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aerobic growth and respiration of a delta-aminolevulinic acid synthase (hema) mutant of bradyrhizobium japonicum.oxygen-dependent growth of the bradyrhizobium japonicum hema mutant mlg1 (m.l. guerinot and b.k. chelm, proc. natl. acad. sci. usa 83:1837-1841, 1986) was demonstrated in cultured cells in the absence of exogenous delta-aminolevulinic acid (ala), but growth of analogous mutants of rhizobium meliloti or of escherichia coli was not observed unless ala was added to the yeast extract-containing media. no heme could be detected in extracts of strain mlg1 cells as measured by the absorption or by the ...19911846857
purification and properties of malonyl-coa synthetase from rhizobium japonicum.a novel malonyl-coa synthetase was found in rhizobium japonicum bacteroid of the soybean nodule. the levels of the enzyme in the free-living cells grown on a variety of carbon sources including glucose were similar, indicating that this enzyme is not inducible. the malonyl-coa synthetase from glucose-grown rhizobium japonicum was purified to homogeneity. the mr of the enzyme was determined to be 58,000 by gel filtration on a sephacryl s-300 and by sds/page respectively, indicating a single polyp ...19911847615
discovery and sequence analysis of bacterial genes involved in the biogenesis of c-type cytochromes.we report the dna sequence and mutational analysis of a novel cluster of six bradyrhizobium japonicum genes of which at least three (designated cycv, cycw, and cycx) are essential for the formation of all cellular c-type cytochromes. mutants having insertions in these genes were completely devoid of any soluble (periplasmic) or membrane-bound c-type cytochromes; even the apo form of cytochrome c1 was not detectable, neither in the membrane nor in the soluble fraction. as a consequence, the mutan ...19911850420
oxygen-dependent catabolism of indole-3-acetic acid in bradyrhizobium japonicum.some strains of bradyrhizobium japonicum have the ability to catabolize indole-3-acetic acid (iaa). examination of this catabolism in strain 110 by in vivo experiments has revealed an enzymatic activity catalyzing the degradation of iaa and 5-hydroxy-indole-3-acetic acid. the activity requires addition of the substrates for induction and is oxygen dependent. the highest activity is obtained when the concentration of inducer is 0.2 mm. spectrophotometric data are consistent with the suggestion th ...19911856182
cloning, sequencing, and mutational analysis of the bradyrhizobium japonicum fumc-like gene: evidence for the existence of two different fumarases.the bradyrhizobium japonicum fumarase gene (fumc-like) was cloned and sequenced, and a fumc deletion mutant was constructed. this mutant had a nod+ fix+ phenotype in symbiosis with the host plant, soybean, and growth in minimal medium with fumarate as sole carbon source was also not affected. the cloned b. japonicum fumc gene fully complemented an escherichia coli fum- mutant, strain jh400, for growth in minimal medium with fumarate. the predicted amino acid sequence of the fumc protein showed s ...19911856685
chemical control of interstrain competition for soybean nodulation by bradyrhizobium japonicum.previous research has shown that a significant limitation to the agricultural use of improved rhizobial inoculant strains is competition from the indigenous soil population. in this work, we sought to test whether chemical inhibitors of flavonoid-induced nod gene expression in bradyrhizobium japonicum could be identified and utilized to affect interstrain competition for nodulation of soybeans. approximately 1,000 structural and functional analogs of the known, natural inducers of nod gene expre ...19911892378
rapid and sensitive assay for the phytotoxin rhizobitoxine.rhizobitoxine is a phytotoxin synthesized by some strains of the legume symbiont genus bradyrhizobium and the plant pathogen pseudomonas andropogonis. we demonstrate here a new enzymatic assay which is 100-fold more sensitive than previous assays and can detect as little as 1.0 pmol of rhizobitoxine. the assay is based on the inhibition of salmonella typhimurium beta-cystathionase by rhizobitoxine. interestingly, beta-cystathionase from bradyrhizobium japonicum is insensitive to rhizobitoxine at ...19911892399
isolation of bradyrhizobium japonicum dna sequences that are transcribed at high levels in bacteroids.dna sequences have been isolated that are expressed at high levels in bacteroids, the differentiated form of the soybean microsymbiont, bradyrhizobium japonicum. random-primed cdna was synthesized using total rna isolated from purified b. japonicum bacteroids or from cells grown in culture. when used directly to screen bacteriophage lambda libraries, these cdna probes produced a high background hybridization signal due to sequence similarity between b. japonicum and e. coli ribosomal dna (rdna) ...19911896009
elevated levels of stress proteins associated with bacterial symbiosis in amoeba proteus and soybean root nodule cells.obligatory bacterial endosymbionts of amoeba proteus and symbiotic bradyrhizobium japonicum bacteroids in soybean-root nodules contained large amounts of 67-kda and 65-kda proteins, respectively, antigenically related to groel of e. coli and the 58-kda heat-shock protein of tetrahymena. monoclonal antibodies against the 67-kda protein recognized groel analogs from several different organisms. the quantity of the stress protein in symbiotic b. japonicum bacteroids was augmented seven times that i ...19911912387
bradyrhizobium japonicum nodd1 can be specifically induced by soybean flavonoids that do not induce the nodyabcsuij operon.besides genistein and daidzein, which are active inducers of the nodyabcsuij operon in bradyrhizobium japonicum, soybean seeds also excrete compounds that are not inducers of the nodyabcsuij genes but enhance induction of this operon in the presence of a suboptimal genistein concentration. this synergism was studied in detail, and specific compounds were identified in seed exudate which specifically induce the nodd1 gene but not the nodyabcsuij operon. therefore, our current hypothesis is that t ...19921730597
nucleotide sequences of membrane-bound hydrogenase gene in alcaligenes hydrogenophilus.the nucleotide sequences of membrane-bound hydrogenase small (hups) and large (hupl) subunit genes of hydrogen bacterium alcaligenes hydrogenophilus were determined. the hups and hupl genes encoded polypeptides of 363 and 619 amino acids, respectively. the hups was located upstream of hupl with 35bp of intergenic region. the consensus ribosome-binding sequences were identified upstream of the start codons of hups and hupl. amino acid sequence of hups is very similar to that of rhodobacter capsul ...19921294332
isolation and characterization of rhizobitoxine mutants of bradyrhizobium japonicum.to explore the role of rhizobitoxine in bradyrhizobium-legume symbiosis, 11 rhizobitoxine mutants of b. japonicum usda61 were isolated on the basis of their inability to synthesize the toxin in culture. each mutant is prototrophic and symbiotically effective on soybean, cowpea, siratro, and glycine soja. the rhizobitoxine mutants differ in their chlorosis phenotypes and rhizobitoxine production in planta. as expected, one group of mutant fail to make toxin in planta, resulting in the absence of ...19921317377
dissociation by nh4cl treatment of the enzymic activities of glutamine synthetase ii from rhizobium leguminosarum biovar viceae.glutamine synthetase ii (gsii) was purified to homogeneity from rhizobium leguminosarum biovar viceae and characterized. the sequence of 26 amino acid residues from the amino-terminal end of the protein showed high similarity with the sequence of gsii from bradyrhizobium japonicum or from rhizobium meliloti. non-denaturing page showed that gsii, either in crude extracts or in the pure state, was a mixture of an octamer and a tetramer and that under specific conditions the octamer/tetramer ratio ...19921355107
