Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
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| extracellular polysaccharides are involved in the attachment of azospirillum brasilense and rhizobium leguminosarum to arbuscular mycorrhizal structures. | arbuscular mycorrhizal (am) fungi, one of the most important component of the soil microbial community, establish physical interactions with naturally occurring and genetically modified bacterial biofertilizers and biopesticides, commonly referred to as plant growth-promoting rhizobacteria (pgpr). we have used a genetic approach to investigate the bacterial components possibly involved in the attachment of two pgpr (azospirillum and rhizobium) to am roots and am fungal structures. mutants affect ... | 2001 | 11411863 |
| evidence for the presence of dna-binding proteins involved in regulation of the gene expression of indole-3-pyruvic acid decarboxylase, a key enzyme in indole-3-acetic acid biosynthesis in azospirillum lipoferum fs. | we isolated the ipdc gene coding for indole-3-pyruvic acid decarboxylase (ipdc), a key enzyme in the indole-3-pyruvic acid pathway for indole-3-acetic acid biosynthesis, in the plant growth-promoting rhizobacterium azospirillum lipoferum fs. gel mobility-shift assay showed the presence of two dna-binding proteins that might be involved in regulation of the ipdc gene expression. | 2001 | 11440156 |
| [participation of azospirillium polysaccharides in interaction with wheat root surface]. | the present study was undertaken to comparatively investigate the attachment capacities of azospirillum brasilense sp245 and its lipopolysaccharide-defective omegon-km mutants km018 and km252, as well as their activities with respect to the alteration of the morphology of wheat seedling root hairs. the adsorption dynamics of the parent sp245 and mutant km252 strains of azospirilla on the seedling roots of the soft spring wheat cv. saratovskaya 29 were similar; however, the attachment capacity of ... | 2001 | 11450462 |
| potential roles for the glnb and ntryx genes in azospirillum brasilense. | three azospirillum brasilense mutants constitutive for nitrogen fixation (nif(c)) in the presence of nh4(+) and deficient in nitrate-dependent growth were used as tools to define the roles of the glnb and ntryx genes in this organism. mutant hm14 was complemented for nitrate-dependent growth and nh4(+) regulation of nitrogenase by plasmid pl46 which contains the ntryx genes of a. brasilense. mutant hm26 was restored for nh4(+) regulation and nitrate-dependent growth by plasmid pjc1, carrying the ... | 2001 | 11470362 |
| quantitative analysis of bacterial gene expression by using the gusa reporter gene system. | an azospirillum brasilense sp7 strain containing a plasmid-borne translational cytn-gusa fusion was grown in a continuous culture to quantitatively evaluate the influence of extracellular signals (such as o(2)) on expression of the cytnoqp operon. the dissolved oxygen concentration was shifted at regular time intervals before the steady state was reached. the measured beta-glucuronidase activity was used to monitor cytn gene expression. however, as the beta-glucuronidase activity in the experime ... | 2001 | 11472903 |
| azospirillum spp. metabolize [17,17-2h2]gibberellin a20 to [17,17-2h2]gibberellin a1 in vivo in dy rice mutant seedlings. | azospirillum spp. are endophytic bacteria with beneficial effects on cereals--effects partially attributed to gibberellin production by the microorganisms. azospirillum lipoferum and azospirillum brasilense inoculated to rice dy mutant reversed dwarfism in seedlings incubated with [17,17-2h2]ga20 with formation of [17,17-2h2]ga1, showing the in vivo capacity to perform the 3beta-hydroxylation. when prohexadione-ca, an inhibitor of late steps in gibberellin biosynthesis, was added to the culture ... | 2001 | 11479384 |
| expression of horizontally transferred gene clusters: activation by promoter-generating mutations. | the occurrence of promoter-generating mutations allowing the transcription of heterologous genes has been studied in a system based on the plasmid-mediated conjugal transfer of histidine biosynthetic genes from a donor bacterium (azospirillum brasilense) into a heterologous escherichia coli mutant population lacking histidine biosynthetic ability and initially unable to recognize the transcriptional signal of the introgressed gene(s). under selective stressful conditions, his+ revertants accumul ... | 2001 | 11501672 |
