| synthesis and biological evaluation of new amino acids structurally related to the antitumor agent acivicin. | a set of racemic conformationally constrained analogues of the antitumor antibiotic acivicin (+)-1 has been prepared through a strategy based on 1,3-dipolar cycloaddition of bromonitrile oxide to suitable dipolarophiles. the bromo analogue (2) of acivicin was also synthesized and tested as a reference compound, together with its stereoisomer 3. the antitumor properties of novel amino acids 4-7 were evaluated in vitro against human tumor cell lines. their efficacy to inhibit glutamate synthase (g ... | 2003 | 13679161 |
| the development of azospirillum as a commercial inoculant for improving crop yields. | bacteria of the genus azospirillum are nitrogen-fixing organisms that live in close association with plants in the rhizosphere. the azospirillum-plant association leads to the enhanced development and yield of different host plants under appropriate growth conditions. this increase in yield is attributed mainly to an improvement in root development, an increase in the rate of water and mineral uptake by roots, and to a lesser extent, biological n(2) fixation. worldwide data accumulated in the fi ... | 1995 | 14536095 |
| indole-3-butyric acid (iba) production in culture medium by wild strain azospirillum brasilense. | some microorganisms found in the soil are able to produce substances which regulate plant growth. in this study, we show the presence of a substance associated with auxin activity, identified as indole-3-butyric acid (iba), in azospirillum brasilense uap 154 growth medium. a. brasilense was grown and indolic compounds were extracted from the supernatant. these were then analyzed by high performance liquid chromatography (hplc), gas chromatography and gas chromatography mass spectrometry. the ret ... | 2003 | 14638420 |
| model of bacterial band formation in aerotaxis. | aerotaxis is a particular form of "energy taxis". it is based on a largely elusive signal transduction machinery. in aerotaxis, oxygen dissolved in water plays the role of both attractant (at moderate concentrations) and repellent (at high and low concentrations). cells swimming from favorable oxygen concentrations into regions with unfavorable concentrations increase the frequency of reversals, turn back into the favorable domain, and become effectively trapped there. at the same time, bacteria ... | 2003 | 14645050 |
| microalgae growth-promoting bacteria as "helpers" for microalgae: a novel approach for removing ammonium and phosphorus from municipal wastewater. | a combination of microalgae (chlorella vulgaris or c. sorokiniana) and a microalgae growth-promoting bacterium (mgpb, azospirillum brasilense strain cd), co-immobilized in small alginate beads, was developed to remove nutrients (p and n) from municipal wastewater. this paper describes the most recent technical details necessary for successful co-immobilization of the two microorganisms, and the usefulness of the approach in cleaning the municipal wastewater of the city of la paz, mexico. a. bras ... | 2004 | 14675659 |
| in vitro uridylylation of the azospirillum brasilense n-signal transducing glnz protein. | azospirillum brasilense is a diazotroph which associates with important agricultural crops. the nitrogen fixation process in this organism is highly regulated by ammonium and oxygen, and involves several proteins including the two pii-like proteins, glnb and glnz. although these proteins are structurally very similar, they play different roles in the control of nitrogen fixation. in this work, we describe the expression, purification, and uridylylation of the glnz protein of a. brasilense strain ... | 2004 | 14680957 |
| characterization of cyst cell formation in the purple photosynthetic bacterium rhodospirillum centenum. | rhodospirillum centenum is an anoxygenic photosynthetic bacterium that is capable of differentiating into several cell types. when grown phototrophically in liquid, cells exhibit a vibrioid shape and have a single polar flagellum. when grown on a solid surface, r. centenum will differentiate into rod-shaped swarm cells that display numerous lateral flagella. upon starvation for nutrients, r. centenum also forms desiccation-resistant cysts. in this study, it was determined that r. centenum has he ... | 2004 | 14766916 |
| application of emission mössbauer spectroscopy to the study of cobalt coordination in the active centers of bacterial glutamine synthetase. | | 2003 | 14870610 |
| a method for studying insoluble immune complexes. | two variants of a method for determining the average composition of insoluble immune complex particles (iicp) are described. the first variant is based on measuring the specific turbidity (the turbidity per unit mass concentration of the dispersed substance) and the average size of iicp determined from dynamic light scattering (dls). in the second variant, the slope of the logarithmic turbidity spectrum (wavelength exponent) is used instead of dls particle size. both variants allow the average b ... | 2004 | 14980446 |
| disruption of dtdp-rhamnose biosynthesis modifies lipopolysaccharide core, exopolysaccharide production, and root colonization in azospirillum brasilense. | the interaction between azospirillum brasilense and plants is not fully understood, although several bacterial surface components like exopolysaccharides (eps), flagella, and capsular polysaccharides are required for attachment and colonization. while in other plant-bacteria associations (rhizobium-legume, pseudomonas-potato), lipopolysaccharides (lps) play a key role in the establishment of an effective association, their role in the root colonization by azospirillum had not been determined. in ... | 2004 | 14987774 |
| annotation of the prhico plasmid of azospirillum brasilense reveals its role in determining the outer surface composition. | the plant growth-promoting soil bacterium azospirillum brasilense enhances growth of economically important crops, such as wheat, corn and rice. in order to improve plant growth, a close bacterial association with the plant roots is needed. genes encoded on a 90-mda plasmid, denoted prhico plasmid, present in a. brasilense sp7, play an important role in plant root interaction. sequencing, annotation and in silico analysis of this 90-mda plasmid revealed the presence of a large collection of gene ... | 2004 | 15033235 |
| aromatic amino acid aminotransferase activity and indole-3-acetic acid production by associative nitrogen-fixing bacteria. | in this work, we report the detection of aromatic amino acid aminotransferase (aat) activity from cell-free crude extracts of nine strains of n(2)-fixing bacteria from three genera. using tyrosine as substrate, aat activity ranged in specific activity from 0.084 to 0.404 micromol min(-1)mg(-1). when analyzed under non-denaturating page conditions; and using tryptophan, phenylalanine, tyrosine, and histidine as substrates pseudomonas stutzeri a15 showed three isoforms with molecular mass of 46, 6 ... | 2004 | 15043864 |
| spectroscopic characterization of mineral crystals produced by the bacterium azospirillum brasilense. | the results of spectroscopic structural and trace elemental analyses of mineral crystals produced by the soil nitrogen-fixing bacterium azospirillum brasilense cultivated in a synthetic medium are presented and discussed. the mineral formed is shown to have a structure close to struvite (mgnh(4)po(4) x 6h(2)o; astm file no. 15-762) with some differences which may be attributed to the presence of isomorphic admixtures of other cations (struvite is known to have a variety of forms). aas/aes and io ... | 1996 | 15045359 |
