| formation of pyridine nucleotides under symbiotic and non-symbiotic conditions between soybean nodules and free-living rhizobia. | enzymatic regulation of pyricline nucleotide formation, under symbiotic and non-symbiotic conditions, was analyzed using soybeans (glycine max l. cv. 'akisengoku') and rhizobia (bradyrhizobia japonicum strain a1017), respectively. it was found that levels of pyridine nucleotides in bacteroids in root nodules were different from those in free-living cells of rhizobia. this difference was associated with differences in activities of enzymes involved in the pathway from l-tryptophan to nad and nadp ... | 2002 | 12423884 |
| characterization of the norcbqd genes, encoding nitric oxide reductase, in the nitrogen fixing bacterium bradyrhizobium japonicum. | the genes norcbqd that encode the bc-type nitric oxide reductase from bradyrhizobium japonicum usda110 have been isolated and characterized. norc and norb encode the cytochrome c-containing subunit ii and cytochrome b-containing subunit i of nitric oxide reductase, respectively. norq encodes a protein with an atp/gtp-binding motif, and the predicted nord gene product shows similarity with nord from other denitrifiers. mutational analysis indicates that the two structural norc and norb genes are ... | 2002 | 12427946 |
| partial 16s rrna gene sequence diversity and numerical taxonomy of slow growing pigeonpea (cajanus cajan l millsp) nodulating rhizobia. | an investigation was carried out to determine the diversity of 30 isolates of slow growing pigeonpea nodulating rhizobia based on variations in partial sequences of the 16s rrna gene and numerical analysis of 80 phenotypic traits. phylogenetic analysis using molecular sequences of 23 isolates showed that arpe1 separated from the other isolates at an average distance of >14% divergence level. the other isolates were all within 5% divergence from each other but separated into four main groups, wit ... | 2002 | 12435494 |
| structural adaptations in a membrane enzyme that terminates endocannabinoid signaling. | cellular communication in the nervous system is mediated by chemical messengers that include amino acids, monoamines, peptide hormones, and lipids. an interesting question is how neurons regulate signals that are transmitted by membrane-embedded lipids. here, we report the 2.8 angstrom crystal structure of the integral membrane protein fatty acid amide hydrolase (faah), an enzyme that degrades members of the endocannabinoid class of signaling lipids and terminates their activity. the structure o ... | 2002 | 12459591 |
| transcriptional response of soybean suspension-cultured cells induced by nod factors obtained from bradyrhizobium japonicum usda110. | genes responding to nod factors were picked up by the application of a differential display method for soybean suspension-cultured cells. forty-five cdna fragments derived from such genes were detected. seven fragments (ssc1-ssc7) were successfully cloned. the putative product of genes corresponding to ssc1 was estimated to be a disease-resistance protein relating to the induction of the plant defense response against pathogens, and that corresponding to ssc7 was a sucrose transporter. amino aci ... | 2002 | 12461131 |
| symbiotic root nodule bacteria isolated from yam bean (pachyrhizus erosus). | a total of 25 isolates from root nodules of yam bean (pachyrhizus erosus l. urban), a tuber-producing leguminous plant, were characterized. all isolates formed effective nodules mainly on lateral roots while edible tubers were developed on the taproot. the root nodules formed were identified as the typical determinate type. by an analysis of the partial sequences of the 16s rrna gene (approximately 300 bp) of 10 strains which were selected randomly, the isolated root nodule bacteria of yam bean ... | 2002 | 12469317 |
| generating and exploiting polarity in bacteria. | bacteria are often highly polarized, exhibiting specialized structures at or near the ends of the cell. among such structures are actin-organizing centers, which mediate the movement of certain pathogenic bacteria within the cytoplasm of an animal host cell; organized arrays of membrane receptors, which govern chemosensory behavior in swimming bacteria; and asymmetrically positioned septa, which generate specialized progeny in differentiating bacteria. this polarization is orchestrated by comple ... | 2002 | 12471245 |
| mutational and transcriptional analysis of the type iii secretion system of bradyrhizobium japonicum. | sequencing the symbiotic region of bradyrhizobium japonicum revealed a gene cluster (tts) encoding a type iii secretion system (ttss) that is similar to those found in mesorhizobium loti maff303099 and rhizobium strain ngr234. in addition to genes that are likely to encode structural core components of the ttss, the cluster contains several open reading frames that are found exclusively in rhizobia or that are specific to b. japonicum. depending on the host, mutations within this cluster affecte ... | 2002 | 12481995 |
| evidence that carbon dioxide enrichment alleviates ureide-induced decline of nodule nitrogenase activity. | the hypothesis that elevated [co(2)] alleviates ureide inhibition of n(2)-fixation was tested. short-term responses of the acetylene reduction assay (ara), ureide accumulation and total non-structural carbohydrate (tnc) levels were measured following addition of ureide to the nutrient solution of hydroponically grown soybean. the plants were exposed to ambient (360 micromol mol(-1)) or elevated (700 micromol mol(-1)) [co(2)]. addition of 5 and 10 mm ureide to the nutrient solution inhibited n(2) ... | 2003 | 12495923 |
| characterization of bradyrhizobium strains isolated from soybean cultivation in thailand. | | 1997 | 12501335 |
| characterization of rhizobia that nodulate legume species of the genus lespedeza and description of bradyrhizobium yuanmingense sp. nov. | legume species belonging to the genus lespedeza are annual or perennial herb or shrub plants that grow in the northern hemisphere. they are known for the formation of root nodules, but little information is available about their microsymbionts. in this study, 58 root-nodule isolates from lespedeza spp., obtained from china and the usa, were characterized using numerical taxonomic analysis of phenotypic features, sds-page analysis of whole-cell proteins, dna-dna hybridization, 16s rrna gene seque ... | 2002 | 12508891 |
| nodulation gene regulation in bradyrhizobium japonicum: a unique integration of global regulatory circuits. | | 2003 | 12513971 |
| a host-specific bacteria-to-plant signal molecule (nod factor) enhances germination and early growth of diverse crop plants. | lipo-chitooligosaccharides (lcos), or nod factors, are host-specific bacteria-to-plant signal molecules essential for the establishment of a successful n(2)-fixing legume-rhizobia symbiosis. at submicromolar concentrations nod factors induce physiological changes in host and non-host plants. here we show that the nod factor nod bj v(c18:1,mefuc) of bradyrhizobium japonicum 532c enhances germination of a variety of economically important plants belonging to diverse botanical families: zea mays, o ... | 2003 | 12520335 |
| prediction and overview of the rpon-regulon in closely related species of the rhizobiales. | in the rhizobia, a group of symbiotic gram-negative soil bacteria, rpon (sigma54, sigman, ntra) is best known as the sigma factor enabling transcription of the nitrogen fixation genes. recent reports, however, demonstrate the involvement of rpon in other symbiotic functions, although no large-scale effort has yet been undertaken to unravel the rpon-regulon in rhizobia. we screened two complete rhizobial genomes (mesorhizobium loti, sinorhizobium meliloti) and four symbiotic regions (rhizobium et ... | 2002 | 12537565 |
