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[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 ...200717619579
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 ...200717628141
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 ...200717643894
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- ...200717766418
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.200717897221
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 ...200717899796
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 ...200717906157
[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 ...200717907410
strain-specific salt tolerance and osmoregulatory mechanisms in azospirillum brasilense.salinity stress inhibits the growth and nitrogen fixation ability of the plant growth-promoting rhizobacterium azospirillum brasilense. five strains of a. brasilense were isolated from the rhizosphere of indian cereals and grasses and identified on the basis of their phenotypic features and 16s rrna gene sequence. the five indian isolates and two standard strains of a. brasilense, sp7 and cd, showed notable differences in growth, acetylene-reducing activity under salt stress, and ability to take ...200717156127
optimal fed batch experiment design for estimation of monod kinetics of azospirillum brasilense: from theory to practice.in this paper the problem of reliable and accurate parameter estimation for unstructured models is considered. it is illustrated how a theoretically optimal design can be successfully translated into a practically feasible, robust, and informative experiment. the well-known parameter estimation problem of monod kinetic parameters is used as a vehicle to illustrate our approach. as known for a long time, noisy batch measurements do not allow for unique and accurate estimation of the kinetic param ...200717715936
electrophysical characteristics of azospirillum brasilense sp245 during interaction with antibodies to various cell surface epitopes.this work was undertaken to examine the electrooptical characteristics of cells of azospirillum brasilense sp245 during their interaction with antibodies developed to various cell surface epitopes. we used the dependences of the cell suspension optical density changes induced by electroorientation on the orienting field frequency (740, 1000, 1450, 2000, and 2800khz). cell interactions with homologous strain-specific antibodies to the a. brasilense sp245 o antigen and with homologous antibodies t ...200717723223
[changes in electrophysical characteristics of azospirillum brasilense sp7 cells during their interaction with polyclonal antibodies].electrooptical characteristics of azospirillum brasilense sp7 cells during their specific interaction with polyclonal rabbit antibodies were studied. dependence of optical density of cell suspension during electroorientation of cells from frequency of orienting field in interval 10, 100, 250, and 500 khz was evaluated. itwas shown that electrooptical (eo) characteristics of bacterial suspensions change during interaction of a. brasilense cells with antibodies, and maximal changes occur when freq ...200718038554
azospirillum zeae sp. nov., a diazotrophic bacterium isolated from rhizosphere soil of zea mays.two free-living nitrogen-fixing bacterial strains, n6 and n7(t), were isolated from corn rhizosphere. a polyphasic taxonomic approach, including morphological characterization, biolog analysis, dna-dna hybridization, and 16s rrna, cpn60 and nifh gene sequence analysis, was taken to analyse the two strains. 16s rrna gene sequence analysis indicated that strains n6 and n7(t) both belonged to the genus azospirillum and were closely related to azospirillum oryzae (98.7 and 98.8 % similarity, respect ...200718048728
[stabilizing effect of azospirillum lectins on beta-glucosidase activity].lectins from the surface of azospirillum brasilense sp7 and azospirillumn brasilense sp7.2.3 (a mutant with impaired lectin activity) were shown to induce a stabilizing effect on the activity of almond beta-glucosidase under conditions of thermoinactivation and proteolytic enzyme treatment. differences were revealed in the influence of lectins with various antigenic properties. our results indicate that the effects of lectins on the catalytic activity of the enzyme are mainly associated with con ...200718173106
ternary complex formation between amtb, glnz and the nitrogenase regulatory enzyme drag reveals a novel facet of nitrogen regulation in bacteria.ammonium movement across biological membranes is facilitated by a class of ubiquitous channel proteins from the amt/rh family. amt proteins have also been implicated in cellular responses to ammonium availability in many organisms. ammonium sensing by amt in bacteria is mediated by complex formation with cytosolic proteins of the p(ii) family. in this study we have characterized in vitro complex formation between the amtb and p(ii) proteins (glnb and glnz) from the diazotrophic plant-associative ...200718028310
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 ...200717329796
[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 ...200718297874
[endophytic and epiphytic strains of azospirillum brazilense respond differently to heavy metal stress]. 200718297885
effect of inorganic nitrogenous fertilizer on productivity of recently reclaimed saline sodic soils with and without biofertilizer.saline sodic soils after reclamation become infertile due to leaching of most of the nutrients along with salts from the rooting medium. microbes can play a vital role in the productivity improvement of such soils. in this study a saline sodic field having ec, 6.5 ds m(-1), ph, 9.1 and gypsum requirement (gr) 3.5 tons acre(-1) was reclaimed by applying gypsum at the rate of 100% gr. rice and wheat crops were transplanted/sown for three consecutive years. inorganic nitrogenous fertilizer was used ...200719070163
ex vitro survival and early growth of alpinia purpurata plantlets inoculated with azotobacter and azospirillum .the survival rate, shoot and root dry mass, shout number, plant growth, stem height and diameter, number of leaves and root length were measured in micropropagated plantlets of alpinia purpurata (red ginger) inoculated with azospirillum sp. 11b and azotobacter sp. pachaz 008 at 10(7), 10(8) and 10(9) cells cm(-3) using a complete randomized experimental design. inoculation ofa. purpurata plantlets with the azospirillum sp. 11b or azotobacter sp. pachaz 008 strains induced larger stem diameter, r ...200719090169
[dynamics of the changes of electrophysical properties of azospirillum brasilense sp7 cells at their binding with wheat germ agglutinin].the electrooptical properties of azospirillum brasilense sp7 cell suspensions have been studied at a specific interaction with wheat germ agglutinin (wga), using the dependences between the changes of optical densities of cell suspensions at the electric orientation of cells and the orienting field frequencies of 740, 1000, 1450, 2000, and 2800 khz. it was shown that the electrooptical (eo) properties of cell suspensions changed at the interaction ofa. brasilense sp7 cells with wga and that the ...200819137717