| ultrastructure of interaction in alginate beads between the microalga chlorella vulgaris with its natural associative bacterium phyllobacterium myrsinacearum and with the plant growth-promoting bacterium azospirillum brasilense. | chlorella vulgaris, a microalga often used in wastewater treatment, was coimmobilized and coincubated either with the plant growth-promoting bacterium azospirillum brasilense, or with its natural associative bacterium phyllobacterium myrsinacearum, in alginate beads designed for advanced wastewater treatment. interactions between the microalga and each of the bacterial species were followed using transmission electron microscopy for 10 days. initially, most of the small cavities within the beads ... | 2001 | 15049443 |
| perchlorate-reducing microorganisms isolated from contaminated sites. | an extensive microcosm survey of perchlorate-contaminated sites was undertaken to assess the ability of indigenous microorganisms to degrade perchlorate. samples from 12 contaminated sites and from one pristine location were analysed. perchlorate was degraded to below detection limit in all electron donor-amended microcosms. perchlorate-reducing microorganisms (prms) were numerous at most of these sites. sixteen distinct prms were isolated that were phylogenetically related to either dechloromon ... | 2004 | 15049925 |
| [employment of associative bacteria for the inoculation of barley plants cultivated in soil contaminated with lead and cadmium]. | in laboratory experiments, the rhizobacteria azospirillum lipoferum 137, arthrobacter mysorens 7, agrobacterium radiobacter 10, and flavobacterium sp. l30 were found to have a relatively high resistance to the toxic heavy metals lead and cadmium (except that strain l30 was found to be sensitive to cd). when introduced by means of seed bacterization, the heavy metal-resistant strains actively colonized the rhizosphere of barley plants cultivated in uncontaminated and contaminated soils. in both p ... | 2004 | 15074051 |
| electrooptical analysis of the escherichia coli-phage interaction. | this article describes electrooptical (eo) characterization of biospecific binding between the bacterium escherichia coli xl-1 and the phage m13k07. the electrooptical analyzer (elus eo), which has been developed at the state research center for applied microbiology, obolensk, russia, was used as the basic instrument for eo measurements. the operating principle of the analyzer is based on the polarizability of microorganisms, which depends strongly on their composition, morphology, and phenotype ... | 2004 | 15113695 |
| structural characterization of glutamine synthetase from azospirillum brasilense. | cd spectroscopic study of the secondary structure of partly adenylylated glutamine synthetase (gs) of the bacterium azospirillum brasilense showed both the native and cation-free (edta-treated) enzyme to be highly structured (58 and 49% as alpha-helices, 10 and 20% as beta-structure, respectively). mg(2+), mn(2+), or co(2+), when added to the native gs, had little effect on its cd spectrum, whereas their effects on the cation-free gs were more pronounced. emission ((57)co) mössbauer spectroscopi ... | 2004 | 15137096 |
| studies of listeria monocytogenes-antibody binding using electro-orientation. | an electro-optical (eo) approach has been used for studies of listeria monocytogenes-antibody binding. the eo analyzer, which has been developed at the state research center for applied microbiology, obolensk, was used as a basic instrument for eo measurements. ac electro-kinetic effects depend on dielectric properties of bioparticles, their composition, morphology, the medium, and the frequency of applied electrical field. electro-orientational spectra were used for discrimination of bacteria b ... | 2004 | 15142611 |
| azospirillum irakense pectate lyase displays a toroidal fold. | the three-dimensional structure of azospirillum irakense pectate lyase (pela) has been determined at a resolution of 2.65 a. the crystals are hexagonal, belonging to space group p6(5)22, with unit-cell parameters a = b = 85.37, c = 231.32 angstroms. phase information was derived from a multiple-wavelength anomalous dispersion (mad) experiment using a hg derivative. refinement of the model converged to rcryst = 20.08% and rfree = 25.87%. the overall structure of pela does not adopt the characteri ... | 2004 | 15159558 |
| isolation, characterization and beneficial effects of rice associated plant growth promoting bacteria from zanzibar soils. | this study was undertaken to isolate and characterize plant growth promoting bacteria (pgpb) occurring in four soils of zanzibar, tanzania as well as to evaluate their potential use as biofertilizers for rice. a total of 12 pgpb strains were isolated from rice and studied for growth characteristics, carbon/nitrogen source utilization patterns using qts-24 kits, phosphate solubilization, indole acetic acid (iaa) production, antibiotic resistance patterns and growth at different ph, temperature an ... | 2004 | 15162398 |
| dual flagellar systems enable motility under different circumstances. | flagella are extremely effective organelles of locomotion used by a variety of bacteria and archaea. some bacteria, including aeromonas, azospirillum, rhodospirillum, and vibrio species, possess dual flagellar systems that are suited for movement under different circumstances. swimming in liquid is promoted by a single polar flagellum. swarming over surfaces or in viscous environments is enabled by the production of numerous peritrichous, or lateral, flagella. the polar flagellum is produced con ... | 2004 | 15170400 |
| [a comparison of the lipopolysaccharides and o-specific polysaccharides of azospirillum brasilense sp245 and its omegon-km mutants km018 and km252]. | the lipopolysaccharides (lpss) extracted from the outer membrane of azospirillum brasilense sp245 and its omegon-km mutants km018 and km252 with a hot aqueous solution of phenol were found to differ in the content of carbohydrates, glucosamine, and total phosphorus and in the proportion of octadecenoic and hexadecanoic acids in the lipid moieties of the lpss. the carbohydrate moieties of the lpss were heterogeneous in charge. the analysis of the o-specific polysaccharides (o-pss) of the mutants ... | 2004 | 15198028 |
| molecular and physiological comparison of azospirillum spp. isolated from rhizoctonia solani mycelia, wheat rhizosphere, and human skin wounds. | four phenotypically similar bacterial strains isolated from fungal, plant, and human sources were identified as azospirillum species. strains rc1 and lod4 were isolated from the mycelium of the apple root pathogen rhizoctonia solani ag 5 and from the rhizosphere of wheat grown in apple orchard soil, respectively. strains c610 and f4626 isolated from human wounds were previously misclassified as roseomonas genomospecies 3 and 6. all four strains demonstrated close similarities in 16s rrna gene se ... | 2004 | 15213753 |
| evaluation of fly ash as a carrier for diazotrophs and phosphobacteria. | fly ash and its different combinations with soil (w/w) were tested to explore its possible use as a potential carrier for diazotrophs and phosphobacteria. azotobacter chroococcum, azospirillum brasilense and bacillus circulans showed their maximum viability in fly ash alone whereas pseudomonas striata proliferated most in soil:fly ash (1:1) combination. | 2004 | 15246443 |
