into question the usefulness of bee venom melittin in quantitative analyses of membrane topography . These results are consistent with the postulated existence of a homogeneous vesicle population in which the topography of the NADH dehydrogenase is different from that of the intact cell.

Biochim Biophys Acta, 1980 Sep 8, 619(3), 453 - 70
Studies on cyclopropane fatty acid synthesis . Effect of carbon source and oxygen tension on cyclopropane fatty acid synthetase activity in Pseudomonas denitrificans; Jacques NA et al.; The cyclopropane fatty acid, methylene hexadecanoic acid, constituted from 1% to upwards of 30% of the total lipid fatty acids of the bacterium, Pseudomonas denitrificans . The amount of this component varied along with the levels of the enzyme, cyclopropane synthetase (unsaturated-phospholipid methyltransferase, EC 2.1.1.16) . When P . denitrificans was grown on succinate in a culture medium saturated with oxygen, cyclopropane synthetase remained repressed while cell densities were low . As cell densities increased, the enzyme was induced and the activity rose to a maximum over a period of 4-6 h . Cyclopropane synthetase could also be induced by rapidly limiting the oxygen supply to cells growing in conditions where oxygen was in excess . This phenomenon was independent of the phase of growth and could be prevented by addition of chloramphenicol to the medium . Growth on glucose was also shown to repress the synthesis of cyclopropane synthetase under similar conditions . However, once maximum levels of cyclopropane synthetase were reached, they remained constant for at least the following 15 h irrespective of the source of carbon in the medium . Methylene hexadecanoic acid accumulated in a linear manner throughout this period until a maximum level was achieved, the rate of accumulation being related to the activity of cyclopropane synthetase detected in vitro . The rate of conversion of total fatty acid to methylene hexadecanoic acid was approximately 1.3-1.5% per h, the methylene hexadecanoic acid being metabolically stable - the relative percentage of methylene hexadecanoic acid to total fatty acid in repressed cells, falling linearly with increase in cell number . Repression of enzyme synthesis was further investigated by growing cells on various sources of carbon other than glucose . The results indicated that succinate was unique amongst tricarboxylic acid cycle intermediates in depressing cyclopropane synthetase under limited oxygen conditions.

Antimicrob Agents Chemother, 1980 Aug, 18(2), 249 - 56
Mode of action of copper complexes of some 2,2'-bipyridyl analogs on Paracoccus denitrificans; Smit H et al.; Copper complexes of 2,2'-bipyridyl and related compounds and CuSO4 inhibited the growth of paracoccus denitrificans . The copper(I) complex of 2,9-dimethyl-1,10-phenanthroline {Cu(DMP)2NO3} showed the highest activity, whereas the copper(II) complex of 1,10-phenanthroline and CuSO4 inhibited the growth to a lesser extent . The uncomplexed ligands (1,10-phenanthroline and 2,9-dimethyl-1,10-phenanthroline) showed little activity, but in the presence of noninhibitory amounts of CuSO4 this activity increased markedly . Copper ions therefore proved to be essential for the growth-inhibitor effect . The extent of inhibition appeared to be strongly dependent on the initial cell density and on the growth medium . No selective inhibition of deoxyribonucleic acid, ribonucleic acid, or protein synthesis was observed with Cu(DMP)2NO3 . Respiratory electron transport of P . denitrificans appeared to be strongly inhibited by Cu(DMP)2NO3 and to a somewhat lesser extent by CuSO4 . Both aerobic and anaerobic respirations were inhibited to the same extent, and from the cytochrome redox kinetics it is concluded that the site of this inhibition in the respiratory electron transport chain must be located before cytochrome b . Cu(DMP)2NO3 did not significantly influence the H+/O ratio with whole cells of P . denitrificans, suggesting that the efficiency of oxidative phosphorylation is not affected by CU(DMP)2NO3 . Growing cultures of P . denitrificans showed a decrease in intracellular potassium ion content in the presence of increasing amounts of Cu(DMP)2NO3 . It is concluded that interference with the cytoplasmic membrane, resulting in inhibition of respiratory electron transport, probably constitutes the main mode of action of copper complexes of 2,2'-bipyridyl analogs on P . denitrificans.

Ann Microbiol (Paris), 1980 Jul-Aug, 131B(1), 69 - 80
{Quantitative study of biological denitrification in soil with the aid of acetylene . I.--Application on different soils (author's transl)}; Germon JC; The use of acetylene for investigation about biological denitrification in soils requires study of intensity and persistence of N2O-reductase activity inhibition by this gas and the effects on the other stages of denitrification and on the general metabolism of microflora . The methodology used is described, taking into account N2O solubility . N2O-evolution rates from nitrite and nitrate were measured during long-term incubations under acetylene, and complete inhibition of N2O-reductase was observed . After 2 weeks, acetylene inhibition appears decreased . The nitrate reduction rate seems increased in the presence of acetylene.

Appl Environ Microbiol, 1980 Jul, 40(1), 108 - 13
Microbial activity of trench leachates from shallow-land, low-level radioactive waste disposal sites; Francis AJ et al.; Trench leachate samples collected anoxically from shallow-land, low-level radioactive waste disposal sites were analyzed for total aerobic and anaerobic populations, sulfate reducers, denitrifiers, and methanogens . Among the several aerobic and anaerobic bacteria isolated, only Bacillus sp., Pseudomonas sp., Citrobacter sp., and Clostridium sp . were identified . Mixed bacterial cultures isolated from the trench leachates were able to grow anaerobically in trench leachates, which indicates that the radionuclides and organic chemicals present were not toxic to these bacteria . Changes in concentrations of several of the organic constituents of the waste leachate samples were observed due to anaerobic microbial activity . Growth of a mixed culture of trench-water bacteria in media containing a mixture of radionuclides, 60Co, 85Sr, and 134,137Cs, was not affected at total activity concentrations of 2.6 X 10(2) and 2.7 X 10(3) pCi/ml.

Ann Microbiol (Paris), 1980 Jul-Aug, 131B(1), 81 - 90
{Quantitative study of biological denitrification in soils with the aid of acetylene . II.--Evolution of inhibitory effect of acetylene on N2O-reductase; influence of acetylene on denitrification rate and on nitrate immobilisation (author's transl)}; Germon JC; Study of kinetics of nitrate or nitrite disappearance in soils incubating with atmosphere with or without acetylene, shows that the presence of this gas increases the rate of nitrate or nitrite reduction, and therefore very probably the denitrification process . The decrease of inhibitory effect on N2O-reductase after incubation during 15 days appears to be due to a great extent at a biological transformation of this gas with a consecutive increase of CO2 production . On the other hand, acetylene does not seem to affect perceptibly nitrate immobilisation.

J Inorg Biochem, 1980 Jul, 12(4), 343 - 51
Reduction of DL-selenocystine and isolation of L-seleoncysteine; Burnell JN et al.; Cystine, selenocytsine, and several analogs were reduced by dithiothreitol (DTT), beta-mercaptoethanol (ME) and sodium borohydride (NaBH4) . DTT was the most effective; DTT to cystine ratios from 10 to 80 were equally effective . With selenocysteine, however, absorption was considerably reduced at all ratios . Selenocysteine was identified as the reduction product by reaction with Gaitonde's reagent, comparison of absorption spectra, paper chromatograhy, utilization by cysteinyl-tRNA synthetase fro Paracoccus denitrificans and Vigna radiata, changes in solubility after DTT treatment, and comparison of infrared spectra . During the ATP-PPi exchange assay, DTT and ME convert cysteine and selenocysteine derivatives to cysteine and selenocysteine which serve as substrates for cysteinyl-tRNA synthetase.

J Gen Microbiol, 1980 Jul, 119(1), 145 - 54
The orientation of cytochromes in membrane multilayers prepared from aerobically grown Escherichia coli K12; Poole RK et al.; Centrifugation of membrane vesicles, prepared from ultrasonically disrupted Escherichia coli K12, on to a planar surface followed by slow, partial dehydration results in a high degree of parallel orientation of the membrane planes with respect to each other and the supporting surface . Rotation of such membrane multilayers about a single axis parallel with the membrane planes within the magnetic field of an electron paramagnetic resonance (e.p.r.) spectrometer allows the orientation of anisotropic paramagnetic centres to be deduced . Computer simulations of the angular dependence of cytochrome e.p.r . spectra show two, or perhaps three, cytochromes, well-oriented with respect to the membrane plane . A low-spin cytochrome is oriented with the normal to its haem plane lying in the membrane plane . One (or perhaps two) high-spin cytochrome(s) lies with its haem plane making an angle of 45 degrees with the membrane plane . The orientation of the low-spin cytochrome haem is thus the same as that of haems in b-type cytochromes and cytochrome oxidases of the a type found in the mitochondria of higher animal and microbial cells and the bacterium Paracoccus denitrificans (Erecinska et al., 1979) . The possible identity of this low-spin component as the terminal oxidase, cytochrome o, is discussed.

J Biochem (Tokyo), 1980 Jul, 88(1), 223 - 30
Purification and properties of thiamine pyrophosphokinase in Paracoccus denitrificans; Sanemori H et al.; The existence of thiamine pyrophosphokinase {EC 2.7.6.2} in procaryotic cells was first demonstrated in Paracoccus denitrificans (J . Bacteriol, (1976) 126, 1030-1036) . The enzyme was therefore purified from this organism to determine its molecular structure and properties . Thiamine pyrophosphokinase which was purified 620-fold from P . denitrificans showed a single band on both polyacrylamide and sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis, and the molecular weight in the latter case was calculated to be 23,000 . Gel filtration analysis using Sephadex G-150 gave a molecular weight of 44,000, indicating that this enzyme contains at least two identical subunits . Although sedimentation equilibrium analysis gave a molecular weight of 96,000, indirect evidence suggests that the form having this molecular weight is an aggregate of the functional dimer . The activity of the purified enzyme required thiamine, ATP, and Mg2+, and the enzyme catalyzed thepyrophosphorylation of thiamine by ATP . Km values for thiamine and ATP were 10 microM and 0.38 mM, respectively . The activity was competitively inhibited by pyrithiamine, giving a Ki value of 19 microM . Oxythiamine and chloroethylthiamine were very weak inhibitors of the enzyme . The activity was also inhibited by the product, TPP.

J Biol Chem, 1980 Jun 10, 255(11), 5027 - 30
13N,15N isotope and kinetic evidence against hyponitrite as an intermediate in dentrification; Hollocher TC et al.; 13N- and 15N-labeling experiments were carried out with Paracoccus denitrificans, grown anaerobically on nitrate, to determine whether hyponitrite might be an obligatory intermediate in denitrification and a precursor of nitrous oxide . From experiments designed to trap {13N}- or {15N,15N}hyponitrite by dilution into authentic hyponitrite it was calculated that the intracellular concentration of a presumptive hyponitrite pool must be less than 0.4 mM . In order for a pool of this size to turn over rapidly enough to handle the flux of nitrogen during dentrifucation, the spontaneous rate of hyponitrite dehydration must be enhanced by a factor of several thousand through enzyme catalysis . Cell extracts failed to catalyze this reaction under a variety of conditions . It is concluded that hyponitrite cannot be an intermediate in dentrification . In addition, the assimilation of inorganic nitrogen was studied in P . denitrificans using 13N as tracer . At low concentrations (less than 10(-8) M) of labeled nitrate and nitrite 5 to 10% of the label was assimilated into non-volatile metabolites and 90 to 95% was reduced to N2 . Similarly, with 15 mM {13N}nitrate, 5% of the label went into metabolites and 95% to N2 . High pressure liquid chromatography analysis of the labeled metabolites indicated that the major pathway for assimilation of inorganic nitrogen in P . denitrificans under these conditions is through ammonia incorporation via the aspartase reaction.

Arch Microbiol, 1980 Jun, 126(2), 155 - 9
Effects of molybdenum and tungsten on induction of nitrate reductase and formate dehydrogenase in wild type and mutant Paracoccus denitrificans; Burke KA et al.; Molybdenum is required for induction of nitrate reductase and of NAD-linked formate dehydrogenase activities in suspensions of wild type Paracoccus denitrificans; tungsten prevents the development of these enzyme activities . The wild type forms a membrane protein Mr150,000 when incubated with tungsten and inducers of nitrate reductase and this is presumed to represent an inactive form of the enzyme . Suspensions of mutuant M-1 did not develop nitrate reductase or formate dehydrogenase activities but the membrane protein Mr150,000 was formed under all conditions tested, including without inducers and without molybdenum . Analysis of membranes, solubilized with deoxycholate, by polyacrylamide gel electrophoresis under nondenaturing conditions showed that the mutant protein had similar electrophoretic mobility to the active nitrate reductase formed by the wild type . Autoradiography of preparations from cells incubated with 55Fe showed that the mutant and wild type proteins contained iron . However, in similar experiments with 99Mo, incorporation of molybdenum into the mutant protein was not detectable . We conclude that mutant M-1 is defective in one or more steps required to process molybdenum for incorporation into molybdoenzymes . This failure affects the normal regulation of nitrate reductase protein with respect to the role of inducers.

Arch Microbiol, 1980 Jun, 126(2), 149 - 53
Induction of nitrate reductase and membrane cytochromes in wild type and chlorate-resistant Paracoccus denitrificans; Calder K et al.; An experimental system has been devised for induction of nitrate reductase in suspensions of wild type Paracoccus denitrificans incubated with limited aeration in the presence of azide, nitrate or nitrite . Azide promoted maximum synthesis of enzyme, accompanied by formation of excess b-type cytochrome; the level of enzyme attained with nitrate was less and c-type cytochrome predominated in the membrane . The nitrate reductase was solubilized with deoxycholate from membranes of azide-induced cells and was identified as a major polypeptide Mr = 150,000 by sodium dodecyl sulphate-polyacrylamide gel electrophoresis . Mutants strains lacking nitrate reductase activity were isolated on the basis of resistance to chlorate and mutant M-1 was examined in detail . When incubated in the cell suspension system M-1 formed a membrance protein Mr = 150,000 similar to that attributed to nitrate reductase in the wild type . Maximum formation of the protein by M-1 occurred without inducer and it was accompanied by synthesis of excess b-type cytochrome . The observations with wild type and M-1 indicate that nitrate reductase protein and b-type cytochrome are co-regulated and that the active enzyme has a role in regulating its own synthesis.

Mikrobiologiia, 1980 May-Jun, 49(3), 373 - 6
{Inhibition of the autotrophic growth of hydrogen bacteria by the autoregulation factor}; Savel'eva ND et al.; The purpose of this work was to study the action of the autoregulation factor isolated from the organotrophous culture of Pseudomonas carboxydoflava Z-1107 on autotrophous growth of this organism and some other cultures of hydrogen bacteria . If a sufficient dose of this metabolite was added to the culture growing lithoautotrophously, the growth of Ps . carboxydoflava Z-1107 stopped completely after 24 hours . A curve of false diauxia was observed if an increase in the concentration of the autoregulation factor in the culture was not great enough . When the factor acted on the autotrophously growing cultures of Alcaligenes eutrophus, Pseudomonas pantotropha and Paracoccus denitrificans, it was established that this endogenous metabolite possessed group specificity, and was capable of inhibiting, more or less, autotrophous growth of this hydrogen bacterium.

Antimicrob Agents Chemother, 1980 May, 17(5), 789 - 97
Antibiotic resistance in Neisseria denitrificans; MacKenzie CR et al.; An ampicillin-resistant strain of Neisseria denitrificans was produced by serial passage of the organisms in media containing increased concentrations of antibiotic . The 400-fold increase in resistance obtained was a relatively stable characteristic . Ampicillin resistance in this organism was apparently related to a loss or modification of the penicillin-binding proteins associated with the cytoplasmic membranes . Membranes isolated from the ampicillin-resistant strain bound significantly less radioactive penicillin than those isolated from the parent strain and revealed one major and three minor penicillin-binding proteins . All four penicillin-binding proteins were present in reduced amounts or had a decreased capacity for penicillin binding in the ampicillin-resistant cells . The increased resistance did not involve enzymic degradation of the antibiotic or a general reduction in the permeability of the outer layers of the cell . No difference in the amount of peptidoglycan present in the parent and ampicillin-resistant cells or in the gross chemical structure of the peptidoglycans of the two strains was observed.

Eur J Biochem, 1980 Apr, 105(2), 267 - 74
Isolation and characterization of an ornithine-containing lipid from Paracoccus denitrificans; Thiele OW et al.; The isolation and characterization of an ornithine-containing lipid from various strains of Paracoccus denitrificans (grown heteretrophically and autotrophically) is reported . The structure of this aminolipid was found to be H2N--CH2--(CH2)2--CH{NH--CO--CH2--CH(O--CO--R1)--R2}--CO2H, where R1 predominantly represents the residue of octadec-11-enoic acid, R2 the residue of a 3-hydroxyeicos-13-enoic acid . In addition, the major phospholipids (phosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol) were isolated and characterized.

Mikrobiologiia, 1980 Mar-Apr, 49(2), 284 - 7
{Nitrogen transformation as a result of Pseudomonas denitrificans denitrification}; Il'ina TK et al.; The energy process of nitrate reduction was studied in the typical soil denitrifying cultures of Pseudomonas denitrificans by mass spectrometry . These microorganisms differed in certain characteristics of the process from the cultures of sporogenic soil denitrifying bacteria belonging to the Bacillus genus . The rate of denitrification by Ps . denitrificans was very high; as the result, losses of 15N from the medium exceeded 80--90% . Ammonia was not produced as the final product of nitrate reduction in the course of denitrification . Apparently, hydroxylamine, hyponitrite or an organic intermediate product of nitrate reduction is produced in the process of its assimilation by the cultures.

Ann Microbiol (Paris), 1980 Mar-Apr, 131A(2), 197 - 207
{Distribution of heterotrophic aerobic microflora and specially denitrifying and free-living nitrogen-fixing bacteria in the rhizosphere of rice (author's transl)}; Roussos S et al.; The distribution of heterotrophic aerobic bacteria, actinomycetes and fungi was estimated in three samples (rhizospherical soil (SR), rhizoplane (R) and endorhizosphere (ER)) obtained from one rice seedling which had grown in pot during four mounths in a Casamance grey soil . The number of microbial populations were about the same from one sample to another: 1.1 to 2 X 10(8) bacteria, 3.3 to 8.6 X 10(6) actinomycetes and 0.2 to 8.9 X 10(4) fungi per gram of dry soil (SR) or dry roots (R and ER) . The denitrifying and free-living nitrogen fixing bacteria were numerous (10(7) bacteria/g) but lower for ER where the number of actinomycetes remained high . Thirty-six bacterial strains have been isolated from every sample with the use of a grid of isolation . The Gram-negative bacteria were dominant in SR and R where they represented respectively 70 and 94% of total count . The major groups were non-sporulated Gram-variable rods (SR) and Alcaligenes-like bacteria (ER) . The pseudomonads represented quite 15% of total count in the three samples . On the other hand, the frequency of endospore-forming Gram-positive bacteria was high only in R where the Bacillus group was estimated to 45% of total count . Only 5 free-living nitrogen-fixing bacterial strains had shown a denitrifying ability.