studies on production and characterization of enriched urban waste composts and their influence on crops productivity.enriched compost produced with use of municipal solid wastes (msw) recorded narrow c:n ratio at the end of decomposition period than municipal solid wastes decomposed without enrichers. to enhance the decomposition rate, quality of municipal solid wastes and enrichers/amendments are found very significant for production of compost. nutrient content particularly nitrogen, phosphorus and potassium could be enhanced with addition of organic amendment/enrichers. response of different crops for compo ...200819192932
endophytic bacteria in the rice plant.endophytic bacteria are defined as bacteria detected inside surface-sterilized plants or extracted from inside plants and having no visibly harmful effects on the plants. various kinds of endophytic bacteria, such as pantoea, methylobacterium, azospirillum, herbaspirillum, burkholderia and rhizobium etc., have been found inside rice plants. this minireview summarizes and discusses recent studies of endophytic bacteria residing in rice plants, focusing on flora, origin, movement, and interaction ...200821558696
enhanced micropropagation response and biocontrol effect of azospirillum brasilense sp245 on prunus cerasifera l. clone mr.s 2/5 plants.inoculation with azospirillum brasilense sp245 exerts beneficial effects on micropropagated plants of prunus cerasifera l. clone mr.s 2/5, as seen in the results of a comparative analysis of inoculated and non-inoculated explants, during both the rooting and acclimatation phases. the presence of azospirillum brasilense sp245 increased root system, root hair biomass production and apical activity. although the presence of the bacteria had a positive effect on rooting, the addition of indolebutyri ...200818358553
[role of the clasping-leaved pondweed (potamogeton perfoliatus) polysaccharides in formation of its bacterial environment].the effect of the polysaccharides of clasping-leaved pondweed (potamogeton perfioliatus) on the formation of a bacteriocenosis of this plant was demonstrated by research on chemoreception, relative surface hydrophobicity, and the growth characteristics of the members of five bacterial genera abundant in this microbiocenosis. the plant heteropolysaccharides of anionic and cationic nature were found to participate in selective stimulation or inhibition of growth of some microbial groups in surroun ...200818365727
effects of rhizodeposition of non-transgenic and transplastomic tobaccos on the soil bacterial community.the effect of root-released compounds of transplastomic tobacco (nicotiana tabacum) on the soil bacterial community structure, and their potential to support horizontal gene transfer (hgt) to bacteria have been studied. soil microcosms were exposed to root-released compounds collected from transplastomic and non-transgenic tobacco cultivars. cluster analysis of automated ribosomal intergenic spacer analysis (arisa) profiles of the soil bacterial community after 48 h incubation grouped the transg ...200818384726
different responses of the glnb and glnz proteins upon in vitro uridylylation by the azospirillum brasilense glnd protein.azospirillum brasilense is a diazotroph found in association with important agricultural crops. in this organism, the regulation of nitrogen fixation by ammonium ions involves several proteins including the uridylyltransferase/uridylyl-removing enzyme, glnd, which reversibly uridylylates the two pii proteins, glnb and glnz, in response to the concentration of ammonium ions. in the present study, the uridylylation/deuridylylation cycle of a. brasilense glnb and glnz proteins by glnd was reconstit ...200818392451
azospirillum rugosum sp. nov., isolated from oil-contaminated soil.the taxonomic status of a light-orange-coloured bacterial isolate from an oil-contaminated soil sample was characterized by using a polyphasic taxonomic approach. comparative analysis of 16s rrna gene sequences demonstrated that the isolate belonged phylogenetically to the genus azospirillum, with azospirillum canadense, azospirillum brasilense and azospirillum doebereinerae as its closest phylogenetic relatives (97.3, 97.0 and 97.0 % similarity, respectively). dna-dna pairing studies showed tha ...200818398202
physical organization and phylogenetic analysis of acdr as leucine-responsive regulator of the 1-aminocyclopropane-1-carboxylate deaminase gene acds in phytobeneficial azospirillum lipoferum 4b and other proteobacteria.the phytostimulatory alphaproteobacterium azospirillum lipoferum 4b exhibits the plant-beneficial gene acds, which enables deamination of the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (acc). here, we show that acds is in the vicinity of acdr, a homolog to leucine-responsive regulator lrp, in a. lipoferum 4b and most other acds+ proteobacteria. unlike in beta- and gammaproteobacteria, acds (and acdr) is preferentially located on symbiotic islands and plasmids in alphaproteobacteria ...200818400007
responses of azospirillum brasilense to nitrogen deficiency and to wheat lectin: a diffuse reflectance infrared fourier transform (drift) spectroscopic study.for the rhizobacterium azospirillum brasilense, the optimal nutritional range of c:n ratios corresponds to the presence of malate (ca. 3 to 5 g l(-1) of its sodium salt) and ammonium (ca. 0.5 to 3 g l(-1) of nh4cl) as preferred carbon and nitrogen sources, respectively. this microaerophilic aerotactic bacterium is known to have a narrow optimal oxygen concentration range of ca. 3 to 5 microm, which is 1.2% to 2% of oxygen solubility in air-saturated water under normal conditions. in this work, t ...200818437449
microbial community response to a release of neat ethanol onto residual hydrocarbons in a pilot-scale aquifer tank.the microbial community response to a neat ethanol release (e100, 76 l) onto residual hydrocarbons in sandy soil was evaluated in a continuous-flow 8 m(3) pilot-scale aquifer tank, simulating a release at a bulk fuel terminal. microbial genotypic shifts were assessed using quantitative real-time pcr analysis. high ethanol concentrations in the capillary fringe at potentially toxic levels, exceeding 100,000 mg l(-1), were tolerated by the microbial community. the high biochemical oxygen demand ex ...200818484998
[study of immunochemical heterogeneity of azospirillum brasilense lipopolysaccharides].a comparative immunochemical analysis of lipopolysaccharides (lps) in azospirillum brasilense model strains sp7 and sp245 and in mutants with transformed somatic antigens has been performed. according to the results of a complex of various immunochemical methods, including studies with polyclonal antibodies against the lps these bacteria, their lps consist of an assembly of macromolecules with different antigenic characteristics. two types of o-specific polysaccharides (o-ps) are present in the ...200818522320
