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subgroups of the cowpea miscellany: symbiotic specificity within bradyrhizobium spp. for vigna unguiculata, phaseolus lunatus, arachis hypogaea, and macroptilium atropurpureum.rhizobia classified as bradyrhizobium spp. comprise a highly heterogeneous group of bacteria that exhibit differential symbiotic characteristics on hosts in the cowpea miscellany cross-inoculation group. to delineate the degree of specificity exhibited by four legumes in the cowpea miscellany, we tested the symbiotic characteristics of indigenous cowpea bradyrhizobia on cowpea (vigna unguiculata), siratro (macroptilium atropurpureum), lima bean (phaseolus lunatus), and peanut (arachis hypogaea). ...199116348492
biotransformation of the pentahydroxy flavone quercetin by rhizobium loti and bradyrhizobium strains (lotus).lotus rhizobia catabolized quercetin in an arabinose-based medium via a novel form of c-ring cleavage, yielding phloroglucinol and protocatechuic acid. conservation of the a and b rings of the flavone suggests that a chalcone could be formed as a transient intermediate.199116348495
phenotypic diversity among strains of bradyrhizobium japonicum belonging to serogroup 110.thirty-four strains of bradyrhizobium japonicum within serogroup 110 were examined for phenotypic diversity. the strains differed in their abilities to nodulate and fix dinitrogen with glycine max (l.) merr. cv. williams. thirteen strains expressed uptake hydrogenase activity when induced as free-living cultures in the presence of 2% hydrogen and oxygen. six bacteriophage susceptibility reactions were observed. each of the strains produced either a large, mucoid or a small, dry colony morphology ...199116348497
hydrogen oxidation by the host-controlled uptake hydrogenase phenotype of bradyrhizobium japonicum in symbiosis with soybean host plants.symbioses between uptake hydrogenase host-regulated (hup-hr) phenotypes of bradyrhizobium japonicum and exotic, agronomically unadapted soybean germ plasm were examined for expression of uptake hydrogenase activity. determinations for hydrogen evolution and uptake hydrogenase activity identified five plant introduction (pi) lines which formed hydrogen-oxidizing symbioses with strains usda 61 and pa3 6c. hup-hr strains belonging to serogroup 94 expressed uptake hydrogenase activity in symbioses w ...199116348518
efficiency of nodule initiation and autoregulatory responses in a supernodulating soybean mutant.we compared the formation of nodules on the primary roots of a soybean cultivar (glycine max (l.) merr. cv. bragg) and a supernodulating mutant derivative, nts382. inoculation with bradyrhizobium japonicum usda 110 at different times after seed imbibition showed that the roots acquired full susceptibility to infection only between 3 and 4 days postgermination. when the plants were inoculated with serial dilutions of a bacterial suspension, the number of nodules formed in the initially susceptibl ...199116348535
isolation and characterization of a competition-defective bradyrhizobium japonicum mutant.tn5 mutagenesis was coupled with a competition assay to isolate mutants of bradyrhizobium japonicum defective in competitive nodulation. a double selection procedure was used, screening first for altered extracellular polysaccharide production (nonmucoid colony morphology) and then for decreased competitive ability. one mutant, which was examined in detail, was deficient in acidic polysaccharide and lipopolysaccharide production. the wild-type dna region corresponding to the tn5 insertion was is ...199116348601
effect of inoculation and nitrogen on isoflavonoid concentration in wild-type and nodulation-mutant soybean roots.the isoflavones, daidzein and genistein, have been isolated and identified as the major inducers of nod genes of bradyrhizobium japonicum. the common nod genes of rhizobia are in turn responsible for stimulating root hair curling and cortical root cell division, the earliest steps in the host response. this study evaluated whether there was a relationship between root isoflavonoid production and the hypernodulation phenotype of selected soybean (glycine max [l.] merr.) mutants. three independent ...199116668002
effect of po(2) on the formation and status of leghemoglobin in nodules of cowpea and soybean.nodulated cowpea (vigna unguiculata [l.] walp. cv vita 3: bradyrhizobium strain cb756) and soybean (glycine max [l.] merr. cv white eye: bradyrhizobium strain cb1809) were grown with their root systems maintained in a flowing gas stream containing a range of po(2) (1-80%, v/v) in n(2) for up to 28 days after planting. at the extremes of sub- and supra-ambient po(2), the levels of leghemoglobin (lb) in nodules were reduced. however, neither the proportional composition of lb component proteins (e ...199116668046
effect of localized nitrate application on isoflavonoid concentration and nodulation in split-root systems of wild-type and nodulation-mutant soybean plants.although isoflavonoids are known to be inducers of nod genes in bradyrhizobium japonicum, it was recently proposed that internal root levels of isoflavonoids may be important in nodule development on soybean (glycine max [l.] merr.). the hypernodulating soybean mutants were shown to accumulate higher root concentrations of isoflavonoid compounds (daidzein, genistein, and coumestrol) and to be more extensively nodulated than was the williams parent when inoculated with b. japonicum. the hypernodu ...199116668097