| partial characterization of nif genes from the bacterium azospirillum amazonense. | azospirillum amazonense revealed genomic organization patterns of the nitrogen fixation genes similar to those of the distantly related species a. brasilense. our work suggests that a. brasilense nifhdk, nifenx, fixabc operons and nifa and glnb genes may be structurally homologous to the counterpart genes of a. amazonense. this is the first analysis revealing homology between a. brasilense nif genes and the a. amazonense genome. sequence analysis of pcr amplification products revealed similariti ... | 2001 | 11514833 |
| enriching vermicompost by nitrogen fixing and phosphate solubilizing bacteria. | the effect of inoculation of vermicompost with nitrogen-fixing azotobacter chroococcum strains, azospirillum lipoferum and the phosphate solubilizing pseudomonas striata on n and p contents of the vermicompost was assessed. inoculation of n2 fixing bacteria into vermicompost increased contents of n and p. enriching vermicompost with rock phosphate improved significantly the available p when inoculated with p. striata. during the incubation period, the inoculated bacterial strains proliferated ra ... | 2001 | 11131802 |
| ihfa gene of the bacterium myxococcus xanthus and its role in activation of carotenoid genes by blue light. | myxococcus xanthus responds to blue light by producing carotenoids. several regulatory genes are known that participate in the light action mechanism, which leads to the transcriptional activation of the carotenoid genes. we had already reported the isolation of a carotenoid-less, tn5-induced strain (mr508), whose mutant site was unlinked to the indicated regulatory genes. here, we show that omegamr508::tn5 affects all known light-inducible promoters in different ways. it blocks the activation o ... | 2001 | 11133949 |
| [search for conjugative plasmids in azospirillum brasilense and azospirillum lipoferum associated with plants]. | the conjugative plasmids in azospirillum brasilense strains s17. sp107, sp245, spbr14, jm6b2, jm82al, uq1794, uqi796 and in azospirillum lipoferum strain rg20 were prove to exist for the first time in connection with their potency to mobilize a non-conjugative incq-plasmid pvz361 from incq-group (ori rsf1010, kmr, sur. 11.4 kb) for conjugated transfer to aplasmid strains agrobacterium tumefaciens and pseudomonas putida at high frequencies. | 2002 | 12243065 |
| [use of colloid gold conjugates for identification of actins of various origin]. | some optimized methods of purifying actin from animal, plant, and bacterial cells were developed. variants of the preparation of antiactin antibodies are described which use both traditional methods of immunization and phase display technology and antigen adsorption on colloidal gold particles. the conjugates of colloidal gold with phalloidin and heavy meromyosin as well as with antibodies were proposed. it was shown that these markers make it possible to reliably identify actins of different or ... | 2002 | 12298199 |
| characterization of pigmented methylotrophic bacteria which nodulate lotononis bainesii. | root nodule isolates from a shrubby legume, lotononis bainesii, were characterized by 16s rrna gene sequencing and morphologically by substrate utilization patterns. the symbiotic genome of these isolates was analysed by partial sequencing of the nifh gene. based on the results of numerical taxonomy, the isolates formed a closely related cluster, showing no correspondence to any of the known rhizobial clusters. analysis of nearly full-length 16s rdna sequences demonstrated that these isolates we ... | 2002 | 12421082 |
| increased acidification in the rhizosphere of cactus seedlings induced by azospirillum brasilense. | acidification of the rhizosphere of cactus seedlings (giant cardon, pachycereus pringlei) after inoculation with the plant growth-promoting bacterium azospirillum brasilense cd, in the presence or absence of ammonium and nitrate, was studied to understand how to increase growth of cardon seedlings in poor desert soils. while ammonium enhanced rhizosphere and liquid culture acidification, inoculation with the bacteria enhanced it further. on the other hand, nitrate increased ph of the rhizosphere ... | 2002 | 12435098 |
| oleomonas sagaranensis gen. nov., sp. nov., represents a novel genus in the alpha-proteobacteria. | a gram-negative bacterium was previously isolated from an oil field in shizuoka, japan, and designated strain hd-1. here we have performed detailed characterization of the strain, and have found that it represents a novel genus. the 16s rrna sequence of strain hd-1 displayed highest similarity to various uncultured species (86.7-99.7%), along with 86.2-88.2% similarity to sequences from azospirillum, methylobacterium, rhizobium, and hyphomicrobium, all members of the alpha-proteobacteria. phylog ... | 2002 | 12480113 |