[effects of nitrogen deficiency and wheat lectin on the composition and structure of some biopolymers of azospirillum brasilense sp245]. 200818522332
aerobic nitric oxide production by azospirillum brasilense sp245 and its influence on root architecture in tomato.the major feature of the plant-growth-promoting bacteria azospirillum brasilense is its ability to modify plant root architecture. in plants, nitric oxide (no) mediates indole-3-acetic acid (iaa)-signaling pathways leading to both lateral (lr) and adventitious (ar) root formation. here, we analyzed aerobic no production by a. brasilense sp245 wild type (wt) and its mutants faj009 (iaa-attenuated) and faj164 (periplasmic nitrate reductase negative), and its correlation with tomato root-growth-pro ...200818533840
structural analysis of the o-antigen of the lipopolysaccharide from azospirillum lipoferum sr65.a neutral o-polysaccharide was obtained by mild acid degradation of the lipopolysaccharide isolated by phenol/water extraction from the asymbiotic diazotrophic rhizobacterium azospirillum lipoferum sr65. the following structure of the o-polysaccharide was established by composition and methylation analyses, smith degradation, and (1)h and (13)c nmr spectroscopy, including a 2d roesy experiment:200818561903
an extra-cytoplasmic function sigma factor and anti-sigma factor control carotenoid biosynthesis in azospirillum brasilense.strains sp7 and cd of azospirillum brasilense, a plant growth-promoting rhizobacterium, differ in synthesis of carotenoids. while colonies of strain sp7 have a white-cream colour on plates, colonies of strain cd are orange-pink coloured because of the synthesis of carotenoids. screening of a mini-tn5 mutant library of a. brasilense sp7 revealed two orange-pink-coloured mutants that produced carotenoids. cloning and sequencing of the tn5 flanking region in both the carotenoid-producing mutants of ...200818599837
activity of two catabolic enzymes of the phosphogluconate pathway in mesquite roots inoculated with azospirillum brasilense cd.the mesquite amargo (prosopis articulate), one of the main nurse trees of the sonoran desert in mexico, is responsible for major, natural re-vegetation processes. it exudes gluconic acid in root exudates, a favorite carbon source for the plant growth-promoting bacterium azospirillum brasilense. two enzymes, gluconokinase (ec 2.7.1.12) and 6-phosphogluconate dehydrogenase (ec 1.1.1.44), participating in the phosphogluconate pathway, are active in the bacteria. bacterial 6-phosphogluconate dehydro ...200818619846
duplication of plasmid-borne nitrite reductase gene nirk in the wheat-associated plant growth-promoting rhizobacterium azospirillum brasilense sp245.in the plant growth-promoting rhizobacterium azospirillum brasilense sp245, nitric oxide produced by denitrification could be a signal involved in stimulation of root branching, and the dissimilatory nitrite reductase gene nirk is upregulated on wheat roots. here, it was found that sp245 did not contain one copy of nirk but two (named nirk1 and nirk2), localized on two different plasmids, including one plasmid prone to rearrangements. their deduced protein sequences displayed 99.2% identity but ...200818624646
associative diazotrophic bacteria in grass roots and soils from heavy metal contaminated sites.this work aimed to evaluate density of associative diazotrophic bacteria populations in soil and grass root samples from heavy metal contaminated sites, and to characterize isolates from these populations, both, phenotypically (zinc, cadmium and nacl tolerance in vitro, and protein profiles) and genotypically (16s rdna sequencing), as compared to type strains of known diazotrophic species. densities were evaluated by using nfb, fam and jnfb media, commonly used for enrichment cultures of diazotr ...200819039496
analysis of microbial community during biofilm development in an anaerobic wastewater treatment reactor.the formation, structure, and biodiversity of a multispecies anaerobic biofilm inside an upflow anaerobic sludge bed (uasb) reactor fed with brewery wastewater was examined using complementary microbial ecology methods such us fluorescence in situ hybridization (fish), denaturing gradient gel electrophoresis (dgge), and cloning. the biofilm development can be roughly divided into three stages: an initial attachment phase (0-36 h) characterized by random adhesion of the cells to the surface; a co ...200818034358
recent advances in nitrogen-fixing acetic acid bacteria.nitrogen is an essential plant nutrient, widely applied as n-fertilizer to improve yield of agriculturally important crops. an interesting alternative to avoid or reduce the use of n-fertilizers could be the exploitation of plant growth-promoting bacteria (pgpb), capable of enhancing growth and yield of many plant species, several of agronomic and ecological significance. pgpb belong to diverse genera, including azospirillum, azotobacter, herbaspirillum, bacillus, burkholderia, pseudomonas, rhiz ...200818177965
thalassobaculum litoreum gen. nov., sp. nov., a member of the family rhodospirillaceae isolated from coastal seawater.a gram-negative, facultatively anaerobic strain with slightly curved and straight rod-shaped cells, strain cl-gr58(t), was isolated from coastal seawater (near gori, korea). analyses of the 16s rrna gene sequence revealed that strain cl-gr58(t) belonged to the family rhodospirillaceae with azospirillum lipoferum as its closest relative (gene sequence similarity of 90.9 %). phylogenetic analyses of the 16s rrna gene sequences showed that strain cl-gr58(t) was not associated with any known genera ...200818218953
structural analysis of the o-polysaccharide from the lipopolysaccharide of azospirillum brasilense s17.a mixture of two structurally distinct neutral o-polysaccharides was obtained by mild acid degradation of the lipopolysaccharide isolated by the phenol/water extraction from the asymbiotic diazotrophic rhizobacterium azospirillum brasilense s17. the following structures of the o-polysaccharides were established by composition and methylation analyses, smith degradation, and 1h and 13c nmr spectroscopy, including a 2d noesy experiment: [formula: see text] where l-rha2me stands for 2-o-methyl-l-rh ...200818226805
organization of the ipdc region regulates iaa levels in different azospirillum brasilense strains: molecular and functional analysis of ipdc in strain sm.presence of the indole-3-pyruvic acid pathway (ipya) of indole-3-acetic acid (iaa) biosynthesis was demonstrated by identifying the ipdc gene encoding indole-3-pyruvate decarboxylase (ipdc) in azospirillum brasilense strain sm. comparison with other a. brasilense strains, sp7 and sp245, revealed homology in the gene and its 5' regulatory region. the 3' region of strain sm carries a truncated iaac gene implicated in controlling iaa biosynthesis in strain sp245. while the ipdc transcript could be ...200818248455
