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measurement of nitrogen fixation by soybean in the field using the ureide and natural n abundance methods.nitrogen fixation by field-grown soybean (glycine max [l.] merrill) was assessed by the natural (15)n abundance and ureide methods. the field sites (five) and genotypes (six, plus two levels of inoculation on bragg) were chosen to provide a range of proportions of plant n derived from nitrogen fixation (p). genotypes k466, k468, nts1007, and nts1116 and davis were included on the basis of their reported tolerance of the suppressive effects of nitrate on nodulation and nitrogen fixation. bragg wa ...199016667527
effect of po(2) on growth and nodule functioning of symbiotic cowpea (vigna unguiculata l. walp.).nodulated cowpea (vigna unguiculata l. walp. cv vita 3:bradyrhizobium cb 756) plants were cultured with their whole root system or crown root nodulation zone maintained for periods from 5 to 69 days after planting in atmospheres containing a range of po(2) (1-80%, v/v) while the rest of the plant grew in normal air. growth (dry matter yield) and n(2) fixation were largely unaffected by po(2) from 10 to 40%. decrease in fixation at po(2) below 5% was due to lower nodulation and nodule mass and, a ...199016667605
effect of po(2) during growth on the gaseous diffusional properties of nodules of cowpea (vigna unguiculata l. walp.).adaptations of nodules of cowpea (vigna unguiculata l. walp. cv vita 3: bradyrhizobium cb 756) to growth in po(2) ranging from 1 to 80% o(2) (volume/volume) involved both readily reversible mechanisms of adjustment and more stable alterations which together resulted in nodules with widely ranging resistance to diffusion of gases. those grown in subambient po(2) (1-5% o(2) were altered such that rapid diffusional adjustment was unable to prevent irreversible loss of nitrogenase on their transfer ...199016667606
photosynthesis and photosynthate partitioning in n(2)-fixing soybeans.leaf area, chlorophyll content, net co(2) photoassimilation, and the partitioning of fixed carbon between leaf sucrose and starch and soluble protein were examined in glycine max (l) merr. cv williams grown under three different nitrogen regimes. one group (nod+/+) was inoculated with bradyrhizobium and watered daily with a nutrient solution containing 6 millimolar nh(4)no(3). a second set (nod+/-) was inoculated and had n(2) fixation as its sole source of nitrogen. a third group (nod(-)) was no ...199016667695
ammonia (c-methylamine) transport across the bacteroid and peribacteroid membranes of soybean root nodules.[(14)c]methylamine (ma; an analog of ammonia) was used to investigate ammonia transport across the bacteroid and peribacteroid membranes (pbm) from soybean (glycine max) root nodules. free-living bradyrhizobium japonicum usda110 grown under nitrogen-limited conditions showed rapid ma uptake with saturation kinetics at neutral ph, indicative of a carrier. exchange of accumulated ma for added ammonia occurred, showing that the carrier recognized both nh(4) (+) and ch(3)nh(3) (+). ma uptake by isol ...199016667721
glycine-glomus-bradyrhizobium symbiosis : x. relationships between leaf gas exchange and plant and soil water status in nodulated, mycorrhizal soybean under drought stress.soybean (glycine max [l.] merr.) plants were colonized by the vesicular-arbuscular mycorrhizal (vam) fungus glomus mosseae (nicol. and gerd.) gerd. and trappe (vam plants) or fertilized with kh(2)po(4) (nonvam plants) and grown for 50 days under controlled conditions. plants were harvested over a 4-day period during which the soil was permitted to dry slowly. the harvest was terminated when leaf gas exchange was no longer measurable due to drought stress. significantly different effects in shoot ...199016667771
early autoregulation of symbiotic root nodulation in soybeans.autoregulation of symbiotic root nodulation in soybean seedlings (glycine max l. merrill cv pride 216) was studied following double inoculation of primary roots with bradyrhizobium japonicum 110. when the second inoculation was given 10 or 17 hours after the first, the nodulation in the first-inoculated region of the root was suppressed. the effect was eliminated if b. japonicum 110 containing tn5 insertions in the ;common' nod abc genes was used for the second inoculation, indicating the requir ...199016667864
symbiotic effectiveness of indigenous soybean bradyrhizobia as related to serological, morphological, rhizobitoxine, and hydrogenase phenotypes.a collection of 360 isolates of bradyrhizobium japonicum was developed from soybean (glycine max [l.] merrill) nodules taken from 18 locations in delaware. the isolates were characterized serologically with an enzyme-linked immunosorbent assay, morphologically by colony type on yeast extract-mannitol agar, and for production of rhizobitoxine symptoms with soybean plants. these analyses revealed 12 and 3 groups based on serology and morphology, respectively. the more common identifiable isolates ...199016348095
growth, respiration, and polypeptide patterns of bradyrhizobium sp. (arachis) strain 3g4b20 from succinate- or oxygen-limited continuous cultures.succinate- or oxygen-limited continuous cultures were used to study the influences of different concentrations of dissolved oxygen and ammonia on the growth, respiration, and polypeptide patterns of bradyrhizobium sp. (arachis) strain 3g4b20. during succinate-limited growth, molar growth yields on succinate (y(succ)) ranged from 38.9 to 44.4 g (dry weight) of cells mol of succinate and were not greatly influenced by changes in dilution rates or changes in the oxygen concentrations that we tested ...199016348154
strain-specific inhibition of nod gene induction in bradyrhizobium japonicum by flavonoid compounds.a broad-host-range plasmid, pea2-21, containing a bradyrhizobium japonicum nodabc'-'lacz translational fusion was used to identify strain-specific inhibitors of the genes required for soybean nodulation, the common nod genes. the responses of type strains of b. japonicum serogroups usda 110, usda 123, usda 127, usda 129, usda 122, and usda 138 to nod gene inhibitors were compared. few compounds inhibited nod gene expression in b. japonicum usda 110. in contrast, nod gene expression in strains be ...199016348186
fractionation of the beta-linked glucans of bradyrhizobium japonicum and their response to osmotic potential.bradyrhizobium japonicum usda 110 synthesized both extracellular and periplasmic polysaccharides when grown on mannitol minimal medium. the extracellular polysaccharides were separated into a high-molecular-weight acidic capsular extracellular polysaccharide fraction (90% of total hexose) and three lower-molecular-weight glucan fractions by liquid chromatography. periplasmic glucans, extracted from washed cells with 1% trichloroacetic acid, gave a similar pattern on liquid chromatography. linkag ...199016348201
