Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
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| cloning and sequence analysis of cych gene from paracoccus denitrificans: the cych gene product is required for assembly of all c-type cytochromes, including cytochrome c1. | a transposon tn5 mutant of paracoccus denitrificans, dp108, was incapable of anaerobic or methylotrophic growth and scored negative in the nadi cytochrome c oxidase test. p. denitrificans dp108 grown aerobically on succinate or choline was devoid of soluble c-type cytochromes and accumulated periplasmic apocytochrome c550, but the membrane-bound holocytochromes c1 and c552 were present at 5-10% of the levels observed in wild-type cells. dp108 genomic dna flanking the site of tn5 insertion was cl ... | 1995 | 7746152 |
| synthetic studies on the lipooligosaccharide nod bj-iv (c18:1, fuc, gro) produced by bradyrhizobium japonicum strain usda61. | 1995 | 7697654 | |
| the rhizobium-plant symbiosis. | rhizobium, bradyrhizobium, and azorhizobium species are able to elicit the formation of unique structures, called nodules, on the roots or stems of the leguminous host. in these nodules, the rhizobia convert atmospheric n2 into ammonia for the plant. to establish this symbiosis, signals are produced early in the interaction between plant and rhizobia and they elicit discrete responses by the two symbiotic partners. first, transcription of the bacterial nodulation (nod) genes is under control of ... | 1995 | 7708010 |
| the cychjkl gene cluster plays an essential role in the biogenesis of c-type cytochromes in bradyrhizobium japonicum. | we present an extended genetic analysis of the previously identified cych locus in bradyrhizobium japonicum. three new open reading frames found in an operon-like structure immediately adjacent to the 3' end of cych were termed cycj, cyck and cycl. a deletion mutant (delta cychjkl) and biochemical analysis of its phenotype showed that the genes of the cluster are essential for the biogenesis of cellular c-type cytochromes. mutations in discrete regions of each of the genes were also constructed ... | 1995 | 7715601 |
| the cychjkl genes of rhizobium meliloti involved in cytochrome c biogenesis are required for "respiratory" nitrate reduction ex planta and for nitrogen fixation during symbiosis. | we report the genetic and biochemical analysis of rhizobium meliloti mutants defective in symbiotic nitrogen fixation (fix-) and "respiratory" nitrate reduction (rnr-). the mutations were mapped close to the ade-1 and cys-46 chromosomal markers and the mutated locus proved to be identical to the previously described fix-14 locus. by directed tn5 mutagenesis, a 4.5 kb segment of the chromosome was delimited in which all mutations resulted in rnr- and fix- phenotypes. nucleotide sequence analysis ... | 1995 | 7715602 |
| the isolation and characterisation of a gene encoding superoxide dismutase from bradyrhizobium sp. (parasponia) strain anu289. | bradyrhizobium sp. (parasponia) strain anu289 expresses a single mn-sod in both the vegetative and symbiotic states. a 500 bp sod-homologous sequence was amplified from genomic dna of strain anu289 using pcr. a 1.3 kb sali fragment was subsequently cloned which contained an orf, soda, encoding a 23 kd protein. this putative sod shares considerable homology with other mn-sods and analysis of the soda sequence predicts that it is expressed. a lacz-soda fusion complemented the sod-deficiency of e. ... | 1995 | 8595379 |
| structural and functional analysis of the fixlj genes of rhizobium leguminosarum biovar phaseoli cnpaf512. | the fixlj genes of rhizobium leguminosarum biovar phaseoli cnpaf512 were identified by dna hybridization of a genomic library with an internal fragment of the rhizobium meliloti fixj gene. the nucleotide sequence was determined and the corresponding amino acid sequence was aligned with the amino acid sequences of the fixl proteins of r. meliloti, bradyrhizobium japonicum and azorhizobium caulinodans. while the fixj protein and the carboxy-terminal part of the fixl protein are highly homologous t ... | 1995 | 8552028 |
| metal sensitivity of some symbiotic n2-fixing bacteria and pseudomonas strains. | an investigation was carried out to determine the sensitivity of different soil microbes (rhizobium, bradyrhizobium and pseudomonas) to various metals (cu2+, zn2+, co2+, mn2+, mo2+ and fe2+) in vitro. sulphate and chloride forms of these microelements were used (except mo2+ as na2mo04) in 0.1, 1.0 and 10 micrograms/ml concentrations in modified yem and nutrient broth. growth (optical density, od550 and od640) of bacterium inoculated (approx. 10(6) cfu/ml) tubes, was measured spectrophotometrical ... | 1995 | 8714759 |
| a tnphoa insertion within the bradyrhizobium japonicum sips gene, homologous to prokaryotic signal peptidases, results in extensive changes in the expression of pbm-specific nodulins of infected soybean (glycine max) cells. | bradyrhizobium japonicum mutant 132 was obtained by random tnphoa mutagenesis of strain 110spc4. a 6.5 kb bamhi kanamycin-resistance-coding dna fragment of mutant 132 was used as a hybridization probe to clone the corresponding wild-type fragment. dna sequence analysis of a 3213 bp bamhi-clai fragment revealed that three open reading frames (orfs) were encoded in the same orientation. based on sequence similarities to other proteins in the database, the second orf was called sips (signal peptida ... | 1995 | 8825087 |
