| factors affecting growth and nitrogen fixation of spirillum lipoferum. | spirillum lipoferum grows vigorously on malate, succinate, lactate, or pyruvate, moderately on galactose or acetate, and poorly on glucose or citrate. it reduces 15n2. acetylene reduction rates decrease rapidly when the ph of the culture rises above 7.8. the organism is highly aerobic and had doubling times as low as 2 h when grown on nh4+. however, s. lipoferum reduces n2 well only under microaerophilic conditions. the optimal po2 for acetylene reduction by stagnant cultures was 0.006 to 0.02 a ... | 1976 | 8430 |
| ecological distribution of spirillum lipoferum beijerinck. | a survey in various countries revealed that the n2-fixing spirillum lipoferum beijerinck is a very common root and soil inhabitant in the tropics. more than half of the grass root and soil samples collected in tropical countries (four african countries and brazil) contained abundant s. lipoferum populations, while less than 10% of the samples collected in temperate south brazil, kenya, and the u.s.a. contained the organism. there is a pronounced vegetation effect. panicum maximum seems the most ... | 1976 | 10062 |
| carbon and ammonia metabolism of spirillum lipoferum. | intact cells and extracts from spirillum lipoferum rapidly oxidized malate, succinate, lactate, and pyruvate. glucose, galactose, fructose, acetate, and citrate did not increase the rate of o2 uptake by cells above the endogenous rate. cells grown on nh+/4 oxidized the various substrates at about the same rate as did cells grown on n2. added oxidized nicotinamide adenine dinucleotide generally enhanced o2 uptake by extracts supplied organic acids, whereas oxidized nicotinamide adenine dinucleoti ... | 1976 | 10278 |
| growth of spirillum lipoferum at constant partial pressures of oxygen, and the properties of its nitrogenase in cell-free extracts. | spirillum lipoferum, an n2-fixing organism, was grown at constant concentrations of dissolved o2. when supplied with nh4+ aerobically, its doubling time was 1 h; when it fixed n2 microaerophilically, its doubling time was 5-5 to 7 h and the optimal po2 for growth was 0-005 to 0-007 atm. at its optimal po2 for growth on n2, s. lipoferum assimilated 8 to 10 mg nitrogen/g carbon substrate used; its efficiency was less at higher po2 levels. nitrogenase in cell-free extracts required mg2+ and mn2+, a ... | 1977 | 13147 |
| nitrogen fixation, denitrification, and pleomorphic growth in a highly pigmented spirillum lipoferum. | 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 c ... | 1977 | 22311 |
| 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. | | 1979 | 295269 |
| physiological studies of spirillum lipoferum. | | 1977 | 411476 |
| deoxyribonucleic acid-mediated transformation of spirillum lipoferum. | the methodology for deoxyribonucleic acid-mediated transformation of spirillum lipoferum to resistance to various antimicrobial agents is reported. | 1979 | 438124 |
| inducing effect of plant cells on nitrogenase activity by spirillum and rhizobium in vitro. | eleven different plant cell tissue cultures of both legume and non-legume origin have been grown in direct association, and in separate but close proximal association with both spirillum lipoferum and rhizobium sp. 32h1. basic similarities were found in the nutritional requirement for the induction of nitrogenase activity (c2h2) in both organisms. in the absence of plant cell cultures both organisms need to be provided with a pentose sugar and a tricarboxylic acid to induce high levels of nitrog ... | 1978 | 647472 |
| light microscopy observations of tetrazolium-reducing bacteria in the endorhizosphere of maize and other grasses in brazil. | roots of field-grown tropical maize, panicum maximum jacq. and digitaria decumbens stent., and of sorghum and wheat grown in monoxenic culture with the diazotroph spirillum lipoferum (syn. azospirillum spp.) were examined for tetrazolium-reducing bacteria following incubation of roots in a malate-phosphate buffer-2,3,5-triphenyltetrazolium chloride medium. bacteria were observed between and in cells of the cortex, in intercellular spaces between the cortex and endodermis, in xylem cells, and in ... | 1978 | 667740 |
| nitrate and nitrite reductase negative mutants of n2-fixing azospirillum spp. | chlorate resistant spontaneous mutants of azospirillum spp. (syn. spirillum lipoferum) were selected in oxygen limited, deep agar tubes with chlorate. among 20 mutants from a. brasilense and 13 from a. lipoferum all retained their functional nitrogenase and 11 from each species were nitrate reductase negative (nr-). most of the mutants were also nitrite reductase negative (nir-), only 3 remaining nir+. two mutants from nr+ nir+ parent strains lost only nir and became like the nr+ nir- parent str ... | 1978 | 697499 |
| the nitrogenase system of spirillum lipoferum. | the nitrogenase system of spirillum lipoferum was separated into three components, the normal mo-fe and fe proteins as well as an activating factor for the fe protein. the rate of activation is increased by mn2+ or by an excess of mg2+, and the process requires atp. | 1978 | 708367 |
| effect of oxygen and nitrate on nitrogen fixation and denitrification by azospirillum brasilense grown in continuous culture. | 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 mecha ... | 1978 | 743647 |
| denitrification by n2-fixing sprillum lipoferum. | 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 ... | 1977 | 851911 |
| nitrate reduction nitrogenase activity in spirillum lipoferum1. | nitrate and nitrite reduction under aerobic, microaerophillic, and anaerobic conditions was demonstrated in spirillum lipoferum (atcc 29145). nitrite did not accumulated during assimilatory nitrate reduction in air. the nitrite produced during dissimilatory nitrate reduction accumulated in the medium but not in the cells. on exposure of the bacteria to nitrate and anaerobiosis, a low initial rate (lag) was followed by accelerated rates of nitrite accumulation. a 3-h anaerobic pretreatment, in th ... | 1977 | 856423 |
| taxonomic studies of spirillum lipoferum. | | 1977 | 921697 |
| [azospirillum brasilense sp245 mutants in production of anthranilic and indolyl-3-acetic acids]. | the mutants of azospirillum brasilense sp245 altered in the production of anthranilic (ant) and indolyl-3-acetic (iaa) acids were selected after the chemical or transposon facilitated mutagenesis and divided into the following three classes: ant+iaa+, ant+iaa- and ant-iaa-. a hypothesis on the existence of a pattern for tryptophan conversion to anthranilate that is different from the classic pattern, and on the connection of the indolyl-3-acetic synthesis with this process is suggested. | 1992 | 1298884 |