dna hybridization probe for use in determining restricted nodulation among bradyrhizobium japonicum serocluster 123 field isolates.several soybean plant introduction (pi) genotypes have recently been described which restrict nodulation of bradyrhizobium japonicum serocluster 123 in an apparently serogroup-specific manner. while pi 371607 restricts nodulation of strains in serogroup 123 and some in serogroup 127, those in serogroup 129 are not restricted. when dna regions within and around the b. japonicum i-110 common nodulation genes were used as probes to genomic dna from the serogroup strains usda 123, usda 127, and usda ...199016348217
mutant strain of bradyrhizobium japonicum with increased symbiotic n(2) fixation rates and altered mo metabolism properties.mutant strains of bradyrhizobium japonicum that required higher levels of molybdate than the wild-type strain for growth on no(3)-containing medium were obtained after transposon tn5 mutagenesis of the wild-type strain. the mutant strains expressed more than fivefold-greater nitrate reductase activities in the range of 0.1 to 1.0 mm added molybdate compared with activities expressed upon incubation in non-mo-supplemented medium, whereas the nitrate reductase activity of the wild-type strain (jh) ...199016348247
enhanced nodulation and nitrogen fixation by a revertant of a nodulation-defective bradyrhizobium japonicum tryptophan auxotroph.in greenhouse studies, the symbiotic properties of a prototrophic revertant (ta11 nod) of a nodulation defective tryptophan auxotroph of bradyrhizobium japonicum were compared with those of the normally nodulating wild-type strain, b. japonicum i-110 ars. strain i-110 ars was the parent of auxotrophic mutant ta11. plants inoculated with ta11 nod contained significantly more nitrogen per plant than did plants inoculated with wild-type bacteria (275.9 +/- 35 versus 184 +/- 18 mg). also, plants tha ...199016348254
hemoproteins of bradyrhizobium japonicum cultured cells and bacteroids.the hemoprotein content of 17 strains of bradyrhizobium japonicum bacteroids from field-grown plants and the corresponding strains of cultured cells was determined spectrally. the major terminal oxidases, cytochromes (cyt) aa(3) and o, were present in all strains of cultured cells. cyt aa(3) was present in significant amounts in bacteroids only in strains of dna homology group ii. cyt o appeared to be present in bacteroids of all strains, and the average level was the same as in cultured cells. ...199016348282
limiting an insect infestation of nitrogen-fixing root nodules of the pigeon pea (cajanus cajan) by engineering the expression of an entomocidal gene in its root nodules.a region of dna which determined the production of the insecticidal toxin of bacillus thuringiensis subsp. israelensis was cloned into a derivative of a broad-host-range group incq plasmid vector of gram-negative bacteria. the plasmid which we constructed was transferred by conjugative mobilization into a bradyrhizobium species that nodulates pigeon peas. in this species the construction was maintained stably in the absence of selection and expressed the gene that was installed. experiments in a ...199016348294
competitive ability and efficiency in nodule formation of strains of bradyrhizobium japonicum.in the american midwest, superior n(2)-fixing inoculant strains of bradyrhizobium japonicum consistently fail to produce the majority of nodules on the roots of field-grown soybean. poor nodulation by inoculant strains is partly due to their inability to stay abreast of the expanding soybean root system in numbers sufficient for them to be competitive with indigenous bradyrhizobia. however, certain strains are noncompetitive even when numerical dominance is not a factor. in this study, we tested ...199016348311
single-strain versus multistrain inoculation: effect of soil mineral n availability on rhizobial strain effectiveness and competition for nodulation on chick-pea, soybean, and dry bean.the nitrogen-fixing effectiveness of multistrain inoculants was found to be determined by both the effectiveness of the component strains and the percentage of the nodules occupied by them. multistrain formulations were always either as good as the most effective single-strain inoculant or intermediate between the most and the least effective. the percentage of nodules occupied and the amount of nitrogen fixed by the component strains of a multistrain inoculant showed highly significant linear c ...199016348337
evidence for a third uptake hydrogenase phenotype among the soybean bradyrhizobia.the existence of a hydrogen uptake host-regulated (hup-hr) phenotype was established among the soybean bradyrhizobia. the hup-hr phenotype is characterized by the expression of uptake hydrogenase activity in symbiosis with cowpea but not soybean. uptake hydrogenase induction is not possible under free-living cultural conditions by using techniques developed for uptake hydrogenase-positive (hup) bradyrhizobium japonicum. hydrogen oxidation by hup-hr phenotype usda 61 in cowpea symbioses was signi ...199016348383
molecular biology studies of the uptake hydrogenase of rhodobacter capsulatus and rhodocyclus gelatinosus.in the photosynthetic bacteria, as in other n2-fixing bacteria, two main enzymes are involved in h2 metabolism: nitrogenase, which catalyses the photoproduction of h2, and a membrane-bound (nife) hydrogenase, which functions as an h2-uptake enzyme. the structural genes for rhodobacter capsulatus and rhodocyclus gelatinosus uptake hydrogenases were isolated and sequenced. they present the same organization, with the gene encoding the small subunit (hups) (molecular masses 34.2 and 34.6 kda, respe ...19902094292
transcriptional regulation of hydrogenase synthesis by nickel in bradyrhizobium japonicum.nickel is a component of the h2-oxidizing hydrogenase of many bacteria. we report that nickel is required not only for the activity of the bradyrhizobium japonicum h2 uptake (hup) enzyme but also for the initiation of its transcription. a much greater level of hydrogenase-specific mrna was detected in cells that were derepressed for hydrogenase in the presence of 5 microm nickel than in the absence of nickel. control experiments involving probing of mrna with a b. japonicum gene encoding a non-n ...19902121729
soluble hydrogenase of anabaena cylindrica. cloning and sequencing of a potential gene encoding the tritium exchange subunit.a gene potentially encoding a subunit of the soluble hydrogenase of anabaena cylindrica was isolated from a genomic library by screening with a set of redundant oligonucleotides, the sequence of which was deduced from the amino acid sequence of the purified hydrogenase subunit that catalyses tritium exchange. the nucleotide sequence of the potential gene was determined from two overlapping dna fragments spanning 7237 bp of the a. cylindrica genome. the region sequenced contained an open reading ...19902129525
identification of nods and nodu, two inducible genes inserted between the bradyrhizobium japonicum nodyabc and nodij genes.the so-called common nodulation (nod) gene cluster of bradyrhizobium japonicum is characterized by a unique composition of genes that are arranged in the following order: nody, noda, nodb, nodc, nods, nodu, nodi, nodj. as reported here, the identification of the two new genes nods and nodu resulted from the dna sequencing of a 4.5-kilobase nodc-downstream region covering nods, nodu, nodi, and nodj. the predicted nods, nodu, nodi, and nodj proteins had the following respective amino acid (aa) len ...19902134855
