characterization studies on the membrane-bound adenosine triphosphatase (atpase) of azotobacter vinelandii.the adenosinetriphosphatase (atpase) (ec activity in azotobacter vinelandii concentrates in the membranous r3 fraction that is directly associated with azotobacter electron transport function. sonically disrupted azotobacter cells were examined for distribution of atpase activity and the highest specific activity (and activity units) was consistently found in the particulate r3 membranous fraction which sediments on ultracentrifugation at 144 000 x g for 2 h. when the sonication time in ...1975141
the pyruvate-dehydrogenase complex from azotobacter vinelandii. 2. regulation of the activity.the presence of activators(amp and sulphate) or inhibitors(acetyl-coa) has no influence on the hill coefficient of the s-shaped pyruvate--velocity curve of either the pyruvate-nad+ overall reaction(h equals 2.5) or that of the pyruvate-k3fe(cn)6 activity of the first enzyme (h equals 1.3). ph studies indicated that the hill coefficient is dependent on subunit ionization within the pyruvate-containing complex and not on those in the free complex. it is concluded that pyruvate conversion rather th ...19751251
physiological factors affecting transformation of azotobacter vinelandii.cells of azotobacter vinelandii (atcc 12837) can be transformed by exogenous deoxyribonucleic acid towards the end of exponential growth. transformation occurs at very low frequencies when the deoxyribonucleic acid is purified or when the transformation is carried out in liquid medium. optimal transformation occurs on plates of burk nitrogen-free glucose medium containing either high phosphate (10 mm) or low calcium (0 to 0.29 mm) content. higher levels of calcium are inhibitory, whereas magnesi ...19763492
regulation of respiration and nitrogen fixation in different types of azotobacter vinelandii.the levels of the adenine nucleotides, pyridine nucleotides and the kinetical parameters of the enzymes of the entner-doudoroff pathway (glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase) were determined in azotobacter vinelandii cells, grown under o2- or n2-limiting conditions. it was concluced that the levels of both the adenine nucleotides and pyridine nucleotides do not limit the rate of sucrose oxidation. experiments with radioactive pyruvate and sucrose show that the r ...19764324
some properties of the pyruvate carboxylase from pseudomonas fluorescens.the pyruvate carboxylase of pseudonomas fluorescens was purified 160-fold from cells grown on glucose at 20 degrees c. the activity of this purified enzyme was not affected by acetyl-coenzyme a or l-aspartate, but was strongly inhibited by adp, which was competitive towards atp. pyruvate gave a broken double reciprocal plot, from which two apparent km values could be determined, namely 0-08 and 0-21 mm, from the lower and the higher concentration ranges, respectively. the apparent km for hco3 a ...19764579
biochemistry and physiology of bacterial ribonucleases. 19766997
influence of sewage discharge on nitrogen fixation and nitrogen flux from coral reefs in kaneohe bay, hawaii.nitrogen fixation was investigated in kaneohe bay, oahu, hawaii, a subtropical eutrophic estuary, by using the acetylene reduction technique on algal samples. no active, planktonic, n2-fixing blue-green algae or bacteria were observed. however, calothrix and nostoc capable of fixing n2 were cultured from navigational buoys and dead coral heads. nitrogen fixation associated with these structures was greater in the middle sector than in the south and north sectors of the estuary. experiments demon ...19767198
atp-dependent calcium transport in isolated membrane vesicles from azotobacter vinelandii.membrane vesicles from azotobacter vinelandii o prepared by osmotic lysis of spheroplasts in tris (hydroxymethyl) aminomethane/acetate buffer (ph 7.8) contain a latent adenosine triphosphatase (atpase). the atpase can be activated when the vesicles are incubated in the presence of an electron donor (d-lactate) and a mixture of adenosine diphosphate and inorganic phosphate or by controlled treatment with trypsin. after the atpase is activated, the membrane vesicles in the presence of adenosine tr ...19769392
the effects of ph and temperature on the assay of superoxide dismutase.a simple and reliable method for the measurement of superoxide dismutase (ec activity is described. the method is based on a linear inhibition of the reduction of acetylated cytochrome c by superoxide dismutase.197610065
regulation of the tricarboxylic acid cycle and poly-beta-hydroxybutyrate metabolism in azotobacter beijerinckii grown under nitrogen or oxygen limitation.azotobacter beijerinckii was grown in ammonia-free glucose/mineral salts media in chemostat culture under oxygen or nitrogen limitation. selected enzymes of the tricarboxylic acid cycle and poly-beta-hydroxybutyrate metabolism were monitored in relation to oxygen supply for both steady and transition states. two dissolved oxygen concentrations were used for the nitrogen-limited steady state to investigate the possible effects of respiratory protection of nitrogenase on these enzymes. the levels ...197613143