| diversity of alpha-halocarboxylic acid dehalogenases in bacteria isolated from a pristine soil after enrichment and selection on the herbicide 2,2-dichloropropionic acid (dalapon). | five pure cultures of bacteria (strains da1-5) able to degrade 2,2-dichloropropionic acid (22dcpa) were isolated for the first time from pristine bulk soil samples. from 16s rdna analysis, it was concluded that strains da2, da3 and da4 were members of the bradyrhizobium subgroup (alpha-proteobacteria), strain da5 clustered in the brucella assemblage (alpha-proteobacteria) and strain da1 clustered in the beta-proteobacteria. biochemical and molecular analysis of the dehalogenases from the isolate ... | 2003 | 12542712 |
| [phylogenetic analysis of two rhizobia new groups]. | on the basis of numerical taxonomy, sds-page whole-cell protein analysis, 16s rdna pcr-rflp and dna-dna hybridization, the full length of 16srdna of two strains (xj96060, xj96408) were sequenced and compared with the 16s rdna sequences of other members of the alpha 2 subclass of the proteobacteria available from genbank. an unrooted tree was produced to determine the phylogenetic relationships of two groups. the results showed that all strains were clustered into 6 branches, they were sinorhizob ... | 2000 | 12548870 |
| [study on the improvement of plasmid stability in soybean rhizobia]. | by using luxab as the report genes, 3.2 kb parcba/de gene fragment from ptr102 was inserted into plafr3 which contained a 3.7 kb enhancing fragment and deleted its cos site. recombinant plasmids phn155 and phn156 were obtained. contrasted plasmids phn157 and phn158 which contained cos site were also constructed. these four plasmids were transferred into sinorhizobium fredii hn01 by tri-parental mating, and plasmid phn155 and phn158 were introduced into bradyrhizobium japonicum ta11 by two-parent ... | 2000 | 12548995 |
| [study on polyphasic taxonomy of rhizobia isolated from lespedeza species]. | the diversity of rhizobia isolated from lespedeza spp. was determined on the basis of numerical analysis of phenotypic characteristics, sodium dodecyl sulfate-polyacrylarmide gel electrophoresis (sds-page) of proteins, dna-dna homology and restriction fragment length polymorphism (rflp) analysis of 16s-ribosomal dna genes. according to numerical analysis of 125 phenotypic characteristics, strains were divided into two groups at a similarity level of 67%. group i included all the fast-growing str ... | 1999 | 12555566 |
| [genetic diversity among chinese peanut rhizobia by rep-pcr analysis]. | repetitive sequences(repetitive extragenic palindromic[rep], and enterobacterial repetitive intergenic consensus [eric]) with the polymerase chain reaction(pcr) were used to fingerprint pure dna extracted from 79 bradyrhizobial strains. these strains included 59 peanut rhizobia [bradyrhizobium sp. (arachis)] isolated from root nodules of 24 peanut (arachis hypogaea l) cultivars from 23 sites in 11 provinces in china, 6 peanut rhizobial strains from other nations, and 14 reference strains of othe ... | 1999 | 12555567 |
| characterization of ndvd, the third gene involved in the synthesis of cyclic beta-(1 --> 3),(1 --> 6)-d-glucans in bradyrhizobium japonicum. | previously, we identified two genes in bradyrhizobium japonicum (ndvb, ndvc) that are required for cyclic beta-(1 --> 3),(1 --> 6)-d-glucan synthesis and successful symbiotic interaction with soybean (glycine max). in this study, we report a new open reading frame (orf1) located in the intergenic region between ndvb and ndvc, which is essential for beta-glucan synthesis and effective nodulation of g. max. this new gene is designated ndvd (nodule development). the ndvd translation product has a p ... | 2002 | 12556128 |
| isolation and molecular characterization of pmg160, a mobilizable cryptic plasmid from rhodobacter blasticus. | a 3.4-kb cryptic plasmid was obtained from a new isolate of rhodobacter blasticus. this plasmid, designated pmg160, was mobilizable by the conjugative strain escherichia coli s17.1 into rhodobacter sphaeroides, rhodobacter capsulatus, and rhodopseudomonas palustris. it replicated in the latter strains but not in rhodospirillum rubrum, rhodocyclus gelatinosus, or bradyrhizobium species. plasmid pmg160 was stably maintained in r. sphaeroides for more than 100 generations in the absence of selectio ... | 2003 | 12570988 |
| phenotypic and genotypic diversity of rhizobia nodulating pterocarpus erinaceus and p. lucens in senegal. | a total of fifty root nodules isolates of fast-growing and slow growing rhizobia from pterocarpus ennaceus and pterocarpus lucens respectively native of sudanean and sahelian regions of senegal were characterized. these isolates were compared to representative strains of known rhizobial species. twenty-two new isolates were slow growers and twenty-eight were fast growers. a polyphasic approach was performed including comparative total protein sodium dodecyl sulphate polyacrylamide gel (sds-page) ... | 2002 | 12583718 |
| complete genomic sequence of nitrogen-fixing symbiotic bacterium bradyrhizobium japonicum usda110. | the complete nucleotide sequence of the genome of a symbiotic bacterium bradyrhizobium japonicum usda110 was determined. the genome of b. japonicum was a single circular chromosome 9,105,828 bp in length with an average gc content of 64.1%. no plasmid was detected. the chromosome comprises 8317 potential protein-coding genes, one set of rrna genes and 50 trna genes. fifty-two percent of the potential protein genes showed sequence similarity to genes of known function and 30% to hypothetical gene ... | 2002 | 12597275 |
| complete genomic sequence of nitrogen-fixing symbiotic bacterium bradyrhizobium japonicum usda110 (supplement). | | 2002 | 12597279 |
| rrna and nifd phylogeny of bradyrhizobium from sites across the pacific basin. | many undomesticated legumes harbor nodule bacteria related to the soybean symbiont bradyrhizobium elkanii, but little is known about their phylogenetic relationships or geographic distribution. sequences of ribosomal genes (16s rrna and partial 23s rrna) and the nitrogenase alpha-subunit gene (nifd) were analyzed in 22 isolates of this group sampled from diverse legumes in korea, japan, the usa, mexico, costa rica and panama. some strains from asia and north america shared identical sequences fo ... | 2003 | 12620615 |
| the mid genes of rhizobium sp strain tal1145 are required for degradation of mimosine into 3-hydroxy-4-pyridone and are inducible by mimosine. | mimosine is a toxin present in the tree-legume leucaena (leucaena leucocephala), including its root nodules and the root exudates. the leucaena-nodulating rhizobium sp. strain tal1145 degrades mimosine (mid(+)) and utilizes it as a source of carbon and nitrogen. twelve tal1145 mutants defective in mimosine degradation (mid(-)) were made through tn3hogus, tnphoa or kanamycin-resistance-cassette insertions. a 5.0 kb psti fragment of tal1145, subcloned from a cosmid clone containing mid genes for m ... | 2003 | 12624215 |
| dual intracellular localization and targeting of aminoimidazole ribonucleotide synthetase in cowpea. | de novo purine biosynthesis is localized to both mitochondria and plastids isolated from bradyrhizobium sp.-infected cells of cowpea (vigna unguiculata l. walp) nodules, but several of the pathway enzymes, including aminoimidazole ribonucleotide synthetase (airs [ec 6.3.3.1], encoded by vupur5), are encoded by single genes. immunolocalization confirmed the presence of airs protein in both organelles. enzymatically active airs was purified separately from nodule mitochondria and plastids. n-termi ... | 2003 | 12644656 |