effect of increases in oxygen concentration during the argon-induced decline in nitrogenase activity in root nodules of soybean.when intact nodulated roots of soybean (glycine max l. merr. nodulated with bradyrhizobium japonicum strain usda 16) were exposed to an atmosphere lacking n(2) gas (ar:o(2) 80:20), total nitrogenase activity (measured as h(2) evolution) and respiration (co(2) evolution) declined with time of exposure. in ar-inhibited nodules, when the o(2) concentration in the rhizosphere was increased in a linear ;ramp' of 2.7% per minute, 93% of the original h(2) evolution and 99% of the co(2) evolution could ...199116668196
adaptation of nodulated soybean (glycine max l. merr.) to growth in rhizospheres containing nonambient po(2).nodulated soybean (glycine max l. merr. cv white eye inoculated with bradyrhizobium japonicum strain cb 1809) plants were cultured in the absence of combined n from 8 to 28 days with their root systems maintained continuously in 1, 2.5, 5, 10, 20, 40, 60, or 80% o(2) (volume/volume) in n(2). plant dry matter yield was unaffected by partial pressure of oxygen (po(2)) and n(2) fixation showed a broad plateau of maximum activity from 2.5 to 40 or 60% o(2). slight inhibition of nitrogenase activity ...199116668248
root isoflavonoid response to grafting between wild-type and nodulation-mutant soybean plants.it was previously reported that the hypernodulating soybean (glycine max [l.] merr.) mutants, derived from the cultivar williams, had higher root concentration of isoflavonoid compounds (daidzein, genistein, and coumestrol) than did williams at 9 to 12 days after inoculation with bradyrhizobium japonicum. these compounds are known inducers of nod genes in b. japonicum and may be involved in subsequent nodule development. the current study involving reciprocal grafts between nod1-3 (hypernodulati ...199116668330
evidence for an inter-organismic heme biosynthetic pathway in symbiotic soybean root nodules.the successful symbiosis of soybean with bradyrhizobium japonicum depends on their complex interactions, culminating in the development and maintenance of root nodules. a b. japonicum mutant defective in heme synthesis in culture was able to produce heme as a result of its symbiotic association with the soybean host. the bacterial mutant was incapable of synthesizing the committed heme precursor delta-aminolevulinic acid (ala), but nodule plant cells formed ala from glutamate. in addition, exoge ...199117799282
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
gibberellins and the legume-rhizobium symbiosis : iii. quantification of gibberellins from stems and nodules of lima bean and cowpea.lima bean (phaseolus lunatus l.) plants inoculated with bradyrhizobium sp. strain 127e14 displayed a period of marked internode elongation that was not observed in plants inoculated with other compatible bradyrhizobia, including strain 127e15. when strain 127e14 nodulated an alternate host, cowpea (vigna unguiculata l. walp), a similar, although less dramatic growth response induced by the bacteria was observed. it has been speculated that the elongative growth promotion brought about by inocula ...199216653229
gibberellins and the legume-rhizobium symbiosis : i. endogenous gibberellins of lima bean (phaseolus lunatus l.) stems and nodules.the content of gibberellin-like substances in nodules formed by bradyrhizobium species strain 127e14 on roots of lima bean (phaseolus lunatus l.) has been previously found to be relatively high. the objectives of the present study were to purify and identify the endogenous gibberellins from the stems and nodules of lima bean. by sequential silica gel partition column chromatography, c(18) reverse-phase high performance liquid chromatography, and combined gas chromatography-mass spectrometry, the ...199216668617
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
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
bradyrhizobium populations occur in deep soil under the leguminous tree acacia albida.soil cores were drilled under the leguminous tree acacia albida growing in two different ecoclimatic zones of west africa: the sahelian area (100 to 500 mm of annual rainfall) and the sudano-guinean area (1,000 to 1,500 mm of annual rainfall). soil samples were collected at different depths from the surface down to the water table level and analyzed for the presence of rhizobia able to nodulate a. albida. in both areas, population densities of rhizobia were substantially greater near the water t ...199216348745
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
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