phylogeny of fast-growing soybean-nodulating rhizobia support synonymy of sinorhizobium and rhizobium and assignment to rhizobium fredii.we determined the sequences for a 260-base segment amplified by the polymerase chain reaction (corresponding to positions 44 to 337 in the escherichia coli 16s rrna sequence) from seven strains of fast-growing soybean-nodulating rhizobia (including the type strains of rhizobium fredii chemovar fredii, rhizobium fredii chemovar siensis, sinorhizobium fredii, and sinorhizobium xinjiangensis) and broad-host-range rhizobium sp. strain ngr 234. these sequences were compared with the corresponding pre ...19921371066
identification and cloning of bradyrhizobium japonicum genes expressed strain selectively in soil and rhizosphere.the growth of bradyrhizobium japonicum usda 110 and usda 438 in soil extract-supplemented medium led to transcription of a large amount of dna not expressed in basal medium. strain usda 438 was more competitive for the nodulation of soybean than strain usda 110. to identify and isolate dna regions which were expressed specifically in strain usda 438 but not in strain usda 110 in response to soil extract or soybean root exudate, we developed a subtractive rna hybridization procedure. several cosm ...19921377899
evidence for a close genealogical relationship between afipia (the causal organism of cat scratch disease), bradyrhizobium japonicum and blastobacter denitrificans.the primary structures of the small subunit rrna of bradyrhizobium japonicum and blastobacter denitrificans were determined by direct sequencing of enzymatically amplified dna. comparative sequence analysis revealed that bradyrhizobium japonicum and blastobacter denitrificans are members of the alpha-2 subgroup of the proteobacteria and show a very close phylogenetic relationship with the genus afipia.19921383084
incorporation of a bacterial membrane-bound hydrogenase into proteoliposomes.membrane-bound nickel-iron hydrogenases from diverse genera of bacteria have been previously characterized and they are closely related. we report the reconstitution of purified bradyrhizobium japonicum hydrogenase into proteoliposomes by a detergent dialysis method followed by two or three cycles of freeze-thaw. sedimentation experiments revealed that more than 60% of the h2-uptake activity was particulate when reconstituted into escherichia coli phospholipids. sucrose-gradient centrifugation s ...19921384385
a succinate transport mutant of bradyrhizobium japonicum forms ineffective nodules on soybeans.biochemical evidence has shown that dicarboxylic acids actively support symbiotic nitrogen fixation by both fast- and slow-growing rhizobium. mutants defective in the active uptake of succinate have been previously described only in species of the fast-growing rhizobium. this article is a report on the isolation of mutants defective in dicarboxylate transport in a slow-growing species of rhizobium, bradyrhizobium japonicum. one of these presumptive dicarboxylate transport mutants, gts, was chara ...19921393826
structures of the oligosaccharides obtained from the core regions of the lipopolysaccharides of bradyrhizobium japonicum 61a101c and its symbiotically defective lipopolysaccharide mutant, js314.the only core oligosaccharide released from the lipopolysaccharide (lps) of bradyrhizobium japonicum 61a101c by prolonged (5 h) mild hydrolysis with acid, and the major core oligosaccharide obtained from its symbiotic and lps-defective mutant, js314, was the trisaccharide alpha-d-man p-(1----4)-alpha-d-glc p-(1----4)-2,7-anhydro-alpha-kdof. the 2,7-anhydro-3-deoxy-alpha-d-manno-2- octulofuranosonic acid moiety was probably formed during the prolonged mild hydrolysis with acid. a disaccharide cor ...19921394315
role of integration host factor in stimulating transcription from the sigma 54-dependent nifh promoter.in a wide variety of nitrogen-fixing organisms among the purple bacteria (large division of gram-negative bacteria) the nitrogen fixation (nif) operons are transcribed by an alternative holoenzyme form of rna polymerase, sigma 54-holoenzyme. transcription depends on the activator protein nifa (nitrogen fixation protein a), which catalyzes isomerization of closed complexes between this polymerase and a promoter to transcriptionally productive open complexes. nifa-mediated activation of transcript ...19921404379
isolation and characterization of an ndvb locus from rhizobium fredii.a gene (ndvb) in rhizobium meliloti that is essential for nodule development in medicago sativa (alfalfa), specifies synthesis of a large membrane protein. this protein appears to be an intermediate in beta-1,2-glucan synthesis by the microsymbiont. southern hybridization analysis showed strong homology between an ndvb (chvb) probe and genomic dna of r. fredii but not from bradyrhizobium japonicum. a cosmid clone containing the putative ndvb locus was isolated from a rhizobium fredii gene librar ...19921406255
structural and functional analysis of two different nodd genes in bradyrhizobium japonicum usda110.bradyrhizobium japonicum has two closely linked homologs of the nodulation regulatory gene, nodd; these homologs are located upstream of and in divergent orientation to the nodyabcsuij gene cluster. we report here the nucleotide sequence and mutational analyses of both nodd copies. the predicted nodd1 and nodd2 proteins shared 62% identical amino acid residues at corresponding positions and exhibited different degrees of homology with nodd proteins of other bradyrhizobium, azorhizobium, and rhiz ...19921421512
genetic relatedness of bradyrhizobium japonicum field isolates as revealed by repeated sequences and various other characteristics.forty-nine isolates of bradyrhizobium japonicum indigenous to a field where soybeans were grown for 45 years without inoculation were characterized by using four dna hybridization probes from b. japonicum. nifdk-specific hybridization clearly divided the isolates into two divergent groups. diversity in repeated-sequence (rs)-specific hybridization was observed; 44 isolates derived from 41 nodules were divided into 33 different rs fingerprint groups. cluster analysis showed that the rs fingerprin ...19921444394
genes for a second terminal oxidase in bradyrhizobium japonicum.bradyrhizobium japonicum possesses a mitochondria-like respiratory chain terminating with an aa3-type cytochrome c oxidase. the gene for subunit i of this enzyme (coxa) had been identified and cloned previously via heterologous hybridization using a paracoccus denitrificans dna probe. in the course of these studies, another b. japonicum dna region was discovered which apparently encoded a second terminal oxidase that was different from cytochrome aa3 but also belonged to the superfamily of heme/ ...19921444719
differential expression of nods accounts for the varied abilities of rhizobium fredii usda257 and rhizobium sp. strain ngr234 to nodulate leucaena spp.transfer of a cosmid containing nodsu from rhizobium sp. ngr234 to rhizobium fredii usda257 expands the host range for nodulation to include the perennial tropical legumes, leucaena leucocephala and leucaena diversifolia. complementation experiments with a series of subclones established that nods and its associated nod-box promoter from ngr234 are sufficient to confer this extended host-range phenotype to l. leucocephala. strain usda257 contains its own copy of nodsu, including upstream nod-box ...19921484488