| bosea eneae sp. nov., bosea massiliensis sp. nov. and bosea vestrisii sp. nov., isolated from hospital water supplies, and emendation of the genus bosea (das et al. 1996). | on the basis of phenotypic and dna relatedness data, three novel species of the genus bosea are proposed, bosea massiliensis (63287t =cip 106336t =ccug 43117t), bosea vestrisii (34635t =cip 106340t =ccug 43114t) and bosea eneae (34614t =cip 106338t =ccug 43111t). the original description of the genus bosea included thiosulphate oxidation as a phenotypic feature, when the sole and type species of the genus, bosea thiooxidans, was proposed. the three novel species described herein were not able to ... | 2003 | 12656146 |
| community structure of microbial biofilms associated with membrane-based water purification processes as revealed using a polyphasic approach. | the microbial communities of membrane biofilms occurring in two full-scale water purification processes employing microfiltration (mf) and reverse osmosis (ro) membranes were characterized using a polyphasic approach that employed bacterial cultivation, 16s rdna clone library and fluorescence in situ hybridization techniques. all methods showed that the alpha-proteobacteria was the largest microbial fraction in the samples, followed by the gamma-proteobacteria. this suggested that members of the ... | 2004 | 12682791 |
| [genetic diversity and phylogeny of rhizobia isolated from peanut (arachis hypogaea)]. | forty three rhizobium strains isolated from peanut (arachis hypogaea) and 15 reference strains from other genus and species were analyzed by the method of 16s rrna rflp, 16s rrna sequencing and 16s-23s igs pcr rflp. the results of the 16s rrna rflp shown that 43 strains tested were all ascribed to the genus of bradyrhizobium phylogenetically. strains tested were adjacent to the b. japonicum and far from b. elkanii 16s rrna genotype. the genotypes generated by the 4 restriction endonucleases, mbo ... | 2002 | 12693105 |
| characterization of a novel ser-cisser-lys catalytic triad in comparison with the classical ser-his-asp triad. | amidase signature family enzymes, which are widespread in nature, contain a newly identified ser-cisser-lys catalytic triad in which the peptide bond between ser131 and the preceding residue gly130 is in a cis configuration. in order to characterize the property of the novel triad, we have determined the structures of five mutant malonamidase e2 enzymes that contain a cys-cisser-lys, ser-cisala-lys, or ser-cisser-ala triad or a substitution of gly130 with alanine. cysteine cannot replace the rol ... | 2003 | 12711609 |
| the enigmatic mitochondrial orf ymf39 codes for atp synthase chain b. | ymf39 is a conserved hypothetical protein-coding gene found in mitochondrial genomes of land plants and certain protists. we speculated earlier, based on a weak sequence similarity between ymf39 from a green alga and the atpf gene product from bradyrhizobium, that ymf39 might code for subunit b of mitochondrial f(0)f(1)-atp synthase. to test this hypothesis, we have sequenced ymf39 from five protists with minimally derived mitochondrial genomes, the jakobids. in addition, we isolated the mitocho ... | 2003 | 12711680 |
| fur is not the global regulator of iron uptake genes in rhizobium leguminosarum. | rhizobium leguminosarum fur mutants were unaffected in fe-dependent regulation of several operons that specify different fe uptake systems, yet cloned r. leguminosarum fur partially corrected an escherichia coli fur mutant and r. leguminosarum fur protein bound to canonical fur boxes. the lack of a phenotype in fur mutants is not due to functional redundancy with irr, another member of the fur superfamily found in the rhizobia, since irr fur double mutants are also unaffected in fe-responsive re ... | 2003 | 12724397 |
| structural and functional defects caused by point mutations in the alpha-crystallin domain of a bacterial alpha-heat shock protein. | the diverse family of alpha-crystallin-type small heat shock proteins (alpha-hsps or shsps) is characterised by a central, moderately conserved alpha-crystallin domain. oligomerisation followed by dissociation of subparticles is thought to be a prerequisite for chaperone function. we demonstrate that hsph, a bacterial alpha-hsp from the soybean-symbiont bradyrhizobium japonicum, assembles into dynamic complexes freely exchanging subunits with homologous and heterologous complexes. the importance ... | 2003 | 12729765 |
| discordant phylogenies within the rrn loci of rhizobia. | it is evident from complete genome sequencing results that lateral gene transfer and recombination are essential components in the evolutionary process of bacterial genomes. since this has important implications for bacterial systematics, the primary objective of this study was to compare estimated evolutionary relationships among a representative set of alpha-proteobacteria by sequencing analysis of three loci within their rrn operons. tree topologies generated with 16s rrna gene sequences were ... | 2003 | 12730157 |
| the ftsh gene of the wine bacterium oenococcus oeni is involved in protection against environmental stress. | the wine bacterium oenococcus oeni has to cope with harsh environmental conditions, including an acidic ph, a high alcoholic content, nonoptimal growth temperatures, and growth-inhibitory compounds such as fatty acids, phenolic acids, and tannins. we describe the characterization and cloning of the o. oeni ftsh gene, encoding a protease belonging to the atp binding cassette protein superfamily. the o. oeni ftsh protein is closest in sequence similarity to the ftsh homologue of lactococcus lactis ... | 2003 | 12732516 |
| competition among bradyrhizobium strains for nodulation of green gram (vigna radiata): use of dark-nodule strain. | the competitiveness of dual-strain inoculum of bradyrhizobium strains s24 and gr4 was demonstrated for nodulation of green gram (vigna radiata). strain s24 formed pink nodules, gr4 produced visually distinguishable dark-brown nodules. when a mixture of these bradyrhizobium strains was applied as inoculum, nodules of both pink and dark-brown types were formed on the same root. the strain gr4, which was less competitive than strain s24, was mutagenized with n-methyl-n'-nitro-n-nitrosoguanidine to ... | 2003 | 12744082 |
| new nodw- or nifa-regulated bradyrhizobium japonicum genes. | a cluster of genes coding for putative plant cell-wall degrading enzymes (i.e., genes for two endoglucanases [guna and guna2], one pectinmethylesterase [pme], and one polygalacturonase [pgl]) was identified by sequence similarities in the symbiotic region of the bradyrhizobium japonicum chromosome. in addition, a systematic screen of the region revealed several genes potentially transcribed by the sigma(54)-rna polymerase and activated by the transcriptional regulator nifa (i.e., genes for prote ... | 2003 | 12744463 |
| nitrogen fixation in transposon mutants from bradyrhizobium japonicum usda 110 impaired in nitrate reductase. | tn5 transposon mutagenesis was carried out in bradyrhizobium japonicum strain usda 110 to produce defective mutants. from over one thousand clones expressing low levels of nitrate reductase activity as free-living bacteria, approximately five percent had significantly different ratios of nodulation, n2 fixation or nitrate reductase activity compared to the wild strain when determined in bacteroids from soybean nodules. tn5 insertions were checked previously and mutants were arranged into four di ... | 2003 | 12756917 |