characterization of a novel lipid a structure isolated from azospirillum lipoferum lipopolysaccharide.the structure of lipid a from azospirillum lipoferum, a plant-growth-promoting rhizobacterium, was investigated. it was determined by chemical analysis, mass spectrometric methods, as well as 1d and 2d nmr spectroscopy. because of the presence of substituents, the investigated lipid a differs from typical enterobacterial lipid a molecules. its backbone is composed of a beta-(1,6)-linked d-glucosamine disaccharide but lacks phosphate residues. moreover, the reducing end of the backbone (position ...200818258221
function of a chemotaxis-like signal transduction pathway in modulating motility, cell clumping, and cell length in the alphaproteobacterium azospirillum brasilense.a chemotaxis signal transduction pathway (hereafter called che1) has been previously identified in the alphaproteobacterium azospirillum brasilense. previous experiments have demonstrated that although mutants lacking cheb and/or cher homologs from this pathway are defective in chemotaxis, a mutant in which the entire chemotaxis pathway has been mutated displayed a chemotaxis phenotype mostly similar to that of the parent strain, suggesting that the primary function of this che1 pathway is not t ...200818641130
[chemical and serological studies of liposaccharides of bacteria of the genus azospirillum].the analysis of the lipopolysaccharides (lps) of nine strains of azospirilla revealed the presence of the characteristic components of these glycopolymers: carbohydrates, hydroxylated fatty acids, and 2-keto-3-deoxyoctonic acid (kdo). sds electrophoresis revealed the heterogeneous nature and the strains differences in the ratio of the molecular s and r forms present in the lps. polyclonal rabbit antibodies (ab) were obtained against the isolated lps(cd), lps(sp59b), lps(sp7), lps(s17), and lps(k ...200818683652
[the effect of mutations in the synthesis of lipopolysaccharides and calcofluor-binding polysaccharides on biofilm formation by azospirillum brasilense].the thickness and antigenic properties of biofilms produced by azospirillum brasilense sp245 and its mutants deficient in the synthesis of lipopolysaccharides (lps) and calcofluor-binding polysaccharides (cbps) at the interface between water and hydrophilic or hydrophobic solid surfaces were compared. the mutants deficient in acidic lpsi synthesis produce thicker biofilms on hydrophilic surfaces. biofilms produced on hydrophobic surfaces by bacteria that are unable to synthesize cbps are less pr ...200818683653
mutation in a gene encoding anti-sigma factor in a. brasilense confers tolerance to elevated temperature, antibacterial peptide and peg-200 via carotenoid synthesis.azospirillum brasilense sp7 has been shown to overproduce carotenoids if the anti-sigma factor (anti-sigma(e))-encoding gene is inactivated. the anti-sigma mutant (car-1) of a. brasilense sp7 was more tolerant to the stresses generated by elevated temperature (40 degrees c), peg-200 (30 mg ml(-1)) and the antibacterial agent polymyxin-b (pmb, 25 microg ml(-1)) but not to elevated salinity (15 mg ml(-1)). inhibition of carotenoid synthesis by diphenylamine inhibited the ability of the mutant to t ...200818754787
a quorum-quenching approach to identify quorum-sensing-regulated functions in azospirillum lipoferum.a quorum-quenching approach was exploited in order to identify functions regulated by quorum-sensing (qs) in the plant growth-promoting bacterium azospirillum lipoferum. the attm lactonase from agrobacterium tumefaciens was shown to enzymatically inactivate n-acyl homoserine lactones (ahls) produced by two a. lipoferum strains. the targeted analysis of several phenotypes revealed that in strain b518, a rice endophyte, ahl inactivation abolished pectinase activity, increased siderophore synthesis ...200818790051
joint immobilization of plant growth-promoting bacteria and green microalgae in alginate beads as an experimental model for studying plant-bacterium interactions.a simple, quantitative experimental model, offering a convenient and basic approach to studies of plant-bacterium interactions, is proposed. this involves immobilizing a unicellular, freshwater microalga, a chlorella species, serving as the plant, with a plant growth-promoting bacterium, an azospirillum species, in small alginate beads to allow close interaction and to avoid external interference from bacterial contaminants.200818791009
colonization and nitrogenase activity of triticum aestivum (cv. baccross and mahdavi) to the dual inoculation with azospirillum brasilense and rhizobium meliloti plus 2,4-d.the potential enhancement of root colonization and nitrogenase activity of wheat cultivars (baccross and mahdavi) was studied with application of two azospirillum brasilense strains (native and sp7) co-inoculated with two rhizobium meliloti strains (native and dsmz 30135). the results indicated that the colonization was different due to the strains and cultivars of wheat were used. native a. brasilense colonized wheat root better than sp7 strain. however, baccross cv. reacted better with native ...200818819640
field evaluation of the interaction common bean genotype, rhizobacteria and environmental factors in cuba. 200818831273
evaluation of bean (phaseolus vulgaris) seeds inoculation with rhizobium phaseoli and plant growth promoting rhizobacteria on yield and yield components.to study the effect of co-inoculation with plant growth-promoting rhizobacteria (pgpr) and rhizobium, on yield and yield components of common bean (phaseolus vulgaris l.) cultivars was investigated in 2 consecutive years under field condition of plant growing evidence indicates that soil beneficial bacteria can positively affect symbiotic performance of rhizobia. pgpr strains pseudomonas fluorescens p-93 and azospirillum lipoferum s-21 as well as two highly effective rhizobium strains were used ...200818983036
bacteriophage prevalence in the genus azospirillum and analysis of the first genome sequence of an azospirillum brasilense integrative phage.the prevalence of bacteriophages was investigated in 24 strains of four species of plant growth-promoting rhizobacteria belonging to the genus azospirillum. upon induction by mitomycin c, the release of phage particles was observed in 11 strains from three species. transmission electron microscopy revealed two distinct sizes of particles, depending on the identity of the azospirillum species, typical of the siphoviridae family. pulsed-field gel electrophoresis and hybridization experiments carri ...200818065619
