Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| [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 |
| [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 |
| 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 |
| 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 |
| 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 |
| 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 |
| [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 |
| 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 |
| l-arabinose 1-dehydrogenase: a novel enzyme involving in bacterial 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 conversion of l-arabinose to l-arabino-gamma-lactone as an enzyme involved in the first step of this l-arabinose metabolic pathway. the purified enzyme was preferred nadp+ to nad+ as a coenzyme. kinetic analysis revealed that the enzyme had a high catalytic efficiency for both l-arabinose and d-galactose and ... | 2005 | 17150757 |
| mode of utilization of amino acids as growth substrates by azospirillum brasilense. | the study was undertaken to analyze the rate of uptake and utilization of various amino acids by azospirillum brasilense sp81 (rg) in a basal mineral salts solution under non-nitrogen fixing condition. these amino acids including other nitrogenous compounds were tested for both n- and c-sources. the kinetic constants (km and vmax) of uptake of some amino acids (e.g. lysine, arginine, proline, glutamine and glutamic acid) were exploited using a hanes-woolf plot, and discussed in the context of ni ... | 2005 | 16359132 |
| adp-ribosylation of dinitrogenase reductase in azospirillum brasilense is regulated by amtb-dependent membrane sequestration of drag. | nitrogen fixation in some diazotrophic bacteria is regulated by mono-adp-ribosylation of dinitrogenase reductase (nifh) that occurs in response to addition of ammonium to the extracellular medium. this process is mediated by dinitrogenase reductase adp-ribosyltransferase (drat) and reversed by dinitrogenase reductase glycohydrolase (drag), but the means by which the activities of these enzymes are regulated are unknown. we have investigated the role of the p(ii) proteins (glnb and glnz), the amm ... | 2006 | 16359338 |
| tgge analysis of the diversity of ammonia-oxidizing and denitrifying bacteria in submerged filter biofilms for the treatment of urban wastewater. | the spatial and temporal diversity of the bacterial community-forming biofilms in a pilot-scale submerged biofilter used for the treatment of urban wastewater was analyzed by a temperature-gradient gel electrophoresis (tgge) approach. tgge profiles based on partial sequence of the 16s rrna gene showed that the community composition of the biofilms remained fairly stable along the column system and during the whole time of operation of the biofilter (more than 1 year). community-profiling based o ... | 2006 | 16391923 |
| growth dynamics of azospirillum lipoferum at steady and transitory states in the presence of nh. | the objective of this paper was to study the adaptation dynamics and biochemical response of azospirillum lipoferum grown in a continuous culture at various environmental shifts. | 2006 | 16430505 |
| characterization of two trpe genes encoding anthranilate synthase alpha-subunit in azospirillum brasilense. | the previous report from our laboratory has recently identified a new trpe gene (termed trpe2) which exists independently in azospirillum brasilense yu62. in this study, amplification of trpe(g) (termed trpe1(g) here) confirmed that there are two copies of trpe gene, one trpe being fused into trpg while the other trpe existed independently. this is the first report to suggest that two copies of the trpe gene exist in this bacterium. comparison of the nucleotide sequence demonstrated that putativ ... | 2006 | 16430864 |
| cloning and characterization of a fur homologue from azospirillum brasilense sp7. | a homologue of the ferric uptake regulator gene, fur, was identified from a azospirillum brasilense sp7 genomic dna clone. experiments performed with transcriptional lacz fusions demonstrated that the a. brasilense fur homologue regulated the expression of two fur regulated escherichia coli genes: fiu (ferric iron uptake) and fhuf (ferric hydroxamate uptake). a differential regulation by the cognate fur and the heterologous fur homologue in response to the iron status of the growth medium was al ... | 2006 | 16450071 |