an alginate lysate from azotobacter vinelandii phage.the alginate depolymerase associated with bacteriophage infection of azotobacter vinelandii has been used in the analysis of sodium alginate. the enzyme degraded the polysaccharide to a series of oligouronides each containing a terminal 4-deoxy-alpha-l-erythro-hex-4-enopyranuronosyl residue. analysis of these oligouronides, together with kinetic information, indicated that the enzyme was specific for mannuronic acid-containing regions of the polyuronide. the specificity of the enzyme made it pos ...197713144
regulation of nitrogenase activity in microorganisms. 197616045
studies on the priming specificity of polyribonucleotides on azotobacter vinelandii polynucleotide phosphorylase. 197718453
substrate kinetic isotope effects in dehydrogenase coupled active transport in membrane vesicles of escherichia coli. 197719035
effect of pressure upon the fluorescence of various flavodoxins.the effects of hydrostatic pressure in the range of 10(-3) to 11 kbar on the fluorescence of flavodoxins from peptostreptococcus elsdenii, desulfovibrio vulgaris, azotobacter vinelandii, and clostridium mp were investigated. the first three flavoproteins showed under high pressure enhancements of flavin fluorescence of over 50 times resulting from the release of flavin mononucleotide from the protein complex. the clostridial flavodoxin showed a very much smaller fluorescence change. at ph 7.5 th ...197720943
adenylosuccinate synthetase from azotobacter vinelandii: purification, properties and steady-state kinetics. 197721629
proton-coupled sodium uptake by membrane vesicles from azotobacter vinelandii. 197825893
the glutamine synthetase from azotobacter vinelandii: purification, characterization, regulation and localization.the glutamine synthetase (ec from the n2-fixing bacterium azotobacter vinelandii was purified to homogeneity by heat treatment, ammonium sulfate precipitation and ion-exchange chromatography. the following molecular parameters were determined: molecular weight 640 000, subunit molecular weight 53 000, partial specific volume 0.710 cm3/g, isoelectric point 4.6, amino acid composition. most of the molecules are composed of 12 identical subunits but active oligomers of other degrees of pol ...197829757
electron-paramagnetic-resonance studies on the redox properties of the molybdenum-iron protein of nitrogenase between +50 and -450 mv.the midpoint potentials, em, for the oxidation of the characteristic e.p.r. signal with g values near 4.3, 3.7 and 2.01, of the nitrogenase mo-fe proteins from a number of bacteria were measured. they were 0mv for clostridium pasteurianum, -42mv for azotobacter chroococcum and azotobacter vinelandii, -95mv for bacillus polymyxa and -180mv for klebsiella pneumoniae mo-fe proteins at ph 7.9. the oxidations were thermodynamically reversible for the proteins from a. chroococcum, a. vinelandii and k. ...197830448
inosine nucleosidase from azotobacter vinelandii. purification and enzyme catalyzing the hydrolysis of purine nucleosides was found to occur in the extract of azotobacter vinelandii, strain o, and was highly purified by ammonium sulfate fractionation, deae-cellulose chromatography, hydroxylapatite chromatography and gel filtration on sephadex g-150. a strict substrate specificity of the purified enzyme was shown with respect to the base components. the enzyme specifically attacked the nucleosides without amino groups in the purine moiety: inosine gave the ma ...197831149
dynamics of microbial population in soil as influenced by simazine and ecological factors.simazine, even at normal rates of application, showed toxicity to bacteria fungi. it was less toxic to actinomycetes, since toxicity up to 20 ppm of the herbicide was not observed. on the contrary, the normal rate of simazine stimulated both azotobacter and actinomycetes population. the interaction of simazine with soil ecological factors, such as temperature, moisture, ph, and organic matter, affected soil microbial population differently. simazine was relatively less toxic to bacteria under ac ...197831746
purification and properties of azotobacter vinelandii glutamine synthetase. 197935099
[metabolism of ammonium compounds by azotobacter chroococcum (author's transl)].a study on the metabolism of ammonium sulphate, amino acids, peptides, and nutrient broth by azotobacter chroococcum is presented in this paper. some of the amino acids studied lowered the ph of the medium while others alkalinized it. after prolonged incubation desamination could be observed. peptides were hydrolyzed in some cases, although glycyl-glycyl-glycin was not degraded. a certain amount of growth could be observed with peptone as a sole source of carbon. both nitrogen fixation and growt ...197938607
the purification of glutamine synthetase from azotobacter and other procaryotes by blue sepharose chromatography.we report the facile purification of glutamine synthetase (l-glutamate: ammonia ligase (adenosine 5'-diphosphate-forming), ec in both the adenylylated and unadenylylated form, from azotobacter vinelandii atcc 12837. a general affinity column, which used as an affinity ligand reactive blue 2 dye (cibacron blue) covalently linked to agarose, was employed as an efficient first step of purification. further purification to electrophoretic homogeneity employed deae-cellulose chromatography a ...197939606