azospirillum brasilense sp7 produces an outer-membrane lectin that specifically binds to surface-exposed extracellular polysaccharide produced by the bacterium.azospirillum sp promotes the growth of many important crop plants. we demonstrated lectin binding activity in outer-membrane protein extracts of a. brasilense sp7 by hemagglutination assays. the lectin specifically recognised the exopolysaccharide (eps) produced by aggregated cells. affinity chromatography using eps-sepharose was used to identify a 67 kda outer-membrane lectin (oml) that recognised a binding region in the extracellular polysaccharide. results show the specific recognition and bi ...200818094958
studies on rhizosphere microbial diversity of some commercially important medicinal plants.a preliminary study was made on four medicinal plants viz., ocimum sanctum l., coleus forskholii briq, catharanthus roseus (l.) g. don. and aloe vera in order to identify and enumerate the rhizosphere, non-rhizosphere and diazotrophic microorganisms in soil. the diazotrophic bacterial population studied includes azospirillum, azotobacter and pseudomonas. the rhizosphere bacterial populations were 23.33 x 10(6)g(-1) in o. sanctum followed by c. roseus (20.46 x 10(6)g(-1)), a. vera (18.44 x 10(6)g ...200817951032
an ipdc gene knock-out of azospirillum brasilense strain sm and its implications on indole-3-acetic acid biosynthesis and plant growth promotion.the indole-3-pyruvate decarboxylase gene (ipdc), coding for a key enzyme of the indole-3-pyruvic acid pathway of iaa biosynthesis in azospirillum brasilense sm was functionally disrupted in a site-specific manner. this disruption was brought about by group ii intron-based targetron gene knock-out system as other conventional methods were unsuccessful in generating an iaa-attenuated mutant. intron insertion was targeted to position 568 on the sense strand of ipdc, resulting in the knock-out strai ...200817952626
chlorella sorokiniana utex 2805, a heat and intense, sunlight-tolerant microalga with potential for removing ammonium from wastewater.in the summer of 2003, a microalga strain was isolated from a massive green microalgae bloom in wastewater stabilization ponds at the treatment facility of la paz, b.c.s., mexico. prevailing environmental conditions were air temperatures over 40 degrees c, water temperature of 37 degrees c, and insolation of up to 2400 micromol m2 s(-1) at midday for several hours at the water surface for four months. the microalga was identified as chlorella sorokiniana shih. et krauss, based on sequencing its ...200818024023
effects of the inoculation of burkholderia vietnamensis and related endophytic diazotrophic bacteria on grain yield of rice.during a survey of endophytic diazotrophic bacteria associated with different rice varieties in tamilnadu, some "endophytes" were obtained. thirteen bacterial isolates from surface-sterilized roots and shoots were obtained in pure culture, which produced indole acetic acid (iaa) and reduced acetylene to ethylene. polymerase chain reaction (pcr) amplification confirmed the presence of nif-h gene in all the isolates. morphological, biochemical, and molecular characteristics indicated that all of t ...200817406771
changes in motility of the rhizobacterium azospirillum brasilense in the presence of plant lectins.the plant-beneficial bacterium azospirillum brasilense can swim in liquids and swarm or migrate with the formation of microcolonies in soft media. to get closer to understanding the influence of natural environments on a. brasilense motility, we studied the individual and social movement of the bacterium in the presence of various plant lectins. the lectins with specificity for n-acetyl-beta-d-glucosamine oligomers (wheat germ, solanum tuberosum and ulex europeus agglutinins) decreased a. brasil ...200917317126
changes in azospirillum brasilense motility and the effect of wheat seedling exudates.the rhizobacterium azospirillum brasilense sp245 swims, swarms (swa(+) phenotype) or, very rarely, migrates with the formation of granular macrocolonies (gri(+) phenotype). our aims were (i) to identify sp245 mutants that swarm faster than the parent strain or differ from it in the mode of spreading and (ii) to compare the mutants' responses to wheat seedling exudates. in isotropic liquid media, the swimming speeds of all motile a. brasilense strains were not influenced by the exudates. however, ...200917707621
mutation in a d-alanine-d-alanine ligase of azospirillum brasilense cd results in an overproduction of exopolysaccharides and a decreased tolerance to saline stress.bacteria of the genus azospirillum are free-living nitrogen-fixing, rhizobacteria that are found in close association with plant roots, where they exert beneficial effects on plant growth and yield in many crops of agronomic importance. unlike other bacteria, little is known about the genetics and biochemistry of exopolysaccharides in azospirillum brasilense. in an attempt to characterize genes associated with exopolysaccharides production, we generated an a. brasilense cd tn5 mutant that showed ...200919025567
expression and functional analysis of aminotransferase involved in indole-3-acetic acid biosynthesis in azospirillum brasilense yu62.in this study, atrc (a novel gene from azospirillum brasilense identified in our laboratory) was expressed in escherichia coli, and sds-page analysis of the expressed atrc revealed the apparent molecular weight of 45 kd. when analyzed under non-denaturing page conditions and using l-tryptophan as a substrate, the purified atrc protein exhibited aminotransferase activity, while crude protein extracts from a. brasilense yu62 showed two activity bands with molecular masses estimated as 44 and 66 kd ...200919232053
the wzm gene located on the prhico plasmid of azospirillum brasilense sp7 is involved in lipopolysaccharide synthesis.several genes involved in the interaction between azospirillum brasilense sp7 and plants are located on the prhico plasmid. here we report the characterization of an sp7 mutant strain with impairment of the prhico-located gene wzm. this gene encodes an inner-membrane component of an atp-binding cassette (abc) transporter with similarity to transporters involved in surface polysaccharide export. indeed, sds-page revealed that lps synthesis is affected in the wzm mutant. no significant differences ...200919246750
mobile elements of an azospirillum brasilense sp245 85-mda plasmid involved in replicon fusions.sequence analysis of approximately 25kb of an azospirillum brasilense sp245 85-mda ( approximately 142kb) plasmid, p85, identified two novel is elements mediating p85 fusions with a suicide plasmid vector, pjff350. these is elements, 1465-bp isazba1 and 1112-bp isazba3, belong to the is256 family and to the is5 family/is903 group, respectively. truncated isazba2 from the isl3 family was found near one of the copies of isazba1 that flank pjff350 in p85::pjff350. as another factor potentially cont ...200919249329
azospirillum palatum sp. nov., isolated from forest soil in zhejiang province, china.a gram-negative bacterium designated ww 10(t) was isolated by plating dilutions from forest soil in zhejiang province, china. strain ww 10(t) was investigated by polyphasic taxonomic study including phenotypic and phylogenetic analysis. cells of ww 10(t) were gram-negative, strictly aerobic, motile with peritrichous flagella and rod-shaped. the strain grew optimally at 30-37 masculinec and ph 6.0-8.0. the major fatty acids were c(18:1)omega7c, cyclo-c(19:0) omega8c and c(16:0). the respiratory q ...200919282627