| effects of plant growth promoting bacteria and composed organic fertilizers on the reproduction of meloidogyne incognita and tomato growth. | glasshouse experiments were conducted to assess the influence of pseudomonas fluorescens, azotobacter chroococcum, azospirillum brasilense and composted organic fertilizers (cow dung, horse dung, goat dung and poultry manure) alone and in combination on the multiplication of meloidogyne incognita and growth of tomato. p. fluorescens was better at improving tomato growth and reducing galling and nematode multiplication than a. chroococcum or a. brasilense. among composted organic fertilizers, pou ... | 2004 | 15246448 |
| glnb is specifically required for azospirillum brasilense nifa activity in escherichia coli. | the azospirillum brasilense transcription regulator nifa and the nitrogen-status signaling proteins glnb, glnz and glnk were expressed in escherichia coli and analyzed for their ability to activate nif gene expression. when expressed separately, none of the proteins were able to activate nifh promoter expression in any tested conditions; in contrast, nifh expression was observed in cells grown in the absence of ammonium and oxygen and when expressing simultaneously nifa and glnb proteins, but no ... | 2004 | 15249067 |
| construction of a reca mutant of azospirillum lipoferum and involvement of reca in phase variation. | the plant-growth promoting rhizobacterium azospirillum lipoferum strain 4b generates in vitro a stable phase variant designated 4vi at frequencies of 10(-4) to 10(-3) per cell per generation. variant 4vi displays pleitropic modifications, such as the loss of swimming motility and the inability to assimilate certain sugars compared to the wild type. the mechanism underlying phase variation is unknown. to determine whether reca-mediated processes are involved in phase variation, the reca gene of a ... | 2004 | 15251210 |
| associative diazotrophs of pearl millet (pennisetum glaucum) from semi arid region--isolation and characterization. | diversity of the native diazotrophs associated with the rhizosphere of pearl millet (p. glaucumn), grown in nutritionally poor soils of semi-arid regions was studied with a view to isolate effective nitrogen fixing and plant growth stimulating bacteria with root associative characteristics. the native population varied from 10(3)-10(4) g(-1) of rhizosphere soil after 40 d growth and belonged to genera azospirillum, azotobacter and klebsiella. another non-diazotrophic root associative group was p ... | 2003 | 15255644 |
| extended phenotype of an mreb-like mutant in azospirillum brasilense. | tn5 mutagenesis was used to generate an azospirillum brasilense spf94 mutant. genetic analysis of this mutant revealed that a homologue of the mreb gene, which controls cell shape in bacillus subtilis and escherichia coli, was inactivated. the cell-surface properties of the mutant were different from those of the parental strain. the mutant colonies were highly fluorescent when grown on plates containing calcofluor white. light and electron microscopy revealed that the mutant cells were round an ... | 2004 | 15256588 |
| monitoring of cobalt(ii) uptake and transformation in cells of the plant-associated soil bacterium azospirillum brasilense using emission mössbauer spectroscopy. | interaction of cobalt(ii) at micromolar concentrations with live cells of the plant-growth-promoting rhizobacterium azospirillum brasilense (strain sp245) and further transformations of the metal cation were monitored using 57co emission mössbauer spectroscopy (ems). cell suspensions of the bacterial culture (2.4 x 10(8) cells ml(-1)) were doped with radioactive 57cocl2 (1 mci; final concentration 2 x 10(-6) m 57co2+), kept under physiological conditions for various periods of time (from 2 min u ... | 2004 | 15259367 |
| arabinose content of extracellular polysaccharide plays a role in cell aggregation of azospirillum brasilense. | extracellular polysaccharides play an important role in aggregation and surface colonization of plant-associated bacteria. in this work, we report the time course production and monomer composition of the exopolysaccharide (eps) produced by wild type strain and several mutants of the plant growth promoting rhizobacterium (pgpr) azospirillum brasilense. in a fructose synthetic medium, wild type strain sp7 produced a glucose-rich eps during exponential phase growth and an arabinose-rich eps during ... | 2004 | 15321662 |
| possible roles of nitrogen fixation and mineral uptake induced by rhizobacterial inoculation on salt tolerance of maize. | pot experiments were conducted to evaluate the possible roles of nitrogen fixation and/or enhanced mineral uptake by azospirillum lipoferum and bacillus polymexa inoculation in improving salt tolerance of maize plants. plants were inoculated and grown under salt stress (osmotic potential: -0.3, -0.6, -0.9 and -1.2 mpa). both microorganisms were able to fix nitrogen up to -0.9 mpa salinity level accompanied with increased total n-yield compared with the control plants. in order to investigate the ... | 2004 | 15330268 |
| [single insertions of omegon into azospirillum brasilense dna result in defects in the bacterial mobility of several types]. | | 2004 | 15354940 |
| an energy taxis transducer promotes root colonization by azospirillum brasilense. | motility responses triggered by changes in the electron transport system are collectively known as energy taxis. in azospirillum brasilense, energy taxis was shown to be the principal form of locomotor control. in the present study, we have identified a novel chemoreceptor-like protein, named tlp1, which serves as an energy taxis transducer. the tlp1 protein is predicted to have an n-terminal periplasmic region and a cytoplasmic c-terminal signaling module homologous to those of other chemorecep ... | 2004 | 15375141 |
| transfer of a plant chitinase gene into a nitrogen-fixing azospirillum and study of its expression. | azospirillum is used extensively in rice and other cereal crops as a biofertilizer. there is a substantial opportunity to improve the efficiency of this bacterium through the transfer of genes of agricultural importance from other organisms. chitinases are antifungal proteins, and expression of chitinase genes in azospirillum would help to develop strains with potential antifungal activities. so far there are no reports about transfer of plant genes into azospirillum and their expression. the pr ... | 2004 | 15381976 |
| the electron transfer flavoprotein fixabcx gene products from azospirillum brasilense show a nifa-dependent promoter regulation. | the complete nucleotide sequence of the a. brasilense fixa, fixb, fixc, and fixx genes is reported here. sequence similarities between the protein sequences deduced from fixabcx genes and many electron transfer flavoproteins (etfs) have been noted. comparison of the amino acid sequences of both subunits of etf with the a. brasilense fixa and fixb gene products exhibits an identity of 30%. the amino acid sequence of the other two genes, fixc and fixx, revealed similarity with the membrane-bound e ... | 2004 | 15386115 |
| repressor mutant forms of the azospirillum brasilense ntrc protein. | the azospirillum brasilense mutant strains fp8 and fp9, after treatment with nitrosoguanidine, showed a null nif phenotype and were unable to use nitrate as their sole nitrogen source. sequencing of the ntrc genes revealed single nucleotide mutations in the ntrc nucleotide-binding site. the phenotypes of these strains are discussed in relation to their genotypes. | 2004 | 15466584 |