nickel-dependent reconstitution of hydrogenase apoprotein in bradyrhizobium japonicum hupc mutants and direct evidence for a nickel metabolism locus involved in nickel incorporation into the enzyme.a double mutant (jh103k10) was created from hydrogenase constitutive mutant (jh103) by replacement of a chromosomal 0.60 kb nickel metabolism related locus with a kanamycin resistance gene. the double mutant required 10 to 20 times more nickel (ni) to achieve near parental strain levels of hydrogenase activity. in the absence of nickel, both jh103k10 and jh103 synthesized high levels of (inactive) hydrogenase apoprotein (large subunit, 65 kda). with nickel, the double mutant jh103k10 synthesized ...19921503531
similarities between legume-rhizobium communication and steroid-mediated intercellular communication in vertebrates.regulation of the actions of flavonoids and nod factors in legume-rhizobia communication has several interesting similarities with that of steroid-mediated actions in vertebrates. oxidation or reduction of flavonoids and nod factors modifies their biological activity just as, for example, oxidation of an alcohol at c11 on hydrocortisone regulates its biological activity. second, some flavonoids are anti-inducers, functioning like steroid antagonists to negate the actions of inducer flavonoids. a ...19921504919
analysis of dna sequences transcribed at high levels in bradyrhizobium japonicum bacteroids but not necessary for symbiotic effectiveness.five regions of the bradyrhizobium japonicum genome, which are transcribed at high levels in nitrogen-fixing soybean (glycine max) nodules, were identified. none of these regions contained previously identified genes (e.g., nif, nod, and fix genes) that are known to be essential for development of functional nitrogen-fixing nodules. to assess the role of these regions in the development of the b. japonicum-soybean symbiosis, we cloned and used them to construct b. japonicum strains, in which lar ...19921515666
a 2-o-methylfucose moiety is present in the lipo-oligosaccharide nodulation signal of bradyrhizobium japonicum.bradyrhizobium japonicum is a soil bacterium that forms nitrogen-fixing nodules on the roots of the agronomically important legume soybean. microscopic observation of plant roots showed that butanol extract of b. japonicum strain usda110 cultures induced for nod gene expression elicited root hair deformation, an early event in the nodulation process. the metabolite produced by b. japonicum responsible for root hair deformation activity was purified. chemical analysis of the compound revealed it ...19921528893
characterization of a fixlj-regulated bradyrhizobium japonicum gene sharing similarity with the escherichia coli fnr and rhizobium meliloti fixk genes.we describe the cloning, sequencing, regulation, and mutational analysis of a bradyrhizobium japonicum fixk-like gene whose product belongs to the family of fnr-crp-related regulatory proteins. the predicted 237-amino-acid fixk protein was found to share between 28 and 38% sequence identity with the escherichia coli fnr protein, other bacterial fnr-like proteins (fnrn, anr, and hlyx), and two rhizobial fixk proteins. the b. japonicum fixk-like gene, when expressed from a lac promoter, could func ...19921551834
functional analysis of the cysteine motifs in the ferredoxin-like protein fdxn of rhizobium meliloti involved in symbiotic nitrogen fixation.the rhizobium meliloti fdxn gene, which is part of the nifa-nifb-fdxn operon, is absolutely required for symbiotic nitrogen fixation. the deduced sequence of the fdxn protein is characterized by two cysteine motifs typical of bacterial-type ferredoxins. the fix-phenotype of an r. meliloti fdxn::[tc] mutant could be rescued by the r. leguminosarum fdxn gene, whereas no complementation was observed with nif-associated genes encoding ferredoxins from bradyrhizobium japonicum, azotobacter vinelandii ...19921603075
isoliquiritigenin, a strong nod gene- and glyceollin resistance-inducing flavonoid from soybean root exudate.isoflavonoid signal molecules from soybean (glycine max (l.) merr.) seed and root exudate induce the transcription of nodulation (nod) genes in bradyrhizobium japonicum. in this study, a new compound with symbiotic activity was isolated from soybean root exudate. the isolated 2',4',4-trihydroxychalcone (isoliquiritigenin) is characterized by its strong inducing activity for the nod genes of b. japonicum. these genes are already induced at concentrations 1 order of magnitude below those required ...19921622242
hyperreiterated dna regions are conserved among bradyrhizobium japonicum serocluster 123 strains.we have identified and cloned two dna regions which are highly reiterated in bradyrhizobium japonicum serocluster 123 strains. while one of the reiterated dna regions, pfr2503, is closely linked to the b. japonicum common and genotype-specific nodulation genes in strain usda 424, the other, pmap9, is located next to a tn5 insertion site in a host-range extension mutant of b. japonicum usda 438. the dna cloned in pfr2503 and pmap9 are reiterated 18 to 21 times, respectively, in the genomes of b. ...19921622264
characterization of a bradyrhizobium japonicum ferrochelatase mutant and isolation of the hemh gene.a tn5-induced mutant of bradyrhizobium japonicum, strain lorbf1, was isolated on the basis of the formation of fluorescent colonies, and stable derivatives were constructed in backgrounds of strains lo and i110. the stable mutant strains loek4 and i110ek4 were strictly dependent upon the addition of exogenous hemin for growth in liquid culture and formed fluorescent colonies. the fluorescent compound was identified as protoporphyrin ix, the immediate precursor of protoheme. cell extracts of stra ...19921624416
formation of novel polysaccharides by bradyrhizobium japonicum bacteroids in soybean nodules.certain strains of bradyrhizobium japonicum form a previously unknown polysaccharide in the root nodules of soybean plants (glycine max (l.) merr.). the polysaccharide accumulates inside of the symbiosome membrane-the plant-derived membrane enclosing the bacteroids. in older nodules (60 days after planting), the polysaccharide occupies most of the symbiosome volume and symbiosomes become enlarged so that there is little host cytoplasm in infected cells. the two different groups of b. japonicum w ...199216348649
the soybean rj4 allele restricts nodulation by bradyrhizobium japonicum serogroup 123 strains.of nine bradyrhizobium japonicum serogroup 123 strains examined, 44% were found to be restricted for nodulation by cultivar hill. nodulation studies with soybean isoline barc-2 confirmed that the soybean rj4 allele restricts nodulation by the same serogroup 123 isolates. immunological analyses indicated that b. japonicum strains in serogroups 123 and 31 share at least one surface somatic antigen.199216348655
lysogeny in bradyrhizobium japonicum and its effect on soybean nodulation.rhizobiophage v, isolated from soil in the vicinity of soybean roots, was strongly lytic on bradyrhizobium japonicum 123b (usda 123) but only mildly lytic on strain l4-4, a chemically induced small-colony mutant of 123. numerous bacteriophage-resistant variants were isolated from l4-4 infected with phage v; two were studied in detail and shown to be lysogenic. the two, l4-4 (v5) and l4-4 (v12), are the first reported examples of temperate-phage infection in b. japonicum. phage v and its derivati ...199216348790
characterization of delta-aminolevulinic acid formation in soybean root nodules.formation of the heme precursor delta-aminolevulinic acid (ala) was studied in soybean root nodules elicited by bradyrhizobium japonicum. glutamate-dependent ala formation activity by soybean (glycine max) in nodules was maximal at ph 6.5 to 7.0 and at 55 to 60 degrees c. a low level of the plant activity was detected in uninfected roots and was 50-fold greater in nodules from 17-day-old plants; this apparent stimulation correlated with increases in both plant and bacterial hemes in nodules comp ...199216668729
