| 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 |
| 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 |
| 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 |
| population genetics and phylogenetic inference in bacterial molecular systematics: the roles of migration and recombination in bradyrhizobium species cohesion and delineation. | a combination of population genetics and phylogenetic inference methods was used to delineate bradyrhizobium species and to uncover the evolutionary forces acting at the population-species interface of this bacterial genus. maximum-likelihood gene trees for atpd, glnii, reca, and nifh loci were estimated for diverse strains from all but one of the named bradyrhizobium species, and three unnamed "genospecies," including photosynthetic isolates. topological congruence and split decomposition analy ... | 2005 | 15579380 |
| 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 |
| phylogenetic analysis of the genera bradyrhizobium, mesorhizobium, rhizobium and sinorhizobium on the basis of 16s rrna gene and internally transcribed spacer region sequences. | a total of 128 strains was isolated from more than 23 legume hosts in korea. phylogenetic relationships between these korean isolates and reference strains of the genera bradyrhizobium, mesorhizobium, rhizobium and sinorhizobium were analysed using their 16s rrna gene and internally transcribed spacer (its) region sequences. among the bradyrhizobium strains, dendrograms based on both the 16s rrna gene and its region sequences produced two main groups. the its tree yielded at least two new cluste ... | 2005 | 15653885 |
| biodiversity of uptake hydrogenase systems from legume endosymbiotic bacteria. | uptake hydrogenases in legume endosymbiotic bacteria recycle hydrogen produced during the nitrogen fixation process in legume nodules. despite the described beneficial effect on plant productivity, the hydrogen oxidation capability is not widespread in the rhizobiaceae family. characterization of hydrogenase gene clusters in strains belonging to rhizobium, bradyrhizobium and azorhizobium reveals a similar overall genetic organization along with important differences in gene regulation. in additi ... | 2005 | 15667257 |
| molecular characterization of uptake hydrogenase in frankia. | a molecular characterization of uptake hydrogenase in frankia was performed by using two-dimensional gel electrophoresis, matrix-assisted laser-desorption ionization-time-of-flight mass spectrometry, pcr amplification and southern blotting. a polypeptide of approx. 60 kda was recognized in frankia ugl011102, avci1 and kb5 on the two-dimensional gel by blotting with ralstonia eutropha (hox g) antibody. further analysis by ms resulted in a peptide 'fingerprint', which was similar to the membrane-b ... | 2005 | 15667266 |
| molybdate-dependent expression of the periplasmic nitrate reductase in bradyrhizobium japonicum. | the napedabc genes of bradyrhizobium japonicum encode the periplasmic nitrate reductase, an mo-containing enzyme which catalyses the reduction of nitrate to nitrite when oxygen concentrations are limiting. in this bacterium, another set of genes, modabc, code for a high affinity abc-type mo transport system. a b. japonicum moda mutant has been obtained that is not capable of growing anaerobically with nitrate and lacks nitrate reductase activity. under nitrate respiring conditions, when mo conce ... | 2005 | 15667283 |
| the complete denitrification pathway of the symbiotic, nitrogen-fixing bacterium bradyrhizobium japonicum. | denitrification is an alternative form of respiration in which bacteria sequentially reduce nitrate or nitrite to nitrogen gas by the intermediates nitric oxide and nitrous oxide when oxygen concentrations are limiting. in bradyrhizobium japonicum, the n(2)-fixing microsymbiont of soya beans, denitrification depends on the napedabc, nirk, norcbqd, and nosrzdfylx gene clusters encoding nitrate-, nitrite-, nitric oxide- and nitrous oxide-reductase respectively. mutational analysis of the b. japoni ... | 2005 | 15667287 |
| simultaneous enumeration of different bacteria using reverse sample genome probing technique. | quantitative reverse sample genome probing (rsgp) with lambdadna as an internal standard was used to enumerate the total numbers of rhizobium sp. ccrc 13560, rhizobium meliloti ccrc 13516 and bradyrhizobium sp. ccrc 13585. k(lambda)/kx ratios varied between the three species but also in response to the amounts of lambdadna or genomic dna used in the labeling mixture or fixed upon the membrane. comparative enumerations of pure cultures revealed higher counts using genomic probing as compared with ... | 2005 | 15676199 |
| novel avidin-like protein from a root nodule symbiotic bacterium, bradyrhizobium japonicum. | bradyrhizobium japonicum is an important nitrogenfixing symbiotic bacterium, which can form root nodules on soybeans. these bacteria have a gene encoding a putative avidin- and streptavidin-like protein, which bears an amino acid sequence identity of only about 30% over the core regions with both of them. we produced this protein in escherichia coli both as the full-length wild type and as a c-terminally truncated core form and showed that it is indeed a high affinity biotin-binding protein that ... | 2005 | 15695809 |