| azospirillum-plant relationships: physiological, molecular, agricultural, and environmental advances (1997-2003). | this review presents a critical and comprehensive documentation and analysis of the developments in agricultural, environmental, molecular, and physiological studies related to azospirillum cells, and to azospirillum interactions with plants, based solely on information published between 1997 and 2003. it was designed as an update of previous reviews (bashan and levanony 1990; bashan and holguin 1997a), with a similar scope of interest. apart from an update and critical analysis of the current k ... | 2004 | 15467782 |
| molecular dynamics simulation of the interaction between the complex iron-sulfur flavoprotein glutamate synthase and its substrates. | glutamate synthase (glts) is a complex iron-sulfur flavoprotein that catalyzes the reductive transfer of l-glutamine amide group to the c2 carbon of 2-oxoglutarate yielding two molecules of l-glutamate. molecular dynamics calculations in explicit solvent were carried out to gain insight into the conformational flexibility of glts and into the role played by the enzyme substrates in regulating the catalytic cycle. we have modelled the free (unliganded) form of azospirillum brasilense glts alpha s ... | 2004 | 15498940 |
| gluconic acid production and phosphate solubilization by the plant growth-promoting bacterium azospirillum spp. | in vitro gluconic acid formation and phosphate solubilization from sparingly soluble phosphorus sources by two strains of the plant growth-promoting bacteria a. brasilense (cd and 8-i) and one strain of a. lipoferum ja4 were studied. strains of a. brasilense were capable of producing gluconic acid when grown in sparingly soluble calcium phosphate medium when their usual fructose carbon source is amended with glucose. at the same time, there is a reduction in ph of the medium and release of solub ... | 2004 | 15502903 |
| molecular and functional characteristics, growth promoting effect and persistence of selected parent isolates and streptomycin resistant derivatives of rice rhizobacteria. | molecular and functional characteristics of seven azospirilla and five phosphorus solubilizing bacteria (psb) isolates of rice rhizosphere, growth promotion ability of two efficient strains, azospirillum amazonense a10 (mtcc4716) and bacillus megaterium p5 (mtcc4714) and their persistence based on streptomycin resistant derivatives (srd), were determined. sds-page and isozyme banding patterns of the isolates were used to arbitrarily group the azospirilla into 4 and psb into 3 clusters and as mar ... | 2004 | 15623229 |
| [function and application of soil microorganisms in forest ecosystem]. | soil microorganism is an important part of forest ecosystem, and plays an important role in sustainable development of forestry. in this paper, we summarized the main functions of soil microorganisms in forest sustainable development from the aspects of 1) the role of soil microorganism and microbiomass; 2) the function of mycorrhizal fungi; 3) the impact of pathogen; and 4) the effect of pgpr. finally, we also discussed the research trends of forest soil microorganism and its application. some ... | 2004 | 15624841 |
| influence of substrate composition and flow rate on growth of azospirillum brasilense cd in a co-culture with 3 sorghum rhizobacteria. | the ability of azospirillum brasilense cd to colonize the niche occupied by 3 bacterial strains previously isolated from sorghum rhizosphere was studied by means of the biolog system. the isolates were identified by different methods as strains belonging to pseudomonas putida, stenotrophomonas maltophilia, and klebsiella terrigena species. several c sources, also chosen among the constituents of sorghum root exudates, were used to evaluate the metabolic profiles of azospirillum and the sorghum r ... | 2004 | 15644901 |
| carbapenem antibiotic biosynthesis in erwinia carotovora is regulated by physiological and genetic factors modulating the quorum sensing-dependent control pathway. | erwinia carotovora produces the beta-lactam antibiotic, carbapenem, in response to a quorum sensing signalling molecule, n-(3-oxohexanoyl)-l-homoserine lactone (ohhl). we have mapped the ohhl-dependent promoter upstream of the first of the biosynthetic genes, cara. we have also analysed the effect on this promoter of the known genetic regulators of carbapenem expression, carr, cari (encoding homologues of luxr and luxi respectively) and hor (encoding a slya/marr-like transcriptional regulator). ... | 2005 | 15659168 |
| [a comparative study of the effect of the lectins of azospirillum brasilense sp7 and its mutant on the activity of some enzymes in plant cells]. | | 2004 | 15688946 |
| effects of over-expression of the regulatory enzymes drat and drag on the ammonium-dependent post-translational regulation of nitrogenase reductase in azospirillum brasilense. | nitrogen fixation in azospirillum brasilense is regulated at transcriptional and post-translational levels. post-translational control occurs through the reversible adp-ribosylation of dinitrogenase reductase (fe protein), mediated by the dinitrogenase reductase adp-ribosyltransferase (drat) and dinitrogenase reductase glycohydrolase (drag). although the drat and drag activities are regulated in vivo, the molecules responsible for such regulation remain unknown. we have constructed broad-host-ra ... | 2005 | 15723223 |
| physical organization of phytobeneficial genes nifh and ipdc in the plant growth-promoting rhizobacterium azospirillum lipoferum 4vi. | the physical organization of phytobeneficial genes was investigated in the plant growth-promoting rhizobacterium azospirillum lipoferum 4vi by hybridization screening of a bacterial artificial chromosome (bac) library. pulsed-field gel electrophoresis gave an estimated 5.7-mb genome size for strain 4vi and a coverage level of 9 for the bac library. the phytobeneficial genes nifh (associative nitrogen fixation) and ipdc (synthesis of the phytohormone indoleacetic acid) are chromosomal, but no bac ... | 2005 | 15727835 |
| structure of the o-polysaccharide from the azospirillum lipoferum sp59b lipopolysaccharide. | a neutral o-specific polysaccharide was obtained by mild acid hydrolysis of the lipopolysaccharide of the plant-growth-promoting bacterium azospirillum lipoferum sp59b. on the basis of sugar and methylation analyses along with 1d and 2d (1)h and (13)c nmr spectroscopy, including a noesy experiment, the following structure of the branched hexasaccharide repeating unit of the o-polysaccharide was established: [carbohydrate structure: see text]. | 2005 | 15797145 |
| the unexpected structural role of glutamate synthase [4fe-4s](+1,+2) clusters as demonstrated by site-directed mutagenesis of conserved c residues at the n-terminus of the enzyme beta subunit. | azospirillum brasilense glutamate synthase (glts) is a complex iron-sulfur flavoprotein whose catalytically active alphabeta protomer (alpha subunit, 162kda; beta subunit, 52.3 kda) contains one fad, one fmn, one [3fe-4s](0,+1), and two [4fe-4s](+1,+2) clusters. the structure of the alpha subunit has been determined providing information on the mechanism of ammonia transfer from l-glutamine to 2-oxoglutarate through a 30 a-long intramolecular tunnel. on the contrary, details of the electron tran ... | 2005 | 15797248 |
