| effectiveness of ascorbate and ascorbate peroxidase in promoting nitrogen fixation in model systems. | ascorbate and ascorbate peroxidase are important antioxidants that are abundant in n2-fixing legume root nodules. antioxidants are especially critical in root nodules because leghemoglobin, which is present at high concentrations in nodules, is prone to autoxidation and production of activated oxygen species such as o2.- and h2o2. the merits of ascorbate and ascorbate peroxidase for maintaining conditions favorable for n2 fixation were examined in two model systems containing oxygen-binding prot ... | 1999 | 10647213 |
| characterization of an azospirillum brasilense tn5 mutant with enhanced n(2) fixation: the effect of orf280 on nifh expression. | disruption of an open reading frame (orf) of 840 bp (280 amino acids; orf280) in an azospirillum brasilense tn5 mutant resulted in a pleiotrophic phenotype. besides an enhanced n(2)-fixing capacity and altered expression pattern of a nifh-gusa fusion, growth on the charged polar amino acids glutamate and arginine was severely affected. orf280, similar to previously identified orfs present in bradyrhizobium japonicum (orf277), paracoccus denitrificans (orf278) and rhodobacter capsulatus (orf277), ... | 2000 | 10650197 |
| two genes encoding a putative multidrug efflux pump of the rnd/mfp family are cotranscribed with an rpoh gene in bradyrhizobium japonicum. | the rpoh3 gene of bradyrhizobium japonicum codes for one of three sigma32-type transcription factors in this organism and is flanked by rag (rpoh3-associated) genes comprising the chromosomal arrangement ragabrpoh3ragcd. the first genes in this cluster code for a classical two-component regulatory system with an unknown function (narberhaus et al., 1997. mol. microbiol. 24, 93-104). the deduced proteins of the last two genes display a high sequence similarity to heavy metal or multidrug efflux p ... | 2000 | 10675036 |
| glyphosate effects on phenolic metabolism of nodulated soybean (glycine max l. merr.). | glyphosate is a herbicide that blocks the shikimic acid pathway. three bradyrhizobium japonicum strains with different sensitivities to glyphosate were used to test the effect of this herbicide on the phenolic metabolism of nodulated soybeans and on the bacteroid nitrogenase activity. glyphosate caused an inhibition in the bacteroid nitrogenase activity that was related with the sensitivity of the nodule-forming strains. both leaves and nodules accumulated huge amounts of shikimate and phenolic ... | 1999 | 10552587 |
| phylogeny and diversity of bradyrhizobium strains isolated from the root nodules of peanut (arachis hypogaea) in sichuan, china. | twenty-two rhizobial strains isolated from the root nodules of two chinese peanut cultivars (arachis hypogaea l. tianfu no. 3 and a local cultivar) growing at four different sites in the sichuan province, southwest china, were characterized by growth rate, rep-pcr, pcr-rflp of 16s rdna, partial sequencing of ribosomal genes, and fatty acid-methyl ester analysis (fame), and compared with strains representing bradyrhizobium japanicum, b. elkanii and other unclassified bradyrhizobium sp. all peanut ... | 1999 | 10553290 |
| influence of growth phases and desiccation on the degrees of unsaturation of fatty acids and the survival rates of rhizobia | the influence of growth phase on the evolution of cellular fatty acids (cfa) and survival of sinorhizobium and bradyrhizobium during desiccation and storage at different levels of relative humidity (r. h.) was studied. lactobacillic, cis vaccenic and palmitic acids were the major fatty acids of s. meliloti rcr 2011, b. elkanii usda 120 and b. japonicum 3.2, whatever the growth phase. an exchange of cis vaccenic with lactobacillic acid was observed during the course of growth. the degree of unsat ... | 1999 | 10583690 |
| role of hsfa gene on host-specificity by bradyrhizobium japonicum in a broad range of tropical legumes. | bradyrhizobium japonicum mutant strain nad163, containing a 30-kb deletion mutant encompassing the hsfa gene, was inoculated onto a broad range of legume species to test host-specificity. most legume species formed ineffective nodules except vigna angularis var. chibopat and glycine max var. pureunkong. a hsfa insertion mutant, bjjc211, gave similar results to strain nad163, implying that many legume species require hsfa for host-specific nitrogen fixation. to determine whether other genes in th ... | 2000 | 10696474 |
| nickel availability and hupsl activation by heterologous regulators limit symbiotic expression of the rhizobium leguminosarum bv. viciae hydrogenase system in hup(-) rhizobia. | a limited number of rhizobium and bradyrhizobium strains possess a hydrogen uptake (hup) system that recycles the hydrogen released from the nitrogen fixation process in legume nodules. to extend this ability to rhizobia that nodulate agronomically important crops, we investigated factors that affect the expression of a cosmid-borne hup system from rhizobium leguminosarum bv. viciae upm791 in r. leguminosarum bv. viciae, rhizobium etli, mesorhizobium loti, and sinorhizobium meliloti hup(-) strai ... | 2000 | 10698755 |
| molecular basis of symbiotic promiscuity. | eukaryotes often form symbioses with microorganisms. among these, associations between plants and nitrogen-fixing bacteria are responsible for the nitrogen input into various ecological niches. plants of many different families have evolved the capacity to develop root or stem nodules with diverse genera of soil bacteria. of these, symbioses between legumes and rhizobia (azorhizobium, bradyrhizobium, mesorhizobium, and rhizobium) are the most important from an agricultural perspective. nitrogen- ... | 2000 | 10704479 |
| the glutamine synthetases of rhizobia: phylogenetics and evolutionary implications. | glutamine synthetase exists in at least two related forms, gsi and gsii, the sequences of which have been used in evolutionary molecular clock studies. gsi has so far been found exclusively in bacteria, and gsii has been found predominantly in eukaryotes. to date, only a minority of bacteria, including rhizobia, have been shown to express both forms of gs. the sequences of equivalent internal fragments of the gsi and gsii genes for the type strains of 16 species of rhizobia have been determined ... | 2000 | 10677854 |
| reciprocal domain evolution within a transactivator in a restricted sequence space. | offhough the concept of domain merging and shuffling as a major force in protein evolution is well established, it has been difficult to demonstrate how domains coadapt. here we show evidence of coevolution of the sinorhizobium meliloti nifa (smnifa) domains. we found that, because of the lack of a conserved glycine in its dna-binding domain, this transactivator protein interacts weakly with the enhancers. this defect, however, was compensated by evolving a highly efficient activation domain tha ... | 2000 | 10716734 |
| the symbiotically essential cbb(3)-type oxidase of bradyrhizobium japonicum is a proton pump. | purified cbb(3)-type oxidase of bradyrhizobium japonicum was reconstituted into phospholipid vesicles. tight vesicles were obtained as shown by the disturbance of deltaph with cccp and the membrane potential with valinomycin, which led to a six-fold increase in cytochrome c oxidase activity. the vesicles were thus suitable for proton translocation experiments. in the presence of valinomycin, a pulse with reduced cytochrome c caused an acidification with a subsequent alkalinization, whereas the s ... | 2000 | 10722835 |