| prevalence of burkholderia sp. nodule symbionts on four mimosoid legumes from barro colorado island, panama. | sequences of 16s rrna and partial 23s rrna genes and pcr assays with genotype-specific primers indicated that bacteria in the genus burkholderia were the predominant root nodule symbionts for four mimosoid legumes (mimosa pigra, m. casta, m. pudica, and abarema macradenia) on barro colorado island, panama. among 51 isolates from these and a fifth mimosoid host (pithecellobium hymenaeafolium), 44 were burkholderia strains while the rest were placed in rhizobium, mesorhizobium, or bradyrhizobium. ... | 2005 | 15709366 |
| role of arginine 220 in the oxygen sensor fixl from bradyrhizobium japonicum. | in the heme-based oxygen sensor protein fixl, conformational changes induced by oxygen binding to the heme sensor domain regulate the activity of a neighboring histidine kinase, eventually restricting expression of specific genes to hypoxic conditions. the conserved arginine 220 residue is suggested to play a key role in the signal transduction mechanism. to obtain detailed insights into the role of this residue, we replaced arg(220) by histidine (r220h), glutamine (r220q), glutamate (r220e), an ... | 2005 | 15711013 |
| insights into the domains required for dimerization and assembly of human alphab crystallin. | protein pin array technology was used to identify subunit-subunit interaction sites in the small heat shock protein (shsp) alphab crystallin. subunit-subunit interaction sites were defined as consensus sequences that interacted with both human alphaa crystallin and alphab crystallin. the human alphab crystallin protein pin array consisted of contiguous and overlapping peptides, eight amino acids in length, immobilized on pins that were in a 96-well elisa plate format. the interaction of alphab c ... | 2005 | 15722445 |
| snp identification and snap marker development for a gmnark gene controlling supernodulation in soybean. | supernodulation in soybean (glycine max l. merr.) is an important source of nitrogen supply to subterranean ecological systems. single nucleotide-amplified polymorphism (snap) markers for supernodulation should allow rapid screening of the trait in early growth stages, without the need for inoculation and phenotyping. the gene gmnark (glycine max nodule autoregulation receptor kinase), controlling autoregulation of nodulation, was found to have a single nucleotide polymorphism (snp) between the ... | 2005 | 15731930 |
| occurrence of nodulation in unexplored leguminous trees native to the west african tropical rainforest and inoculation response of native species useful in reforestation. | despite the abundance and diversity of timber tree legumes in the west african rainforest, their ability to form nitrogen-fixing nodules in symbiosis with rhizobia, and their response to rhizobial inoculation, remain poorly documented. in the first part of this study the occurrence of nodulation was determined in 156 leguminous species growing in six natural forest areas in guinea, mostly mature trees. in the second part, an in situ experiment of rhizobial inoculation was performed on eight sele ... | 2005 | 15760366 |
| bradyrhizobium canariense sp. nov., an acid-tolerant endosymbiont that nodulates endemic genistoid legumes (papilionoideae: genisteae) from the canary islands, along with bradyrhizobium japonicum bv. genistearum, bradyrhizobium genospecies alpha and bradyrhizobium genospecies beta. | highly diverse bradyrhizobium strains nodulate genistoid legumes (brooms) in the canary islands, morocco, spain and the americas. phylogenetic analyses of its, atpd, glnii and reca sequences revealed that these isolates represent at least four distinct evolutionary lineages within the genus, namely bradyrhizobium japonicum and three unnamed genospecies. dna-dna hybridization experiments confirmed that one of the latter represents a new taxonomic species for which the name bradyrhizobium canarien ... | 2005 | 15774626 |
| crystal structures of deoxy and co-bound bjfixlh reveal details of ligand recognition and signaling. | rhizobia directly regulate the expression of genes required for symbiotic nitrogen fixation in response to oxygen concentration via the sensor protein fixl. the n-terminal pas domain of fixl contains a histidine-coordinated heme and regulates the activity of its effector domain, a c-terminal histidine kinase, in response to binding of oxygen and other ligands at the heme. to further investigate ligand-induced inhibition of fixl, we have determined the crystal structures of the heme domain in bot ... | 2005 | 15779889 |
| insights into heme-based o2 sensing from structure-function relationships in the fixl proteins. | fixl proteins are bacterial heme-containing signal transduction proteins responsible for sensing the o(2) concentration in the organism's environment. in sinorhizobium meliloti fixl is a protein histidine kinase that, together with its response regulator fixj, constitute an oxygen-sensitive switch for regulation of the organism's nitrogen fixation and microaerobic respiration genes. the o(2) sensitivity of the switch is such that it transitions during the process of symbiosis in alfalfa roots. b ... | 2005 | 15811514 |