| isolation and characterization of a diazotrophic, oxalate-oxidizing bacterium from sour grass (oxalis pes-caprae l.). | a new type of nitrogen-fixing, oxalate-oxidizing azospirillum sp. was isolated from the roots of oxalis pes-caprae. polyphasic taxonomy was performed, including auxanography using api galleries, physiological tests and 16s rrna sequence comparison. optimum growth occurred at 30 degrees c, ph 7.5. growth was observed at 37 and 42 degrees c with oxalate and in the presence of 3-4% nacl and 2% potassium oxalate. in liquid culture, the doubling time (t(d)) with oxalate was 9 h. its closest phylogene ... | 2005 | 15808950 |
| azospirillum brasilense produces the auxin-like phenylacetic acid by using the key enzyme for indole-3-acetic acid biosynthesis. | an antimicrobial compound was isolated from azospirillum brasilense culture extracts by high-performance liquid chromatography and further identified by gas chromatography-mass spectrometry as the auxin-like molecule, phenylacetic acid (paa). paa synthesis was found to be mediated by the indole-3-pyruvate decarboxylase, previously identified as a key enzyme in indole-3-acetic acid (iaa) production in a. brasilense. in minimal growth medium, paa biosynthesis by a. brasilense was only observed in ... | 2005 | 15812004 |
| enhanced swarming of bacteria on agar plates containing the surfactant tween 80. | a widely used method for quantifying swarming motility is the swarm plate assay. a significant increase in the motility halo size formed by escherichia coli or azospirillum brasilense was measured on tween 80-containing agar relative to untreated agar. this improvement could benefit the identification of mutants in swarming motility. | 2005 | 15823402 |
| nitric oxide is involved in the azospirillum brasilense-induced lateral root formation in tomato. | azospirillum spp. is a well known plant-growth-promoting rhizobacterium. azospirillum-inoculated plants have shown to display enhanced lateral root and root hair development. these promoting effects have been attributed mainly to the production of hormone-like substances. nitric oxide (no) has recently been described to act as a signal molecule in the hormonal cascade leading to root formation. however, data on the possible role of no in free-living diazotrophs associated to plant roots, is unav ... | 2005 | 15824907 |
| liberation of amino acids by heterotrophic nitrogen fixing bacteria. | large amounts of amino acids are produced by nitrogen-fixing bacteria such as azotobacter, azospirillum, rhizobium, mesorhizobium and sinorhizobium when growing in culture media amended with different carbon and nitrogen sources. this kind of bacteria live in close association with plant roots enhanced plant growth mainly as a result of their ability to fix nitrogen, improving shoot and root development suppression of pathogenic bacteria and fungi, and increase of available p concentration. also ... | 2005 | 15827688 |
| transcriptional analysis of the azospirillum brasilense indole-3-pyruvate decarboxylase gene and identification of a cis-acting sequence involved in auxin responsive expression. | expression of the azospirillum brasilense ipdc gene, encoding an indole-3-pyruvate decarboxylase, a key enzyme in the production of indole-3-acetic acid (iaa) in this bacterium, is upregulated by iaa. here, we demonstrate that the ipdc gene is the promoter proximal gene in a bicistronic operon. database searches revealed that the second gene of this operon, named iaac, is well conserved evolutionarily and that the encoded protein is homologous to the escherichia coli protein scrp-27a, the zebraf ... | 2005 | 15828683 |
| [investigation of electrophysical properties of listeria monocytogenes cells during the interaction with monoclonal antibodies]. | an electrooptical approach was used in studies of listeria monocytogenes-antibody binding. an electrooptical analyzer, which has been developed at the state research center for applied microbiology (obolensk, russia), was used as a basic instrument for electrooptical measurements. the analyzer consists of the following modules: a sample preparation module, a mixer, an ac field generator, an eo-flow cell, a microcontroller for transfer of liquid, a thermal system, an operator interface, and an im ... | 2005 | 15856991 |
| growth and indole-3-acetic acid biosynthesis of azospirillum brasilense sp245 is environmentally controlled. | batch and fed batch cultures of azospirillum brasilense sp245 were conducted in a bioreactor. growth response, iaa biosynthesis and the expression of the ipdc gene were monitored in relation to the environmental conditions (temperature, availability of a carbon source and aeration). a. brasilense can grow and produce iaa in batch cultures between 20 and 38 degrees c in a standard minimal medium (mmab) containing 2.5 gl(-1)l-malate and 50 microgml(-1) tryptophan. iaa synthesis requires depletion ... | 2005 | 15869971 |
| functional analysis of the gaf domain of nifa in azospirillum brasilense: effects of tyr-->phe mutations on nifa and its interaction with glnb. | regulation of nifa activity in azospirillum brasilense depends on glnb (a pii protein), and it was previously reported that the target of glnb activity is the n-terminal domain of nifa. furthermore, mutation of the tyr residue at position 18 in the n-terminal domain resulted in a nifa protein that did not require glnb for activity under nitrogen fixation conditions. we report here that a nifa double mutant in which the tyr residues at positions 18 and 53 of nifa n-were simultaneously replaced by ... | 2005 | 15887032 |
| [the electrooptical parameters of suspensions of escherichia coli xl-1 cells interacting with helper phage m13k07]. | the electrophysical properties of escherichia coli xl-1 cells interacting with helper phage m13k07 were studied as a function of the phage-to-cell ratio and the contact time. the electro-optical signal of bacterial cells changed considerably as soon as 10 min after the onset of their incubation with phage particles, presumably due to phage adsorption on the cell surface. the maximum changes in the orientational spectra of cell suspensions were observed when the phage-to-cell ratio was 20. select ... | 2005 | 15938396 |
| [analysis of dna, lipopolysaccharide structure, and some cultural and morphological properties in closely related strains of azospirillum brasilense]. | we studied closely related azospirillum brasilense strains sp7 and cd. for probing of their genomes, the fragments of 85-mda (p85) and 120-mda (p120) from a. brasilense sp245 plasmids were hybridized with 115-mda (p115) and 90-mda (p90) plasmids of strain sp7, respectively. strain cd was found to lose the 115-mda plasmid and one of the two ecori restriction fragments of the total dna (localized within p115 and the chromosome) that was homologous to an ecori-generated p85 fragment of 2.4 kb. on t ... | 2005 | 15938399 |
| isolation of transposon mutants from azospirillum brasilense yu62 and characterization of genes involved in indole-3-acetic acid biosynthesis. | the molecular genetics of indole-3-acetic (iaa) synthesis and regulation in azospirillum brasilense was investigated in this study. tn5 mutagenesis was performed and five mutants with decreased iaa production were isolated. five tn5-inserted genes from these mutants were cloned and sequenced. four genes were reported for the first time to be involved in iaa production, namely, atra, ftsa, omaa and alda that code for gntr-family transcriptional regulator, iron-binding protein component of abc-typ ... | 2005 | 15961260 |