J Biol Chem, 1980 Jan 25, 255(2), 704 - 7
First practical assay for soluble nitrous oxide reductase of denitrifying bacteria and a partial kinetic characterization; Kristjansson JK et al.; Lysis of spheroplasts made from denitrification-adapted Paracoccus denitrificans released a soluble nitrous oxide reductase which was assayed spectrophotometrically under anaerobic conditions by following the oxidation of methyl or benzyl viologen cation radical upon reduction of N2O to N2 . Other classes of reductants so far tested, including dithionite, could not substitute for viologen dyes . Viologen dyes, therefore, afford the first practical assay for this previously elusive enzyme of denitrifying bacteria . The assay is specifically an in vitro assay, because the dyes cannot couple with intracellular nitrous oxide reductase . The enzyme exhibited simple saturation kinetics with respect to both N2O and reduced viologen dye . The Km for N2O was about 5 microM at 22 degrees C and pH 7.1 and the apparent Km for reduced benzyl and methyl viologen was 0.9 and 0.5 microM, respectively . Both dyes afforded the same Vmax value . Oxidized viologen dyes were not inhibiting to 1 mM nor was N2 to 1 atm . In fresh lysates, Vmax was about 1.2 mumol of N2O X min-1 x mg of protein-1 or about twice that for intact cells or spheroplasts utilizing yeast extract or lactate . Enzyme activity was observed to be labile in crude preparations under anaerobic conditions . Nitrous oxide reductase was inhibited by acetylene, CO, azide, and cyanide with Ki values of 28, 3.5, 0.35, and 0.045 microM, respectively . All showed noncompetitive inhibition with respect to N2O.

Ann Nutr Aliment, 1980, 34(5-6), 979 - 88
{Increase of nitrates in underground aquifers: study of a karstic basin in the Dijon area}; Simon JL et al.; The purpose of the study was to explain the enormous increase of nitrates in the waters of river Beze (Cote-d'Or) belonging to a well-defined karstic basin . This paper deals with surface and underground waters, pedologic formations and their rock base . It consisted in listing the oligoelements involved in the enzymic processes of nitrate reduction, the microflora and in determining the kinetics of denitrification by column perfusion . The presence of biodegradable carbon compounds is the governing factor of denitrification; their rapid lass related to new agricultural processes and the excessive use of nitrogene fertilizers are responsible for the enormous increase of nitrates observed.

Antonie Van Leeuwenhoek, 1980, 46(2), 143 - 55
The regulation of hydrogenase formation as a differentiating character of strains of Paracoccus denitrificans; Nokhal TH et al.; Paracoccus denitrificans strains Stanier 381 (DSM 65), Morris (DSM 413), and Vogt 11 (DSM 415) and eleven newly isolated strains were compared with respect to the localization of hydrogenase and its regulation . In all strains hydrogenase was found to be membrane-bound and not able to reduce pyridine nucleotides . The enzyme was inducible in strain 381 and was found only in cells grown with hydrogen as the sole hydrogen donor; in cells grown under mixotrophic or heterotrophic conditions the hydrogenase activity was zero . In all other strains hydrogenase was constitutive and was present in cells grown under autotrophic, mixotrophic and heterotrophic conditions . Under the latter conditions the specific hydrogenase activity was even higher than under mixotrophic conditions.

Appl Environ Microbiol, 1980 Jan, 39(1), 105 - 8
Inhibition by sulfide of nitric and nitrous oxide reduction by denitrifying Pseudomonas fluorescens; Sorensen J et al.; The influence of low redox potentials and H2S on NO and N2O reduction by resting cells of denitrifying Pseudomonas fluorescens was studied . Hydrogen sulfide and Ti(III) were added to achieve redox potentials near -200 mV . The control without reductant had a redox potential near +200 mV . Production of 13NO, {13N}N2O, and {13N}N2 from 13NO3- and 13NO2- was followed . Total gas production was similar for all three treatments . The accumulation of 13NO was most significant in the presence of sulfide . A parallel control with autoclaved cells indicated that the 13NO production was largely biological . The sulfide inhibition was more dramatic at the level of N2O reduction; {13N}N2O became the major product instead of {13N}N2, the dominant product when either no reductant or Ti(III) was present . The results indicate that the specific action of sulfide rather than the low redox potential caused a partial inhibition of NO reduction and a strong inhibition of N2O reduction in denitrifying cells.

Proc Natl Acad Sci U S A, 1980 Jan, 77(1), 196 - 200
A two-subunit cytochrome c oxidase (cytochrome aa3) from Paracoccus dentrificans; Ludwig B et al.; Cytochrome c oxidase (ferrocytochrome c: oxygen oxidoreductase, EC 1.9.3.1) was purified from the cytoplasmic membrane of the bacterium Paracoccus denitrificans . The enzyme contains two heme groups (a and a3) and two copper atoms per minimal unit, oxidizes mammalian cytochrome c at a high rate, and, when incorporated into liposomes, generates an electrochemical proton gradient during cytochrome c oxidation . Sodium dodecyl sulfate/polyacrylamide gel electrophoresis reveals only two subunits of apparent molecular weights 45,000 and 28,000; they appear to correspond to the two largest mitochondrially made subunits of the seven-subunit cytochrome c oxidase isolated from yeast mitochondria . Because of its structural simplicity . Paracoccus cytochrome c oxidase offers new possibilities for exploring the mechanism of cytochrome c oxidase function.

Biochim Biophys Acta, 1979 Dec 6, 548(3), 484 - 99
Reduction of nitrite to nitrous oxide by a cytoplasmic membrane fraction from the marine denitrifier Pseudomonas perfectomarinus; Zumft WG et al.; A cytoplasmic membrane fraction from the marine denitrifier Pseudomonas perfectomarinus reduced nitrite to nitrous oxide in a stoichiometric reaction without nitric oxide as free intermediate . The membrane system had a specific requirement for FMN with NAD(P)H as electron donors . Other electron donors were ascorbate-reduced cytochrome c-551 or phenazine methosulfate . The membrane fraction contained tightly bound cytochrome cd which represented only a small portion of the total cytochrome cd of the cell . As further terminal oxidase cytochrome o was identified . The membrane fraction produced also nitrous oxide from nitric oxide, however, at a substantially lower rate than from nitrite when using ascorbate-reduced phenazine methosulfate as electron donor.

Z Naturforsch {C}, 1979 Dec, 34(12), 1272 - 4
Distribution of thioredoxins in Cyanobacteria; Schmidt A et al.; The presence of thioredoxin was demonstrated in 20 strains of cyanobacteria as well as in one phototrophic bacterium Rhodopseudomonas sulfidophila and in Thiobacillus denitrificans . Thioredoxin activity was not found in Cyanophora paradoxa and in Porphyridium cruentum using the thioredoxin-dependent PAPS-sulfotransferase activity from Synechococcus 6301 as assay system.

Biochim Biophys Acta, 1979 Sep 12, 570(1), 43 - 55
Comparison of the membrane-bound and detergent-solubilised hydrogenase from paracoccus denitrificans . Isolation of the hydrogenase; Sim E et al.; The hydrogenase from Paracoccus denitrificans is an integral membrane protein and has been solubilised by Triton X-100 . The membrane-bound and detergent-solubilised forms of the enzyme have been compared . Both forms of the enzyme show a pH optimum for reduction of benzyl viologen at pH 8.5--9.0 and are both inhibited by concentrations of NaCl greater than 30 mM . An Arrhenius plot of the activity of hydrogenase in the membrane shows no 'break' . The form of the Arrhenius plot and the activation energy are not significantly changed on solubilisation of the enzyme . The Km and V values for benzyl viologen, methyl viologen and H2 are unaltered when the enzyme is extracted from the membrane . Therefore, solubilisation of hydrogenase from the membrane by Triton X-400 is unlikely to disrupt the native conformation of the enzyme . The detergent-solubilised hydrogenase has subsequently been purified using ammonium sulphate precipitation, sucrose density gradient centrifugation and chromatography on hydroxyapatite . The overall yield of activity is 23%, with a final purification of over 100-fold.

Biochemistry, 1979 Sep 4, 18(18), 3921 - 6
Implications of the integrated rate law for the reactions of Paracoccus denitrificans nitrite reductase; Robinson MK et al.; The integrated rate law for the reaction of the nitrite reductase of Paracoccus denitrificans, a cytochrome cd, has been established for turnover assays using donor ferrocytochromes c and either nitrite or molecular oxygen as the ultimate acceptor . The time course for the concentration of ferrocytochrome follows the law: formula: (see text), where S is the concentration of donor ferrocytochrome c, So is the initial concentration, t is time, and u1, u2, and u3 are empirical parameters that are constant for a given experiment but depend upon the initial substrate concentration . In particular, all the u1 increase with decreasing initial ferrocytochrome concentration . Saturation of reaction rates at high donor ferrocytochrome concentrations was not observed . The parameter u1 was proportional to the enzyme concentration while u2 and u3 were not . The form of the integrated rate law and the behavior of the u1 impose severe restrictions on possible kinetic schemes for the activity of the enzyme . Contemporary mechanisms that have been proposed for mitochondrial oxidase aa3 are examined and found to be inadequate to explain the reactivity of cytochrome cd . The simplest interpretations of the cytochrome cd data suggest that the enzyme does not bind the ferri and ferro forms of donor cytochromes c with equal affinity and that the enzyme is subject to inhibition by a product of reaction . Eucaryotic horse cytochrome c reacts with the Paracoccus cytochrome cd with 77% of the activity when Paracoccus cytochrome c550 is used as the electron donor.

J Bacteriol, 1979 Sep, 139(3), 1062 - 4
Transfer of kanamycin resistance mediated by plasmid R68.45 in Paracoccus denitrificans; Paraskeva C; Plasmid R68.45 mediates the transfer of kanamycin resistance from Pseudomonas aeruginosa to Paracoccus denitrificans . Kanamycin resistance could be transferred from one strain of P . denitrificans to another, thus opening up the possibility of using R68.45 as a sex factor in P . denitrificans.

Biochem J, 1979 Sep 1, 181(3), 517 - 24
Structural aspects of the dye-linked alcohol dehydrogenase of Rhodopseudomonas acidophila; Bamforth CW et al.; 1 . A dye-linked alcohol dehydrogenase was purified 60-fold from extracts of Rhodopseudomonas acidophila 10050 grown aerobically on ethanol . 2 . The properties of this enzyme were identical with those of the alcohol dehydrogenase synthesized by this organism during growth on methanol anaerobically in the light, and they are judged to be the same enzyme . 3 . The enzyme gave a single protein band, coincident with alcohol dehydrogenase activity, during electrophoresis on polyacrylamide gel . 4 . The amino acid composition, ioselectric point, u.v . and visible absorption spectra of the enzyme were determined and compared with those of other similar enzymes . 5 . The presence of 0.7--1.0 g-atom of non-haem, acidlabile iron/mol of enzyme was shown by atomic absorption spectrophotometry and colorimetric assay . The iron could not be dissociated from the enzyme by dialysis against chelating agents . 6 . E.p.r . spectroscopy of the enzyme did not indicate any redox function for the iron during alcohol dehydrogenation, but showed a signal at g = 2.00 consistent with the presence of a protein-bound organic free radical . 8 . Antisera were raised against alcohol (methanol) dehydrogenases purified from Rhodopseudomonas acidophila, Paracoccus denitrificans and Methylophilus methylotrophus . 9 . The antiserum to the Rhodopseudomonas acidophila enzyme cross-reacted with neither of the two other antisera, nor with crude extracts of methanol-grown Hyphomicrobium X and Pseudomonas AM1, thus emphasizing its singular biochemical properties.

Arch Microbiol, 1979 Sep, 122(3), 263 - 70
Isolation and analysis of mutants of Pseudomonas aeruginosa unable to assimilate nitrate; Sias SR et al.; Pseudomonas aeruginosa can reduce nitrate to nitrite and evenutally to nitrogen gas by the denitrification pathway, thereby providing the organism with a mode of respiration and ATP generation in the absence of oxygen . P . aeruginosa can also reduce nitrate to nitrite through an assimilatory pathway that provides the cell with reduced nitrogen for biosyntheses . In order to establish whether this organism synthesizes a single nitrate reductase protein that functions in both pathways, or produces one for each pathway, we isolated mutants blocked in the assimilation of nitrate . These mutants are unaffected in the reduction of nitrate be the denitrification pathway, although they produce low or undectable levels of assimilatory nitrate reductase . On the basis of transductional analysis, the mutations were found to be distributed among four genes designated nasA, nasB, nasC, and nasD . Shifting a nasA mutant from anaerobic to aerobic growth eliminated the culture's ability to reduce nitrate, i.e . the anaerobic nitrate reductase cannot function in the presence of oxygen . Thus P . aeruginosa can synthesize two distinct proteins which reduce nitrate to nitrite: an assimilatory nitrate reductase and a dissimilatory nitrate reductase . If conditions of growth are fully aerobic, the latter is not synthesized and does not function . The former, synthesized under the control of at least four genes, is repressed by readily available nitrogen sources.

Biochem J, 1979 Jul 1, 181(1), 159 - 69
Isolation and properties of cytochrome c peroxidase from Pseudomonas denitrificans; Coulson AF et al.; The isolation of cytochrome c peroxidase, cytochrome c4, cytochrome c-551 and azurin from Pseudomonas dentrificans is described . The peroxidase has a molecular weight of 63,000 and an isoelectric point of 5.6 . Its absorption spectrum suggests that it contains two haem c groups/molecule . Preliminary steady-state kinetic data are reported with cytochromes c-551 and c4 and azurin as the second substrate.

Can J Microbiol, 1979 Jul, 25(7), 798 - 802
The effect of phenazine methosulfate-ascorbate on bacterial active transport and adenosine triphosphate formation: inhibition of Pseudomonas aeruginosa and stimulation of Escherichia coli; Eagon RG et al.; The artificial electron-donor system, phenazine methosulfate (PMS) ascorbate, inhibited active transport of glucose by Pseudomonas aeruginosa irrespective of whether the incubation systems were in air, flushed with oxygen, or gassed with nitrogen under anaerobic denitrifying conditions . Active transport of glucose by P . aeruginosa was also inhibited by reduced 5-N-methyl-phenazonium-3-sulfonate, a membrane-impermeable electron donor . PMS-ascorbate caused rapid depletion of intracellular adenosine triphosphate (ATP) when added to respiring cell suspensions of P . aeruginosa either in the presence or absence of glucose or succinate as oxidizable energy sources . In contrast, under identical conditions, Escherichia coli formed ATP with PMS-ascorbate as the sole oxidizable energy source and ATP formation continued when glucose or succinate was present in addition to PMS-ascorbate in the incubation system.

Biol Bull Acad Sci USSR, 1979 Jul-Aug, 6(4), 450 - 9
Loss of nitrogen by denitrification; Smirnov PM et al.; A series of experiments showed the quantity and composition of nitrogen lost in gaseous form from fertilizers in soil is largely determined by the conditions of denitrification . Loss of nitrogen from ammonium sulfate or calcium nitrate was mainly through the release of nitrous oxide and molecular nitrogen, while nitrogen was released from sodium nitrite in the form of nitric oxide . Under anaerobic conditions and at neutral soil pH in the presence of glucose, the more reduced gaseous forms of nitrogen were released . However, the oxides of nitrogen predominated under conditions unfavorable for denitrification . The nitrogen oxides were not the terminal products of nitrogen conversion (nitrates and nitrites) . By a process of dissimilation, the nitrogen oxides acted as electron acceptors for microorganisms, being converted to N2O and N2 . The reduction of NO generally led to the formation of N2O as an intermediate, and depended on pH, aeration, and the presence of an energy source for the denitrifying organisms.

Biochim Biophys Acta, 1979 Jun 6, 568(2), 454 - 66
Purification of Thiobacillus denitrificans siroheme sulfite reductase and investigation of some molecular and catalytic properties; Schedel M et al.; A siroheme-containing sulfite reductase was isolated from Thiobacillus denitrificans, purified to an electrophoretically homogenous state, and investigated with regard to some of its molecular and catalytic properties . The enzyme was a tetramer with a molecular weight of 160 000, consisting of two types of subunits arranged to an alpha 2 beta 2-structure . The molecular weight of the alpha-subunit was 38 000, that of the beta-subunit 43 000 . As prosthetic groups siroheme and Fe/S groupings could be detected . The absorption spectrum showed maxima at 273 nm, 393 nm, and 594 nm; the molar extinction coefficient at these wavelengths were 280, 181, and 60 . 10(3) cm2 . mmol-1, respectively . With reduced viologen dyes the enzyme reduced sulfite to sulfide, thiosulfate and trithionate . In many properties T . denitrificans sulfite reductase closely resembled desulfoviridin, the dissimilatory sulfite reductase of Dssulfovibrio species . It is proposed that the physiological function of this enzyme is not to reduce but rather to form sulfite from reduced sulfur compounds in the course of dissimilatory sulfur oxidation in T . denitrificans.

Eur J Biochem, 1979 Jun, 97(1), 119 - 26
Hydrodynamic parameters of the detergent-solubilised hydrogenase from Paracoccus denitrificans; Sim E et al.; The hydrogenase from Paracoccus denitrificans, which is an intrinsic membrane protein, has been solubilised from membranes by Triton X-100 . The partial specific volume of the solubilised protein has been determined using sucrose density gradient centrifugation in H2O and 2H2O . The values of the specific volumes of hydrogenase, measured in the presence or absence of Triton X-100, are 0.73 and 0.74 ml . g-1, respectively, indicating that hydrogenase binds much less than one micelle of Triton X-100 . The sedimentation coefficient of hydrogenase is increased from 10.4 S to 15.9 S on removal of detergent . The Stokes' radius of hydrogenase, determined by gel filtration on Sepharose 6B, is 5.5 nm in the presence of Triton X-100 compared to 6.7 nm in the absence of detergent . The apparent molecular weight therefore increases from 242,500 to 466,000 on removal of detergent . In the presence of urea and sodium dodecylsulphate, the hydrogenase has an apparent molecular weight of 63,000 . The enzyme therefore behaves as a non-covalently linked tetramer in the presence of Triton X-100 . Removal of Triton X-100 results in association of tetramers to form octamers.