nodsu, two new nod genes of the broad host range rhizobium strain ngr234 encode host-specific nodulation of the tropical tree leucaena leucocephala.rhizobium species strain ngr234 nodulates at least 35 diverse genera of legumes as well as the nonlegume parasponia andersonii. most nodulation genes are located on the 500-kilobase pair symbiotic plasmid, pngr234a. previously, three plasmid-borne host range determinants (hsni, hsnii, and hsniii) were identified by their ability to extend the nodulation capacity of heterologous rhizobia to include vigna unguiculata. in this study, we show that hsnii contains two new nod-box linked hsn genes, nod ...19902134856
citrate as a siderophore in bradyrhizobium japonicum.under iron-limiting conditions, many bacteria secrete ferric iron-specific ligands, generically termed siderophores, to aid in the sequestering and transport of iron. one strain of the nitrogen-fixing soybean symbiont bradyrhizobium japonicum, 61a152, was shown to produce a siderophore when 20 b. japonicum strains were screened with all six chemical assays commonly used to detect such production. production by strain 61a152 was detected via the chrome azurol s assay, a general test for sideropho ...19902140566
nucleotide sequence of the coxa gene encoding subunit i of cytochrome aa3 of bradyrhizobium japonicum. 19902172930
efficient dna transformation of bradyrhizobium japonicum by electroporation.intact cells of bradyrhizobium japonicum usda 110 were transformed with a 30-kilobase plasmid to efficiencies of 10(6) to 10(7) transformants per microgram by high-voltage electroporation. the technique was reliable and simple, with single colonies arising from transformed cells within 5 days of antibiotic selection. plasmid dna from b. japonicum transformed the bradyrhizobium (arachis) sp. with high efficiency, while the same plasmid extracted from escherichia coli transformed b. japonicum at v ...19902187405
rhizobitoxine inhibition of hydrogenase synthesis in free-living bradyrhizobium japonicum.rhizobitoxine produced by bradyrhizobium species strongly prevented derepression of hydrogenase expression in free-living bradyrhizobium japonicum, although the toxin had no effect on the activity of cells which had already synthesized hydrogenase protein. dihydrorhizobitoxine, a structural analog of rhizobitoxine, proved to be a less potent inhibitor of hydrogenase derepression. rhizobitoxine did not cause cell death at a concentration sufficient to eliminate hydrogenase expression. the large s ...19902198262
nickel accumulation and storage in bradyrhizobium japonicum.hydrogenase-derepressed (chemolithotrophic growth conditions) and heterotrophically grown cultures of bradyrhizobium japonicum accumulated nickel about equally over a 3-h period. both types of cultures accumulated nickel primarily in a form that was not exchangeable with nicl2, and they accumulated much more ni than would be needed for the ni-containing hydrogenase. the nickel accumulated by heterotrophically incubated cultures could later be mobilized to allow active hydrogenase synthesis durin ...19902200341
nitrogen fixation genes involved in the bradyrhizobium japonicum-soybean symbiosis.the symbiotic nitrogen fixation genes (nif, fix) of bradyrhizobium japonicum, the root nodule endosymbiont of soybean, are organized in at least two separate chromosomal gene clusters. these genes code for proteins of the nitrogenase complex, for proteins involved in their assembly with cofactors and for putative electron transport functions. one gene, nifa, codes for a transcriptional regulatory protein that plays a central role in the control of expression of the other genes in response to the ...19902200721
carbohydrate binding activities of bradyrhizobium japonicum. i. saccharide-specific inhibition of homotypic and heterotypic adhesion.bradyrhizobium japonicum (r110d) exhibited four saccharide-specific binding activities: (a) adsorption to sepharose beads containing covalently coupled lactose; (b) homotypic agglutination through one pole of the cell (star formation); (c) heterotypic adhesion to the cultured soybean cell line, sb-1; and (d) attachment to roots of soybean plants. each of these binding activities can be inhibited by the addition of galactose or lactose, but not by derivatives such as n-acetyl-d-galactosamine or m ...19902211829
carbohydrate binding activities of bradyrhizobium japonicum. ii. isolation and characterization of a galactose-specific lectin.extracts of bradyrhizobium japonicum were fractionated on sepharose columns covalently derivatized with lactose. elution of the material that was specifically bound to the affinity column with lactose yielded a protein of mr approximately 38,000. isoelectric focusing of this sample yielded two spots with pi values of 6.4 and 6.8. this protein specifically bound to galactose-containing glycoconjugates, but did not bind either to glucose or mannose. derivatives of galactose at the c-2 position sho ...19902211830
the identification, characterization, sequencing and mutagenesis of the genes (hupsl) encoding the small and large subunits of the h2-uptake hydrogenase of azotobacter chroococcum.the structural genes (hupsl) of the membrane-bound nife-containing h2-uptake hydrogenase (hup) of azotobacter chroococcum were identified by oligonucleotide screening and sequenced. the small subunit gene (hups) encodes a signal sequence of 34 amino acids followed by a 310-amino-acid, 34156d protein containing 12 cysteine residues. the large subunit gene (hupl) overlaps hups by one base and codes for a predicted 601-amino-acid, 66433d protein. there are two regions of strong homology with other ...19902215219
cytokine induction by lipopolysaccharide (lps) corresponds to lethal toxicity and is inhibited by nontoxic rhodobacter capsulatus lps.many pathological effects of gram-negative bacteria are produced by their cell wall-derived lipopolysaccharides (lpss). differing pathogenicity of gram-negative lpss, however, may depend on their capacities to induce cytokines. thus, we studied the lethal toxicity of four nonenterobacterial lpss and compared it with their capacity to induce mononuclear cell (mnc)-derived interleukin-1 (il-1), interleukin-6 (il-6), and tumor necrosis factor (tnf). unstimulated mnc did not release these cytokines. ...19902228245
fluorescence studies with malate dehydrogenase from bradyrhizobium japonicum 3i1b-143 bacteroids: a two-tryptophan containing protein.a number of fluorescence studies, both of trp residues and bound nadh, have been reported for porcine malate dehydrogenase (mdh). the large number of trp residues (six) complicates the interpretation of some studies. to circumvent this we have performed studies with a two-tryptophan (per subunit) mdh from bradyrhizobium japonicum 3i1b-143 bacteroids. we have performed phase/modulation fluorescence lifetime measurements, as a function of temperature and added quencher ki, in order to resolved the ...19902241162
