Publications

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
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
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
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
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
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
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
[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
regulation of expression of symbiotic genes in rhizobium sp. ngr234.	research in the field of rhizobium-legume symbiosis faces a new challenge: integrate the wealth of information generated by genomic projects. the goal: apprehend the complexity of the molecular mechanisms involved in symbiotic associations. at the time of writing, the genomes of three micro-symbionts (bradyrhizobium japonicum, mesorhizobium loti and sinorhizobium meliloti) have been sequenced, and two more (those of rhizobium leguminosarum and rhizobium etli) will be completed in the near future ...	2003	15242276
effects of biotic and abiotic constraints on the symbiosis between rhizobia and the tropical leguminous trees acacia and prosopis.	n2-fixing, drought tolerant and multipurpose acacia and prosopis species are appropriate trees for reforestation of degraded areas in arid and semiarid regions of the tropics and subtropics. acacia and prosopis trees form n2-fixing nodules with a wide range of rhizobia, for example african acacias mainly with sinorhizobium sp. and mesorhizobium sp., and australian acacias with bradyrhizobium sp. although dry and hot seasons restrict formation of n2-fixing nodules on acacia and prosopis spp., ful ...	2003	15242281
quantitative and time-course evaluation of nodulation competitiveness of rhizobitoxine-producing bradyrhizobium elkanii.	abstract regression analysis of results from a mathematical competition model showed that rhizobitoxine production by bradyrhizobium elkanii usda94 gave this strain a nodulation competitiveness about 10 times greater than that of a non-rhizobitoxine-producing mutant strain on macroptilium atropurpureum (siratro). rhizobitoxine enhancement of competitive nodulation occurred at a late stage in the time-course of nodulation. all other known rhizobial factors that affect nodulation competitiveness a ...	2003	19719626
phylogeny and distribution of extra-slow-growing bradyrhizobium japonicum harboring high copy numbers of rsalpha, rsbeta and is1631.	we previously reported that extra-slow-growing bradyrhizobium japonicum isolates obtained from three field sites in japan, designated as hrs (highly reiterated sequence-possessing) strains, have high copy numbers of the insertion sequences rsalpha and rsbeta. when strain collections in the usa, japan, korea, thailand and china were examined by southern hybridization using rsalpha, rsbeta and is1631 as probes, hrs strains were found in the japanese, chinese, and american collections, but not in t ...	2003	19719636
molecular dissection of diheme cytochrome c gene from soil isolate of a gram negative, facultative chemolithotrophic sulfur oxidizer.	a gram negative chemolithotrophic bacterium (rpi) with facultative mode of nutrition was isolated from the soil. enzymological studies confirmed presence of thiosulphate oxidase, sulphite oxidase and rhodanese, all of which play role in sulfur metabolism pathway. a set of degenerate oligonucleotide primer pairs was used for thermal amplification of a major part of the coding region of the cytochrome c gene locus of this bacterium. nucleotide and translated amino acid sequence revealed the gene t ...	2004	17240791
the nitrogen-fixing gene (nifh) of rhodopseudomonas palustris: a case of lateral gene transfer?	nitrogen fixation is catalysed by some photosynthetic bacteria. this paper presents a phylogenetic comparison of a nitrogen fixation gene (nifh) with the aim of elucidating the processes underlying the evolutionary history of rhodopseudomonas palustris. in the nifh phylogeny, strains of rps. palustris were placed in close association with rhodobacter spp. and other phototrophic purple non-sulfur bacteria belonging to the alpha-proteobacteria, separated from its close relatives bradyrhizobium jap ...	2004	15256566
bradyrhizobium betae sp. nov., isolated from roots of beta vulgaris affected by tumour-like deformations.	some varieties of sugar beet, beta vulgaris, cultivated in northern spain have large deformations that resemble the tumours produced by agrobacterium species. in an attempt to isolate the agent responsible for these deformations, several endophytic slow-growing bacterial strains were isolated, the macroscopic morphology of which resembled that of bradyrhizobium species. these strains were not able to produce tumours in nicotiana tabacum plants and, based on phylogenetic analysis of their 16s rrn ...	2004	15280302