| molecular diversity of denitrifying genes in continental margin sediments within the oxygen-deficient zone off the pacific coast of mexico. | to understand the composition and structure of denitrifying communities in the oxygen-deficient zone off the pacific coast of mexico, the molecular diversity of nir genes from sediments obtained at four stations was examined by using a pcr-based cloning approach. a total of 50 operational taxonomic units (otus) for nirk and 82 otus for nirs were obtained from all samples. forty-four of the nirs clones and 31 of the nirk clones were sequenced; the levels of similarity of the nirs clones were 52 t ... | 2003 | 12788762 |
| bradyrhizobium japonicum nnrr, a denitrification regulator, expands the fixlj-fixk2 regulatory cascade. | in bradyrhizobium japonicum, a gene named nnrr was identified which encodes a protein with high similarity to fnr/crp-type transcriptional regulators. mutant strains carrying an nnrr null mutation were unable to grow anaerobically in the presence of nitrate or nitrite, and they lacked both nitrate and nitrite reductase activities. anaerobic activation of an nnrr'-'lacz fusion required fixlj and fixk(2). in turn, n oxide-mediated induction of nir and nor genes encoding nitrite and nitric oxide re ... | 2003 | 12813094 |
| a distal arginine in oxygen-sensing heme-pas domains is essential to ligand binding, signal transduction, and structure. | to evaluate the contributions of the g(beta)-2 arginine to signal transduction in oxygen-sensing heme-pas domains, we replaced this residue with alanine in bradyrhizobium japonicum fixl and examined the results on heme-domain structure, ligand binding, and kinase regulation. in the isolated r220a bjfixl heme-pas domain, the iron-histidine bond was increased in length by 0.31 a, the heme flattened even without a ligand, and the interaction of a presumed regulatory loop (the fg loop) with the heli ... | 2003 | 12820879 |
| in most bradyrhizobium groups sequence comparison of 16s-23s rdna internal transcribed spacer regions corroborates dna-dna hybridizations. | in an extension of a previous small-scale test to assess the use of 16s-23s rdna internal transcribed spacer (its) sequences for rapid grouping of bradyrhizobia, we have sequenced the its region of 32 isolates of bradyrhizobium that had previously been studied using aflp and dna-dna hybridizations. we also included representatives of afipia and rhodopseudomonas. our results indicate that its sequences are very diverse among bradyrhizobia. nevertheless, for most of the bradyrhizobia, the grouping ... | 2003 | 12866847 |
| a novel dna-binding site for the ferric uptake regulator (fur) protein from bradyrhizobium japonicum. | the fur protein is a global regulator of iron metabolism and other processes in many bacterial species. a key feature of the model of fur function is the recognition of a dna element within target promoters with similarity to a 19-bp at-rich palindromic sequence called a fur box. the irr gene from bradyrhizobium japonicum is under the control of fur. here, we provide evidence that b. japonicum fur (bjfur) binds to the irr gene promoter with high affinity despite the absence of dna sequence simil ... | 2003 | 12881516 |
| comparative analysis of the bradyrhizobium japonicum suca region. | to study the adjustments made to the tricarboxylic acid cycle during symbiosis of nitrogen-fixing rhizobia with their host legumes, we have characterized the genes encoding the alpha-ketoglutarate dehydrogenase enzyme complex in bradyrhizobium japonicum. the genes were arranged in the order suca-sucb-scda-lpda, where scdarepresents a short-chain dehydrogenase gene (genbank accession no. ay049030). all four genes appeared to be co-transcribed, an arrangement that is so far unique to b. japonicum. ... | 2003 | 12897832 |
| identification of extracytoplasmic proteins in bradyrhizobium japonicum using phage display. | a novel gene bank of bradyrhizobium japonicum usda110spc4 was constructed using pg3dss, a phagemid vector designed for detecting genes encoding secreted proteins. in this phagemid, the phage protein iii lacks its indigenous signal peptide required for protein secretion, thus recombinant fusion proteins are displayed on the phage surface only if a functional signal peptide is provided by an inserted dna fragment. in addition, the n-terminal half of protein iii has been replaced by a short linker ... | 2003 | 12906117 |
| effect of trehalose on survival of bradyrhizobium japonicum during desiccation. | a major reason for the ineffectiveness of legume inoculants in the field is the rapid death of rhizobia because of desiccation. the major purpose of this study was to identify conditions under which alpha,alpha-trehalose would improve survival of bradyrhizobium japonicum during desiccation. | 2003 | 12911696 |
| genetic markers for analysing symbiotic relationships and lateral gene transfer in neotropical bradyrhizobia. | assays with seven sets of lineage-specific polymerase chain reaction (pcr) primers in the ribosomal rna region were performed on 96 isolates of the bradyrhizobium sp. nodule bacteria from barro colorado island, panama. the isolates were derived from 10 legume host species in six genera (centrosema, desmodium, dioclea, inga, machaerium and vigna). the pcr assays differentiated 13 composite genotypes, and sequencing of a 5' 23s rrna region indicated that all but one had a unique sequence. the most ... | 2003 | 12919482 |
| disparate oxygen responsiveness of two regulatory cascades that control expression of symbiotic genes in bradyrhizobium japonicum. | two oxygen-responsive regulatory systems controlling numerous symbiotic genes in bradyrhizobium japonicum were assayed in free-living cultures for their capacity to activate target genes under different oxygen conditions. nifa- and fixlj-controlled target genes showed disparate relative expression patterns. induction of nifa-dependent genes was observed only at oxygen concentrations below 2% in the gas phase, whereas that of fixlj-controlled targets progressively increased when the oxygen concen ... | 2003 | 12949117 |
| changing concepts in the systematics of bacterial nitrogen-fixing legume symbionts. | as of february 2003, bacteria that form nitrogen-fixing symbiotic associations with legumes have been confirmed in 44 species of 12 genera. phylogenies of these taxa containing legume symbionts based on the comparative analysis of 16s rdna sequences show that they are not clustered in one lineage but are distributed in the classes alphaproteobacteria and betaproteobacteria, and dispersed over the following nine monophyletic groups, being intermingled with other taxa that do not contain legume sy ... | 2003 | 12949698 |
| host sanctions and the legume-rhizobium mutualism. | explaining mutualistic cooperation between species remains one of the greatest problems for evolutionary biology. why do symbionts provide costly services to a host, indirectly benefiting competitors sharing the same individual host? host monitoring of symbiont performance and the imposition of sanctions on 'cheats' could stabilize mutualism. here we show that soybeans penalize rhizobia that fail to fix n(2) inside their root nodules. we prevented a normally mutualistic rhizobium strain from coo ... | 2003 | 12955144 |