| [plasmid p85 from azospirillum brasilense sp245: study of the circle of possible hosts and incompatibility with plasmids from azospirillum brasilense sp7]. | the possibility of the stable inheritance of the plasmid p85 mobilized derivatives from azospirillum brasilense sp245 in the cells of the bacterial genera rizobiaceae (agrobacterium tumfaciens) and pseudomonadaceae (pseudomonas putida) has been shown. the plasmid p85 participates in coding for the physiologically active products (the plant hormones). it is not inherited by the escherichia coli strains. for the first time the incompatibility of azospirillium plasmids has been demonstrated on the ... | 1992 | 1298886 |
| nitrogenase activity in wheat seedlings bearing para-nodules induced by 2,4-dichlorophenoxyacetic acid (2,4-d) and inoculated with azospirillum. | nitrogenase activity (c2h2 reduction) was demonstrated in seedlings of wheat roots bearing para-nodules induced by 2,4-dichlorophenoxyacetic acid (2,4-d) and inoculated with azospirillum brasilense. increased nitrogenase activity was observed in inoculated para-nodulated seedlings as compared to inoculated roots not treated by 2,4-d under the conditions of assay used. 2,4-d had no stimulating effect on plant ethylene production in the absence of acetylene. when inoculation was performed with a n ... | 1992 | 1299838 |
| characterization of the flavins and the iron-sulfur centers of glutamate synthase from azospirillum brasilense by absorption, circular dichroism, and electron paramagnetic resonance spectroscopies. | azospirillum brasilense glutamate synthase has been studied by absorption, electron paramagnetic resonance, and circular dichroism spectroscopies in order to determine the type and number of iron-sulfur centers present in the enzyme alpha beta protomer and to gain information on the role of the flavin and iron-sulfur centers in the catalytic mechanism. the fmn and fad prosthetic groups are demonstrated to be non-equivalent with respect to their reactivities with sulfite. sulfite reacts with only ... | 1992 | 1316154 |
| regulation of nitrogen fixation in azospirillum brasilense sp7: involvement of nifa, glna and glnb gene products. | the expression of nifa-, nih- and nifb-lacz fusions was examined in different mutants of azospirillum brasilense. mutations in nifa, glna and glnb severely impaired the expression of nifh- and nifb-lacz fusions. by contrast, a nifa-lacz fusion was not affected in a nifa or a glnb background and was only partially impaired in glna mutants. it is proposed that in a. brasilense, the pii protein and glutamine synthetase are involved in a post-translational modification of nifa. | 1992 | 1362170 |
| in vitro protein synthesis is affected by the herbicide 2,4-dichlorophenoxyacetic acid in azospirillum brasilense. | the effects of 2,4-dichlorophenoxyacetic acid (2,4-d) on growth and protein, dna and rna synthesis of azospirillum brasilense cd were studied. at a concentration of 1 mm, 2,4-d inhibited cell growth, an effect that was reversed either by transferring bacteria to a control (2,4-d-free) medium or to a 2,4-d-treated medium supplemented with polyamines. the herbicide also affected in vitro protein synthesis, either when azospirillum brasilense cd's own cellular mrna or an artificial mrna was used. t ... | 1992 | 1375402 |
| [conjugative transfer of plasmid dna between bacteria in soil]. | conjugative transfer of plasmid rp4 between populations of azospirilla and between escherichia coli and azospirillum brasilense in nonsterile soil has been investigated. the process of genetic exchange was realized at the early stages of interpopulational interactions, further on the process intensity was obviously rather low. population dynamics of azospirilla transconjugates in soil depends on the presence or the absence of additional food substrate. | 1992 | 1474945 |
| characterization of an azospirillum brasilense sp7 gene homologous to alcaligenes eutrophus phbb and to rhizobium meliloti nodg. | a 4 kb sali fragment from azospirillum brasilense sp7 that shares homology with a 6.8 kb ecori fragment carrying nodgefh and part of nodp of rhizobium meliloti 41 was cloned in puc18 to yield pab503. the nucleotide sequence of a 2 kb sali-smai fragment of the pab503 insert revealed an open reading frame, named orf3, encoding a polypeptide sharing 40% identity with r. meliloti nodg. the deduced polypeptide also shared 60% identity with the alcaligenes eutrophus nadph-dependent acetoacetyl-coa (aa ... | 1992 | 1538694 |
| transcription of the azospirillum brasilense nifh gene is positively regulated by nifa and ntra and is negatively controlled by the cellular nitrogen status. | the expression of a translational azospirillum brasilense nifh-uida fusion was studied in a. brasilense and in rhizobium meliloti strains with mutations in nifa, ntra and ntrc. induction of the fusion was observed in the r. meliloti wild-type and ntrc- strains on incubation under microaerobic conditions but not in the nifa- and ntra- strains, showing the absolute requirement of both sigma 54 and nifa for activation of the nifh promoter. histochemical analysis of the root nodules elicited by r. m ... | 1992 | 1557035 |
| cloning, sequencing, mutagenesis, and functional characterization of drat and drag genes from azospirillum brasilense. | the azospirillum brasilense drat gene, encoding dinitrogenase reductase atp-ribosyltransferase, and drag gene, encoding dinitrogenase reductase activating glycohydrolase, were cloned and sequenced. two genes were contiguous on the a. brasilense chromosome and showed extensive similarity to the same genes from rhodospirillum rubrum. analysis of mutations introduced into the dra region on the a. brasilense chromosome showed that mutants affected in drat were incapable of regulating nitrogenase act ... | 1992 | 1577701 |
| mechanistic studies on azospirillum brasilense glutamate synthase. | the reaction mechanism of azospirillum brasilense glutamate synthase has been investigated by several approaches. 15n nuclear magnetic resonance studies demonstrate that the amide nitrogen of glutamine is reductively transferred to 2-oxoglutarate in an irreversible manner with no release of the transferred ammonia group into the medium. identical results were obtained using thio-nadph and acetylpyridine-nadph, which are shown to be less efficient substrates of the enzyme than nadph. similarly, n ... | 1991 | 1683791 |
| characterization of three different nitrogen-regulated promoter regions for the expression of glnb and glna in azospirillum brasilense. | the complete nucleotide sequence of the open reading frame (orf) located upstream of the glna structural gene for glutamine synthetase (gs) in azospirillum brasilense sp7 was determined. this orf, which codes for a 12 kda protein, was identified as glnb, the structural gene for the pii protein, a component of the adenylylation cascade involved in the regulation of gs activity in some gram-negative bacteria. transcription analysis and mrna mapping of glnb and glna of a. brasilense was performed w ... | 1990 | 1702507 |