| bradyrhizobium japonicum isocitrate dehydrogenase exhibits calcium-dependent hysteresis. | bradyrhizobium japonicum nadp(+)-dependent isocitrate dehydrogenase was purified both from cultured cells and from the symbiotic form of the bacteria and was found to be identical in terms of n-terminal amino acid sequence, kinetics, and physicochemical properties. magnesium and glycerol were absolute requirements for maintaining enzyme activity. the n-terminal amino acid sequence of the enzyme was more similar to the sequences from soybean and yeast than to other bacterial sequences. there was ... | 2000 | 10729195 |
| fur-independent regulation of iron metabolism by irr in bradyrhizobium japonicum. | bradyrhizobium japonicum expresses both fur and irr, proteins that mediate iron-dependent regulation of gene expression. control of irr mrna accumulation by iron was aberrant in a fur mutant strain, and fur repressed an irr::lacz promoter fusion in the presence of iron. furthermore, metal-dependent binding of fur to an irr gene promoter was demonstrated in a region with no significant similarity to the fur-binding consensus dna element. these data suggest that the modest control of irr transcrip ... | 2000 | 10746770 |
| three new nifa-regulated genes in the bradyrhizobium japonicum symbiotic gene region discovered by competitive dna-rna hybridization. | the so-called symbiotic region of the bradyrhizobium japonicum chromosome (c. kündig, h. hennecke, and m. göttfert, j. bacteriol. 175:613-622, 1993) was screened for the presence of genes controlled by the nitrogen fixation regulatory protein nifa. southern blots of restriction enzyme-digested cosmids that represent an ordered, overlapping library of the symbiotic region were competitively hybridized with in vitro-labeled rna from anaerobically grown wild-type cells and an excess of rna isolated ... | 2000 | 10692350 |
| analysis of cellular fatty acids and phenotypic relationships of agrobacterium, bradyrhizobium, mesorhizobium, rhizobium and sinorhizobium species using the sherlock microbial identification system. | previous studies have demonstrated that cellular fatty acid analysis is a useful tool for identifying unknown strains of rhizobia and establishing taxonomic relationships between the species. in this study, the fatty acid profiles of over 600 strains belonging to the genera agrobacterium, bradyrhizobium, mesorhizobium, rhizobium and sinorhizobium were evaluated using the gaschromatography-based sherlock microbial identification system (mis). data collected with the mis showed that the three phyl ... | 2000 | 10758890 |
| catabolism of alpha-ketoglutarate by a suca mutant of bradyrhizobium japonicum: evidence for an alternative tricarboxylic acid cycle. | a complete tricarboxylic acid (tca) cycle is generally considered necessary for energy production from the dicarboxylic acid substrates malate, succinate, and fumarate. however, a bradyrhizobium japonicum suca mutant that is missing alpha-ketoglutarate dehydrogenase is able to grow on malate as its sole source of carbon. this mutant also fixes nitrogen in symbiosis with soybean, where dicarboxylic acids are its principal carbon substrate. using a flow chamber system to make direct measurements o ... | 2000 | 10781553 |
| carbon monoxide dehydrogenase activity in bradyrhizobium japonicum. | bradyrhizobium japonicum strain 110spc4 was capable of chemolithoautotrophic growth with carbon monoxide (co) as a sole energy and carbon source under aerobic conditions. the enzyme carbon monoxide dehydrogenase (codh; ec 1.2.99.2) has been purified 21-fold, with a yield of 16% and a specific activity of 58 nmol of co oxidized/min/mg of protein, by a procedure that involved differential ultracentrifugation, anion-exchange chromatography, hydrophobic interaction chromatography, and gel filtration ... | 2000 | 10788353 |
| a lipochito-oligosaccharide, nod factor, induces transient calcium influx in soybean suspension-cultured cells. | lipochito-oligosaccharides (nod factors) produced by rhizobium or bradyrhizobium are the key signal molecules for eliciting nodulation in their corresponding host legumes. to elucidate the signal transduction events mediated by nod factors, we investigated the effects of nod factors on the cytosolic [ca2+] of protoplasts prepared from roots and suspension-cultured cells of soybean (glycine max and g. soja) using a fluorescent ca2+ indicator, fura-pe3. nodbj-v (c18:1, mefuc), which is a major com ... | 2000 | 10792822 |
| diversity of bradyrhizobia from 27 tropical leguminosae species native of senegal | we isolated 71 slow-growing bacterial strains from nodules of 27 native leguminous plants species in senegal (west-africa) belonging to the genera abrus, alysicarpus, bryaspis, chamaecrista, cassia, crotalaria, desmodium, eriosema, indigofera, moghania, rhynchosia, sesbania, tephrosia, and zornia playing an ecological role and having agronomic potential in arid regions. the isolates were characterised by restriction fragment length polymorphism (rflp) analysis of pcr-amplified 16s rdna and compa ... | 1999 | 10794153 |
| bradyrhizobium spp. (tgx) isolates nodulating the new soybean cultivars in africa are diverse and distinct from bradyrhizobia that nodulate north american soybeans. | the newly developed cultivars of soybean in africa, known as tropical glycine cross (tgx), are nodulated by bradyrhizobia indigenous to african soils, here designated bradyrhizobium spp. (tgx). isolates of bradyrhizobium spp. (tgx) obtained from nodules of tgx soybeans that were inoculated with soils from 65 locations in six african countries were characterized and grouped into 11 phylogenetic clusters on the basis of rflp of the 16s rrna gene. five restriction enzymes (rsai, hinfi, mspi, cfoi a ... | 2000 | 10826808 |
| dual roles of bradyrhizobium japonicum nickelin protein in nickel storage and gtp-dependent ni mobilization. | the hydrogenase accessory protein hypb, or nickelin, has two functions in the n(2)-fixing, h(2)-oxidizing bacterium bradyrhizobium japonicum. one function of hypb involves the mobilization of nickel into hydrogenase. hypb also carries out a nickel storage/sequestering function in b. japonicum, binding nine nickel ions per monomer. here we report that the two roles (nickel mobilization and storage) of hypb can be separated in vitro and in vivo using molecular and biochemical approaches. the role ... | 2000 | 10692376 |
| relationships of bradyrhizobia from platypodium and machaerium (papilionoideae: tribe dalbergieae) on barro colorado island, panama. | enzyme electrophoresis and rrna sequencing indicated that root nodule bacteria from the canopy tree platypodium elegans and the lianas machaerium milleflorum and machaerium arboreum on barro colorado island, panama, were highly diverse on a local scale. a total of 11 distinct multilocus genotypes [ets (electrophoretic types)] was found among the 33 isolates analysed. on average, ets differed from one another at 74% of the 11 enzyme loci assayed, and separate nodules on a single host individual w ... | 2000 | 10843061 |
| sinorhizobium meliloti puta gene regulation: a new model within the family rhizobiaceae. | proline dehydrogenase (puta) is a bifunctional enzyme that catalyzes the oxidation of proline to glutamate. in sinorhizobium meliloti, as in other microorganisms, the puta gene is transcriptionally activated in response to proline. in rhodobacter capsulatus, agrobacterium, and most probably in bradyrhizobium, this activation is dependent on an lrp-like protein encoded by the putr gene, located immediately upstream of puta. interestingly, sequence and genetic analysis of the region upstream of th ... | 2000 | 10715000 |
| new mechanistic insights from structural studies of the oxygen-sensing domain of bradyrhizobium japonicum fixl. | the fixl heme domain serves as the dioxygen switch in the fixl/fixj two-component system of rhizobia. recent structural studies of the bradyrhizobium japonicum fixl heme domain (bjfixlh) have suggested an allosteric mechanism that is distinct from the classical hemoglobin model. to gain further insight into the fixl sensing mechanism, structures of bjfixlh bound to dioxygen, imidazole, and nitric oxide have been determined. these structures, particularly the structure of bjfixlh bound to its phy ... | 2000 | 10747783 |