ammonia regulation of nod genes in bradyrhizobium japonicum.the expression of the nodd and nodyabc operons of bradyrhizobium japonicum is repressed by the addition of ammonia. repression of nodyabc expression is probably due to the effect on nodd since nodd positively regulates itself, as well as other nod operons. the effect of ammonia is independent of the known nitrogen regulatory protein, ntrc, and another regulatory protein for nitrogen fixation, nifa.19902250656
cloning and sequence of the salmonella typhimurium heml gene and identification of the missing enzyme in heml mutants as glutamate-1-semialdehyde aminotransferase.salmonella typhimurium forms the heme precursor delta-aminolevulinic acid (ala) exclusively from glutamate via the five-carbon pathway, which also occurs in plants and some bacteria including escherichia coli, rather than by ala synthase-catalyzed condensation of glycine and succinyl-coenzyme a, which occurs in yeasts, fungi, animal cells, and some bacteria including bradyrhizobium japonicum and rhodobacter capsulatus. ala-auxotrophic heml mutant s. typhimurium cells are deficient in glutamate-1 ...19902254275
the nifen genes participating in femo cofactor biosynthesis and genes encoding dinitrogenase are part of the same operon in bradyrhizobium species.the nucleotide sequences of genes homologous to the klebsiella pneumoniae nifen genes have been determined in bradyrhizobium japonicum 110. the coding regions for the nife and nifn consist, respectively, of 1641 and 1407 nucleotides. the nifd gene (coding for the beta-subunit of dinitrogenase) and nife are linked, and separated by 95 nucleotides. in the region of 12 nucleotides that separates nife from nifn the stop codon for nife overlaps the putative ribosome binding site for nifn. in contrast ...19902266945
cell-associated oligosaccharides of bradyrhizobium spp.we report the initial characterization of the cell-associated oligosaccharides produced by four bradyrhizobium strains: bradyrhizobium japonicum usda 110, usda 94, and atcc 10324 and bradyrhizobium sp. strain 32h1. the cell-associated oligosaccharides of these strains were found to be composed solely of glucose and were predominantly smaller than the cyclic beta-1,2-glucans produced by agrobacterium and rhizobium species. linkage studies and nuclear magnetic resonance analyses demonstrated that ...19902294083
isolation and characterization of the lipopolysaccharides from bradyrhizobium japonicum.the lipopolysaccharide (lps) of bradyrhizobium japonicum 61a123 was isolated and partially characterized. phenol-water extraction of strain 61a123 yielded lps exclusively in the phenol phase. the water phase contained low-molecular-weight glucans and extracellular or capsular polysaccharides. the lpss from b. japonicum 61a76, 61a135, and 61a101c were also extracted exclusively into the phenol phase. the lpss from strain usda 110 and its nod- mutant hs123 were found in both the phenol and water p ...19902318801
proposed regulatory pathway encoded by the nodv and nodw genes, determinants of host specificity in bradyrhizobium japonicum.bradyrhizobium japonicum is the root nodule endosymbiont of soybean (glycine max), mung bean (vigna radiata), cowpea (vigna unguiculata), and siratro (macroptilium atropurpureum). we report the characteristics of a nodulation-gene region of b. japonicum that contributes only marginally to the bacterium's ability to nodulate soybean but is essential for the nodulation of the three alternative hosts. this dna region consists of two open reading frames designated nodv and nodw. the predicted amino ...19902320582
cloning and sequencing the genes encoding uptake-hydrogenase subunits of rhodocyclus gelatinosus.rhodocyclus gelatinosus grew photosynthetically in the light and consumed h2 at a rate of about 665 nmol/min per mg protein. the uptake-hydrogenase (h2ase) was found to be membrane bound and insensitive to inhibition by co. the structural genes of r. gelatinosus uptake-h2ase were isolated from a 40 kb cosmid gene library of r. gelatinosus dna by hybridization with the structural genes of uptake-h2ase of bradyrhizobium japonicum and rhodobacter capsulatus. the r. gelatinosus genes were localized ...19902325631
a model of nitrogen flow by malonamate in rhizobium japonicum-soybean symbiosis.two types of novel malonamidases were found in soybean nodules. one (e1) catalyzes the formation of malonamate from malonate and its hydrolysis to ammonia, whereas the other (e2) acts mainly on the hydrolysis of malonamate. e1 and e2 were found in bacteroids, but only e2 was found in the plant cytosol of the nodule. the substrate requirements of e1 and e2 were highly specific for malonate and malonamate, respectively. from these and other results reported previously, we propose that malonamate p ...19902357226
effects of the photobleaching herbicide, acifluorfen-methyl, on protoporphyrinogen oxidation in barley organelles, soybean root mitochondria, soybean root nodules, and bacteria.the photobleaching herbicide, acifluorfen-methyl (afm), has been reported to be an inhibitor of the heme and chlorophyll biosynthetic enzyme protoporphyrinogen oxidase (protox) in several plant species. however, afm had no effect on the levels of protox activity measured in a mitochondrial fraction from soybean roots. in contrast, afm inhibited protox activity in etioplasts from barley leaves and in mitochondria from barley roots, but the extent of inhibition varied depending upon the assay cond ...19902369128
genome analysis of bradyrhizobium japonicum serocluster 123 field isolates by using field inversion gel electrophoresis.the genomes of 11 bradyrhizobium japonicum serocluster 123 field isolates were analyzed by using field inversion gel electrophoresis. genomic fingerprints produced by digestion of intact genomic dna in agarose plugs with the rare-cutting restriction enzymes asei, drai, spei, and xbai showed that the isolates were genetically diverse. few (30 to 50%) isolates exhibited the same fingerprint as the usda serogroup strain with which they are antigenically related. southern hybridization with a nifhd ...19902383015
genetic organization of the hydrogen uptake (hup) cluster from rhizobium leguminosarum.in symbiosis with peas, rhizobium leguminosarum upm791 induces the synthesis of a hydrogen uptake (hup) system that recycles hydrogen generated in nodules by nitrogenase. a cosmid (pal618) containing hup genes from this strain on a 20-kilobase-pair (kb) dna insert has previously been isolated in our laboratory (a. leyva, j. m. palacios, t. mozo, and t.ruiz-argüeso, j. bacteriol. 169:4929-4934, 1987). here we show that cosmid pal618 contains all of the genetic information required to confer high ...19902407728
genetic analysis of the cytochrome c-aa3 branch of the bradyrhizobium japonicum respiratory chain.further genetic evidence is provided here that bradyrhizobium japonicum possesses a mitochondria-like electron-transport pathway: 2[h]----uq----bc1----c----aa3----o2. two tn5-induced mutants, cox122 and cox132, having cytochrome c oxidase-negative phenotypes, were obtained and characterized. mutant cox122 was defective in a novel gene, named cycm, which was responsible for the synthesis of a c-type cytochrome with an mr of 20,000 (20k). this 20k cytochrome c appeared to catalyse electron transpo ...19901965217