| fate of nodule-specific polysaccharide produced by bradyrhizobium japonicum bacteroids. | a polysaccharide produced by bradyrhizobium japonicum bacteroids in nodules (nps) on soybean (glycine max [l.] merr.) roots is different in composition and structure from the extracellular polysaccharide produced in culture by this organism. isogenic strains either capable or incapable of nps synthesis supported similar rates of plant growth and nitrogenase activity, indicating that polysaccharide deposition was not detrimental. the possibility that nps may have some protective or nutritional ro ... | 1995 | 12228408 |
| preincubation of bradyrhizobium japonicum with genistein accelerates nodule development of soybean at suboptimal root zone temperatures. | in the soybean (glycine max [l.] merr.) n2-fixing symbiosis, suboptimal root zone temperatures (rzts) slow nodule development, especially at temperatures below 17[deg]c. a step in the infection process that occurs within the first 24 h is particularly sensitive to suboptimal rzt. the first phase in the establishment of the soybean-bradyrhizobium japonicum symbiosis is the exchange of recognition molecules. the most effective plant-to-bacterium signal is genistein. binding of genistein to b. japo ... | 1995 | 12228519 |
| rhizobial nodulation factors stimulate mycorrhizal colonization of nodulating and nonnodulating soybeans. | legumes form tripartite symbiotic associations with noduleinducing rhizobia and vesicular-arbuscular mycorrhizal fungi. co-inoculation of soybean (glycine max [l.] merr.) roots with bradyrhizobium japonicum 61-a-101 considerably enhanced colonization by the mycorrhizal fungus glomus mosseae. a similar stimulatory effect on mycorrhizal colonization was also observed in nonnodulating soybean mutants when inoculated with bradyrhizobium japonicum and in wild-type soybean plants when inoculated with ... | 1995 | 12228558 |
| the rhizobial hema gene is required for symbiosis in species with deficient [delta]-aminolevulinic acid uptake activity. | most rhizobial hema mutants induce root nodules on their respective legume hosts that lack nitrogen fixation activity and leghemoglobin expression. however, a bradyrhizobium japonicum hema mutant elicits effective nodules on soybean, and we proposed previously that synthesis and uptake of the heme precursor [delta]-aminolevulinic acid (ala) by the plant and bacterial symbiont, respectively, allow mutant rescue (i. sangwan, m.r. o'brian [1991] science 251: 1220-1222). in the present work, the b. ... | 1995 | 12228561 |
| restriction of nodulation by bradyrhizobium japonicum is mediated by factors present in the roots of glycine max. | reciprocal grafting experiments done using soybean plant introduction genotypes indicated that restriction of nodulation by bradyrhizobium japonicum is determined by the genotype of the root and is dependent on plant growth temperature. microscopic analyses indicated that the soybean plant introduction genotypes restrict nodulation of b. japonicum at symbiotic stages which occur both before and after the formation of nodule primordia. | 1995 | 16534946 |
| diversity among field populations of bradyrhizobium japonicum in poland. | genetic structure in field populations of bradyrhizobium japonicum isolated in poland was determined by using several complementary techniques. of the 10 field sites examined, only 4 contained populations of indigenous b. japonicum strains. the polish bradyrhizobia were divided into at least two major groups on the basis of protein profiles on polyacrylamide gels, serological reaction with polyclonal antisera, repetitive extragenic palindromic pcr fingerprints of genomic dna, and southern hybrid ... | 1995 | 16534985 |
| host-controlled restriction of nodulation by bradyrhizobium japonicum strains in serogroup 110. | we previously reported the identification of a soybean plant introduction (pi) genotype, pi 417566, which restricts nodulation by bradyrhizobium japonicum mn1-1c (usda 430), strains in serogroup 129, and usda 110 (p. b. cregan, h. h. keyser, and m. j. sadowsky, appl. environ. microbiol. 55:2532-2536, 1989, and crop sci. 29:307-312, 1989). in this study, we further characterized nodulation restriction by pi 417566. twenty-four serogroup 110 isolates were tested for restricted nodulation on pi 417 ... | 1995 | 16535054 |
| protein synthesis by bradyrhizobium japonicum bacteroids declines as a function of nodule age. | isolated bacteroids of bradyrhizobium japonicum accumulated exogenously supplied [(sup35)s]methionine or [(sup3)h]leucine and incorporated them into cytosolic proteins. the accumulation of these labeled amino acids was inhibited by azide. only 3 to 6% of these accumulated amino acids were incorporated into protein. protein synthesis was not stimulated by incubation of bacteroids in the presence of potassium salts, malate, or amino acids, but azide, chloramphenicol, and acridine did inhibit the p ... | 1996 | 16535424 |
| enzymes of poly-(beta)-hydroxybutyrate metabolism in soybean and chickpea bacteroids. | the enzymatic capacity for metabolism of poly-(beta)-hydroxybutyrate (phb) has been examined in nitrogen-fixing symbioses of soybean (glycine max l.) plants, which may accumulate substantial amounts of phb, and chickpea (cicer arietinum l.) plants, which contain little or no phb. in the free-living state, both bradyrhizobium japonicum cb 1809 and rhizobium sp. (cicer) cc 1192, which form nodules on soybean and chickpea plants, respectively, produced substantial amounts of phb. to obtain informat ... | 1996 | 16535445 |