Eur J Biochem, 1979 May 2, 96(1), 69 - 76
Anaerobic respiration and energy conservation in Paracoccus denitrificans . Functioning of iron-sulfur centers and the uncoupling effect of nitrite; Meijer EM et al.; 1 . Electron paramagnetic resonance spectra at 8-60 K of NADH-reduced membrane particles prepared from Paracoccus denitrificans grown anaerobically with nitrate as terminal electron acceptor show the presence of iron-sulfur centers 1-4 in the NADH-ubiquinone segment of the respiratory chain . In addition resonance lines at g = 2.058, g = 1.953 and g = 1.88 are detectable in the spectra of succinate-reduced membranes at 15 K, which are attributed to the iron-sulfur-containing nitrate reductase . 2 . Sulphate-limited growth under anaerobic conditions does not affect the iron-sulfur pattern of NADH dehydrogenase or nitrate reductase . Furthermore respiratory chain-linked electron transport and its inhibition by rotenone are not influenced . These results contrast those observed for sulphate-limited growth of P . denitrificans under aerobic conditions {Eur . J . Biochem . (1977) 81, 267-275} . 3 . Proton translocation studies of whole cells indicate that nitrite increases the proton conductance of the cytoplasmic membrane, resulting in a collapse of the proton gradient across the membrane . Nitrite accumulates under anaerobic growth conditions with nitrate as terminal electron acceptor; the extent of accumulation depends on the specific growth conditions . Thus the low efficiencies of respiratory chain-linked energy conservation observed during nitrate respiration {Arch . Microbiol . (1977) 112, 17-23} can be explained by the uncoupling action of nitrite.

Z Naturforsch {C}, 1979 May-Jun, 34C(5-6), 346 - 9
Improved synthesis and rapid isolation millimole quantities of adenylysulfate; Cooper BP et al.; An improved enzymatic method for the synthesis of adenylysulfate (APS) from adenosine 5'-phosphate using APS-reductase from Thiobacillus denitrificans is described . Isolation of millimole quantitities of this sulfur nucleotide is achieved rapidly by means of ion exchange chromatography on a strongly basic ion exchange resin . A facile and reproducible desalting procedure is described.

Biochem J, 1979 Apr 15, 180(1), 69 - 73
Interaction of lipophilic quinones with membrane fragments of Paracoccus denitrificans and Staphylococcus epidermidis; Mikes V et al.; In quinone-depleted mitochondrial and Paracoccus denitrificans membranes the quantum yield of fluorescence of ostruthin (6-geranyl-7-hydroxycoumarin) was maintained, whereas an increase in the quantum yield took place after extraction of Staphylococcus epidermidis membrane . A marked quenching effect of ubiquinone and menaquinone each with two isoprene units in the side chain on the ostruthin fluorescence was found with all types of quinone-depleted particles . When the homogues of menaquinone and ubiquinone with six isoprene units in the side chain were re-incorporated, a quenching of the ostruthin fluorescence was observed in the S . epidermidis membranes but not in those of P . denitrificans . The different behaviour of both bacterial preparations is attributable to the more specific finding of ubiquinone in the particles of P . denitrificans.

J Bacteriol, 1979 Mar, 137(3), 1227 - 33
Substrate binding site for nitrate reductase of Escherichia coli is on the inner aspect of the membrane; Kristjansson JK et al.; Escherichia coli grown anaerobically on nitrate exhibited the same transport barrier to reduction of chlorate, relative to nitrate, as that exhibited by Paracoccus denitrificans . This establishes that the nitrate binding site of nitrate reductase (EC 1.7.99.4) in E . coli must also lie on the cell side of the nitrate transporter which is associated with the plasma membrane . Because nitrate reductase is membrane bound, the nitrate binding site is thus located on the inner aspect of the membrane . Nitrate pulse studies on E . coli in the absence of valinomycin showed a small transient alkalinization (leads to H+/NO3- congruent to --0.07) which did not occur with oxygen pulses . By analogy with P . denitrificans, the alkaline transient is interpreted to arise from proton-linked nitrate uptake which is closely followed by nitrite efflux . The result is consistent with internal reduction of nitrate, whereas external reduction would be expected to give leads to H+/NO3-ratios approaching --2.

Biochim Biophys Acta, 1979 Feb 8, 545(2), 352 - 64
Studies of the orientation of the mitochondrial redox carriers . III . Orientation of the gx and gy axes of the hemes of cytochrome oxidase with respect to the plane of the membrane in oriented membrane multilayers; Erecinska M et al.; The EPR absorption properties of the hemes of cytochrome oxidase and their liganded derivatives were examined in oriented multilayers from isolated oxidase, mitochondrial membranes and membrane fragments of a bacterium, Paracoccus denitrificans . The hemes of the oxidase in all the systems investigated were oriented normal to the plane of the multilayers . The directions of the g signals corresponding to the gx and gy axes of the g tensor were found to be different in low-spin ferric heme in fully oxidized oxidase and in half-reduced liganded oxidase . It is suggested that this different orientation of gx and gy in fully oxidized oxidase and half-reduced liganded oxidase arises because the respective EPR signals belong to two different hemes, those of cytochrome a and a3.

Antonie Van Leeuwenhoek, 1979, 45(2), 225 - 40
Characterization and classification of fluorescent pseudomonads isolated from tap water and surface water; van der Kooij D; A total of 665 fluorescent pseudomonads, isolated from surface water and from different types of tap water, were classified into 22 groups defined by the results of the following 5 tests: hydrolysis of casein or gelatin, production of N2 from NO3-, and growth on sucrose, ethanol and D-sorbitol, respectively . Differences in colonial morphology and in the degree of proteolysis revealed that these groups were inhomogeneous . A more detailed subdivision was achieved by adding the following characters: growth on L-arabinose, D-mannitol, mesoinositol, and adonitol, respectively, and hydrolysis of Tween-80 . Repeating the tests for hydrolyzing enzymes, denitrification, and growth on the carbohydrates and alcohols with strains stored in the laboratory for 1 to 3 years revealed that most characters, except hydrolysis of Tween-80, denitrification, and growth on sucrose, were very stable . Forty-five biotypes of the fluorescent pseudomonads were defined, based on the results of the repeated tests and the results of tests on nine aromatic compounds . The observed changes of some characters in a number of isolates did not diminish the value of this classification, but indicated that close relationships exist between many biotypes . About half of the biotypes described in this paper are similar to those defined by Stanier, Palleroni and Doudoroff (1966) and by Doudoroff and Palleroni (1974a), confirming the wide-spread occurrence of well-definable biotypes of fluorescent pseudomonads . Representatives of some biotypes were most frequently isolated from surface water and from tap water prepared from surface water . Tap water prepared from anaerobic or aerobic ground water contained representatives of biotypes which were typical of these water types . Some pseudomonads were found to grow especially in filters . The observed relationships between origin of the fluorescent pseudomonads and their classification into biotypes as defined in this paper supported the presented classification.

Antonie Van Leeuwenhoek, 1979, 45(2), 185 - 97
Structural analysis of four strains of Paracoccus denitrificans; Nokhal TH et al.; Two out of eleven newly isolated strains of Paracoccus denitrificans were investigated by light and electron microscopic methods and compared with two strains of P . denitrificans already kept in culture collections . Samples were taken from different growth phases revealing short rods and nearly spherical cells in the exponential growth phase, and an increasing ratio of nearly spherical cells in the stationary growth phase . Cell division followed the binary fission mode; higher cell aggregates were not observed . Fine structural analysis revealed extracellular surface material stainable with Ruthenium red, a gram-negative cell wall and different storage material inclusions . Structural properties and variations within the four strains under investigation are discussed and compared with those of related bacteria.

Zentralbl Bakteriol Naturwiss, 1979, 134(3), 217 - 22
Effect of organic matter supplementation on nitrogen transformations in soils . II . Nitrogen balance and yield; Abd-el-Malek Y et al.; Under controlled laboratory conditions, the effect of the application of uncomposted plant materials (sawdust and maize stalks) or horns and hooves (narrow C/N ratio) on soil nitrogen and plant growth was investigated . From nitrogen balance calculations it was found that the addition of the wide C/N ratio materials alone either increased soil nitrogen through N2-fixation or lessened nitrogen loss through denitrification . Although such materials resulted in the immobilisation of mineral nitrogen, no nitrogen starvation symptoms were noted on the growing plants . Negative nitrogen balances were usually obtained when soils received mineral nitrogen fertilizers either alone or together with maize stalks or supplemented with the narrow C/N ratio organic material.

Appl Environ Microbiol, 1978 Dec, 36(6), 809 - 13
Occurrence of nitric and nitrous oxides in a coastal marine sediment; Sorensen J; The distribution of denitrification activity in a coastal marine sediment was determined by the acetylene inhibition technique and compared to concentration profiles of NO3-, NO2-, NO, and N2O . The bulk of the denitrification activity was associated with the accumulation of NO3- in the oxidized surface zone of the sediment, but a secondary denitrification zone was occasionally found in the deeper layers where oxidized patches had been introduced by the burrowing activity of the macrofauna . Maxima of NO and N2O were not associated with the peak activity of denitrification in the surface zone but were located at the lower edge of the activity profile . Significant accumulation of NO was found at the redox transition zone towards the deeper, sulfide-rich layers.

Mikrobiologiia, 1978 Nov-Dec, 47(6), 1112 - 4
{Sequence of formation of gaseous products during anaerobic decomposition of cellulose in the presence of several electron acceptors}; Bonch-Osmolovskaia EA; The course of anaerobic cellulose decomposition by a mixed microbial association was studied in the presence of nitrate and sulfate ions in the medium . The succession of reductive processes was evaluated by the formation of gaseous products, i . e . nitrogen, hydrogen sulfide, and methane . The sequence of processes in the course of cellulose degradation was determined by the energy yield of oxidative-reductive reactions . Sulfate reduction predominated if lactate was assimilated by the same microbial association, while denitrification prevailed when the association used acetate.

Can J Microbiol, 1978 Nov, 24(11), 1395 - 403
Effect of oxygen and nitrate on nitrogen fixation and denitrification by Azospirillum brasilense grown in continuous culture; Nelson LM et al.; Azospirillum brasilense was grown continuously at various levels of dissolved oxygen (O2) in a nitrogen-free medium containing malates as the carbon source . Steady-state cultures were established only at O2 concentrations less than 0.0150 atm (1 atm = 101.325 Pa) and rates of acetylene reduction (N2 fixation) and efficiencies of N2 fixation were maximal between 0.0050-0.0075 atm dissolved O2 . These cultures appeared to be O2- or N2-limited . There was no evidence of a respiratory protective mechanism in this organism . Anaerobic denitrifying steady-state cultures were established with nitrate (NO3-) as the sole nitrogen source with no detectable N2 fixation . N2 fixation, but no denitrification, was observed when NO3- was decreased to 10 microgram N per millilitre at 0.003 atm dissolved O2 . In samples removed from the culture vessel, either activity could be induced with a lag of approximately 120 min by incubation under appropriate conditions.

Mikrobiologiia, 1978 Nov-Dec, 47(6), 1020 - 4
{Electrophoretic differences in the proteins of the species Pseudomonas aeruginosa and Pseudomonas denitrificans capable of oxidizing n-alkanes}; Illarionov EF et al.; Pseudomonas aeruginosa and Ps . denitrificans are capable of growing on n-alkanes, but differ in assimilation of higher and lower alkanes . The proteins of their cell-free homogenates were analysed by disc-electrophoresis in a system containing SDS . The "preliminarily adapted" strain of Ps . aeruginosa did not differ from the "non-adapted" to n-hexane strain, though both differed considerably from Ps . denitrificans in the composition of protein spectrum . Therefore, disc-electrophoresis of total proteins has shown that Ps . aeruginosa and Ps . denitrificans are not genetically identical; they exhibit certain common physiological properties, but apparently oxidize n-alkanes via different pathways.

Arch Microbiol, 1978 Oct 4, 119(1), 91 - 7
Aerobic and anaerobic growth of Paracoccus denitrificans on methanol; Bamforth CW et al.; 1 . The dye-linked methanol dehydrogenase from Paracoccus denitrificans grown aerobically on methanol has been purified and its properties compared with similar enzymes from other bacteria . It was shown to be specific and to have high affinity for primary alcohols and formaldehyde as substrate, ammonia was the best activator and the enzyme could be linked to reduction of phenazine methosulphate . 2 . Paracoccus denitrificans could be grown anaerobically on methanol, using nitrate or nitrite as electron acceptor . The methanol dehydrogenase synthesized under these conditions could not be differentiated from the aerobically-synthesized enzyme . 3 . Activities of methanol dehydrogenase, formaldehyde dehydrogenase, formate dehydrogenase, nitrate reductase and nitrite reductase were measured under aerobic and anaerobic growth conditions . 4 . Difference spectra of reduced and oxidized cytochromes in membrane and supernatant fractions of methanol-grown P . denitrificans were measured . 5 . From the results of the spectral and enzymatic analyses it has been suggested that anaerobic growth on methanol/nitrate is made possible by reduction of nitrate to nitrite using electrons derived from the pyridine nucleotide-linked dehydrogenations of formaldehyde and formate, the nitrite so produced then functioning as electron acceptor for methanol dehydrogenase via cytochrome c and nitrite reductase.

Biotechnol Bioeng . 1978 Oct;20(10):1667.
Dissimilatory nitrate reduction by liquid membrane encapsulated cell-free extracts and whole cells of Micrococcus denitrificans; Markovits A; The combination of Sephadex G-15 and ion-exchange resin columns allows one-step desalting and separation of cellodextrins using water as the sole eluent . The column apparatus described in this paper has the potential of producing up to 3 g cellodextrins in one day . In addition, the columns described are stable and do not require repacking or regeneration after each run . Hence the potential exists for scaling up this system for even greater production of cellodextrins if need be.

Appl Environ Microbiol, 1978 Aug, 36(2), 257 - 63
Denitrifying Pseudomonas aeruginosa: some parameters of growth and active transport; Williams DR et al.; Optimal cell yield of Pseudomonas aeruginosa grown under denitrifying conditions was obtained with 100 mM nitrate as the terminal electron acceptor, irrespective of the medium used . Nitrite as the terminal electron acceptor supported poor denitrifying growth when concentrations of less than 15 mM, but not higher, were used, apparently owing to toxicity exerted by nitrite . Nitrite accumulated in the medium during early exponential phase when nitrate was the terminal electron acceptor and then decreased to extinction before midexponential phase . The maximal rate of glucose and gluconate transport was supported by 1 mM nitrate or nitrite as the terminal electron acceptor under anaerobic conditions . The transport rate was greater with nitrate than with nitrite as the terminal electron acceptor, but the greatest transport rate was observed under aerobic conditions with oxygen as the terminal electron acceptor . When P . aeruginosa was inoculated into a denitrifying environment, nitrate reductase was detected after 3 h of incubation, nitrite reductase was detected after another 4 h of incubation, and maximal nitrate and nitrite reductase activities peaked together during midexponential phase . The latter coincided with maximal glucose transport activity.

Mikrobiologiia, 1978 Jul-Aug, 47(4), 611 - 6
{Effect of inorganic electron acceptors on the bacterial formation of methane from cellulose}; Bonch-Osmolovskaia EA et al.; The effect of nitrate, nitrogen oxide, sulphate, oxidized iron and manganese on the methane fermentation of cellulose was studied with the enrichment bacterial culture . The action of these oxidants on the enrichment culture growing on cellulose was compared to that on a pure methanosarcina culture in order to find out which stage of methane formation from cellulose was inhibited . Nitrate at the concentration of 2 g NaNO3 and more per litre of the medium inhibited the whole process of fermentation; at the concentration less than 2 g/l the production of methane was inhibited, and cellulose decomposition was accompanied with denitrification . Sulphate at the concentration of 2 g MgSO4 per litre had no effect on the formation of methane but the process was inhibited by the product of its reduction, i . e . sulphiade . Cellulose decomposition could be accompanied with sulphate reduction if sulphide produced in the process of the reduction were removed from the medium . In this case as well as in the presence of ferric iron, the production of methane was inhibited due to competition for the reducing agent.

Int J Radiat Biol Relat Stud Phys Chem Med, 1978 Jul, 34(1), 67 - 72
Irradiation of micro-organisms with mono-energetic X-rays; biological consequences of the Auger effect; Halpern A et al.; The radiation resonance effect reported previously for isolated biomolecules has now for the first time been observed in a cellular system . Dried bacteria, Micrococcus denitrificans, in which TdR in DNA was partially substituted by BUdR, were subjected to mono-energetic X-rays of energies below or above the K-edge for Br . Subsequently, the colony-forming ability was assayed . For photon energy slightly above the K-edge, the lethality/rad was greater than that below the K-edge . This is interpreted in terms of the Auger effect initiated selectively by photo-absorption in constituent Br atoms . The differential absorption of low-energy photons in constituent atoms of DNA is also discussed.

Can J Microbiol, 1978 Jun, 24(6), 757 - 60
Denitrification in Rhizobium; Zablotowicz RM et al.; Thirty-three strains of Rhizobium were examined for their reduction of nitrate under anoxic conditions . Three patterns of dissimilatory nitrate reduction were observed: (1) reduction to N2O and N2 (denitrification), (2) reduction to and subsequent accumulation of NO2- (nitrate respiration), (3) no reduction . Strains of R . japonicum and the cowpea miscellany displayed all three types, while strains of R . leguminosarum, R . phaseoli, and R . trifolii did not reduce nitrate by dissimilatory means . The production and subsequent metabolism of N2O was considerably different among the denitrifying strains: in some instances, N2O was a transient intermediate, while in others, it continued to accumulate during the incubation period.