| characterization of an osmoregulated periplasmic glycine betaine-binding protein in azospirillum brasilense sp7. | azospirillum brasilense is able to use glycine betaine as a powerful osmoprotectant; the uptake of this compound is strongly stimulated by salt stress, but significantly reduced by cold osmotic shock. non-denaturing page in the presence of [methyl-14c] glycine betaine and autoradiography demonstrated the presence of one glycine betaine-binding protein (gbbp) in periplasmic shock fluid obtained from high-osmolarity-grown cells. the binding activity was absent in periplasmic fractions from cells g ... | 1991 | 1747385 |
| identification and mapping of loci involved in motility, adsorption to wheat roots, colony morphology, and growth in minimal medium on the azospirillum brasilense sp7 90-mda plasmid. | we have constructed a cosmid library of the azospirillum brasilense sp7 90-mda plasmid (p90) and established the ecori restriction map of this plasmid. the central regions of cloned p90 dna fragments from several recombinant cosmids were deleted by restriction endonuclease digestion and replaced by a dna cassette encoding kanamycin resistance. using these in vitro constructed deletions for marker exchange in sp7, we made six different p90 deletion derivatives spanning all together 50% of the tot ... | 1991 | 1749822 |
| [transfer of transformation and conjugation plasmids from escherichia coli to bacillus subtilis and azospirillum brasilense]. | the conjugative transfer of rp4 plasmid from escherichia coli to azospirillum brasilense was detected after introduction and subsequent incubation of these microorganisms in soil. the plasmid transfer via transformation from escherichia coli to bacillus subtilis was observed in case both bacteria were growing together in sand containing sucrose solution. the possible reason for low frequency interspecies plasmid transformation under conditions close to natural habitats is poor survival of "domes ... | 1991 | 1758472 |
| the production and utilization of nitric oxide by a new, denitrifying strain of pseudomonas aeruginosa. | when a new strain of pseudomonas aeruginosa was grown aerobically and then transferred to anaerobic conditions, cells reduced no3- quantitatively to no2- in no3(-)-respiration. in the absence of nitrate, no2- was immediately reduced to no or n2o but not to n2 indicating that no2(-)-reductase but not n2o-reductase was active. the formation of the products no or n2o depended on the ph in the medium and the concentration of no2- present. when p. aeruginosa was grown anaerobically for at least three ... | 1991 | 1772347 |
| 1,8-naphthalic anhydride antidote enhances the toxic effects of captan and thiram fungicides on azospirillum brasilense cells. | the effects of ten fungicides, six herbicides and four insecticides on the nitrogen-fixing bacterium azospirillum brasilense were examined. the fungicides captan and thiram were the most toxic among the compounds tested. cell growth and nitrogenase activity of the bacterium were markedly inhibited by low concentrations of the two fungicides. antidote 1,8-naphthalic anhydride increased by a factor of 2 the cellular level of glutathione. the addition of the antidote in the presence of captan or th ... | 1991 | 1805302 |
| the nifhdk operon in the free-living nitrogen-fixing bacteria azospirillum brasilense sequentially comprises genes h, d, k, an 353 bp orf and gene y. | 1. the complete nucleotide sequence of the nitrogenase structural genes from azospirillum brasilense was determined. two additional open reading frames of 353 and 683 base pairs were detected downstream of the nifk gene, one of which shows homology to the nify gene. 2. structures resembling the consensus nif promoter and nifa-binding motif were found only upstream from the nifh region and an inverted repeat structure located downstream of the nify gene may be a potential stem-and-loop transcript ... | 1991 | 1823284 |
| cloning and characterization of the nifa gene from herbaspirillum seropedicae strain z78. | a genomic library of herbaspirillum seropedicae was constructed and screened for the nifa gene by complementation of a nifa mutant of azospirillum brasilense (fp10). a recombinant plasmid, pems1, capable of restoring acetylene reduction activity in the mutant fp10, was isolated and found to hybridize to the nifa gene of klebsiella pneumoniae. the results suggest that nifa is involved in the regulation of nif genes in h. seropedicae. | 1991 | 1913346 |
| the kinetic mechanism of the reactions catalyzed by the glutamate synthase from azospirillum brasilense. | the reactions catalyzed by glutamate synthase from azospirillum brasilense have been investigated by a combination of absorption spectroscopy, steady-state kinetic measurements and experiments with stereospecifically labelled substrate. the data show that both l-glutamine-dependent and ammonia-dependent reactions of the glutamate synthase from a. brasilense follow an identical two-site uni-uni bi-bi kinetic mechanism, in which the enzyme is alternately reduced by nadph and oxidized by the iminog ... | 1991 | 1935975 |
| detection of alternative nitrogenases in aerobic gram-negative nitrogen-fixing bacteria. | strains of aerobic, microaerobic, nonsymbiotic, and symbiotic dinitrogen-fixing bacteria were screened for the presence of alternative nitrogenase (n2ase) genes by dna hybridization between genomic dna and dna encoding structural genes for components 1 of three different enzymes. a nifdk gene probe was used as a control to test for the presence of the commonly occurring mo-fe n2ase, a vnfdgk gene probe was used to show the presence of v-fe n2ase, and an anfdgk probe was used to detect fe n2ase. ... | 1991 | 1987127 |
| characterization of two azospirillum brasilense sp7 plasmid genes homologous to rhizobium meliloti nodpq. | bacteria belonging to the azospirillum genus are nitrogen fixers that colonize the roots of grasses, but do not cause the formation of differentiated structures. sequences from total dna of several azospirillum strains are homologous to restriction fragments containing rhizobium meliloti nodulation genes. a 10-kilobase (kb) ecori fragment from a. brasilense sp7, sharing homology with a 6.8-kb ecori fragment carrying nodgefh and part of nodp of r. meliloti 41, was cloned in puc18 to yield pab502. ... | 1990 | 2131098 |
| production of bacteriocins and siderophore-like activity by azospirillum brasilense. | sixty azospirillum strains were tested for their bacteriocin production ability; twenty-seven (45%) were able to produce bacteriocins and inhibited the growth of one or more indicator strains in solid medium. mitomycin c treatment enhanced the proportion to 80%. sometimes large growth inhibition zones were formed, but not when fecl3 was added in the medium. these inhibition zones probably result from the activity of siderophores. partially purified bacteriocins produced by four strains were inac ... | 1990 | 2148964 |
| [transposon mutagenesis, elimination and mobilization of plasmids in nitrogen-fixating bacterium azospirillum brasilense sp245]. | the expressed difference in the plasmid profile of a. brasilense sp245 is registered as a result of tn5-mob-mutability. integration of the vector psup5011 into one of the a. brasilense sp245 plasmid and using of the tn5-mob transposon to mobilize the 85md cryptic plasmid are reported. the properties of a. brasilense sp245 with the mutant plasmids composition (surface structure, acetylene and nitrate reduction, ability to a number of carbohydrates utilization, formation of melanin, antibiotics re ... | 1990 | 2159109 |