| total glutamine synthetase activity during soybean nodule development is controlled at the level of transcription and holoprotein turnover. | gln synthetase (gs) catalyzes the atp-dependent condensation of ammonia with glutamate to yield gln. in higher plants gs is an octameric enzyme and the subunits are encoded by members of a small multigene family. in soybeans (glycine max), following the onset of n2 fixation there is a dramatic increase in gs activity in the root nodules. gs activity staining of native polyacrylamide gels containing nodule and root extracts showed a common band of activity (gsrs). the nodules also contained a slo ... | 1996 | 12226474 |
| histidine 131, not histidine 43, of the bradyrhizobium japonicum fixn protein is exposed towards the periplasm and essential for the function of the cbb3-type cytochrome oxidase. | in subunit i (fixn) of the bradyrhizobium japonicum cbb3-type oxidase, only five instead of the normal six strictly conserved histidines (h) could be unambiguously assigned as the putative heme or copper ligands. the ambiguity concerned h43 or h131 as the presumptive n-terminal ligands of the low-spin heme b. we report here that a h43a replacement had a wild-type phenotype, whereas the h131a mutant was defective in oxidase function and subunit assembly or stability, suggesting that h131 serves a ... | 1996 | 8830672 |
| the hydrogenase gene cluster of rhizobium leguminosarum bv. viciae contains an additional gene (hypx), which encodes a protein with sequence similarity to the n10-formyltetrahydrofolate-dependent enzyme family and is required for nickel-dependent hydrogenase processing and activity. | plasmid pal618 contains the genetic determinants for h2 uptake (hup) from rhizobium leguminosarum bv. viciae, including a cluster of 17 genes named hupslcdefghijk-hypabfcde. a 1.7-kb segment of insert dna located downstream of hype has now been sequenced, thus completing the sequence of the 20441-bp insert dna in plasmid pal618. an open reading frame (designated hypx) encoding a protein with a calculated m(r) of 62300 that exhibits extensive sequence similarity with hoxx from alcaligenes eutroph ... | 1996 | 8842143 |
| nodz of bradyrhizobium extends the nodulation host range of rhizobium by adding a fucosyl residue to nodulation signals. | the nodulation genes of rhizobia are involved in the production of the lipo-chitin oligosaccharides (lco), which are signal molecules required for nodule formation. a mutation in nodz of bradyrhizobium japonicum results in the synthesis of nodulation signals lacking the wild-type 2-o-methylfucose residue at the reducting-terminal n-acetylglucosamine. this phenotype is correlated with a defective nodulation of siratro (macroptilium atropurpureum). here we show that transfer of nodz to rhizobium l ... | 1996 | 8858593 |
| modulation of carbohydrate-binding capacities and attachment ability of bradyrhizobium sp. (lupinus) to white lupin roots. | the attachment of bradyrhizobium sp. (lupinus) strain msdj718 to excised roots of white lupin was examined. maximal attachment occurred at early to middle log phases of bacterial growth. this binding was ph dependent, with an optimal value reached at 6.6. irrespective of the culture age, the attachment was strongly affected by the calcium concentration of the growth medium: a ca2+ limitation in the bergersen medium led to optimal attachment of the bacteria. when l-fucose was added during the att ... | 1996 | 8868230 |
| activity of nitrogen fixation and nitrogen assimilation enzymes in soybean plants inoculated with bradyrhizobium japonicum strains. | in studying the symbiotic associations of 8 bradyrhizobium japonicum strains with two soybean varieties (ns-10 and ns-21), we determined the activity of nitrogen fixing (nitrogenase, ng) and nitrogen assimilation (glutamine synthetase, gs) and glutamate dehydrogenase (gdh) enzymes and the content of soluble proteins. the number of nodules was not in correlation with dry matter mass and nitrogen content. dry matter mass and nitrogen content in the nodules of the soybean varieties in association w ... | 1996 | 8876729 |
| a cytochrome c biogenesis gene involved in pyoverdine production in pseudomonas fluorescens atcc 17400. | pseudomonas fluorescens atcc 17400 produces pyoverdine under iron-limiting conditions. a tn5 mutant, 2g11, produced lower amounts of different pyoverdine forms and was unable to grow under iron limitation caused by ethylenediamine-di(o-hydroxy-phenylacetic acid) (eddha) or zinc. this mutant was complemented by a 9.6 kb hindiii-bamhi dna fragment that contained eight contiguous open reading frames (orfs cyta to cyth). the proteins possibly encoded by this polycistronic gene cluster were all simil ... | 1996 | 8878040 |
| the bradyrhizobium japonicum aconitase gene (acna) is important for free-living growth but not for an effective root nodule symbiosis. | the bradyrhizobium japonicum acna gene encoding the tricarboxylic acid cycle enzyme aconitase was cloned and characterized. the gene was mapped immediately upstream of the cytochrome c biogenesis gene cycv and found to be transcribed in the opposite direction. the nucleotide sequence of acna was determined; the derived amino acid sequence shared a significant similarity with bacterial aconitases and with the human iron-responsive-element-binding protein. the level of expression of the acna gene ... | 1996 | 8892815 |