| temperature-controlled structural alterations of an rna thermometer. | thermoresponsive structures in the 5'-untranslated region of mrna are known to control translation of heat shock and virulence genes. expression of many rhizobial heat shock genes is regulated by a conserved sequence element called rose for repression of heat shock gene expression. this cis-acting, untranslated mrna is thought to prevent ribosome access at low temperature through an extended secondary structure, which partially melts when the temperature rises. we show here by a series of in viv ... | 2003 | 12963744 |
| bosea minatitlanensis sp. nov., a strictly aerobic bacterium isolated from an anaerobic digester. | a strictly aerobic, mesophilic bacterium, strain amx 51(t), was isolated from anaerobic digester sludge. cells were gram-negative, motile, non-sporulating, straight to curved rods with one polar flagellum. the isolate had phenotypic traits of the genus bosea, including cellular fatty acid and substrate utilization profiles. physiological characteristics and antibiotic susceptibility were determined. phylogenetic analysis revealed that strain amx 51(t) was a member of the alpha-proteobacteria, mo ... | 2003 | 13130002 |
| effect of thorium on the growth and capsule morphology of bradyrhizobium. | the thorium effect on bradyrhizobium growth was assayed in liquid media. th4+ inhibited the growth of bradyrhizobium (chamaecytisus) bga-1, but this effect decreased in the presence of suspensions of live or dead bacterial cells. th4+ induced the formation of a gel-like precipitate when added to a dense suspension of b. (chamaecytisus) bga-1 cells. viable bradyrhizobium cells remained in suspension after precipitate formation. thorium was recovered in the precipitate, in which polysaccharide, li ... | 2003 | 14510845 |
| 2-oxoglutarate:nadp(+) oxidoreductase in azoarcus evansii: properties and function in electron transfer reactions in aromatic ring reduction. | the conversion of [(14)c]benzoyl-coenzyme a (coa) to nonaromatic products in the denitrifying beta-proteobacterium azoarcus evansii grown anaerobically on benzoate was investigated. with cell extracts and 2-oxoglutarate as the electron donor, benzoyl-coa reduction occurred at a rate of 10 to 15 nmol min(-1) mg(-1). 2-oxoglutarate could be replaced by dithionite (200% rate) and by nadph ( approximately 10% rate); in contrast nadh did not serve as an electron donor. anaerobic growth on aromatic co ... | 2003 | 14526024 |
| low sequence similarity and gene content of symbiotic clusters of bradyrhizobium sp. wm9 (lupinus) indicate early divergence of "lupin" lineage in the genus bradyrhizobium. | two sequenced nodulation regions of lupin bradyrhizobium sp. wm9 carried the majority of genes involved in the nod factor production. the nod region i harbored: nola, nodd, noda, nodb, nodc, nods, nodi, nodj, nolo, nodz, fixr, nifa, fixa, nodm, nolk and noel. this gene arrangement resembled that found in the nodulation region of bradyrhizobium japonicum usda110, however strain wm9 harbored only one nodd gene copy, while the nodm, nolk and noel genes had no counterparts in the 410 kb symbiotic re ... | 2003 | 14533715 |
| aerobic and anaerobic nitrate and nitrite reduction in free-living cells of bradyrhizobium sp. (lupinus). | induction, energy gain, effect on growth, and interaction of nitrate and nitrite reduction of bradyrhizobium sp. (lupinus) usda 3045 were characterized. both nitrate and nitrite were reduced in air, although nitrite reduction was insensitive to ammonium inhibition. anaerobic reduction of both ions was shown to be linked with energy conservation. a dissimilatory ammonification process was detected, which has not been reported in rhizobia so far. nevertheless, anaerobic conversion of nitrate to am ... | 2003 | 14553930 |
| a calcium-dependent bacterial surface protein is involved in the attachment of rhizobia to peanut roots. | as part of a project to characterize molecules involved in the crack-entry infection process leading to nodule development, a microscopic assay was used to visualize the attachment of cells of bradyrhizobium sp. strains semia 6144 and tal 1000 (labelled by introducing a plasmid expressing constitutively the green fluorescent protein gfp-s65t) to arachis hypogaea l. (peanut). qualitative and quantitative results revealed that attachment was strongly dependent on the growth phase of the bacteria. ... | 2003 | 14569294 |
| isolation and characterization of periplasmic cyclic beta-glucans of azorhizobium caulinodans. | oligoglucose molecules isolated from azorhizobium caulinodans were characterized by compositional analysis, smith degradation, matrix-assisted laser desorption/ionization time of flight mass spectrometry, and (1)h and (13)c nuclear magnetic resonance analysis. a. caulinodans produced nonbranched and unsubstituted cyclic glucans composed solely of glucose, with the degree of polymerization ranging from 10 to 13. a major fraction of the periplasmic glucans contains 11 glucose residues within rings ... | 2003 | 14592718 |
| identification and use of actinomycetes for enhanced nodulation of soybean co-inoculated with bradyrhizobium japonicum. | the utilization of actinomycetes as potential soybean (glycine max (l.)) co-inoculants was evaluated. soil samples from carbondale and belleville, ill., were used to inoculate pre-germinated soybean plants to determine antibiotic sensitivity in the native bradyrhizobium japonicum population. sensitivity was in the order kanamycin > tetracycline > oxytetracycline > rifampicin > neomycin. antagonism by five actinomycete cultures toward seven test strains of b. japonicum was also assessed. the rank ... | 2003 | 14608383 |
| acidobacteria form a coherent but highly diverse group within the bacterial domain: evidence from environmental genomics. | acidobacteria have been established as a novel phylum of bacteria that is consistently detected in many different habitats around the globe by 16s rdna-based molecular surveys. the phylogenetic diversity, ubiquity and abundance of this group, particularly in soil habitats, suggest an important ecological role and extensive metabolic versatility. however, the genetic and physiological information about acidobacteria is scarce. in order to gain insight into genome structure, evolution and diversit ... | 2003 | 14617179 |
| [survival of bradyrhizobium japonicum strain 646a introduced into soil of the soybean, common bean and maize rhizosphere]. | the number dynamics of bradyrhizobium japonicum strain 646a introduced into soil in the soybean, common bean and maize rhizosphere and its dependence on inoculum doses have been studied in greenhouse experiments. it was shown that b. japonicum number in the maize, common bean and soybean rhizosphere depends on the inoculum doses (r = 0.79-0.95). it was less than 0.1% of total saprophytic bacteria number and it had no essential effect on this plant productivity. the soybean symbiosis with nodule ... | 2003 | 14618780 |
| intrinsic bioremediability of an aromatic hydrocarbon-polluted groundwater: diversity of bacterial population and toluene monoxygenase genes. | the functional and phylogenetic biodiversity of bacterial communities in a benzene, toluene, ethylbenzene and xylene (btex)-polluted groundwater was analysed. to evaluate the feasibility of using an air sparging treatment to enhance bacterial degradative capabilities, the presence of degrading microorganisms was monitored. the amplification of gene fragments corresponding to toluene monooxygenase (tmo), catechol 1,2-dioxygenase, catechol 2,3-dioxygenase and toluene dioxygenase genes in dna extra ... | 2004 | 14624316 |
| analysis of the legume-rhizobia symbiosis in shrubs from central western spain. | this work analyses the diversity of rhizobia associated with some of the predominant shrubby legumes in central-western spain. symbiotic promiscuity and effectiveness were studied using cross-inoculation experiments with shrubby species. | 2003 | 14633012 |