| image analysis for quantification of bacterial rock weathering. | a fast, quantitative image analysis technique was developed to assess potential rock weathering by bacteria. the technique is based on reduction in the surface area of rock particles and counting the relative increase in the number of small particles in ground rock slurries. this was done by recording changes in ground rock samples with an electronic image analyzing process. the slurries were previously amended with three carbon sources, ground to a uniform particle size and incubated with rock ... | 2006 | 15982765 |
| reduction of perchlorate and nitrate by microbial communities in vadose soil. | perchlorate contamination is a concern because of the increasing frequency of its detection in soils and groundwater and its presumed inhibitory effect on human thyroid hormone production. although significant perchlorate contamination occurs in the vadose (unsaturated) zone, little is known about perchlorate biodegradation potential by indigenous microorganisms in these soils. we measured the effects of electron donor (acetate and hydrogen) and nitrate addition on perchlorate reduction rates an ... | 2005 | 16000806 |
| azospirillum oryzae sp. nov., a nitrogen-fixing bacterium isolated from the roots of the rice plant oryza sativa. | the taxonomic position of the free-living diazotrophic strain coc8(t) isolated from rice was investigated based on phylogenetic analyses. 16s rrna gene sequence analyses indicated that strain coc8(t) was closely related to the genus azospirillum (96% similarity). chemotaxonomic characteristics (g+c content of the dna 66.8 mol%, q-10 quinone system, 18:1omega7c as the major fatty acid and 14:0 3-oh and 16:0 3-oh as the major hydroxy fatty acids) were also similar to those of the genus azospirillu ... | 2005 | 16014463 |
| the effect of native and acc deaminase-containing azospirillum brasilense cd1843 on the rooting of carnation cuttings. | carnation cuttings treated with non-transformed and 1-aminocyclopropane (acc) deaminase-containing azospirillum brasilense cd1843 produced significantly more roots than untreated controls and fewer roots than cuttings treated with 0.1% indolebutyric acid (iba). the roots produced by cuttings treated with acc deaminase-containing azospirillum brasilense cd1843 were the longest roots resulting from any of the treatments, followed by non-transformed azospirillum brasilense cd1843, 0.1% iba, and tre ... | 2005 | 16121231 |
| history on the biological nitrogen fixation research in graminaceous plants: special emphasis on the brazilian experience. | this review covers the history on biological nitrogen fixation (bnf) in graminaceous plants grown in brazil, and describes research progress made over the last 40 years, most of which was coordinated by johanna döbereiner. one notable accomplishment during this period was the discovery of several nitrogen-fixing bacteria such as the rhizospheric (beijerinckia fluminensis and azotobacter paspali), associative (azospirillum lipoferum, a. brasilense, a. amazonense) and the endophytic (herbaspirillu ... | 2005 | 16127558 |
| nitrogenase switch-off by ammonium ions in azospirillum brasilense requires the glnb nitrogen signal-transducing protein. | nitrogenase activity in several diazotrophs is switched off by ammonium and reactivated after consumption. the signaling pathway to this system in azospirillum brasilense is not understood. we show that ammonium-dependent switch-off through adp-ribosylation of fe protein was partial in a glnb mutant of a. brasilense but absent in a glnb glnz double mutant. triggering of inactivation by anaerobic conditions was not affected in either mutant. the results suggest that glnb is necessary for full amm ... | 2005 | 16151168 |
| defluvicoccus vanus gen. nov., sp. nov., a novel gram-negative coccus/coccobacillus in the 'alphaproteobacteria' from activated sludge. | a novel gram-negative coccus/coccobacillus, strain ben 114(t), growing in tetrads, clusters or aggregates, was isolated from activated sludge by micromanipulation. 16s rrna gene sequence analysis revealed that it belonged to the 'alphaproteobacteria', with no close relatives among cultured bacterial isolates. on the basis of phylogenetic data, this organism is considered to belong to a new genus, defluvicoccus, represented by the species defluvicoccus vanus sp. nov., a name chosen because of the ... | 2005 | 16166717 |
| inoculation with the plant-growth-promoting rhizobacterium azospirillum brasilense causes little disturbance in the rhizosphere and rhizoplane of maize (zea mays). | inoculation with azospirillum brasilense exerts beneficial effects on plant growth and crop yields. in this study, a comparative analysis of maize (zea mays) root inoculated or not inoculated with a. brasilense strains was performed in two soils. colonization dynamics of the rhizobacteria were tracked in various root compartments using 16s rrna-targeted probes and 4',6'diamidino-2-phenylindole staining, and the structure of bacterial populations in the same samples was analyzed by denaturing gra ... | 2005 | 16211327 |
| [plasmid rearrangements in azospirillum brasilense]. | | 2005 | 16211863 |
| [extracellular proteolytic enzymes of azospirillum brasilensis strain sp7 and regulation of their activity by a homologous lectin]. | it was found that azospirillum brasilensis strain sp7 is able to produce extracellular proteolytic enzymes. the enzymes were active within a broad range of ph values, with two peaks of activity being located in the acid and alkaline ph areas; required calcium ions; and exhibited substrate specificity with respect to azogelatin. zymography allowed at least four proteolytic enzymes with molecular weights of 32, 45, 52, and 174 kda to be detected in a. brasilense sp7 culture liquid. it was shown th ... | 2005 | 16212042 |
| bacterial diversity in the rhizosphere of proteaceae species. | the cape floral kingdom is an area of unique plant biodiversity in south africa with exceptional concentrations of rare and endemic species and experiencing drastic habitat loss. here we present the first molecular study of the microbial diversity associated with the rhizosphere soil of endemic plants of the proteaceae family (leucospermum truncatulum and leucadendron xanthoconus). genomic dna was extracted from l. truncatulum rhizosphere soil, l. xanthoconus rhizosphere and non-rhizosphere soil ... | 2005 | 16232290 |
| the nodpq genes in azospirillum brasilense sp7 are involved in sulfation of lipopolysaccharides. | here we report on the presence of sulfated lipopolysaccharide molecules in azospirillum brasilense, a plant growth-promoting rhizosphere bacterium. chemical analysis provided structural data on the o-antigen composition and demonstrated the possible involvement of the nodpq genes in o-antigen sulfation. | 2005 | 16232291 |
| comparative in situ analysis of ipdc-gfpmut3 promoter fusions of azospirillum brasilense strains sp7 and sp245. | inoculation of wheat roots with azospirillum brasilense results in an increase of plant growth and yield, which is proposed to be mainly due to the bacterial production of indole-3-acetic acid in the rhizosphere. field inoculation experiments had revealed more consistent plant growth stimulation using a. brasilense strain sp245 as compared with the strain sp7. therefore, the in situ expression of the key gene ipdc (indole-3-pyruvate decarboxylase) was examined in these two strains. within the ip ... | 2005 | 16232298 |