| isolation of behavioral mutants of azospirillum brasilense by using tn5 lacz. | tn5 lacz mutants were generated with azospirillum brasilense 7030 by mating that strain with escherichia coli strains carrying suicide plasmid pcib100 or pcib110. kanamycin-resistant azospirillum colonies were obtained with a maximum frequency of 10(-6) per recipient cell. the potential of tn5 lacz for random transposon mutagenesis coupled to transcription analysis in a. brasilense 7030 was demonstrated. sixty percent of all kmr a. brasilense 7030 mutants expressed beta-galactosidase activity. m ... | 1990 | 2160221 |
| construction of an azospirillum brasilense sp7 reca mutant. | cosmid clones encoding the reca gene of azospirillum brasilense were isolated by intergeneric complementation of an escherichia coli reca mutant. site-directed tn5 mutagenesis and subcloning of one complementing cosmid clone allowed us to localize the a. brasilense reca gene on a 1.2 kb dna fragment. one tn5 insertion that inactivates the cloned reca gene was crossed into the chromosome of a. brasilense by marker exchange. the resulting a. brasilense reca mutant showed increased sensitivity to t ... | 1990 | 2175386 |
| structural studies on the subunits of glutamate synthase from azospirillum brasilense. | the amino acid composition and the n-terminal sequences of the two dissimilar subunits of glutamate synthase from azospirillum brasilense have been determined along with the sequences of selected cnbr peptides. comparison of our data with those available for escherichia coli glutamate synthase revealed an overall good homology between the enzymes from the two sources. this is more evident for the heavy subunits where the highly conserved n-terminal sequence containing cys-1, suggests that this r ... | 1990 | 2198943 |
| physical map and properties of a 90-mda plasmid of azospirillum brasilense sp7. | homology was previously detected between the dna restriction fragments containing rhizobium meliloti nodulation genes and the 90-mda plasmid, p90, of azospirillum brasilense sp7. two dna loci from sp7 genome that complement mutations in the exopolysaccharide synthesis genes, exob and exoc, of r. meliloti were also shown to be present on the plasmid. a more detailed characterization of the plasmid was undertaken to establish its physical map and to localize the nod homologies and other specific r ... | 1990 | 2217570 |
| nucleotide sequence of the nodg gene of azospirillum brasilense. | | 1990 | 2243795 |
| involvement of azospirillum brasilense plasmid dna in the production of indole acetic acid. | indole acetic acid (iaa) production in azospirillum brasilense strain sp245 is controlled by a 85 mda plasmid naturally present in this bacterium. in the presence of l-tryptophan, anthranilic acid production and almost no iaa production occurs in a derivative strain harbouring a tn5-mob insertion in the 85 mda plasmid. agrobacterium tumefaciens strain gm19023, upon transfer of tn5-mob labelled 85 mda plasmid of a. brasilense sp245, gains the ability to produce anthranilic acid. | 1990 | 2283026 |
| expression of the agrobacterium tumefaciens chvb virulence region in azospirillum spp. | inner membranes of azospirillum brasilense incubated with udp-glucose were unable to synthesize beta-(1-2) glucan and lacked the 235-kilodalton intermediate protein known to be involved in the synthesis of beta-(1-2) glucan in agrobacterium tumefaciens and rhizobium meliloti. inner membranes of a. brasilense strains carrying a cosmid containing the chromosomal virulence genes chva and chvb of agrobacterium tumefaciens formed beta-(1-2) glucan in vitro and synthesized the 235-kilodalton intermedi ... | 1990 | 2332404 |
| ferrochelatase activity in azospirillum brasilense with reference to the influence of metal cations. | ferrochelatase in membrane preparations from azospirillum brasilense displayed an activity of 2.17 mumol protoheme formed.h-1.mg protein-1 which is 10-fold greater than previous reports for other bacteria. this ferrochelatase showed an apparent km of 20.9 microm for fe2+, a ph optimum of 6.0-6.5, and stimulation by oleic or stearic acids. co2+, cu2+ and zn2+ inhibited the incorporation of fe2+ into protoporphyrin ix while ni2+ and mg2+ had no effect on protoheme synthesis. activity with fe2+ and ... | 1989 | 2485650 |
| posttranslational regulatory system for nitrogenase activity in azospirillum spp. | the mechanism for "nh4+ switch-off/on" of nitrogenase activity in azospirillum brasilense and a. lipoferum was investigated. a correlation was established between the in vivo regulation of nitrogenase activity by nh4cl or glutamine and the reversible covalent modification of dinitrogenase reductase. dinitrogenase reductase adp-ribosyltransferase (drat) activity was detected in extracts of a. brasilense with nad as the donor molecule. dinitrogenase reductase-activating glycohydrolase (drag) activ ... | 1989 | 2504694 |
| temperature inhibition of siderophore production in azospirillum brasilense. | the effect of growth at 42 degrees c on the different components of the siderophore-mediated iron transport that are induced by iron limitation in azospirillum brasilense was examined. biosynthesis of the siderophore spirilobactin was strongly inhibited (20-fold) by growth at 42 degrees c, whereas the transport of iron by the ferric-spirilobactin transport system and the induction of the iron-regulated outer membrane proteins were unaffected. | 1989 | 2525551 |
| plasmid localization and mapping of two azospirillum brasilense loci that affect exopolysaccharide synthesis. | two azospirillum brasilense loci that correct rhizobium meliloti exob and exoc mutants for exopolysaccharide (eps) synthesis have been identified previously (k. w. michiels, j. vanderleyden, a. p. van gool, e. r. signer, j. bacteriol., 1988b). a. brasilense exo mutants produce eps of lower molecular weight than the wild type strain. here, we show by hybridization that these exo loci are located on a 90-mda plasmid in a. brasilense sp7. in four other azospirillum strains but not in a. lipoferum s ... | 1989 | 2544914 |
| [the role of chemotaxis genes in establishing the associative relations between azospirillum brasilense and wheat]. | the chemotactic properties of a number of azospirillum brasilense natural strains have been studied. azospirillum demonstrate the positive chemotactic reaction towards the organic acids salts but a poor reaction towards the presence of the attractants like hydrocarbons and aminoacids except for arabinose and glutamic acid. the series of che- mutants deficient in general chemotaxis has been selected by introducing the transposon tn5 into the cells of rifampicinresistant mutant strain azospirillum ... | 1989 | 2546068 |
