| characterization studies on the membrane-bound adenosine triphosphatase (atpase) of azotobacter vinelandii. | the adenosinetriphosphatase (atpase) (ec 3.6.1.3) 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 ... | 1975 | 141 |
| 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 ... | 1975 | 1251 |
| 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 ... | 1976 | 3492 |
| 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 ... | 1976 | 4324 |
| 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 ... | 1976 | 4579 |
| 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 ... | 1976 | 9392 |
| 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 ... | 1977 | 13144 |
| studies on the priming specificity of polyribonucleotides on azotobacter vinelandii polynucleotide phosphorylase. | | 1977 | 18453 |
| 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 ... | 1977 | 20943 |
| adenylosuccinate synthetase from azotobacter vinelandii: purification, properties and steady-state kinetics. | | 1977 | 21629 |
| proton-coupled sodium uptake by membrane vesicles from azotobacter vinelandii. | | 1978 | 25893 |
| the glutamine synthetase from azotobacter vinelandii: purification, characterization, regulation and localization. | the glutamine synthetase (ec 6.3.1.2) 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 ... | 1978 | 29757 |
| 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. ... | 1978 | 30448 |
| inosine nucleosidase from azotobacter vinelandii. purification and properties. | an 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 ... | 1978 | 31149 |
| purification and properties of azotobacter vinelandii glutamine synthetase. | | 1979 | 35099 |
| 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 6.3.1.2) 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 ... | 1979 | 39606 |
| 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 ... | 1979 | 39756 |
| proceedings: pressure and temperature dependence of the cooperative interactions in azotobacter vinelandii nitrogenase. | | 1975 | 50813 |
| 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 ... | 1979 | 86535 |
| 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 ... | 1978 | 96092 |
| 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 ... | 1979 | 111934 |
| 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 ... | 1978 | 116111 |
| 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 ... | 1977 | 145514 |
| 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 1.2.3.2) 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 1.6.6.2) in an extract from neurospora crassa mutant strain nit-1; however, femo-co is un ... | 1977 | 146198 |
| 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 ... | 1975 | 167863 |
| 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 ... | 1975 | 170272 |
| 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 ... | 1975 | 173536 |
| tetramethyl-p-phenylenediamine oxidase reaction in azotobacter vinelandii. | it 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 ... | 1975 | 174491 |
| 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 ... | 1976 | 176141 |
| [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 ... | 1975 | 176570 |
| 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. | 1975 | 179528 |
| regulation of nitrogen fixation by fe-s protein ii in azotobacter vinelandii. | | 1977 | 196854 |
| 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. | 1978 | 207321 |
| atp synthetase associated with the nitrogenase of azotobacter vinelandii. | | 1978 | 208576 |
| 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 ... | 1978 | 215215 |
| on the efficiency of oxidative phosphorylation in membrane vesicles of azotobacter vinelandii and of rhizobium leguminosarum bacteroids. | | 1979 | 223842 |
| 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 ... | 1979 | 227860 |
| rate-limiting step in oxidation of physiological and artificial reductants by azotobacter vinelandii membrane vesicles. | | 1979 | 228601 |
| 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 ... | 1979 | 228701 |
| 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 ... | 1975 | 235508 |
| 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 ... | 1975 | 239660 |