structure of pyridine nucleotide transhydrogenase from azotobacter vinelandii.1. pyridine nucleotide transhydrogenase of azotobacter vinelandii purified by affinity chromatography consists of a mixture of polydisperse rods at neutral ph. no other structures are seen by electron microscopy. 2. at high ph (8.5--9.0) the rods depolymerize. complete depolymerization can be achieved in 0.1 m tris-cl ph 9.0. the depolymerized enzyme has a molecular weight of 421000 (sedimentation equilibrium), its sedimentation coefficient s20, w = 15 s and its stokes' radius rs = 7 nm. since g ...197939756
the catalytic site of amp nucleosidase. substrate specificity and ph effects with amp and formycin 5'-po4. 197940976
ecological studies on azotobacter in egyptian soils.the present survey includes 156 representative soil samples. results obtained confirm the richness of egyptian soils, particularly the nile valley soils, in azotobacter (60% of the samples contained greater than 10(3) colonies/g soil). colony counts were lower than mpn estimations. glucose is recommended for use in plating medium. among the environmental factors affecting azotobacter densities in soils of egypt are: organic carbon content, total soluble salt content, ph and type of the soil, dep ...197944932
effect of ruthenium on nitrogen fixation by some nitrogen fixers.the effect of ruthenium chloride in the culture media on the nitrogen-fixing ability of the three nitrogen fixers (unidentified species of azotobacter, designated here as d3, b3, and b), isolated from allahabad soil, was studied. it was observed that the nitrogen-fixing ability of the organisms is much increased in presence of 25-75 micro m concentration of ruthenium chloride in the culture media, while sugar consumption remains more or less steady. also, if mg nitrogen fixed/g carbon consumed i ...197944933
proceedings: pressure and temperature dependence of the cooperative interactions in azotobacter vinelandii nitrogenase. 197550813
effect of dicumarol on the growth of some soil microorganisms.the effect of dicumarol on growth of selected soil bacteria: azotobacter chroococcum, arthrobacter globiformis, a. citreus and bacillus megaterium was studied. the following minimum concentrations were inhibitory in vitro: arthrobacter citreus--20 mug/ml., bacillus megaterium--40 mug/ml., azotobacter chroococcum--40 mug/ml. arthrobacter globiformis--70 mug/ml. cells of all microorganisms studied grown in the presence of dicumarol developed aberrant morphological forms.197659533
involvement of lipids in the break of the arrhenius plot of azotobacter nitrogenase. 197664170
specific lipid requirement for the activation of azotobacter nitrogenase [proceedings]. 197771102
bacterial polysaccharide which binds rhizobium trifolii to clover root hairs.immunofluorescence, quantitative immunoprecipitation, and inhibition of bacterial agglutination and passive hemagglutination indicate that cross-reactive antigenic determinants are present on the surface of rhizobium trifolii and clover roots. these determinants are immunochemically unique to this rhizobium-legume cross-inoculation group. the multivalent lectin trifoliin and antibody to the clover root antigenic determinants bind competitively to two acidic heteropolysaccharides isolated from ca ...197986535
molybdenum independence of nitrogenase component synthesis in the non-heterocystous cyanobacterium plectonema.the cyanobacterium plectonema boryanum (iu 594-utex 594) fixes n2 only in the absence of combined n and of o2. we induced nitrogenase by transfer to anaerobic n-free medium and studied the effect of mo starvation on nitrogenase activity and synthesis. activity was first detected within 3 h after transfer by the acetylene reduction assay in controls, increasing for at least 25 h. cells grown on nitrate and mo and then transferred to n-free, mo-free medium produced 8% of the control nitrogenase ac ...197896092
preparation of nitrogenase. 1978101737
purification and properties of nitrogenase from the cyanobacterium, anabaena cylindrica.the nitrogenase complex was isolated from nitrogen-starved cultures of anabaema cylindrica. sodium dithionite, photochemically reduced ferredoxin, and nadph were found to be effective election donors to nitro genase in crude extracts whereas hydrogen and pyruvate were not. the km for acetylene in vivo is ten-fold higher than the km in vitro, whereas this pattern does not hold for the non-heterocystous cyanobacterium, plectonema boryanum. this indicates that at least one mechanism of oxygen prote ...1979111934
a quantitative assay for bacterial rna polymerases. 1979114520
immunological studies with nitrogenase from azotobacter and bacterial nitrate reductases. 1979115328
respiration-coupled calcium transport by membrane vesicles from azotobacter vinelandii.membrane vesicles, isolated from osmotic lysates of azotobacter vinelandii spheroplasts in tris-acetate buffer, rapidly accumulate calcium in the presence of an oxidizable substrate. the addition of d-lactate to vesicles increases the rate of calcium uptake by 34-fold; l-malate, nadh, nadph, and reduced phenazine methosulfate are nearly as effective as lactate. the intravesicular calcium pool which accumulates under these conditions is rapidly discharged by isotopic exchange or in the presence o ...1978116111