J Bacteriol, 1978 Jun, 134(3), 1123 - 32
Ribulose bisphosphate carboxylase from methanol-grown Paracoccus denitrificans; Shively JM et al.; Paracoccus denitrificans grows on methanol as the sole source of energy and carbon, which it assimilates aerobically via the reductive pentose phosphate cycle . This gram-negative bacterium grew rapidly on 50 mM methanol (generation time, 7 h, 30 degrees C) in excellent yield (3 g of wet-packed cells per liter of culture) . Electron microscopic studies indicated that the late-log-phase cells were coccoid, having a thick envelope surrounding a layer of more diffuse electron-dense material and a relatively electron-transparent core . Ribulose bisphosphate carboxylase in the 15,000 X g supernatant of fresh cells had specific activities (micromoles of CO2 fixed per minute per milligram of protein) of 0.026, 0.049, 0.085, 0.128, and 0.034 during the lag, early, mild-, and late log, and late stationary phases, respectively . The enzyme was purified 40-fold by pelleting at 159,000 X g, salting out, sedimentation into a 0.2 to 0.8 M linear sucrose gradient, and elution from a diethylaminoethyl-Sephadex column . The enzyme was homogeneous by the criteria of electrophoresis on polyacrylamide gels polymerized from several acrylamide concentrations and sedimentation behavior . The molecular weight of the native enzyme, as measured by gel electrophoresis and gel filtration, averaged 525,000 . Sodium dodecyl sulfate dissociated the enzyme into two types of subunits with molecular weights of 55,000 and 13,600 . The S20,w of the enzyme was 14.0 Km values for ribulose bisphosphate and CO2 were 0.166 and 0.051 mM, respectively, and the enzyme was inhibited to the extent of 94% by 1 mM 6-phosphogluconate.

Can J Microbiol, 1978 May, 24(5), 608 - 17
{Morphological, physiological and taxonomic studies of Bacillus azotoformans}; Pichinoty F et al.; Seventeen strains of the new species Bacillus azotoformans were isolated by enrichment culture in peptone broth inoculated with pasteurized soil and then incubated under N2O at 32 degrees C . The bacterium is a Gram-negative rod, motile with peritrichous flagella, which produces oval spores without exosporia in swollen sporangia . However, the cells have thick walls, mesosomes, and persistent septa characteristic of Gram-positive bacteria . The bacterium lacks fermentative activity, does not attack carbohydrates, has complex growth requirements, and will grow anaerobically only if one of the following electron acceptors is present: NO3-, NO2-, N2O, S4O6--, or fumarate . Nitrate, nitrite, and nitrous oxide are denitrified with the production of N2 . The microorganism is mesophilic, gives a positive oxidase reaction, synthesizes a type c cytochrome, and does not hydrolyse gelatin, starch, or "Tween 80." Poly-beta-hydroxybutyric acid is snythesized when the bacterium is grown in a medium containing DL-3-hydroxybutyrate . The following enzymes are present: nitrate reductase A, respiratory nitrite reductase, tetrathionate and fumarate reductases, and L-glutamate dehydrogenase . The following enzymes are absent: thiosulfate reductase, urease, lecithinase, arginine dihydrolase, phenylalanine deaminase, and catalase . For the 17 strains, the mean value of the G = C percent of the DNA is 39.8 +/- 1.2 . All the strains are highly similar.

Can J Microbiol, 1978 May, 24(5), 569 - 73
Surcrose uptake by Neisseria denitrificans; MacKenzie CR et al.; Neisseria dentrificans possesses an inducible sucrose-uptake system . Sucrose is transported as the free sugar and is rapidly converted into polymerized material . Uptake is inhibited by glucose, cyanide, uncouplers of oxidative phosphorylation, and sulfydryl reagents . Glutamate serves as an energy source for uptake . The importance of this phenomenon in the oral environment is discussed.

Mikrobiologiia, 1978 May-Jun, 47(3), 393 - 5
{2,4,6-trinitrotoluene as a nutritional source for bacteria}; Amerkhanova NN et al.; 2,4,6-Trinitrotoluene (TNT) is one of the most stable toxic substances belonging to nitroaryls which is introduced into water reservoirs with industrial wastes . Its metabolism by microorganisms was studied in this work . The nitrogen of TNT is less accessible for Pseudomonas denitrificans than for Escherichia coli . In the latter case, TNT can be compared with ammonium sulphate . As a source of carbon, TNT is not utilized at all by E . coli and is hardly accessible for Ps . denitrificans . The data obtained in this work are valuable for intensifying the decomposition of TNT in natural and waste waters . This process can be stimulated in the conditions of biological purification of waters by combining waste waters containing TNT with other industrial waters containing accessible organic substances.

Can J Microbiol, 1978 Apr, 24(4), 490 - 2
A cytochrome b-like pigment with a peak at 567 nm in Pseudomonas aeruginosa; Rowe JJ et al.; A cytochrome b - like pigment with an absorption peak at 567 nm was detected in Pseudomonas aeruginosa irrespective of whether the organism was grown aerobically or anaerobically under denitrifying conditions . This pigment has not been reported previously for P . aeruginosa but it has been detected in other denitrifying bacteria including closely related Pseudomonas species.

Mikrobiologiia, 1978 Mar-Apr, 47(2), 325 - 31
{Biological activity of the soils of the rice irrigation systems in the southern Ukraine}; Andreiuk EI et al.; The biological activity of soils was studied in the irrigation systems of the Southern Ukraina . Aerobic microorganisms were found to be widely distributed in all these soils . The cell number of Azotobacter and the activity of nitrogen fixation differed among various irrigation systems . Active nitrogen-fixing microbial associations were isolated from the soils; some of them were capable of fixation of 19.4 mg N per 1 g of assimilated glucose . The microbiological processes of certain irragation systems were characterized by reductive processes such as the intensive growth of sulphate reducing bacteria and the high activity of denitrification . The activities of protease, catalase and dehydrogenase differed among various soils, and were the lowest at a level of ground waters being 0.8 m . Flooding is one of ecological factors affecting the biological activity of the soils of irrigation systems.

Mikrobiologiia, 1978 Mar-Apr, 47(2), 270 - 2
{Specific gravity of the dried biomass of pure bacterial cultures}; Romanenko VI et al.; The weight of wet and dry biomass taken from colonies after growth on MPA was determined in pure bacterial cultures of Pseudomonas denitrificans and Brevibacterium imperiale, and the number and dimensions of bacterial cells in dry preparations of the same colonies were measured by means of membrane filters . The average specific weight of dry biomass was found to be 1.68 and 1.62 . In calculating the weight of bacterial biomass in pure cultures and natural cenoses, its volume should be assayed taking into account the number and dimensions of the cells in dry preparations on membrane filters and multiplying by a coefficient 1.6.

Appl Environ Microbiol, 1978 Feb, 35(2), 247 - 50
Studies on the differential inhibition by azide on the nitrite/nitrous oxide level of denitrification; Sidransky E et al.; A gas chromatographic method was used to demonstrate that nitrite can counteract the inhibition by azide of nitrous oxide reductase activity in denitrifiers . This effect explains why azide (and cyanide) can inhibit nitrogen production from nitrous oxide in these organisms but have little effect on nitrogen production from nitrite . Although the physiological basis by which nitrite opposes the action of azide remains unknown, extensive destruction of azide by nitrite can be ruled out as an explanation.

Can J Microbiol, 1978 Jan, 24(1), 45 - 9
{Denitrification by Bacillus licheniformis}; Pichinoty F et al.; The denitrifying capacity of 15 strains of Bacillus licheniformis was evaluated . In general, N2 production by the cultures on complex media containing NO3- is irregular and quite slow and three of the strains never produce gas . Bacillus licheniformis grows rapidly in anaerobiosis on peptone medium containing NO3- which is reduced to NO2- . None of the strains grow in peptone medium with NO2- or N2O as the respiratory substrate, nor do they grow under an atmosphere of 10% NO-90% N2 . Denitrification was studied in cell suspensions using gas chromatography . N2O production from NO3- or NO2- is always weak at best; nitric oxide is reduced to N2O at an appreciable rate . All the strains synthesize nitrate reductase A in anaerobiosis when NO3- is present . In cell extracts, nitrite reductase activity is always negligible or nil with tetramethyl-p-phenylenediamine as an electron donor.

Can J Biochem, 1978 Jan, 56(1), 13 - 22
Energy transduction in the mitochondrionlike bacterium Paracoccus denitrificans during carbon- or sulphate-limited aerobic growth in continuous culture; Lawford HG; Paracoccus denitrificans was grown in carbon-limited aerobic continuous culture (critical dilution rate (Dc) = 0.48 h-1) . The molar growth yield for carbon (succinate or malate) was constant at about 60 over a broad dilution range (growth rate) from 0.10 to 0.48 h-1 . Measurements of the stoichiometry of proton translocation associated with the oxidation of endogenous substrates yielded a ratio of protons ejected from the cell per atom of oxygen consumed(leads to H+:O) of 8.55 which decreased to 5.85 in the presence of piericidin A (PA), a specific inhibitor of NADH dehydrogenase (EC 1.6.99.3) . With starved cells, the observed leads to H+:O associated with the oxidation of added succinate in the presence of PA was 5.61 . These observed leads to H:O's represent an underestimation since no correction was made for proton backflow during the short interval of respiratory activity . Aerobic growth of Pc . denitrificans in the chemostat becomes sulphate limited at entering concentrations of sulphate less than 300 is microM . Neither the maximum specific growth rate (measured at Dc) nor the observed molar growth yield for succinate decreased under sulphate limitation . The NADH oxidase in electron transport particles prepared from sulphate-limited cells was completely inhibited by PA . The stoichiometry of proton translocation associated with malate oxidation was similarly unaffected by sulphate limitation . It is concluded that (a) the respiratory chain of aerobic, heterotrophically grown Pc . denitrificans possesses three sites of energy conservation, including site III, (b) the number of protons ejected during the transfer of one pair of reducing equivalents along a region of the electron transport chain equivalent to a single energy-coupling site is 3, and (c) that sulphate limitation does not lead to a loss of proton translocation associated with the cytochrome-independent region of the respiratory chain.

J Bacteriol, 1978 Jan, 133(1), 53 - 8
Purification and properties of nitroalkane oxidase from Fusarium oxysporum; Kido T et al.; A nitroalkane-oxidizing enzyme, which was inducibly formed by addition of nitroethane to the medium was purified to homogeneity from an extract of Fusarium oxysporum (IFO 5942) with an overall yield of about 20% . The enzyme catalyzed the oxidative denitrification of 1-nitropropane as follows: CH2(NO2)CH2CH3 + O2 + H2O leads to OHCCH2CH3 + HNO2 + H2O2 . In addition to 1-nitropropane, 3-nitro-2-pentanol, 2-nitropropane, and nitrocyclohexane are good substrates; the enzyme is designated "nitroalkane oxidase" (EC class 1.7.3) . The enzyme has a molecular weight of approximately 185,000 and consists of four subunits identical in molecular weight (47,000) . Flavin adenine dinucleotide was required for the enzyme activity and could be replaced in part by riboflavin 5'-phosphate . The maximum reactivity was found at about pH 8.0 . The enzyme was inhibited significantly by HgCl2, KCN, p-chloromercuribenzoate, and N-ethylmaleimide . The Michaelis constants are as follows: 1-nitropropane, 1.54 mM; 2-nitropropane, 7.40 mM; nitroethane, 1.00 mM; 3-nitro-2-pentanol, 3.08 mM; nitrocyclohexane, 0.90 mM; and flavin adenine dinucleotide, 1.33 micrometer.

Arch Microbiol, 1977 Dec 15, 115(3), 293 - 8
Light-activated, -inhibited and -independent denitrification by a denitrifying phototrophic bacterium; Satoh T; Effects of illumination on denitrification by a freshly isolated denitrifying phototrophic bacterium were investigated . Denitrification activity was induced when cells were grown in either light or darkness in the presence of nitrate without oxygen . Denitrification of nitrate with malate as the electron donor by cells at a phase of exponential growth occurred independently of illumination while that by cells in a stationary phase was activated . Effects of illumination on denitrification varied with electron donors . Using malate or succinate, denitrification by cells in a stationary phase was accelerated by illumination, inhibited when glucose or lactate was used, and independent of illumination when pyruvate was used . Denitrification by cells in an exponential phase was independent of illumination when succinate, malate or pyruvate was used and inhibited by it when glucose or lactate was used . Effects of illumination on the denitrification of nitrite were similar to those involving nitrate . Effects of various inhibitors on denitrification were examined in light-succinate and dark-lactate systems . Differences between the two systems are discussed.

Appl Environ Microbiol, 1977 Dec, 34(6), 806 - 10
Microbial conversion of DL-2-amino-delta2-thiazoline-4-carboxylic acid to L-cysteine and L-cystine: screening of microorganisms and identification of products; Sano K et al.; Microorganisms able to form L-cysteine from DL-2-amino-delta2-thiazoline-4-carboxylic acid (DL-ATC), a chemical intermediate in the synthesis of DL-cysteine, were isolated from soil samples and classified as Pseudomonas sp., Pseudomonas cohaerens, P . desmolytica, and P . ovalis . Thirteen L-cysteine-producing bacteria were also found in among 463 stock cultures representing 37 genera . These were Achromobacter delmarvae . Alcaligenes denitrificans, Bacillus brevis, Brevibacterium flavum, Enterobacter aerogenes, Erwinia carotovora, Escherichia coli, Micrococcus sodonensis, Myocoplana dimorpha, Sarcina lutea, Serratia marcescens, Flavobacterium acidoficum, and Pseudomonas ovalis . In the presence of intact cells of Pseudomonas sp . AJ 3854, 6.1 mg of L-cysteine and/or L-cystine per ml was produced from 10 mg of DL-ATC-3H2O per ml in a molar yield of 100% . This finding suggests that racemization and asymmetric hydrolysis occurred simultaneously in this incubation mixture . After the complete oxidation of cysteine to cystine by aeration in the presence of ferrous ion, crystalline cystine was isolated; its configuration was the L isomer based on data from X-ray diffraction, microbioassay, and optical rotation studies.

Eur J Biochem, 1977 Dec 1, 81(2), 267 - 75
The role of iron-sulfur center 2 in electron transport and energy conservation in the NADH-ubiquinone segment of the respiratory chain in Paracoccus denitrificans; Meijer EM et al.; 1 . The electron paramagnetic resonance spectra at 15 K of reduced membrane particles of Paracoccus denitrificans exhibit resonance signals with g values, line shapes and temperature profile which are similar to the signals of the iron-sulfur centers observed in the NADH-ubiquinone segment of mitochondrial respiratory chains . These iron-sulfur centers are reducible with NADH, NADPH as well as chemically with dithionite . 2 . Sulphate-limited growth of Paracoccus denitrificans results in the loss of an electron paramagnetic resonance signal (gz approximately 2.05, gy approximately gx approximately 1.92) which has properties similar to those of iron-sulfur center 2 of the NADH dehydrogenase of mitochondrial origin . The loss of this signal is accompanied by a decrease in the NADH oxidase and NADH ferricyanide oxidoreductase activities to respectively 30 and 40% of the values found for succinate-limited growth conditions . In addition respiration in membrane particles from sulphate-limited cells loses its sensitivity to rotenone . 3 . Since sulphate-limited growth of Paracoccus denitrificans induces loss of site I phosphorylation {Arch . Microbiol . (1977) 112, 25-34} these observations suggest a close correlation between site I phosphorylation, rotenone-sensitivity and the presence of an electron paramagnetic resonance signal with gz approximately 2.05 and gy approximately gx approximately 1.92.

J Biol Chem, 1977 Nov 10, 252(21), 7826 - 33
Primary structure of a high potential iron sulfur protein from a moderately halophilic denitrifying coccus; Tedro SV et al.; The occurrence of a specific high potential iron-sulfur protein in a halophilic, denitrifying coccus provisionally assigned to the genus Paracoccus has been confirmed through primary structure determination . This protein, known as "HiPIP", has been found previously only in photosynthetic bacteria . The sequence of this 71-residue protein is as similar to the HiPEPs from photosynthetic bacteria as they, in turn, are to one another (average number of identically matching residues is 38%) . Paracoccus HiPIP is a highly acidic protein in accord with general observations on the proteins of halophilic bacteria . A possible explanation for its occurrence in Paracoccus is that gene transfer is involved.

Mikrobiologiia, 1977 Nov-Dec, 46(6), 1034 - 8
{Chemcial aspects of the energy process in nitrate reduction in different representatives of soil microflora}; Il'nina TK et al.; Chemical aspects of dissimilatory nitrate reduction were studied by mass spectrometry in the following soil bacteria: Bacillus filaris, Bacillus polymyxa and Pseudomonas denitrificans . Chemical peculiarity of this process in spore-forming soil bacteria is the simultaneous operation of two energy processes: denitrification and nitrate respiration . The first process is terminated by the formation of molecular nitrogen, the second, by the production of ammonia . The quantitative ratio between these processes demonstrates the advantage of nitrate respiration in the overall energy pathway of nitrate dissimilation . Pseudomonas denitrificans maintains the abilityfor intensive gas production as a result of denitrification upon long storage on artificial media: ca . 34 per cent of the nitrate nitrogen is reduced to gaseous forms of nitrogen.

Appl Environ Microbiol, 1977 Nov, 34(5), 582 - 5
Nitrogen fixation, denitrification, and pleomorphic growth in a highly pigmented Spirillum lipoferum; Eskew DL et al.; A strain of Spirillum lipoferum with intense red pigmentation was isolated from the roots of Cynodon dactylon "Coastal." This isolate vigorously reduced acetylene when grown in N-free, Na-malate, semisolid agar, and it was identical to S . lipoferum strain SP7 by standard taxonomic tests . Both S . lipoferum SP7 and the C . dactylon root isolate displayed the unique features of being denitrifiers as well as N2 fixers . The N2-dependent growth curve was biphasic: cells in younger cultures showed the characteristic spiral shape and motility, but those in older cultures developed larger, nonmotile, cystlike forms . Nitrogenase activity seemed associated only with younger spiral forms . The red pigment may be a b- or c-type cytochrome . The strong red color, which this strain develops, could be used as a marker in evaluating soil inoculation experiments.

Arch Microbiol, 1977 Oct 24, 115(1), 67 - 71
Metabolic regulation of pyruvate kinase isolated from autotrophically and heterotrophically grown Paracoccus denitrificans; Slabas AR et al.; Pyruvate kinase (ATP: pyruvate phosphotransferase (EC 2.7.1.40) was partially purified from both autotrophically and heterotrophically grown Paracoccus denitrificans . The organism grown under heterotrophic conditions contains four times more pyruvate kinase than under autotrophic conditions . The enzyme isolated from both sources exhibited sigmoidal kinetics for both phosphoenolpyruvate (PEP) and ADP . The apparent Km for ADP and PEP in the "autotrophic" enzyme were 0.63 mM ADP and 0.25 mM PEP . The effect of several low molecular weight metabolites on the pyruvate kinase activity was investigated . Ribose-5-phosphate, glucose-6-phosphate and AMP stimulated the reaction at low ADP levels; this stimulation was brought about by an alteration in the apparent Km for ADP . The pyruvate kinases differ in their response to adenine nucleotides, but both preparations seem to be under adenylate control . The results are discussed in relation to the role of pyruvate kinase as a regulatory enzyme in P . denitrificans grown under both autotrophic and heterotrophic conditions.