| identification of nif genes in n2-fixing bacterial strains isolated from rice fields along the yangtze river plain. | the aim of this research was to identify nifh and nifhdkye ' genes in twenty strains of n2-fixing heterotrophic bacteria isolated from rice fields in the yangtze river plain. southern hybridization of the total dna from each strain was performed with the klebsiella pneumoniae nifhdkye ' gene probe (6.2 kb eco ri fragment from psa30) and the azospirillum brasilense nifh gene probe (0.6 kb eco ri-hin diii fragment from phu8). we found that eco ri fragments of total dna from aeromonas hydrophila hy ... | 2006 | 16463319 |
| cloning, sequencing, and characterization of the azospirillum brasilense fhue gene. | the fhue gene of escherichia coli encodes the fhue protein, which is a receptor protein in the coprogen-mediated siderophore iron-transport system. a fhue gene homologue from azospirillum brasilense, a nitrogen-fixing soil bacterium that lives in association with the roots of cereal grasses, was cloned, sequenced, and characterized. the a. brasilense fhue encodes a protein of 802 amino acids with a predicted molecular weight of approximately 87 kda. the deduced amino-acid sequence showed a high ... | 2006 | 16502288 |
| factors affecting the attachment of rhizospheric bacteria to bean and soybean roots. | the plant rhizosphere is an important soil ecological environment for plant-microorganism interactions, which include colonization by a variety of microorganisms in and around the roots that may result in symbiotic, endophytic, associative, or parasitic relationships within the plant, depending on the type of microorganisms, soil nutrient status, and soil environment. rhizosphere competence may be attributable to the differences in the extent of bacterial attachment to the root surface. we prese ... | 2006 | 16684104 |
| phylogeny of the 1-aminocyclopropane-1-carboxylic acid deaminase-encoding gene acds in phytobeneficial and pathogenic proteobacteria and relation with strain biogeography. | deamination of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (acc) is a key plant-beneficial trait found in plant growth-promoting rhizobacteria (pgpr) and phytosymbiotic bacteria, but the diversity of the corresponding gene (acds) is poorly documented. here, acds sequences were obtained by screening putative acc deaminase sequences listed in databases, based on phylogenetic properties and key residues. in addition, acds was sought in 71 proteobacterial strains by pcr amplificatio ... | 2006 | 16689877 |
| azospirillum melinis sp. nov., a group of diazotrophs isolated from tropical molasses grass. | fifteen bacterial strains isolated from molasses grass (melinis minutiflora beauv.) were identified as nitrogen-fixers by using the acetylene-reduction assay and pcr amplification of nifh gene fragments. these strains were classified as a unique group by insertion sequence-pcr fingerprinting, sds-page protein patterns, dna-dna hybridization, 16s rrna gene sequencing and morphological characterization. phylogenetic analysis of the 16s rrna gene indicated that these diazotrophic strains belonged t ... | 2006 | 16738102 |
| relationship between in vitro enhanced nitrogenase activity of an azospirillum brasilense sp7 mutant and its growth-promoting activities in situ. | in this work, we further analyzed an azospirillum brasilense sp7 mutant (sp7::tn5-33) showing a pleiotrophic phenotype due to a tn5 insertion into an open reading frame of 840 bp (orf280). the deduced amino acid sequence of this region has high similarity to a family of universal stress proteins. because the most interesting property exhibited by the sp7::tn5-33 mutant was an enhanced in vitro nitrogen fixation activity, we addressed the question of whether it could benefit the host plant. we fo ... | 2006 | 16775786 |
| role of cheb and cher in the complex chemotactic and aerotactic pathway of azospirillum brasilense. | it has previously been reported that the alpha-proteobacterium azospirillum brasilense undergoes methylation-independent chemotaxis; however, a recent study revealed cheb and cher genes in this organism. we have constructed cheb, cher, and chebr mutants of a. brasilense and determined that the cheb and cher proteins under study significantly influence chemotaxis and aerotaxis but are not essential for these behaviors to occur. first, we found that although cells lacking cheb, cher, or both were ... | 2006 | 16788185 |