purification and properties of acetyl-coa synthetase from bradyrhizobium japonicum bacteroids.acetyl-coa synthetase was purified 800-fold from bradyrhizobium japonicum bacteroids. a specific activity of 16 mumol/min per mg of protein was achieved, with a 30-40% yield. the purification scheme consisted of only three consecutive chromatography steps. the enzyme has a native mr of 150,000, estimated by gel-permeation chromatography, and a subunit mr of 72,000, determined by sds/polyacrylamide-gel electrophoresis. the optimum ph and temperature are 8.5 and 50 degrees c respectively. the km v ...19901970239
molecular cloning, sequencing, and expression of the glutamine synthetase ii (glnii) gene from the actinomycete root nodule symbiont frankia sp. strain cpi1.in common with other plant symbionts, frankia spp., the actinomycete n2-fixing symbionts of certain nonleguminous woody plants, synthesize two glutamine synthetases, gsi and gsii. dna encoding the bradyrhizobium japonicum gene for gsii (glnii) hybridized to dna from three frankia strains. b. japonicum glnii was used as a probe to clone the glnii gene from a size-selected kpni library of frankia strain cpi1 dna. the region corresponding to the frankia sp. strain cpi1 glnii gene was sequenced, and ...19901975584
streptomyces hygroscopicus has two glutamine synthetase genes.streptomyces hygroscopicus, which produces the glutamine synthetase inhibitor phosphinothricin, possesses at least two genes (glna and glnb) encoding distinct glutamine synthetase isoforms (gsi and gsii). the glnb gene was cloned from s. hygroscopicus dna by complementation in an escherichia coli glutamine auxotrophic mutant (glna). glnb was subcloned in streptomyces plasmids by insertion into pij486 (pmsg3) and pij702 (pmsg5). both constructions conferred resistance to the tripeptide form of ph ...19901975585
periplasmic metabolism of glutamate and aspartate by intact bradyrhizobium japonicum bacteroids.in studies on the uptake and metabolism of [14c]glutamate by bradyrhizobium japonicum bacteroids we found that, in the presence of unlabeled malate, succinate or alpha-ketoglutarate, substantial label was recovered in alpha-ketoglutarate in the reaction mixtures. as much as 30% of the total 14c supplied could be found in alpha-ketoglutarate in the reaction mixtures after 30 min and this occurred in the absence of detectable labeling of alpha-ketoglutarate in the cells. the labeling of alpha-keto ...19901976384
persistence of introduced bradyrhizobium japonicum strains in forming nodules in subsequent years after inoculation in wisconsin soils.nodulation of soybeans by indigenous and inoculum strains of bradyrhizobium japonicum was studied in field experiments in wisconsin from 1983 to 86. aqueous suspensions of bacteria were applied to seeds at the time of planting at levels of 7 × 10(7)-10(10) bacteria per 2.5-cm row. the predominant indigenous serogroup was 123 in these soils. six different inoculum strains were used (two from serocluster 123, two from serogroup 110, and one each from serogroups 122 and c1). nodule occupants were i ...199022049940
detection of alternative nitrogenases in aerobic gram-negative nitrogen-fixing bacteria.strains of aerobic, microaerobic, nonsymbiotic, and symbiotic dinitrogen-fixing bacteria were screened for the presence of alternative nitrogenase (n2ase) genes by dna hybridization between genomic dna and dna encoding structural genes for components 1 of three different enzymes. a nifdk gene probe was used as a control to test for the presence of the commonly occurring mo-fe n2ase, a vnfdgk gene probe was used to show the presence of v-fe n2ase, and an anfdgk probe was used to detect fe n2ase. ...19911987127
the bradyrhizobium japonicum nola gene and its involvement in the genotype-specific nodulation of soybeans.several soybean genotypes have been identified which specifically exclude nodulation by members of bradyrhizobium japonicum serocluster 123. we have identified and sequenced a dna region from b. japonicum strain usda 110 which is involved in genotype-specific nodulation of soybeans. this 2.3-kilobase region, cloned in pmjs12, allows b. japonicum serocluster 123 isolates to form nodules on plants of serogroup 123-restricting genotypes. the nodules, however, were ineffective for symbiotic nitrogen ...19911988958
bradyrhizobium japonicum has two differentially regulated, functional homologs of the sigma 54 gene (rpon).recognition of -24/-12-type promoters by rna polymerase requires a special sigma factor, sigma 54 (rpon ntra glnf). in the nitrogen-fixing soybean symbiont bradyrhizobium japonicum, two functional, highly conserved rpon genes (rpon1 and rpon2) were identified and sequenced. the two predicted b. japonicum rpon protein sequences were 87% identical, and both showed different levels of homology to the rpon proteins of other bacteria. downstream of rpon2 (but not of rpon1), two additional open readin ...19911991712
novel organization of the common nodulation genes in rhizobium leguminosarum bv. phaseoli strains.nodulation by rhizobium, bradyrhizobium, and azorhizobium species in the roots of legumes and nonlegumes requires the proper expression of plant genes and of both common and specific bacterial nodulation genes. the common nodabc genes form an operon or are physically mapped together in all species studied thus far. rhizobium leguminosarum bv. phaseoli strains are classified in two groups. the type i group has reiterated nifhdk genes and a narrow host range of nodulation. the type ii group has a ...19911991718
the regulatory status of the fixl- and fixj-like genes in bradyrhizobium japonicum may be different from that in rhizobium meliloti.the cloning, sequencing and mutational analysis of the bradyrhizobium japonicum symbiotic nitrogen fixation genes fixl and fixj are reported here. the two genes were adjacent and probably formed an operon, fixlj. the predicted fixl and fixj proteins, members of the two-component sensor/regulator family, were homologous over almost their entire lengths to the corresponding rhizobium meliloti proteins (approx. 50% identity). downstream of the b. japonicum fixj gene was found an open reading frame ...19912000090
occurrence of lipid a variants with 27-hydroxyoctacosanoic acid in lipopolysaccharides from members of the family rhizobiaceae.lipopolysaccharides (lpss) isolated from several strains of rhizobium, bradyrhizobium, agrobacterium, and azorhizobium were screened for the presence of 27-hydroxyoctacosanoic acid. the lpss from all strains, with the exception of azorhizobium caulinodans, contained various amounts of this long-chain hydroxy fatty acid in the lipid a fractions. analysis of the lipid a sugars revealed three types of backbones: those containing glucosamine (as found in rhizobium meliloti and rhizobium fredii), tho ...19912007543