Mikrobiologiia, 1977 Sep-Oct, 46(5), 898 - 903
{Biological elimination of nitrous oxide under oxidative conditions}; Vedenina IIa et al.; The process of biological N2O elimination under oxidative conditions has been discribed . It was performed by samples of soil, litter, water, ooze, sewage and compost . The process differs from denitrification, is not accompanied with dinitrogen formation and its rate is maximal at 15% of oxygen in the gaseous phase . Acetylene, an inhibitor of denitrification has no effect on elimination of nitrous oxide under oxidative conditions.

Arch Microbiol, 1977 Aug 26, 114(2), 93 - 100
Micromorphology of Gram-negative hydrogen bacteria . I . Cell morphology and flagellation; Aragno M et al.; The cell morphology, the arrangement and fine structure of flagella and the piliation of the following Gram-negative aerobic hydrogen bacteria have been studied: Alcaligenes eutrophus, Alcaligenes paradoxus, Alcaligenes ruhlandii, Pseudomonas flava, Pseudomonas pseudoflava, Pseudomonas palleronii, Pseudomonas facilis, Aquaspirillum autotrophicum, Paracoccus denitrificans, Corynebacterium autotrophicum, and strains MA 2 and SA 35 . The identity of the bacteria was examined by their substrate spectra and type of flagellation . Three types of flagellar fine structure were differentiated . The presence of pili was noted in strains of Alcaligenes paradoxus, Pseudomonas flava, P.pseudoflava, P.palleronii, and P.facilis.

Arch Microbiol, 1977 Aug 26, 114(2), 101 - 10
Micromorphology of Gram-negative hydrogen bacteria . II . Cell envelope, membranes, and cytoplasmic inclusions; Walther-Mauruschat A et al.; The fine structure of the cell envelope, of membrane systems and of cytoplasmic inclusions of Gram-negative aerobic hydrogen bacteria has been studied . The results have been tabulated, and three main groups could be recognized: Group 1: Alcaligenes eutrophus, A.paradoxus, A.ruhlandii, Pseudomonas facilis, P.flava, P.pseudoflava, P.palleronii, and Aquaspirillum autotrophicum; Group 2: "Corynebacterium" autotrophicum and strains MA 2 and SA 35; Group 3: Paracoccus denitrificans . Special structures related to the chemoautotrophic way of life of the hydrogen bacteria were not observed.

Mikrobiologiia, 1977 Jul-Aug, 46(4), 642 - 6
{Relation of proteolytic activity to the ability to assimilate higher n-alkanes in Pseudomonas denitrificans}; Illarionov EF; A correlation between proteolytic activity and the ability to assimilate higher n-alkanes was found while studying proteolysis of gelatin by 284 paraffin-negative mutants of Pseudomonas denitrificans . The mutants were produced by a paraffin-positive strain capable of gelatin proteolytis, but not growing on glucose . If assimilation of the oxidized derivatives of higher n-alkanes, viz . alcohols and aldehydes, is interfered with at a genetical level, the percentage of mutants possessing extracellular proteolytic activity decreases (44 per cent of the mutants have lost the activity) whereas the percentage of mutants capable of glucose assimilation increases . Proteolytis of gelatin can be used as a test for a preliminary selection of strains to be employed in industrial synthesis of the oxidized derivatives of higher n-alkanes, as well as in the control of stability and homogeneity of a population under industrial conditions.

J Biochem (Tokyo), 1977 Jul, 82(1), 307 - 9
Purification and properties of an acid phosphatase of Micrococcus denitrificans distinct from thiamine phosphate phosphatase; Egi Y et al.; To determine whether the acid phosphatase in Micrococcus denitrificans participates in hydrolysis of thiamine phosphate in the synthesis of thiamine pyrophosphate, acid phosphatase was purified 280-fold by conventional procedures, which removed thiamine phosphate phosphatase completely . Studies showed that this acid phosphatase is a different protein from thiamine phosphate phosphatase and that it has no binding site for thiamine phosphate on its active site.

Can J Microbiol, 1977 Jul, 23(7), 903 - 7
Nitrous oxide as end product of denitrification by strains of fluorescent pseudomonads; Greenberg EP et al.; Growing cultures of several strains of Pseudomonas fluorescens and Pseudomonas chlororaphis produced N2O as the only detectable gaseous product of denitrification, and other strains produced N2 as the gaseous end product of denitrification . All of the nitrogen in NO3- or NO2- added to cell suspensions of the N2O-producing strains P . fluorescens PJ 185 and P . chlororaphis B-560 was recovered as N2O . All of the nitrogen in NO3- or NO2- added to cell suspensions of the N2-producing strain P . fluorescens PJ70 was converted to N2 . Cell extracts of P . fluorescens PJ 70, PJ 185, and P . chlororaphis B-560 exhibited NO3- reductase activity when sodium succinate was the electron donor . Reduced nicotinamide adenine dinucleotide and flavine adenine dinucleotide were required to demonstrate NO2- reductase activity in cell extracts.

Can J Microbiol, 1977 Jun, 23(6), 710 - 5
Antagonistic interactions of phylloplane bacteria with Drechslera dictyoides (Drechslera) Shoemaker; Austin B et al.; Strains of Listeria denitrificans (E2), Pseudomonas fluorescens (C37 and C92), and Xanthomonas campestris (D119), isolated from the phylloplane of Lolium perenne (S24), were antagonistic to Drechslera dictyoides (Drechslera) Shoemaker . From in vitro and in vivo experiments it was deduced that their mode of activity included an initial inhibition of spore germination, a retardation in the rate of germ-tube elongation, and ultimately lysis of the hyphae . The effects were expressed on the plant in terms of reduced levels of disease symptoms and sporulation.

Arch Microbiol, 1977 May 13, 113(1-2), 11 - 6
Proton translocation in intack cells of Thiobacillus denitrificans; Tuovinen OH et al.; Proton translocation assessed by the quinacrine fluorescence technique was compared with oxygen uptake during thiosulphate oxidation by cells of Thiobacillus denitrificans . The addition of thiosulphate to cell suspensions resulted in an outwardly directed proton translocation as reflected by an increased quinacrine fluorescence . Compared to the O2 uptake activity, the proton translocating system was much more sensitive to proton conductors, other ionophores and inhibitors of electron transport . The results indicate that (a) the proton-translocation activity (membrane energization) is enhanced in aged cell suspensions, (b) intactness of the cytoplasmic membrane is essential for establishing a protonmotive force in cells, (c) the fluorescence increase and proton translocation are reversible processes, (d) inhibitors of electron transport may also act as proton conductors by altering the integrity of the cytoplasmic membrane.

Ann Microbiol (Paris), 1977 May-Jun, 128A(4), 447 - 58
{Denitrification in a sporulating thermophilic bacterium}; Garcia JL; Denitrification in a thermophile isolated on nitrite containing-medium (5 g/l) was studied by means of Warburg respirometry and gas chromatography . This strain seems to denitrify nitrite more rapidly than nitrate . Extracts of cells grown anaerobically on nitrate have dissimilatory nitrate reductase (type A); extracts of cells grown aerobically without nitrate have raised levels of the two types of nitrate reductase A and B . The optimal temperature for enzyme A activity is 60 degrees C . Nitrite reductase activity was measured using yeast extract as electron donor . For nitric oxide reductase activity, yeast extract is as efficient an electron donor as sodium lactate . Nitrous oxide reductase activity was found only in the 4 000 g supernatant showing the particulate nature of the enzyme . A mixture of FAD, FMN and NADH served as electron donor . Using acetylene as an inhibitor of nitrous oxide reduction in both whole cells and extracts, we showed that this gas is an intermediate compound in the reduction of NO to N2.

Ann Microbiol (Paris), 1977 May-Jun, 128A(4), 433 - 46
{Analysis of various groups of denitrifying microflora in Senegalese paddy soils (author's transl)}; Garcia JL; Dentrifying mesophilic and thermophilic bacteria were looked for in rice paddies of Senegal by culturing samples in medium with high concentrations of nitrate or nitrite (5 g/l) as respiratory substrate . These cultures revealed the existence of two populations . 1) a population of denitrifying mesophiles which tolerate high concentrations of nitrite, these organisms being mostly spore-formers and relatively numerous in these soils; growth studies showed them to be very diverse: a) "nitrite-dependent" bacteria unable to reduce NO-3; b) bacteria highly nitrite-tolerant with rapid growth on 5 g/l nitrite; c) bacteria slightly nitrite-tolerant with weak or no growth on more than 3 g/l nitrite; d) NO-tolerant bacteria which use nitric oxide as respiratory substrate for growth; e) N2O-deficient bacteria unable to grow on nitrous oxide; 2) a population of denitrifying thermophilic spore-formers which are numerous in some soils and tolerate nitrite more or less well . Measuring of the denitrifying activity of washed cells demonstrated that, in general, cells grown anaerobically on nitrite show much more activity than cells grown anaerobically on nitrate . This nitrite-tolerant population seems fairly heterogeneous, but it consists mostly of spore-forming species of the genus Bacillus.

Arch Microbiol, 1977 Apr 1, 112(3), 229 - 38
Localization and stability of hydrogenases from aerobic hydrogen bacteria; Schneider K et al.; Alcaligenes eutrophus strains H 16, B 19, G 27 and N9A contained two different hydrogenases . One enzyme catalyzed the reduction of NAD by hydrogen and was strictly localized in the soluble cell fraction . While the second enzyme was found to be particulate and unable to react with NAD . All other tested strains, Alcaligenes paradoxus SA 29, Pseudomonas facilis, P . palleronii RH 2, Pseudomonas sp . strain GA 3, Paracoccus denitrificans, Aquaspirillum autotrophicum SA 32, and Corynebacterium autotrophicum 14g and 7C contained only a single enzyme exclusively bound to membranes . This was established using fractional centrifugation, indicator enzyme systems, gently methods of cell disintegration and discontinuous sucrose density gradient centrifugation . In cell-free extracts obtained by rough disruption (sonication) of cells, hydrogenase was associated to particles of different size and sedimentation velocity . A partial solubilization of hydrogenase caused by sonication was observed with P . facilis . Without exception, the particulate hydrogenases were found (1) to be unable to reduce pyridine nucleotides, and (2) to reduce methylene blue at an extremely high activity . The eminent reaction rate of 34 micronmoles H2 oxidized per min and mg protein has been determined in particle suspensions of Pseudomonas sp . strain GA 3 . All hydrogenases were stable during storage under hydrogen atmosphere, except the soluble enzyme for A . eutrophus H 16 which was shown to be more stable under aerobic conditions.

J Bacteriol, 1977 Apr, 130(1), 542 - 4
Specific thiamine monophosphate phosphohydrolase in Micrococcus denitrificans; Kawasaki T et al.; A phosphohydrolase specific for thiamine monophosphate was isolated from Micrococcus denitrificans, partially purified approximately 100-fold, and separated from acid phosphatase.

Biochim Biophys Acta, 1977 Mar 15, 481(1), 266 - 78
Sulphur metabolism in Paracoccus denitrificans . Purification, properties and regulation of cysteinyl-and methionyl-tRNA synthetase; Burnell JN et al.; Cysteinyl- and methionyl-tRNA synthetases (EC 6.11.-) were purified 1200- and 1000-fold, respectively, from sonic extracts of Paracoccus denitrificans strain 8944, and kinetics, substrate specificity and regulatory properties were determined using the ATP-PPi exchange reaction . Both enzymes had pH optima of approx . 8 and were inhibited by sulphydryl-group reagents . Cysteinyl-tRNA synthetase catalysed L-selenocysteine- and alpha-aminobutyric acid-dependent ATP-PPi exchange and methionyl-tRNA synthetase catalysed L-homocysteine-, L-selenomethionine- and norleucine-dependent ATP-PPi exchange . Both enzymes were inhibited by O-acetylserine . Cysteinyl-tRNA synthetase activity was stimulated by methionine and methionyl-tRNA synthetase activity was stimulated by sulphide, cysteine, and cysteic acid.

Biochim Biophys Acta, 1977 Mar 15, 481(1), 246 - 65
Sulphur metabolism in Paracoccus denitrificans . Purification, properties and regulation of serine transacetylase, O-acetylserine sulphydrylase and beta-cystathionase; Burnell JN et al.; 1 . Serine transacetylase, O-acetylserine sulphydrylase and beta-cystathionase were purified from Paracoccus denitrificans strain 8944 . 2 . Serin transacetylase was purified 150-fold . The enzyme has a pH optimum between 7.5 and 8.0, is specific for L-serine and is inhibited by sulphydryl-group reagents . The apparent Km values for serine and acetyl-CoA are 4.0 - 10(-4) and 1.0 - 10(-4) M, respectively . Serine transacetylase is strongly inhibited by cysteine . 3 . O-Acetylserine sulphydrylase was purified 450-fold . The enzymes has a sharp pH optimum at pH 7.5 . In addition to catalysing the synthesis of cysteine, O-acetylserine sulphydrylase catalyses the synthesis of selenocysteine from O-acetylserine and selenide . The Km values for sulphide and O-acetylserine are 2.7 - 10(-3) and 1.25 - 10(-3) M, respectively . The enzyme was stimulated by pyridoxal phosphate and was inhibited by cystathionine, homocysteine and methionine . 4 . beta-Cystathionase was purified approx . 50-fold . beta-Cystathionase has a pH optimum between pH 9.0 and 9.5, is sensitive to sulphydryl-group reagents, required pyridoxal phosphate for maximum activity and has an apparent Km for cystathionine of 4.2 - 10 (-3) M . beta-Cystathionase also catalyses the release of keto acid from lanthionine, djenkolic acid and cystine . Cysteine, O-acetylserine, homocysteine and glutathione strongly inhibit beta-cystathionase activity and homocysteine and methionine represses enzyme activity . 5 . O-Acetylserine lyase was identified in crude extracts of Paracoccus denitrificans . The enzyme is specific for O-acetyl-L-serine, requires pyridoxal phosphate and is inhibied by KCN and hydroxylamine . The enzyme has a high Km value for O-acetylserine (50--100 mM).

Biochim Biophys Acta, 1977 Mar 11, 459(3), 546 - 59
Tightly bound nucleotides of the energy-transducing ATPase, and their role in oxidative phosphorylation . I . The Paracoccus denitrificans system; Harris DA et al.; 1 . The coupling ATPase of Paracoccus denitrificans can be removed from the membrane by washing coupled membrane fragments at low salt concentrations . 2 . This ATPase resembles coupling ATPases of mitochondria, chloroplasts and other bacteria . It is a negatively charged protein of molecular weight about 300,000 . An inhibitor protein in bound tightly to the ATPase in vivo, and can be destroyed by trypsin treatment . 3 . ATP and ADP are found tightly bound to the coupling ATPase of P . denitrificans, both in its membrane-bound and isolated state . The ATP/ADP ratio on the enzyme is greater than one . 4 . Under de-energised condtions, the bound nucleotides are not available to the suspending medium . When the membrane is energised however, the bound nucleotides can exchange with added nucleotides and incorporate 32Pi . 32Ppi is incorporated into the beta and gamma positions of the bound nucleotides, but beta-labelling probably does not occur on the coupling ATPase . 5 . Uncouplers inhibit the exchange of the free nucleotides or 32Pi into the bound nucleotides, while venturicidin (an energy transfer inhibitor) and aurovertin stimulate the exchange . 6 . The response of the bound nucleotides to energisation is consistent with their being involved directly in the mechanism of oxidative phosphorylation.

Can J Microbiol, 1977 Mar, 23(3), 300 - 5
Denitrification by N2-fixing Sprillum lipoferum; Neyra CA et al.; Forty-nine N2-fixing strains of Spirillum lipoferum isolated from a wide range of plant roots and soils were examined for reduction of NO3- . All strains reduced NO3-to NO2- . Thirty of the strains further reduced NO2-with production of gas . Examiniation of representative strains of the putative denitrifiers showed that they produced both N2O and C2H4 in the presence of 0.1 atm of C2H2 . Strains which did not reduce NO2-with production of gas produced C2H4 but ont N2O in the presence of C2H2 . This is the first report of a N2-fixing bacterium able to bring about denitrification of NO3.

Arch Microbiol, 1977 Mar 1, 112(2), 225 - 7
Metabolic regulation of the glucose-6-phosphate dehydrogenase from Paracoccus denitrifcans grown on glucose/nitrate; Slabas AR et al.; Glucose-6-phosphate dehydrogenase (D-glucose-6-phosphate : NADP+ L-oxidoreductase EC 1.1.1.49) isolated from Paracoccus denitrificans grown on glucose/nitrate exhibits both NAD+-and NADP+- linked activities . Both activities have a pH optimum of pH 9.6 (Glycine/NaOH buffer) and neither demonstrates a Mg2+ requirement . Kinetics for both NAD(P)+ and glucose-6-phosphate were investigated . Phosphoenolpyruvate inhibits both activities in a competitive manner with respect to glucose-6-phosphate . ATP inhibits the NAD+-linked activity competitively with respect to glucose-6-phosphate but has no effect on the NADP+-linked activity . Neither of the two activities are inhibited by 100 muM NADH but both are inhibited by NADPH . The NAD+-linked activity is far more sensitive to inhibition by NADPH than the NADP+-linked activity.

Arch Microbiol, 1977 Feb 4, 112(1), 25 - 34
Energy conservation during aerobic growth in Paracoccus denitrificans; Meijer EM et al.; Paracoccus denitrificans was aerobically grown in chemostat culture with succinate or gluconate as carbon source . Due to the presence of two phosphorylation sites in the respiratory chain and the absence of branching, theoretical P/O ratios of 1.71 and 1.82 were calculated for cells growing respectively with succinate and gluconate as carbon source . Using these data, 95% confidence intervals for the P/O ratio were determined, via a mathematical model, at 0.91-1.15 and 1.00-1.37 for sulphate-limited cultures, with respectively succinate and gluconate as carbon source . These results and measurements of P/O ratios in membrane particles and of proton translocation in whole cells have led to the conclusion that site I phosphorylation is affected under sulphate-limited conditions . Under conditions of carbon source-limitation the endogenous leads to H+/O ratio is about 7-8 . Average values of 3.40 and 4.78 were respectively found for sulphate-limited succinate- and gluconate grown cells . For starved cells, oxidizing succinate as exogenous substrate, the leads to H+/O ratios were determined at about 3-4, independent of the growth limiting factor . It is concluded that the number of protons ejected per pair of electrons per energy-conserving site (leads to H+/site ratio) is about 3-4, instead of 2 as postulated by the chemiosmotic hypothesis.