| identification of a regulatory nifa type gene and physical mapping of cloned new nif regions of azospirillum brasilense. | three new tn5-mutagenized nif genes of azospirillum brasilense were characterized. the sizes of the restriction fragments and the restriction maps of the cloned nif dna regions showed that these nif genes are distinct from those reported earlier, e.g. nifhdk, nife, nifus, fixabc. the nif27 mutant was identified as a nifa type regulatory gene of a. brasilense (a) by genetic complementation with nifa of klebsiella pneumoniae, (b) by the absence of nitrogenase iron protein in western protein blots ... | 1989 | 2559312 |
| nucleotide sequence of the gene encoding the nitrogenase iron protein (nifh) of azospirillum brasilense and identification of a region controlling nifh transcription. | the dna sequence was determined for the azospirillum brasilense nifh gene and part of the nifd gene. the nifh gene is 885 bp long and encodes 293 amino acid residues. the region upstream of the nifh open reading frame contains a putative promoter whose sequence shows perfect homology with promoters of other diazotrophic bacteria and two putative upstream activator sequences. experiments with the promoter-probe vector paf300 showed that this region promotes transcription in response to the nitrog ... | 1989 | 2608029 |
| regulation of transcription and promoter mapping of the structural genes for nitrogenase (nifhdk) of azospirillum brasilense sp7. | transcription of the structural genes for nitrogenase (nifhdk) in azospirillum brasilense sp7 was analysed using northern blots of total rna extracted from cultures grown under nitrogen-fixing conditions. hybridization with an internal nifh probe revealed two transcripts, a major one (by concentration) of 1.1 kb corresponding to nifh and a minor one of 5.6 kb corresponding to nifhdk. hybridization with nifd or nifk probes revealed the minor transcript of 5.6 kb. this confirms that the nifhdk gen ... | 1989 | 2608030 |
| cloning of histidine genes of azospirillum brasilense: organization of the abfh gene cluster and nucleotide sequence of the hisb gene. | a cluster of four azospirillum brasilense histidine biosynthetic genes, hisa, hisb, hisf and hish, was identified on a 4.5 kb dna fragment and its organization studied by complementation analysis of escherichia coli mutations and nucleotide sequence. the nucleotide sequence of a 1.3 kb fragment that complemented the e. coli hisb mutation was determined and an orf of 624 nucleotides which can code for a protein of 207 amino acids was identified. a significant base sequence homology with the carbo ... | 1989 | 2664449 |
| cloning and expression in escherichia coli of the azospirillum brasilense sp7 gene encoding ampicillin resistance. | the azospirillum brasilense atcc 29145 gene coding for beta-lactamase was cloned in escherichia coli. the gene was expressed in e. coli from its own promoter as a 30-kilodalton protein, conferring resistance to high levels of beta-lactam antibiotics. the dna sequence containing the beta-lactamase gene was found to be highly amplified in the azospirillum genome, scattered in the chromosomal as well as in the plasmidic dna. | 1989 | 2675764 |
| identification of dna regions homologous to nitrogen fixation genes nife, nifus and fixabc in azospirillum brasilense sp7. | a 30 kb dna region from azospirillum brasilense sp7, containing the nitrogenase structural genes (nifhdk), has been cloned. the presence of nif genes, in the 20 kb located next to nifhdk, was explored by tn5 mutagenesis after subcloning various restriction fragments in the broad-host-range suicide vehicle psup202. over 25 mutations due to tn5 random insertions were obtained in the 20 kb and each recombined into the genome of strain sp7. four new nif loci were identified, located at about 4, 9, 1 ... | 1989 | 2695597 |
| lack of expression of rp4-specified beta-lactamase in azospirillum brasilense. | plasmid rp4, which normally confers resistance to ampicillin (apr), tetracycline (tcr), and kanamycin (kmr) to its hosts, failed to express enhanced apr when transferred from escherichia coli to azospirillum brasilense which has its own intrinsic beta-lactamase. even in a beta-lactamase-deficient mutant, a. brasilense rg-d16, no increase in beta-lactamase or significant apr appeared following transfer of rp4. however, a. brasilense rg (rp4) and a. brasilense rg-d16 (rp4) did exhibit tcr kmr. whe ... | 1989 | 2699042 |
| calcofluor- and lectin-binding exocellular polysaccharides of azospirillum brasilense and azospirillum lipoferum. | extracellular polysaccharides synthesized by azospirillum brasilense and a. lipoferum were shown on agar plates and liquid flocculating cultures. the six strains used in this work expressed a mucoid phenotype, yielding positive calcofluor fluorescence under uv light. the calcofluor-binding polysaccharides were distributed between the capsular and exopolysaccharide fractions, suggesting exocellular localization. no calcofluor fluorescence was observed in residual cells after separation of the cap ... | 1989 | 2722757 |
| [formation of pas8-1213 cointegrate with one of the plasmids of azospirillum brasilense sp245]. | inheritance of the plasmid vector pas8-1213 in azospirillum brasilense sp245 cells has been studied. the plasmid pas8-1213 is shown to be uncapable of autonomous replication in the new host but able to integrate into the genetic structures of azospirillum with high frequency. 90-95% of kmr-transconjugants of a. brasilense harbor pas8-1213 cointegrated with the smaller host plasmid pabsp245c(85md). the formed cointegrate can be transferred into azospirillum spp. 75 and reca- strains of e. coli (h ... | 1989 | 2811907 |
| construction of a gene library from azospirillum brasilense and characterization of a recombinant containing the nif structural genes. | 1. we have constructed a gene library, from azospirillum brasilense using the vector embl4. 2. a recombinant containing the nif structural genes from a. brasilense was isolated and characterized. this recombinant contains a dna insert of about 15 kilobases (kb) which gives rise to five fragments after cleavage with ecori. only one of the dna fragments (6.5 kb) hybridized to the nifhdk genes of klebsiella pneumoniae. 3. the organization of the nif genes in this dna fragment was determined using d ... | 1987 | 2837298 |
| nucleotide sequence of the azospirillum brasilense sp7 glutamine synthetase structural gene. | the complete nucleotide sequence of the glna gene, encoding the glutamine synthetase subunit of azospirillum brasilense sp7, was established. this is the first azospirillum gene sequenced. the gene encodes a 468 residue polypeptide of mw 51,917. the similarity coefficient (sab) between the polypeptidic sequence of azospirillum and anabaena 7120, which is the only other glna sequence available, is 58%. no significant homology with e. coli canonical and ntr promoters, or with the promoter region o ... | 1986 | 2878685 |