| a novel alpha-ketoglutaric semialdehyde dehydrogenase: evolutionary insight into an alternative pathway of bacterial l-arabinose metabolism. | azospirillum brasilense possesses an alternative pathway of l-arabinose metabolism, which is different from the known bacterial and fungal pathways. in a previous paper (watanabe, s., kodaki, t., and makino, k. (2006) j. biol. chem. 281, 2612-2623), we identified and characterized l-arabinose 1-dehydrogenase, which catalyzes the first reaction step in this pathway, and we cloned the corresponding gene. here we focused on the fifth enzyme, alpha-ketoglutaric semialdehyde (alphakgsa) dehydrogenase ... | 2006 | 16835232 |
| auxin signaling in plant defense. | 2006 | 16840680 | |
| phase variation and genomic architecture changes in azospirillum. | the plant growth-promoting rhizobacterium azospirillum lipoferum 4b generates in vitro at high frequency a stable nonswimming phase variant designated 4v(i), which is distinguishable from the wild type by the differential absorption of dyes. the frequency of variants generated by a reca mutant of a. lipoferum 4b was increased up to 10-fold. the pleiotropic modifications characteristic of the phase variant are well documented, but the molecular processes involved are unknown. here, the objective ... | 2006 | 16855225 |
| resolving stoichiometries and oligomeric states of glutamate synthase protein complexes with curve fitting and simulation of electrospray mass spectra. | a complicating factor in analyzing electrospray ionization mass spectra of intact macromolecular heterogeneous protein complexes is the potential overlap of ions from different species present in solution. therefore, it is often not possible to assign all ion signals. with the aim of allowing the more efficient and comprehensive analysis of very complex mass spectra of intact heterogeneous protein complexes we developed a software program: somms. the program uses simple user input parameters tog ... | 2006 | 16862623 |
| pleiotropic physiological effects in the plant growth-promoting bacterium azospirillum brasilense following chromosomal labeling in the clpx gene. | azospirillum brasilense 8-i was chromosomally labeled with green fluorescent protein (gfp) genes, using either the native promoterless gfp gene or the mutant gfpmut2 gene under the transcriptional control of the neomycin phosphate transferase (npt2) promoter inserted into tn5 suicide plasmid vectors. one a. brasilense exconjugant, showing a steady and strong fluorescence following irradiation with 365-nm uv light was characterized in detail. this strain, a. brasilense 8-i-gfp showed increased n( ... | 2006 | 16867140 |
| [chemical composition and immunochemical characteristics of the lipopolysaccharide of nitrogen-fixing rhizobacterium azospirillum brasilense cd]. | the chemical composition of the lipopolysaccharide of the associative diazotrophic rhizobacterium azospirillum brasilense cd has been studied. among the main components of the hydrophobic part of the lipopolysaccharide, we identified 3-hydroxytetradecanoic, hexadecenoic, 3-hydroxyhexadecanoic, hexadecanoic, octadecenoic, and nanodecanoic fatty acids; the carbohydrate part contained rhamnose, galactose, and mannose. polyclonal antibodies against the preparation under study were raised in rabbits. ... | 2006 | 16871806 |
| structure and activity of bacterial community inhabiting rice roots and the rhizosphere. | root-derived carbon provides a major source for microbial production and emission of ch4 from rice field soils. therefore, we characterized the structure and activity of the bacterial community inhabiting rice roots and the rhizosphere. in the first experiment, dna retrieved from rice roots was analysed for bacterial 16s rrna genes using cloning, sequencing and in situ hybridization. in the second experiment, rice plants were pulse-labelled with 13co2 (99% of atom 13c) for 7 days, and the bacter ... | 2006 | 16872399 |
| identification, cloning and characterization of cysk, the gene encoding o-acetylserine (thiol)-lyase from azospirillum brasilense, which is involved in tellurite resistance. | o-acetylserine (thiol)-lyase (cysteine synthase) was purified from azospirillum brasilense sp7. after hydrolysis of the purified protein, amino acid sequences of five peptides were obtained, which permitted the cloning and sequencing of the cysk gene. the deduced amino acid sequence of cysteine synthase exhibited homology with several putative proteins from alpha- and gammaproteobacteria. azospirillum brasilense sp7 cysk exhibited 58% identity (72% similarity) with escherichia coli k12 and salmo ... | 2006 | 16907731 |