phylogeny of the phototrophic rhizobium strain btai1 by polymerase chain reaction-based sequencing of a 16s rrna gene segment.a 260-bp segment of the dna that encodes 16s rrna, corresponding to positions 44 to 337 in the escherichia coli sequence, was amplified by the polymerase chain reaction and sequenced from each of 13 bacteria (rhizobia and purple phototrophs) in the alpha subdivision of the class proteobacteria. the phylogenetic tree calculated from differences in the sequenced segment conforms well to our expectations based on other previously published data. the sequence from btai1 (a recently described phototr ...19912007551
identification of glya as a symbiotically essential gene in bradyrhizobium japonicum.a bradyrhizobium japonicum tn5 mutant (strain 3160) induced numerous, tiny, white nodules which were dispersed over the whole root system of its natural host plant, soybean (glycine max). these ineffective, nitrogen non-fixing pseudonodules were disturbed at a very early step of bacteroid and nodule development. subsequent cloning and sequencing of the dna region mutated in strain 3160 revealed that the tn5 insertion mapped in a gene that had 60% homology to the escherichia coli glya gene coding ...19912014004
cloning and nucleotide sequence of the hema gene of agrobacterium radiobacter.the hema gene of agrobacterium radiobacter atcc4718 was identified by hybridization with a hema probe from rhizobium meliloti and cloned by complementation of a hema mutant of escherichia coli k12. e. coli hema transformants carrying the hema gene of agrobacterium showed delta-aminolevulinic acid synthetase (delta-alas) activity in vitro. the hema gene was carried on a 4.4 kb ecori fragment which could be reduced to a 2.6 kb ecori-ssti fragment without affecting its complementing or delta-alas a ...19912034217
isoflavonoid-inducible resistance to the phytoalexin glyceollin in soybean rhizobia.the antibacterial effect of the soybean phytoalexin glyceollin was assayed using a liquid microculture technique. log-phase cells of bradyrhizobium japonicum and sinorhizobium fredii were sensitive to glyceollin. as revealed by growth rates and survival tests, these species were able to tolerate glyceollin after adaptation. incubation in low concentrations of the isoflavones genistein and daidzein induced resistance to potentially bactericidal concentrations of glyceollin. this inducible resista ...19912045365
influence of oxygen on dna binding, positive control, and stability of the bradyrhizobium japonicum nifa regulatory protein.central to the genetic regulatory circuit that controls bradyrhizobium japonicum nif and fix gene expression is the nifa protein. nifa activates transcription of several nif and fix genes and autoregulates its expression during symbiosis in soybean root nodules or in free-living microaerobic conditions. high o2 tensions result in the lack of nif expression, possibly by inactivation of nifa through oxidation of an essential metal cofactor. several b. japonicum nif and fix promoters have upstream ...19912045367
common cis-acting region responsible for transcriptional regulation of bradyrhizobium japonicum hydrogenase by nickel, oxygen, and hydrogen.bradyrhizobium japonicum expresses hydrogenase in microaerophilic free-living conditions in the presence of nickel. plasmid-borne hup-lacz transcriptional fusion constructs were used to study the regulation of the hydrogenase gene. the hydrogenase gene was transcriptionally induced under microaerobic conditions (0.1 to 3.0% partial pressure o2). the hydrogenase gene was not transcribed or was poorly transcribed in strictly anaerobic conditions or conditions above 3.0% o2. hydrogen gas at levels ...19912061281
nodules elicited by rhizobium meliloti heme mutants are arrested at an early stage of development.heme-deficient mutants of rhizobium and bradyrhizobium have been found to exhibit diverse phenotypes with respect to symbiotic interactions with plant hosts. we observed that r. meliloti hema mutants elicit nodules that do not contain intracellular bacteria; the nodules contain either no infection threads ("empty" nodule phenotype) or aberrant infection threads that failed to release bacteria (bar- phenotype). these mutant nodules expressed nodulin genes associated with nodules arrested at an ea ...19911766439
chemotaxis of bradyrhizobium japonicum to soybean exudates.the chemotactic response of bradyrhizobium japonicum toward soybean seed and root exudates was examined. assays using various isoflavones and fractionated exudate indicated that isoflavones are not the principal attractants in exudates. likewise, induction of nod genes with isoflavones or seed exudate before assay did not enhance chemotaxis. screening of numerous compounds revealed that only dicarboxylic acids and the amino acids glutamate and aspartate were strong attractants. the presence of g ...19911768137
molecular cloning of a gene region from bradyrhizobium japonicum essential for lipopolysaccharide synthesis.the gene region cloned from a lipopolysaccharide (lps) mutant carrying the tn5 and flanking dna sequences was used as a probe to screen a gene bank prepared from wild-type bradyrhizobium japonicum strain 61a101c and to isolate the corresponding wild-type lps-gene region. by cross-hybridization experiments the lps-gene region did not appear to be closely linked to previously cloned nodulation genes. a detailed restriction map of the lps-gene region (5.5-kb ecori genomic fragment) was established ...19911769537
identification of a nifa-like regulatory gene of azospirillum brasilense sp7 expressed under conditions of nitrogen fixation and in the presence of air and ammonia.a gene bank of azospirillum lipoferum br17 constructed in the vector lambda gem11 was screened with a bradyrhizobium japonicum nifa gene probe. a 7.3 kb ecori fragment carrying a nifa-like gene was thereby isolated and subsequently used to screen a gene bank of azospirillum brasilense sp7 constructed in puc18. two ecori fragments of 5.6 kb and 3.6 kb covering the nifa-homology region were found. mutants with nif- phenotype were obtained by site-directed tn5 mutagenesis of the 5.6 kb fragment and ...19911779763
identification of a locus within the hydrogenase gene cluster involved in intracellular nickel metabolism in bradyrhizobium japonicum.a 0.6-kb fragment of dna involved in intracellular ni metabolism was isolated and cloned from a cosmid containing 23.2 kb of hydrogenase-related genes of bradyrhizobium japonicum. this locus is located 8.3 kb upstream of the hydrogenase structural genes. the hydrogenase activity of a mutant with a gene-directed mutation at this locus (strain jhk7) showed dependency on nickel provided during hydrogenase derepression. the hydrogenase activity was only 20% of that in the wild-type strain, jh, at a ...19911785925