the pii superfamily revised: a novel group and evolutionary insights.the pii proteins compose a superfamily of signal transducers with fundamental roles in the nitrogen metabolism of prokaryotic organisms. they act at different cellular targets, such as ammonia transporters, enzymes, and transcriptional factors. these proteins are small, highly conserved, and well distributed among prokaryotes. the current pii classification is based on sequence similarity and genetic linkage. our work reviewed this classification through an extensive analysis of pii homologues d ...200919296042
revised structure of the repeating unit of the o-specific polysaccharide from azospirillum lipoferum strain spbr17.a neutral o-polysaccharide liberated by mild acid hydrolysis of a lipopolysaccharide isolated from azospirillum lipoferum spbr17 was investigated using 1d and 2d (1)h and (13)c nmr spectroscopy, including hsqc, hmbc, and noesy as well as sds-page electrophoresis along with sugar and methylation analyses. the structure of the o-specific polysaccharide repeating unit was established as follows: [formula: see text]. the presented structure is a revised version of the formula that was published earl ...200919324329
azospirillum picis sp. nov., isolated from discarded tar.a polyphasic taxonomic study was performed on a pink-coloured unknown bacterium isolated from discarded road tar. comparative analysis of the 16s rrna gene sequence demonstrated that the isolate belongs phylogenetically to the genus azospirillum with azospirillum lipoferum, a. melinis and a. rugosum as its closest phylogenetic relatives (96.7, 96.6 and 96.6 % similarity to the respective type strains). the generic assignment was confirmed on the basis of chemotaxonomic data, which revealed a fat ...200919329602
alkyl hydroperoxide reductase has a role in oxidative stress resistance and in modulating changes in cell-surface properties in azospirillum brasilense sp245.an ahpc mutant derivative of azospirillum brasilense sp245 (strain sk586) that encodes an alkyl hydroperoxide reductase was found to be more sensitive to oxidative stress caused by organic hydroperoxides compared with the wild-type. in addition, the ahpc mutant strain had multiple defects in a large array of cellular functions that were consistent with alteration of cell-surface properties, such as cell morphology in stationary phase, calcofluor white-, congo red- and lectin-binding abilities, a ...200919332821
[diverse morphological types of dormant cells and conditions for their formation in azospirillum brasilense].differences in generation of dormant forms (df) were revealed between two strains of non-sporeforming gram-negative bacteria azospirillum brasilense, sp7 (non-endophytic) and sp245 (endophytic strain). in post-stationary ageing bacterial cultures grown in a synthetic medium with a fivefold decreased initial nitrogen content, strain sp7 formed two types of cyst-like resting cells (crc). strain sp245 did not form such types of df under the same conditions. crc of the first type were formed in stra ...200919334596
gut-associated denitrification and in vivo emission of nitrous oxide by the earthworm families megascolecidae and lumbricidae in new zealand.previous studies have documented the capacity of european earthworms belonging to the family lumbricidae to emit the greenhouse gas nitrous oxide (n(2)o), an activity attributed primarily to the activation of ingested soil denitrifiers. to extend the information base to earthworms in the southern hemisphere, four species of earthworms in new zealand were examined for gut-associated denitrification. lumbricus rubellus and aporrectodea rosea (introduced species of lumbricidae) emitted n(2)o, where ...200919346358
identification of the glutamine synthetase adenylyltransferase of azospirillum brasilense.glutamine synthetase, a key enzyme in nitrogen metabolism of both prokaryotes and eukaryotes, is strictly regulated. one means of regulation is the modulation of activity through adenylylation catalyzed by adenylyltransferases. using pcr primers based on conserved sequences in glutamine synthetase adenylyltransferases, we amplified part of the glne gene of azospirillum brasilense sp7. the complete glne sequence of a. brasilense sp245 was retrieved from the draft genome sequence of this organism ...200919366628
characterization of chsa, a new gene controlling the chemotactic response in azospirillum brasilense sp7.we report, here, the characterization of a mutant strain of azospirillum brasilense sp7 impaired in surface motility and chemotactic response. presence of flagella in the mutant strain was confirmed by western blot analysis, using antisera raised against the polar and lateral flagellins, and by electron microscopy. genetic complementation and nucleotide sequencing led to the identification of a new gene, named chsa. the deduced translation product, chsa protein, contained a pas sensory domain an ...200919390839
isolation of bacterial strains from bovine fecal microflora capable of degradation of ceftiofur.ceftiofur, a third-generation cephalosporin used to treat bacterial infections in animals, is degraded in bovine feces but the specific bacteria involved are unknown. to find the bacteria involved in ceftiofur metabolism, the bovine fecal microflora was screened. twenty-one nonidentical strains of bovine fecal bacteria were isolated on media containing 1-32 microg ml(-1) of ceftiofur. the cultures were incubated with 5 microg ml(-1) ceftiofur for different times, then centrifuged and analyzed by ...200919428193
trehalose accumulation in azospirillum brasilense improves drought tolerance and biomass in maize plants.bacteria of the genus azospirillum increase the grain yield of several grass crops. in this work the effect of inoculating maize plants with genetically engineered azospirillum brasilense for trehalose biosynthesis was determined. transformed bacteria with a plasmid harboring a trehalose biosynthesis gene-fusion from saccharomyces cerevisiae were able to grow up to 0.5 m nacl and to accumulate trehalose, whereas wild-type a. brasilense did not tolerate osmotic stress or accumulate significant le ...200919459961
crystal structure of dinitrogenase reductase-activating glycohydrolase (drag) reveals conservation in the adp-ribosylhydrolase fold and specific features in the adp-ribose-binding pocket.protein-reversible adp-ribosylation is emerging as an important post-translational modification used to control enzymatic and protein activity in different biological systems. this modification regulates nitrogenase activity in several nitrogen-fixing bacterial species. adp-ribosylation is catalyzed by adp-ribosyltransferases and is reversed by adp-ribosylhydrolases. the structure of the adp-ribosylhydrolase that acts on azospirillum brasilense nitrogenase (dinitrogenase reductase-activating gly ...200919477184