| identification and characterization of l-arabonate dehydratase, l-2-keto-3-deoxyarabonate dehydratase, and l-arabinolactonase involved in an alternative pathway of l-arabinose metabolism. novel evolutionary insight into sugar metabolism. | azospirillum brasiliense possesses an alternative pathway of l-arabinose metabolism, different from the known bacterial and fungal pathways. in the preceding articles, we identified and characterized l-arabinose-1-dehydrogenase and alpha-ketoglutaric semialdehyde dehydrogenase, which catalyzes the first and final reaction steps in this pathway, respectively (watanabe, s., kodaki, t., and makino, k. (2006) j. biol. chem. 281, 2612-2623 and watanabe, s., kodaki, t., and makino, k. (2006) j. biol. ... | 2006 | 16950779 |
| interactions between pii proteins and the nitrogenase regulatory enzymes drat and drag in azospirillum brasilense. | in azospirillum brasilense adp-ribosylation of dinitrogenase reductase (nifh) occurs in response to addition of ammonium to the extracellular medium and is mediated by dinitrogenase reductase adp-ribosyltransferase (drat) and reversed by dinitrogenase reductase glycohydrolase (drag). the p(ii) proteins glnb and glnz have been implicated in regulation of drat and drag by an as yet unknown mechanism. using pull-down experiments with his-tagged versions of drat and drag we have now shown that drat ... | 2006 | 16963029 |
| adenosine diphosphate ribosylation of dinitrogenase reductase and adenylylation of glutamine synthetase control ammonia excretion in ethylenediamine-resistant mutants of azospirillum brasilense sp7. | azospirillum brasilense is a nitrogen-fixing, root-colonizing bacterium that brings about plant-growth-promoting effects mainly because of its ability to produce phytohormones. ethylenediamine (eda)-resistant mutants of a. brasilense were isolated and screened for their higher ability to decrease acetylene and release ammonia in the medium. one of the mutants showed considerably higher levels of acetylene decrease and ammonia excretion. nitrogenase activity of this mutant was relatively resistan ... | 2006 | 16972125 |
| bacterial lateral flagella: an inducible flagella system. | flagella are complex surface organelles that allow bacteria to move towards favourable environments and that contribute to the virulence of pathogenic bacteria through adhesion and biofilm formation on host surfaces. there are a few bacteria that possess functional dual flagella systems, such as vibrio parahaemolyticus, some mesophilic aeromonas spp., rhodospirillum centenum and azospirillum brasilense. these bacteria are able to express both a constitutive polar flagellum required for swimming ... | 2006 | 16978346 |
| [wheat lectin as a factor in plant-microbial communication and a stress response protein]. | wheat lectin (wheat germ agglutinin, wga), a representative of a broad group of cereal lectins, is excreted by plant roots into the surrounding medium and interacts with both pathogenic microflora and growth-stimulating rhizobacteria. wga was found to serve as a molecular signal for the rhizobacterium azospirillum brasilense, which forms endophytic and associative symbioses with wheat plants. the bacterial response to the lectin was pleiotropic: wga at concentrations from 10(-10) to 10(-6) m exe ... | 2006 | 17025182 |
| reclassification of roseomonas fauriae rihs et al. 1998 as a later heterotypic synonym of azospirillum brasilense tarrand et al. 1979. | the relatedness of roseomonas fauriae and azospirillum brasilense was investigated using phenotypic methods and dna-dna hybridization. conventional biochemical tests did not differentiate between the two taxa. dna-dna hybridization experiments revealed high values for relatedness between the type strains of these species and suggest that these two taxa constitute a single species. strains previously identified as r. fauriae should be reclassified as a. brasilense, with the name roseomonas fauria ... | 2006 | 17158972 |