pyrroline-5-carboxylate reductase in soybean nodules : comparison of the enzymes in host cytosol, bradyrhizobium japonicum bacteroids, and cultures.characteristics of pyrroline-5-carboxylate reductase (p5cr) from bradyrhizobium japonicum bacteroids and cultured rhizobia were compared with those of the enzyme in soybean nodule host cytosol. reductase from host cytosol differed from that in bacteroids in: (a) the effect of ph on enzymic activity, (b) the capacity to catalyze both reduction of pyrroline-5-carboxylic acid and nad(+)-dependent proline oxidation, (c) apparent affinities for pyrroline-5-carboxylic acid, and (d) sensitivities to in ...199216668837
photosynthate metabolism in the source leaves of n(2)-fixing soybean plants.soybean plants (glycine max [l.] merr. cv williams), which were symbiotic with bradyrhizobium japonicum, and which grew well upon reduced nitrogen supplied solely through n(2) fixation processes, often exhibited excess accumulation of starch and sucrose and diminished soluble protein in their source leaves. nitrate and ammonia, when supplied to the nodulated roots of n(2)-fixing plants, mediated a reduction of foliar starch accumulation and a corresponding increase in soluble protein in the sour ...199216668977
labeling of carbon pools in bradyrhizobium japonicum and rhizobium leguminosarum bv viciae bacteroids following incubation of intact nodules with co(2).the aim of the work reported here was to ascertain that the patterns of labeling seen in isolated bacteroids also occurred in bacteroids in intact nodules and to observe early metabolic events following exposure of intact nodules to (14)co(2). intact nodules of soybean (glycine max l. merr. cv ripley) inoculated with bradyrhizobium japonicum usda 110 and pea (pisum sativum l. cv progress 9) inoculated with rhizobium leguminosarum bv viciae isolate 128c53 were detached and immediately fed (14)co( ...199216653034
p relaxation responses associated with n(2)/o(2) diffusion in soybean nodule cortical cells and excised cortical tissue.n(2)-fixing bradyrhizobium japonicum nodules and cortical tissue derived from these nodules were examined in vivo by (31)p nuclear magnetic resonance (nmr) spectroscopy. perfusion of the viable nodules and excised cortical tissue with o(2) followed by n(2) or ar caused a loss of orthophosphate (pi) resonance magnetization associated with the major portion of acidic pi (delta 0.9 ppm, ph 5.5) residing in the cortical cells. resumption of o(2) perfusion restored approximately 80% of the intensity ...199216653184
accumulation of the phytoalexin, glyceollin, in root nodules of soybean formed by effective and ineffective strains ofbradyrhizobium japonicum.nitrogen fixation in root nodules formed by strain 2143 ofbradyrhizobium japonicum andglycine max (l.) merr. cv williams 82 reaches a maximum at 21 to 28 days postinoculation and then begins to decline. the phytoalexin, glyceollin, accumulates in nodules coincident with the decline in nitrogen fixation. nodules formed by strain 3122, which are unable to fix nitrogen, accumulate even higher levels of glyceollin and do so beginning 21 days postinoculation even though these nodules contain no recov ...199224254143
chitinase and peroxidase in effective (fix(+)) and ineffective (fix (-)) soybean nodules.chitinase and peroxidase, two enzymes thought to be involved in the defense of plants against pathogens, were measured in soybean (glycine max l. merr.) roots and in nodules colonized by bradyrhizobium japonicum strains differing in their symbiotic potential. activities of both enzymes were higher in nodules than in roots. in "effective", nitrogen-fixing nodules, colonized by wild-type bacteria, chitinase and peroxidase activities had low levels in the central infected zone and were enhanced pri ...199224178068
real continuous biomass production ofbradyrhizobium japonicum in a veterinary vaccine production unit.in a real continuous culture,bradyrhizobium japonicum strain 1755 was maintained in the 'göttingen bioreactor unit' developed to produce veterinary bacterial vaccines for a period of 110 days without contamination or mutations. the average yield of viable bacteria over the whole period was more than 10(10)/ml.199224425338
hydrogenase in bradyrhizobium japonicum: genetics, regulation and effect on plant growth.a region of 15 kbp dna located on the chromosome of bradyrhizobium japonicum is essential for a hup(+) phenotype and contains the hydrogenase structural genes. during the last few years, other genes with various functions related to hydrogenase oxidation, such as ni(2+) incorporation into the hydrogenase enzyme, electron transport from hydrogenase to o2, and regulation of hydrogenase expression in free-living conditions, have been identified in this region. a region in front of the hydrogenase s ...199324420286
effects of ph and osmotic stress on cellular polyamine contents in the soybean rhizobia rhizobium fredii p220 and bradyrhizobium japonicum a1017.homospermidine is a polyamine present in its highest concentrations in root nodule bacteria. by using the soybean rhizobia rhizobium fredii p220 and bradyrhizobium japonicum a1017, the effects of the ph and osmolarity of the medium on rhizobial growth and cellular polyamine contents were investigated. elevation of medium ph repressed the growth of slowly growing b. japonicum a1017 and resulted in a slight increase in cellular putrescine, while homospermidine content was not significantly affecte ...199316348911
siderophore utilization by bradyrhizobium japonicum.bradyrhizobium japonicum usda 110 and 61a152 can utilize the hydroxamate-type siderophores ferrichrome and rhodotorulate, in addition to ferric citrate, to overcome iron starvation. these strains can also utilize the pyoverdin-type siderophore pseudobactin st3. the ability to utilize another organism's siderophores may confer a selective advantage in the rhizosphere.199316348945
plasmids pjp4 and r68.45 can be transferred between populations of bradyrhizobia in nonsterile soil.incp plasmid r68.45, which carries several antibiotic resistance genes, and incp plasmid pjp4, which contains genes for mercury resistance and 2,4-dichlorophenoxyacetic acid degradation, were evaluated for their ability to transfer to soil populations of rhizobia. transfer of r68.45 was detected in nonsterile soil by using bradyrhizobium japonicum usda 123 as the plasmid donor and several bradyrhizobium sp. strains as recipients. plasmid transfer frequencies ranged up to 9.1 x 10 in soil amended ...199316348953
presence of culturable bacteria in cocoons of the earthworm eisenia fetida.viable bacteria were found to coexist with developing embryos in egg capsules (cocoons) of the earthworm eisenia fetida. earthworms were reared under standardized conditions, and bacterial densities were measured in distinct batches of cocoons collected weekly for 10 weeks. cocoons weighing 12 mg contained a mean viable bacterial population of approximately 10 cfu/g of cocoons. no difference was found in viable counts obtained from cocoons incubated at 15 degrees c and cocoons incubated at 24 de ...199316348968
cloning of protocatechuate 3,4-dioxygenase genes from bradyrhizobium japonicum usda110.a heterologous gene probe encoding the alpha and beta subunits of the pseudomonas cepacia protocatechuate 3,4-dioxygenase (pcd) was used to detect its homolog in the genome of bradyrhizobium japonicum usda110. three cosmid clones carrying a 2.2-kb bamhi insert showed high levels of pcd activity. saci digestion of one of the genomic clones, pbjg17, produced a 2.5-kb insert dna that complemented a pcd mutant of p. cepacia.199316349024