| crystallization and preliminary x-ray diffraction analysis of a novel pectate lyase from azospirillum irakense. | the pela gene from the n(2)-fixing plant-associated bacterium azospirillum irakense encodes a pectate lyase. analysis of the corresponding amino-acid sequence revealed no homology to other bacterial, plant and fungal pectinases of known published structure, resulting in the classification of the enzyme in a new pectate lyase family. the a. irakense pela has been crystallized using the hanging-drop vapour-diffusion method at 277 k. the crystals are hexagonal, with unit-cell parameters a = b = 85. ... | 2002 | 11807254 |
| cloning and characterisation of the azospirillum brasilense glnd gene and analysis of a glnd mutant. | nitrogen regulation in bacteria involves the capacity to sense the availability of fixed nitrogen and to translate a signal indicating nitrogen deficiency or nitrogen excess into a cellular response. one of the key enzymes in this complex regulation process, the uridylyltransferase/uridylyl-removing (utase) enzyme, encoded by the glnd gene, was characterised in the diazotroph azospirillum brasilense, which promotes plant growth. the glnd gene product is responsible for the uridylylation of both ... | 2002 | 11810255 |
| involvement of glnb, glnz, and glnd genes in the regulation of poly-3-hydroxybutyrate biosynthesis by ammonia in azospirillum brasilense sp7. | the role of three key nitrogen regulatory genes, glnb (encoding the p(ii) protein), glnz (encoding the p(z) protein), and glnd (encoding the glnd protein), in regulation of poly-3-hydroxybutyrate (phb) biosynthesis by ammonia in azospirillum brasilense sp7 was investigated. it was observed that glnb glnz and glnd mutants produce substantially higher amounts of phb than the wild type produces during the active growth phase. glnb and glnz mutants have phb production phenotypes similar to that of t ... | 2002 | 11823250 |
| [characteristics of genes identified in the 120 mda plasmid dna in a mutant of azospirillum brasilense sp245 bacteria, defective in polar flagellation and swarming]. | the sequencing data were analyzed for two regions of the 120-mda plasmid (p120) of azospirillum brasilense sp245. the 2420-bp region i, which flanks the omegon insertion in the sk048 mutant defective in production of the polar flagellum (fla-) and swarming (swa-), was shown to contain a cluster of two open reading frames (orf) that possess properties of coding sequences (cdss). the ntra (sigma 54) boxes were found in their upstream regions. the products of orf1 and orf2 are 16.5 and 15.5 kda in ... | 2002 | 11852790 |
| [the use of fragments of the 85- and 120-mda plasmids of azospirillum brasilense sp245 to study the plasmid rearrangement in this bacterium and to search for homologous sequences in plasmids of azospirillum brasilense sp7]. | a spontaneous loss of the 85- (p85) and 120-mda (p120) replicons and simultaneous generation of a plasmid of more than 300 mda were associated with defects in synthesis of o-specific and calcofluor-binding polysaccharides and had no effect on flagellation and motility of the azospirillum brasilense sp245.5 mutant. the plasmid rearrangement was studied by hybridization of dnas from the wild-type sp245 strain and the sp245.5 mutant with p85 and p120 fragments that contained loci involved in format ... | 2002 | 11898609 |
| towards growth of arbuscular mycorrhizal fungi independent of a plant host. | when surface-sterilized spores of the arbuscular mycorrhizal fungus (amf) glomus intraradices sy167 were germinated on agar plates in the slightly modified minimum mineral medium described by g. bécard and j. a. fortin (new phytol. 108:211-218, 1988), slime-forming bacteria, identified as paenibacillus validus, frequently grew up. these bacteria were able to support growth of the fungus on the agar plates. in the presence of p. validus, hyphae branched profusely and formed coiled structures. the ... | 2002 | 11916713 |
| inhibition of biosynthesis and activity of nitrogenase in azospirillum brasilense sp7 under salinity stress. | azospirillum brasilense is a microaerophilic, plant growth-promoting bacterium, whose nitrogenase activity has been shown to be sensitive to salinity stress. growth of a. brasilense in semi-solid medium showed that diazotrophic growth in n-free medium was relatively less sensitive to high nacl concentrations (200-400 mm) than that in presence of nh4+. increase in salinity stress to diazotrophic a. brasilense in the semi-solid medium led to the migration of the pellicle to deeper anaerobic zones. ... | 2002 | 11927988 |