| regulation of nitrogenase activity by oxygen in azospirillum brasilense and azospirillum lipoferum. | the nitrogenase activity of the microaerophilic bacteria azospirillum brasilense and a. lipoferum was completely inhibited by 2.0 kpa of oxygen (approximately 0.02 atm of o2) in equilibrium with the solution. the activity could be partially recovered at optimal oxygen concentrations of 0.2 kpa. in contrast to the nh4+ switch off, no covalent modification of the nitrogenase reductase (fe protein) was involved, as demonstrated by western-blotting and 32p-labeling experiments. however, the inhibiti ... | 1987 | 2880836 |
| assimilation of 13nh4+ by azospirillum brasilense grown under nitrogen limitation and excess. | the specific activities of glutamine synthetase (gs) and glutamate synthase (gogat) were 4.2- and 2.2-fold higher, respectively, in cells of azospirillum brasilense grown with n2 than with 43 mm nh4+ as the source of nitrogen. conversely, the specific activity of glutamate dehydrogenase (gdh) was 2.7-fold higher in 43 mm nh4+-grown cells than in n2-grown cells. these results indicate that nh4+ could be assimilated and that glutamate could be formed by either the gs-gogat or gdh pathway or both, ... | 1987 | 2887545 |
| cloning and characterization of the glna gene of azospirillum brasilense sp7. | a plasmid which, by complementation, restored a gln+nif+ phenotype to the gln-nif- azospirillum brasilense mutant 7029, was isolated from a gene bank of total dna of a. brasilense sp7 (atcc 29145) constructed in the broad host range vector pvk100. this plasmid contained the structural gene (glna) for glutamine synthetase. the glna gene was mapped by tn5 insertion and dna hybridization with a klebsiella pneumoniae glna probe. the direction of transcription of glna was determined. the glna product ... | 1986 | 2893582 |
| identification of the klebsiella pneumoniae glnb gene: nucleotide sequence of wild-type and mutant alleles. | the glnb gene of klebsiella pneumoniae, which encodes the nitrogen regulation protein pii, has been cloned and sequenced. the gene encodes a 12429 dalton polypeptide and is highly homologous to the escherichia coli glnb gene. the sequences of a glnb mutation which causes glutamine auxotrophy and of a tn5 induced gln+ suppressor of this mutation were also determined. the glutamine auxotrophy was deduced to be the result of a modification of the uridylylation site of pii, and the suppression was s ... | 1988 | 2907369 |
| regulation of fructose uptake and catabolism by succinate in azospirillum brasilense. | fructose uptake and catabolism in azospirillum brasilense is dependent on three fructose-inducible enzymes (fru-enzymes): (i) enzyme i and (ii) enzyme ii of the phosphoenolpyruvate:fructose phosphotransferase system and (iii) 1-phosphofructokinase. in minimal medium containing 3.7 mm succinate and 22 mm fructose as sources of carbon, growth of a. brasilense was diauxic, succinate being utilized in the first phase of growth and fructose in the second phase with a lag period between the two growth ... | 1987 | 2957360 |
| restriction endonucleases in azospirillum. | azospirillum brasilense, a. amazonense, and a. lipoferum strains were screened for restriction endonucleases using phage lambda dna. the extract of a. brasilense 29711 cleaved lambda dna into specific fragments. it was concluded that this strain possesses a class ii restriction endonuclease which was named abri. abri has a single recognition site on lambda dna at position of approx. 33 500 bp. abri was characterized as an isoschizomer of xhoi, which cuts lambda dna at 33 498 bp and cleaves doubl ... | 1985 | 3000892 |
| regulation of nitrogenase activity by ammonium chloride in azospirillum spp. | ammonium chloride (greater than or equal to 0.05 mm) effectively and reversibly inhibited the nitrogenase activity of azospirillum brasilense, azospirillum lipoferum and azospirillum amazonense. the glutamine synthetase inhibitor l-methionine-dl- sulfoximine abolished this "switch-off" in a. lipoferum and a. brasilense, but not in a. amazonense. azaserine, an inhibitor of glutamate synthase, inhibited nitrogenase activity itself. this provides further evidence for glutamine as a metabolite of re ... | 1986 | 3081492 |
| regulatory mutation that controls nif expression and histidine transport in azospirillum brasilense. | mutagenesis of azospirillum brasilense with nitrosoguanidine and selection on ethylenediamine yielded prototrophs which fixed nitrogen in the presence of ammonia. nitrogenase activity in mutant strains exceeded that of the wild type three- to sixfold. the same mutants were also constitutive for histidine transport. enzyme activities involved in ammonia assimilation were not affected by the mutation. the data suggest that the mutation occurred at a site which regulates nif and histidine transport ... | 1986 | 3087965 |
| cyst production and brown pigment formation in aging cultures of azospirillum brasilense atcc 29145. | encystation in azospirillum brasilense atcc 29145 was observed by using routine laboratory staining and phase-contrast and electron microscopy. encystment occurred in liquid and in solid or semisolid media containing fructose (8 mm) and kno3 (0.5 mm). the encysted forms consisted of a central body filled with poly-beta-hydroxybutyric acid granules, an electron-transparent intinelike region, and a thick outer layer. enlarged giant encysted forms with multiple central bodies were also observed dur ... | 1987 | 3104311 |
| [effect of pesticides on bacterial membranes]. | the effect of pure preparation of ordram, fosalon, ddt, methoxychlorine, hydrel, dihydrel, 2,4-d, 2m-4c and of technical preparations of saturn, linuron, ronstar and keltan on the membrane functions (respiration and motility) of azospirillum brasilense and chromatium minutissimum cells and on malate and nadh oxidation by the isolated membranes of micrococcus lysodeikticus was investigated. the effect varied from irreversible impairment to undetectable impairment of the measured activities depend ... | 1987 | 3112764 |
| isolation and characterization of azospirillum brasilense loci that correct rhizobium meliloti exob and exoc mutations. | the occurrence in azospirillum brasilense of genes that code for exopolysaccharide (eps) synthesis was investigated through complementation studies of rhizobium meliloti exo- mutants. these mutants are deficient in the synthesis of the major acidic eps of rhizobium species and form empty, non-nitrogen-fixing root nodules on alfalfa (j. a. leigh, e. r. signer, and g. c. walker, proc. natl. acad. sci. usa 82:6231-6235, 1985). we demonstrated that the exoc mutation of r. meliloti could be corrected ... | 1988 | 3182731 |
| [response of maize to inoculation with azospirillum brasilense]. | | 1988 | 3244926 |
| a highly sensitive bacterial assay for toxins based on swarming inhibition, and comparison with the cup plate assay based on growth inhibition. | the motility inhibition of the swarming bacteria proteus mirabilis and azospirillum brasilense was found to be an appropriate parameter to indicate toxic effects caused by some mycotoxins, lactones and anhydrides of dicarboxylic acids. if these substances are in contact with the motile bacteria the following phenomena can be observed: at a certain toxin concentration the swarming of the bacteria is inhibited. if the concentration is increased the swarming ceases, and at still higher concentratio ... | 1987 | 3299877 |