isolation and characterization of a ntrc mutant of bradyrhizobium (parasponia) sp. anu289.a mutant of bradyrhizobium (parasponia) sp. anu289 affected in the regulation of nitrogen metabolism was isolated. the mutant, designated anu293, was unable to induce ammonium transport (amt), nitrate reductase (nr) or glutamine synthetase ii (gsii) activities under conditions that induce these activities in the wild-type. however, glutamine synthetase i (gsi), which is expressed constitutively in the wild-type, was present at normal levels in the mutant. the mutant also retained the ability to ...19921353784
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
siderophore and organic acid production in root nodule bacteria.nineteen strains of root nodule bacteria were grown under various iron regimes (0.1, 1.0 and 20 microm added iron) and tested for catechol and hydroxamate siderophore production and the excretion of malate and citrate. the growth response of the strains to iron differed markedly. for 12 strains (bradyrhizobium strains nc92b and 32h1, b. japonicum usda110 and cb1809, b. lupini wu8, cowpea rhizobium ngr234, rhizobium meliloti strains u45 and cc169, rhizobium leguminosarum bv viciae wu235 and rhizo ...19921387306
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
[the growth of some bradyrhizobium strains in uremic conditions in the presence of antimicrobial substances].the growth rate of bradyrhizobium japonicum usda 110 and its strr and ampr mutant strains (resistant to streptomycin and ampicillin respectively), as well as tal 945 and tal 946, tal 947 (mutants of usda 110 and usda 138 respectively) on yeast extract mannitol agar (yema) containing different concentrations of crystal violet and brilliant green. according to our results only the growth of bacillus megaterium b17 was effected from crystal violet while the others were not effected from both of dye ...19921435367
signaling and host range variation in nodulation.rhizobium, bradyrhizobium, and azorhizobium strains, collectively referred to as rhizobia, elicit on their leguminous hosts, in a specific manner, the formation of nodules in which they fix nitrogen. rhizobial nod genes, which determine host specificity, infection, and nodulation, are involved in the exchange of low molecular weight signal molecules between the plant and the bacteria as follows. transcription of the nod operons is under the control of nodd regulatory proteins, which are specific ...19921444265
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
cell surface carbohydrates of microaerobic, nitrogenase-active, continuous cultures of bradyrhizobium sp. strain 32h1.a continuous culture system was developed to examine the cell surface carbohydrates of bradyrhizobium sp. strain 32h1. when cultures were shifted from aerobic to microaerobic growth conditions, nitrogenase activity was induced and extracellular polysaccharide levels were greatly reduced; however, the levels of cell-associated cyclic beta-1,6 -1,3 glucans were found to be essentially unchanged.19921447152
the rhizobium, bradyrhizobium, and azorhizobium nodc proteins are homologous to yeast chitin synthases.the nodabc genes of rhizobia are essential for the synthesis of lipo-oligosaccharidic (n-acylated chitin oligomers) nodulation signals. nodc gene products from rhizobium, bradyrhizobium, and azorhizobium exhibit extensive homology with chitin synthases, suggesting that the nodc proteins are involved in the synthesis of the chitin oligomer backbone by catalyzing the beta-1,4-linkage between n-acetyl-d-glucosamine residues.19921472721
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
conserved motifs in a divergent nod box of azorhizobium caulinodans ors571 reveal a common structure in promoters regulated by lysr-type proteins.nodulation of leguminous plants by rhizobium, bradyrhizobium, and azorhizobium spp. is dependent on the induction by the plant host of different bacterial nodulation (nod) loci. the transcription of these nod loci is activated in the presence of plant-produced flavonoids upon binding of the nodd protein--a lysr-type activator--to specific sequences present in the nod promoters. originally, a 47-base-pair (bp) region called the nod box was shown to be the target sequence for binding of nodd. from ...19921542656
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
detection and separation of rhizobium and bradyrhizobium nod metabolites using thin-layer chromatography.using radioactive acetate as a precursor, it was shown that the common nodabc genes of rhizobium and bradyrhizobium strains are involved in the production of one or more metabolites that are excreted into the growth medium. a rapid thin-layer chromatography (tlc) system has been developed to separate these so-called nod metabolites that can then be visualized by autoradiography. different patterns of nod metabolites were observed in the tested strains of the cross-inoculation groups of r. legumi ...19921600238
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
structural studies of a phosphocholine substituted beta-(1,3);(1,6) macrocyclic glucan from bradyrhizobium japonicum usda 110.in our previous in vivo 31p study of intact nitrogen-fixing nodules (rolin, d.b., boswell, r.t., sloger, c., tu, s.i. and pfeffer, p.e., 1989 plant physiol. 89, 1238-1246), we observed an unknown phosphodiester. the compound was also observed in the spectra of isolated bacteroids as well as extracts of the colonizing bradyrhizobium japonicum usda 110. in order to characterize the phosphodiester in the present study, we took advantage of the relatively hydrophobic nature of the material and purif ...19921610877