| the genetic and biochemical basis for nodulation of legumes by rhizobia. | soil bacteria of the genera azorhizobium, bradyrhizobium, and rhizobium are collectively termed rhizobia. they share the ability to penetrate legume roots and elicit morphological responses that lead to the appearance of nodules. bacteria within these symbiotic structures fix atmosphere nitrogen and thus are of immense ecological and agricultural significance. although modern genetic analysis of rhizobia began less than 20 years ago, dozens of nodulation genes have now been identified, some in m ... | 1996 | 8935908 |
| genetic diversity among bradyrhizobium isolates that effectively nodulate peanut (arachis hypogaea). | symbiotic gene diversity and other measures of genetic diversity were examined in bradyrhizobium isolates that form an effective symbiosis with peanut (arachis hypogaea). initially, restriction fragment length polymorphism (rflp) analysis using a nitrogenase (nif) gene probe was performed on 33 isolates along with one bradyrhizobium elkanii and two bradyrhizobium japonicum strains. considerable diversity was observed among the rflp patterns of many of the isolates, especially those from south am ... | 1996 | 8941988 |
| the bradyrhizobium japonicum fega gene encodes an iron-regulated outer membrane protein with similarity to hydroxamate-type siderophore receptors. | iron is important in the symbiosis between soybean and its nitrogen-fixing endosymbiont bradyrhizobium japonicum, yet little is known about rhizobial iron acquisition strategies. analysis of outer membrane proteins (omps) from b. japonicum 61a152 identified three iron-regulated omps in the size range of several known receptors for fe(iii)-scavenging siderophores. one of the iron-regulated proteins, fega, was purified and microsequenced, and a reverse genetics approach was used to clone a fega-co ... | 1996 | 8955412 |
| the huptuv operon is involved in negative control of hydrogenase synthesis in rhodobacter capsulatus. | the hupt, hupu, and hupv genes, which are located upstream from the hupslc and hypf genes in the chromosome of rhodobacter capsulatus, form the huptuv operon expressed from the hupt promoter. the hupu and hupv genes, previously thought to belong to a single open reading frame, encode hupu, of 34.5 kda (332 amino acids), and hupv, of 50.4 kda (476 amino acids), which are >/= 50% identical to the homologous bradyrhizobium japonicum hupu and hupv proteins and rhodobacter sphaeroides hupu1 and hupu2 ... | 1996 | 8752335 |
| sequence and mutational analysis of the common nodbcij region of rhizobium sp. (oxytropis arctobia) strain n33, a nitrogen-fixing microsymbiont of both arctic and temperate legumes. | by heterologous hybridization, we have identified the common nodulation genes nodbcij of rhizobium sp. strain n33 within a 8.2-kb psti fragment. the nodbcij genes are located within a 4,620-bp region which also included a consensus nod box promoter. the four open reading frames coding for the nodbcij genes contain 657, 1,353, 915, and 789 nucleotides, respectively. we found that the noda gene was not adjacent to the nodb gene, unlike the situation in many rhizobia. the dna of the nodbcij genes o ... | 1996 | 8755627 |
| beta-glucan synthesis in bradyrhizobium japonicum: characterization of a new locus (ndvc) influencing beta-(1-->6) linkages. | bradyrhizobium japonicum synthesizes periplasmic cyclic beta-(1-->3),beta-(1-->6)-d-glucans during growth in hypoosmotic environments, and evidence is growing that these molecules may have a specific function during plant-microbe interactions in addition to osmoregulation. site-directed tn5 mutagenesis of the dna region upstream of ndvb resulted in identification of a new gene (ndvc) involved in beta-(1--> 3), beta-(1-->6)-glucan synthesis and in nodule development. the predicted translation pro ... | 1996 | 8755895 |
| expression of the early nodulin, enod40, in soybean roots in response to various lipo-chitin signal molecules. | the lipo-chitin (lco) nodulation signal (nod signal) purified from bradyrhizobium japonicum induced nodule primordia on soybean (i.e. glycine soja) roots. these primordia were characterized by a bifurcated vascular connection, cortical cell division, and the accumulation of mrna of the early nodulin gene, enod40. a chemically synthesized lco identical in structure to the nod signal purified from b. japonicum cultures showed the same activity when inoculated on to soybean roots. surprisingly, syn ... | 1996 | 8758977 |
| purification and characterization of the membrane-bound nitrate reductase isoenzymes of bradyrhizobium japonicum. | two respiratory membrane-bound nitrate reductase (nr) isoenzymes, nri and nrii, have been purified for the first time from one single microorganism. triton x-100-solubilized nrs were purified by a three-step procedure of differential centrifugation, q-sepharose chromatography, and gel filtration on sephacryl s-300. both isoenzymes were purified to homogeneity by the criteria of nr activity staining in polyacrylamide gels run under non-denaturating conditions and coincident staining of the protei ... | 1996 | 8769303 |
| the bradyrhizobium japonicum rpoh1 gene encoding a sigma 32-like protein is part of a unique heat shock gene cluster together with groesl1 and three small heat shock genes. | the heat shock response of bradyrhizobium japonicum is controlled by a complex network involving two known regulatory systems. while some heat shock genes are controlled by a highly conserved inverted-repeat structure (circe), others depend on a sigma 32-type heat shock sigma factor. using western blot (immunoblot) analysis, we confirmed the presence of a sigma 32-like protein in b. japonicum and defined its induction pattern after heat shock. a b. japonicum rpoh-like gene (rpoh1) was cloned by ... | 1996 | 8808920 |