| [characteristics of dissociation in cultures of aspergillus brasilense sp7]. | peculiarities of dissociation in the cultures of nitrogen-fixating soil microorganism azospirillum brasilense have been studied. the possible transfer among colony-morphology variants is established. the relations between variants are described by the following scheme: r in equilibrium with sr----s electrophoretic analysis of plasmid contents in different variants of azospirillum brasilense supposes the possible participation of plasmid dna in the dissociation process in this microorganism. | 1987 | 3683426 |
| penicillins, cephalosporins, and tetracyclines in treatment of hamsters with fatal leptospirosis. | a predictable 6- to 7-day course of a fatal leptospira interrogans serovar bataviae infection in experimentally infected mature 110- to 150-g hamsters was used to evaluate the therapeutic efficacy of conventionally used and newer antibiotics. active drugs were ampicillin, bacampicillin, cyclacillin, piperacillin, mezlocillin, doxycycline, chlortetracycline, cefotaxime, and moxalactam. cephalexin, cefadroxil, cefamandole, and cefoperazone showed little or no activity in preliminary studies. in de ... | 1986 | 3813511 |
| purification and properties of the nitrogenase of azospirillum amazonense. | the nitrogenase of the free-living, microaerobic, n2-fixing bacterium azospirillum amazonense (strain y1) was purified by chromatography on deae-52 cellulose, by heat treatment, and by preparative polyacrylamide gel electrophoresis. the specific nitrogenase activities were 2,400 nmol of c2h4 formed per min per mg of protein for dinitrogenase (mofe protein) and 1,800 nmol of c2h4 formed per min per mg of protein for dinitrogenase reductase (fe protein). the mofe protein was composed of a minimum ... | 1985 | 3864779 |
| flocculation in azospirillum brasilense and azospirillum lipoferum: exopolysaccharides and cyst formation. | the phenomena of flocculation and floc formation by azospirillum brasilense sp7 (atcc 29145) and azospirillum lipoferum sp59b (atcc 29707) were studied in aerobic liquid cultures. carbon sources representative of various entry pathways in combination with various nitrogen sources induced flocculation in both species of azospirilla. noticeably, the combination of fructose and nitrate was the most effective in terms of floc yields. phase-contrast microscopic observations revealed a transition in c ... | 1985 | 3894333 |
| salt tolerance of azospirillum brasilense. | the effect of various salts on the growth and n2-ase activity of azospirillum brasilense was tested. bicarbonate was found to be the most toxic, followed by chlorides and sulphate. tolerance of a. brasilense to these salts was comparable to that of many species of rhizobium. so4-- was stimulatory to growth and n2-ase activity up to 40 meq. the process of n2-fixation (n2-ase activity) was found to be more sensitive to all the salts tested as compared to growth. | 1985 | 3936328 |
| [plasmids of azospirillum brasilense]. | the cells from natural isolates of a. brasilense were found to harbour 1 to 4 plasmids with the molecular masses within the 27-300 md range. 100 md plasmids are specific for this bacterial species. strains isolated from the roots of cereals (wheat, maize, barley) have more heterogeneous plasmid composition as compared to the strains isolated from soil. | 1985 | 3939568 |
| nadph/nadh-dependent cold-labile glutamate dehydrogenase in azospirillum brasilense. purification and properties. | a cold-labile glutamate dehydrogenase (gdh, ec 1.4.1.3) has been purified to homogeneity from the crude extracts of azospirillum brasilense. the purified enzyme shows a dual coenzyme specificity, and both the nadph and nadh-dependent activities are equally cold-sensitive. the enzyme is highly specific for the substrates 2-oxoglutarate and glutamate. kinetic studies with gdh indicate that the enzyme is primarily designed to catalyse the reductive amination of 2-oxoglutarate. the nadp+-linked acti ... | 1986 | 3956501 |
| the virulence of clinical and environmental isolates of campylobacter jejuni. | the virulence of campylobacter jejuni and c. coli isolated from various water sources was compared with that of clinical strains by in vitro assays of adhesion, invasion and cytotoxicity to hela cells. variation in degree of attachment was observed, but this did not appear to be related to strain source, however, water strains were less invasive and less cytotoxic to hela cells than clinical strains as shown by immunofluorescence and electron microscopy. these differences were particularly evide ... | 1985 | 3973380 |
| purification and characterization of glutamate synthase from azospirillum brasilense. | growth conditions for azospirillum brasilense sp6 were devised for maximal expression of glutamate synthase. the enzyme levels were largely affected by the type and concentration of the nitrogen source. a 10-fold increase in the synthesis of the enzyme was observed at a limiting concentration of ammonia. the enzyme was purified to homogeneity by a procedure which was fairly rapid and allowed a good recovery of enzyme (30%). azospirillum glutamate synthase is a complex iron-sulfur flavoprotein wi ... | 1985 | 4019412 |
| heterologous hybridization of bacterial dna to the endoglucanases a and b structural genes cela and celb of clostridium thermocellum. | dna from various cellulolytic and non-cellulolytic bacteria was found to hybridize to clostridium thermocellum ncib10682 dna fragments carrying the structural genes cela and celb which code for endoglucanases a and b. homology to cela was detected in agrobacterium rhizogenes, azospirillum brasilense, bacillus subtilis, cellulomonas sp., clostridium stercorarium, erwinia chrysanthemi, pseudomonas solanacearum and streptomyces griseus. homology to celb was detected only in b. subtilis, c. stercora ... | 1985 | 4083831 |
| effect of dimethylsulfoxide on derepression of nitrogenase in spirillum lipoferum. | | 1981 | 6113164 |
| hydrogen metabolism of azospirillum brasilense in nitrogen-free medium. | production of h2 by azospirillum brasilense under n2-fixing conditions was studied in continuous and batch cultures. net h2 production was consistently observed only when the gas phase contained co. nitrogenase activity (c2h2 reduction) and h2 evolution (in the presence of 5% co) showed a similar response to o2 and were highest at 0.75% dissolved o2. uptake hydrogenase activity, ranging from 0.3 to 2.5 mumol h2/mg protein per hour was observed in batch cultures under n2. such rates were more tha ... | 1980 | 6257362 |