| 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 ... | 1975 | 240405 |
| 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 ... | 1978 | 277912 |
| covalently bound non-coenzyme phosphorus residues in flavoproteins: 31p nuclear magnetic resonance studies of azotobacter flavodoxin. | in 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 ... | 1979 | 291038 |
| 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 ... | 1979 | 291915 |
| 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 ... | 1977 | 299457 |
| determination of the chain stoichiometries from the number of reactive sulfhydryl groups in the pyruvate dehydrogenase complexes of azotobacter vinelandii and escherichia coli. | | 1977 | 340223 |
| 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 ... | 1978 | 348464 |
| adenosine monophosphate nucleosidase from azotobacter vinelandii and escherichia coli. | | 1978 | 357895 |
| 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. ... | 1979 | 378943 |
| 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 ... | 1979 | 379860 |
| crosslinking studies with the pyruvate dehydrogenase complexes from azotobacter vinelandii and escherichia coli. | | 1979 | 380991 |
| 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 ... | 1979 | 387717 |
| 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 ... | 1977 | 410019 |
| 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 ... | 1977 | 413480 |
| nitrogenase activity of immobilized azotobacter vinelandii. | as 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 ... | 1979 | 427263 |
| regulation of arginine biosynthesis in azotobacter vinelandii nq [proceedings]. | | 1979 | 428667 |
| two crystal forms of azotobacter ferredoxin. | two crystal forms of azotobacter vinelandii (4fe-4s)2 ferredoxin i (fd i) have been grown which are suitable for high resolution x-ray diffraction studies. tetragonal crystals grow as square bipyramids from ammonium sulfate and tris buffer using a temperature gradient. the space group is p41212 (or p43212) with a = 55.3, c = 95.9 a and 1 molecule/asymmetric unit. triclinic crystals grow as plates or laths from ammonium sulfate and phosphate buffer at constant temperature. the space group is p1 w ... | 1979 | 429371 |
| fatty acids in phospholipids of cells, cysts, and germinating cysts of azotobacter vinelandii. | cyclopropane fatty acids constitute 25% of the phospholipid acyl groups in cysts of azotobacter vinelandii. these are lost by dilution during germination when the synthesis of the fatty acids characteristic of vegetative cell phospholipids commences. | 1979 | 438125 |
| polyamines as activators of amp nucleosidase from azotobacter vinelandii. | polyamines at physiological concentrations activate amp nucleosidase from azotobacter vinelandii. biological significance of the activation is discussed in relation to the control of adenylate energy charge and the purine nucleotide synthesis in prokaryotes. | 1979 | 446646 |
| 5-n-alkylresorcinols from encysting azotobacter vinelandii: isolation and characterization. | azotobacter vinelandii was found to form novel lipid compounds when encystment was initiated by 0.2% beta-hydroxybutyrate. an examination of these compounds led to the isolation and characterization of 5-n-heneicosylresorcinol, 5-n-tricosylresorcinol, and their galactoside derivatives. | 1979 | 457611 |
| phosphate-limited culture of azotobacter vinelandii. | batch cultures of azotobacter vinelandii grown in phosphate-deficient media were compared with control cultures grown in phosphate-sufficient media. phosphate limitation was assessed by total cell yield and by growth kinetics. although cell protein, nucleic acids, and early growth rate were unaffected by phosphate deficiency, cell wall structure, oxygen uptake, and cell viability were significantly affected. also, phosphate-limited cells contained much larger amounts of poly-beta-hydroxybutyric ... | 1979 | 457614 |
| isolation and properties of a glycohydrolase specific for nicotinamide mononucleotide from azotobacter vinelandii. | a glycohydrolase that catalyzes the irreversible conversion of nmn to nicotinamide and ribose 5-phosphate has been partially purified from a sonic extract of azotobacter vinelandii. the enzyme is highly specific for nmn. nad, nadp, nicotinic acid-adenine dinucleotide, nicotinamide riboside and alpha-nmn are not significantly hydrolyzed by this enzyme, nor do they compete with nmn. the enzyme also exhibits an absolute dependence on guanylic acid derivatives with following order of relative effect ... | 1979 | 457634 |