| a major chemotaxis gene cluster in azospirillum brasilense and relationships between chemotaxis operons in alpha-proteobacteria. | azospirillum brasilense shows chemotaxis to a variety of nutrients and oxygen. genes encoding the central signal transduction pathway in chemotaxis were identified by phenotypic complementation of generally non-chemotactic mutants. sequencing of a dna fragment, which complemented two different mutants, revealed a region of five open reading frames translated in one direction and encoding homologs of known genes comprising excitation and adaptation pathways for chemotaxis in other bacterial speci ... | 2002 | 11934495 |
| modeling growth and biochemical activities of azospirillum spp. | an unstructured mathematical model was developed and used in the evaluation of biochemical activities of four azospirillum spp. strains grown in batch cultures in a high c/n-ratio medium. the strains were evaluated for their ability to grow on fructose and produce exo-polysaccharide, and to sustain nitrogenase activity by using fructose or polysaccharides. quantitative expression of the regulation of polysaccharide synthesis and nitrogenase (acetylene reduction) activity from the mineral nitroge ... | 2002 | 11935187 |
| trace cobalt speciation in bacteria and at enzymic active sites using emission mössbauer spectroscopy. | 57co emission mössbauer spectroscopy (ems) allows the chemical state of cobalt, as influenced by its coordination environment, to be monitored in biological samples at its physiological (trace) concentrations. to draw attention to ems as a valuable tool for speciation of cobalt in biocomplexes, the process of cobalt(ii) metabolism in cells of the plant growth-promoting rhizobacterium azospirillum brasilense sp245 was investigated using ems of 57coii-doped bacterial cells. ems measurements also s ... | 2002 | 11939529 |
| [effect of azospirillum brasilense lectin on the kinetics of lymph nodes cell populations and cytokine status in experimental animals]. | the complex study of the influence of a. brasilense sp 7 lectin with carbohydrate specificity to l-fucose and d-galactose on the dynamics of cell populations in different structural functional zones of the white mice mesentery, as well as on the capacity of immunocompetent cells of mesenterial lymph nodes for synthesizing cytokines (interleukin-1, interleukin-6 and tumor necrosis factor), was carried out. a single oral administration of bacterial lectin in a dose of 4.5 micrograms produced a pro ... | 2002 | 11949252 |
| structure of the o-specific polysaccharide of the lipopolysaccharide of azospirillum brasilense sp245. | an o-specific polysaccharide was isolated from the lipopolysaccharide of a plant-growth-promoting bacterium azospirillum brasilense sp245 and studied by sugar analyses along with one- and two-dimensional 1h and 13c nmr spectroscopy, including noesy. the polysaccharide was found to be a new rhamnan with a pentasaccharide repeating unit having the following structure:-->2)-beta-d-rhap-(1-->3)-alpha-d-rhap-(1-->3)-alpha-d-rhap-(1-->2)-alpha-d-rhap-(1-->2)-alpha-d-rhap-(1--> | 2002 | 11996841 |
| laccase activity in melanin-producing strains of sinorhizobium meliloti. | laccase-like activity was detected in melanin-producing strains of sinorhizobium meliloti mainly in cells at the stationary growth phase when copper was added to the medium. the laccase showed both syringaldazine and abts (2,2'-azino-bis-ethylbenzthiazoline-6-sulfonic acid) oxidase activities and was activated by the addition of 1.7 mm sodium dodecyl sulfate. activity was totally inhibited by the addition of 1.0 mm edta, suggesting that the enzyme is a metal-dependent one. the enzyme was found t ... | 2002 | 12007664 |
| [antigenic identity of the capsule lipopolysaccharides, exopolysaccharides, and o-specific polysaccharides in azospirillum brasilense]. | the antigenic identity (and close values of electrophoretic mobility) of capsular polysaccharides, exopolysaccharides, and o-specific polysaccharides was revealed in the azospirillum brasilense strains sp7 and sp245 by the immunodiffusion and immunoelectrophoretic methods. together with the literature data on the identity of the monosaccharides composition of these polymers, this gives evidence of the absence of a specific capsular antigen in the bacteria studied. thus, extracellular azospirillu ... | 2002 | 12024821 |
| protection of tomato seedlings against infection by pseudomonas syringae pv. tomato by using the plant growth-promoting bacterium azospirillum brasilense. | pseudomonas syringae pv. tomato, the causal agent of bacterial speck of tomato, and the plant growth-promoting bacterium azospirillum brasilense were inoculated onto tomato plants, either alone, as a mixed culture, or consecutively. the population dynamics in the rhizosphere and foliage, the development of bacterial speck disease, and their effects on plant growth were monitored. when inoculated onto separate plants, the a. brasilense population in the rhizosphere of tomato plants was 2 orders o ... | 2002 | 12039714 |