| rhizobitoxine production by bradyrhizobium elkanii enhances nodulation and competitiveness on macroptilium atropurpureum. | application of 1-aminoocyclopropane-1-carboxylic acid, an ethylene precursor, decreased nodulation of macroptilium atropurpureum by bradyrhizobium elkanii. b. elkanii produces rhizobitoxine, an ethylene synthesis inhibitor. elimination of rhizobitoxine production in b. elkanii increased ethylene evolution and decreased nodulation and competitiveness on m. atropurpureum. these results suggest that rhizobitoxine enhances nodulation and competitiveness of b. elkanii on m. atropurpureum. | 2000 | 10831453 |
| isolation and characterization of canthaxanthin biosynthesis genes from the photosynthetic bacterium bradyrhizobium sp. strain ors278. | a carotenoid biosynthesis gene cluster involved in canthaxanthin production was isolated from the photosynthetic bradyrhizobium sp. strain ors278. this cluster includes five genes identified as crte, crty, crti, crtb, and crtw that are organized in at least two operons. the functional assignment of each open reading frame was confirmed by complementation studies. | 2000 | 10851005 |
| [the interaction of bradyrhizobium japonicum with clay minerals]. | it is shown that such clay minerals as palygorskite and montmorillonite stimulate growth activity of bradyrhizobium japonicum. the bacteria come into contact with the above minerals. granulated preparations of rhizobia have been developed on the basis of the results obtained. these preparations are characterized by the high yield of viable cells and a possibility of long-term storage. the use of montmorillonite in production of granulated preparations provides the higher yield of viable bacteria ... | 2000 | 10872286 |
| aflp fingerprint analysis of bradyrhizobium strains isolated from faidherbia albida and aeschynomene species. | the diversity of bradyrhizobium isolates from faidherbia albida and aeschynomenee species was assessed using aflp analysis, a high-resolution genomic fingerprinting technique. reference strains from bradyrhizobium japonicum, bradyrhizobium elkanii and bradyrhizobium liaoningense were included for comparison. at a similarity level of 50%, a total of 34 different groups were obtained by cluster analysis of the genomic fingerprints. four of these clusters correspond to the three reference species, ... | 2000 | 10879988 |
| [the population genetics of nodule bacteria]. | the data are reviewed on the population structure and evolutionary dynamics of the nodule bacteria (rhizobia) which are among the most intensively studied microorganisms. high level of the population polymorphism was demonstrated for the rhizobia populations using the enzyme electrophoresis (mlee profiles). the average value of nei's coefficient of heterogeneity (h = 1 - sigma pi2 [n/(n - 1)]) were: 0.590 for rhizobia (rhizobium, bradyrhizobium), 0.368 for enterobacteria (escherichia, salmonella ... | 2000 | 10863362 |
| differential degradation of escherichia coli sigma32 and bradyrhizobium japonicum rpoh factors by the ftsh protease. | the escherichia coli heat shock sigma factor sigma32 (rpoh) is rapidly degraded under non-stress conditions. the integrity of the dnak chaperone machinery and the atp-dependent ftsh protease are required for sigma32 proteolysis in vivo. bradyrhizobium japonicum expresses three sigma32-type transcription factors, rpoh1, rpoh2, and rpoh3, which are functional in e. coli. we compared the stability of these sigma factors with e. coli sigma32 stability. in e. coli c600 (wild-type), the half-lives of ... | 2000 | 10903518 |
| synthesis and accumulation of poly(3-hydroxybutyric acid) by rhizobium sp. | forty-two rhizobium strains obtained from different culture collections were evaluated quantitatively for poly(3-hydroxy-butyric acid) [phb] production in shake flask culture. the majority of the strains produced the maximum amount of phb during the late exponential or stationary phase of growth. synthesis and accumulation of phb in different species of rhizobium were found to vary between 1-38% of their dry biomass. growth and phb production by the rhizobium strain tal-640 were greatly influenc ... | 2000 | 10866363 |
| isolation and characterization of diverse halobenzoate-degrading denitrifying bacteria from soils and sediments. | denitrifying bacteria capable of degrading halobenzoates were isolated from various geographical and ecological sites. the strains were isolated after initial enrichment on one of the monofluoro-, monochloro-, or monobromo-benzoate isomers with nitrate as an electron acceptor, yielding a total of 33 strains isolated from the different halobenzoate-utilizing enrichment cultures. each isolate could grow on the selected halobenzoate with nitrate as the terminal electron acceptor. the isolates obtai ... | 2000 | 10919805 |
| stimulation of adhesiveness, infectivity, and competitiveness for nodulation of bradyrhizobium japonicum by its pretreatment with soybean seed lectin. | soybean seed lectin stimulates adsorption of bradyrhizobium japonicum to its host roots. pretreatment of the rhizobia with soybean seed lectin for at least 6-12 h previous to their interaction with the plants was required to detect the stimulatory effect. this activity could be observed with as few as 1000 soybean seed lectin molecules per bacterium, and required specific carbohydrate binding. infectivity and competitiveness for nodulation were also stimulated by preincubation of the rhizobia ei ... | 2000 | 10913702 |
| enhanced attachment of bradyrhizobium japonicum to soybean through reduced root colonization of internally seedborne microorganisms. | internally seedborne microorganisms are those surviving common surface sterilization procedures. such microbes often colonize the radicle surface of a germinating soybean (glycine max) seed, introducing an undefined parameter into studies on attachment and infection by bradyrhizobium japonicum. bacterial isolates from surface-sterilized soybean seed, cv. williams 82 and cv. maverick, used in our studies, were identified as agrobacterium radiobacter, aeromonas sp., bacillus spp., chryseomonas lut ... | 2000 | 10932352 |
| functional bradyrhizobium japonicum nifa expression under a hybrid nptii-nifh promoter in e. coli and acetobacter diazotrophicus srt4. | a hybrid promoter consisting of the in tandem fusion of the tn5 nptii and the klebsiella pneumoniae nifh promoters was constructed to study the functionality of the nif genes transcriptional activator nifa from bradyrhizobium japonicum in two different host bacteria. beta-galactosidase experiments in e. coli revealed that the hybrid nptii-nifh promoter can behave as a constitutive or a nifa-inducible promoter depending on the aeration conditions. expression of the b. japonicum nifa from the hybr ... | 1998 | 10932742 |
| altered exopolysaccharides of bradyrhizobium japonicum mutants correlate with impaired soybean lectin binding, but not with effective nodule formation. | the exact mechanism(s) of infection and symbiotic development between rhizobia and legumes is not yet known, but changes in rhizobial exopolysaccharides (epss) affect both infection and nodule development of the legume host. early events in the symbiotic process between bradyrhizobium japonicum and soybean (glycine max [l.] merr.) were studied using two mutants, defective in soybean lectin (sbl) binding, which had been generated from b. japonicum 2143 (usda 3i-1b-143 derivative) by tn5 mutagenes ... | 2000 | 10945216 |