[influence of lead on the microflora of the soil].in the soil, bacteria are not inhibited by lead. in vitro great sensibility of bacteria and resistance phenomena of gram plus bacteria are showed. lead is attracted by clay-humic complexes and becomes unavailable for microorganisms.1976134807
[effect of fertilizers on the number of bacteria involved in the turnover of nitrogen in pond water of the astrakhan region].the type of intensification affects the distribution of bacteria involved in turnover of nitrogen in pond water. green fertilizers (reed) stimulate the number of nitrogen-fixing bacteria, and the number and activity of nitrifying bacteria, to a higher degree than nitrogen and phosphorus fertilizers. reed is recommended as the main means for intensification of spawning ponds of the astrakhan region.1976137355
bacterial respiration. 1977140652
isolation of membrane vesicles with inverted topology by osmotic lysis of azotobacter vinelandii spheroplasts.membrane vesicles were prepared from azotobacter vinelandii spheroplasts by lysis in either potassium phosphate (ph 7.0) or tris1-acetate (ph 7.8) buffers. these 2 types of preparations differ considerably in their properties: 1) examination by scanning electron microscopy reveals that the pi vesicles consist primarily of closed structures 0.6-0.8 micrometer in diameter with a rough or particulate surface similar to that of spheroplasts. the tris vesicles are significantly smaller, 0.1-0.3 micro ...1977145514
molybdenum cofactors from molybdoenzymes and in vitro reconstitution of nitrogenase and nitrate reductase.a molybdenum cofactor (mo-co) from xanthine oxidase (xanthine:oxygen oxidoreductase, ec can be isolated from the enzyme by a technique that has been used to isolate an iron-molybdenum cofactor (femo-co) from component i of nitrogenase. n-methylformamide is used for the extraction of these molybdenum cofactors. mo-co from xanthine oxidase activates nitrate reductase (nadph:nitrate oxidoreductase, ec in an extract from neurospora crassa mutant strain nit-1; however, femo-co is un ...1977146198
the nitrogen-fixing complex of bacteria. 1975164247
bacterial terminal oxidases. 1975166799
nitrogenase. viii. mössbauer and epr spectroscopy. the mofe protein component from azotobacter vinelandii op.we have studied the molybdenum-iron protein (mofe protein, also known as component i) from azobacter vinelandi using mössbauer spectroscopy and electron paramagnetic resonance on samples enriched with 57fe. these spectra can be interpreted in terms of two epr active centers, each of which is reducible by one electron. a total of four different chemical environments of fe can be discerned. one of them is a cluster of fe atoms with a net electronic spin of 3/2, one of them is high-spin ferrous iro ...1975167863
high and low reduction potential 4fe-4s clusters in azotobacter vinelandii (4fe-4s) 2ferredoxin i. influence of the polypeptide on the reduction potentials.azotobacter vinelandii (4fe-4s)2 ferredoxin i (fd i) is an electron transfer protein with mr equals 14,500 and eo equals -420 mv. it exhibits and epr signal of g equals 2.01 in its isolated form. this resonance is almost identical with the signal that originates from a "super-oxidized" state of the 4fe-4s cluster of potassium ferricyanide-treated clostridium ferredoxin. a cluster that exhibits this epr signal at g equals 2.01 is in the same formal oxidation state as the cluster in oxidized chrom ...1975170272
the pyruvate-dehydrogenase complex from azotobacter vinelandii. 3. stoichiometry and function of the individual components.labelling studies with n-ethylmaleimide show that either in the presence of mg2+, thiamine pyrophosphate (tpp) and pyruvate or in the presence of nadh the overall activity of the pyruvate dehydrogenase complex from azotobacter vinelandii is inhibited without much inhibition of the partial reactions. the complex undergoes a conformational change upon incubation with nadh. the inhibition by bromopyruvate is less specific. specific incorporation of a fluorescent maleimide derivative was observed on ...1975173536
nitrogenase from azotobacter chroococcum. purification and properties of the component proteins.1. a large-scale purification of the nitrogenase components from azotobacter chroococcum yielded two non-haem iron proteins, both of which were necessary for nitrogenase activity and each had a specific activity of approximately 2000 +/- 300 nmol of acetylene reduced/mg protein per min in the presence of sautrating amounts of the other. this procedure freed the mo-fe protein from a protein contaminant which had an electron paramagnetic resonance signal at g = 1.94. 2. both proteins were purified ...1975173545
tetramethyl-p-phenylenediamine oxidase reaction in azotobacter was possible to quantitate the tetramethyl-p-phenylenediamine (tmpd) oxidase reaction in azotobacter vinelandii strain o using turbidimetrically standarized resting cell suspensions. the q(o2) value obtained for whole cell oxidation of ascorbate-tmpd appeared to reflect the full measure of the high respiratory oxidative capability usually exhibited by this genera of organisms. the q(o2) value for the tmpd oxidase reaction ranged from 1,700 to 2,000 and this value was equivalent to that obtain ...1975174491