indole-3-acetic acid biosynthesis is deficient in gluconacetobacter diazotrophicus strains with mutations in cytochrome c biogenesis genes.	gluconacetobacter diazotrophicus is an endophyte of sugarcane frequently found in plants grown in agricultural areas where nitrogen fertilizer input is low. recent results from this laboratory, using mutant strains of g. diazotrophicus unable to fix nitrogen, suggested that there are two beneficial effects of g. diazotrophicus on sugarcane growth: one dependent and one not dependent on nitrogen fixation. a plant growth-promoting substance, such as indole-3-acetic acid (iaa), known to be produced ...	2004	15292139
light and redox control of photosynthesis gene expression in bradyrhizobium: dual roles of two ppsr.	the two closely related bacteria bradyrhizobium and rhodopseudomonas palustris show an unusual mechanism of regulation of photosystem formation by light thanks to a bacteriophytochrome that antirepresses the regulator ppsr. in these two bacteria, we found out, unexpectedly, that two ppsr genes are present. we show that the two bradyrhizobium ppsr proteins exert antagonistic effects in the regulation of photosystem formation with a classical repressor role for ppsr2 and an unexpected activator ro ...	2004	15304477
[the chemotactic properties of bradyrhizobium japonicum in the presence of natural fine-grained minerals].	the natural argillaceous minerals montmorillonite and palygorskite were found to enhance the motility of bradyrhizobium japonicum cells and to slow down their chemotactic motion to glucose. the latter effect of the minerals is probably due to the adsorption of mineral particles on the cell surface and the blockade of the receptors that are responsible for the chemotactic behavior of the bacterium.	2004	15315230
biosynthesis of artificial microperoxidases by exploiting the secretion and cytochrome c maturation apparatuses of escherichia coli.	microperoxidases were initially isolated as peptide fragments containing covalently bound heme and are derived from naturally occurring c-type cytochromes. they are not only used as model compounds but also have potential applications as biosensors, electron carriers, photoreceptors, microzymes, and drugs. in a systematic attempt to define the minimal requirements for covalent attachment of hemes to c-type cytochromes, we have succeeded to produce artificial microperoxidases with peptide sequenc ...	2004	15328415
the promoters of two isoflavone synthase genes respond differentially to nodulation and defense signals in transgenic soybean roots.	isoflavonoids are a group of secondary metabolites common to leguminous plants that play roles in nodulation and defense responses. isoflavone synthase (ifs) catalyzes the key entry point step of isoflavone biosynthesis from the general phenylpropanoid pathway. we have cloned the 5' upstream regions of the genes encoding the two isoflavone synthase isoforms from soybean. we characterized the tissue-specific expression patterns of ifs1 and ifs2 genes of soybean by quantitative rt-pcr. isoflavone ...	2004	15356384
analysis of the root nodule-enhanced transcriptome in soybean.	for high throughput screening of root nodule-enhanced genes, cdna libraries specific for three different developmental stages of soybean root nodules were constructed after inoculation with bradyrhizobium japonicum usda110. 5,469 cdna clones were sequenced and grouped into 2,511 non-redundant (nr) ests consisting of 769 contigs and 1,742 singletons. using similarity searches against several public databases we constructed a functional classification of the ests into root nodule-specific nodulin ...	2004	15359124
perception of bradyrhizobium japonicum nod factor by soybean [glycine max (l.) merr.] root hairs under abiotic stress conditions.	suboptimal growth conditions, such as low rhizosphere temperature, high salinity, and low ph can negatively affect the rhizobia-legume symbioses, resulting in poor nodulation and lower amounts of nitrogen fixed. early stages of the bradyrhizobium japonicum-soybean [glycine max (l.) merr.] symbiosis, such as excretion of genistein (the plant-to-bacteria signal) and infection initiation can be inhibited by abiotic stresses; however, the effect on early events modulated by nod factors (bacteria-to- ...	2004	15361528
can mushrooms fix atmospheric nitrogen?	it is generally reported that fungi like pleurotus spp. can fix nitrogen (n2). the way they do it is still not clear. the present study hypothesized that only associations of fungi and diazotrophs can fix n2. this was tested in vitro. pleurotus ostreatus was inoculated with a bradyrhizobial strain nodulating soybean and p. ostreatus with no inoculation was maintained as a control. at maximum mycelial colonization by the bradyrhizobial strain and biofilm formation, the cultures were subjected to ...	2004	15381850