| [16s rdna-rflp analysis of structure and diversity of an aerobic microbial community degrading hexachlorobenzene]. | hexachlorobenzene is a chlorinated aromatic hydrocarbon that was widely used as a seed dressing for prevention of fungal growth on crops, and is also a component of fireworks, ammunition, and synthetic rubbers. because of the bioaccumulation and persistence of hexachlorobenzene as well as its potential toxicity, hexachlorobenzene must be removed from environment. the potential for aerobic dechlorination of hexachlorobenzene by a hexachlorobenzene-adapted mixed culture was investigated. an aerobi ... | 2006 | 17172024 |
| targeted engineering of azospirillum brasilense sm with indole acetamide pathway for indoleacetic acid over-expression. | rhizospheric bacterial strains are known to produce indole-3-acetic acid (iaa) through different pathways, and such iaa may be beneficial to plants at low concentrations. iaa biosynthesis by a natural isolate of azospirillum brasilense sm was studied and observed to be tryptophan-inducible and -dependent in nature. while our work demonstrated the operation of the indole pyruvic acid pathway, the biochemical and molecular evidence for the genes of the indole acetamide (iam) pathway were lacking i ... | 2006 | 17215899 |
| characterization of selected groups of microorganisms occurring in soil rhizosphere and phyllosphere of oats. | studies were carried out on the microflora of phyllosphere and soil rhizosphere of hulled (chwat variety) and naked (akt variety) oats. the material taken for study embraced samples of leaves and soil rhizosphere taken from cultivations differing in extent of nitrogen fertilization. the studies involved determination of total number of aerobic heterotrophic bacteria belonging to the genus pseudomonas and microscopic hyphal fungi. qualitative determinations focused on bacteria belonging to the ge ... | 2006 | 17338275 |
| 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 |
| n-acyl-homoserine lactone-mediated quorum-sensing in azospirillum: an exception rather than a rule. | forty azospirillum strains were tested for their ability to synthesize n-acyl-homoserine lactones (ahls). ahl production was detected for four strains belonging to the lipoferum species and isolated from a rice rhizosphere. ahl molecules were structurally identified for two strains: azospirillum lipoferum tvv3 produces 3o,c(8)-hsl (n-3-oxo-octanoyl-homoserine-lactone), c(8)-hsl (n-3-octanoyl-homoserine-lactone), 3o,c(10)-hsl (n-3-oxo-decanoyl-homoserine-lactone), 3oh,c(10)-hsl (n-3-hydroxy-decan ... | 2006 | 17064258 |
| root phospholipids in azospirillum-inoculated wheat seedlings exposed to water stress. | azospirillum-plant association is accompanied by biochemical changes in roots which, in turn, promote plant-growth and tolerance to water stress. to shed light on the possible factors underlying these effects, roots from azospirillum brasilense sp245-inoculated triticum aestivum seedlings growing in darkness under osmotic stress were analyzed for phospholipid (pl) composition, fatty acid (fa) distribution profiles and degree of unsaturation of the major pl classes. azospirillum inoculation dimin ... | 2006 | 17123824 |
| cdna-aflp reveals differentially expressed genes related to cell aggregation of azospirillum brasilense. | the response regulatory gene flca controls the differentiation process of azospirillum brasilense from vegetative state to cyst-like forms, both in culture and in association with plants. in contrast to the wild type parental strain sp7, strain sp72002, a tn5 induced flca(-) mutant, does not aggregate, does not differentiate from motile, vibroid cells into nonmotile, cyst-like forms and lacks some of the exopolysaccharide material on its cell surface. here we aimed to identify differentially exp ... | 2006 | 17147763 |
| [effect of congo red on the motility of the bacterium azospirillum brasilense]. | in semiliquid laboratory media, the bacterium azospirillum brasilense migrates with the formation of swarming rings. it is demonstrated that adsorption of the sulfonated azodye congo red confers on a. brasilense the ability to consistently spread in a semiliquid agar and form microcolonies. spontaneous variants of a. brasilense with rapid swarming are described, as well as variants that swarm in the presence of congo red. it is assumed that at least two types of compounds are formed, which are ( ... | 2006 | 16579446 |