| identification and isolation of genes involved in poly(beta-hydroxybutyrate) biosynthesis in azospirillum brasilense and characterization of a phbc mutant. | like many other prokaryotes, rhizobacteria of the genus azospirillum produce high levels of poly(beta-hydroxybutyrate) (phb) under suboptimal growth conditions. utilization of phb by bacteria under stress has been proposed as a mechanism that favors their compatible establishment in competitive environments, thus showing great potential for the improvement of bacterial inoculants for plants and soils. the three genes that are considered to be essential in the phb biosynthetic pathway, phba (beta ... | 2002 | 12039753 |
| identification and characterization of the two-component ntry/ntrx regulatory system in azospirillum brasilense. | two azospirillum brasilense open reading frames (orfs) exhibited homology with the two-component ntry/ntrx regulatory system from azorhizobium caulinodans. these a. brasilense orfs, located downstream to the nifr3ntrbc operon, were isolated, sequenced and characterized. the present study suggests that orf1 and orf2 correspond to the a. brasilense ntry and ntrx genes, respectively. the amino acid sequences of a. brasilense ntry and ntrx proteins showed high similarity to sensor/kinase and regulat ... | 2002 | 12045829 |
| oviposition attractancy of bacterial culture filtrates: response of culex quinquefasciatus. | oviposition attractants could be used for monitoring as well as controlling mosquitoes by attracting them to lay eggs at chosen sites. in the present study, culture filtrates of seven bacterial species were tested for their attractancy against gravid females of culex quinquefasciatus. when their oviposition active indices (oai) were studied, the culture filtrates of bacillus cereus and pseudomonas fluorescens exhibited oviposition attractancy (oai = > 0.3) at 100 ppm and the oai were respectivel ... | 2002 | 12048566 |
| [changes in the antigenic properties of azospirillum brasilense lipopolysaccharide on addition of tris(hydroxymethyl)-aminomethane into the culture medium]. | addition of tris(hydroxymethyl)-aminomethane (tris) into the culture medium of azospirillum brasilense sp245 changes the antigenic properties of the lipopolysaccharide (lps) isolated from the external membrane of the bacteria. lps preparations from the bacteria grown in the presence of tris have been analyzed by immunodiffusion, using monospecific antibodies. the disappearance of the precipitation band corresponding to one of the two o-specific polysaccharides of the lps (o-ps1) and changes in t ... | 2002 | 12068582 |
| properties of the recombinant ferredoxin-dependent glutamate synthase of synechocystis pcc6803. comparison with the azospirillum brasilense nadph-dependent enzyme and its isolated alpha subunit. | the properties of the recombinant ferredoxin-dependent glutamate synthase of synechocystis pcc6803 were determined by means of kinetic and spectroscopic approaches in comparison to those exhibited by the bacterial nadph-dependent enzyme form. the ferredoxin-dependent enzyme was found to be similar to the bacterial glutamate synthase alpha subunit with respect to cofactor content (one fmn cofactor and one [3fe-4s] cluster per enzyme subunit), overall absorbance properties, and reactivity of the f ... | 2002 | 12069605 |
| monitoring azospirillum-wheat interactions using the gfp and gusa genes constitutively expressed from a new broad-host range vector. | to monitor the colonization of wheat roots by azospirillum brasilense, we constructed several plasmids based on the pbbr1 replicon expressing the gfp and gusa genes constitutively. both genes were placed under control of the gentamycin resistance gene promoter resulting in high levels of expression in escherichia coli and a. brasilense. the constructed plasmids were stably maintained in a. brasilense strains even in the absence of selective pressure. the colonization of wheat plants grown under ... | 2002 | 12084480 |
| expression of the nh(+)(4)-transporter gene leamt1;2 is induced in tomato roots upon association with n(2)-fixing bacteria. | plants growing in close association with n(2)-fixing bacteria are able to overcome growth limitations in n-depleted soils. the molecular mechanism by which free-living, n(2)-fixing bacteria promote plant growth is still a matter of debate. by inoculating n-depleted tomato (lycopersicon esculentum mill.) plants with azospirillum brasilense or azoarcus sp. we could demonstrate the induction of the root nh(+)(4)-transporter gene, leamt1;2 (l. esculentum ammonium transporter 1;2), indicating that ba ... | 2002 | 12111224 |