Arch Microbiol, 1977 Feb 4, 112(1), 17 - 23
Energy conservation during nitrate respiration in Paracoccus denitrificans; van Verseveld HW et al.; P/2e ratios were calculated from anaerobic chemostat cultures of Paracoccus denitrificans with nitrogenous oxides as electron acceptor . P/2e ratios were calculated, using the YmaxATP values determined for aerobic cultures . When succinate was the carbon and energy source the average P/2e values of the sulphate- and succinate-limited cultures with nitrate as electron acceptor were 0.5 and 0.7, respectively, and of the nitrite-limited culture 0.9 . With gluconate as carbon and energy source and average P/2e values of the gluconate-limited with nitrate as electron acceptor and nitrate limited cultures were 0.9 and 1.1, respectively . leads to H+/O ratios measured in cells obtained from sulphate-, succinate, nitrite-, gluconate- and nitrate-limited cultures yielded respective average values of 3.4, 4.5, 3.5, 4.8 and 6.2 for endogenous substrates . From our data we conclude that sulphate- and nitrite- limitation causes the loss of site I phosphorylation . Nitrite has no influence on the maximum growth yield on ATP . We propose that metabolism in heterotrophically grown cells of Paracoccus dentrificans is regulated on the level of phosphorylation in the site I region of the electron transport chain.

J Bacteriol, 1977 Feb, 129(2), 815 - 20
Reduction of iron and synthesis of protoheme by Spirillum itersonii and other organisms; Dailey HA Jr et al.; Membranes from Spirillum itersonii reduce ferric iron to ferrous iron with reduced nicotinamide adenine dinucleotide or succinate as a source of reductant . Iron reduction was measured spectrophotometrically at 562 nm using ferrozine, which chelates ferrous iron specifically . Reduced nicotinamide adenine dinucleotide or succinate was also effective as a source of iron . The effects of respiratory inhibitors suggested that reduction of iron occurs at one or more sites on the respiratory chain before cytochrome c . Reduction of iron and synthesis of protoheme with the physiological reductants were also observed with crude extracts of other bacteria, including Rhodopseudomonas spheroides, Rhodopseudomonas capsulata, Paracoccus denitrificans, and Escherichia coli . The effect of oxygen upon reduction of iron and formation of protoheme was examined with membranes from S . itersonii, using succinate as a source of reductant . Both systems were inhibited by oxygen, but this effect was completely reversed by addition of antimycin A . We conclude that reduced components of the respiratory chain serve as reductants for ferric iron, but with oxygen present they are oxidized preferentially by the successive members of the chain . This could be a mechanism for regulating synthesis of heme and cytochrome by oxygen.

J Biol Chem, 1977 Jan 25, 252(2), 574 - 82
Multiple low spin forms of the cytochrome c ferrihemochrome . EPR spectra of various eukaryotic and prokaryotic cytochromes c; Brautigan DL et al.; 1 . Despite the same methionine-sulfur:heme-iron:imidazole-nitrogen hemochrome structure observed by x-ray crystallography in four of the seven c-type eukaryotic and prokaryotic cytochromes examined, and the occurrence of the characteristic 695 nm absorption band correlated with the presence of a methionine-sulfur:heme-iron axial ligand in all seven proteins, they fall into two distinct classes on the basis of their EPR and optical spectra . The horse, tuna, and bakers' yeast iso-1 cytochromes c have a predominant neutral pH EPR form with g1=3.06, g2=2.26, and g3=1.25, while the bakers' yeast iso-2 and Euglena cytochromes c, the Rhodospirillum rubrum cytochrome c2, and the Paracoccus denitrificans cytochrome c550 all have a predominant neutral pH EPR form with g1=3.2, g2=2.05, and g3=1.39 . The ferricytochromes with g1=3.06 have a B-Q splitting that is approximately 150 cm-1 larger than the ferricytochromes with g1=3.2 . 2 . Each of the cytochromes displays up to four low spin EPR forms that are in pH-dependent equilibrium and can all be observed at near neutral pH . As the pH is raised the predominant neutral pH form is converted into two forms with g1=3.4 and g1=3.6, identified by comparsion with model compounds and other heme proteins as epsilon-amino:heme-iron:imidazole and bis-epsilon-amino:heme-iron ferrihemochromes, respectively . 3 . The pK for the conversion of the predominant neutral pH EPR form into the alkaline pH forms is the same as the pK for the disappearance of the 695 nm absorption band for the cytochromes, even though these pK values range over 2 pH units . This confirms that the g1=3.06 and g1=3.2 forms contain the methionine-sulfur:heme-iron axial ligand while the g1=3.4 and the g1=3.6 forms do not . 4 . At extremes of pH, the horse and bakers' yeast iso-1 proteins display several high and low spin forms that are identified, showing that a variety of protein-derived ligands will coordinate to the heme iron including methionine and cysteine sulfur, histidine imidazole, and lysine epsilon-amine . 5 . The spectrum of horse cytochrome c with added azide, cyanide, hydroxide, or imidazole as axial ligands has also been examined . 6 . From a comparison of the EPR and optical spectral characteristics of these groups of cytochromes with model compounds, it is suggested that the difference between them is due to a change in the hydrogen bonding or perhaps even in the protonation of N-1 of the heme iron-bound histidine imidazole.

J Biol Chem, 1977 Jan 10, 252(1), 212 - 8
Nitrogen 15 tracer studies on the pathway of denitrification in Pseudomonas aeruginosa; St John RT et al.; The pathway of anaerobic reduction of nitrite to nitrogen gas (N2) by cell suspensions of the denitrifier, Pseudomonas aeruginosa, was studied using the techniques of gas chromatography and mass spectrometry . While release of nitrous oxide (N2O) is not normally detected during the reduction of nitrite to N2 by this organism, 15N from {15N}nitrite nevertheless can be trapped quantitatively as 15N2O in a pool of added N2O . In such experiments the abundance of 15N in N2O always exceeds that in product N2, consistent with the absence of a major reductive route from nitrite to N2 which by-passes N2O . During the reduction of a mixture of {15N}nitrite and nitric oxide (NO), 15NO produced at most only in trace amounts . The final products are chiefly 15N2 and 14N2 with only a small fraction of the scrambled product, 14N15N . Much of the 14N15N can be accounted for as an artifact caused by traces of molecular oxygen, which promote the conversion of NO to nitrite by autooxidation and thereby degrade slightly the isotopic purity of {15N}nitrite . Nitrous oxide shows all the properties of a free obligatory intermediate during the denitrification of nitrite to N2 by P . aeruginosa, whereas NO does not . The inability to trap 15NO in a pool of NO indicates that NO is not a free obligatory intermediate in the reduction of nitrite . The small mole fractions of 14N15N produced from a mixture of {15N}nitrite and NO require that the main reductive pathways for these nitrogen oxides cannot share any freely diffusible mono-nitrogen intermediate in common . The simplest interpretation is that nitrite and NO are denitrified by separate pathways, at least prior to the formation of the first bi-nitrogen compound.

Ann Microbiol (Paris), 1977 Jan, 128A(1), 75 - 87
{Study of 14 denitrifying soil bacteria of the "pseudomonas stutzeri" group isolated by enrichment culture in the presence of nitrous oxide (author's transl)}; Pichinoty F et al.; The strains were isolated from soil by enrichment in a liquid minimal medium containing ethanol, acetate, succinate, L-malate or tartrate, under an N2O atmosphere at 32 degrees C . All fourteen strains can use the following 25 sources of carbon and energy under aerobic conditions: glycerate, ethanol, propanol, acetate, butyrate, malonate, succinate, glutarate, sebacate, glycollate, L-lactate, D-lactate, L-malate, DL-3-hydroxybutyrate, pyruvate, fumarate, itaconate, mesaconate, crotonate, L-alpha-alanine, D-alpha-alanine, L-leucine, asparagine, L-tyrosine, and L-proline . They hydrolyze Tween 80 but not gelatin . Nitrate is used as nitrogen source . Nitrate reductase A and respiratory nitrite reductase are present . Four of the strains are clearly and easily distinguishable from the others on the basis of six characters: special morphology of colonies; in ability to use isovalerate and DL-valine, inability to use glucose, absence of exocellular amylase, and high level of metapyrocatechase . Their G + C content is 66-67% . One of the strains is distinct from the others by the yellow pigmentation of its colonies, its ability to use D-glucuronate, trehalose, D-sorbitol and citraconate, ability to grow at 4 degrees but not at 40 degrees, and a lower G + C content: 63% . One strain accumulates poly-beta-hydroxybutyrate . This work confirms the well-known, wide variability of the bacteria belonging to the P . stutzeri group . Denitrification by two of the strains was quantitatively studied using cell suspensions . Cells from NO-3-containing anaerobic cultures reduce NO-3, NO-2 and NO to N2O and N2; they reduce slowly N2O to N2 . Cells grown in anaerobic cultures under N2O also reduce NO-3, NO-2 and NO to N2O and N2 but they reduce N2O rapidly to N2.

J Gen Microbiol, 1977 Jan, 98(1), 231 - 8
Aerobic and anaerobic bacterial respiration monitored by electrodes; John P; A technique is described by which both oxygen and nitrate (or nitrate or chlorate) levels were continuously monitored during bacterial respiration . Paracoccus (Micrococcus) denitrificans and Escherichia coli oxidizing succinate rapidly ceased to reduce nitrate when oxygen was available, and equally rapidly commenced nitrate reduction when all the oxygen had been consumed . By contrast, membrane vesicles isolated from P . denitrificans reduced oxygen and nitrate simultaneously . The respiratory nitrate reductase in intact cells of P . denitrificans appeared to be inacessible to chlorate present in the reaction medium, and it is suggested that the nitrate reductase is orientated on the plasma membrane so that nitrate gains access from the inner (cytosolic) face.

J Bacteriol, 1977 Jan, 129(1), 559 - 61
Internally generated reduced nicotinamide adenine dinucleotide as a substrate for glycine transport by membrane vesicles of Paracoccus denitrificans; Tucker AN et al.; Internally generated reduced nicotinamide adenine dinucleotide was the most efficient substrate for glycine transport by membrane vesicles of Paracoccus denitrificans.

Appl Environ Microbiol, 1976 Dec, 32(6), 808 - 18
Nitrate removal in closed-system aquaculture by columnar denitrification; Balderston WL et al.; The columnar denitrification method of nitrate-nitrogen removal from high-density, closed system, salmonid aquaculture was investigated and found to be feasible . However, adequate chemical monitoring was found to be necessary for the optimization and quality control of this method . When methanol-carbon was not balanced with inlet nitrate-nitrogen, the column effluent became unsatisfactory for closed-system fish culture due to the presence of excess amounts of nitrite, ammonia, sulfide, and dissolved organic carbon . Sulfide production was also influenced by column maturity and residence time . Methane-carbon was found to be unsatisfactory as an exogenous carbon source . Endogenous carbon could not support high removal efficiencies . Freshwater columns adpated readily to an artificial seawater with a salinity of 18% without observable inhibition . Scanning electron microscopy revealed that the bacterial flora was mainly rod forms with the Peritricha (protozoa) dominating as the primary consumers . Denitrifying bacteria isolated from freshwater columns were tentatively identified as species of Pseudomonas and Alcaligenes . A pilot plant column was found to behave in a manner similar to the laboratory columns except that nitrite production was never observed.

Biochim Biophys Acta, 1976 Oct 13, 449(1), 1 - 9
Nitrate, fumarate, and oxygen as electron acceptors for a late step in microbial heme synthesis; Jacobs NJ et al.; Nitrate can serve as anaerobic electron acceptor for the oxidation of protoporphyrinogen to protoporphyrin in cell-free extracts of Escherichia coli grown anaerobically in the presence of nitrate . Two kinds of experiments indicated this: anaerobic protoporphyrin formation from protoporphyrinogen, followed spectrophotometrically, was markedly stimulated by addition of nitrate; and anaerobic protoheme formation from protoporphyrinogen, determined by extraction procedures, was markedly stimulated by addition of nitrate . In contrast, anaerobic protoheme formation from protoporphyrin was not dependent upon addition of nitrate . This was the first demonstration of the ability of nitrate to serve as electron acceptor for this late step of heme synthesis . Previous studies with mammalian and yeast mitochondria had indicated an obligatory requirement for molecular oxygen at this step . In confirmation of our previous preliminary report, fumarate was also shown to be an electron acceptor for anaerobic protoporphyrinogen oxidation in extracts of E . coli grown anaerobically on fumarate . For the first time, anaerobic protoheme formation from protoporphyrinogen, but not from protoporphyrin, was shown to be dependent upon the addition of fumarate . The importance of these findings is 2-fold . First, they establish that enzymatic protoporphyrinogen oxidation can occur in the absence of molecular oxygen, in contrast to previous observations using mammalian and yeast mitochondria . Secondly, these findings help explain the ability of some facultative and anaerobic bacteria to form very large amounts of heme compounds, such as cytochrome pigments, when grown anaerobically in the presence of nitrate or fumarate . In fact, denitrifying bacteria are known to form more cytochromes when grown anaerobically than during aerobic growth . An unexpected finding was that extracts of another bacterium, Staphylococcus epidermidis, exhibited very little ability to oxidize protoporphyrinogen to protoporphyrin as compared to E . coli extracts . This finding suggests some fundamental differences in these two organisms in this key step in heme synthesis . It is known that these two facultative organisms also differ in that E . coli synthesizes cytochrome during both aerobic and anaerobic growth, while Staphylococcus only synthesizes cytochromes when grown aerobically.

Ann Microbiol (Paris), 1976 Oct, 127B(3), 351 - 61
{A new, sporulating, denitrifying, mesophilic bacterium: Bacillus azotoformans N . SP . (author's transl)}; Pichinoty F et al.; The described bacterium was isolated by enrichment culture in peptone broth inoculated with garden soil, pasteurized and then put to incubate under N2O at 32 degrees . It is a Gram-negative rod, motile with peritrichous flagella, and producing oval spores without exosporium in swollen sporangia . However, cells have the thick walls, mesosomes and persistant septa characteristic of Gram-positive bacteria . It lacks fermentative activity, does not attack carbohydrates, has complex growth requirements, and will grow anaerobically only if one of the following electron acceptors is present: NO3, NO2, N2O, S4O6, and fumarate . Nitrate, nitrite, and nitrous oxide are denitrified with production of N2 . The microorganism is mesophilic, gives a positive oxidase reaction, synthesizes a type of c cytochrome, and does not hydrolyse gelatin, starch nor "Tween 80" . The following enzymes are present: nitrate reductase A, respiratory nitrite reductase, tetrathionate and fumarate reductases, L-glutamate dehydrogenase, and superoxide dismutase . The following enzymes are absent: thiosulfate reductase, urease, lecithinase, arginine dihydrolase, L-alanine dehydrogenase, phenylalanine desaminase, and catalase . The GC% of its DNA is 39 . The bacterium described can be considered to be a new species . We propose the name Bacillus azotoformans n . sp.

Biotechnol Bioeng, 1976 Oct, 18(10), 1393 - 1403
Use of a tapered fluidized bed as a continuous bioreactor; Scott CD et al.; Reactor systems based on tapered fluidized beds are being developed for aqueous bioprocesses in which adhering microorganisms or immobilized active biological fractions are used . The use of a fluidized bed prevents biomass buildup, accommodates particulates in the feed stream, is compatible with gas sparging, and allows easy removal or addition of the active materials . The tapered reactor tends to stabilize the fluidized bed, thus allowing a much wider range of operating conditions . Preliminary experimental results and an empirical mathematical model of the tapered bed indicate that bed stability is associated with a decreasing velocity and void-fraction profile up the bed and the pressure drop across the bed decreases with increasing flow rates . The tapered fluidized bed bioreactor is being evaluated for use in the enzymatic production of hydrogen, microbiological denitrification, and microbiological degradation of coal conversion aqueous waste streams . The enzyme catalyzed conversion of lactose to glucose and galactose was used in the evaluation of the reactor concept.

Can J Microbiol, 1976 Oct, 22(10), 1509 - 17
Thermothrix thioparus gen . et sp . nov . a facultatively anaerobic facultative chemolithotroph living at neutral pH and high temperature; Caldwell DE et al.; Thermothrix thioparus gen . et ep . nov . occurs naturally in a New Mexico hot spring at a temperature of 74 degrees C, a pH of 7.0, and a HS- concentration of 1 mg/litre . The organism is gram-negative, non-motile, 0.5-1.0 X 3-20 mum, and forms cell chains up to 1 cm in length . The resulting filaments do not possess a sheath . Sulfur is deposited extracellularly . The organism was isolated using an autotrophic medium with HS- as the energy source and NO3- as the terminal electron acceptor . Anaerobically either NO2- or NO3- is required, NO2- is formed from NO3-, and no observable gas is evolved . Oxygen can also be used as the terminal electron acceptor, but growth is poor because of the decreased solubility of O2 at temperatures required for growth . Alternate energy sources used aerobically and anaerobically include hexose, HS-, SO3-, and S2O3= . The temperature optimum is 70-73 degrees C and growth occurs from 62 to 77 degrees C . The organism's thermal and physiological characteristics are compared to those of Bacillus stearothermophilus, Methanobacterium thermoautotrophicum, Sulfolobus acidocalderius, Thermus aquaticus, Thermus flavus, as well as Thiobacillus denitrificans, the latter being the only other facultatively anaerobic chemolithotroph which has been isolated and described.