genotypic diversity among strains of bradyrhizobium japonicum belonging to serogroup 110.thirty-three strains of bradyrhizobium japonicum within serogroup 110 were examined for genotypic diversity by using dna-dna hybridization analyses. the analysis of the dna from 15 hydrogen-uptake-negative strains with the bradyrhizobial uptake hydrogenase probe phu52 showed variation in degree of homology and restriction fragment length polymorphism of ecori-restricted dna. clustering analysis of the 33 strains on the basis of dna-dna hybridization analysis with four restriction enzymes and wit ...199316349053
cloning and mutagenesis of a cytochrome p-450 locus from bradyrhizobium japonicum that is expressed anaerobically and symbiotically.cytochromes p-450, which in many organisms participate in the metabolism of a variety of endobiotic and xenobiotic substances, are synthesized by symbiotic bacteroids of bradyrhizobium japonicum. polyclonal antibodies were raised against two cytochromes p-450 (cyp112 and cyp114) purified from bacteroids. a lambda gt11 expression clone of b. japonicum usda 110 dna that reacted with the anti-cyp112 antibody was obtained and was used to screen a library of usda 110 genomic dna in plafr1 for a clone ...199316349113
uptake hydrogenase (hup) in common bean (phaseolus vulgaris) symbioses.strains of rhizobium forming nitrogen-fixing symbioses with common bean were systematically examined for the presence of the uptake hydrogenase (hup) structural genes and expression of uptake hydrogenase (hup) activity. dna with homology to the hup structural genes of bradyrhizobium japonicum was present in 100 of 248 strains examined. ecori fragments with molecular sizes of approximately 20.0 and 2.2 kb hybridized with an internal saci fragment, which contains part of both bradyrhizobial hup st ...199316349115
bradyrhizobium japonicum delta-aminolevulinic acid dehydratase is essential for symbiosis with soybean and contains a novel metal-binding domain.the bradyrhizobium japonicum hema gene product delta-aminolevulinic acid (ala) synthase is not required for symbiosis of that bacterium with soybean. hence, the essentiality of the subsequent heme synthesis enzyme, ala dehydratase, was examined. the b. japonicum ala dehydratase gene, termed hemb, was isolated and identified on the basis of its ability to confer hemin prototrophy and enzyme activity on an escherichia coli hemb mutant, and it encoded a protein that was highly homologous to ala deh ...19938226669
nucleotide sequence analysis of four genes, hupc, hupd, hupf and hupg, downstream of the hydrogenase structural genes in bradyrhizobium japonicum.the nucleotide sequence of a 2.2 kb region downstream of the hydrogenase structural genes in bradyrhizobium japonicum was determined. four genes encoding predicted polypeptides of 27.8 (hupc), 21.4 (hupd), 10.6 (hupf) and 15.8 (hupg) kda were identified, of which the first three probably belong to the same operon as the hup structural genes, hups and hupl. hupc is homologous to the hydrophobic polypeptides with four potential transmembrane regions that are encoded by open reading frames followin ...19938230232
formation of several bacterial c-type cytochromes requires a novel membrane-anchored protein that faces the periplasm.we report here the discovery of a novel bacterial gene (cych) whose product is involved in the biogenesis of most of the cellular cytochromes c. the cych gene was detected in the course of characterizing a cytochrome oxidase-deficient bradyrhizobium japonicum tn5 mutant (strain cox3) in which the transposon insertion disrupted cych. all of the c-type cytochromes detectable in aerobically grown b. japonicum wild-type cells were absent in the cox3 mutant, with the exception of cytochrome c1. a sec ...19938231805
proposal for rejection of agrobacterium tumefaciens and revised descriptions for the genus agrobacterium and for agrobacterium radiobacter and agrobacterium rhizogenes.the 16s rrna sequences of seven representative agrobacterium strains, eight representative rhizobium strains, and the type strains of azorhizobium caulinodans and bradyrhizobium japonicum were determined. these strains included the type strains of agrobacterium tumefaciens, agrobacterium rhizogenes, agrobacterium radiobacter, agrobacterium vitis, agrobacterium rubi, rhizobium fredii, rhizobium galegae, rhizobium huakuii, rhizobium leguminosarum, rhizobium loti, rhizobium meliloti, and rhizobium ...19938240952
bradyrhizobium japonicum tlpa, a novel membrane-anchored thioredoxin-like protein involved in the biogenesis of cytochrome aa3 and development of symbiosis.we report the discovery of a bacterial gene, tlpa, that codes for a hitherto unknown type of thioredoxin-like protein. the gene was found in the course of studying a tn5 insertion mutant of the soybean root nodule symbiont bradyrhizobium japonicum. the tlpa protein shared up to 31% amino acid sequence identity with various eukaryotic and prokaryotic thioredoxins and protein disulfide isomerases, and possessed a characteristic active-site sequence, trp-cys-val-pro-cys. in contrast to all members ...19938253065
nolmno genes of bradyrhizobium japonicum are co-transcribed with nodyabcsuij, and nolo is involved in the synthesis of the lipo-oligosaccharide nodulation signals.a host-inducible lacz fusion was mapped down-stream of the nodyabcsuij operon in bradyrhizobium japonicum strain usda110. sequencing of this region identified three novel genes, nolmno. rna dot blot analysis showed that nolo transcription is nodd1-dependent and that a polar mutation in nods, located 5 kilobases upstream of nolo, blocks the transcription of nolo. coupled with the host-inducible nature of nolo expression, these results indicate that nolmno are part of a 9-kilobase operon, nodyabcs ...19938262943
a novel response-regulator is able to suppress the nodulation defect of a bradyrhizobium japonicum nodw mutant.the two-component regulatory system nod-vw of bradyrhizobium japonicum is essential for the nodulation of the legume host plants vigna radiata, v. unguiculata and macroptilium atropurpureum. the nodv protein shares homology with the sensor-kinases, whereas the nodw protein is a member of the response-regulator class. we report here the identification of a new b. japonicum dna region that is able to suppress the phenotypic defect of a nodw mutant, provided that this region is expressed from a for ...19938264528
identification and cloning of a cyclic beta-(1-->3), beta-(1-->6)-d-glucan synthesis locus from bradyrhizobium japonicum.a cosmid clone complementing a cyclic beta-(1-->2)-glucan biosynthesis (ndvb) mutant of rhizobium meliloti was isolated from a bradyrhizobium japonicum gene library. this clone specified synthesis of beta-(1-->3), beta-(1-->6)-linked glucans in r. meliloti. the complemented strain was osmotically tolerant and symbiotically competent on alfalfa. thus, beta-(1-->3), beta-(1-->6)-glucans can substitute functionally for beta-(1-->2)-glucans in r. meliloti.19938282182
[use of cheese whey for growing the bradyrhizobium japonicum e-109 strain].the growth of bradyrhizobium japonicum e-109 using cheese whey as carbon source was studied. the cheese whey was previously hydrolyzed by acid or enzymatic treatment with purified beta galactosidase or a crude extract from kluyveromyces fragilis. the results obtained demonstrated that the use of the modified enzymatic hydrolyzed whey as carbon source allowed the growth of b. japonicum e-109 reaching a concentration of approximately 10(10) viable cells/ml. these results are considered of industri ...19938153350