| genetic diversity of benzoyl coenzyme a reductase genes detected in denitrifying isolates and estuarine sediment communities. | benzoyl coenzyme a (benzoyl-coa) reductase is a central enzyme in the anaerobic degradation of organic carbon, which utilizes a common intermediate (benzoyl-coa) in the metabolism of many aromatic compounds. the diversity of benzoyl-coa reductase genes in denitrifying bacterial isolates capable of degrading aromatic compounds and in river and estuarine sediment samples from the arthur kill in new jersey and the chesapeake bay in maryland was investigated. degenerate primers were developed from t ... | 2005 | 15812036 |
| transcription activation in vitro by the bradyrhizobium japonicum regulatory protein fixk2. | in bradyrhizobium japonicum, the n2-fixing root nodule endosymbiont of soybean, a group of genes required for microaerobic, anaerobic, or symbiotic growth is controlled by fixk2, a key regulator that is part of the fixlj-fixk2 cascade. fixk2 belongs to the family of cyclic amp receptor protein/fumarate and nitrate reductase (crp/fnr) transcription factors that recognize a palindromic dna motif (crp/fnr box) associated with the regulated promoters. here, we report on a biochemical analysis of fix ... | 2005 | 15866917 |
| soybean genotypic difference in growth, nutrient accumulation and ultrastructure in response to manganese and iron supply in solution culture. | * | 2005 | 15897206 |
| diverse bacteria isolated from root nodules of phaseolus vulgaris and species within the genera campylotropis and cassia grown in china. | eighty bacterial isolates from root nodules of the leguminous plants phaseolus vulgaris, campylotropis spp. and cassia spp. grown in china were classified into five groups by phenotypic analyses, sds-page of whole-cell proteins, pcr-based 16s rrna gene restriction-fragment-length-polymorphism and sequencing. thirty-three isolates from the three plant genera were identified as agrobacterium tumefaciens because they are closely related to the type strain of a. tumefaciens. fourteen isolates from p ... | 2005 | 15900972 |
| evaluation of the role of genes encoding for dehydrin proteins (lea d-11) during drought stress in arbuscular mycorrhizal glycine max and lactuca sativa plants. | in this study, it has been determined whether the arbuscular mycorrhizal (am) symbiosis is able to alter the pattern of dehydrin (lea d-11 group) transcript accumulation under drought stress, and whether such a possible alteration functions in the protection of the host plants against drought. two dehydrin-encoding genes have been cloned from glycine max (gmlea 8 and gmlea 10) and one from lactuca sativa (lslea 1) and they have been analysed for their contribution to the response against drought ... | 2005 | 15911559 |
| proteomic analysis of soybean root hairs after infection by bradyrhizobium japonicum. | infection of soybean root hairs by bradyrhizobium japonicum is the first of several complex events leading to nodulation. in the current proteomic study, soybean root hairs after inoculation with b. japonicum were separated from roots. total proteins were analyzed by two-dimensional (2-d) polyacrylamide gel electrophoresis. in one experiment, 96 protein spots were analyzed by matrix-assisted laser desorption ionization time-of-flight (maldi-tof) mass spectrometry (ms) to compare protein profiles ... | 2005 | 15915644 |
| effect of chlorimuron-ethyl on bradyrhizobium japonicum and its symbiosis with soybean. | possible side-effects of the acetolactate synthase (als)-inhibiting herbicide chlorimuron-ethyl on bradyrhizobium japonicum (kirchner & jordan) in pure culture and on inoculated soybean plants growing under controlled conditions were investigated. growth of b japonicum strain e109 was not affected by this herbicide even when exposed to concentrations 150 times higher than recommended field doses. however, nodulation of soybean plants treated 5 days after emergence with chlorimuron-ethyl at stand ... | 2005 | 15920784 |
| new evidence for bacterial diversity in the ascoma of the ectomycorrhizal fungus tuber borchii vittad. | the microbial community associated with ascocarps of the ectomycorrhizal fungus tuber borchii vittad. was studied by both cultivation and direct extraction of bacterial 16s rrna gene (rdna) sequence approaches. the inner part of six t. borchii ascoma collected in north-central italy was used to establish a bacterial culture collection and to extract the total genomic dna to obtain a library of 16s rdnas representative of the truffle bacterial community. most of the isolates were affiliated to th ... | 2005 | 15927744 |
| recombinant pas-heme domains of oxygen sensing proteins: high level production and physical characterization. | details of a high-level recombinant production method for the heme-pas domains of heme oxygen sensing proteins from sinorhizobium meliloti (sm) (formerly rhizobium meliloti, rm), bradyrhizobium japonicum (bj), and escherichia coli (ec) are described. using a newly proposed, concise, and unambiguous naming system (also described here) these proteins are: smfixlh(128-264), bjfixlh(140-270), and ecdosh(1-147). in addition, high-level production of bjfixl(140-505), the soluble full-length protein co ... | 2005 | 15939306 |