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
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
isolation and characterization of novel nodulin cdnas representing genes expressed at early stages of soybean nodule development.we took advantage of a subtractive hybridization procedure to isolate a set of cdna clones of nodule-specific genes (nodulin genes) from developing soybean root nodules. single-stranded 32p-labelled cdna synthesized from nodule poly(a)+ rna was hybridized with a large excess of uninfected root poly(a)+ rna. unhybridized cdna was selected and used to screen nodule cdna libraries. by this procedure we isolated several novel nodulin cdna clones together with most of the nodulin cdnas previously des ...19937683079
diversity of retron elements in a population of rhizobia and other gram-negative bacteria.genetic elements called retrons reside on the chromosome of escherichia coli and the myxobacteria and represent the first reverse transcriptase-encoding element to be found in a prokaryotic cell. all known retrons produce a functionally obscure rna-dna satellite molecule called multicopy single-stranded dna (msdna). we report here the presence of msdna-producing retron elements in a number of new bacterial groups, including strains of the genera proteus, klebsiella, salmonella, nannocystis, rhiz ...19937686549
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
[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
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
phylogenetic grouping and identification of rhizobium isolates on the basis of random amplified polymorphic dna profiles.through the use of a single, random 15mer as a primer, between 1 and 12 dna amplification products were obtained per strain from a selection of 84 rhizobium and bradyrhizobium isolates. a principal-coordinate analysis was used to analyse the resulting amplified dna profiles and it was possible to assign isolates to specific groupings. within the species rhizobium leguminosarum, the biovar phaseoli formed a distinct group from the other biovars of the species, viciae and trifolii, which grouped t ...19938364802
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
multiple copies of nodd in rhizobium tropici ciat899 and br816.rhizobium tropici strains are able to nodulate a wide range of host plants: phaseolus vulgaris, leucaena spp., and macroptilium atropurpureum. we studied the nodd regulatory gene for nodulation of two r. tropici strains: ciat899, the reference r. tropici type iib strain, and br816, a heat-tolerant strain isolated from leucaena leucocephala. a survey revealed several nodd-hybridizing dna regions in both strains: five distinct regions in ciat899 and four distinct regions in br816. induction experi ...19938419293
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
the oxygen sensor fixl of rhizobium meliloti is a membrane protein containing four possible transmembrane segments.regulation of nitrogen fixation genes in rhizobium meliloti is mediated by two proteins, fixl and fixj, in response to oxygen availability. fixl is an oxygen-binding hemoprotein with kinase and phosphatase activities that is thought to sense oxygen levels directly and to transmit this signal to fixj via phosphorylation-dephosphorylation reactions. fixj controls the expression of other regulatory genes, including nifa, that regulate the transcription of genes required for symbiotic nitrogen fixat ...19938432704
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
phylogenetic analysis of rhizobia and agrobacteria based on 16s rrna gene sequences.the phylogenetic relationships of members of the genera rhizobium, agrobacterium, bradyrhizobium, and azorhizobium were studied by direct sequencing of their amplified 16s rrna genes. comparative analysis of the sequence data confirmed that the genera bradyrhizobium and azorhizobium belong to distinct phylogenetic lineages. the genera rhizobium and agrobacterium were found to be phylogenetically heterogeneous, and several subgroupings in which rhizobium and agrobacterium species were intermixed ...19938494742
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
expression of antisense nodulin-35 rna in vigna aconitifolia transgenic root nodules retards peroxisome development and affects nitrogen availability to the plant.a nodulin-35 (n-35) cdna encoding nodule-specific uricase (ec 1.7.3.3.) was isolated from a vigna aconitifolia (mothbean) root nodule cdna library. sequence analysis of vigna uricase (vn-35) cdna revealed 90% homology to that of soybean. the vn-35 cdna was inserted in the antisense orientation downstream of the camv-35s promoter, and transgenic hairy roots were formed on vigna plants using agrobacterium rhizogenes. infection with bradyrhizobium (cowpea) gave rise to root nodules on transgenic ha ...19938220465
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
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