| molecular and culture-based analyses of aerobic carbon monoxide oxidizer diversity. | isolates belonging to six genera not previously known to oxidize co were obtained from enrichments with aquatic and terrestrial plants. dna from these and other isolates was used in pcr assays of the gene for the large subunit of carbon monoxide dehydrogenase (coxl). coxl and putative coxl fragments were amplified from known co oxidizers (e.g., oligotropha carboxidovorans and bradyrhizobium japonicum), from novel co-oxidizing isolates (e.g., aminobacter sp. strain cox, burkholderia sp. strain lu ... | 2003 | 14660374 |
| the bradyrhizobium japonicum napedabc genes encoding the periplasmic nitrate reductase are essential for nitrate respiration. | the napedabc gene cluster that encodes the periplasmic nitrate reductase from bradyrhizobium japonicum usda110 has been isolated and characterized. napa encodes the catalytic subunit, and the napb and napc gene products are predicted to be a soluble dihaem c and a membrane-anchored tetrahaem c-type cytochrome, respectively. nape encodes a transmembrane protein of unknown function, and the napd gene product is a soluble protein which is assumed to play a role in the maturation of napa. western bl ... | 2003 | 14663073 |
| pathways for phosphatidylcholine biosynthesis in bacteria. | phosphatidylcholine (pc) is the major membrane-forming phospholipid in eukaryotes with important structural and signalling functions. although many prokaryotes lack pc, it can be found in significant amounts in membranes of rather diverse bacteria. two pathways for pc biosynthesis are known in bacteria, the methylation pathway and the phosphatidylcholine synthase (pcs) pathway. in the methylation pathway, phosphatidylethanolamine is methylated three times to yield pc, in reactions catalysed by o ... | 2003 | 14663079 |
| quorum sensing in nitrogen-fixing rhizobia. | members of the rhizobia are distinguished for their ability to establish a nitrogen-fixing symbiosis with leguminous plants. while many details of this relationship remain a mystery, much effort has gone into elucidating the mechanisms governing bacterium-host recognition and the events leading to symbiosis. several signal molecules, including plant-produced flavonoids and bacterially produced nodulation factors and exopolysaccharides, are known to function in the molecular conversation between ... | 2003 | 14665677 |
| the variable part of the dnak gene as an alternative marker for phylogenetic studies of rhizobia and related alpha proteobacteria. | dnak is the 70 kda chaperone that prevents protein aggregation and supports the refolding of damaged proteins. due to sequence conservation and its ubiquity this chaperone has been widely used in phylogenetic studies. in this study, we applied the less conserved part that encodes the so-called alpha-subdomain of the substrate-binding domain of dnak for phylogenetic analysis of rhizobia and related non-symbiotic alpha-proteobacteria. a single 330 bp dna fragment was routinely amplified from dna t ... | 2003 | 14666974 |
| genetic diversity of bradyrhizobial populations from diverse geographic origins that nodulate lupinus spp. and ornithopus spp. | the genetic diversity of 45 bradyrhizobial isolates that nodulate several lupinus and ornithopus species in different geographic locations was investigated by 16s rdna pcr-rflp and sequence analysis, 16s-23s rdna intergenic spacer (igs) pcr-rflp analysis, and eric-pcr genomic fingerprinting. reference strains of bradyrhizobium japonicum, b. liaoningense and b. elkanii and some canarian isolates from endemic woody legumes in the tribe genisteae were also included. the 16s rdna-rflp analysis resol ... | 2003 | 14666990 |
| a motility revertant of the ndvb mutant of bradyrhizobium japonicum. | a motility revertant of a bradyrhizobium japonicum ndvb mutant was isolated and characterized. the ndvb mutants of b. japonicum have been reported to be osmotically sensitive, as well as defective in motility, periplasmic cyclic beta-(1-->3), (1-->6)-d-glucan synthesis, and symbiosis with soybean. the motility revertant was restored for osmotic tolerance but not for cyclic beta-glucan production or effective symbiosis. these results support our hypothesis that cyclic beta-glucans have an importa ... | 2003 | 14669923 |
| identification of fast and slow growing rhizobia nodulating soybean (glycine max [l.] merr) by a multiplex pcr reaction. | two dna fragments, a 730-bp and a 900-bp fragment, one homologous to host cultivar specificity genes nolbt of sinorhizobium fredii and the other one homologous to rsalpha, an insertion-like sequence present in bradyrhizobium japonicum, were generated by polymerase chain reaction (pcr) with two pairs of primers. the amount of each fragment generated by the multiplex pcr was proportional to the amount of template dna present. the amplification of the 900-bp rsalpha fragment was more sensitive, sin ... | 2003 | 14680692 |
| an evolutionary hot spot: the pngr234b replicon of rhizobium sp. strain ngr234. | rhizobium sp. strain ngr234 has an exceptionally broad host range and is able to nodulate more than 112 genera of legumes. since the overall organization of the ngr234 genome is strikingly similar to that of the narrow-host-range symbiont rhizobium meliloti strain 1021 (also known as sinorhizobium meliloti), the obvious question is why are the spectra of hosts so different? study of the early symbiotic genes of both bacteria (carried by the syma plasmids) did not provide obvious answers. yet, bo ... | 2004 | 14702322 |
| characterization of lps mutants of peanut specific bradyrhizobium (gn17). | two mutants of bradyrhizobium sp. (arachis) strain gn17 having altered lipopolysaccharide (lps) composition were isolated upon random tn5 mutagenesis to study their binding with peanut root lectin (pra ii). these mutant strains designated as gn17m1 and gn17m2 produced rough colonies and showed autoagglutination. flow cytometric analyses indicated that strain gn17m1 bind to pra ii with highest efficiency. both the mutants synthesized only high molecular weight lipopolysaccharides as observed by s ... | 2002 | 14707486 |
| bradyrhizobium elkanii rtxc gene is required for expression of symbiotic phenotypes in the final step of rhizobitoxine biosynthesis. | we disrupted the rtxc gene on the chromosome of bradyrhizobium elkanii usda94 by insertion of a nonpolar aph cartridge. the rtxc mutant, designated deltartxc, produced serinol and dihydrorhizobitoxine but no rhizobitoxine, both in culture and in planta. the introduction of cosmids harboring the rtxc gene into the deltartxc mutant complemented rhizobitoxine production, suggesting that rtxc is involved in the final step of rhizobitoxine biosynthesis in b. elkanii usda94. glycine max cv. lee inocul ... | 2004 | 14711685 |
| accumulating behaviour of lupinus albus l. growing in a normal and a decalcified calcic luvisol polluted with zn. | lupinus albus l. is a leguminous plant that is starting to generate interest for the phytoremediation soils showing intermediate metal pollution. among these metals, zn causes major phytotoxicity problems and is common in polluted soils of central spain. the purpose of this study was to explore the nutritional behaviour of this plant species towards increasing zn concentrations in two calcic luvisol soils: a normal basic soil and a decalcified acid soil. for this purpose the effects of different ... | 2003 | 14717438 |