| ppsr: a multifaceted regulator of photosynthesis gene expression in purple bacteria. | purple bacteria control the level of expression and the composition of their photosystem according to light and redox conditions. this control involves several regulatory systems that have been now well characterized. among them, the ppsr regulator plays a central role, because it directly or indirectly controls the synthesis of all of the different components of the photosystem. in this review, we report our knowledge of the ppsr protein, highlighting the diversity of its mode of action and foc ... | 2005 | 15948946 |
| the pleiotropic nature of symbiotic regulatory mutants: bradyrhizobium japonicum nifa gene is involved in control of nif gene expression and formation of determinate symbiosis. | in the slow-growing soybean symbiont, bradyrhizobium japonicum (strain 110), a nifa-like regulatory gene was located immediately upstream of the previously mapped fixa gene. by interspecies hybridization and partial dna sequencing the gene was found to be homologous to nifa from klebsiella pneumoniae and rhizobium meliloti, and to a lesser extent, also to ntrc from k. pneumoniae. the b. japonicum nifa gene product was shown to activate b. japonicum and k. pneumoniae nif promoters (using nif::lac ... | 1986 | 15966104 |
| characterization of a bifunctional puta homologue from bradyrhizobium japonicum and identification of an active site residue that modulates proline reduction of the flavin adenine dinucleotide cofactor. | puta is a bifunctional flavoenzyme in bacteria that catalyzes the four-electron oxidation of proline to glutamate. in certain prokaryotes such as escherichia coli, puta is also a transcriptional repressor of the proline utilization (put) genes and thus is trifunctional. in this work, we have begun to assess differences between bifunctional and trifunctional puta enzymes by examining the puta protein from bradyrhizobium japonicum (bjputa). primary structure analysis of bjputa shows it lacks the d ... | 2005 | 15966737 |
| pyd genes of rhizobium sp. strain tal1145 are required for degradation of 3-hydroxy-4-pyridone, an aromatic intermediate in mimosine metabolism. | rhizobium sp. strain tal1145 degrades the leucaena toxin mimosine and its degradation product 3-hydroxy-4-pyridone (hp). the aim of this investigation is to characterize the rhizobium genes for hp degradation and transport. these genes were localized by subcloning and mutagenesis on a previously isolated cosmid, puhr263, containing mid genes of tal1145 required for mimosine degradation. two structural genes, pyda and pydb, encoding a metacleavage dioxygenase and a hydrolase, respectively, are re ... | 2005 | 15968058 |
| l: -stereoselective amino acid amidase with broad substrate specificity from brevundimonas diminuta: characterization of a new member of the leucine aminopeptidase family. | brevundimonas diminuta tpu 5720 produces an amidase acting l-stereoselectively on phenylalaninamide. the enzyme (laaa(bd)) was purified to electrophoretic homogeneity by ammonium sulfate fractionation and four steps of column chromatography. the final preparation gave a single band on sds-page with a molecular weight of approximately 53,000. the native molecular weight of the enzyme was about 288,000 based on gel filtration chromatography, suggesting that the enzyme is active as a homohexamer. i ... | 2006 | 16001251 |
| genetic diversity and phylogeny of rhizobia isolated from agroforestry legume species in southern ethiopia. | the genetic diversity within 195 rhizobial strains isolated from root nodules of 18 agroforestry species (15 woody and three herbaceous legumes) growing in diverse ecoclimatic zones in southern ethiopia was investigated by using pcr-rflp of the ribosomal operon [16s rrna gene, 23s rrna gene and the internal transcribed spacer (its) region between the 16s rrna and 23s rrna genes] and 16s rrna gene partial sequence (800 and 1350 bp) analyses. all of the isolates and the 28 reference strains could ... | 2005 | 16014464 |
| [study of chemotaxis of nodule bacteria of lupin to organic substances]. | ability of different strains (359a, 400, 176, 365a) of nodule bacteria of lupin bradyrhizobium sp. (lupinus), which differ in symbiotic properties (competitiveness and nitrogen-fixing activity), to chemotaxis with respect to the organic substances revealed in root exudates of lupin (aminoacids, sugars, organic acids and their salts) has been investigated. it is shown, that alongside with the substances to which rhizobia of lupin, irrespective of their symbiotic properties, show the chemotaxic re ... | 2005 | 16018202 |