cyclic [beta]-1,6 -1,3 glucans are synthesized by bradyrhizobium japonicum bacteroids within soybean (glycine max) root nodules.we have previously reported that free-living cultures of bradyrhizobium species produce novel oligosaccharides that are cyclic, contain between 10 and 13 glucose residues, and are linked by [beta]-1,6 and [beta]-1,3 glycosidic bonds (k.j. miller, r.s. gore, r. johnson, a.j. benesi, v.n. reinhold [1990] j bacteriol 172: 136-142). in the present study, we show that these glucans are also synthesized by bacteroids of bradyrhizobium japonicum usda 110 within glycine max root nodules.199312231809
kinetics of nodule development in glycine soja.nodule development in the interaction of glycine soja sieb. & zucc. pi468.397 with bradyrhizobium japonicum usda110 was studied by hypochlorite clearing and methylene blue staining. even the earliest stages of nodule development could be observed. the entire length of the primary root was examined up to 15 d postinoculation. markedly curled root hairs and the first cell divisions in the hypodermal layer (stage i) were observed 2 d postinoculation, and by 3 d cell division activity had spread to ...199312232007
phylogenetic analysis of the family rhizobiaceae and related bacteria by sequencing of 16s rrna gene using pcr and dna sequencer.the 16s rrna gene sequences of 19 strains covering 97% of the molecules were determined for the members of the family rhizobiaceae and related bacteria by pcr and dna sequencer. the three biovars of agrobacterium were located separately, whereas agrobacterium rubi clustered with a. tumefaciens. phylogenetic locations for the species of the genera rhizobium, sinorhizobium, agrobacterium, phylobacterium, mycoplana (m. dimorpha), ochrobactrum, brucella and rochalimaea (a rickettsia) were intermingl ...19937682191
tn5-mob transposon mediated transfer of salt tolerance and symbiotic characteristics between rhizobia genera.rhizobium meliloti 042b is a fast-growing, salt-tolerant and high efficiency nitrogen-fixing symbiont with alfalfa. bradyrhizobium japonicum usda110 grows slowly, and cannot grow in yma medium containing 0.1m nacl, but nodulates and fixed nitrogen efficiently with soybean. eighty-six transconjugants, called sr, were obtained by inserting tn5-mob randomly into genomes of 042b using psup5011 and helper plasmid rp4. selecting 4 sr strains randomly and introducing dna fragment of sr into usda110 wit ...19938049344
use of repetitive sequences and the polymerase chain reaction technique to classify genetically related bradyrhizobium japonicum serocluster 123 strains.we have determined that repetitive (repetitive extragenic palindromic [rep] and enterobacterial repetitive intergenic consensus [eric]) sequences used in conjunction with the polymerase chain reaction technique (rep and eric pcr) provide an effective means of differentiating between and classifying genetically related bradyrhizobium japonicum serocluster 123 strains. analysis of rep and eric pcr-generated dendrograms indicated that this technique can effectively differentiate between closely rel ...19938101072
one member of a gro-esl-like chaperonin multigene family in bradyrhizobium japonicum is co-regulated with symbiotic nitrogen fixation genes.this report is concerned with the structural characterization and genetic regulation of new bacterial groes and groel chaperonin genes, and presents two novelties. the first is the discovery that the nitrogen fixing soybean root nodule bacterium, bradyrhizobium japonicum, unlike all other prokaryotes investigated so far, possesses a multigene family consisting of five very similar, though not identical, groesl-like genes. the second novelty relates to the finding that these five homologues are e ...19938101485
biological activity of rhizobium sp. ngr234 nod-factors on macroptilium atropurpureum.the broad host range of rhizobium sp. ngr234 is based mainly on its ability to secrete a family of lipooligosaccharide nod factors. to monitor nod-factor purification, we used the small seeded legume macroptilium atropurpureum, which responds evenly and consistently to nod factors. at concentrations between approximately equal to 10(-11) m and 10(-9) m, this response takes the form of deformation of the root hairs. higher concentrations (approximately equal to 10(-9) to 10(-7) m), provoked profo ...19938118058
the nodl and nodj proteins from rhizobium and bradyrhizobium strains are similar to capsular polysaccharide secretion proteins from gram-negative bacteria.the nodl and nodj nodulation proteins have been described in different rhizobium and bradyrhizobium species. the nodlj genes belong to the nod regulon. other genes from this regulon are involved in the biosynthesis and modification of lipo-oligosaccharide molecule(s) which are morphogenic signals when acting on legume roots. it has been proposed that the nodl and nodj proteins belong to a bacterial inner membrane transport system of small molecules. nucleotide sequencing of mudll pr13 insertions ...19938316086
rapid and efficient selection of recombinant site-directed mutants of bradyrhizobium japonicum by colony hybridization.due to the high incidence of spontaneous antibiotic resistance and slow growth of bradyrhizobium japonicum strains, screening for site-directed mutants is cumbersome and time-consuming. a rapid method for selection of recombinant site-directed mutants of b. japonicum was developed. a kanamycin (km) and a spectinomycin (sp) cassette were each used to replace dna fragments in the chromosome by homologous recombination. the primary new features of this method involve a simple plate selection for th ...19938319882
use of a promoter-probe vector system in the cloning of a new nifa-dependent promoter (ndp) from bradyrhizobium japonicum.many of the symbiotic nitrogen-fixation genes in the soybean root nodule bacterium, bradyrhizobium japonicum, are transcribed from -24/-12 promoters that are recognized by the sigma 54-rna polymerase and activated by the transcriptional regulator protein, nifa. several lines of evidence suggest that the b. japonicum genome has more than those seven nifa-regulated promoters which were characterized previously. here, we present a strategy aimed at the cloning of new nifa-activated promoters. it ma ...19938335258
the structures and biological activities of the lipo-oligosaccharide nodulation signals produced by type i and ii strains of bradyrhizobium japonicum.bradyrhizobium japonicum produces lipo-oligosaccharide signal molecules that induce deformation of root hairs and meristematic activity on soybeans. b. japonicum usda135 (a type i strain) produces modified chitin pentasaccharide molecules with either a terminal n-c16:0- or n-c18:1-glucosamine with and without an o-acetyl group at c-6 and with 2-o-methylfucose linked to c-6 of the reducing n-acetylglucosamine. an additional molecule has n-c16:1-glucosamine and no o-acetyl group. all of these mole ...19938349712
expression of hydrogenase in hupc strains of bradyrhizobium japonicum.plasmid-borne hup-lacz transcriptional fusion constructs were introduced into three separate mutant strains of bradyrhizobium japonicum which express hydrogenase constitutively (hupc strains sr470, sr473 and jh101) in both autotrophic and heterotrophic environments. the lacz structural gene linked directly to the regulatory region upstream of the hydrogenase structural gene encompassing -149 bases expressed beta-gal at a constant, high level, in response to various concentrations of ni (0 microm ...19938352650