| nodule development induced by mutants of bradyrhizobium japonicum defective in cyclic b-glucan synthesis. | the soybean response to inoculation with b. japonicum mutants defective in cyclic beta-(1-->3), beta-(1-->6) glucan synthesis was examined by electron microscopy and by monitoring the expression of early and late nodulin genes. two mutants were examined. strain ab-14 is an ndvb mutant and is unable to synthesize beta-glucans. strain ab-1 is an ndvc mutant and produces cyclic glucans containing 95 to 100% beta-(1-->3) glycosidic linkages. nodules formed by either mutant were defective in nitrogen ... | 1996 | 8810069 |
| phenotypic characterization and regulation of the nola gene of bradyrhizobium japonicum. | two bradyrhizobium japonicum nola mutants were constructed and used to test the functional role of nola in nodulation. contrary to the previous hypothesis that nola acts as a repressor of nod gene transcription, the expression of a nodd1-lacz or nody-lacz fusion in the nola mutant strains was similar to that found in the wild type. however, nola does appear to act as a transcriptional regulatory protein since it is required for its own expression, as well as that of nodd2. expression of nodd2 fr ... | 1996 | 8810078 |
| two different mechanisms are involved in the heat-shock regulation of chaperonin gene expression in bradyrhizobium japonicum. | heat-shock regulation was detected for three out of the five members of the groesl multigene family in bradyrhizobium japonicum. the results uncovered the simultaneous presence of two distinct heat-shock control systems which so far have not been reported to co-exist in a single prokaryotic organism. the first system concerns groesl1 whose transcription is controlled in a sigma32-dependent manner similar to that known from work done with escherichia coli. heat-shock control of groesl4 is mediate ... | 1996 | 8820652 |
| the cytochrome bc1 complex but not cycm is necessary for symbiotic nitrogen fixation by rhizobium leguminosarum. | following tn5 mutagenesis of rhizobium leguminosarum biovar viciae, two mutants in one complementation group were identified as being unable to fix nitrogen in pea nodules. spectroscopic analysis revealed that the mutants had lowered levels of c-type cytochromes and cytochromes aa3, but increased levels of cytochrome d. cells of the mutants were greatly reduced in their ability to oxidize the artificial electron donor n,n,n',n'-tetramethyl-p-phenylenediamine but membranes prepared from them had ... | 1996 | 9004501 |
| cyclolaminarinose. a new biologically active beta-(1-->3) cyclic glucan. | a unique glucan has been isolated from a recombinant strain of a rhizobium meliloti ty7, a cyclic beta-(1-->2) glucan mutant carrying a locus specifying beta-(1-->3; 1-->6) glucan synthesis from bradyrhizobium japonicum usda110. this compound, which appears to have considerable hydrophobic affinity, was separated from a perchloric acid cell extract by adsorption to a c-18 silica column. unlike those cyclic glucans previously isolated from rhizobium meliloti or bradyrhizobium japonicum, this mole ... | 1996 | 9008841 |
| genetic variability of the common nod gene in soybean bradyrhizobia isolated in thailand and japan. | to determine the taxonomic relationship between thai soybean bradyrhizobia and soybean bradyrhizobia from other regions, a total of 62 bradyrhizobium strains were isolated in thailand. the genetic diversity of the strains was examined with reference to 46 japanese and 15 usda strains. the degree of sequence divergence in and around common nod gene regions of the 123 strains was estimated by restriction fragment length polymorphism analysis using the bradyrhizobium japonicum usda 110 common noddy ... | 1996 | 8989861 |
| cloning and sequencing of the nitrogenase structural genes nifhdk of herbaspirillum seropedicae. | the nitrogenase structural genes (nifhdk) of the endophytic diazotroph herbaspirillum seropedicae were isolated from a genomic bank by plate hybridization. sequence analysis of the dna showed a consensus promoter region upstream for the nifh gene containing a -24/-12 type promoter together with nifa- and integration host factor (ihf)- binding sites. the derived protein sequences of nifh, nifd and nifk contained conserved cysteine residues for binding iron-sulfur clusters and the iron-molybdenum ... | 1996 | 9222418 |
| the bradyrhizobium japonicum coxwxyz gene cluster encodes a bb3-type ubiquinol oxidase. | bradyrhizobium japonicum, a symbiotic nitrogen-fixing bacterium, has a complex respiratory electron-transport chain, capable of functioning throughout a wide range of oxygen tensions. it does so by synthesizing a number of terminal oxidases, each appropriate for different environmental conditions. we have previously described the cloning of the large catalytic subunit, coxx, from one of the terminal oxidases from b. japonicum [surpin, m.a., moshiri, f., murphy, a.m. and maier, r.j. (1994) geneti ... | 1996 | 8996107 |
| isolation, dna sequence analysis, and mutagenesis of a proline dehydrogenase gene (puta) from bradyrhizobium japonicum. | we report here the cloning and sequencing of the gene for proline dehydrogenase (puta) of bradyrhizobium japonicum. an open reading frame coding for 1,016 amino acids was identified. the b. japonicum gene codes for a bifunctional protein with proline dehydrogenase and pyrroline-5-carboxylate (p5c) dehydrogenase activities, as it does in escherichia coli and salmonella typhimurium. comparison of the sequences of these proteins with other proline and p5c dehydrogenase sequences identified proline ... | 1996 | 8572700 |