| isolation and characterization of low-indole-3-acetic acid-producing mutants from bradyrhizobium elkanii. | we isolated 11 low-indole-3-acetic acid (iaa)-producing mutants of bradyrhizobium elkanii by tn5 mutagenesis. the amount of iaa produced by each mutant was 2.2-13.6% of that of the wild-type. it was found by resting cell reactions that the biosynthetic step to convert indole-3-pyruvic acid to indole-3-acetaldehyde was blocked in all the mutants. | 2000 | 10945251 |
| identification of active-site residues in bradyrhizobium japonicum malonyl-coenzyme a synthetase. | malonyl-coa synthetase (mcs) has been previously purified and characterized from bradyrhizobium japonicum usda 110. the gene encoding this enzyme is now cloned, sequenced, and expressed in escherichia coli. the enzyme contains 509 amino acid residues, with a calculated molecular mass of 55,239 da. the recombinant enzyme was also purified from the transformed e. coli. the enzyme was essentially indistinguishable from the mcs of b. japonicum by the criteria of polyacrylamide gel electrophoresis an ... | 2000 | 10871057 |
| identification of active-site residues in bradyrhizobium japonicum malonamidase e2. | malonamidase (ma) e2 was previously purified and characterized from bradyrhizobium japonicum usda 110. the gene encoding this enzyme has been cloned, sequenced and expressed in escherichia coli. the recombinant mae2 was purified to homogeneity from the transformed e. coli. the biochemical properties of the recombinant enzyme are essentially identical to those from wild-type b. japonicum. a database search showed that the mae2 protein has a high sequence similarity with the common signature seque ... | 2000 | 10880349 |
| effects of ethylene precursor and inhibitors for ethylene biosynthesis and perception on nodulation in lotus japonicus and macroptilium atropurpureum. | inhibitors of ethylene synthesis or its physiological function enhanced nodulation in lotus japonicus and macroptilium atropurpureum. in contrast, the application of 1-aminocyclopropane-1-carboxylic acid, a precursor of ethylene biosynthesis, reduced the nodule number in these legumes. these results suggest that an ethylene-mediated signaling pathway is involved in the nodulation process even in the determinate nodulators. | 2000 | 10965947 |
| genotypic characterization of bradyrhizobium strains nodulating small senegalese legumes by 16s-23s rrna intergenic gene spacers and amplified fragment length polymorphism fingerprint analyses. | we examined the genotypic diversity of 64 bradyrhizobium strains isolated from nodules from 27 native leguminous plant species in senegal (west africa) belonging to the genera abrus, alysicarpus, bryaspis, chamaecrista, cassia, crotalaria, desmodium, eriosema, indigofera, moghania, rhynchosia, sesbania, tephrosia, and zornia, which play an ecological role and have agronomic potential in arid regions. the strains were characterized by intergenic spacer (between 16s and 23s rrna genes) pcr and res ... | 2000 | 10966419 |
| synthesis, accumulation and hydrolysis of trehalose during growth of peanut rhizobia in hyperosmotic media. | we examined and compared the activities of synthetic and hydrolytic enzymes involved in trehalose metabolism, in three peanut rhizobia strains grown in control, hypersaline, and non-ionic hyperosmotic media. results indicated that the effects of hyperosmolarity on the synthesis and the degradation of the disaccharide were diverse. in the salt-tolerant slow-growing strain bradyrhizobium sp. atcc 10317, we observed increased synthesis and accumulation of trehalose under hyperosmolarity imposed by ... | 2000 | 10957956 |
| inoculation and nitrate alter phytohormone levels in soybean roots: differences between a supernodulating mutant and the wild type. | the levels of different cytokinins, indole-3-acetic acid (iaa) and abscisic acid (aba) in roots of glycine max [l.] merr. cv. bragg and its supernodulating mutant nts382 were compared for the first time. forty-eight hours after inoculation with bradyrhizobium, quantitative and qualitative differences were found in the root's endogenous hormone status between cultivar bragg and the mutant nts382. the six quantified cytokinins, ranking similarly in each genotype, were present at higher concentrati ... | 2000 | 10923709 |
| altered cell surface hydrophobicity of lipopolysaccharide-deficient mutant of bradyrhizobium japonicum. | the authors previously isolated a lipopolysaccharide (lps) deficient tn5-mutant of bradyrhizobium japonicum, and subsequently isolated the lps gene region. in this study the lps deficiency of b. japonicum was studied in terms of its cell surface characteristics. by monitoring the kinetics of the partition with hexadecane the lps-mutant was found to be far more hydrophobic than the wild type strain; the partition coefficients were 3.19 min(-1) for the mutant, as compared with only 1.40 min(-1) fo ... | 2000 | 10958967 |
| molecular characterization of a gene region involved in lipopolysaccharide biosynthesis in bradyrhizobium japonicum: cloning, sequencing and expression of rfaf gene. | a 3.0-kb region involved in lipopolysaccharide biosynthesis in bradyrhizobium japonicum was sequenced. one complete open reading frame was identified which encodes a polypeptide of 354 amino acid residues with a predicted molecular mass of 38 209 da. expression of the protein using a t7 gene expression system revealed a band of similar molecular mass after sodium dodecyl sulfate polyacrylamide gel electrophoresis. a database search against known gene sequences revealed a significant sequence sim ... | 2000 | 10981699 |
| erratum to: "stimulation of adhesiveness, infectivity, and competitiveness for nodulation of bradyrhizobium japonicum by its pretreatment with soybean seed lectin". | | 2000 | 11004414 |
| sinorhizobium fredii usda257, a cultivar-specific soybean symbiont, carries two copies of y4ya and y4yb, two open reading frames that are located in a region that encodes the type iii protein secretion system. | sinorhizobium fredii usda257 forms nitrogen-fixing nodules on primitive soybean (glycine max) cultivar peking but fails to nodulate the improved cultivar mccall. cultivar specificity is governed by a plasmid-borne locus, nolxbtuv. by dna sequence analysis, we have identified two open reading frames, y4ya and y4yb, immediately downstream of nolx. northern (rna) blot analysis indicated that the expression of both y4ya and y4yb is inducible by isoflavonoids, and an intact copy of nolx is required. ... | 2000 | 10975657 |
| differential expression of two soybean apyrases, one of which is an early nodulin. | two cdna clones were isolated from soybean (glycine soja) by polymerase chain reaction with primers designed to conserved motifs found in apyrases (nucleotide phosphohydrolase). the two cdnas are predicted to encode for two, distinct, apyrase proteins of approximately 50 kda (i.e., gs50) and 52 kda (i.e., gs52). phylogenetic analysis indicated that gs52 is orthologous to a family of apyrases recently suggested to play a role in legume nodulation. gs50 is paralogous to this family and, therefore, ... | 2000 | 11043467 |
| characterization and expression analysis of the yellow lupin (lupinus luteus l.) gene coding for nodule specific proline-rich protein. | the llprp2 gene coding for a proline-rich protein shows a high level of similarity to, as well as significant differences from the family of enod2 nodule-specific genes. several sequence motifs with putative regulatory function were identified in the 5' and 3' noncoding regions of the llprp2 gene. northern blot analysis revealed that the expression of the llprp2 gene begins 9 days after inoculation of yellow lupin roots with bradyrhizobium sp. (lupinus); the expression is restricted to symbiotic ... | 2000 | 11051202 |