bacteroid proline catabolism affects n(2) fixation rate of drought-stressed soybeans.	in prior work, we observed that soybean (glycine max l. cv merr.) seeds inoculated with a mutant bradyrhizobium japonicum strain unable to catabolize pro (pro dehydrogenase(-) [prodh(-)]) resulted in plants that, when forced to depend on n(2) fixation as the sole source of nitrogen and subjected to mild drought stress, suffered twice as large a loss in seed yield as did plants inoculated with the parental strain. here, we used a continuous gas flow system to measure h(2) evolution as a function ...	2004	15448193
[effect of aboriginal populations of soy nodule bacteria on symbiotic activity of introduced strain bradyrhizobium japonicum 634b].	the method of limit dilutions was used to determine the number of soy nodule bacteria in soils of different regions of ukraine. symbiotic properties of aboriginal populations of soy rhizobia have been studied under the conditions of vegetation researches, their effect on activity of the introduced strain b. japonicum 634b has been shown. numerous aboriginal populations of soy nodule bacteria (200-3500 units per 1 g of soil) have been found in soils of fields where soy was sown during a long peri ...	2004	15456214
effect of soil bradyrhizobia on the success of soybean inoculant strain cb 1809.	four decades of soybean [glycine max (l.) merr.] cultivation in south africa has resulted in the establishment of populations of bradyrhizobia against which the recently introduced inoculant strain cb 1809 must compete. serological and dna fingerprinting methods were used to study the diversity of nodule isolates from soils at bergville, koedoeskop and morgenzon. dominant serogroups included bradyrhizobium elkanii serotype 76 at bergville (67%), bradyrhizobium japonicum serotype 123 at morgenzon ...	2004	15462522
functional expression of sinorhizobium meliloti bets, a high-affinity betaine transporter, in bradyrhizobium japonicum usda110.	among the rhizobiaceae, bradyrhizobium japonicum strain usda110 appears to be extremely salt sensitive, and the presence of glycine betaine cannot restore its growth in medium with an increased osmolarity (e. boncompagni, m. osteras, m. c. poggi, and d. le rudulier, appl. environ. microbiol. 65:2072-2077, 1999). in order to improve the salt tolerance of b. japonicum, cells were transformed with the bets gene of sinorhizobium meliloti. this gene encodes a major glycine betaine/proline betaine tra ...	2004	15466533
unexpectedly diverse mesorhizobium strains and rhizobium leguminosarum nodulate native legume genera of new zealand, while introduced legume weeds are nodulated by bradyrhizobium species.	the new zealand native legume flora are represented by four genera, sophora, carmichaelia, clianthus, and montigena. the adventive flora of new zealand contains several legume species introduced in the 19th century and now established as serious invasive weeds. until now, nothing has been reported on the identification of the associated rhizobia of native or introduced legumes in new zealand. the success of the introduced species may be due, at least in part, to the nature of their rhizobial sym ...	2004	15466541
heterologous complementation of the exopolysaccharide synthesis and carbon utilization phenotypes of sinorhizobium meliloti rm1021 polyhydroxyalkanoate synthesis mutants.	a reduced exopolysaccharide phenotype is associated with inability to synthesize polyhydroxyalkanaote (pha) stores in sinorhizobium meliloti strain rm1021. loss of function mutations in phbb and phbc result in non-mucoid colony morphology on yeast mannitol agar, compared to the mucoid phenotype exhibited by the parental strain. this phenotype is attributed to reduction in succinoglycan synthesis. we have used complementation of this phenotype and the previously described d-3-hydroxybutyrate/acet ...	2004	15476977
quantification of denitrifying bacteria in soils by nirk gene targeted real-time pcr.	denitrification, the reduction of nitrate to nitrous oxide or dinitrogen, is the major biological mechanism by which fixed nitrogen returns to the atmosphere from soil and water. microorganisms capable of denitrification are widely distributed in the environment but little is known about their abundance since quantification is performed using fastidious and time-consuming mpn-based approaches. we used real-time pcr to quantify the denitrifying nitrite reductase gene (nirk), a key enzyme of the d ...	2004	15488276
why are most rhizobia beneficial to their plant hosts, rather than parasitic?	multiple strains per plant and root-to-root (not seed-borne) transmission should favor rhizobia that invest in their own reproduction, rather than symbiotic n2 fixation, as analogous factors may favor pathogen virulence. but legumes can select for greater mutualism, controlling nodule o2 supply and reducing reproduction of rhizobia that fix less n2.	2004	15488744