hydrogen-ubiquinone oxidoreductase activity by the bradyrhizobium japonicum membrane-bound hydrogenase.the bradyrhizobium japonicum heterodimeric nickel-iron hydrogenase efficiently catalyzed h2-ubiquinone-1 oxidoreductase activity at rates up to 47% of the maximal rates obtained using the artificial electron acceptor methylene blue. gel filtration chromatography and sds-polyacrylamide gel electrophoresis experiments demonstrated that the purified enzyme was a heterodimer containing only the 65 kda and 33 kda subunits. reduced minus oxidized absorption difference spectra demonstrated the absence ...19938354459
characterization of the ntrbc genes of azospirillum brasilense sp7: their involvement in the regulation of nitrogenase synthesis and activity.a 7.1 kb ecori fragment from azospirillum brasilense, that hybridized with a probe carrying the ntrbc genes from bradyrhizobium japonicum, was cloned. the nucleotide sequence of a 3.8 kb subfragment was established. this led to the identification of two open reading frames, encoding polypeptides of 401 and 481 amino acids, that were similar to ntrb and ntrc, respectively. a broad host range plasmid containing the putative azospirillum ntrc gene was shown to restore nitrogen fixation under free-l ...19938355653
analysis of the bradyrhizobium japonicum hemh gene and its expression in escherichia coli.complementation analysis showed that the bradyrhizobium japonicum hemh gene was both necessary and sufficient to rescue mutant strains i110ek4 and i110bk2 in trans with respect to hemin auxotrophy, protoporphyrin accumulation, and the deficiency in ferrochelatase activity. the b. japonicum hemh gene was expressed in an escherichia coli t7 expression system and yielded a 39-kda protein, which was consistent with the predicted size of the deduced product. the overexpressed protein was purified and ...19938368826
oxygen-dependent transcriptional regulation of cytochrome aa3 in bradyrhizobium japonicum.cytochrome aa3 is one of two terminal oxidases expressed in free-living bradyrhizobium japonicum but not symbiotically in bacteroids. difference spectra (dithionite reduced minus ferricyanide oxidized) for membranes from cells incubated with progressively lower o2 concentrations showed a concomitant decrease in the a603, the absorption peak characteristic of cytochrome aa3. the level of n,n,n',n'-tetramethyl-p-phenylenediamine oxidase activity, a measure of cytochrome aa3 activity, was also foun ...19938380149
characterization of rfrs9, a second member of the rhizobium fredii repetitive sequence family from the nitrogen-fixing symbiont r. fredii usda257.the genome of the nitrogen-fixing symbiont, rhizobium fredii usda257, contains nine copies of repetitive sequences known as the r. fredii repetitive sequence (rfrs) family. we previously sequenced rfrs3, which is linked to symbiosis plasmid-borne nodulation genes of this organism and has substantial homology to the t-dna of agrobacterium rhizogenes and lesser homology to reiterated sequences of bradyrhizobium japonicum. here we characterize a second family member, rfrs9. the ecori fragment conta ...19938382462
genes for a microaerobically induced oxidase complex in bradyrhizobium japonicum are essential for a nitrogen-fixing endosymbiosis.we report the discovery of a bradyrhizobium japonicum gene cluster (fixnoqp) in which mutations resulted in defective soybean root-nodule bacteroid development and symbiotic nitrogen fixation. the predicted, dna-derived protein sequences suggested that fixn is a heme b and copper-binding oxidase subunit, fixo a monoheme cytochrome c, fixq a polypeptide of 54 amino acids, and fixp a diheme cytochrome c and that they are all membrane-bound. the isolation and analysis of membrane proteins from b. j ...19938386371
the bradyrhizobium japonicum serocluster 123 hyperreiterated dna region, hrs1, has dna and amino acid sequence homology to is1380, an insertion sequence from acetobacter pasteurianus.we have sequenced and analyzed the hyperreiterated dna region, hrs1, from bradyrhizobium japonicum usda 424. the 2.1-kb hrs1 fragment is closely linked to the b. japonicum common and genotype-specific nodulation genes in serogroup 123 and 127 strains. southern hybridization analyses indicated that one copy of hrs1 is also located next to the fixrnifa locus in b. japonicum usda 424. nucleotide sequence analysis revealed the presence of a 4-bp target site duplication in hrs1 which is identical to ...19938390818
purification and characterization of an o2-utilizing cytochrome-c oxidase complex from bradyrhizobium japonicum bacteroid membranes.a cytochrome-c (cyt c) oxidase supercomplex consisting of 7-8 subunits and possessing a mass of 358-425 kda was purified from bradyrhizobium japonicum bacteroid membranes. at least two subunits possess c-type heme as a prosthetic group. one of the c-heme-containing components was detected in bacteroid membranes, but not in free-living cells. the complex also contains b-heme, and both b-type and c-type heme proteins were spectrophotometrically shown to form complexes with carbon monoxide. a co di ...19938399377
characterization of the soybean early nodulin cdna clone gmenod55.two cdna clones of the soybean early nodulin gmenod55 were characterized. these clones may represent two members of the soybean early nodulin gene family gmenod55. gmenod55 has an n-terminal signal peptide and it contains an internal domain consisting of proline and serine residues. analyses of nodules lacking infection threads and intracellular bacteria suggest that the gmenod55 gene is first expressed after release of bradyrhizobium japonicum in plant cells. this conclusion is supported by in ...19938400132
identification of nodsuij genes in nod locus 1 of azorhizobium caulinodans: evidence that nods encodes a methyltransferase involved in nod factor modification.the azorhizobium caulinodans strain ors571 nodulation genes nodsuij were located downstream from nodabc. complementation data and transcriptional analysis suggest that nodabcsuij form a single operon. mutants with tn5 insertions in the genes nods, nodu, and nodj were delayed in nodulation of sesbania rostrata roots and stems. the nods amino acid sequences of ors571, bradyrhizobium japonicum, and rhizobium sp. strain ngr234, contain a consensus with similarity to s-adenosylmethionine (sam)-utiliz ...19938412659
a genetic region downstream of the hydrogenase structural genes of bradyrhizobium japonicum that is required for hydrogenase processing.deletion of a 2.9-kb chromosomal ecori fragment of dna located 2.2 kb downstream from the end of the hydrogenase structural genes resulted in the complete loss of hydrogenase activity. the normal 65- and 35-kda hydrogenase subunits were absent in the deletion mutants. instead, two peptides of 66.5 and 41 kda were identified in the mutants by use of anti-hydrogenase subunit-specific antibody. a hydrogenase structural gene mutant did not synthesize either the normal hydrogenase subunits or the lar ...19938416905
correlated physical and genetic map of the bradyrhizobium japonicum 110 genome.we describe a compilation of 79 known genes of bradyrhizobium japonicum 110, 63 of which were placed on a correlated physical and genetic map of the chromosome. genomic dna was restricted with enzymes paci, pmei, and swai, which yielded two, five, and nine fragments, respectively. linkage of some of the fragments was established by performing southern blot hybridization experiments. for probes we used isolated, labelled fragments that were produced either by pmei or by swai. genes were mapped on ...19938423135
expression and regulation of bradyrhizobium japonicum and xanthobacter flavus co2 fixation genes in a photosynthetic bacterial host.calvin cycle carbon dioxide fixation genes encoded on dna fragments from two nonphotosynthetic, chemolithoautotrophic bacteria, bradyrhizobium japonicum and xanthobacter flavus, were found to complement and support photosynthetic growth of a ribulose 1,5-bisphosphate carboxylase-oxygenase (rubisco) deletion mutant of the purple nonsulfur bacterium rhodobacter sphaeroides. the regulation of rubisco expression was analyzed in the complemented r. sphaeroides rubisco deletion mutant. distinct differ ...19938423157