control of transformation competence in azotobacter vinelandii by nitrogen catabolite derepression.azotobacter vinelandii (atcc 12837) became competent to be transformed by exogenous deoxyribonucleic acid towards the end of exponential growth. competence in wild-type and nitrogenase auxotrophic (nif-) strains was repressed by the addition of ammonium salts or urea to the transformation medium. transformation of wild-type cells and nif- strains was optimal on nitrogen-free or nitrogen-limiting medium, respectively. transformation of wild-type cells also was enhanced when the transformation med ...1976176141
[azotobacter chroococcum hydrogenase reduction of certain acceptors and kinetic parameters of the studied reactions]. 1975176559
[study of the nitrogenase from azotobacter vinelandii by the method of spin labels].the interaction of nitrogenase with spin labels of four types have been studied. conclusion about the presence of two sh-groups in the nitrogenase active site (one in mo-fe-protein and one in the fe-protein) have been drawn from the correlation between the degree of inhibition of nitrogenfixing activity by the labels derived from p-cl-hg-benzoate and degree of binding of these labels to the nitrogenase molecule. anaysis of epr spectra of spin-labeled nitrogenase at 77 degrees k and at room tempe ...1975176570
the biosynthesis of alginic acid by azotobacter vinelandii.the sequence of reactions by which alginic acid is biosynthesized from sucrose in azotobacter vinelandii was determined both by feeding radioactive individual enzymes involved. results indicate that the first polymeric substance formed in the synthesis is polymannuronic acid and that mannuronic acid units are epimerized to guluronic acid at the polymer level. guluronic acid does not appear to be formed at the monomer level, either free or in combination with gdp.1975179528
nitrogenase of azotobacter chroococcum: inhibition of adp of the reduction of oxidised fe protein by sodium dithionite. 1975179869
nitrogenase of azotobacter chroococcum. kinetics of the reduction of oxidized iron-protein by sodium dithionite.the kinetics of the reduction of oxidized fe-protein of nitrogenase from azotobacter chroococcum by sodium dithionite were studied by stopped-flow and rapid-freezing e.p.r. (electron-paramagnetic-resonance) spectroscopy. the appearance of the gav. = 1.94 e.p.r. signal (0.24 electron integrated intensity/mol) was associated with a one-electron reduction by so2--with k greater than 10(8)m-1-s-1 at 23 degrees c. a value of k = 1.75s-1 was obtained for the rate of dissociation of s2o42- into 2so2-- ...1976180978
purification and properties of paramagnetic protein from clostridium pasteurianum w5.the purification to homogeneity of the non-heme iron protein, sometimes referred to as either "red protein" or "paramagnetic protein", from clostridium pasteurianum w5 extracts is described and its physicochemical properties studied. this paramagnetic protein (g= 1.94) has a molecular weight of about 25000 and contains two iron and two acid-labile sulfur atoms per mol of protein. its midpoint potential at ph 7.5, as determined by electron paramagnetic resonance titration, is -300 mv. optical cir ...1976181066
effects of pure paraquat dichloride, "gramoxone w", and formulation additives on soil microbiological activities. 3. estimations of soil microflora and enzyme activity in field-treated soil. 1976185843
nitrogenase of azotobacter chroococcum: a new electron-paramagnetic-resonance signal associated with a transient species of the mo-fe protein during catalysis. 1976187450
characterization of a membrane-bound nitrate reductase from azotobacter chroococcum. 1977193497
regulation of nitrogen fixation by fe-s protein ii in azotobacter vinelandii. 1977196854
the response of azotobacter chroococcum to oxygen: superoxide-mediated effects.nitrogenase in azotobacter chroococcum whole cells was inhibited by enzymically generated superoxide anion (o2-), hydrogen peroxide, and ethyl hydrogen peroxide. the degree of inhibition produced by o2- was related to the quantity of oxygen supplied to the organisms in continuous cultures. o2- also inhibited oxygen uptake by whole cells. these o2- mediated inhibitions were prevented by bovine superoxide dismutase. the quantities of superoxide dismutase (sod), and catalase associated with cells g ...1977200330
purification and characterization of cytochrome o from azotobacter vinelandii.the membrane-bound cytochrome o has been solubilized from the azotobacter vinelandii electron transport particle and further purified by use of conventional chromatographic procedures. the spectral characteristics as well as the other properties noted for purified cytochrome o are reported herein.1978207321
atp synthetase associated with the nitrogenase of azotobacter vinelandii. 1978208576
flavin affinity chromatography: general methods for purification of proteins that bind riboflavin. 1978212963