metabolic and genomic diversity of rhizobia isolated from field standing native and exotic woody legumes in southern ethiopia.	eighty-seven rhizobial strains isolated from root nodules of field standing native and exotic woody legumes in southern ethiopia were characterized using the biolog method and aflp fingerprinting technique. cluster analysis of the metabolic and genomic fingerprints revealed 18 and 25 groups, respectively, demonstrating considerable diversity in rhizobial population indigenous to ethiopian soils. while 25 strains (29%) were linked to members of agrobacterium, bradyrhizobium, mesorhizobium, rhizob ...	2004	15490562
a novel genetic locus outside the symbiotic island is required for effective symbiosis of bradyrhizobium japonicum with soybean glycine max.	in order to investigate the symbiotic interaction between soybean and bradyrhizobium japonicum, tnphoa mutagenesis of the microsymbiont was performed. mutant strain 2-10 was found to induce a strongly reduced number of ineffective nodules. ultrastructural analysis of the soybean nodule central tissue revealed the presence of numerous starch granules and vacuoles in the infected cells. in addition, the number of symbiosomes was extremely low, indicating an impaired interaction between the plant a ...	2004	15501655
tetra: a web-service and a stand-alone program for the analysis and comparison of tetranucleotide usage patterns in dna sequences.	in the emerging field of environmental genomics, direct cloning and sequencing of genomic fragments from complex microbial communities has proven to be a valuable source of new enzymes, expanding the knowledge of basic biological processes. the central problem of this so called metagenome-approach is that the cloned fragments often lack suitable phylogenetic marker genes, rendering the identification of clones that are likely to originate from the same genome difficult or impossible. in such cas ...	2004	15507136
katg is the primary detoxifier of hydrogen peroxide produced by aerobic metabolism in bradyrhizobium japonicum.	bacteria are exposed to reactive oxygen species from the environment and from those generated by aerobic metabolism. catalases are heme proteins that detoxify h(2)o(2), and many bacteria contain more than one catalase enzyme. also, the nonheme peroxidase alkyl hydroperoxide reductase (ahp) is the major scavenger of endogenous h(2)o(2) in escherichia coli. here, we show that aerobically grown bradyrhizobium japonicum cells express a single catalase activity. four genes encoding putative catalases ...	2004	15547258
[the significance of exometabolites in the formation and operation of the soybean-rhizobium symbiosis].	the effect of various inoculates of the soybean-specific strain of nodule bacteria bradyrhizobium japonicum 634b (unwashed cells, cells washed from the exopolysaccharide-protein complex, and cells combined with the complex) on the formation and operation of soybean-rhizobium symbiosis. it was shown that addition of the exopolysaccharide-protein complex doubled the ability of the microsymbiont to form nodules, nodule weight, and the nitrogenase activity of the nodules. bradyrhizobium japonicum 63 ...	2004	15553789
phenotypic and genomic characteristics of rhizobia isolated from genista tinctoria root nodules.	forty three rhizobial strains isolated from root nodules of genista tinctoria growing in england, ukraine, and poland were compared with 21 representatives of the recognized rhizobial species and two unclassified bradyrhizobium sp. (lupinus) strains by performing a numerical analysis of 102 phenotypic features and with the reference bradyrhizobia by simplified aflp analysis with one restriction enzyme psti and one selective primer psti-a. all genista tinctoria microsymbionts were slow-growing br ...	2004	15612629
phenotypic and genotypic characterization of rhizobia from diverse geographical origin that nodulate pachyrhizus species.	legumes from the genus pachyrhizus, commonly known as yam bean, are cultivated in several countries from the american continent and constitute an alternative source for sustainable starch, oil and protein production. the endosymbionts of these legumes have been poorly studied although it is known that this legume is nodulated by fast and slow growing rhizobia. in this study we have analyzed a collection of strains isolated in several countries using different phenotypic and molecular methods. th ...	2004	15612632
two heme binding sites are involved in the regulated degradation of the bacterial iron response regulator (irr) protein.	the iron response regulator (irr) protein from bradyrhizobium japonicum is a conditionally stable protein that degrades in response to cellular iron availability. this turnover is heme-dependent, and rapid degradation involves heme binding to a heme regulatory motif (hrm) of irr. here, we show that irr confers iron-dependent instability on glutathione s-transferase (gst) when fused to it. analysis of irr-gst derivatives with c-terminal truncations of irr implicated a second region necessary for ...	2004	15613477