biosynthesis of cyclic beta-(1-3),beta-(1-6) glucan in bradyrhizobium spp.inner membranes of bradyrhizobium japonicum strain usda 110 produced in vitro soluble and insoluble beta-(1-3),beta-(1-6) glucans. the reaction proceeded through a 90 kda inner membrane intermediate protein; used udp-glucose as sugar donor and required mg2+. gel chromatography of soluble glucans resolved a cyclic beta-(1-3) glucan with a degree of polymerization of eleven from a family of beta-(1-3),beta-(1-6) glucans with variable degree of polymerization higher than eleven. bradyrhizobium stra ...19938427547
bradyrhizobium japonicum rhizobitoxine genes and putative enzyme functions: expression requires a translational frameshift.some strains of bradyrhizobium japonicum produce rhizobitoxine, a phytotoxin that causes foliar chlorosis on susceptible host plants. we have previously obtained tn5-induced rhizobitoxine null mutants of b. japonicum. dna sequence analysis of the region surrounding two tn5 insertions identifies two overlapping open reading frames. the first open reading frame (rtxa) predicts a 54-kda protein for which the n-terminal 280 residues have sequence similarity to serine: pyruvate aminotransferase. the ...19938464870
carbohydrate binding activities of bradyrhizobium japonicum: unipolar localization of the lectin bj38 on the bacterial cell surface.a polyclonal antiserum generated against the bradyrhizobium japonicum lectin bj38 was characterized to be specifically directed against the protein. treatment of b. japonicum cells with this antiserum and subsequent visualization with transmission electron microscopy and both conventional and confocal fluorescence microscopy revealed bj38 at only one pole of the bacterium. bj38 appeared to be organized in a tuft-like mass, separated from the bacterial outer membrane. bj38 localization was coinci ...19938464919
identification of a potential transcriptional regulator of hydrogenase activity in free-living bradyrhizobium japonicum strains.in bradyrhizobium japonicum, tn5 insertions in a particular chromosomal dna fragment result in a hup- phenotype in free-living conditions without affecting hydrogenase (hup) activity in the symbiotic state. by determination of the nucleotide sequence of this region, we were able to identify the nature of the inactivated genes. the fragment is located 9 kb downstream of the hydrogenase structural genes and contains one incomplete and three complete open reading frames. they are designated hypd', ...19938510650
rhodobacter capsulatus contains a novel cb-type cytochrome c oxidase without a cua center.the facultative phototrophic bacterium rhodobacter capsulatus is capable of growth in a wide range of environmental conditions using a highly branched electron-transfer chain. during respiratory growth of this organism reducing equivalents are conveyed to oxygen via two terminal oxidases, previously called "cyt b410" (cytochrome c oxidase) and "cyt b260" (quinol oxidase). the cytochrome c oxidase was purified to homogeneity from a semiaerobically grown r. capsulatus strain. the purified enzyme c ...19948130227
novel malonamidases in bradyrhizobium japonicum. purification, characterization, and immunological comparison.three novel malonamidases (e1a, e1b, and e2) occurring constitutively in bradyrhizobium japonicum were purified to electrophoretic homogeneity. they were found to catalyze one or more of the following three types of reactions: malonyl transfer to hydroxylamine (reaction 1), hydroxaminolysis of malonamate (reaction 2), and hydrolysis of malonamate (reaction 3). the molecular sizes of e1a, e1b, and e2 were 126, 107, and 103 kda, respectively, and they were each composed of two identical subunits. ...19948132523
cytochrome oxidase evolved by tinkering with denitrification enzymes.the cytochrome bc complex which is encoded by the fixnopq operon in bradyrhizobium japonicum, is the most distant member of the haem-copper cytochrome oxidase family. we have found that its major subunit, fixn, is homologous to the norb subunit of nitric oxide reductase in a purple bacterium. a second evolutionary link between cytochrome oxidases and denitrification enzymes is the presence of a similar binuclear copper site in cytochrome aa3 (the mitochondrial oxidase) and nitrous oxide reductas ...19948137905
effect of iron availability on expression of the bradyrhizobium japonicum hema gene.bradyrhizobium japonicum produces delta-aminolevulinic acid, the universal precursor of tetrapyrroles, in a reaction catalyzed by the product of the hema gene. expression of the b. japonicum hema gene is affected by iron availability. activity of a hema-lacz fusion is increased approximately threefold by iron, and rna analysis indicates that iron regulation is at the level of mrna accumulation. to our knowledge, this is the first example of an iron-regulated heme biosynthetic gene in prokaryotes ...19948113199
cytochrome aa3 gene regulation in members of the family rhizobiaceae: comparison of copper and oxygen effects in bradyrhizobium japonicum and rhizobium tropici.dithionite-reduced minus ferricyanide-oxidized difference spectra on membranes from rhizobium tropici (formerly rhizobium leguminosarum bv. phaseoli) incubated at progressively lower o2 concentrations showed only a slight concomitant decrease in a603, the alpha-peak of cytochrome aa3. in contrast to previous results on bradyrhizobium japonicum, r. tropici showed no significant o2-mediated reduction in the level of either coxa transcription or cytochrome aa3 activity (as measured by ascorbate-n,n ...19948117073
carbohydrate binding activities of bradyrhizobium japonicum. iii. lectin expression, bacterial binding, and nodulation efficiency.in previous studies, evidence that the bradyrhizobium japonicum lectin, designated bj38, mediated the observed carbohydrate-specific binding activities of the bacteria, including the saccharide-specific adhesion to soybean root cells was presented. in the present study, it is found that both b. japonicum, as well as the purified bj38, bind predominantly to young emergent root hairs of soybean roots and, to a much lesser extent, to the root cap, mature root hairs, epicotyl or hypocotyl regions. t ...19948054992
expression, purification and functional properties of a soluble form of bradyrhizobium japonicum tlpa, a thioredoxin-like protein.the tlpa protein of bradyrhizobium japonicum was previously identified genetically as a membrane-anchored, periplasmic thioredoxin-like protein. here we describe the heterologous expression in escherichia coli, subsequent purification and biochemical characterization of tlpa. a soluble form of tlpa, which lacks its n-terminal membrane anchor, was overexpressed in e. coli and purified by a two-step procedure. pure tlpa was shown to be a monomer in solution and was active in reducing the disulfide ...19948055901
bacterial genes and proteins involved in the biogenesis of c-type cytochromes and terminal oxidases.a total of nine genes potentially concerned with the biosynthesis of c-type cytochromes have been identified recently in the bacteria bradyrhizobium japonicum and rhodobacter capsulatus, and homologous counterparts appear to be present also in escherichia coli. most of the respective gene products are membrane-bound, while others are located in the periplasmic space. as inferred from sequence analyses, several of these proteins may play roles in membrane transport or redox processes, both functi ...19948075119
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