| increased pigment and lipid content, lipid variety, and cell and population size of the microalgae chlorella spp. when co-immobilized in alginate beads with the microalgae-growth-promoting bacterium azospirillum brasilense. | three strains of the freshwater microalgae used for wastewater treatment, chlorella vulgaris and chlorella sorokiniana co-immobilized separately in alginate beads with the microalgae-growth-promoting bacterium azospirillum brasilense cd, resulted in significant changes in microalgal-population size, cell size, cell cytology, pigment, lipid content, and the variety of fatty acids produced in comparison with microalgae immobilized in alginate without the bacterium. cells of c. vulgaris utex 2714 d ... | 2002 | 12166678 |
| removal of ammonium and phosphorus ions from synthetic wastewater by the microalgae chlorella vulgaris coimmobilized in alginate beads with the microalgae growth-promoting bacterium azospirillum brasilense. | coimmobilization of the freshwater microalga chlorella vulgaris in alginate beads with the microalgae growth-promoting bacterium azospirillum brasilense under semi-continuous synthetic wastewater culture conditions significantly increased the removal of ammonium and soluble phosphorus ions compared to immobilization of the microalgae alone. in continuous or batch cultures removal of these ions followed a similar trend but was less efficient than in semi-continuous culture. it is proposed that co ... | 2002 | 12171390 |
| diversity of azospirillum strains isolated from rice plants grown in saline and nonsaline sites of coastal agricultural ecosystem. | the diversity of indigenous azospirillum spp. associated with rice cultivated along the coastline of tamil nadu was analyzed. twelve sites with varying soil characteristics such as salinity, texture, and the host variety were chosen. of the 402 strains isolated using nfb media, 302 were confirmed to be azospirillum spp. and subjected to dna polymorphism analysis using pcr-rflp of 16s rdna. they were also screened for their salt tolerance and microaerobic n2-fixing-dependent growth. on species id ... | 2002 | 12209252 |
| sensitivity function-based model reduction: a bacterial gene expression case study. | mathematical models used to predict the behavior of genetically modified organisms require 1). a (rather) large number of state variables, and 2). complicated kinetic expressions containing a large number of parameters. since these models are hardly identifiable and of limited use in model-based optimization and control strategies, a generic methodology based on sensitivity function analysis is presented to reduce the model complexity at the level of the kinetics, while maintaining high predicti ... | 2002 | 12209775 |
| short term effects of glomus claroideum and azospirillum brasilense on growth and root acid phosphatase activity of carica papaya l. under phosphorus stress. | arbuscular mycorrhizal fungi (amf) are able to increase root enzymatic activity of acid and alkaline phosphatases. however, the role of amf on phosphatase activity has not been reported in papaya (carica papaya l.), which is frequently established at places with soil phosphorus (p) deficiencies. the goals of this research were to determine the effect of glomus claroideum (gc), and plant growth promoting rhizobacterium azospirillum brasilense strain vs7 [ab]) on root phosphatase activity and seed ... | 2002 | 17061513 |
| molecular diversity of diazotrophs in oligotrophic tropical seagrass bed communities. | denaturing gradient gel electrophoresis (dgge) was employed to resolve pcr-amplified nifh sequences from vegetated and unvegetated sediments from two oligotrophic seagrass bed sites on san salvador island, bahamas, in order to assess diazotroph species composition. all dgge profiles from these sites showed the same prominent bands. these bands were sequenced, yielding 67 different nifh sequences, which were used in phylogenetic reconstructions. most sequences were from anaerobes, but some were a ... | 2002 | 19709190 |
| different evolutionary constraints on chemotaxis proteins chew and chey revealed by heterologous expression studies and protein sequence analysis. | chew and chey are single-domain proteins from a signal transduction pathway that transmits information from transmembrane receptors to flagellar motors in bacterial chemotaxis. in various bacterial and archaeal species, the chew and chey genes are usually encoded within homologous chemotaxis operons. we examined evolutionary changes in these two proteins from distantly related proteobacterial species, escherichia coli and azospirillum brasilense. we analyzed the functions of divergent chew and c ... | 2003 | 12511501 |