nitrogenase x: mössbauer and epr studies on reversibly oxidized mofe protein from azotobacter vinelandii op. nature of the iron centers.under anaerobic conditions the molybdenum-iron protein (mofe protein) from azotobacter vinelandii can be reversibly oxidized with thionine. electron paramagnetic resonance studies reveal that the oxidation proceeds in two distinct phases: the mofe protein can be oxidized by four electrons without loss of the epr signal from the s = 3/2 cofactor centers. a second oxidation step, involving two electrons, leads to the disappearance of the cofactor epr signal. in order to correlate the events during ...1978215215
preliminary crystallographic data for azotobacter cytochrome c5. 1978216808
synthesis of a new 8-spin-labeled analog of adenosine 5'-phosphate and its interaction with amp nucleosidase.the synthesis of a new 8-spin-labeled analog of amp, 8-[[[(2,2,5,5-tetramethyl-1-oxy-3-pyrrolidinyl)carbamoyl]methyl]thio]adenosine 5'-phosphate (8-slamp), is described. the procedure is facile and results in high yields. 8-slamp is a competitive inhibitor of amp nucleosidase with a ki of 19 microm as compared to a km of 100 microm for amp. the analog is not a substrate for the enzyme and does not displace mgatp2- from the allosteric sites under the usual assay conditions. the epr spectrum of th ...1979221493
on the efficiency of oxidative phosphorylation in membrane vesicles of azotobacter vinelandii and of rhizobium leguminosarum bacteroids. 1979223842
changes in the epr signal of dinitrogenase from azotobacter vinelandii during the lag period before hydrogen evolution begins.during the lag period before h2 is evolved by the nitrogenase system, the epr signal of dinitrogenase decreases steadily, indicating transfer of electrons into dinitrogenase. the rate constant for the decrease in amplitude of the epr signal, the steady state rate of h2 evolution from nitrogenase, and the length of the lag period have been measured. the data suggest that h2 is evolved only after dinitrogenase has been reduced by 2 electrons/molybdenum. the electrons that have been transfered into ...1979227860
rate-limiting step in oxidation of physiological and artificial reductants by azotobacter vinelandii membrane vesicles. 1979228601
iron-sulfur clusters in the molybdenum-iron protein component of nitrogenase. electron paramagnetic resonance of the carbon monoxide inhibited state.carbon monoxide inhibits reduction of dinitrogen (n2) by purified nitrogenase from azotobacter vinelandii and clostridium pasteurianum in a noncompetitive manner (kii and kis = 1.4 x 10(-4) and 4.5 x 10(-4) and 7 x 10(-4) atm and 14 x 10(-4) atm for the two enzymes, respectively). the onset of inhibition is within the turnover time of the enzyme, and co does not affect the electron flux to the h2-evolving site. the kinetics of co inhibition of n2 reduction are simple, but co inhibition of acetyl ...1979228701
relationship between calcium and uroinic acids in the encystment of azotobacter vinelandii.encystment of azotobacter vinelandii (atcc 12837) in modified burk nitrogen-free medium (ph 7.0) containing 0.2 percent beta-hydroxybutyrate occurs optimally in 0.37 to 0.44 mm solutions of calcium ions. suspension of cells in media deficient in calcium results in abortive encystment characterized by the release of viscous cyst coat material. mature cysts rupture in ethylene glycol-bis-(beta-aminoethyl ether)-n,n'-tetraacetic acid, suggesting that calcium is a structural component of the cyst co ...1975235508
ammonium uptake by nitrogen fixing bacteria i. azotobacter vinelandii.both the changes in the activities of nitrogenase, glutamine synthetase and glutamate dehydrogenase and in the extracellular and intracellular nh4+ concentrations were investigated during the transition from an nh4+ free medium to one containing nh4+ ions for a continuous culture of azotobacter vinelandii. if added in amounts causing 80-100% repression of nitrogenase, ammonium acetate, lactate and phosphate are absorbed completely, whereas chloride, sulfate and citrate are only taken up to about ...1975239660
on the role of sulfhydryl groups in the structure and function of the azotobacter vinelandii rna polymerase.exposure of sulfhydryl groups as indicated by titration kinetics is decreased under conditions where rna polymerase exists as a dimer or higher aggregate (low salt), in the presence of mn2+, or when bound to d(a-t). incubation of phenylmercurisulfonate with rna polymerase above ph 9.0 results in loss of d(a-t) binding ability. poly(u) binding is more sensitive to sulfhydryl modification and is lost as ph's above 8.0. the presence of 4 mm mn2+ has an obvious effect in stabilizing the polymerase-p ...1975240405
microbial metabolism of a parathion-xylene pesticide formulation.a mixed bacterial culture was adapted to growth on a mixed carbon substrate consisting of the pesticide parathion and its xylene-based formulation. the environmental growth parameters of temperature, ph, and dissolved oxygen concentration were optimized to obtain complete metabolism of parathion from this mixed carbon substrate. this adapted culture grew rapidly (mu = 0.7 per h) on the pesticide formulation at high parathion suspensions (3,000 mg/liter). carbon utilization from this mixed subst ...1975242255