| inoculation effects of pseudomonas putida, gluconacetobacter azotocaptans, and azospirillum lipoferum on corn plant growth under greenhouse conditions. | alcohol production from corn is gaining importance in ontario, canada, and elsewhere. a major cost of corn production is the cost of chemical fertilizers and these continue to increase in price. the competitiveness of alcohol with fossil fuels depends on access to low-cost corn that allows growers to earn a sustainable income. in this study we set out to determine if we can identify root-associated microorganisms from ontario-grown corn that can enhance the nutrient flow to corn roots, directly ... | 2006 | 16598630 |
| instrumental analysis of bacterial cells using vibrational and emission mössbauer spectroscopic techniques. | in biosciences and biotechnology, the expanding application of physicochemical approaches using modern instrumental techniques is an efficient strategy to obtain valuable and often unique information at the molecular level. in this work, we applied a combination of vibrational (fourier transform infrared (ftir), ft-raman) spectroscopic techniques, useful in overall structural and compositional analysis of bacterial cells of the rhizobacterium azospirillum brasilense, with 57co emission mössbauer ... | 2006 | 17723559 |
| 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 |
| characterization of phenylpyruvate decarboxylase, involved in auxin production of azospirillum brasilense. | azospirillum brasilense belongs to the plant growth-promoting rhizobacteria with direct growth promotion through the production of the phytohormone indole-3-acetic acid (iaa). a key gene in the production of iaa, annotated as indole-3-pyruvate decarboxylase (ipdc), has been isolated from a. brasilense, and its regulation was reported previously (a. vande broek, p. gysegom, o. ona, n. hendrickx, e. prinsen, j. van impe, and j. vanderleyden, mol. plant-microbe interact. 18:311-323, 2005). an ipdc- ... | 2007 | 17766418 |
| microbial degradation of the biocide polyhexamethylene biguanide: isolation and characterization of enrichment consortia and determination of degradation by measurement of stable isotope incorporation into dna. | to isolate micro-organisms capable of utilizing polyhexamethylene biguanide (phmb) as a sole source of nitrogen, and to demonstrate biodegradation of the biocide. | 2007 | 17897221 |
| development and standardization of cyst based liquid formulation of azospirillum bioinoculant. | azospirillum bioinoculant is well known for its high nitrogen fixing and plant growth promoting characters. the carrier based bioinoculants generally suffer from shorter shelf life, poor quality, high contamination and low field performance. therefore, it is necessary to develop alternative new formulation of inoculants where cyst based inoculants can play significant role. the cyst based liquid formulation was developed by inoculating azospirillum into the cyst inducing minimal salts medium (ms ... | 2007 | 17899796 |
| promoter-trap identification of wheat seed extract-induced genes in the plant-growth-promoting rhizobacterium azospirillum brasilense sp245. | azospirillum strains have been used as plant-growth-promoting rhizobacteria (pgpr) of cereal crops, but their adaptation to the root remains poorly understood. here, we used a global approach based on differential fluorescence induction (dfi) promoter trapping to identify genes of the wheat isolate azospirillum brasilense sp245 that are induced in the presence of spring wheat seed extracts. fluorescence-based flow cytometry sorting of sp245 cells was validated using placz, psbpa and pnifh promot ... | 2007 | 17906157 |
| [role of the carbohydrate-binding center of bacterial lectin in the effect on adipocytes under the influence of increased temperature]. | the effect of temperature and lectin from bacteria of the genues azospirillum with blocked activity on human adipose tissue cells has been studied. the temperature used was 43.5 +/- 0.5 degrees c. comparative results are given for the effect of lectin with the blocked and active carbohydrate-binding centers on adipocytes during heating, and the time course of the structural changes of adipocytes is described. when lectin with the active carbohydrate-binding centers was used for treatment, the he ... | 2007 | 17907410 |