| hydrogenase activity in azospirillum brasilense is inhibited by nitrite, nitric oxide, carbon monoxide, and acetylene. | nitrite, no, co, and c2h2 inhibited o2-dependent h2 uptake (h3h oxidation) in denitrifying azospirillum brasilense sp7 grown anaerobically on n2o or no3-. the apparent ki values for inhibition of o2-dependent h2 uptake were 20 microm for no2-, 0.4 microm for no, 28 microm for co, and 88 microm for c2h2. these inhibitors also affected methylene blue-dependent h2 uptake, presumably by acting directly on the hydrogenase. nitrite and no inhibited h2 uptake irreversibly, whereas inhibition due to co ... | 1984 | 6384189 |
| [differentiation among species of the genus azospirillum]. | to replace the spirillum lipoferum denomination (2) for the nitrogen fixing group of soil spirilla, the azospirillum genus has been created in recent years (12), which includes two species: a. lipoferum and a. brasilense. both of them are nitrogen fixing bacteria able to induce a specific infection of grass roots (1, 6). consequently it is important to differentiate correctly the species when plant-bacteria relationships must be studied or inoculation assays must be carried out. for this reason ... | 1984 | 6400721 |
| [isolation of atmospheric-nitrogen-fixing spirilla from the waters of the paraná delta and other rivers]. | seventeen strains of spirillum-like organisms (2) were isolated from the parana delta and other rivers (table 1), using the following medium: 0.5% malic acid; 0.4% koh; 0.5% k2hpo4; 0.005% yeast extract; ph was adjusted to 7 with koh and 0.15% agar. the organisms produced a white, dense and sub-superficial pellicle in this medium, and streaking them on plates, single colonies could be isolated. they were easily recognized thanks to the congo red added to the medium, because the bacteria, as it h ... | 1984 | 6400725 |
| metabolism of various carbon sources by azospirillum brasilense. | azospirillum brasilense sp7 and two mutants were examined for 19 carbon metabolism enzymes. the results indicate that this nitrogen fixer uses the entner-doudoroff pathway for gluconate dissimilation, lacks a catabolic but has an anabolic embden-meyerhof-parnas hexosephosphate pathway, has amphibolic triosephosphate enzymes, lacks a hexose monophosphate shunt, and has lactate dehydrogenase, malate dehydrogenase, and glycerokinase. the mutants are severely deficient in phosphoglycerate and pyruva ... | 1983 | 6417113 |
| uptake of methionine sulfoximine by some n2 fixing bacteria, and its effect on ammonium transport. | the n2 fixing bacteria klebsiella pneumoniae, azospirillum brasilense, rhodopseudomonas sphaeroides and rhodospirillum rubrum, but not azotobacter vinelandii accumulate the glutamine analogue methionine sulfoximine in the cell. in the accumulating cells methionine sulfoximine inhibits ammonium transport. accumulation and inhibition are prevented by glutamine. | 1983 | 6418571 |
| intermediary carbon metabolism of azospirillum brasilense. | azospirillum brasilense sp 7 grew rapidly in azo medium containing reduced nitrogen and succinate as an energy source, with a doubling time of 43 min. no growth was measured with glucose as the sole carbon source. in contrast, azospirillum lipoferum sp 59b could grow in media containing either succinate or glucose with a doubling time of 69 min and 223 min, respectively. warburg-barcroft respirometry showed that the rate of oxygen consumption by a. brasilense sp 7 on glucose medium (0.034 mumol ... | 1984 | 6425263 |
| identification of a phosphoenolpyruvate:fructose 1-phosphotransferase system in azospirillum brasilense. | an inducible phosphoenolpyruvate:fructose phosphotransferase system has been detected in azospirillum brasilense, which requires a minimum of two components of the crude extracts for activity: (i) a soluble fraction (enzyme i) and (ii) a membrane fraction (enzyme ii). the uninduced cells neither show any uptake of fructose nor express activity of either of these two enzyme fractions. c-1 of fructose is the site of phosphorylation. this phosphotransferase system does not accept glucose as a subst ... | 1984 | 6501230 |
| catabolism of carbohydrates and organic acids and expression of nitrogenase by azospirilla. | fructose, galactose, l-arabinose, gluconate, and several organic acids support rapid growth and n2 fixation of azospirillum brasiliense atcc 29145 (strain sp7) as a sole source of carbon and energy. growth of azospirillum lipoferum atcc 29707 (strain sp59b) is also supported by glucose, mannose, mannitol, and alpha-ketoglutarate. oxidation of fructose and gluconate by a. brasiliense sp7 and of glucose, gluconate, and fructose by a. lipoferum sp59b was achieved through inducible enzymatic mechani ... | 1984 | 6588050 |
| uptake hydrogenase activity in denitrifying azospirillum brasilense grown anaerobically with nitrous oxide or nitrate. | zospirillum brasilense sp7 was grown anaerobically with n2o as the terminal electron acceptor and nh4cl as the nitrogen source. hydrogen uptake activity (o2-dependent h3h oxidation) was expressed in the presence and absence of 5% h2; it reached its maximum in late logarithmic phase as the malate became limiting. this activity was very stable in stationary phase, even in the absence of exogenous h2, compared with microaerobically grown cultures; this supports the hypothesis that the exclusion of ... | 1984 | 6690429 |
| fructose catabolism in azospirillum brasilense and azospirillum lipoferum. | the pathways for catabolism of fructose were investigated in the type strains of azospirillum lipoferum and azospirillum brasilense grown aerobically with (nh4)2so4 as the nitrogen source. when grown on fructose, the former species possessed a complete entner-doudoroff pathway, whereas the latter species lacked activity for glucose-6-phosphate dehydrogenase. both species possessed a complete catabolic embden-meyerhof-parnas pathway. neither species possessed the key enzyme of the hexose monophos ... | 1984 | 6735986 |
| an increase in nitrogen content of setaria italica and zea mays inoculated with azospirillum. | bacteria belonging to the genus azospirillum isolated from cynodon dactylon roots in israel were compared with azospirillum brasilense from brazil and california for their ability to fix nitrogen in association with grasses under greenhouse conditions. the plants were grown in a system which avoided cross inoculation from the inoculated soil to the control, while maintaining the natural soil microflora and humidity level in the soil close to field capacity. the organisms tested significantly inc ... | 1980 | 6769575 |
| characterization of a bacterium of the genus azospirillum from cellulolytic nitrogen-fixing mixed cultures. | a bacterium with the taxonomic characteristics of the genus azospirillum was isolated from celluloytic n2-fixing mixed cultures. its characteristics fit the descriptions of both azopirillum lipoferum (beijerinck) comb. nov. and azospirillum brasilense sp. nov. it may be a variant strain of a. lipoferum. in mixed cultures with cellulolytic organisms, the bacterium grew and fixed n2 with cellelose as a sole source of energy and carbon. the mixed cultures used cellulose from leaves of wheat (tritic ... | 1980 | 6773649 |