| optimal conditions for transformation of azotobacter vinelandii. | optimal transformation of azotobacter vinelandii op required a 20-min incubation of the competent cells with deoxyribonucleic acid at 30 degrees c in buffer (ph 6.0 to 8.0) containing 8 mm magnesium sulfate. nitrogen-fixing transformants of nitrogen fixation-deficient recipients could be plated immediately on selective medium, but transformants acquiring rifampin and streptomycin resistance required preincubation in nonselective medium. the three phenotypes achieved an approximately equal and st ... | 1979 | 479104 |
| effects of monovalent cations on amp nucleosidase from azotobacter vinelandii. | the effect of monovalent cations on the purified amp nucleosidase (amp phosphoribohydrolase, ec 3.2.2.4) from azotobacter vinelandii was investigated. all the monovalent cations were activators of the enzyme: rb+ and cs+ were the most effective, followed by k+, na+, nh4+ and li+ in that order. the apparent ka for mgatp and nh values (hill's interaction coefficient) decreased from 0.9 to 0.1 mm, and from 4 to 1, respectively, with the increase in k+ concentration, suggesting that the cation effec ... | 1979 | 486499 |
| respiratory-chain characteristics of mutants of azotobacter vinelandii negative to tetramethyl-p-phenylenediamine oxidase. | | 1979 | 488089 |
| the oxidation-reduction potentials of cytochrome o + c4 and cytochrome o purified from azotobacter vinelandii. | oxidation-reduction titrations of azotobacter vinelandii cytochrome o + c4 and cytochrome o were performed with simultaneous potential and absorbance measurements under anaerobic conditions. cytochrome c4 has a midpoint potential (em, 7.4) of 260mv and purified cytochrome o has an em, 7.4 of -18mv. little change in the midpoint potential of cytochrome o was observed when titrated in the ph range 6.2--9.8. | 1979 | 518554 |
| [transformation of the herbicide 2,4-d in an azotobacter culture]. | transformation of the herbicide 2,4-d[14c] was studied in the cultures of azotobacter chroococcum, azotobacter vinelandii and azotobacter agile. these cultures assimilated 2,4-d and metabolized it. the products of transformation included phenol derivatives, water-soluble products, and carbon dioxide. about 15% of the herbicide taken up by the cells was bound to protein. | 1979 | 530139 |
| a preliminary crystallographic study of isocitrate dehydrogenase from azotobacter vinelandii. | | 1977 | 592382 |
| transformation of azotobacter vinelandii strains unable to fix nitrogen with rhizobium spp. dna. | the phenotypes of azotobacter vinelandii atcc 12837 strains defective in nitrogen fixation (nif-) were characterized by intrageneric transformation with known nif- strains of a. vinelandii op. these former mutant strains were used as recipients for intergeneric transformation by deoxyribonucleic acid (dna) prepared from rhizobium spp. to determine if the rhizobia would transform the azotobacter nif- phenotypes to nif+. the frequency of nif+ transformants using rhizobium dna was always less than ... | 1978 | 647476 |
| isolation and partial characterization of two different subunits from the molybdenum-iron protein of azotobacter vinelandii nitrogenase. | the molybdenum-iron protein of azotobacter vinelandii nitrogenase was separated into two subunits of equal concentration by ion exchange chromatography on sulfopropyl (sp) sephadex at ph 5.4 in 7 m urea. better than 90% yield of each subunit was obtained on a preparative scale if the reduced carboxymethylated molybdenum-iron protein was incubated at 45 degrees c for 45 min prior to chromatography. without the heating step low yields of the subunits were obtained. although the amino acid composit ... | 1978 | 649581 |
| transfer from rhizobium japonicum to azotobacter vinelandii of genes required for nodulation. | a mutant strain of azotobacter vinelandii that is unable to fix n2 (nif-) was transformed to nif+ with dna from rhizobium japonicum. of 50 nif+ transformants tested, 3 contained the o antigen-related polysaccharide that is present on the cell surface of a nodulating r. japonicum strain, but is absent from a non-nodulating mutant strain. | 1978 | 659367 |