| two distinct crt gene clusters for two different functional classes of carotenoid in bradyrhizobium. | aerobic photosynthetic bacteria possess the unusual characteristic of producing different classes of carotenoids. in this study, we demonstrate the presence of two distinct crt gene clusters involved in the synthesis of spirilloxanthin and canthaxanthin in a bradyrhizobium strain. each cluster contains the genes crte, crtb, and crti leading to the common precursor lycopene. we show that spirilloxanthin is associated with the photosynthetic complexes, while canthaxanthin protects the bacteria fro ... | 2004 | 14734565 |
| rare bacterium of new genus isolated with prolonged enrichment culture. | dynamic change in microbial flora was monitored with an oxygen electrode. the 1st phase microorganisms, which first grew well in lb medium, were followed by the 2nd phase microorganisms, which supposedly assimilated microbial cells of the 1st phase and their metabolites. in a similar way, a change in microbial flora was observed from the 1st phase to the 4th phase in 84 hr. based on this observation, prolonged enrichment culture was done for as long as two months to increase the ratio of existen ... | 2004 | 14745160 |
| cloning, purification, crystallization and preliminary crystallographic studies of bradyrhizobium fucosyltransferase nodz. | the alpha-1,6-fucosyltransferase nodz from bradyrhizobium sp. wm9 (lupinus), composed of 325 amino acids with a molecular weight of 37 kda, has been cloned, expressed and purified. protein crystals suitable for x-ray diffraction were obtained under optimized crystallization conditions using ammonium dihydrogen phosphate as a precipitant. the crystals are hexagonal and belong to space group p6(1)22 or p6(5)22, with unit-cell parameters a = 125.5, c = 95.6 a, and contain 56.8% solvent and a single ... | 2004 | 14747720 |
| microbial characterization during the early habitation of the international space station. | an evaluation of the microbiota from air, water, and surface samples provided a baseline of microbial characterization onboard the international space station (iss) to gain insight into bacterial and fungal contamination during the initial stages of construction and habitation. using 16s genetic sequencing and rep-pcr, 63 bacterial strains were isolated for identification and fingerprinted for microbial tracking. of the bacterial strains that were isolated and fingerprinted, 19 displayed similar ... | 2004 | 14749908 |
| a dominant-negative fur mutation in bradyrhizobium japonicum. | in many bacteria, the ferric uptake regulator (fur) protein plays a central role in the regulation of iron uptake genes. because iron figures prominently in the agriculturally important symbiosis between soybean and its nitrogen-fixing endosymbiont bradyrhizobium japonicum, we wanted to assess the role of fur in the interaction. we identified a fur mutant by selecting for manganese resistance. manganese interacts with the fur protein and represses iron uptake genes. in the presence of high level ... | 2004 | 14973020 |
| use of the multipurpose transposon tn kpk2 for the mutational analysis of chromosomal regions upstream and downstream of the sipf gene in bradyrhizobium japonicum. | the dna regions upstream and downstream of the bradyrhizobium japonicum gene sipf were cloned by in vivo techniques and subsequently sequenced. in order to study the function of the predicted genes, a new transposon for in vitro mutagenesis, tn kpk2, was constructed. this mutagenesis system has a number of advantages over other transposons. tn kpk2 itself has no transposase gene, making transposition events stable. extremely short inverted repeats minimize the length of the transposable element ... | 2004 | 14986109 |
| insights into signal transduction involving pas domain oxygen-sensing heme proteins from the x-ray crystal structure of escherichia coli dos heme domain (ec dosh). | the x-ray crystal structure of the escherichia coli (ec) direct oxygen sensor heme domain (ec dosh) has been solved to 1.8 a using fe multiple-wavelength anomalous dispersion (mad), and the positions of met95 have been confirmed by selenomethionine ((se)met) mad. ec dosh is the sensing part of a larger two-domain sensing/signaling protein, in which the signaling domain has phosphodiesterase activity. the asymmetric unit of the crystal lattice contains a dimer comprised of two differently ligated ... | 2004 | 15005609 |
| polymerase chain reaction denaturing gradient gel electrophoresis analysis of the n2-fixing bacterial diversity in soil under acacia tortilis ssp. raddiana and balanites aegyptiaca in the dryland part of senegal. | denaturing gradient gel electrophoresis (dgge) of amplified nifh gene fragments was used to study the diazotrophic community of soil samples under acacia tortilis ssp. raddiana (legume tree) and balanites aegyptiaca (non-legume tree), two dominant plant species growing naturally in the dryland part of senegal. samples were taken along transects from the stem up to 10 m distance from it, at depths of 0-0.25 m and 0.25-0.50 m. sampling was done in the dry season (25 june 1999) and in the rainy sea ... | 2004 | 15008817 |
| phylogenetic analyses of symbiotic nodulation genes support vertical and lateral gene co-transfer within the bradyrhizobium genus. | symbiotic nitrogen fixing bacteria-known as rhizobia-harbour a set of nodulation (nod) genes that control the synthesis of modified lipo-chitooligosaccharides, called nod factors that are required for legume nodulation. the noda gene, which is essential for symbiosis, is responsible for the attachment of the fatty acid group to the oligosaccharide backbone. the nodz, noll, and noei genes are involved in specific modifications of nod factors common to bradyrhizobia, i.e., the transfer of a fucosy ... | 2004 | 15012950 |
| soybean (glycine max. l.) and bacteroid glyoxylate cycle activities during nodular senescence. | soybean (glycine max. l.) nodular senescence results in the dismantling of the peribacteroid membrane (pbm) and in an increase of soybean isocitrate lyase (icl; ec 4.1.3.1) and malate synthase (ms; ec 4.1.3.2) mrna and protein levels. this suggests that in senescing soybean nodular cells, the specific glyoxylate cycle enzyme activities might be induced to reallocate carbon obtained from the pbm degradation. in order to evaluate as well the carbon metabolism of the nitrogen-fixing bradyrhizobium ... | 2004 | 15022832 |
| molecular characterization of nosrzdfylx genes coding for denitrifying nitrous oxide reductase of bradyrhizobium japonicum. | the nosrzdfylx gene cluster for the respiratory nitrous oxide reductase from bradyrhizobium japonicum strain usda110 has been cloned and sequenced. seven protein coding regions corresponding to nosr, nosz, the structural gene, nosd, nosf, nosy, nosl, and nosx were detected. the deduced amino acid sequence exhibited a high degree of similarity to other nitrous oxide reductases from various sources. the nosz protein included a signal peptide for protein export. mutant strains carrying either a nos ... | 2004 | 15028871 |
| phenotypic and genotypic analysis of rhizobia isolated from pasture legumes native of sardinia and asinara island. | thirty-five rhizobial strains were isolated from nodules of lotus edulis, l. ornithopodioides, l. cytisoides, hedysarum coronarium, ornithopus compressus and scorpiurus muricatus growing in sardinia and asinara island. basic characteristics applied to identification of rhizobia such as symbiotic properties, antibiotic- and salt-resistance, temperate-sensitivities, utilization of different sources of carbon and nitrogen were studied. the results from the 74 metabolic tests were used for cluster a ... | 2004 | 15031655 |