| levels and identities of nonrhizobial microorganisms found in commercial legume inoculant made with nonsterile peat carrier. | sixty samples of commercial north american legume inoculants manufactured for sale in 1994 using nonsterile peat as carrier were tested for rhizobium (or bradyrhizobium) content and non-rhizobium biological contaminant load. products of three major producers of such inoculants for sale in canada were examined. viable rhizobium content varied from 5.6 x 10(5) to 8.1 x 10(9) cells/g, while the contaminant load varied from 1.8 x 10(8) to 5.5 x 10(10) cfu/g. most of the inoculants contained more non ... | 1996 | 8595599 |
| bradyrhizobium japonicum possesses two discrete sets of electron transfer flavoprotein genes: fixa, fixb and etfs, etfl. | a group of four co-regulated genes (fixa, fixb, fixc, fixx) essential for symbiotic nitrogen fixation has been described in several rhizobial species, including bradyrhizobium japonicum. the complete nucleotide sequence of the b. japonicum fixa, fixb and fixc, genes is reported here. the derived amino acid sequences confirmed the previously noted sequence similarity between fixa and the beta-subunit and between fixb and the alpha-subunit of mammalian and paracoccus denitrificans electron transfe ... | 1996 | 8599534 |
| bradyrhizobium japonicum porphobilinogen synthase uses two mg(ii) and monovalent cations. | bradyrhizobium japonicum porphobilinogen synthase (b. japonicum pbgs) has been purified and characterized from an overexpression system in an escherichia coli host (chauhan, s., and o'brian, m. r. (1995) j. biol. chem. 270, 19823-19827). b. japonicum pbgs defines a new class of pbgs protein, type iv (classified by metal ion content), which utilizes a catalytic mga present at a stoichiometry of 4/octamer, an allosteric mgc present at a stoichiometry of 8/octamer, and a monovalent metal ion, k+. h ... | 1996 | 8621501 |
| assembly and function of the cytochrome cbb3 oxidase subunits in bradyrhizobium japonicum. | the bradyrhizobium japonicum cbb3-type cytochrome oxidase, which supports microaerobic respiration, is a multisubunit enzyme encoded by the genes of the fixnoqp operon. we investigated the contribution of the individual subunits to function and assembly of the membrane-bound complex. in-frame deletion mutants of fixn, fixo, and fixq, and an insertion mutant of fixp were constructed. all mutants, except the fixq mutant, showed clearly altered absorption difference spectra of their membranes and d ... | 1996 | 8621562 |
| a high-affinity cbb3-type cytochrome oxidase terminates the symbiosis-specific respiratory chain of bradyrhizobium japonicum. | it has been a long-standing hypothesis that the endosymbiotic rhizobia (bacteroids) cope with a concentration of 10 to 20 nm free o2 in legume root nodules by the use of a specialized respiratory electron transport chain terminating with an oxidase that ought to have a high affinity for o2. previously, we suggested that the microaerobically and anaerobically induced fixnoqp operon of bradyrhizobium japonicum might code for such a special oxidase. here we report the biochemical characteristics of ... | 1996 | 8626278 |
| rhizobium nodulation protein noda is a host-specific determinant of the transfer of fatty acids in nod factor biosynthesis. | in the biosynthesis of lipochitin oligosaccharides (lcos) the rhizobium nodulation protein noda plays an essential role in the transfer of an acyl chain to the chitin oligosaccharide acceptor molecule. the presence of noda in the nodabcij operon makes genetic studies difficult to interpret. in order to be able to investigate the biological and biochemical functions of noda, we have constructed a test system in which the noda, nodb and nodc genes are separately present on different plasmids. effi ... | 1996 | 8628246 |
| sequence and characterisation of a ribosomal rna operon from agrobacterium vitis. | one of the four ribosomal rna operons (rrna) from the agrobacterium vitis vitopine strain s4 was sequenced, rrna is most closely related to the rrn operons of bradyrhizobium japonicum and rhodobacter sphaeroides and carries an fmet-trna gene downstream of its 5s gene, as in the case of r. sphaeroides. the 16s rrna sequence of s4 differs from the a. vitis k309 type strain sequence by only one nucleotide, in spite of the fact that s4 and k309 have very different ti plasmids. the predicted secondar ... | 1996 | 8628253 |
| isolation of monoclonal antibodies reacting with the core component of lipopolysaccharide from rhizobium leguminosarum strain 3841 and mutant derivatives. | monoclonal antibodies reacting with the core oligosaccharide or lipid a component of rhizobium lipopolysaccharide (lps) could be useful for the elucidation of the structure and biosynthesis of this group of macromolecules. mutant derivatives of rhizobium leguminosarum 3841 with lps structures lacking the major o-antigen moiety were used as immunogens, and eight antibodies were selected for further study. all the antibodies reacted with the fast-migrating species known as lps-2 following gel elec ... | 1996 | 8631658 |