| studies on the red oxidase (cytochrome o) of azotobacter vinelandii. | | 1978 | 666783 |
| membrane energization in relation with nitrogen fixation in azotobacter vinelandii and rhizobium leguminosarum bacteroids. | nitrogen fixation in a. vinelandii and r. leguminosarum bacteroides shows identical characteristics with respect to the dependence on membrane energization, the sensitivity to uncouplers, the atp/adp-ratio, and the dependences on flavodoxinhydroquinone as electrondonor. although we have been successful in preparing inside-out vesicles which can be energized, attempts to couple these membranes to n2-ase were still unsuccessful. one of the major problems could be the failure to energize these vesi ... | 1978 | 667180 |
| involvement of the cytoplasmic membrane in nitrogen fixation by rhizobium leguminosarum bacteroids. | 1. the nitrogen-fixing efficiency of freshly prepared suspensions of rhizobium leguminosarum bacteroids from pea root nodules was considerably enhanced by addition of bovine serum albumin. evidence was found that during preparation of bacteroids the cell membrane is exposed to the uncoupling effect of free fatty acids and to plant phospholipase d activity. both effects could be counteracted by bovine serum albumin. 2. a technique was developed by which concentrations of free o2 and nitrogenase a ... | 1978 | 668685 |
| regulatory properties of the nitrogenase from rhodopseudomonas palustris. | ammonium salts, glutamine, asparagine, and urea cause an immediate inactivation (switch-off) of light-dependent acetylene reduction in intact cells of the photosynthetic bacterium rhodopseudomonas palustris. this effect is reversible showing the same kinetic pattern of inactivation and reactivation with all effector compounds. its duration depends on the amount of effector added to the cells. both nitrogenase components are found catalytically active in a cell-free preparation after enzyme switc ... | 1978 | 678011 |
| ultrastructural and physiological changes occurring upon germination and outgrowth of azotobacter vinelandii cysts. | dormant cysts of azotobacter vinelandii germinated at 30 degrees c in burk nitrogen-free media containing 1% glucose. samples taken at intervals and examined by electron microscopy revealed that as germination progressed, vesicle-like and fibrillar structures became visible in the intine region. lamellae associated with the cell membrane appeared in the central body at 6 h post-initiation of germination. both electron micrographic and chemical analysis showed that the poly-beta-hydroxybutyrate c ... | 1978 | 681284 |
| the role of adenosine monophosphate nucleosidase in the regulation of adenine nucleotide levels in azotobacter vinelandii during aerobic-anaerobic transitions. | | 1978 | 708078 |
| kinetic studies on electron transfer and interaction between nitrogenase components from azotobacter vinelandii. | kinetic properties of electron transfer by nitrogenase of azotobacter vinelandii are dependent on the concentration of the two components of nitrogenase. an excess of the mofe protein inhibits electron transfer in a distinctive manner, and the inhibition is reversed by increasing levels of reductant. the saturation curve for fe protein is hyperbolic, indicating that only one fe protein molecule per mofe protein is required for full activity in atp hydrolysis and electron transfer. these results ... | 1978 | 708696 |
| potentiometric titration of the high- and low-potential 4fe-4s* centers of azotobacter vinelandii ferredoxin i. | the high-potential 4fe-4s* center ofazotobacter vinelandii ferredoxin i has been titrated potentiometrically by a reductive procedure. the absorbance decrease at 510 nm accompanying the reduction of the high-potential center titrated with an em of 320 mv (n = 1). the low-potential 4fe-4s* center was titrated by using the absorbance decrease at 410 nm to monitor its reduction. this center exhibited an em of -424 mv (n = 1). | 1978 | 711680 |