| chaperone activity and homo- and hetero-oligomer formation of bacterial small heat shock proteins. | rhizobia are the only bacteria known to induce a multitude of small heat shock proteins (shsps) upon temperature upshift. the shsps of bradyrhizobium japonicum fall into two different classes, class a and class b. here, we studied the chaperone activity and oligomeric features of two representative members of each class. the purified shsps were efficient chaperones, as demonstrated by their ability to prevent thermally induced aggregation of citrate synthase in vitro. homo-oligomer formation of ... | 2000 | 10978322 |
| changes in the physiological and agricultural characteristics of peat-based bradyrhizobium japonicum inoculants after long-term storage. | commercial soybean inoculants processed with sterilised peat and stored at 20 degrees c for 1-8 years were used as experimental materials to assess the changes in the physiological activity of bradyrhizobium japonicum after storage. viable counts decreased and physiological characteristics of the bacterium changed during storage, with an increase in the time taken for colony appearance on a medium without yeast extract, an increase in the lag time for nodule appearance on soybean grown in glass ... | 2000 | 10968634 |
| [improvement of nitrogen fixation efficiency and plasmid stability in bradyrhizobium japonicum by the introduction of dctabd and parcba/de genes]. | a recombinant plasmid phn207 containing c4-dicarboxylic acid transport genes (dctabd) from sinorhizobium meliloti, parcba/de genes from ptr102 and reporter genes luxab from pdb30 was constructed by using plafr3 as the vector. the phn207 was then introduced into the bradyrhizobium japonicum ta11 and cb1809 by bi-parental mating. it was confirmed that parcba/de genes could increase the stability of plafr3 in the transconjugants under both free-living and symbiotic condition. the results of plant p ... | 2000 | 11055128 |
| an imperfect inverted repeat is critical for dna binding of the response regulator regr of bradyrhizobium japonicum. | regr is the response regulator of the regsr two-component regulatory system in bradyrhizobium japonicum. the only target known so far is the fixr-nifa operon, encoding the redox-responsive transcription factor nifa, which activates many genes required for symbiotic nitrogen fixation in soybean nodules. in previous in vivo studies, we identified a 32 bp upstream activating sequence located around position -68, which is essential for regr-dependent expression of the fixr-nifa operon. here, we used ... | 2000 | 11058113 |
| generation of new hydrogen-recycling rhizobiaceae strains by introduction of a novel hup minitransposon. | hydrogen evolution by nitrogenase is a source of inefficiency for the nitrogen fixation process by the rhizobium-legume symbiosis. to develop a strategy to generate rhizobial strains with h(2)-recycling ability, we have constructed a tn5 derivative minitransposon (tnhb100) that contains the ca. 18-kb h(2) uptake (hup) gene cluster from rhizobium leguminosarum bv. viciae upm791. bacteroids from tnhb100-containing strains of r. leguminosarum bv. viciae pre, bradyrhizobium japonicum, r. etli, and m ... | 2000 | 11010872 |
| bradyrhizobium sp. strains that nodulate the leguminous tree acacia albida produce fucosylated and partially sulfated nod factors. | we determined the structures of nod factors produced by six different bradyrhizobium sp. strains nodulating the legume tree acacia albida (syn. faidherbia albida). compounds from all strains were found to be similar, i.e., o-carbamoylated and substituted by an often sulfated methyl fucose and different from compounds produced by rhizobium-mesorhizobium-sinorhizobium strains nodulating other species of the acaciae tribe. | 2000 | 11055966 |
| localization of a nod factor-binding protein in legume roots and factors influencing its distribution and expression. | the roots of the legume dolichos biflorus contain a lectin/nucleotide phosphohydrolase (db-lnp) that binds to the nod factor signals produced by rhizobia that nodulate this plant. in this study we show that db-lnp is differentially distributed along the surface of the root axis in a pattern that correlates with the zone of nodulation of the root. db-lnp is present on the surface of young and emerging root hairs and redistributes to the tips of the root hairs in response to treatment of the roots ... | 2000 | 11080281 |
| genetic characterization of soybean rhizobia in paraguay. | the soybean is an exotic plant introduced in paraguay in this century; commercial cropping expanded after the 1970s. inoculation is practiced in just 15 to 20% of the cropping areas, but root nodulation occurs in most sites where soybeans grow. little is known about rhizobial diversity in south america, and no study has been performed in paraguay until this time. therefore, in this study, the molecular characterization of 78 rhizobial isolates from soybean root nodules, collected under field con ... | 2000 | 11055970 |
| photosynthetic bradyrhizobia are natural endophytes of the african wild rice oryza breviligulata. | we investigated the presence of endophytic rhizobia within the roots of the wetland wild rice oryza breviligulata, which is the ancestor of the african cultivated rice oryza glaberrima. this primitive rice species grows in the same wetland sites as aeschynomene sensitiva, an aquatic stem-nodulated legume associated with photosynthetic strains of bradyrhizobium. twenty endophytic and aquatic isolates were obtained at three different sites in west africa (senegal and guinea) from nodal roots of o. ... | 2000 | 11097925 |
| the bradyrhizobium japonicum proline biosynthesis gene proc is essential for symbiosis. | plant host-derived proline is proposed to serve as an energy source for rhizobia in the rhizosphere and in symbiotic root nodules. the bradyrhizobium japonicum proc gene was isolated, and a proc mutant strain that behaved as a strict proline auxotroph in culture was constructed. the proc strain elicited undeveloped nodules on soybeans that lacked nitrogen fixation activity and plant hemoglobin. we conclude that the proc gene is essential for symbiosis and suggest that the mutant does not obtain ... | 2000 | 11097929 |
| restriction fragment length polymorphism analysis of 16s rdna and low molecular weight rna profiling of rhizobial isolates from shrubby legumes endemic to the canary islands. | thirty-six strains of slow-growing rhizobia isolated from nodules of four woody legumes endemic to the canary islands were characterised by 16s rdna pcr-rflp analyses (ardra) and lmw rna profiling, and compared with reference strains representing bradyrhizobium japonicum, b. elkanii, b. liaoningense, and two unclassified bradyrhizobium sp. (lupinus) strains. both techniques showed similar results, indicating the existence of three genotypes among the canarian isolates. analysis of the combined r ... | 2000 | 11108022 |
| interspecies complementation of escherichia coli ccm mutants: ccme (cycj) from bradyrhizobium japonicum acts as a heme chaperone during cytochrome c maturation. | biogenesis of c-type cytochromes in alpha- and gamma-proteobacteria requires the function of a set of orthologous genes (ccm genes) that encode specific maturation factors. the escherichia coli ccme protein is a periplasmic heme chaperone. the membrane protein ccmc is required for loading ccme with heme. by expressing ccme (cycj) from bradyrhizobium japonicum in e. coli we demonstrated that heme is bound covalently to this protein at a strictly conserved histidine residue. the b. japonicum homol ... | 2000 | 11073932 |
| divergent mechanisms of 5' 23s rrna ivs processing in the alpha-proteobacteria. | widespread occurrence of a separate small rna derived from the 5'-end of 23s rrna and of an intervening sequence (ivs) which separates this domain from the main segment of 23s rrna in the alpha-proteobacteria implies that processing reactions which act to excise the ivs are also maintained in this group. we previously characterized the first example of processing of this ivs in rhodopseudomonas palustris, which is classified with the bradyrhizobia in this case, ivs excision occurs by a multistep ... | 2000 | 11095671 |