| 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 |
| application of emission mössbauer spectroscopy to the study of cobalt coordination in the active centers of bacterial glutamine synthetase. | 2003 | 14870610 | |
| effect of root exudates on the exopolysaccharide composition and the lipopolysaccharide profile of azospirillum brasilense cd under saline stress. | the effect of wheat root exudates on the exopolysaccharide (eps) composition and the lipopolysaccharide (lps) profile of azospirillum brasilense cd under saline stress was studied. eps of a. brasilense cd was composed of glucose (47%), mannose (3%), xylose (4%), fucose (28%), rhamnose (6%), arabinose (1%) and galactose (11%). under saline stress, a. brasilense produced a totally different eps, composed mainly of galactose. root exudates induced changes in a. brasilense eps composition only under ... | 2003 | 12594023 |
| catalytic properties of an endogenous beta-lactamase responsible for the resistance of azospirillum lipoferum to beta-lactam antibiotics. | azospirillum lipoferum rg20, a nitrogen-fixing bacterium found in all kind of soils, was found to be naturally resistant to penicillins and cephalosporins. 6-beta-bromopenicillanic acid, an irreversible inhibitor of serine-beta-lactamases, completely abolished this resistance. a beta-lactamase was purified 518-fold from a cell-free extract of a. lipoferum rg20. a single band on sds-page (apparent molecular mass 31000 da) and on isoelectric focussing (pi9.35) was observed with the purified protei ... | 2003 | 12624206 |
| [atypical r-s dissociation in azospirillum brasilense]. | it was found that atypical r-s dissociation in the type strain a. brasilense sp7 is not accompanied by drastic changes in the carbohydrate moieties of bacterial lipopolysaccharides but is rather due to different contributions of two o-specific polysaccharides (found in both r and s dissociants) to the age-dependent architectonics of the cell surface. | 2003 | 12698793 |
| transformation of azospirillum brasilense cd with an acc deaminase gene from enterobacter cloacae uw4 fused to the tet r gene promoter improves its fitness and plant growth promoting ability. | it has been reported that pgpb, containing acc deaminase, can cleave the plant ethylene precursor acc and thereby lower ethylene concentration in a developing or stressed plant, protecting it against the deleterious effects of stress ethylene and facilitating the formation of longer roots. in a previous work we have demonstrated expression of the acc deaminase gene ( acds) from enterobacter cloacae uw4 under the control of the lac promoter in azospirillum brasilense cd. with the inference that a ... | 2003 | 12739073 |
| an azospirillum brasilense tn5 mutant with modified stress response and impaired in flocculation. | the analysis of an a. brasilense tn5 mutant shows significant phenotypic differences compared to the wild type isogenic strain. the transposon was located disrupting an open reading frame of 840 bp (orf280) which exhibits similarity to the universal stress protein (usp) family. the usp family encompasses proteins that are expressed as a response to cell growth arrest. the mutant revealed a pleiotrophic phenotype with respect to different stress conditions. the orf mutation results in an increase ... | 2003 | 12755478 |
| metabolic activities in azospirillum lipoferum grown in the presence of nh4+. | the utilization of some agro-industrial wastes as soil conditioners to provide free-living nitrogen-fixing bacterial populations (e.g. azospirillum spp.) with carbon and energy sources, may be an interesting perspective for agriculture. however, the presence of ammonium nitrogen in cultivated soils and/or various wastes could inhibit the growth of the nitrogen-fixing populations. the present investigation shows that growth of azospirillum lipoferum was restricted at a dissolved oxygen (do) conce ... | 2003 | 12768247 |
| quaternary structure of azospirillum brasilense nadph-dependent glutamate synthase in solution as revealed by synchrotron radiation x-ray scattering. | azospirillum brasilense glutamate synthase (glts) is the prototype of bacterial nadph-dependent enzymes, a class of complex iron-sulfur flavoproteins essential in ammonia assimilation processes. the catalytically active glts alpha beta holoenzyme and its isolated alpha and beta subunits (162 and 52 kda, respectively) were analyzed using synchrotron radiation x-ray solution scattering. the glts alpha subunit and alpha beta holoenzyme were found to be tetrameric in solution, whereas the beta subun ... | 2003 | 12777402 |