transposition of plasmid dna segments specifying hydrocarbon degradation and their expression in various microorganisms.the conjugative tol plasmid (75 mdal), specifying biodegradation of xylenes, toluene, and trimethylbenzene derivatives, undergoes dissociation in pseudomonas aeruginosa pao to a nonconjugative tol(*) plasmid (28 mdal) and a transfer plasmid termed toldelta (48 mdal). the tol(*) plasmid is rendered transmissible through introduction of a number of conjugative plasmids such as factor k, cam, and toldelta but not by the fp2 derivative pr0271. transfer of tol(*) via factor k or toldelta is mediated ...1978277912
[microbiology of cultivated soils in the semiarid zone of argentina i. wheat]. 1977279058
covalently bound non-coenzyme phosphorus residues in flavoproteins: 31p nuclear magnetic resonance studies of azotobacter addition to the 5'-phosphate ester on its flavin mononucleotide (fmn) moiety, flavodoxin from azotobacter vinelandii contains 2 moles of tightly bound phosphate. one non-coenzyme phosphate group is covalently bound to the protein, as it remains with the protein on acid precipitation, whereas the other phosphate is released. the invariance of the (31)p nuclear magnetic resonance chemical shift of the covalently bound phosphate (-0.8 ppm relative to 85% phosphoric acid) with ph, even in the pre ...1979291038
identification of iron-sulfur centers in the iron-molybdenum proteins of nitrogenase.the core extrusion method has been applied to the determination of the type ([2fe-2s], [4fe-4s]) and number of iron-sulfur centers in the femo proteins of the nitrogenases from clostridium pasteurianum and azotobacter vinelandii. the method involves extrusion with o-xylyl-alpha, alpha'-dithiol, ligand exchange of the extrusion products with p-cf3c6h4sh (rfsh), and identification and quantitation of the resultant [fensn(srf)4]2- complexes (n = 2,4) by 19f nmr spectroscopy. in hexamethylphosphoram ...1979291915
choice of liquid, semisolid, or soil suspension media: an important factor modifying the effect of pesticides on the nitrogenase (c2h2) activity of clostridium pasteurianum, azotobacter chroococcum, and spirillum lipoferum beijerinck. 1979295269
genetic analysis of azotobacter vinelandii mutant strains unable to fix nitrogen.transformation was used to perform ratio test crosses with mutant strains of azotobacter vinelandii unable to fix n2. mutations that simultaneously eliminated both components of nitrogenase (nif-1 and nif-2) were tightly linked. the nif-45 mutation that resulted in the absence of an active molybdenum cofactor was closer to nif-1 and nif-2 than to any of the other nif mutations. strains that lacked component i carried mutations that were closely linked to each other. mutations that probably were ...1977299457
application of the fluorescent antibody technique to the study of an isolate of beijerinckia in soil.fluorescent antibody was prepared against a temperate-soil isolate of beijerinckia obtained from a rhizosphere of rice growing in camargue (france). the antibody did not cross-react with any of 6 species of azotobacter, 4 species of beijerinckia, or 44 unidentified soil bacteria isolated from a spectrum of rhizospheres, but strongly stained the homologous beijerinckia isolate. the isolate grew well in autoclave camargue soil, but increased in numbers only slightly in nonsterile soil during 9 day ...1977319880
atp analogues as initiation and elongation nucleotides for bacterial dna-dependent rna polymerase. 1977328048
determination of the chain stoichiometries from the number of reactive sulfhydryl groups in the pyruvate dehydrogenase complexes of azotobacter vinelandii and escherichia coli. 1977340223
microbial society and its activity in the this study, with the help of the buried slide method, a qualitative observation of the microsociological association in the soil was assessed. fungal mycelium cohabiting with bacterial forms, rods as well as cocci, individual colonies of azotobacter-type cells, and certain algae of hantzschia species were recorded in a central european typical garden soil. the use of cholodny-strugger combination method was helpful in ascertaining the decaying nature of a soil nematode and also fungal myceliu ...1977345684
fluorescence energy-transfer studies on the pyruvate dehydrogenase complex isolated from azotobacter vinelandii.fluorescence energy transfer has been employed to estimate the minimum distance between each of the active sites of the 4 component enzymes of the pyruvate dehydrogenase multienzyme complex from azotobacter vinelandii. no energy transfer was seen between thiochrome diphosphate, bound to the pyruvate decarboxylase active site, and the fad of the lipoamide dehydrogenase active site. likewise, several fluorescent sulfhydryl labels, which were specifically bound to the lipoyl moiety of lipoyl transa ...1978348464
adenosine monophosphate nucleosidase from azotobacter vinelandii and escherichia coli. 1978357895
iron storage in bacteria. 1979377091