Biochim Biophys Acta, 1976 Aug 18, 442(2), 227 - 38
The mitochondrial ribosomes of Neurospora crassa . II . Comparison of the proteins from Neurospora crassa mitochondrial ribosomes with ribosomal proteins from Neurospora cytoplasm, from rat liver mitochondria and from bacteria; van den Bogert C et al.; 1 . It has been shown by Datema et al . (Datema, R., Agsteribbe, E . and Kroon, A.M . (1974) Biochim . Biophys . Acta 335, 386--395) that Neurospora mitochondria isolated in a Mg2+-containing medium (or after homogenization of the mycelium in this medium and subsequent washing of the mitochondria in EDTA-containing medium) possess 80-S ribosomes; mitochondria homogenized and isolated in EDTA medium yield 73-S ribosomes . The ribosomal proteins of the subunits of 80-S and 73-S ribosomes were compared by two-dimensional electrophoresis . The protein patterns of the large, as well as of the small subunits are very similar but not completely identical; the most conspicuous difference is that the large subunit of 80 S contains about eight more proteins than the large subunit of 73 S . 2 . The contamination by Neurospora cytoplasmic 77-S ribosomes in the 80-S preparations, if present, is only minor . 3 . Neurospora cytoplasmic ribosomes contain 31 proteins in the large, and 21 proteins in the small subunit . 4 . Neurospora 80- mitochondrial ribosomes contain 39 proteins in the large, and 30 proteins in the small subunit 30 proteins . 5 . Rat liver mitochondrial ribosomes contain 40 proteins in the large and at least 30 proteins in the small subunit . About 50% of these proteins has an isoelectric point below pH 8.6 . 6 . The pattern of Paracoccus denitrificans is very similar to that of other bacterial ribosomes, the large subunit contains 29, the small subunit 18 proteins.

Arch Microbiol, 1976 Aug, 109(1-2), 101 - 3
Cysteine and S-sulfocysteine biosynthesis in phototrophic bacteria; Hensel G et al.; Forteen species (17 strains) of phototrophic bacteria as well as one strain of Thiobacillus denitrificans were tested for cysteine synthase and S-sulfocysteine synthase . All strains contain cysteine sythase active with O-acetylserine; only the Chromatiaceae, two species of the Rhodospirillaceae and T . denitrificans contain S-sulfocysteine synthase . In six species repression by different sulfur compounds in the medium was studied . In Chromatium vinosum, cysteine synthase was found to be constitutive, while in the Rhodospirillaceae tested the enzyme is repressed by sulfide . Thiosulfate had a derepressive effect in Rhodopseudomonas globiformis but strongly repressed cysteine synthase in R . sulfidophila and R . palustris . Cysteine had only moderate effects with the species tested.

J Biol Chem, 1976 Jul 10, 251(13), 4033 - 46
The structure of Paracoccus denitrificans cytochrome c550; Timkovich R et al.; The crystal structure of Paracoccus (formerly Micrococcus) denitrificans cytochrome c550 has been solved by x-ray diffraction to a resolution of 2.45 A . In both amino acid sequence and molecular structure it is evolutionarily homologous with mitochondrial cytochrome c from eukaryotes and photosynthetic cytochrome c2 from purple non-sulfur bacteria . All of these cytochromes c have the same basic folding pattern, with surface insertions of extra amino acids in c550 . Various strains of c2 have all, some, or none of the extra insertions observed in c550 . The hydrophobic heme environment, position of aromatic rings, and structure and environment of the heme crevice, are virtually identical in cytochromes c55o, c, and c2 . Radical changes observed at all regions on the molecular surface except the heme crevice argue for the importance of the crevice and the exposed edge of the heme in the transfer of electrons to and from the cytochrome molecule.

Arch Microbiol, 1976 Jul, 108(3), 265 - 9
Rhodopseudomonas sphaeroides forma sp . denitrificans, a denitrifying strain as a subspecies of Rhodopseudomonas sphaeroides; Satoh T et al.; From polluted water of a lagoon pond a new type of denitrifying photosynthetic purple bacteria was isolated . With respect to morphology, fine structure, photopigments, requirement for growth factors, the range of utilization of organic substrates for phototrophic growth and DNA base ratio, the denitrifying strains show the closest resemblance to Rhodopseudomonas sphaeroides and were therefore described as a subspecies named R . sphaeroides forma sp . denitrificans . The new isolates grow well with nitrate anaerobically in the dark accompanying the evolution of nitrogen gas . They cannot assimilate nitrate as the nitrogen source for growth.

Mikrobiologiia, 1976 JUL-AUG, 45(4), 602 - 6
{Chemistry of denitrification in sporogenous soil bacteria}; Il'ina TK et al.; Soil sporeforming denitrifying bacteria, Bacillus filaris and Bacillus polymyxa, differ by their cultural-morphological and physiological characteristics, but are similar in the chemistry of dissimilating nitrate reduction . Two processes occur simultaneously: denitrification yielding gaseous nitrogen forms, and nitrate respiration upon which nitrates are reduced to ammonia . The ratio between the two depends on physico-chemical conditions of the environment . The chemistry of dissimilating nitrate reduction by sporeforming bacteria differs therefore from nitrate transformation by other denitrifying microorganisms: Pseudomonas, Micrococcus, Rhizobium, Achromobacter, which, according to the published evidence, are capable only of denitrification.

J Bacteriol, 1976 Jun, 126(3), 1030 - 6
Pathway of thiamine pyrophosphate synthesis in Micrococcus denitrificans; Sanemori H et al.; The pathway of thiamine pyrophosphate (TPP) biosynthesis, which is formed either from exogeneously added thiamine or from the pyrimidine and thiazole moieties of thiamine, in Micrococcus denitrificans was investigated . The following indirect evidence shows that thiamine pyrophosphokinase (EC 2.7.6.2) catalyzes the synthesis of TPP from thiamine: (i) {35S}thiamine incubated with cells of this microorganism was detected in the form of {35S}thiamine; (ii) thiamine gave a much faster rate of TPP synthesis than thiamine monophosphate (TMP) when determined with the extracts; and (iii) a partially purified preparation of the extracts can use thiamine, but not TMP, as the substrate . The activities of the four enzymes involved in TMP synthesis from pyrimidine and thiazole moieties of thiamine were detected in the extracts of M . denitrificans . The extracts contained a high activity of the phosphatase, probably specific for TMP . After M . denitrificans cells were grown on a minimal medium containing 3 mM adenosine, which causes derepression of de novo thiamine biosynthesis in Escherichia coli, the activities of the four enzymes involved with TMP synthesis, the TMP phosphatase, and the thiamine pyrophosphokinase were enhanced two- to threefold . These results indicate that TPP is synthesized directly from thiamine without forming TMP as an intermediate and that de novo synthesis of TPP from the pyrimidine and thiazole moieties involves the formation of TMP, followed by hydrolysis to thiamine, which is then converted to TPP directly . Thus, the pathway of TPP synthesis from TMP synthesized de novo in M . denitrificans is different from that found in E . coli, in which TMP synthesized de novo is converted directly to TPP without producing thiamine.

Mol Biol (Mosk), 1976 May-Jun, 10(2), 551 - 60
{Membrane proteins of the hydrocarbon oxidation system in Pseudomonas denitirficans}; Illarionov EF; Pseudomonas denitrificans membranes have been isolated . Difference of membranes in peculiar protein fractions on the account of mutation in the oxidation system of higher n-alkanes is revealed . Reorganization of membrane connected with the change of protein showing the property of structural protein and taking part in alkane oxidation is observed . Participation of structural protein in providing substrate specificity of oxidation complex is supposed.

J Biol Chem, 1976 Apr 25, 251(8), 2197 - 206
Amino acid sequence of Paracoccus denitrificans cytochrome c550; Timkovich R et al.; The amino acid sequence of Paracoccus (formerly Micrococcus) denitrificans cytochrome c550 has been established by a combination of standard chemical techniques and interpretation of a 2.5 A resolution x-ray electron density map . Peptides derived from a trypsin digest were chemically sequenced, and then ordered by fitting them to the density map . The amino acid compositions of chymotryptic peptides confirmed the x-ray map ordering the tryptic peptides . The amino acid sequence of this respiratory, prokaryotic cytochrome with 134 residues is discussed in relation to those of eukaryotic respiratory cytochrome c (103 to 113 amino acids), and prokaryotic, photosynthetic c2 (103 to 124 amino acids) . At the primary structure level, c and c550 differ no more from cytochromes c2 than the various cytochromes c2 do from one another . It is suggested that the respiratory electron transport chain in prokaryotes and eukaryotes is a relatively late evolutionary offshoot of the photosynthetic electron transport chain in purple non-sulfur bacteria.

Appl Environ Microbiol, 1976 Apr, 31(4), 504 - 8
Blockage by acetylene of nitrous oxide reduction in Pseudomonas perfectomarinus; Balderston WL et al.; Suspensions of denitrifying cells of Pseudomonas perfectomarinus reduced nitrate and nitrate as expected to dinitrogen; but, in the presence of acetylene, nitrous oxide accumulated when nitrate or nitrate was reduced . When supplied at the outset in place of nitrate and nitrate, nitrous oxide was rapidly reduced to dinitrogen by cells incubated in anaerobic vessels in the absence of acetylene . In the presence of 0.01 atmospheres of acetylene, however, nitrous oxide was not reduced . Ethylene was not produced, nor did it influence the rate of nitrous oxide reduction when provided instead of acetylene . Cells exposed to 0.01 atmospheres of acetylene for as long as 400 min were able to reduce nitrous oxide after removal of acetylene at a rate comparable to that of cells not exposed to acetylene . Acetylene did not affect the production or functioning of assimilatory nitrate or nitrite reductase in axenic cultures of Enterobacter aerogenes or Trichoderma uride . While exposed to acetylene, bacteria in marine sediment slurries produced measurable quantities of nitrous oxide from glucose- or acetate-dependent reduction of added nitrate . Possible use of acetylene blockage for measurement of denitrification in unamended marine sediments is discussed.

Arch Microbiol, 1976 Apr 1, 107(3), 241 - 7
Oxidative phosphorylation in Micrococcus denitrificans: calculation of the P/O ratio in growing cells; Van Verseveld HW et al.; P/O ratios were measured in membrane particles obtained from cells of Micrococcus denitrificans, while growing on different carbon sources . The membrane particles obtained from cells growing actively on glucose, succinate, ethanol and propanol as the carbon and energy sources catalyzed oxidative phosphorylation and yielded respective P/O ratios of 1.4, 1.2, 0.8, and 0.5 with NADH, and 0.8, 0.6, 0.6, and 0.5 with succinate as the electron donors . Not such a difference in P/O ratio is observed in intact resting cells grown with different carbon sources . It is concluded that the influence of the carbon source is probably directed towards the efficiency of oxidative phosphorylation in membrane particles and not in the growing cells . For the aerobic carbon source-limited chemostat cultures the following maximum growth yields were determined: 40.2 and 34.2 for succinate and oxygen, 41.7 and 36.5 for malate and oxygen, 81.4 and 39.4 for mannitol and oxygen, and 77.8 and 43.4 for gluconate and oxygen respectively . With a mathematical model (de Kwaadsteniet et al., in press) the P/O ratio was valued at 1.4-1.7 . YATP at mu=0.2 was valued at 8.7-10.9; YmaxATP at 9.6-13.2 and me at 0.6-4.5 for the most precise experiment (gluconate-limited) . The calculation of these growth parameters has been discussed.

Ann Microbiol (Paris), 1976 Apr, 127(3), 401 - 14
{Nitric oxide production in rice soils (author's transl)}; Garcia JL; Nitric oxide gas evolution from nitrite was studied in vitro in three rice soils by gas chromatography . Autoclaved soils showed an NO evolution when supplemented with nitrite . Yet, when temperature of incubation, soil pH, soil moisture content and nitrite concentration were varied in the three soils, and with addition of nitrite reductase inhibitors, it appeared in one soil that NO production was partially a biological process . Thus, NO formation was two times as high in non-sterile soil as in sterile soil, and decreased when the temperature increased . Optimal NO production occurred at about neutrality and increased with increasing soil moisture content; moreover, this NO formation increased much less than in the other two soils with increasing nitrite concentration . Finally, the first soil contained three times more denitrifying bacteria tolerating a high nitrite concentration (5 g/1) that the other soils.

J Biochem (Tokyo), 1976 Feb, 79(2), 435 - 40
Change in the ratio of cytochrome oxidase activity to nitrite reductase activity of Pseudomonas aeruginosa nitrite reductase with the kind of C-type cytochrome used as an electron donor; Yamanaka T; The ratio between the nitrite reductase and cytochrome oxidase activities of Pseudomonas aeruginosa nitrite reductase {EC 1.9.3.2.} varies with kind of C-type cytochrome used as the electron donor . Withe cytochrome c-548, 554 (Micrococcus sp.), the nitrite reductase activity is greater than the cytochrome oxidase activity, while the former is smaller than the latter with cytochrome c-554 (Navicula pelliculosa) . The aerobic oxidation catalyzed by this enzyme of denitrifying bacterial ferrocytochrome c is greatly accelerated on addition of nitrite, while that of the algal ferrocytochrome c is not affected or is even depressed by the salt . An accelerative effect of nitrite is generally observed with many kinds of C-type cytochromes which react with the enzyme very or fairly rapidly . The difference in the ratio of the two activities of the enzyme seems to arise according to whether or not nitrite affects the interaction of C-type cytochrome with the enzyme.

Antonie Van Leeuwenhoek, 1976, 42(3), 349 - 54
The isolation and properties of a denitrifying bacterium of the genus Flavobacterium; Pichinoty F et al.; A previously undescribed denitrifying bacterium was isolated from soil . The cells are small gram-negative rods, asporogenous, and non-motile . Colonies become yellow after long exposure to light . This colouring is due to the production of a carotenoid pigment . The organism shows no fermenting activity, and grows only in the presence of one of the following electron acceptors: NO2, N2O, and O2 . It does not reduce nitrate . It gives a positive oxidase test and has a cytochrome c and catalase . It requires no growth factors, is a chemoorganotroph and uses only sugars as carbon and energy supply . The DNA base composition is 40.8 moles percent GC . Although presenting the physiological characteristics of a pseudomonad, the organism described has been placed in the genus Flavobacterium because of its pigmentation and its low GC percentage.

Ann Nutr Aliment, 1976, 30(5-6), 645 - 59
{Denitrification of waters on the way from surface to underground levels in a karstic area}; Caumartin V et al.; The failure of the biological processes of waters' recycling in their passing through the soil occurs more and more frequently in calcareous areas . This led us to consider the problem of conditions necessary to the good development of the biological activity . This uses enzymatic reactions activated by chemical elements in very low concentrations: the oligo-elements . The experimental study, in drainage basin in a calcareous area, consisted in finding the percentage of oligo-elements in the waters, in the soils and in the parent rocks . This allowed us to draw a map of the probable lack of oligo-elements and thus to foresee the vulnerability of phreatic waters.

Mikrobiologiia, 1976 Jan-Feb, 45(1), 20 - 2
{Hydrogen and carboxide bacteria belonging to the microflora of degradation}; Zavarzin GA; The following bacteria oxidizing hydrogen and/or carbon monoxide were shown by cultivating in the concentration gradient of acetate, lactate, and glucose, to belong to the microflora of dispersal: Hydrogenomonas eutropha Z-1, H . pantotropha Z-11, Pseudomonas carboxydoflava Z-1107, Achromobacter carboxydus Z-1171, Paracoccus denitrificans, and Alcaligenes paradoxus.

Zentralbl Bakteriol Parasitenkd Infektionskr Hyg, 1976, 131(8), 673 - 7
{No stimulation of the growth of microorganisms by repair-substances (author's transl)}; Mutze B; By means of manometric technique the influence of X-ray-repairsubstances on the growth and respiration of Micrococcus denitrificans, Micrococcus radiodurans and Saccharomyces cerevisiae was investigated . Though these substances are stimulating the development of higher plants, there is no effect on growth and respiration of these microorganisms.

Arch Microbiol, 1975 Dec 31, 106(3), 165 - 9
Microbial assimilation of alkyl nitro compounds and formation of nitrite; Kido T et al.; 66 representative strains of bacteria, yeasts and fungi were tested for their ability to grow in a semidefined medium containing 0.5% nitroethane as a nitrogen source . About half of them were found capable of growing in the medium . Hansenula beijerinckii, Candida utilis, and Penicillium chrysogenum were most active in assimilating nitroethane . 2-Nitropropane inhibited growth of most of the microorganisms tested in a medium containing 0.2% peptone and 0.2% glycerol . Hansenula mrakii was found to grow rapidly in the nitroethane-peptone medium after a lag phase . Nitrite was accumulated in the culture fluid after the phase of logarithmic multiplication, and increased with increase of the growth, followed by a decline after the maximum growth . The alkyl nitro compounds were oxidatively denitrified to form nitrite by the crude enzyme from Hansenula mrakii . Nitroethane was generally a poor substrate, but was the best inducer to produce the nitro compounds oxidizing enzyme . 2-Nitro-propane and nitroethane were enzymatically oxidized to nitrite, and acetone and acetaldehyde, respectively, which were isolated as 2,4-dinitrophenylhydrazones and identified . Nitrite formed was found to be reduced into ammonia by the intact cells and also the crude enzyme.

J Mol Evol, 1975 Dec 31, 7(1), 87 - 100
The history of inorganic nitrogen in the biosphere; Broda E; When in the primeval atmosphere ammonia approached exhaustion, bacteria resembling clostridia developed mechanisms for nitrogen fixation . The fixation was continued by the photosynthetic bacteria . In the later, oxidizing, atmosphere the combined activities of the nitrificants and the denitrificants could lead to a large-scale cyclic regeneration of free nitrogen . The possibility of a descent of the nitrificants from hypothetical photosynthetic bacteria, which used ammonia as electron donor, is discussed . The anoxygenic atmosphere contained no nitrate, and therefore neither nitrate fermentation nor nitrate respiration were precursors of aerobic respiration . This evolved from photosynthesis . In nitrate fermentation, nitrate serves only as an incidental electron acceptor; this process is merely an evolutionary sideline . Nitrate respiration evolved from aerobic respiration . While in present conditions the reaction of nitrogen with oxygen and water to give nitrate is exergonic and possibly occurs at a low rate, the antagonistic action of the denitrificants maintains the stationary concentrations of nitrogen and oxygen in the air.

Arch Microbiol, 1975 Nov 7, 105(3), 339 - 41
Sulfur metabolism in Thiobacillus denitrificans evidence for the presence of a sulfite reducatase activity; Schedel M et al.; The relatively high specific sulfite reductase activity of 25 mU/mg protein was found in extracts from Thiobacillus dentrificans . The absorption spectrum of the partially pruified enzyme was similar to the siroheme containing sulfite reductases from other sources . It is suggested that the T . denitrificans sulfite reductase may function during the oxidation of reduced sulfur compounds.