| involvement of the reserve material poly-beta-hydroxybutyrate in azospirillum brasilense stress endurance and root colonization. | when grown under suboptimal conditions, rhizobacteria of the genus azospirillum produce high levels of poly-beta-hydroxybutyrate (phb). azospirillum brasilense strain sp7 and a phbc (phb synthase) mutant strain in which phb production is impaired were evaluated for metabolic versatility, for the ability to endure various stress conditions, for survival in soil inoculants, and for the potential to promote plant growth. the carbon source utilization data were similar for the wild-type and mutant s ... | 2003 | 12788722 |
| regulation of glnb gene promoter expression in azospirillum brasilense by the ntrc protein. | in azospirillum brasilense the glnb and glna genes are clustered in an operon regulated by three different promoters: two located upstream of glnb (glnbp1-sigma(70), and glnbp2-sigma(n)) and one as yet unidentified promoter, in the glnba intergenic region. we have investigated the expression of the glnb gene promoter using glnb-lacz gene fusions, mutation analysis, heterologous expression and dna band-shift assays. deletion of the glnb promoter region showed that ntrc-binding sequences were esse ... | 2003 | 12798997 |
| wheat germ agglutinin is a growth factor for the bacterium azospirillum brasilense. | 2003 | 12856415 | |
| plant growth regulators and amino acids released by azospirillum sp in chemically defined media. | to investigate the ability of azospirillum sp., a facultative endophitic diazotrophic bacterium, to release plant growth regulators (pgr) such as polyamines, ethylene, indoleacetic acid and amino acids in both combined-n and n-free cultures. | 2003 | 12859663 |
| poly beta-hydroxybutyrate depolymerase (phaz) in azospirillum brasilense and characterization of a phaz mutant. | like many other prokaryotes, rhizobacteria of the genus azospirillum produce high levels of poly-beta-hydroxybutyrate (phb) under sub-optimal growth conditions. utilization of phb by bacteria under stress has been proposed as a mechanism that favors their compatible establishment in competitive environments. phb depolymerase (phaz) is an essential enzyme in phb degradation. the phaz gene was identified in azospirillum brasilense, cloned, sequenced, and shown to be located on the chromosome. inse ... | 2003 | 12898135 |
| [the bactericidal activity of lectins from nitrogen-fixing bacilli]. | lectins i and ii isolated from the nitrogen-fixing soil bacterium paenibacillus polymyxa 1460 were found to be able to suppress the growth of rhizobium leguminosarum 252 and bacillus subtilis 36 at nearly all the concentrations tested (from 1 to 10 micrograms/ml). lectin i was also inhibitory to azospirillum brasilense 245 and erwinia carotovora subsp. citrulis 603, while lectin ii exerted bactericidal activity against xanthomonas campestris b-610 and b-611 and a. brasilense 245. the bacillar le ... | 2003 | 12901008 |
| [effect of cultivation parameters on the composition of extracellular polysaccharide containing substances in bacterium azospirillum brasilense]. | maintenance of ph 7.0 during the fermentation period favors accumulation of high-molecular polysaccharide-containing components, the so-called lipopolysaccharide-protein and polysaccharide-lipid complexes, in the capsules and culture medium. increased ph of the culture medium to 8.0 reduced the period of exponential growth and the yield of polysaccharide-containing complexes as compared to the optimal conditions. maintenance of ph 5.5 suppressed the culture growth and polysaccharide production. ... | 2003 | 12942749 |
| phenotypic changes resulting from distinct point mutations in the azospirillum brasilense glna gene, encoding glutamine synthetase. | sequencing the glna genes of two chemically induced azospirillum brasilense glutamine synthetase mutants revealed an arg-->cys mutation, corresponding to the glutamate binding site, in one mutant and an asp-->asn mutation, corresponding to the ammonium binding site, in the second mutant. the phenotypic changes in these mutants are discussed in relation to their genotypes. | 2003 | 12957965 |
| effect of azospirillum-mediated plant growth promotion on the development of bacterial diseases on fresh-market and cherry tomato. | plant growth-promoting (pgp) activity of two azospirillum strains and their effects on foliar and vascular bacterial diseases were evaluated on fresh market and cherry tomato. | 2003 | 12969298 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| [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 | |
| 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 |