| bradyrhizobium (arachis) sp. strain nc92 contains two nodd genes involved in the repression of noda and a nola gene required for the efficient nodulation of host plants. | the common nodulation locus and closely linked nodulation genes of bradyrhizobium (arachis) sp. strain nc92 have been isolated on an 11.0-kb ecori restriction fragment. the nucleotide sequence of a 7.0-kb ecorv-ecori subclone was determined and found to contain open reading frames (orfs) homologous to the noda, nodb, nodd1, nodd2, and nola genes of bradyrhizobium japonicum and bradyrhizobium elkanii. nodulation assays of nodd1, nodd2, or nola deletion mutants on the host plants macroptilium atro ... | 1996 | 8631662 |
| a new hemoglobin gene from soybean: a role for hemoglobin in all plants. | we have isolated a new hemoglobin gene from soybean. it is expressed in cotyledons, stems of seedlings, roots, young leaves, and in some cells in the nodules that are associated with the nitrogen-fixing bradyrhizobium symbiont. this contrasts with the expression of the leghemoglobins, which are active only in the infected cells of the nodules. the deduced protein sequence of the new gene shows only 58% similarity to one of the soybean leghemoglobins, but 85-87% similarity to hemoglobins from the ... | 1996 | 8650152 |
| requirements for maturation of bradyrhizobium japonicum cytochrome c550 in escherichia coli. | various forms of bradyrhizobium japonicum cytochrome c550 (the cyca gene product) were overexpressed in escherichia coli cells grown under different conditions. antibodies directed against a synthetic cytochrome c550 peptide were used as tools to detect both, apoprotein and holoprotein. complete maturation of the apoprotein into its holo form with haem covalently bound to the polypeptide was observed only under anaerobic growth conditions and in e. coli k12 derivatives, whereas haem binding did ... | 1996 | 8654426 |
| purification and characterization of the hydrogenase from thiobacillus ferrooxidans. | hydrogenase of thiobacillus ferrooxidans atcc 19859 was purified from cells grown lithoautotrophically with 80% hydrogen, 8.6% carbon dioxide, and 11.4% air. hydrogenase was located in the 140,000 x g supernatant in cell-free extracts. the enzyme was purified 7.3-fold after chromatography on procion red and q-sepharose with a yield of 19%, resulting in a 85% pure preparation with a specific activity of 6.0 u (mg protein)-1. with native page, a mol. mass of 100 and 200 kda was determined. with sd ... | 1996 | 8661919 |
| the bradyrhizobium japonicum fixghis genes are required for the formation of the high-affinity cbb3-type cytochrome oxidase. | we report structural and functional analyses of the bradyrhizobium japonicum fixghis genes, which map immediately downstream of the fixnoqp operon for the symbiotically essential cbb3-type heme-copper oxidase complex. expression of fixghis, like that of fixnoqp, is strongly induced in cells grown microaerobically or anaerobically. a fixghi deletion led to the same prominent phenotypes as those known from a fixnoqp deletion: defective symbiotic nitrogen fixation (fix-) and decreased cytochrome ox ... | 1996 | 8661920 |
| genetic and physical mapping in brassica diploid species of a gene cluster defined in arabidopsis thaliana. | we report the genetic and physical analysis by pulse field gel electrophoresis (pfge) in three brassica diploid genomes for a cluster of five genes characterized in a selected segment of 15 kb on chromosome 3 of arabidopsis thaliana, encoding a bradyrhizobium cycj homologue (at1), a rat p67 translation factor homologue (at2), an em-like (early methionine) protein (at3), chlorophyll synthase (at4) and a yeast sac1 homologue (a5). the arabidopsis gene array was found to be conserved on a single li ... | 1996 | 8676872 |
| nitrogen fixation and nitrogen fertilization of soybeans. | abstract in pot experiments with (15)n labelled soil and mineral (15)n, the influence of bradyrhizobium (rhizobium japonicum) inoculation and n fertilization on the symbiotic n(2) fixation and yield of soybeans [glycine max (l.) merill., cv. 'fiskeby v'] was investigated. symbiotic n(2) fixation only occured after inoculation with bradyrhizobium. considerable differences in efficiency of the bacterial preparations were observed. shortly after flowering, the symbiotic nitrogen fixation was fini ... | 1996 | 22088108 |
| the rhizobium meliloti puta gene: its role in the establishment of the symbiotic interaction with alfalfa. | little is known about the energy sources used by rhizobia during colonization, invasion and root nodule formation on leguminous plants. we have recently reported that an impaired proline metabolism in rhizobium meliloti leads to a reduced nodulation efficiency and competitiveness on alfalfa roots. in the present study we have characterized the r. meliloti proline dehydrogenase gene (puta) and addressed the question of its role in symbiosis. this rhizobial gene encodes a 1224-amino-acid-long poly ... | 1997 | 9004223 |
| [a study on taxonomy of rhizobia isolated from astragalus sp]. | thirty-six strains isolated from root nodule of astragalus spp., in comparison with 31 reference strains of rhizobium, bradyrhizobium and sinorhizobium species, and some other strains isolated from legumes in xinjiang and hainian province, were classified by performing numberical taxonomy, dna-dna hybrization and partial 16s rrna gene sequencing. results of herichical analysis showed most of trains isolated from astragalus spp. fell into subgroups 8 and 9, also the dna homolgy among strains of s ... | 1997 | 11189357 |