| iron-dependent cytochrome c1 expression is mediated by the status of heme in bradyrhizobium japonicum. | the heme prosthetic group of heme proteins contains iron, which can be a limiting nutrient. here, we show that cytochrome c1 protein from bradyrhizobium japonicum was strongly affected by the iron status, with low expression in cells grown under iron limitation. this control was not affected in mutants encoding the iron regulator irr or fur. furthermore, cytochrome c1 mrna was not influenced by the iron status, suggesting control at a posttranscriptional step. cytochrome c1 protein levels were v ... | 2005 | 16030200 |
| characterization of conformational changes coupled to ligand photodissociation from the heme binding domain of fixl. | using transient absorption spectroscopy and photoacoustic calorimetry (pac), we have characterized carbon monoxide photodissociation and rebinding to two forms of the heme domain of bradyrhizobium japonicum fixl. transient absorption results for the complete heme domain (fixl residues 140-270) and a truncated heme domain (missing 11 residues on the n-teminal end and 14 amino acid residues on the c-terminal end of the full length heme domain) show similar rates for ligand rebinding to the five-co ... | 2005 | 16042379 |
| comparative analyses of codon and amino acid usage in symbiotic island and core genome in nitrogen-fixing symbiotic bacterium bradyrhizobium japonicum. | genes involved in the symbiotic interactions between the nitrogen-fixing endosymbiont bradyrhizobium japonicum, and its leguminous host are mostly clustered in a symbiotic island (si), acquired by the bacterium through a process of horizontal transfer. a comparative analysis of the codon and amino acid usage in core and si genes/proteins of b. japonicum has been carried out in the present study. the mutational bias, translational selection, and gene length are found to be the major sources of va ... | 2005 | 16060695 |
| two rhizobial strains, mesorhizobium loti maff303099 and bradyrhizobium japonicum usda110, encode haloalkane dehalogenases with novel structures and substrate specificities. | haloalkane dehalogenases are key enzymes for the degradation of halogenated aliphatic pollutants. two rhizobial strains, mesorhizobium loti maff303099 and bradyrhizobium japonicum usda110, have open reading frames (orfs), mlr5434 and blr1087, respectively, that encode putative haloalkane dehalogenase homologues. the crude extracts of escherichia coli strains expressing mlr5434 and blr1087 showed the ability to dehalogenate 18 halogenated compounds, indicating that these orfs indeed encode haloal ... | 2005 | 16085827 |
| diverse rhizobia associated with woody legumes wisteria sinensis, cercis racemosa and amorpha fruticosa grown in the temperate zone of china. | fifty-nine bacterial isolates from root nodules of the woody legumes wisteria sinensis, cercis racemosa and amorpha fruticosa grown in the central and eastern regions of china were characterized with phenotypic analysis, pcr-based 16s and 23s rrna gene rflp, box pcr and 16s rrna gene sequencing. seven main phena were defined in numerical taxonomy, which corresponded to distinct groups within the genera agrobacterium, bradyrhizobium, mesorhizobium and rhizobium in 16s and 23s rrna gene pcr-rflp. ... | 2005 | 16094873 |
| compared tolerance to osmotic stress in various microorganisms: towards a survival prediction test. | the osmotic tolerance of microbial cells of different microorganisms was investigated as a function of glycerol concentration and temperatures. cells displayed specific sensitivity to dehydration in glycerol solutions. the viability of gram-negative strains (escherichia coli, bradyrhizobium japonicum), gram-positive strains (lactobacillus plantarum, l. bulgaricus), and yeasts (saccharomyces cerevisiae, candida utilis) decreased with increasing osmotic pressure. for each strain, a characteristic ... | 2005 | 16116658 |
| characterization of phages virulent for sarothamnus scoparius bradyrhizobia. | four virulent phages--phidl, phitl, phicyt21, and phios6, infective on sarothamnus scoparius rhizobia--were isolated from the soil and characterized for morphology, host range, rate of adsorption to bacterial cells, and genome size. new phages were separated into two morphological families: siphoviridae with long, noncontractile tails (phidl, phitl) and myoviridae with long, contractile tails (phicyt21, phios6). they were also classified into two groups by a host specificity. one of them include ... | 2005 | 16132456 |
| detection of homoserine lactone-like quorum sensing molecules in bradyrhizobium strains. | one hundred and forty-two bradyrhizobium strains were screened for their ability to produce n-acyl homoserine lactone-like molecules (ahls) by using an agrobacterium tumefaciens biosensor strain containing a trai-lacz fusion. approximately 22% (31 of 142) of the tested strains produced ahls that induced moderate to elevated beta-galactosidase activity levels in the biosensor strain. bradyrhizobium japonicum and bradyrhizobium elkanii strains were both shown to produce ahls. age of culture, and m ... | 2005 | 16132457 |