| variability in plant-microbe interaction between lupinus lines and bradyrhizobium strains. | even though lupin (lupinus albus l.) is known to potentially fix 150-200 kg/ha nitrogen for the use of a succeeding crop, precise information about lupinxbradyrhizobium strain interaction under the climatic conditions prevalent in the mid-atlantic region of the united states is unknown. we conducted two greenhouse experiments with the objective of characterizing this symbiotic relationship and to evaluate potential interaction between bradyrhizobium strains and lupin lines. in the first experime ... | 2000 | 11074278 |
| effect of bradyrhizobium photosynthesis on stem nodulation of aeschynomene sensitiva. | some leguminous species of the genus aeschynomene are specifically stem-nodulated by photosynthetic bradyrhizobia. to study the effect of bacterial photosynthesis during symbiosis, we generated a photosynthesis-negative mutant of the bradyrhizobium sp. strain ors278 symbiont of aeschynomene sensitiva. the presence of a functional photosynthetic unit in bacteroids and the high expression of the photosynthetic genes observed in stem nodules demonstrate that the bacteria are photosynthetically acti ... | 2000 | 11114184 |
| small-subunit rrna genotyping of rhizobia nodulating australian acacia spp. | the structure of rhizobial communities nodulating acacia in southeastern australia from south queensland to tasmania was investigated by a molecular approach. a total of 118 isolates from nodule samples from 13 different acacia species collected at 44 sites were characterized by small-subunit (ssu) ribosomal dna (rdna) pcr-restriction fragment length polymorphism analysis. nine rhizobial genomospecies were identified, and these taxa corresponded to previously described genomospecies (b. lafay an ... | 2001 | 11133471 |
| differential response of soybean (glycine max (l.) merr.) genotypes to lipo-chito-oligosaccharide nod bj v (c(18:1) mefuc). | lipo-chito-oligosaccharides (lcos) are bacteria-to-plant signal molecules essential for the establishment of rhizobia-legume symbioses. lcos invoke a number of physiological changes in the host plants, such as root hair deformation, cortical cell division and ontogeny of complete nodule structures. the responses of five soybean cultivars to nod bj: v (c(18:1) mefuc) isolated from bradyrhizobium japonicum strain 532c were studied with a new technique. two distinct types of root hair deformation w ... | 2000 | 11141178 |
| methylotrophic methylobacterium bacteria nodulate and fix nitrogen in symbiosis with legumes. | rhizobia described so far belong to three distinct phylogenetic branches within the alpha-2 subclass of proteobacteria. here we report the discovery of a fourth rhizobial branch involving bacteria of the methylobacterium genus. rhizobia isolated from crotalaria legumes were assigned to a new species, "methylobacterium nodulans," within the methylobacterium genus on the basis of 16s ribosomal dna analyses. we demonstrated that these rhizobia facultatively grow on methanol, which is a characterist ... | 2001 | 11114919 |
| numerical taxonomy of sarothamnus scoparius rhizobia. | twenty nodule isolates from sarothamnus scoparius (broom) growing in poland and nine strains from plants growing in japan were studied for phenotypic properties, plasmid presence, phage sensitivity, and host plant specificity. by numerical analysis of phenotypic properties, it was found that the studied nodule bacteria, originating from geographically different countries, constitute two separate groups affiliated to the bradyrhizobium cluster. the membership of s. scoparius rhizobia in the brady ... | 2001 | 11116393 |
| synthesis of a low-molecular-weight form of exopolysaccharide by bradyrhizobium japonicum usda 110. | a novel extracellular low-molecular-weight polysaccharide was detected as a contaminant within extracellular cyclic beta-1,6-beta-1,3-glucan preparations from bradyrhizobium japonicum usda 110 cultures. compositional analysis, methylation analysis, and nuclear magnetic resonance analysis revealed that this low-molecular-weight polysaccharide was composed of the same pentasaccharide repeating unit previously described for the high-molecular-weight form of the exopolysaccharide (eps) synthesized b ... | 2001 | 11157281 |
| one of two hemn genes in bradyrhizobium japonicum is functional during anaerobic growth and in symbiosis. | previously, we screened the symbiotic gene region of the bradyrhizobium japonicum chromosome for new nifa-dependent genes by competitive dna-rna hybridization (a. nienaber, a. huber, m. göttfert, h. hennecke, and h. m. fischer, j. bacteriol. 182:1472-1480, 2000). here we report more details on one of the genes identified, a hemn-like gene (now called hemn(1)) whose product exhibits significant similarity to oxygen-independent coproporphyrinogen iii dehydrogenases involved in heme biosynthesis in ... | 2001 | 11157943 |
| potential symbiosis-specific genes uncovered by sequencing a 410-kilobase dna region of the bradyrhizobium japonicum chromosome. | the physical and genetic map of the bradyrhizobium japonicum chromosome revealed that nitrogen fixation and nodulation genes are clustered. because of the complex interactions between the bacterium and the plant, we expected this chromosomal sector to contain additional genes that are involved in the maintenance of an efficient symbiosis. therefore, we determined the nucleotide sequence of a 410-kb region. the overall g+c nucleotide content was 59.1%. using a minimum gene length of 150 nucleotid ... | 2001 | 11157954 |
| evidence for a functional similarity between the two-component regulatory systems regsr, actsr, and regba (prrba) in alpha-proteobacteria. | the symbiotic bacteria bradyrhizobium japonicum and sinorhizobium meliloti, and the purple photosynthetic bacteria rhodobacter capsulatus, rhodovulum sulfidophilum, roseobacter denitrificans and rhodobacter sphaeroides possess homologous two-component regulatory systems, namely regsr, actsr, regba and prrba. the respective response regulators of these bacteria control expression of different regulons that are involved in n2 fixation, co2 fixation, photosynthesis or acid tolerance. we therefore a ... | 2000 | 11131020 |
| evolutionary relationships among the soybean bradyrhizobia reconstructed from 16s rrna gene and internally transcribed spacer region sequence divergence. | from sequence divergence of 16s rrna genes and the internally transcribed spacer (its) region it is reported that variation in phylogenetic placement exists among the 17 different serotype strains of bradyrhizobium that have been isolated from nodules of soybean. evolutionary relationships among the bradyrhizobia were more resolved using reconstructions derived from its than from 16s rrna gene sequence divergence. strain usda 129 was placed together with usda 62, 110, 122 and 126, but did not cl ... | 2000 | 11155993 |
| characterization of the common nodulation genes of the photosynthetic bradyrhizobium sp. ors285 reveals the presence of a new insertion sequence upstream of noda. | we isolated and characterized noda genes from photosynthetic and non-photosynthetic rhizobia nodulating the legume genus aeschynomene, and found that the noda sequence from photosynthetic stem-nodulating bacteria was phylogenetically distant from the other already described noda genes. characterization of the photosynthetic strain ors285 common nod gene cluster (nodabc) showed, upstream of noda, the presence of a new insertion sequence element belonging to the is3 family and specific to a group ... | 2001 | 11150670 |