competitive inhibition of an energy-dependent nickel transport system by divalent cations in bradyrhizobium japonicum jh.both nickel-specific transport and nickel transport by a magnesium transporter have been described previously for a variety of nickel-utilizing bacteria. the derepression of hydrogenase activity in bradyzhizobium japonicum jh and in a gene-directed mutant of strain jh (in an intracellular ni metabolism locus), strain jhk7, was inhibited by mgso4. for both strains, ni2+ uptake was also markedly inhibited by mg2+, and the mg(2+)-mediated inhibition could be overcome by high levels of ni2+ provided ...19911785926
codon usage and g + c content in bradyrhizobium japonicum genes are not uniform.to date, the sequences of 45 bradyrhizobium japonicum genes are known. this provides sufficient information to determine their codon usage and g + c content. surprisingly, b. japonicum nodulation and nifa-regulated genes were found to have a less biased codon usage and a lower g + c content than genes not belonging to these two groups. thus, the coding regions of nodulation genes and nifa-regulated genes could hardly be identified in codon preference plots whereas this was not difficult with oth ...19911793334
structure and expression of the chlorobium vibrioforme hema gene.the green sulfur bacterium, chlorobium vibrioforme, synthesizes the tetrapyrrole precursor, delta-aminolevulinic acid (ala), from glutamate via the rna-dependent five-carbon pathway. a 1.9-kb clone of genomic dna from c. vibrioforme that is capable of transforming a glutamyl-trna reductase-deficient, ala-dependent, hema mutant of escherichia coli to prototrophy was sequenced. the transforming c. vibrioforme dna has significant sequence similarity to the e. coli, salmonella typhimurium, and bacil ...19911793335
a lipopolysaccharide mutant of bradyrhizobium japonicum that uncouples plant from bacterial differentiation.the tn5-containing fragment from a non-nodulating mutant of bradyrhizobium japonicum, strain ml142, was introduced into b. japonicum strain 61a101c by marker exchange to construct strain js314. strain js314 failed to nodulate several soybean varieties tested. however, on a few varieties nodulelike structures were induced to a frequency of 54% of the plants inoculated. the ultrastructure of these nodules was studied in detail by light and electron microscopy. the nodules were devoid of internal b ...19911799697
sequence and analysis of the nodabc region of rhizobium fredii usda257, a nitrogen-fixing symbiont of soybean and other legumes.we cloned and analyzed nodabc from rhizobium fredii usda257. these genes are thought to have common functions in initiation of nitrogen-fixing nodules by all rhizobia. in usda257, they were located in a 9.2-kb ecori fragment that was not closely linked to either of two copies of the regulatory gene, nodd. nodabc was present in a 3,094-base pair (bp) sequenced region, which also included a consensus nod-box promoter. the three open reading frames contained 654, 642, and 1,239 bp, respectively, an ...19911799701
repetitive sequences with homology to bradyrhizobium japonicum dna and the t-dna of agrobacterium rhizogenes are closely linked to nodabc of rhizobium fredii usda257.we have detected strong homology between a 9.2-kb ecori restriction fragment from rhizobium fredii usda257 that contains nodabc and eight additional ecori fragments in dna digests from this organism. a series of repetitive sequences responsible for this hybridization lies within a 0.95-kb hindiii/sali subfragment about 1-kb upstream of noda. this subfragment also hybridizes to multiple restriction fragments from nine other strains of r. fredii, but only one is common to all strains. the 0.95-kb ...19911799702
a novel membrane-bound glucosyltransferase from bradyrhizobium japonicum.bacteria within the family rhizobiaceae are distinguished by their ability to infect higher plants. the cell envelope carbohydrates of these bacteria are believed to be involved in the plant infection process. one class of cell envelope carbohydrate, the cyclic beta-1,2-glucans, is synthesized by species within two genera of this family, agrobacterium and rhizobium. in contrast, species of the genus bradyrhizobium, a third genus within this family, appear to lack the capacity for cyclic beta-1,2 ...19911829727
differential expression of phenylalanine ammonia-lyase and chalcone synthase during soybean nodule development.we have used conserved and nonconserved regions of cdna clones for phenylalanine ammonia-lyase (pal) and chalcone synthase (chs) isolated from a soybean-nodule cdna library to monitor the expression of members of the two gene families during the early stages of the soybean-bradyrhizobium japonicum symbiosis. our results demonstrate that subsets of the pal and chs gene families are specifically induced in soybean roots after infection with b. japonicum. furthermore, by analyzing a supernodulating ...19911840912
the genomes of the family rhizobiaceae: size, stability, and rarely cutting restriction endonucleases.the lack of high-resolution genetic or physical maps for the family rhizobiaceae limits our understanding of this agronomically important bacterial family. on the basis of statistical analyses of dna sequences of the rhizobiaceae and direct evaluation by pulsed-field agarose gel electrophoresis (pfe), five restriction endonucleases with at-rich target sites were identified as the most rarely cutting: asei (5'-attaat-3'), drai (5'-tttaaa-3'), spei (5'-actagt-3'), sspi (5'-aataat-3'), and xbai (5' ...19911846148
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
nucleotide sequence of the fixabc region of azorhizobium caulinodans ors571: similarity of the fixb product with eukaryotic flavoproteins, characterization of fixx, and identification of nifw.the nucleotide sequence of a 4.1 kb dna fragment containing the fixabc region of azorhizobium caulinodans was established. the three gene products were very similar to the corresponding polypeptides of rhizobium meliloti. the c-terminal domains of both fixb products displayed a high degree of similarity with the alpha-subunits of rat and human electron transfer flavoproteins, suggesting a role for the fixb protein in a redox reaction. two open reading frames (orf) were found downstream of fixc. ...19911850088
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
characterization of a soluble catalase-peroxidase hemoprotein b-590, previously identified as 'cytochrome alpha 1' from bradyrhizobium japonicum bacteroids.the cytochrome "a1" or p-428, previously proposed to be a high affinity terminal oxidase in nitrogen-fixing bacteroids of bradyrhizobium japonicum has been purified. the water-soluble native hemoprotein has an mr of 136,000, lacks heme a and is a high-spin ferric protohemoprotein: it is slowly reduced with dithionite to give a species with an optical spectrum like that of hemoprotein b-590 (escherichia coli; peak at 555 nm, shoulder at 590 nm), and which reacts slowly with co. it has catalase an ...19911645695
from one gene to two proteins: the biogenesis of cytochromes b and c1 in bradyrhizobium japonicum.genes coding for polyproteins that are cleaved posttranslationally into two or more functional proteins are rarely found in prokaryotes. one example concerns the biogenesis of the bradyrhizobium japonicum cytochromes b and c1, two of the three constituent subunits of ubiquinol-cytochrome-c reductase (ubiquinol:ferricytochrome-c oxidoreductase, ec 1.10.2.2); the respective apoproteins for these subunits are encoded by the 5' and 3' halves of a single gene, fbch. these two halves are linked by an ...19911647023