comparison of rhizobacterial community composition in soil suppressive or conducive to tobacco black root rot disease.work on soils suppressive to thielaviopsis basicola-mediated tobacco black root rot has focused on antagonistic pseudomonads to date. the role of non-pseudomonas rhizosphere populations has been neglected, and whether they differ in black root rot-suppressive versus -conducive soils is unknown. to assess this possibility, tobacco was grown in a suppressive and a conducive soil of similar physicochemical properties, and rhizobacterial community composition was compared using a 16s rrna taxonomic ...200919554036
plant-microbe interactions promoting plant growth and health: perspectives for controlled use of microorganisms in agriculture.plant-associated microorganisms fulfill important functions for plant growth and health. direct plant growth promotion by microbes is based on improved nutrient acquisition and hormonal stimulation. diverse mechanisms are involved in the suppression of plant pathogens, which is often indirectly connected with plant growth. whereas members of the bacterial genera azospirillum and rhizobium are well-studied examples for plant growth promotion, bacillus, pseudomonas, serratia, stenotrophomonas, and ...200919568745
screening plant growth promoting rhizobacteria for improving seed germination, seedling growth and yield of maize.the effect of plant growth-promoting rhizobacteria (pgpr) on seed germination, seedling growth and yield of field grown maize were evaluated in three experiments. in these experiments six bacterial strains include p. putida strain r-168, p. fluorescens strain r-93, p. fluorescens dsm 50090, p. putida dsm291, a. lipoferum dsm 1691 and a. brasilense dsm 1690 were used. results of first study showed seed inoculation significantly enhanced seed germination and seedling vigour of maize. in second exp ...200919579914
enhancement of growth and nutrient uptake of rapeseed (brassica napus l.) by applying mineral nutrients and biofertilizers.for investigating the effect of chemical fertilizer as well as biofertilizers on seed yield and quality i.e. oil, protein and nutrients concentration of rapeseed (brassica napus l.), a split-plot fertilizers application experimental design in 4 replications was carried out during the 2005-2006 growing season, at the gharakheil agricultural research station in the mazandaran province of iran. rapeseed was grown as a second crop in rotation after rice. biofertilizers treatments were two different ...200919579932
in vitro interactions between the pii proteins and the nitrogenase regulatory enzymes dinitrogenase reductase adp-ribosyltransferase (drat) and dinitrogenase reductase-activating glycohydrolase (drag) in azospirillum brasilense.the activity of the nitrogenase enzyme in the diazotroph azospirillum brasilense is reversibly inactivated by ammonium through adp-ribosylation of the nitrogenase nifh subunit. this process is catalyzed by drat and is reversed by drag, and the activities of both enzymes are regulated according to the levels of ammonium through direct interactions with the p(ii) proteins glnb and glnz. we have previously shown that drag interacts with glnz both in vivo and in vitro and that drat interacts with gl ...200919131333
d-xylose degradation pathway in the halophilic archaeon haloferax volcanii.the pathway of d-xylose degradation in archaea is unknown. in a previous study we identified in haloarcula marismortui the first enzyme of xylose degradation, an inducible xylose dehydrogenase (johnsen, u., and schönheit, p. (2004) j. bacteriol. 186, 6198-6207). here we report a comprehensive study of the complete d-xylose degradation pathway in the halophilic archaeon haloferax volcanii. the analyses include the following: (i) identification of the degradation pathway in vivo following (13)c-la ...200919584053
fluctuation of microbial activities after influent load variations in a full-scale sbr: recovery of the biomass after starvation.due to variations in the production levels, a full-scale sequencing batch reactor (sbr) for post-treatment of tannery wastewater was exposed to low and high ammonia load periods. in order to study how these changes affected the n-removal capacity, the microbiology of the reactor was studied by a diverse set of techniques including molecular tools, activity tests, and microbial counts in samples taken along 3 years. the recover capacity of the biomass was also studied in a lab-scale reactor opera ...200919629470
regulation of expression and biochemical characterization of a beta-class carbonic anhydrase from the plant growth-promoting rhizobacterium, azospirillum brasilense sp7.carbonic anhydrase (ca; [ec 4.2.1.1]) is a ubiquitous enzyme catalysing the reversible hydration of co(2) to bicarbonate, a reaction that supports various biochemical and physiological functions. genome analysis of azospirillum brasilense, a nonphotosynthetic, nitrogen-fixing, rhizobacterium, revealed an orf with homology to beta-class carbonic anhydrases (cas). biochemical characteristics of the beta-class ca of a. brasilense, analysed after cloning the gene (designated as bca), overexpressing ...200919694814
rhizosphere bacterial communities associated with disease suppressiveness stages of take-all decline in wheat monoculture.the decline of take-all disease (gaeumannomyces graminis var. tritici), which may take place during wheat monocropping, involves plant-protecting, root-colonizing microorganisms. so far, however, most work has focused on antagonistic fluorescent pseudomonads. our objective was to assess the changes in rhizobacterial community composition during take-all decline of field-grown wheat. the study was based on the development and utilization of a taxonomic 16s rrna-based microarray of 575 probes, cou ...200919732350
the azospirillum brasilense sp7 noej and noel genes are involved in extracellular polysaccharide biosynthesis.azospirillum brasilense is a plant root-colonizing bacterium that exerts beneficial effects on the growth of many agricultural crops. extracellular polysaccharides of the bacterium play an important role in its interactions with plant roots. the prhico plasmid of a. brasilense sp7, also named p90, carries several genes involved in synthesis and export of cell surface polysaccharides. we generated two sp7 mutants impaired in two prhico-located genes, noej and noel, encoding mannose-6-phosphate is ...200919762447
glycogen phosphorylase is involved in stress endurance and biofilm formation in azospirillum brasilense sp7.here we report the identification of a glycogen phosphorylase (glgp) gene in the plant growth-promoting rhizobacterium azospirillum brasilense, sp7, and the characterization of a glgp marker exchange mutant of this strain. the glgp mutant showed a twofold reduction of glycogen phosphorylase activity and an increased glycogen accumulation as compared with wild-type sp7, indicating that the identified gene indeed encodes a protein with glycogen phosphorylase activity. interestingly, the glgp mutan ...200919765087