| phylogenetic and dna-dna hybridization analyses of bradyrhizobium species. | the 16s rdna sequence of bradyrhizobium liaoningense was determined and analysed together with sequences of other bradyrhizobium species and related taxa. in addition, dna-dna hybridizations were performed between representative strains of the three bradyrhizobium species. bradyrhizobium liaoningense is genotypically highly related to bradyrhizobium japonicum, whereas bradyrhizobium elkanii is more distantly related to these two species. the fact that afipia, agromonas, blastobacter, nitrobacter ... | 2001 | 11211247 |
| novel methylated triterpenoids of the gammacerane series from the nitrogen-fixing bacterium bradyrhizobium japonicum usda 110. | the nitrogen-fixing, symbiotic root-nodule forming bacterium bradyrhizobium japonicum usda 110 contained gammacerane derivatives next to triterpenoids of the hopane series. diploptene, diplopterol, 2 beta-methyldiplopterol, aminobacteriohopanetriol and adenosylhopane were accompanied by tetrahymanol and the corresponding novel methylated homologues 2 beta-methyltetrahymanol, 20 alpha-methyltetrahymanol, and 2 beta,20 alpha-dimethyltetrahymanol. incorporation of [(2)h(3)]methyl-l-methionine indic ... | 2001 | 11231284 |
| supply of o2 regulates demand for o2 and uptake of malate by n2-fixing bacteroids from soybean nodules. | bacteroids, prepared anaerobically from soybean root nodules by fractional centrifugation or by sucrose or percoll density-gradient methods, were retained within a stirred, flow-through reaction chamber and used to determine rates of respiration and n2 fixation at various rates of o2 supply. liquid reaction solutions containing malate, oxyleghaemoglobin, dissolved n2 and various levels of dissolved o2 were passed through the reaction chamber at measured rates of flow. the relative oxygenation of ... | 2001 | 11238973 |
| partial purification and characterization of pyruvate kinase from the plant fraction of soybean root nodules. | pyruvate kinase (pk, ec 2.7.1.40) was partially purified from the plant cytosolic fraction of n2-fixing soybean (glycine max [l.] merr.) root nodules. the partially purified pk preparation was completely free of contamination by phosphoenolpyruvate carboxylase (pepc, ec 4.1.1.31), the other major phosphoenolpyruvate (pep)-utilizing enzyme in legume root nodules. latency experiments with sonicated nodule extracts showed that bradyrhizobium japonicum bacteroids do not express either pk or pepc act ... | 2001 | 11240911 |
| molecular evidence for shifts in polysaccharide composition associated with adaptation of soybean bradyrhizobium strains to the brazilian cerrado soils. | pyrolysis mass spectrometry (pyms) and dna fingerprinting (rapd and rsalpha hybridization) were used to characterize soybean inoculant strains and root nodule isolates of bradyrhizobia from the brazilian cerrado soils. most isolates were shown to be derived from the inoculant strains on the basis of genotype comparisons by dna fingerprinting. phenotypic analysis (using pyms) of the strains and separately of the polysaccharides derived from them showed that the nodule isolates differed from the p ... | 1999 | 11207759 |
| genetic snapshots of the rhizobium species ngr234 genome. | in nitrate-poor soils, many leguminous plants form nitrogen-fixing symbioses with members of the bacterial family rhizobiaceae. we selected rhizobium sp. ngr234 for its exceptionally broad host range, which includes more than i 12 genera of legumes. unlike the genome of bradyrhizobium japonicum, which is composed of a single 8.7 mb chromosome, that of ngr234 is partitioned into three replicons: a chromosome of about 3.5 mb, a megaplasmid of more than 2 mb (pngr234b) and pngr234a, a 536,165 bp pl ... | 2000 | 11178268 |
| phosphatidylcholine levels in bradyrhizobium japonicum membranes are critical for an efficient symbiosis with the soybean host plant. | phosphatidylcholine (pc), the major membrane phospholipid in eukaryotes, is found in only some bacteria including members of the family rhizobiaceae. for this reason, it has long been speculated that rhizobial pc might be required for a successful interaction of rhizobia with their legume host plants in order to allow the formation of nitrogen-fixing root nodules. a major pathway for pc formation in prokaryotes involves a threefold methylation of the precursor phosphatidylethanolamine (pe). here ... | 2001 | 11251836 |
| [a study on taxonomy of rhizobia isolated from astragalus sp]. | thirty-six strains isolated from root nodule of astragalus spp., in comparison with 31 reference strains of rhizobium, bradyrhizobium and sinorhizobium species, and some other strains isolated from legumes in xinjiang and hainian province, were classified by performing numberical taxonomy, dna-dna hybrization and partial 16s rrna gene sequencing. results of herichical analysis showed most of trains isolated from astragalus spp. fell into subgroups 8 and 9, also the dna homolgy among strains of s ... | 1997 | 11189357 |
| an internal region of the rpoh heat shock transcription factor is critical for rapid degradation by the ftsh protease. | the proteolysis of regulatory proteins plays an important role in the control of gene expression. the escherichia coli heat shock sigma factor rpoh (sigma(32)) is highly unstable. its instability is determined by interactions with the dnak chaperone machine, rna polymerase and the atp-dependent protease ftsh. bradyrhizobium japonicum expresses three rpoh proteins of which rpoh(1) is highly stable. to determine which regions of e. coli rpoh determine protein lability, we generated a number of tru ... | 2001 | 11277997 |
| divergent bradyrhizobium symbionts on tachigali versicolor from barro colorado island, panama. | relationships of root-nodule bacteria from the tree tachigali versicolor (legume subfamily caesalpinioideae) were analyzed for 20 isolates sampled from juvenile plants growing on barro colorado island (bci), panama. bacterial genetic diversity appeared to be low. in the highly polymorphic 5' intervening sequence region of 23s rrna, all isolates had the same length variant. a 472 bp segment spanning this region was sequenced in four isolates, and all proved to be identical at every nucleotide pos ... | 2000 | 11249030 |
| classification of rhizobia based on nodc and nifh gene analysis reveals a close phylogenetic relationship among phaseolus vulgaris symbionts. | the nodc and nifh genes were characterized in a collection of 83 rhizobial strains which represented 23 recognized species distributed in the genera rhizobium, sinorhizobium, mesorhizobium and bradyrhizobium, as well as unclassified rhizobia from various host legumes. conserved primers were designed from available nucleotide sequences and were able to amplify nodc and nifh fragments of about 930 bp and 780 bp, respectively, from most of the strains investigated. rflp analysis of the pcr products ... | 2001 | 11283294 |
| evidence for direct interaction between enzyme i(ntr) and aspartokinase to regulate bacterial oligopeptide transport. | bradyrhizobium japonicum transports oligopeptides and the heme precursor delta-aminolevulinic acid (ala) by a common mechanism. two tn5-induced mutants disrupted in the lysc and ptsp genes were identified based on the inability to use prolyl-glycyl-glycine as a proline source and were defective in [(14)c]ala uptake activity. lysc and ptsp were shown to be proximal genes in the b. japonicum genome. however, rnase protection and in trans complementation analysis showed that lysc and ptsp are trans ... | 2001 | 11287431 |