| azospirillum brasilense does not affect population structure of specific rhizobacterial communities of inoculated maize (zea mays). | positive response of plant species to plant growth-promoting rhizobacteria have led to an increased interest in their use as bacterial inoculants. however, the introduction of exogenous bacteria into natural ecosystems may perturb bacterial populations within the microbial community and lead to the disruption of indigenous populations performing key functional roles. in this study the effect of azospirillum brasilense inoculation on maize (zea mays) rhizosphere actinobacteria, bacteroidetes, alp ... | 2005 | 16232299 |
| effect of the over-expression of pii and pz proteins on the nitrogenase activity of azospirillum brasilense. | the azospirillum brasilense pii and pz proteins, encoded by the glnb and glnz genes respectively, are intracellular transducers of nitrogen levels with distinct functions. the pii protein participates in nif regulation by controlling the activity of the transcriptional regulator nifa. pii is also involved in transducing the prevailing nitrogen levels to the fe-protein adp-ribosylation system. pz regulates negatively ammonium transport and is involved in nitrogenase reactivation. to further inves ... | 2005 | 16239079 |
| effects of heavy metals on plant-associated rhizobacteria: comparison of endophytic and non-endophytic strains of azospirillum brasilense. | the plant-associated nitrogen-fixing rhizobacterium azospirillum brasilense attracts world-wide attention owing to its plant growth-promoting activities. among hundreds of its strains known up to date, wild-type strain sp245 has been proved to be capable of colonising both the plant-root interior and exterior (i.e. a facultative endophyte), whereas others are non-endophytes colonising the root surface only. thus, the different ecological niches occupied by these strains in the rhizosphere sugges ... | 2005 | 16240678 |
| bacterial community dynamics and polycyclic aromatic hydrocarbon degradation during bioremediation of heavily creosote-contaminated soil. | bacterial community dynamics and biodegradation processes were examined in a highly creosote-contaminated soil undergoing a range of laboratory-based bioremediation treatments. the dynamics of the eubacterial community, the number of heterotrophs and polycyclic aromatic hydrocarbon (pah) degraders, and the total petroleum hydrocarbon (tph) and pah concentrations were monitored during the bioremediation process. tph and pahs were significantly degraded in all treatments (72 to 79% and 83 to 87%, ... | 2005 | 16269736 |
| [determination of the structure of the repeated unit of the azospirillum brasilense sr75 o-specific polysaccharide and homology of the lps loci in the plasmids of azospirillum brasilense strains sr75 and sp245]. | the structural identity of the repeated unit in o-specific polysaccharides (opss) present in the outer membrane of strain sr75 of the bacterium azospirillum brasilense, isolated from wheat rhizosphere in saratov oblast, and the opss of previously studied a. brasilense strain sp245, isolated from surface-sterilized wheat roots in brazil, has been demonstrated. plasmid profiles, dna restriction, and hybridization assays suggested that a. brasilense strains sr75 and sp245 have different genomic str ... | 2005 | 16315981 |
| cloning, expression, and characterization of bacterial l-arabinose 1-dehydrogenase involved in an alternative pathway of l-arabinose metabolism. | azospirillum brasiliense converts l-arabinose to alpha-ketoglutarate via five hypothetical enzymatic steps. we purified and characterized l-arabinose 1-dehydrogenase (ec 1.1.1.46), catalyzing the conversion of l-arabinose to l-arabino-gamma-lactone as an enzyme responsible for the first step of this alternative pathway of l-arabinose metabolism. the purified enzyme preferred nadp+ to nad+ as a coenzyme. kinetic analysis revealed that the enzyme had high catalytic efficiency for both l-arabinose ... | 2006 | 16326697 |
| cultivation factors and population size control the uptake of nitrogen by the microalgae chlorella vulgaris when interacting with the microalgae growth-promoting bacterium azospirillum brasilense. | growth of and the capacity to take up nitrogen in the freshwater microalgae chlorella vulgaris were studied while varying the concentrations of ammonium and nitrate, the ph and the source of carbon in a synthetic wastewater growth medium when co-immobilized in alginate beads with the microalgae growth-promoting bacterium azospirillum brasilense. analyses of 29 independent experiments showed that co-immobilization of the microalgae with a. brasilense could result in two independent phenomena dire ... | 2005 | 16332319 |
| wheat root colonization and nitrogenase activity by azospirillum isolates from crop plants in korea. | nitrogen-fixing bacteria were isolated from the rhizosphere of different crops of korea. a total of 16 isolates were selected and characterized. thirteen of the isolates produced characteristics similar to those of the reference strains of azospirillum, and the remaining 3 isolates were found to be enterobacter spp. the isolates could be categorized into 3 groups based on their ardra patterns, and the first 2 groups comprised azospirillum brasilense and azospirillum lipoferum. the acetylene redu ... | 2005 | 16333334 |
| plant growth substances produced by azospirillum brasilense and their effect on the growth of pearl millet (pennisetum americanum l.). | azospirillum brasilense, a nitrogen-fixing bacterium found in the rhizosphere of various grass species, was investigated to establish the effect on plant growth of growth substances produced by the bacteria. thin-layer chromatography, high-pressure liquid chromatography, and bioassay were used to separate and identify plant growth substances produced by the bacteria in liquid culture. indole acetic acid and indole lactic acid were produced by a. brasilense from tryptophan. indole acetic acid pro ... | 1979 | 16345372 |
| characterization of azospirillum isolated from nitrogen-fixing roots of harvested sorghum plants. | root segments of harvested sorghum plants had acetylene reduction activity ranging from 11 to 61 nmol of ethylene formed per h per g (dry weight). five strains of azospirillum brasilense sp. nov. were isolated from root segments. | 1979 | 16345484 |
| association of azospirillum with grass roots. | the association between grass roots and azospirillum brasilense sp 7 was investigated by the fahraeus slide technique, using nitrogen-free medium. young inoculated roots of pearl millet and guinea grass produced more mucilaginous sheath (mucigel), root hairs, and lateral roots than did uninoculated sterile controls. the bacteria were found within the mucigel that accumulated on the root cap and along the root axes. adherent bacteria were associated with granular material on root hairs and fibril ... | 1980 | 16345490 |
| biology of azospirillum-sugarcane association: enhancement of nitrogenase activity. | azospirillum brasilense was reisolated from associations with callus tissue cultures of sugarcane and compared with stock cultures of the inoculated bacterium and related strains. although the reisolate had a growth rate similar to stock cultures, it exhibited a severalfold increase in maximum specific activity of nitrogenase. the reisolate and the parent culture had similar ultrastructure. the general ultrastructure of azospirillum is described. the bacterium was capsulated when grown on nitrog ... | 1980 | 16345531 |