| an iron uptake operon required for proper nodule development in the bradyrhizobium japonicum-soybean symbiosis. | rhizobia live in the soil or enter into a nitrogen-fixing symbiosis with a suitable host plant. each environment presents different challenges with respect to iron acquisition. the soybean symbiont bradyrhizobium japonicum 61a152 can utilize a variety of siderophores (fe[iii]-specific ligands). purification of iron-regulated outer membrane proteins had previously allowed the cloning of a gene, fega, from b. japonicum 61a152, whose predicted protein shares significant amino acid similarity with k ... | 2005 | 16167765 |
| nh4+ currents across the peribacteroid membrane of soybean. macroscopic and microscopic properties, inhibition by mg2+, and temperature dependence indicate a subpicosiemens channel finely regulated by divalent cations. | the control of ammonium (nh(4)(+)) transport is critical in preventing futile cycles of nh(4)(+)/ammonia transport. an unusual nonselective cation channel with subpicosiemens single-channel conductance permeable to nh(4)(+) had previously been identified in the peribacteroid membrane (pbm) of symbiosomes from soybean (glycine max) nodules. here, we investigate the proposed channel mechanism and its control by luminal magnesium. currents carried by nh(4)(+) were measured in inside-out pbm patches ... | 2005 | 16183839 |
| dimeric brucella abortus irr protein controls its own expression and binds haem. | brucella abortus needs to synthesize haem in order to replicate intracellularly and to produce virulence in mice. thus, to gain insight into the pathogenesis of the bacterium, regulatory proteins of the haem biosynthetic pathway were sought. an iron response regulator (irr) from bradyrhizobium japonicum, which is a close relative of brucella, was previously described as being involved in the coordination of haem biosynthesis and iron availability. the bru. abortus genome was searched for an irr ... | 2005 | 16207924 |
| the crystal structure of mismatch-specific uracil-dna glycosylase (mug) from deinococcus radiodurans reveals a novel catalytic residue and broad substrate specificity. | deinococcus radiodurans is extremely resistant to the effects of ionizing radiation. the source of the radiation resistance is not known, but an expansion of specific protein families related to stress response and damage control has been observed. dna repair enzymes are among the expanded protein families in d. radiodurans, and genes encoding five different uracil-dna glycosylases are identified in the genome. here we report the three-dimensional structure of the mismatch-specific uracil-dna gl ... | 2006 | 16223719 |
| denaturing gradient gel electrophoresis analyses of microbial community from field-scale composter. | the diversity of microbial community during the decomposition of waste in a field-scale composter (hazaka system) was investigated by denaturing gradient gel electrophoresis (dgge). the composter operates at a high temperature through a self-heating system, creating a thermophilic (60-76 degrees c) stage during the initial phase and a mesophilic (45 degrees c) stage towards the later phase of the composting period. the ph of the system (ph 7.75-8.10) did not vary significantly during the process ... | 2001 | 16232968 |
| analysis of genetic relationship of sarothamnus scoparius microsymbionts and bradyrhizobium sp. by hybridization in microdilution wells. | dna-dna hybridization in microdilution wells was successfully used to determine the overall genomic similarity among sarothamnus scoparius microsymbionts isolated from poland and japan and representatives of bradyrhizobium species including bradyrhizobium sp. (lupinus) usda3045. geographically different s. scoparius rhizobia diverged into two genomospecies at the dna-dna similarity level of approximately 49%. polish isolates exhibited high dna similarity levels to the dna of bradyrhizobium japon ... | 2004 | 16233609 |
| isolation of novel bacteria and actinomycetes using soil-extract agar medium. | novel bacteria were discovered using an isolation technique consisting of (i) selection of microorganisms that grew on soil-extract agar medium, but not on conventional media, and (ii) detection of small microbial colonies with a microscope. three bacterial strains thus isolated were provisionally designated shinshu-th1, -th2, -th 3, and five actinomycete strains, shinshu-ms-01, -02, -03, -04, -05, respectively. sequence analysis of their 16s rdna showed that th1 had 95--96% homology with three ... | 2005 | 16233821 |
| [effect of plant growth regulators on physiological activity of bradyrhizobium japonicum ]. | influence of plant growth regulators ivin, emistim c, eney and agrostimulin on the biomass production and exopolymers synthesis of soybean nodule bacteria, which have contrasting symbiotic properties, and glutamine synthetase activity of their cell-free extracts were studied. it was shown that the processes of the biomass and exopolymers accumulation had an opposite direction. of all preparations only ivin and agrostimulin intensificol growth activity of the microorganisms under study. the level ... | 2005 | 16250234 |