| nitrogenase: properties of the catalytically inactive complex between the azotobacter vinelandii mofe protein and the clostridium pasteurianum fe protein. | the catalytically inactive complex generated by the combination of the azotobacter vinelandii mofe protein (av1) and the clostridium pasteurianum fe protein (cp2) inhibits n2 reduction, c2h3 reduction, h+ reduction and atp hydrolysis catalyzed by the homologous nitrogenases. kinetic data indicate that the inactive complex consists of two molecules of cp2 to one molecule of av1, with values for the inhibitor constant in the range of 1--10 nm. inhibition of c. pasteurianum nitrogenase by av1 produ ... | 1978 | 728444 |
| induction of transformation competence in azotobacter vinelandii iron-limited cultures. | azotobacter vinelandii strains uw (nif+) or uw1 (nif-) were induced to form competent cells by growing cultures in burk medium without added iron. competent cells were generated in either liquid or solid medium. the competent culture was highly colored by the characteristic fluorescent green pigment of a. vinelandii but all pigmented cultures were not competent. in liquid culture, competent cells required a fixed nitrogen source (ammonia, nitrate, or urea) that was also a nitrogenase repressor. ... | 1978 | 747819 |
| nitrogenase xi: mössbauer studies on the cofactor centers of the mofe protein from azotobacter vinelandii op. | we have studied the mofe protein from azotobacter vinelandii op with mössbauer spectroscopy in applied magnetic fields up to 50 kg. the results are as follows. (1) the mössbauer spectra of the s = 3/2 centers, which reside on the cofactor of nitrogenase, have been decomposed into six subcomponents. this suggests that each center contains 5-7, most probably 6, fe atoms, thus confirming our earlier conclusions which were based on the quantitation of epr data and on the assumption that the mofe pro ... | 1979 | 760805 |
| kinetic studies of bacillus polymyxa nitrogenase. | nitrogenase from the facultative anaerobe bacillus polymxa was separated into its component proteins, which were recombined in the ratio that produced optimal specific activity (125 to 175 nmol of c2h2 reduced/min per mg of total protein). the apparent michaelis constants (km)for the magnesium adenosine triphosphate complex, reducible substrates azide, acetylene, and n2 and the nonphysiological electron donor hydrosulfite (s2o42-) were determined to be 0.7, 0.7, 0.2, 0.06, and 0.03 mm, respectiv ... | 1976 | 770451 |
| the molybdenum--iron protein of klebsiella pneumoniae nitrogenase. evidence for non-identical subunits from peptide 'mapping'. | the molybdenum- and iron-containing protein components of nitrogenase purified from klebsiella pneumoniae, azotobacter vinelandii, azotobacter chroococcum and rhizobium japonicum bacteroids all gave either one or two protein-staining bands after sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, depending on the commercial brand of sodium dodecyl sulphate used. the single band obtained with k. pneumoniae mo-fe protein when some commercial brands of sodium dodecyl sulphate were used in t ... | 1976 | 779772 |
| symmetry and asymmetry of the pyruvate dehydrogenase complexes from azotobacter vinelandii and escherichia coli as reflected by fluorescence and spin-label studies. | fluorescence-lifetime measurements of fad bound to lipoamide dehydrogenase from azotobacter vinelandii and escherichia coli were performed. it is shown from these results that the two fad groups in the isolated dimeric enzyme, as well as in the enzyme in the intact complex of e. coli, are in non-equivalent surroundings. this contrasts with the near equivalence of the fad groups of both the enzyme and complex isolated from a. vinelandii. reduction of the complex with mg2+, thiamine pyrophosphate ... | 1976 | 795671 |
| kinetics of dithionite ion utilization and atp hydrolysis for reactions catalyzed by the nitrogenase complex from azotobacter vinelandii. | the kinetics of s2o42-utilization and atp hydrolysis during the nitrogenase-catalyzed h2 evolution and acetylene and nitrogen-reducing reactions were studied using a polarographic technique to monitor-s2o42-concentration. rate constants for both s2o42-utilization and atp hydrolysis were determined as a function of temperature and corresponding activation energies determined. the activation energy for atp hydrolysis differs from that for product formation or s2o42-utilization by 5 kcal/mol above ... | 1977 | 836787 |