| root-associated n(2) fixation (acetylene reduction) by enterobacteriaceae and azospirillum strains in cold-climate spodosols. | n(2) fixation by bacteria in associative symbiosis with washed roots of 13 poaceae and 8 other noncultivated plant species in finland was demonstrated by the acetylene reduction method. the roots most active in c(2)h(2) reduction were those of agrostis stolonifera, calamagrostis lanceolata, elytrigia repens, and phalaris arundinacea, which produced 538 to 1,510 nmol of c(2)h(4).g (dry weight). h when incubated at po(2) 0.04 with sucrose (ph 6.5), and 70 to 269 nmol of c(2)h(4). g (dry weight).h ... | 1981 | 16345687 |
| plant yield and nitrogen content of a digitgrass in response to azospirillum inoculation. | two australian soils, a vertisol (ph 6.8, 0.299% n) and a sandy yellow podzol (ph 6.2, 0.042% n), were used with digitgrass, digitaria sp. x46-2 (pi 421785), in a growth room experiment. comparisons were made between plants inoculated with live and autoclaved bacterial suspensions of australian and brazilian isolates of azospirillum brasilense. seedlings were inoculated on days 10 and 35. acetylene-reducing activity was measured five times during the experiment. dry matter yields of the digitgra ... | 1981 | 16345707 |
| improved medium for isolation of azospirillum spp. | colonies of azospirillum spp. could be readily distinguished from colonies of other diazotrophs by scarlet coloration in culture media in which congo red was included. | 1982 | 16346123 |
| nitrogenase activity (acetylene reduction) of root-associated, cold-climate azospirillum, enterobacter, klebsiella, and pseudomonas species during growth on various carbon sources and at various partial pressures of oxygen. | a comprehensive view of the diazotrophic bacterial flora of plants requires that attention be paid to the appropriate carbon and oxygen requirements during isolation of the bacteria. twenty compounds (monosaccharides, disaccharides, polyols, and organic acids) were therefore examined as carbon and energy sources for nitrogenase activity in semisolid stab cultures at po(2) values of 0.21, 0.02, and </=0.002 with 12 strains of diazotrophic root-associated bacteria. with the facultatively anaerobic ... | 1983 | 16346205 |
| enhanced mineral uptake by zea mays and sorghum bicolor roots inoculated with azospirillum brasilense. | inoculation of corn (zea mays) seeds with azospirillum brasilense strain cd or sp 7 significantly enhanced (30 to 50% over controls) the uptake of no(3), k, and h(2)po(4) into 3- to 4-day- and 2-week-old root segments. no gross changes in root morphology were observed; altered cell arrangement in the outer four or five layers of the cortex was seen in photomicrographs of cross sections of inoculated corn roots. the surface activity involved in ion uptake probably increased, as shown by the darke ... | 1983 | 16346311 |
| n(2) fixation by azospirillum brasilense and its incorporation into host setaria italica. | growth and nitrogen fixation were followed during the life cycle of setaria italica (foxtail millet) inoculated with azospirillum brasilense in controlled-environment growth chambers. the plants were fertilized at seeding with a limiting amount of combined nitrogen and maintained with an n-free mineral solution. during maturation of the plants, substantial nitrogenase activity, measured by acetylene reduction, developed in the rhizosphere, with total fixation estimated to be equivalent to 20% of ... | 1983 | 16346386 |
| [oil-oxidizing potential of associative rhizobacteria of the genus azospirillum]. | the oil-oxidizing potential of associative rhizobacteria of the genus azospirillum was studied under laboratory conditions. after screening, a. brasilense strain sr80 was chosen for further investigation. the strain was capable of degrading 56.5% of crude oil (added in a concentration of 1%) over 14 days in a medium containing malate as an additional source of carbon and energy. studies of associative properties showed that the strain had positive chemotaxis to wheat root exudates, colonized whe ... | 2005 | 15938402 |
| rhizosphere bacterial signalling: a love parade beneath our feet. | plant roots support the growth and activities of a wide variety of microorganisms that may have a profound effect on the growth and/or health of plants. among these microorganisms, a high diversity of bacteria have been identified and categorized as deleterious, beneficial, or neutral with respect to the plant. the beneficial bacteria, termed plant growth-promoting rhizobacteria (pgpr), are widely studied by microbiologists and agronomists because of their potential in plant production. azospiri ... | 2004 | 15646398 |
| microbial degradation of the organophosphate pesticide, ethion. | the organophosphate pesticide, ethion, remains a major environmental contaminant in rural australia and poses a significant threat to environmental and public health. the aerobic degradation of ethion by mesophilic bacteria isolated from contaminated soils surrounding disused cattle dip sites was investigated. two isolates, identified as pseudomonas and azospirillum species, were capable of biodegrading ethion when cultivated in minimal salts medium. the abiotic hydrolytic degradation products o ... | 2004 | 15500978 |
| structure of the o-polysaccharide of the lipopolysaccharide of azospirillum irakense kbc1. | the o-polysaccharide was isolated from the lipopolysaccharide of the plant-growth-promoting bacterium azospirillum irakense kbc1 and studied by sugar and methylation analyses, smith degradation and 1h and 13c nmr spectroscopy, including 1h, 13c hsqc and noesy experiments for linkage and sequence analysis. the following structure of the branched hexasaccharide repeating unit of the o-polysaccharide with an unusually long side chain was established: [carbohydrate structure: see text]. | 2004 | 15220092 |
| application of the indirect immunoperoxidase stain technique to the flagella of azospirillum brasilense. | an indirect immunoperoxidase stain was used to demonstrate by electron microscopy that an antigenic difference exists between the polar flagellum and the lateral flagella of azospirillum brasilense atcc 29145. | 1984 | 16346482 |
| responses of sorghum and pennisetum species to the n(2)-fixing bacterium azospirillum brasilense. | three field inoculation experiments, two in florida and one in new mexico, were conducted with azospirillum brasilense cd. each of the florida experiments evaluated two crop species. one species in each of the florida experiments responded to inoculation with a significant dry matter yield increases of 11 to 24% and nitrogen yield increases of 9 to 39%. no inoculation response was noted in the new mexico experiment. the responding species were sorghum bicolor (l.) moench (sorghum) and the inters ... | 1984 | 16346571 |
| isolation and characterization of dinitrogen-fixing bacteria from the rhizosphere of temperate cereals and forage grasses. | n(2)(c(2)h(2))-fixing bacteria were isolated from the rhizosphere of various cereals and forage grasses grown in the greenhouse and from the rhizosphere of field-grown wheat in sweden. all 46 isolates from the greenhouse plants lost their nitrogenase activity during purification. by imposing a stronger selection pressure, we obtained pure isolates with nitrogenase activity from field-grown wheat. some isolates were identified as enterobacter agglomerans and bacillus polymyxa, but several bacteri ... | 1984 | 16346635 |