| global protein expression pattern of bradyrhizobium japonicum bacteroids: a prelude to functional proteomics. | as a prelude to using functional proteomics towards understanding the process of symbiotic nitrogen fixation between the legume soybean and the soil bacteria bradyrhizobium japonicum, we examined the total protein expression pattern of the nodule bacteria, often referred to as bacteroids. a partial proteome map was constructed by separating the total bacteroid proteins using high-resolution 2-de. of the several hundred protein spots analyzed using pmf, 180 spots were tentatively identified by se ... | 2005 | 16254929 |
| nitrogen-fixing nodules from rose wood legume trees (dalbergia spp.) endemic to madagascar host seven different genera belonging to alpha- and beta-proteobacteria. | although legume biodiversity is concentrated in tropical regions, the majority of studies on legume nodulating bacteria (lnb) are focused on cultivated leguminous plants from temperate regions. however, recent works on tropical regions tend to indicate that the actual diversity of lnb is largely underestimated. in this study, we report the isolation and characterization of 68 nitrogen-fixing root nodule bacteria collected from eight endemic tree species of dalbergia in madagascar. the isolates w ... | 2005 | 16262864 |
| european origin of bradyrhizobium populations infecting lupins and serradella in soils of western australia and south africa. | we applied a multilocus phylogenetic approach to elucidate the origin of serradella and lupin bradyrhizobium strains that persist in soils of western australia and south africa. the selected strains belonged to different randomly amplified polymorphic dna (rapd)-pcr clusters that were distinct from rapd clusters of applied inoculant strains. phylogenetic analyses were performed with nodulation genes (noda, nodz, noll, noei), housekeeping genes (dnak, reca, glnii, atpd), and 16s-23s rrna intergen ... | 2005 | 16269740 |
| novel dna sequences from natural strains of the nitrogen-fixing symbiotic bacterium sinorhizobium meliloti. | variation in genome size and content is common among bacterial strains. identifying these naturally occurring differences can accelerate our understanding of bacterial attributes, such as ecological specialization and genome evolution. in this study, we used representational difference analysis to identify potentially novel sequences not present in the sequenced laboratory strain rm1021 of the nitrogen-fixing bacterium sinorhizobium meliloti. using strain rm1021 as the driver and the type strain ... | 2005 | 16269751 |
| three stages of a biofilm community developing at the liquid-liquid interface between polychlorinated biphenyls and water. | soil contaminated with polychlorinated biphenyls (pcb) was used as an inoculum to grow a complex biofilm community on pcb oil (aroclor 1242) on a substratum (permanox). the biofilm was monitored for 31 days by confocal laser scanning microscopy, community fingerprinting using single-strand conformational polymorphism (sscp), amplicons of the 16s rrna genes, and chemical analyses of the pcb congeners. sscp analysis of the young biofilm revealed a rather diverse microbial community with species of ... | 2005 | 16269772 |
| symbiotic hydrogenase activity in bradyrhizobium sp. (vigna) increases nitrogen content in vigna unguiculata plants. | bradyrhizobium sp. (lupinus) and bradyrhizobium sp. (vigna) mutants in which hydrogenase (hup) activity was affected were constructed and analyzed. vigna unguiculata plants inoculated with the bradyrhizobium sp. (vigna) hup mutant showed reduced nitrogenase activity and also a significant decrease in nitrogen content, suggesting a relevant contribution of hydrogenase activity to plant yield. | 2005 | 16269797 |
| nod factor induces soybean resistance to powdery mildew. | plants possess highly sensitive perception systems by which microbial signal molecules are recognized. in the bradyrhizobium-soybean (glycine max (l.) merr.) symbiosis, recognition is initiated through exchange of signal molecules, generally flavonoids from soybean and lipo-chitooligosaccharides (nod factors) from the microsymbiont. application of the nod factor nod bj-v (c18:1, mefuc) induced soybean resistance to powdery mildew caused by microsphaera diffusa. addition of nod factor (concentrat ... | 2005 | 16310369 |
| kinetic and thermodynamic analysis of bradyrhizobium japonicum puta-membrane associations. | in escherichia coli, proline induces tight membrane binding of the puta flavoenzyme and transforms puta from a transcriptional repressor to a membrane-associated proline catabolic enzyme. in other gram-negative bacteria such as bradyrhizobium japonicum, puta lacks dna binding activity and functions only as a proline catabolic enzyme. here, we characterize the membrane binding properties of puta from b. japonicum (bjputa) to address whether proline regulates bjputa-lipid binding similar to escher ... | 2006 | 16310755 |
| alterations induced by glyphosate on lupin photosynthetic apparatus and nodule ultrastructure and some oxygen diffusion related proteins. | the effects of glyphosate on protein metabolism, mesophyll cell ultrastructure and nodule ultrastructure and functioning of lupinus albus cv. multolupa inoculated with bradyrhizobium sp. (lupinus) were investigated. young leaves and nodules were especially affected because these organs act as sinks of the herbicide. the alterations on nodular and chloroplast ultrastructure varied depending on herbicide concentration and time of exposure. after 3 days of 2.5 mm glyphosate application some toxic e ... | 2005 | 16324849 |