| case of localized recombination in 23s rrna genes from divergent bradyrhizobium lineages associated with neotropical legumes. | enzyme electrophoresis and rrna sequencing were used to analyze relationships of bradyrhizobium sp. nodule bacteria from four papilionoid legumes (clitoria javitensis, erythrina costaricensis, rhynchosia pyramidalis, and desmodium axillare) growing on barro colorado island (bci), panama. bacteria with identical multilocus allele profiles were commonly found in association with two or more legume genera. among the 16 multilocus genotypes (electrophoretic types [ets]) detected, six ets formed a cl ... | 2001 | 11319084 |
| comparison of sequence analysis of 16s-23s rdna spacer regions, aflp analysis and dna-dna hybridizations in bradyrhizobium. | the sequences of the 16s-23s rdna intergenic spacer region of 62 strains of bradyrhizobium, including representatives of the three valid species, were determined. the majority of strains had a single rrna operon type and all contained a trna(ala) and a trna(ile) gene. analysis of the sequence data produced groupings in line with previously obtained aflp data. dna-dna hybridizations were performed to determine to what extent spacer sequences and aflp profiles reflected the overall genomic similar ... | 2001 | 11321108 |
| [effect of certain environmental factors on bradyrhizobium japonicum]. | dependence of motility and chemotaxis was studied in two strains of bradyrhizobium japonicum upon several environmental factors. in both strains, chemotaxis was found to increase with an increasing concentration of the attractant (glucose) to 5.6 x 10(-2) m. both motility and chemotaxis reached their maximum in the two- to three-day cultures at neutral ph. the maximum motility of these bacteria occurred at 40 degrees c. the maximum values of chemotaxis in these microorganisms were, however, obse ... | 2001 | 11338826 |
| genetic diversity of bradyrhizobium strains isolated from arachis hypogaea. | rhizobia are used exclusively in agricultural systems for enhancing the ability of legumes to fix atmospheric nitrogen. knowledge about the indigenous population is necessary for the selection and application of inoculant strains. in this study, we have assessed the genetic diversity of bradyrhizobium strains isolated from the host plant, arachis hypogaea along the coastline of tamil nadu. different populations collected from varying environmental conditions were analysed for salt and ph toleran ... | 2001 | 11261490 |
| ribotyping of rhizobia nodulating acacia mangium and paraserianthes falcataria from different geographical areas in indonesia using pcr-rflp-sscp (prs) and sequencing. | acacia mangium and paraserianthes falcataria are leguminous tree species widely grown for timber in indonesia and other tropical countries, yet little is known about the identity of their rhizobial symbionts. polymerase chain reaction-restriction fragment length polymorphism-single-strand conformational polymorphism (prs) analysis of the 16s rrna gene was used along with sequencing to assess the diversity of 57 rhizobia isolated from nodules of a. mangium and p. falctaria in indonesia. in total, ... | 2001 | 11359513 |
| [effect of heavy metals and reclaimers on formation and functioning of legume-rhizobium symbiosis]. | the influence of a mixture of salts of heavy metals cd2+, cu2+, pb2+, zn2+ on the efficiency of legume-rhizobial symbiosis and a part of reclaimers in the decrease of toxic effect of pollutants have been studied under conditions of the vegetative and field experiment on small plots. concentrations of salts of heavy metals were tested in the interval of 1 to 20 mpc (maximum permissible concentrations). negative effect of the tested substances on the growth, photo-assimilation properties of soybea ... | 2000 | 11247350 |
| sugar-binding activity of pea lectin enhances heterologous infection of transgenic alfalfa plants by rhizobium leguminosarum biovar viciae. | transgenic alfalfa (medicago sativa l. cv regen) roots carrying genes encoding soybean lectin or pea (pisum sativum) seed lectin (psl) were inoculated with bradyrhizobium japonicum or rhizobium leguminosarum bv viciae, respectively, and their responses were compared with those of comparably inoculated control plants. we found that nodule-like structures formed on alfalfa roots only when the rhizobial strains produced nod factor from the alfalfa-nodulating strain, sinorhizobium meliloti. uninfect ... | 2001 | 11351077 |
| the interaction of protozoa with their potential prey bacteria in the rhizosphere. | extensive colonization of the rhizosphere by beneficial bacteria is desirable but it is not yet clear whether the feeding patterns of protozoa exert any ecological impact on the competence of bacteria in the rhizosphere. to determine whether the successful colonization of the rhizosphere by bacteria can be explained by inherent abilities of the bacteria to resist predation, six bacteria categorized as poor, mediocre or good rhizosphere colonists were tested. the populations of protozoa in the rh ... | 2001 | 11411840 |
| tolerance of bradyrhizobium sp. (lupini) strains to salinity, ph, caco3 and antibiotics. | ten rhizobial isolates obtained from different locations in egypt were examined for their ability to survive under stress conditions and their growth response to increasing levels of nacl (1-8% w/v), ph (4-10), caco3 (1-10% w/v) and 12 antibiotics. | 2001 | 11412347 |
| trehalose becomes the most abundant non-structural carbohydrate during senescence of soybean nodules. | carbohydrate metabolism and symbiont survival were studied in nodules of soybean (g. max [l.] merr. cv. maple arrow infected with bradyrhizobium japonicum 61-a-101), induced to senesce simultaneously by application of the photosynthesis inhibitor dichloromethyl urea (dcmu). the plant-borne carbohydrates sucrose and starch started to decline after 2 d and reached background levels after 8 d, in parallel with the decline of nitrogenase. however, the microsymbiont-borne disaccharide trehalose decli ... | 2001 | 11432911 |
| the essential hupb and hupn proteins of pseudomonas putida provide redundant and nonspecific dna-bending functions. | a protein mixture containing two major components able to catalyze a beta-recombination reaction requiring nonspecific dna bending was obtained by fractionation of a pseudomonas putida extract. n-terminal sequence analysis and genomic data base searches identified the major component as an analogue of hupb of pseudomonas aeruginosa and escherichia coli, encoding one hu protein variant. the minor component of the fraction, termed hupn, was divergent enough from hupb to predict a separate dna-bend ... | 2001 | 11278879 |
| frankia kb5 possesses a hydrogenase immunologically related to membrane-bound. | the immunological relationship of the hydrogenase in frankia kb5 to hydrogenases in other microorganisms was investigated using antisera raised against holo-[nife]-hydrogenases isolated from alcaligenes latus, azotobacter vinelandii, ralstonia eutropha, and the small and large hydrogenase subunits from bradyrhizobium japonicum. the antisera raised against the a. latus, r. eutropha, and b. japonicum (large subunit) polypeptides were found to recognize two polypeptides, corresponding to the unproc ... | 2001 | 11381338 |
| changes in fatty acid composition and degree of unsaturation of (brady)rhizobia as a response to phases of growth, reduced water activities and mild desiccation. | the effects of growth phase, reductions in the water activity (a(w)) of the growth medium and mild desiccation on the composition and the degree of unsaturation of cellular fatty acids (cfa) of sinorhizobium meliloti, bradyrhizobium elkanii and bradyrhizobium japonicum were studied. during the course of growth, an interchange of cis-vaccenic with lactobacillic acid and a slight increase in palmitic acid were observed while other fatty acids remained constant. the degree of unsaturation was signi ... | 2001 | 11392487 |