| [isolation and characterization of nitrogen-fixing bacteria of the genus azospirillum from the soil of a sphagnum peat bog]. | the presence of nitrogen-fixing bacteria of the genus azospirillum in the soils of acidic raised sphagnum bogs is revealed for the first time. three azospirillum strains, b2, b21, and b22, were isolated as a component of methane-oxidizing enrichment cultures, whereas attempts to isolate them directly from peat samples have failed. the results of comparative analysis of the nucleotide sequences of 16s rrna genes, dna-dna hybridization, and the analysis of the sequences of the functional genes enc ... | 2007 | 17410881 |
| functional expression of an acyl carrier protein (acp) from azospirillum brasilense alters fatty acid profiles in escherichia coli and brassica juncea. | acyl carrier protein (acp) is a central cofactor for de novo fatty acid synthesis, acyl chain modification and chain-length termination during lipid biosynthesis in living organisms. although the structural and functional organization of the acps in bacteria and plant are highly conserved, the individual acp is engaged in the generation of sets of signature fatty acids required for specific purpose in bacterial cells and plant tissues. realizing the fact that the bacterial acp being originated e ... | 2007 | 17466529 |
| biofilm formation by plant-associated bacteria. | plants support a diverse array of bacteria, including parasites, mutualists, and commensals on and around their roots, in the vasculature, and on aerial tissues. these microbes have a profound influence on plant health and productivity. bacteria physically interact with surfaces to form complex multicellular and often multispecies assemblies, including biofilms and smaller aggregates. there is growing appreciation that the intensity, duration, and outcome of plant-microbe interactions are signif ... | 2007 | 17506679 |
| attachment of bacteria to the roots of higher plants. | attachment of soil bacteria to plant cells is supposedly the very early step required in plant-microbe interactions. attachment also is an initial step for the formation of microbial biofilms on plant roots. for the rhizobia-legume symbiosis, various mechanisms and diverse surface molecules of both partners have been proposed to mediate in this process. the first phase of attachment is a weak, reversible, and unspecific binding in which plant lectins, a ca(+2)-binding bacterial protein (rhicadhe ... | 2007 | 17521360 |
| [impact of bacterial lectin on functional activity of lymphocytes]. | impact of azospirillum brasilense sp7 lectin with carbohydrate specificity to l-fucose on t- and b-lymphocytes production, activity of il-1alpha, and tnf-alpha was studied in vitro and compared with influence of red kidney bean phytohemagglutinin (pha) on the same parameters. increase of growth of t- and b-cells subpopulations has been shown that point to stimulatory effect of the bacterial lectin. bacterial lectin of a. brasilense also increased synthesis of il-1alpha and tnf-alpha. it has been ... | 2007 | 17523482 |
| preliminary crystallographic analysis of l-2-keto-3-deoxyarabonate dehydratase, an enzyme involved in an alternative bacterial pathway of l-arabinose metabolism. | l-2-keto-3-deoxyarabonate (l-kda) dehydratase is a novel member of the dihydrodipicolinate synthase (dhdps)/n-acetylneuraminate lyase (nal) protein family and catalyzes the hydration of l-kda to alpha-ketoglutaric semialdehyde. l-kda dehydratase was overexpressed, purified and crystallized at 291 k using the hanging-drop vapour-diffusion method. the crystal diffracts to 2.0 a resolution using synchrotron radiation and belongs to the trigonal space group p3(1)21 or its enantiomorph p3(2)21, with ... | 2007 | 17565178 |
| isolation of a flagellar operon in azospirillum brasilense and functional analysis of flbd. | a 10 kb fragment containing flif, flih, flin, mota, flbd, flha, flhf and flen genes was cloned from the genomic dna of azospirillum brasilense yu62. these eight genes appear to be structurally organized as an operon. flbd, encoded by flbd, has a hth dna binding domain and shows homology to sigma(54)-dependent transcriptional activators such as ntrc, nifa and dctd. an in-frame deletion of flbd in a. brasilense abolishes biosynthesis of lateral flagella and swarming ability when grown on semi-soli ... | 2007 | 17572072 |