polygalacturonase is a virulence factor in agrobacterium tumefaciens biovar 3.agrobacterium tumefaciens biovar 3 causes both crown gall and root decay of grapes. all biovar 3 strains, regardless of their tumorigenicity, produce in culture a single polygalacturonase with a pi around 4.5. a. tumefaciens biovar 3 strain cg49 was mutagenized with tn5 by using psup2021 as a suicide vector. a mutant strain, cg50, lacking polygalacturonase activity was isolated. the mutation was due to a single tn5 insertion in an 8.5-kb ecori fragment that also contained the polygalacturonase s ...19911655716
the bradyrhizobium japonicum cycm gene encodes a membrane-anchored homolog of mitochondrial cytochrome c.mitochondrial cytochrome c is a water-soluble protein in the intermembrane space which catalyzes electron transfer from the cytochrome bc1 complex to the terminal oxidase cytochrome aa3. in bradyrhizobium japonicum, a gene (cycm) which apparently encodes a membrane-anchored homolog of mitochondrial cytochrome c was discovered. the apoprotein deduced from the nucleotide sequence of the cycm gene consists of 184 amino acids with a calculated mr of 19,098 and an isoelectric point of 8.35. at the n- ...19911657867
identification of a novel composite transposable element, tn5280, carrying chlorobenzene dioxygenase genes of pseudomonas sp. strain p51.analysis of one of the regions of catabolic plasmid pp51 which encode chlorobenzene metabolism of pseudomonas sp. strain p51 revealed that the tcba and tcbb genes for chlorobenzene dioxygenase and dehydrogenase are located on a transposable element, tn5280. tn5280 showed the features of a composite bacterial transposon with iso-insertion elements (is1066 and is1067) at each end of the transposon oriented in an inverted position. when a 12-kb hindiii fragment of pp51 containing tn5280 was cloned ...19911657878
characterization of cytochromes c550 and c555 from bradyrhizobium japonicum: cloning, mutagenesis, and sequencing of the c555 gene (cycc).the major soluble c-type cytochromes in cultured cells of bradyrhizobium japonicum usda 110 comprised a co-reactive c555 (mr, approximately 15,500) and a non-co-reactive c550 (mr, approximately 12,500). levels of cytochrome per gram of soluble protein in aerobic, anaerobic, and symbiotic cells were 32, 21, and 30 nmol, respectively, for c555 and 31, 44, and 65 nmol, respectively, for c550. the midpoint redox potentials (em,7) of the purified cytochromes were +236 mv for c555 and +277 mv for c550 ...19911660457
characterization of three soluble c-type cytochromes isolated from soybean root nodule bacteroids of bradyrhizobium japonicum strain cc705.three soluble, low molecular mass cytochromes c (mr 8000-15,000) were isolated and purified from soybean root nodule bacteroids of bradyrhizobium japonicum strain cc705. on the basis of their alpha: absorbance peaks in the reduced forms, they were named cytochromes c550, c552 and c555. cytochrome c552 reacted very fast, c555 very slowly and c550 not at all with carbon monoxide. the complete amino acid sequence (73 residues) of cytochrome c552 was established which identifies it as a monoheme, cl ...19911663887
cloning, sequencing and mutational analysis of the cytochrome c552 gene (cycb) from bradyrhizobium japonicum strain 110.we report the cloning and nucleotide sequence analysis of the cytochrome c552 gene (cycb) of bradyrhizobium japonicum strain 110. the gene was identified with help of an oligonucleotide that was designed on the basis of the amino acid sequence determined for purified cytochrome c552 of b. japonicum strain cc705. the cycb gene product has an n-terminal 23-amino acid signal peptide that is missing in the mature cytochrome c552 protein. a b. japonicum cycb insertion mutant was constructed which had ...19911663888
studies of the bradyrhizobium japonicum nodd1 promoter: a repeated structure for the nod box.induction of nod genes in rhizobium and bradyrhizobium species is dependent on the presence of plant-produced flavonoids, the nodd protein, and the cis-acting nod box promoter sequence. although the nodd (nodd1) gene in rhizobium species is constitutively expressed, nodd1 expression in bradyrhizobium japonicum is inducible by isoflavones in a manner similar to that of the nodyabc operon. a consensus nod box sequence is found 5' of the nodyabc operon, whereas a presumptive, nod box-like sequence ...19911675210
discovery of a rhizobial rna that is essential for symbiotic root nodule development.all of the azorhizobium, bradyrhizobium, and rhizobium genes known to be involved in the development of nitrogen-fixing legume root nodules are genes that code for proteins. here we report the first exception to this rule: the sra gene; it was discovered during the genetic analysis of a bradyrhizobium japonicum tn5 mutant (strain 259) which had a severe deficiency in colonizing soybean nodules. a dna region as small as 0.56 kb cloned from the parental wild type restored a wild-type phenotype in ...19911717438
16s rrna sequences of bartonella bacilliformis and cat scratch disease bacillus reveal phylogenetic relationships with the alpha-2 subgroup of the class proteobacteria.the primary structures of 16s rrnas of bartonella bacilliformis, an isolate of the cat scratch disease (csd) bacillus, and a strain phenotypically similar to the csd bacillus were determined by reverse transcriptase sequencing. these microorganisms were found to be members of the alpha-2 subgroup of the class proteobacteria. the sequence from b. bacilliformis was most closely related to the rrna of rochalimaea quintana (91.7% homology), the etiologic agent of trench fever. the sequence from the ...19911719021
chemotaxis and nod gene activity of bradyrhizobium japonicum in response to hydroxycinnamic acids and isoflavonoids.for bradyrhizobium japonicum, the chemotactic and the nod gene-inducing effects of hydroxycinnamic acids and two of their derivatives were compared with those of isoflavonoids. only the hydroxycinnamic acids were strong chemoattractants, while the other substances tested were chemotactically inactive. besides the known nod gene induction by isoflavonoids, a weak nod gene induction by coniferyl alcohol, chlorogenic acid, and ferulic acid was found.199116348401
symbiotic potential, competitiveness, and serological properties of bradyrhizobium japonicum indigenous to korean soils.the symbiotic potential of bradyrhizobium japonicum isolates indigenous to seven korean soils was evaluated by inoculating soybeans with 10- and 1,000-fold-diluted soil suspensions (whole-soil inocula). at both levels, significant differences in the symbiotic potential of the indigenous b. japonicum isolates were demonstrated. the relationship between rhizobial numbers in the whole-soil inocula (x) and nitrogen fixation parameters (y) was best predicted by a straight line (y = a + bx) when the n ...199116348454
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