| expression of nir, nor and nos denitrification genes from bradyrhizobium japonicum in soybean root nodules. | expression of bradyrhizobium japonicum wild-type strain usda110 nirk, norc and nosz denitrification genes in soybean root nodules was studied by in situ histochemical detection of beta-galactosidase activity. similarly, p(nirk)-lacz, p(norc)-lacz, and p(nosz)-lacz fusions were also expressed in bacteroids isolated from root nodules. levels of beta-galactosidase activity were similar in both bacteroids and nodule sections from plants that were solely n(2)-dependent or grown in the presence of 4 m ... | 2004 | 15032854 |
| a novel symbiotic nitrogen-fixing member of the ochrobactrum clade isolated from root nodules of acacia mangium. | ten strains of root nodule bacteria were isolated from the nodules of acacia mangium grown in the philippines and thailand. partial sequences (approx. 300 bp) of the 16s rrna gene of each isolate were analyzed. the nucleotide sequences of strain dasa 35030 indicated high homology (>99%) with members of the genus ochrobactrum in brucellaceae, although the sequences of other isolates were homologous to those of two distinct genera bradyrhizobium and rhizobium. the strain dasa 35030 was strongly su ... | 2004 | 15057707 |
| root nodule bradyrhizobium spp. harbor tfdaalpha and cada, homologous with genes encoding 2,4-dichlorophenoxyacetic acid-degrading proteins. | the distribution of tfdaalpha and cada, genes encoding 2,4-dichlorophenoxyacetate (2,4-d)-degrading proteins which are characteristic of the 2,4-d-degrading bradyrhizobium sp. isolated from pristine environments, was examined by pcr and southern hybridization in several bradyrhizobium strains including type strains of bradyrhizobium japonicum usda110 and bradyrhizobium elkanii usda94, in phylogenetically closely related agromonas oligotrophica and rhodopseudomonas palustris, and in 2,4-d-degradi ... | 2004 | 15066803 |
| [influence of supplement of agricultural useful strains of microorganisms on microbial coenobia of plant rhizosphere]. | it was revealed in the fields experiments that the treatment of seeds by microbial preparations (nitrogen fixing, phosphorus mobilizing bacteria and antagonists of phythopatogenic micromycetes) leads to the decrease of quantity of micromycetes and oligotrophoic bacteria in the rhizosphere soil. | 2003 | 15077548 |
| chlorobenzoate-degrading bacteria in similar pristine soils exhibit different community structures and population dynamics in response to anthropogenic 2-, 3-, and 4-chlorobenzoate levels. | a study was conducted to determine the diversity of 2-, 3-, and 4-chlorobenzoate (cb) degraders in two pristine soils with similar physical and chemical characteristics. surface soils were collected from forested sites and amended with 500 microg of 2-, 3-, or 4-cb g(-1) soil. the cb levels and degrader numbers were monitored throughout the study. degraders were isolated, grouped by dna fingerprints, identified via 16s rdna sequences, and screened for plasmids. the cb genes in selected degraders ... | 2004 | 15085300 |
| casuarina cunninghamiana tissue extracts stimulate the growth of frankia and differentially alter the growth of other soil microorganisms. | aqueous extracts of host plant casuarina cunninghamiana tissue altered the in vitro growth of its diazotrophic microsymbiont frankia and a selection of other soil microorganisms. the growth of actinomycetous frankia strains, 55005. avci1, cesi5, cji82 001, and cj was stimulated by aqueous extracts of c. cunninghamiana tissue. green cladodes (photosynthetic branches), unsuberized roots, and suberized roots were more stimulatory than dry cladodes and seed tissue. aqueous extracts of green cladodes ... | 2004 | 15112734 |
| new method of denitrification analysis of bradyrhizobium field isolates by gas chromatographic determination of (15)n-labeled n(2). | to evaluate the denitrification abilities of many bradyrhizobium field isolates, we developed a new (15)n-labeled n(2) detection methodology, which is free from interference from atmospheric n(2) contamination. (30)n(2) ((15)n(15)n) and (29)n(2) ((15)n(14)n) were detected as an apparent peak by a gas chromatograph equipped with a thermal conductivity detector with n(2) gas having natural abundance of (15)n (0.366 atom%) as a carrier gas. the detection limit was 0.04% (30)n(2), and the linearity ... | 2004 | 15128547 |
| genome-wide comparison of the his-to-asp phosphorelay signaling components of three symbiotic genera of rhizobia. | histidine-to-aspartate (his-asp) phosphorelay (or two-component) systems are very common signal transduction mechanisms that are implicated in a wide variety of cellular responses to environmental stimuli. the his-asp phosphorelay components include "sensor histidine kinase (hk)", "phosphotransfer intermediate (hpt)", and "response regulator (rr)". with special reference to three bacterial species (mesorhizobium loti, bradyrhizobium japonicum, sinorhizobium meliloti), each of which belongs to a ... | 2004 | 15141946 |
| the ferric uptake regulator (fur) protein from bradyrhizobium japonicum is an iron-responsive transcriptional repressor in vitro. | the fur protein represses transcription of iron-responsive genes in bacteria. the discovery that fur is a zinc metalloprotein and the use of surrogate metals for fe(2+) for in vitro studies question whether fur is a direct iron sensor. in the present study, we show that the affinity of fur from bradyrhizobium japonicum (bjfur) for its target dna increases 30-fold in the presence of metal, with a k(d) value of about 2 nm. dnase i footprinting experiments showed that bjfur protected its binding si ... | 2004 | 15148310 |
| reduction of dark chilling stress in n-fixing soybean by nitrate as indicated by chlorophyll a fluorescence kinetics. | sub-optimal night temperatures below 15 degrees c (dark chilling) frequently reduce soybean [glycine max (l.) merrill] production. nitrate application is known to alleviate some of the negative effects of low root zone temperatures, probably by counteracting the inhibition caused by decreased symbiotic nitrogen fixation (snf). under field conditions, however, dark chilling is frequently not accompanied by low root zone temperatures. the possibility that nitrate might increase dark-chilling toler ... | 2004 | 15153191 |
| bacteriophytochrome and regulation of the synthesis of the photosynthetic apparatus in rhodopseudomonas palustris: pitfalls of using laboratory strains. | the synthesis of the photosynthetic apparatus of different strains of rhodopseudomonas palustris has been studied as a function of the oxygen concentration and far-red light. for strain cea001, only a small amount of photosynthetic apparatus is synthesized in the dark for oxygen concentration higher than 8% whereas synthesis is strongly enhanced by far-red light illumination. this enhancement is due to the action of a bacteriophytochrome (orf2127/orf2128), which antagonizes the repressor ppsr. o ... | 2004 | 15170489 |
| coprecipitation of th(4+) and the purified extracellular polysaccharide produced by bacterium bradyrhizobium (chamaecytisus) bga-1. | the soil bacterium bradyrhizobium (chamaecytisus) strain bga-1 produces an extracellular polymeric substance (eps) that, in the presence of fe(3+), al(3+) or th(4+) solutions, forms a gel-like precipitate composed of polysaccharide, protein, lipopolysaccharide and the metal. precipitation of the main component of the eps, the extracellular polysaccharide, and thorium was studied. the precipitate was stable, but redissolved at ph values below 3.0 or in the presence of 10 mm edta. in the precipita ... | 2004 | 15185039 |