Biokhimiia, 1975 Nov-Dec, 40(6), 1175 - 84
{The relation of membrane proteins to primary oxidation of higher ri-alkanes by Pseudomonas denitrificans}; Illarionov EF; Protein composition of enriched with cell walls membrane preparations from two Ps . denitrificans mutants is comparatively studied . Mutants have a genetic blocking of first steps of higher n-alkanes oxidation . Differences in three protein components are found using disc electrophoresis in a system containing sodium dodecylsulphate . This is supposed to be an evidence of possible relation of changed mutant proteins to enzymatic alkanes oxidation.

Mikrobiologiia, 1975 Nov-Dec, 44(6), 1064 - 7
{Infrared spectra of extreme and obligate thermophilic bacteria of the genus Thermus}; Egorova LA et al.; A recording double-beam spectrophotometer UR-10 was used to obtain IR spectra of the extreme thermophilic non-sporeforming bacterium Thermus flavus, the obligate thermophilic non-sporeforming bacterium Thermus ruber, the thermotolerant bacterium Pseudomonas thermophilus, the sporeforming bacterium Bacillus stearothermophilus, and the mesophilic bacteria Pseudomonas aeruginosa, Ps . denitrificans, Flavobacterium breve, Flavobact . arborescens . No significant differences have been found in the IR spectra of these bacteria.

Biochem J, 1975 Sep, 150(3), 569 - 71
The autotrophic growth of Micrococcus denitrificans on Methanol; Cox RB et al.; Ribulose bisphosphate carboxylase is present at a high specific activity in extracts of methanol-grown Microccus denitrificans . Enzymic and physiological evidence indicates that, during growth on methanol, the ribulose bisphosphate cycle is the route of carbon assimilation.

Biochem J, 1975 Sep, 150(3), 527 - 36
The reversibility of active sulphate transport in membrane vesicles of Paracoccus denitrificans; Burnell JN et al.; An uncoupler-sensitive active transport of sulphate into membrane vesicles prepared from the plasma membrane of Paracoccus denitrificans (previously Micrococcus denitrificans) can be driven by respiration or by a trans-membrane pH gradient (alkaline inside) generated by the addition either of KCL ( in the presence of nigericin) or of NH4CL . Valinomycin does not substitute for nigericin . Respiration-driven transport is observed in right-side-out vesicles but not in inside-out vesicles, whereas transport driven by the addition of KCL (in the presence of nigericin) or of NH4CL is observed in both types of membrane vesicle . The active transport of sulphate into these vesicles is shown to be carrier-mediated by its sensitivity to thiol-group reagents . It is proposed that the sulphate carrier in the plasma membrane of P . denitrificans operates by a mechanism of electroneutral proton symport, and is capable of actively transporting sulphate in either direction across the plasma membrane, but that in whole cells respiration-driven proton expulsion drives the accumulative uptake of sulphate.

Prikl Biokhim Mikrobiol, 1975 Jul-Aug, 11(4), 519 - 22
{Effect of the growth phase and nutrient medium on the survival of lyophilized cells of Pseudomonas denitrificans}; Arkadyeva AZ et al.; The influence of the growth phase and cultivation condition of Pseudomonas denitrificans on the survival of the culture after lyophilization was examined . The culture removed for drying in the stationary phase showed the highest resistance to lyophilization . The cells dried at the beginning of exponential phase displayed enhanced sensitivity to lyophilization . Addition to the cultivation medium (meat-peptone broth) of Tween-80 (0.25%) caused an increase of proteins, lipids and polysaccharides in cells and an enhancement of their telerance to lyophilization.

Biochim Biophys Acta, 1975 Jun 11, 394(1), 65 - 75
Physiological basis for preferential uptake of D-alpha-aminoadipate over the L-isomer by Alcaligenes denitrificans; Pekala PH et al.; Alcaligenes denitrificans, pre-incubated with D-alpha-aminoadipate and assayed for L-isomer uptake without removal of extracellular D-isomer, exhibits a reduced rate of uptake and a reduced level at which steady state is achieved . During D- or L-isomer uptake, intracellular alpha-aminoadipate is exclusively the L-configuration . These data are consistent with an intracellular, mediated reduction in L-isomer uptake as the physiological basis for preferential D-alpha-aminoadipate uptake by A . denitrificans growing on racemic alpha-aminoadipate . Translocated D-alpha-aminoadipate is rapidly metabolized to form an L-isomer pool which subsequently reduces the rate of L-isomer uptake and the level at which steady state occurs resulting in a preferred D-isomer uptake . Competitive inhibition of L-alpha-aminoadipate uptake by the D-isomer or a difference in the maximum rates of uptate uptake is an inducible process expressed only in the presence of that compound and while uptake of L-alpha-animoadipate is also inducible there is a low rate of constitutive uptake . While L-alpha-aminoadipate uptake occurs against a concentration gradient, uptake of the D-isomer is not against a gradient . D- and L-isomer uptake are active processes since both are inhibited by azide, cyanide and 2,4-dinitrophenol.

Mikrobiologiia, 1975 May-Jun, 44(3), 442 - 8
{Positive mutation as regards n-alkane oxidation in Pseudomonas denitrificans}; Illarionov EF; Differences in the overall protein composition were studied in the wild-type and mutant cells of Pseudomonas denitrificans . Pleiotropic mutation was established, which was characterized by quantitative and qualitative changes in at least 6 to 8 protein fractions and corresponded to the appearance of 2 to 3 steps of oxidation of higher n-alkanes, as had been found earlier in biochemical experiments . New enzymatic functions may appear on the basis of genetically determined proteins available, upon reorganization of the intracellular structure caused by propagating changes induced by mutation.

J Gen Microbiol, 1975 May, 88(1), 11 - 9
Energy yield of denitrification: an estimate from growth yield in continuous cultures of Pseudomonas denitrificans under nitrate-, nitrite- and oxide-limited conditions; Koike I et al.; The molar growth yields of Pseudomonas denitrificans, for nitrate, nitrite and nitrous oxide, were determined in chemostat culture under electron acceptor-limited conditions . Glutamate was used as the source of energy, carbon and nitrogen . The catabolic pattern was identical, irrespective of the terminal electron acceptors . The molar growth yields, corrected for maintenance energy, were 28-6 g/mol nitrate, 16-9 g/mol nitrite and 8-8 g/mol nitrous oxide . The energy yield, expressed on an electron basis, was proportional to the oxidation number of the nitrogen: nitrate (plus 5), nitrite (plus 3) and nitrous oxide (plus 1) . It was concluded that oxidative phosphorylation occurs to a similar extent in each of the electron transport chains associated with the reduction of nitrate to nitrite, nitrite to nitrous oxide and nitrous oxide to nitrogen.

J Gen Microbiol, 1975 May, 88(1), 1 - 10
Growth yield of a denitrifying bacterium, Pseudomonas denitrificans, under aerobic and denitrifying conditions; Koike I et al.; The effciency of denitrification, or anaerobic respiration, in Pseudomonas denitrificans was investigated, using growth yield as an index . Glutamate was mainly used as the sole source of energy and carbon . In batch culture, the growth yield per mole of electrons transported through the respiratory system under denitrifying conditions was about half that under aerobic conditions . Similar figures were also obtained in chemostat cultures under glutamate-limited conditions . The decrease in growth yield under denitrifying conditions could be due to the restriction of phosphorylation associated with nitrate reduction to nitrogen gas.

Arch Microbiol, 1975 Mar 12, 103(1), 31 - 6
Reduction of oxidized inorganic nitrogen compounds by a new strain of Thiobacillus denitrificans; Baldensperger J et al.; Denitrification by Thiobacillus denitrificans "RT" strain was investigated using manometry and gas chromatography . 1 . From nitrate, resting cells produced only nitrogen anaerobically with thiosulfate as the electron donor . The data suggest that nitrate was assimilated and dissimilated by the same nitrate reductase, assayed with benzyl-viologen as the electron donor . 2 . From nitrite, whole cells produced nitric oxide, nitrous oxide and nitrogen, using thiosulfate as the electron donor; nitrogen was the final product of the reduction . Crude extract reduced nitrite to nitrogen with p-phenylene-diamine and dimethyl-p-phenylene diamine as the electron donors, and produced nitric oxide, nitrous oxide and nitrogen with tetramethyl-p-phenylene-diamine as the electron donor . Nitrite was reduced to nitric oxide and nitrous oxide by crude extract using ascorbate-phenazine methosulfate as the electron donor . 3 . From nitric oxide, whole cells produced nitrous oxide and nitrogen using thiosulfate as the electron donor, nitrogen was the final reduction product . Nitric oxide was reduced to nitrous oxide by crude extract with the ascorbate-phenazine methosulfate system . 4 . Whole cells reduced nitrous oxide to nitrogen with thiosulfate as the electron donor . It was not possible to detect any nitrous oxide reductase activity in crude extract . 5 . A scheme was of denitrification by Thiobacillus denitrificans "RT" strain.

J Biochem (Tokyo), 1975 Mar, 77(3), 627 - 32
The participation of cytochromes in the reduction of N20 to N2 by a denitryfying bacterium; Matsubara T; The oxidation of cytochromes during the reduction of N2O to N2 by a denitrifying bacterium was studied spectrophotometrically . The reduced b- and c-type cytochromes are partially oxidized when N2O is added to intact cells reduced with lactate under anaerobic conditions . The oxidation of cytochromes is inhibited non-competitively by azide, cyanide, 2,4-dinitrophenol and CuSO4, which inhibit the reduction of N2O to N2 . In the presence of each inhibitor at a high concentration, at which the reduction of N2O to N2 is perfectly inhibited, cytochromes are not oxidized by N2O, while when an adequate, low concentration of inhibitor is added, b-type cytochrome is partially oxidized but c-type cytochrome is apparently not oxidized . In cell-free extracts, prepared by the sonic disruption of cells, that have entirely lost their activity in the reduction of N2O to N2, cytochromes are not oxidized by N2O . From the above results, it was concluded that b-type and c-type cytochromes should participate in the electron transport mechanism of the reduction of N2O to N2.

J Clin Microbiol, 1975 Jan, 1(1), 61 - 4
Recognition of Pseudomonas pickettii in the clinical laboratory: biochemical characterization of 62 strains; Riley PS et al.; Pseudomonas pickettii strains were studied to determine the characteristics essential for their identification in the clinical microbiology laboratory . Preliminary investigations indicated that these glucose-oxidizing, denitrifying, gram-negative rods were quite similar to an unclassified group of clinical isolates designated VA-2 . Gas liquid chromatography of trimethylsilyl derivatives of whole cell hydrolysates of P . pickettii and VA-2 strains yielded nearly identical elution profiles . The VA-2 cultures were concluded to be probable strains of P . pickettii . A method is presented for differentiating cultures of P . pickettii from other similar bacteria encountered in clinical specimens.

Prikl Biokhim Mikrobiol, 1975 Jan-Feb, 11(1), 118 - 26
{Quantitative analysis of polypeptides by disc electrophoresis in pore gradients}; Illarionov EF et al.; The quantitation of components in a complex mixture of proteins of Pseudomonas denitrificans separated by disc-electrophoresis in the linear pore gradient of polyacrylamide gel was studied . The problem of a poor staining of proteins in the presence of a detergent was solved by a high resolving power photography . A linear correlation between the amount of protein in the fraction and the intensity of amide black staining was extablished . In comparison to the wild type of P . denitrificans the aldehyde negative mutant showed significant changes in protein fractions amounting to 30% of total protein, according to the densitometrical data . It is suggested that the changes are related to the protein migration in fractions rather than to an additional synthesis in different protein fractions.

Mikrobiologiia, 1975 Jan-Feb, 44(1), 160 - 2
{Microflora of active ooze participating in the decomposition of sulfanilic acid}; Orshanskaia FB et al.; Microflora of domestic water can be a source of active ooze adapted to sulphanilic acid . Adaptation of the microflora to sulphanilic acid at a concentration of 170-200 mg/l takes 6 to 8 days . The microflora of active ooze, immediately after adaptation, consists mainly of Pseudomonas species, Ps . denitrificans, Ps . fluorescens, Ps . striata, Ps . putida, etc., and also of Achromobacter stutzeri, Achromobacter flavum, Mycobacterium phlei, Mycobacterium mucosum, Bacillus mesentericus, Bac . cereus, saccharomyces cerevisiae, Schizosaccharomyces pombe, and Rhodotorula glutinus . The number of the species decreased as a result of long cultivation of active ooze on a minimal medium with sulphanilic acid as a sole source of carbon and nitrogen; the following strains prevailed: Ps . putida, Ps . eisenbergii, strains of Mycobacterium phlei and Flavobacterium solare . The isolated strains of Ps . putida and Ps . eisenbergii decomposed sulphanilic acid by 60.0--79.5 percent, and together with Mycobacterium phlei by 100 percent during 4 to 7 days . The ability to oxidize sulphanilic acid decreased after storage . Addition to the medium of other sources of carbon, nitrogen and vitamins did not restore the lost ability of the microorganisms to decompose sulphanilic acid.

Biochem J, 1975 Jan, 146(1), 191 - 204
The identification and biosynthesis of siderochromes formed by Micrococcus denitrificans; Tait GH; 1 . Micrococcus denitrificans excretes three catechol-containing compounds, which can bind iron, when grown aerobically and anaerobically in media deficient in iron, and anaerobically in medium with a high concentration of Ca2+ . 2 . One of these compounds was identified as 2,3-dihydroxybenzoic acid (compound I), and the other two were tentatively identified as N1N8-bis-(2,3-dihydroxybenzoyl)spermidine (compound II) and 2-hydroxybenzoyl-N-L-threonyl-N4{N1N8-bis-(2,3-dihydroxybenzoyl)}spermidine (compound III) . 3 . The equimolar ferric complex of compound III was prepared; compound III also forms complexes with Al3+, Cr3+ and Co2+ ions . 4 . Cell-free extracts from iron-deficient organisms catalyse the formation of compound II from 2,3-dihydroxybenzoic acid and spermidine, and of compound III from compound II, L-threonine and 2-hydroxybenzoic acid; both reactions require ATP and dithiothreitol, and Mg2+ stimulates activity . The enzyme system catalysing the formation of compound II has optimum activity at pH 8.8 Fe2+ (35muM), Fe3+ (35muM) and Al3+ (65muM) inhibit the reaction by 50 percent . The enzyme system forming compound III has optimum activity at pH 8.6 . Fe2+ (110 muM), Fe3+ (110 muM) and Al3+ (135 muM) inhibit the reaction by 50 percent . 5 . At least two proteins are required for the formation of compound II, and another two proteins for its conversion into compound III . 6 . The changes in the activities of these two systems were followed after cultures became deficient in iron . 7 . Ferrous 1,10-phenanthroline is formed when a cell-free extract from iron-deficient cells is incubated with the ferric complex of compound III, succinate, NADH and 1,10-phenanthroline under N2.

Am J Med Technol, 1975 Jan, 41(1), 3 - 9
Identification of nonfermentative gram-negative bacteria in the clinical laboratory; Kantor LT et al.; A simplified, concise scheme was developed for the identification of nonfermentative, gram-negative bacteria which have most frequently been reported in the literature as definite or possible agents of human disease . These organisms included apyocyanogenic Pseudomonas aeruginosa, P . fluorescens, P . putida, P . stutzeri, P . maltophilia, P . putrefaciens, P . cepacia, P . alcaligenes, FLAVOBACTERIUM SPECIES, Bordetella bronchiseptica, Acinetobacter anitratum (Herellea vaginicola), A . Iwoffi (Mima polymorpha), Moraxella species, Alcaligenes odorans and Alcaligenes species . The tests used for identification included production of cytochrome oxidase, amylase, deoxyribonuclease, gelatinase, urease and Beta-galactosidase; motility; oxidation of one per cent glucose and ten per cent lactose; fluorescence; indole, hydrogen sulfide and nitrogen gas production; denitrification of nitrites; growth at 42C; penicillin sensitivity and production of an aromatic odor and greenish discoloration on blood agar . Using this scheme, 85 per cent of 243 isolates (unknowns and reference strains) were identified to genus and species . Of the 15 per cent remaining, 11 per cent were identified as alkaline organisms and four per cent were unidentifiable.

Mikrobiologiia, 1975 Jan-Feb, 44(1), 151 - 5
{Characteristics of sulfur bacteria from lakes of the Mari ASSR}; Vainshtein MB; Five karst lakes were investigated in the Mari Autonomous Republic . The vertical distribution of thionic bacteria in water was correlated to the distribution and content of dissolved sulphides . The concentration of thionic bacteria was higher in more productive lakes . A symbiotic culture of thionic and denitrifying bacteria, but not Thiobacillus denitrificans, was isolated from water of these lakes.

What Is Botulism?, What Is Cell Biology?, What Is Biotechnology?, What Is MIC?, What Is Biofilm?, a, Microorganism, n, Microbes, n, Bacteria, c, Bacteriology, s, Microbiology, c, Haemophilus, i, Microbiological, n, Functional genomics, c, Salmonella typhimurium, a, Salmonella typhimurium, n, Achromobacter, e, Yeasts, n, Streptococcal, c, Growth media, c, Salmonella typhimurium, a, Thermophiles, i, Growth media, i, S. cerevisiae, i, Sepsis, n, Streptococcal, r, Microorganisms, r, Enterococci, i, Antibiotics, a, Escherichia coli, i, Campylobacter, a, Microorganism

Scientific Publications - Work Done by Microbiology Reader Bioscreen C
Agricultural Microbiology Anaerobic Microbiology Antimicrobial Susceptibility Artificial Atmosphere Bioassay of Antibiotics Biofilm Microbiology Bioreactor Technology Biotechnology Cell Biology Clinical Microbiology Environmental Microbiology Experiments with Yeast	Fermentation Food Microbiology Functional Genomics Gene Technology Growth Media Development Growth Rate and Lag Time Industrial Microbiology Medical/Pharmaceutical Field Microbiological Assay Microbiological Research Microbiology of Cosmetics go to a specific theme...	Military Microbiology Molecular Microbiology Mutagenicity and Genotoxicity Oral Microbiology Patents Postantibiotic Studies Soil Microbiology Spore Microbiology Veterinary Microbiology Waste/Wastewater Treatment Water Microbiology Wine Microbiology

� 2005 Transgalactic Ltd (manufacturer of Bioscreen C software) | Privacy Statement | P.O. Box 1393, 00101 Helsinki, Finland, phone: +358 9 85172920, fax: +358 9 8749481, e-mail: microbiology@bionewsonline.com

Last modified: May 25, 2005