characterization of azotobacter vinelandii deoxyribonucleic acid and folded chromosomes.the properties of azotobacter vinelandii deoxyribonucleic acid (dna) and folded chromosomes were studied and compared to those of escherichia coli as a standard. based on melting temperature and buoyant density measurements, the guanosine + cytosine content of purified a. vinelandii dna was 65%, whereas that of e. coli dna was 50%. the results of renaturation studies showed that the unique dna sequence lengths of the two organisms were similar with cot1/2 values of 7.3 +/- 0.4 mol.s/liter and 7. ...1979378943
circular dichroism and magnetic circular dichroism of nitrogenase proteins.circular dichroism (cd) and magnetic circular dichroism (mcd) spectra of nitrogenase components (mofe protein and fe protein) from azotobacter vinelandii (av) and klebsiella pneumoniae (kp) have been obtained in the near infrared-visible-near ultraviolet spectral region. previously, visible cd was reported to be absent or barely detectable in nitrogenase proteins; mcd spectra have not been reported. the chiroptical spectra can be measured in solution at room temperature, an advantage relative to ...1979379860
crosslinking studies with the pyruvate dehydrogenase complexes from azotobacter vinelandii and escherichia coli. 1979380991
comparative surfact structure of 16s ribosomal ribonucleic acid of 30s ribosomes of procaryotic cells.ribonuclease t(1) treatment of 30s ribosomes of escherichia coli converts a large region at the 3' oh end of 16s ribosomal ribonucleic acid (rrna) to low-molecular-weight rna. the final 25 nucleotides at the 3' terminus of the molecule emerge relatively intact, whereas most of the region "upstream," for about 150 nucleotides, is converted to oligonucleotides. identical enzyme treatment generates a fragment of about 60 nucleotides from the middle of 16s rrna (section d'). to determine whether the ...1979387717
microbiological examination of some sudanese soils.the composition of the microflora in different layers of four representative oil profiles of sudan were studied. counts of all types of microorganisms decreased significantly with depth in soil. azotobacter, in particular, occurred in high densities; representative strains were isolated and studied for their different characteristics. beijerinckia was detected as well, and a new method for the estimation of their numbers in pure cultures, based on the overlay agar technique, is described.1979398646
glucan common to the microcyst walls of cyst-forming bacteria.chemical analysis indicated that d-glucose is tha major neutral monosaccharide present in the microcysts of a range of gram-negative bacteria. varying amounts of other neutral sugars were found. the glucose was mainly present as a glucan that could be extracted from microcysts of representative strains with alkali or mild acid treatment. the glucan could be identified as an alpha-1,3-linked polymer on the basis of (i) periodate resistance of the extracted polymer and the material present in micr ...1977402353
amino acid sequence of desulfovibrio vulgaris flavodoxin.the complete amino acid sequence for the 148-amino acid flavodoxin from desulfovibrio vulgaris was determined to be: h3n+-met-pro-lys-ala-leu-ile-val-tyr-gly-ser-thr-thr-gly-asn-thr-glu-tyr-thr-ala-glu-thr-ile-ala-arg-glu-leu-ala-asn-ala-gly-tyr-glu-val-asp-ser-arg-asp-ala-ala-ser-val-glu-ala-gly-gly-leu-phe-glu-gly-phe-asp-leu-val-leu-leu-gly-cys-ser-thr-trp-gly-asp-asp-ser-ile-glu-leu-gln-asp-asp-phe-ile-pro-leu-phe-asp-ser-leu-glu-glu-thr-gly-ala-gln-gly-arg-lys-val-ala-cys-phe-gly-cys-gly-as ...1977402366
isolation of an iron-molybdenum cofactor from nitrogenase.a method for the isolation of an iron-molybdenum cofactor (femoco) from component i of nitrogenase is described. this method is used to isolate femoco from aerobic, anaerobic, facultative, and photosynthetic nitrogen-fixing organisms. the fe/mo ratio in the femoco from azotobacter vinelandii and clostridium pasteurianum is 8:1. the femoco contains six atoms of acid-labile sulfide per eight fe atoms. crystalline component i from a. vinelandii contains 2 mo, 33 fe, and 27 acid-labile sulfide atoms ...1977410019
effects of long-term treatment with acetylene on nitrogen-fixing microorganisms.long periods of experimental incubation with acetylene led to a multifold enhancement of acetylene-reducing activity in anabaena cylindrica, anabaenopsis circularis, rhodospirillum rubrum, and azotobacter vinelandii. rates of acetylene reduction showed a gradual increase and reached a peak after 2 to 6 h of continuous incubation under acetylene. thereafter, enzyme activity rapidly declined. a similar enhancement of ethylene production was observed when pretreatment with acetylene was interrupted ...1977413480
nitrogenase activity of immobilized azotobacter part of a program to investigate the use of biological nitrogen fixation for fertilizer ammonia production, an investigation into the immobilization of the aerobic, nitrogen-fixing bacterium, azotobacter vinelandii was undertaken. immobilization was acaccomplished by adsorption onto an anionic exchange cellulose (cellex e) with loadings as high as 10'' cells/g resin. immobilized cell preparations were tested under both batch and continuous-flow conditions. nitrogenase activities as high as 42 ...1979427263
Displaying items 1 - 100 of 3186