| alterations in seedling vigour and antioxidant enzyme activities in catharanthus roseus under seed priming with native diazotrophs. | an experiment was conducted on catharanthus roseus to study the effect of seed treatments with native diazotrophs on its seedling growth and antioxidant enzyme activities. the treatments had significant influence on various seedling parameters. there is no significant influence on dry matter production with the diazotrophs, azospirillum and azotobacter. however, the vital seedling parameters such as germination percentage and vigour index were improved. azotobacter treatment influenced maximum o ... | 2007 | 17610323 |
| [glutamine synthetase of the rhizobacterium azospirillum brasilense: specific features of catalysis and regulation]. | data on glutamine synthetase (gs) of azospirillum brasilense, a rhizobacterium stimulating plant growth, have been reviewed. gs of the azospirillum is a type alpha12 dodecamer with oligomer and monomer having molecular weights of 630 and 52 kda, respectively. glutamine synthesis is performed in 12 active sites of the enzyme, depending, first and foremost, on the extent of gs adenylation and, secondarily, on the exact bivalent metal cations involved in the catalysis. structural characteristics an ... | 2007 | 17619573 |
| [the effect of combined and separate inoculation of alfalfa plants with azospirillum lipoferum and sinorhizobium meliloti on denitrification and nitrogen-fixing activities]. | the effects of associative nitrogen fixer azospirillum lipoferum strain 137 and root nodule bacteria sinorhizobium meliloti after combined and separate inoculation of alfalfa seedlings on the background of mineral nitrogen applied at various times were studied. it was demonstrated that exudates of the alfalfa seedlings with the first pair of cotyledonary leaves already provide a high activity of these bacteria in the rhizosphere. to 74.6% of the introduced nitrate was transformed into n2o when t ... | 2007 | 17619579 |
| oxygen and redox sensing by two-component systems that regulate behavioral responses: behavioral assays and structural studies of aer using in vivo disulfide cross-linking. | a remarkable increase in the number of annotated aerotaxis (oxygen-seeking) and redox taxis sensors can be attributed to recent advances in bacterial genomics. however, in silico predictions should be supported by behavioral assays and genetic analyses that confirm an aerotaxis or redox taxis function. this chapter presents a collection of procedures that have been highly successful in characterizing aerotaxis and redox taxis in escherichia coli. the methods are described in enough detail to ena ... | 2007 | 17628141 |
| geminicoccus roseus gen. nov., sp. nov., an aerobic phototrophic alphaproteobacterium isolated from a marine aquaculture biofilter. | a gram-negative, strictly aerobic, diplococcoid bacterium (strain d2-3(t)) was isolated from the biofilter of a recirculating marine aquaculture system. phylogenetic analysis of the 16s rrna gene sequence of d2-3(t) indicated that the new organism occupied a novel lineage within the alpha-1 subclass of proteobacteria and was related to the genera rhodothalassium, azospirillum, craurococcus, acidiphilium, and tistrella. the highest sequence similarity (90.8%) of the 16s rrna gene sequence of d2-3 ... | 2007 | 17643894 |
| [detection of a surface sheath on azospirillum brasilense polar flagellum]. | the presence of a polysaccharide sheath on the surface of the polar flagellum of azospirillum brasilense was revealed by immunoelectron microscopy and immunodiffusion analysis with strain-specific antibodies to lipopolysaccharides (lps). the antigenic identity of a. brasilense sp245 sheath material and one of the two o-specific polysaccharides of its somatic lps was demonstrated. the screening effect of the sheath in respect to flagellin was determined by agglutination tests and by the inhibitio ... | 2007 | 18297874 |
| azospirillum canadense sp. nov., a nitrogen-fixing bacterium isolated from corn rhizosphere. | a free-living diazotrophic strain, ds2(t), was isolated from corn rhizosphere. polyphasic taxonomy was performed including morphological characterization, biolog analysis, and 16s rrna, cpn60 and nifh gene sequence analyses. 16s rrna gene sequence analysis indicated that strain ds2(t) was closely related to the genus azospirillum (96 % similarity). chemotaxonomic characteristics (dna g+c content 67.9 mol%; q-10 quinone system; major fatty acid 18 : 1omega7c) were also similar to those of the gen ... | 2007 | 17329796 |