effects of colonization of a bacterial endophyte, azospirillum sp. b510, on disease resistance in rice.agriculturally important grasses contain numerous diazotrophic bacteria, the interactions of which are speculated to have some other benefits to the host plants. in this study, we analyzed the effects of a bacterial endophyte, azospirillum sp. b510, on disease resistance in host rice plants. rice plants (oryza sativa cv. nipponbare) were inoculated with b510 exhibited enhanced resistance against diseases caused by the virulent rice blast fungus magnaporthe oryzae and by the virulent bacterial pa ...200919966496
[toxicological evaluation of biopreparations on the basis of nitrogen-fixing bacteria].a comparative analysis of results of toxicological research of microbiological preparations on the basis of different species of nitrogen-fixing microorganisms of azotobacter, agrobacterium, azospirillum general and pathogenic properties of strains-producers has been carried out. a possibility to improve methodical principles of toxicological estimation and hygienic regulation of associative nitrogen-fixing microorganisms-producers and preparations on their basis in the industrial objects and en ...200920455429
[identification of azospirillum genus bacteria isolated from the spring wheat root zone].bacteria with high n2-fixing activity were isolated from the root zone of spring wheat grown on leach chernozem and soddy podzolic soil in ukrainian marshy woodlands. they were characterized by phenotypic signs and investigated with the help of molecular-genetic methods. on the basis of diagnostic signs the investigated strains were referred to azospirillum brasilense from azospirillum genus. their 3'- and 5'-thermal 16s rna hypervariable sites with length from 373 to 395 nucleotides were amplif ...200919938589
bio-filtration of trichloroethylene using diazotrophic bacterial community.biodegradation of tce was studied in a biofilter packed with wood charcoal and inoculated with diazotrophic bacterial community isolated from local soil. steady state tce removal efficiencies higher than 85% were observed up to inlet load of 2.866 g m(-3) h(-1). the maximum elimination capacity of 5.31 g m(-3) h(-1) was observed at an inlet load of more than 7.90 g m(-3) h(-1). the biofilter was sensitive to fluctuations in the process conditions but could easily recover its performance after 10 ...201019962302
a hybrid two-component system protein from azospirillum brasilense sp7 was involved in chemotaxis.we here report the sequence and functional analysis of org35 of azospirillum brasilense sp7, which was originally identified to be able to interact with nifa in yeast-two-hybrid system. the org35 encodes a hybrid two-component system protein, including n-terminal pas domains, a histidine kinase (hpk) domain and a response regulator (rr) domain in c-terminal. to determine the function of the org35, a deletion-insertion mutant in pas domain [named sp7353] and a complemental strain sp7353c were con ...201020869221
host plant secondary metabolite profiling shows a complex, strain-dependent response of maize to plant growth-promoting rhizobacteria of the genus azospirillum.most azospirillum plant growth-promoting rhizobacteria (pgpr) benefit plant growth through source effects related to free nitrogen fixation and/or phytohormone production, but little is known about their potential effects on plant physiology. these effects were assessed by comparing the early impacts of three azospirillum inoculant strains on secondary metabolite profiles of two different maize (zea mays) cultivars. after 10d of growth in nonsterile soil, maize methanolic extracts were analyzed ...201020946131
azospirillum sp. strain b510 enhances rice growth and yield.inoculation experiments with the endophytic bacterium azospirillum sp. strain b510, an isolate from surface-sterilized stems of field-grown rice, were conducted in pots in a greenhouse, and in paddy fields in hokkaido, japan. b510 significantly enhanced the growth of newly generated leaves and shoot biomass under greenhouse conditions. when rice seedlings were treated with 1×10(8) cfu ml(-1), then transplanted to paddy fields, tiller numbers and seed yield significantly increased. azospirillum s ...201021576855
diversity of nitrogenase (nifh) genes pool in soybean field soil after continuous and rotational cropping.diazotrophs diversity in soybean is a topic requiring thorough investigation since the previous researches have focused on only rice, forest, grass, water, etc. in this research, iron-only nitrogenase nifh gene was as genetic marker. pcr-rflp was used to investigate the difference of diazotrophs community diversity in the soil from the continuous cropping (cc) (the 5-yr tilling of soybean) and the rotational cropping (rc) (soybean-corn) soils in the northeast of china. a total of 36 isolates wer ...201020473958
a new p(ii) protein structure identifies the 2-oxoglutarate binding site.p(ii) proteins of bacteria, archaea, and plants regulate many facets of nitrogen metabolism. they do so by interacting with their target proteins, which can be enzymes, transcription factors, or membrane proteins. a key feature of the ability of p(ii) proteins to sense cellular nitrogen status and to interact accordingly with their targets is their binding of the key metabolic intermediate 2-oxoglutarate (2-og). however, the binding site of this ligand within p(ii) proteins has been controversia ...201020493877
effect of pesticides on soil microbial community.according to guidelines for the approval of pesticides, information about effects of pesticides on soil microorganisms and soil fertility are required, but the relationships of different structures of pesticides on the growth of various groups of soil microorganisms are not easily predicted. some pesticides stimulate the growth of microorganisms, but other pesticides have depressive effects or no effects on microorganisms. for examples, carbofuran stimulated the population of azospirillum and ot ...201020512724
endophytic bacterial diversity in roots of phragmites australis in constructed beijing cuihu wetland (china).the community structure and diversity of endophytic bacteria in reed (phragmites australis) roots growing in the beijing cuihu wetland, china was investigated using the 16s rrna library technique. primers 799f and 1492r were used to amplify the specific bacterial 16s rrna fragments successfully and construct the clone library. in total, 166 individual sequences were verified by colony pcr and used to assess the diversity of endophytic bacteria in reed roots. phylogenetic analysis revealed that 7 ...201020528944
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