| design and validation of a partial-genome microarray for transcriptional profiling of the bradyrhizobium japonicum symbiotic gene region. | the design and use of a pilot microarray for transcriptome analysis of the symbiotic, nitrogen-fixing bradyrhizobium japonicum is reported here. the custom-synthesized chip (affymetrix genechip) features 738 genes, more than half of which belong to a 400-kb chromosomal segment strongly associated with symbiosis-related functions. rna was isolated following an optimized protocol from wild-type cells grown aerobically and microaerobically, and from cells of aerobically grown regr mutant and microa ... | 2006 | 16328374 |
| the manganese-responsive repressor mur of rhizobium leguminosarum is a member of the fur-superfamily that recognizes an unusual operator sequence. | the manganese uptake regulator mur of rhizobium leguminosarum is a close homologue of the global iron regulatory protein fur. mur represses the sitabcd operon, which encodes a mn2+ transport system, specifically in response to mn2+ but not fe2+. in previous work the authors mapped the 5' ends of two sit operon transcripts, termed ts1 and ts2, which were co-ordinately regulated by mn2+-mur, but this paper now shows that only ts1 is a primary transcript. dnase i protection analyses showed that pur ... | 2005 | 16339952 |
| anaerobic growth and denitrification among different serogroups of soybean rhizobia. | we screened soybean rhizobia originating from three germplasm collections for the ability to grow anaerobically in the presence of no(3) and for differences in final product formation from anaerobic no(3) metabolism. denitrification abilities of selected strains as free-living bacteria and as bacteroids were compared. anaerobic growth in the presence of no(3) was observed in 270 of 321 strains of soybean rhizobia. all strains belonging to the 135 serogroup did not grow anaerobically in the prese ... | 1985 | 16346767 |
| rhizobins, a group of peptides in the free-amino-acid pool of the soybean-rhizobium system. | free-living rhizobium (according to bergey's manual of systematic bacteriology, [1984, the williams & wilkins co., baltimore], bradyrhizobium) japonicum was found to release a peptide into the nutrient media. soybean nodules contained this peptide and exuded it into the soil. the name "rhizobin a" is suggested for this peptide. nodules also contained another peptide, rhizobin b, as well as an unidentified, ninhydrin-positive compound, rhizobin c. the three peptides were confined to the free-amin ... | 1986 | 16347004 |
| restriction endonuclease and nif homology patterns of bradyrhizobium japonicum usda 110 derivatives with and without nitrogen fixation competence. | dnas from bradyrhizobium japonicum usda 110 derivatives that differ in nitrogen-fixing ability produced similar electrophoretic patterns with five different restriction enzymes. our data support the hypothesis of common ancestry for these derivatives. derivatives i-110 and l1-110 differed as much as 100-fold in acetylene reduction activity when they were tested with several soybean cultivars in both greenhouse and field experiments. while possessing nodulating ability, derivative l1-110 is defic ... | 1986 | 16347007 |
| identification of bradyrhizobium japonicum nodule isolates from wisconsin soybean farms. | one-dimensional sodium dodecyl sulfate-polyacrylamide gel electrophoresis was a more discriminating method than serotyping for identifying strains of bradyrhizobium japonicum. analysis of 543 nodule isolates from southeastern wisconsin soybean farms revealed that none of the isolates were formed by any of the inoculant strains supplied by either of two inoculant companies. twenty-nine indigenous strains and six inoculant strains were identified. strain 61a76, the most competitive indigenous stra ... | 1986 | 16347009 |
| improved method of typing bradyrhizobium japonicum in soybean nodules. | an improved method for antibiotic resistance recovery of bradyrhizobium japonicum from soybean (glycine max (l.) merr.) nodules that is simple, time saving, and economical was developed. this technique involves the use of two 96-well microtiter plates as a multinodule sterilization chamber and a template and a third plate as a 16-point replicator constructed with steel nails affixed to the plate with epoxy cement. with this system a team of four technicians could type 3,000 nodules per day. this ... | 1986 | 16347035 |
| asymbiotic acetylene reduction by a fast-growing cowpea rhizobium strain with nitrogenase structural genes located on a symbiotic plasmid. | a procedure was designed which enabled the detection of ex planta nitrogenase activity in the fast-growing cowpea rhizobium strain ihp100. nitrogenase activity in agar culture under air occurred at a rate similar to that found for bradyrhizobium strain cb756 but lower than that for rhizobium strain ors571. hybridization studies showed that both nod and nif genes were located on a 410-kilobase sym plasmid in strain ihp100. | 1986 | 16347045 |