ectomycorrhizal symbiosis enhanced the efficiency of inoculation with two bradyrhizobium strains and acacia holosericea growth.	two strains of bradyrhizobium sp., aust 13c and aust 11c, were dually or singly inoculated with an ectomycorrhizal fungus, pisolithus albus to assess the interactions between ectomycorrhizal symbiosis and the nodulation process in glasshouse conditions. sequencing of strains aust 13c and aust 11c confirmed their previous placement in the genus bradyrhizobium. after 4 months' culture, the ectomycorrhizal symbiosis promoted plant growth and the nodulation process of both bradyrhizobium strains, si ...	2004	15616831
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
infection and invasion of roots by symbiotic, nitrogen-fixing rhizobia during nodulation of temperate legumes.	bacteria belonging to the genera rhizobium, mesorhizobium, sinorhizobium, bradyrhizobium, and azorhizobium (collectively referred to as rhizobia) grow in the soil as free-living organisms but can also live as nitrogen-fixing symbionts inside root nodule cells of legume plants. the interactions between several rhizobial species and their host plants have become models for this type of nitrogen-fixing symbiosis. temperate legumes such as alfalfa, pea, and vetch form indeterminate nodules that aris ...	2004	15187185
use of tn kpk2 for sequencing a 10.6-kb psti dna fragment of bradyrhizobium japonicum and for the construction of aspa and ndva mutants.	transposon tn kpk2 was used to saturate a randomly cloned bradyrhizobium japonicum psti fragment and the insertions were used as starting points for the sequence determination. the first gene of the 10.6-kb dna insert encodes a homologue to ndva, the product of which is known to be involved in the formation of periplasmic cyclic glucans. selected tn kpk2 insertions were introduced into the b. japonicum wild-type strain. the resulting mutants were subsequently tested for their symbiotic interacti ...	2004	15188087
integrative plasmid vector for constructing single-copy reporter systems to study gene regulation in rhizobium meliloti and related species.	the integrative system of phage 16-3 of rhizobium meliloti 41 was shown to function in several bacterial species belonging to the rhizobium, bradyrhizobium, azorhizobium, and agrobacterium genera. it might also function in many other bacterial species provided that both the target site (attb) and the required host factor(s) are present. here we report on the construction of a new integrative vector that can be utilized in gene regulation studies. it provides an opportunity to create a single-cop ...	2004	15212892
rrna and dnak relationships of bradyrhizobium sp. nodule bacteria from four papilionoid legume trees in costa rica.	enzyme electrophoresis and sequencing of rrna and dnak genes revealed high genetic diversity among root nodule bacteria from the costa rican trees andira inermis, dalbergia retusa, platymiscium pinnatum (papilionoideae tribe dalbergieae) and lonchocarpus atropurpureus (papilionoideae tribe millettieae). a total of 21 distinct multilocus genotypes [ets (electrophoretic types)] was found among the 36 isolates analyzed, and no ets were shared in common by isolates from different legume hosts. howev ...	2004	15214639
characterisation of wild legume nodulating bacteria (lnb) in the infra-arid zone of tunisia.	we report on the isolation and the characterization of nitrogen-fixing root nodule bacteria isolated from natural legumes in a region of south tunisia corresponding to the infra-arid climatic zone. a collection of 60 new bacterial root nodule isolates were obtained from 19 legume species belonging to the genera acacia, anthyllis, argyrolobium, astragalus, calycotome, coronilla, ebenus, genista, hedysarum, hippocrepis, lathyrus, lotus, medicago, ononis. the isolates were characterised by (1) comp ...	2004	15214644
impact of glyphosate on the bradyrhizobium japonicum symbiosis with glyphosate-resistant transgenic soybean: a minireview.	glyphosate-resistant (gr) soybean [glycine max (l.) merr.] expressing an insensitive 5-enolpyruvylshikimic acid-3-phosphate synthase (epsps) gene has revolutionized weed control in soybean production. the soybean nitrogen fixing symbiont, bradyrhizobium japonicum, possesses a glyphosate-sensitive enzyme and upon exposure to glyphosate accumulates shikimic acid and hydroxybenzoic acids such as protocatechuic acid (pca), accompanied with b. japonicum growth inhibition and death at high concentrati ...	2004	15224916
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
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