| generation of a transmembrane electric potential during respiration by azotobacter vinelandii membrand vesicles. | membrane vesicles isolated from azotobacter vinelandii strain o by lysis of spheroplasts in potassium of sodium phosphate buffer develop a transmembrane electric potential during respiration. the magnitude of this potential was determined by three independent methods: (i) fluorescence of 3,3'-dipropylthiodicarbocyanine and 3,3'-dihexyloxacarbocyanine; (ii) uptake of 86rb+ in the presence of valinomycin; and (iii) uptake of [3h]triphenylmethyl phosphonium. in method (i), the relative fluorescence ... | 1977 | 838687 |
| influence of oxygen on phospholipid production and colony formation in a nitrogen-fixing mutant of azotobacter vinelandii. | colony dimorphism in a conditional nitrogen-fixing mutant of azotobacter vinelandii was directly influenced by fixed nitrogen and oxygen partial pressure and may be related to the production of internal peripheral membrane. | 1977 | 863859 |
| technique for isolating phage for azotobacter vinelandii. | an enrichment technique was developed whereby azotophage could readily be isolated after inoculation of soil sites with azotobacter vinelandii. | 1977 | 869522 |
| the molecular weight of, and evidence for two types of subunits in, the molybdenum-iron protein of azotobacter vinelandii nitrogenase. | the weight-average molecular weight of the mo-fe protein isolated from azotobacter vinelandii has been determined by sedimentation-equilibrium techniques. in buffer, the value is 245000+/-5000; in 8m-urea, the value is 61000+/-1000. the protein was separated into two components by chromatography on cm-cellulose in 7m-urea, ph 4.5. these components have similar molecular weights but were shown to differ in charge, amino acid content and arginine-containing peptides. it is proposed that the tetra ... | 1977 | 880213 |
| inhibition of azotobacter vinelandii rna polymerase by cibacron blue f3ga. | cibacron blue f3ga is a potent inhibitor of the azotobacter vinelandii dna-directed rna polymerase. addition of 8 micrometer cibacron blue f3ga prior to initiation results in a greater than 90% inhibition of the poly[d(a-t]-directed synthesis of poly[r(a-u)] while addition of the dye during the course of the reaction is without effect on chain elongation. binding of rna polymerase to [3h]poly[d(a-t)] is inhibited by only 15% in the presence of 8 micrometer cibacron blue f3ga. inhibition by cibac ... | 1977 | 885877 |
| complete amino acid sequence of azotoflavin, a flavodoxin from azotobacter vinelandii. | | 1977 | 889809 |
| a unique envelope protein in azotobacter vinelandii. | | 1977 | 901546 |
| involvement of the cytoplasmic membrane in nitrogen fixation by azotobacter vinelandii. | | 1977 | 908330 |
| transformation of the 4-component pyruvate dehydrogenase complex from azotobacter vinelandii into a 3-component complex. | | 1977 | 913582 |
| intergeneric transfer of genes involved in the rhizobium-legume symbiosis. | genes that seem to be involved in the initial steps of infection of a legume by rhizobium have been transferred, by transformation, to mutant strains of azotobacter vinelandii that are unable to fix nitrogen. these genes code for a surface antigen that binds specifically to a protein from the host plant. | 1977 | 929179 |
| comparison of initial velocity and binding data for allosteric adenosine monophosphate nucleosidase. | adensine monophosphate nucleosidase (amp nucleosidase) from azotobacter vinelandii is composed of six subunits with similar or identical charge and size and has a molecular weight of approximately 320,000. binding studies with tritiated tubercidin 5' -po4 (4-amino-7-(beta-d-ribofuranosyl)pyrrolo[2,3-d]pyrimidine-5' -monophosphate), a competitive inhibitor with respect to the substrate, amp, indicate the presence of three independent, identical binding sites for the substrate analog. the binding ... | 1976 | 931993 |
| iron-sulfur clusters and cysteine distribution in a ferredoxin from azotobacter vinelandii. | | 1976 | 938514 |
| use of immunoadsorbent affinity chromatography to purify component i of nitrogenase from extracts of azotobacter vinelandii. | | 1976 | 955078 |