| an important developmental role for oligosaccharides during early embryogenesis of cyprinid fish. | derivatives of chitin oligosaccharides have been shown to play a role in plant organogenesis at nanomolar concentrations. here we present data which indicate that chitin oligosaccharides are important for embryogenesis in vertebrates. we characterize chitin oligosaccharides synthesized in vitro by zebrafish and carp embryos in the late gastrulation stage by incorporation of radiolabeled n-acetyl-d-[u14c]glucosamine and by hplc in combination with enzymatic conversion using the bradyrhizobium nod ... | 1997 | 9223299 |
| comparison of partial 23s rdna sequences from rhizobium species. | a hypervariable region of rhizobium 23s rdna was amplified by polymerase chain reaction and phylogenetic relationships of several strains were determined by comparing nucleotide sequences of the amplified product. variation in the 23s rdna nucleotide sequences was consistent with phylogenetic relationships determined by host nodulation specificity and (or) 16s rdna sequence analysis. six strains representing three rhizobium species (r. leguminosarum bv. trifolii, r. meliloti, and r. etli), and t ... | 1997 | 9226872 |
| isolation and classification of a family of cyclin gene homologues in lupinus luteus. | the lupine (lupinus luteus cv. ventus) cdna clones encoding homologues of cyclin (cycb1;2, cycb1;3, cycb1;4) have been isolated from cdna library prepared from roots inoculated with bradyrhizobium lupini. comparison of the deduced amino-acid sequences of cycb1;2, cycb1;3, cycb1;4 and previously described cycb1;1 (deckert et al. 1996, biochimie 78, 90-94) showed that they share 46-65% of identical amino acids. the presence of conserved residues (renaudin et. al., in the plant cell cycle, in the p ... | 1997 | 9241352 |
| heme c incorporation into the c-type cytochromes fixo and fixp is essential for assembly of the bradyrhizobium japonicum cbb3-type oxidase. | the monoheme and diheme c-type cytochromes fixo and fixp are two of the subunits of the respiratory cbb3-type oxidase of bradyrhizobium japonicum. the cysteines of the respective heme c binding motifs cxxch were changed to serines by site-directed mutagenesis, which led to inactive oxidases in all mutants. western blot analyses showed that an intact heme binding site in the fixo polypeptide is a prerequisite not only for the synthesis of holo-fixo protein but also for the formation of the entire ... | 1997 | 9257693 |
| metals control activity and expression of the heme biosynthesis enzyme delta-aminolevulinic acid dehydratase in bradyrhizobium japonicum. | the heme biosynthesis enzyme delta-aminolevulinic acid dehydratase (alad) requires magnesium or zinc for activity, depending on the organism, and the heme moiety contains iron. thus, metals are important for heme formation in at least two different ways. bradyrhizobium japonicum alad* is an engineered derivative of wild-type alad that requires zn2+ for activity rather than mg2+ (s. chauhan and m. r. o'brian, j. biol. chem. 270:19823-19827, 1995). the ph optimum for alad* activity was over 3.5 un ... | 1997 | 9287008 |
| characterization of two plasmid-borne lps beta loci of rhizobium etli required for lipopolysaccharide synthesis and for optimal interaction with plants. | in rhizobium etli cfn42, both the symbiotic plasmid (pd) and plasmid b (pb) are required for effective bean nodulation. this is due to the presence on pb of a region (lps beta) involved in lipopolysaccharide (lps) biosynthesis. we report here the genetic array and functional features of this plasmid-borne region. the sequence analysis of a 3,595-bp fragment revealed the presence of a transcriptional unit integrated by two open reading frames (lps beta 1 and lps beta 2) essential for lps biosynth ... | 1997 | 9304861 |
| biodiversity of bradyrhizobia nodulating lupinus spp. | the genetic structure of bradyrhizobium isolates recovered from three lupinus species (lupinus campestris, lupinus montanus, and lupinus exaltatus) grown in mexico was examined. among 41 bradyrhizobium isolates, 18 electrophoretic types (ets) were distinguished by multilocus enzyme electrophoresis of five metabolic enzymes. the mean genetic diversity, 0.64, indicated that there was great genetic diversity in the population sampled. most isolates (63%) fell into two closely related clusters (clus ... | 1997 | 9336911 |
| magnetic resonance studies on the active site and metal centers of bradyrhizobium japonicum porphobilinogen synthase. | porphobilinogen synthase (pbgs) is a metalloenzyme which catalyzes the asymmetric condensation of two molecules of 5-aminolevulinic acid (ala) to form porphobilinogen. there are at least four types of pbgs, categorized according to metal ion usage. the pbgs from bradyrhizobium japonicum requires mg(ii) in catalytic metal site a, has an allosteric mg(ii) in metal site c, and also contains an activating monovalent cation binding site [petrovich et al. (1996) j. biol. chem. 271, 8692-8699]. 13c nmr ... | 1997 | 9341235 |
| genetic variation in two cultures of bradyrhizobium japonicum 110 differing in their ability to impart drought tolerance to soybean. | the polymerase chain reaction with arbitrary primers (rapd) discriminated between two separately maintained cultures of bradyrhizobium japonicum usda 110 differing in symbiotic performance under drought conditions. since strain 110 is used in inoculum production, the use of rapd to monitor inoculum cultures could help to preserve their genetic composition and prevent the loss of important symbiotic properties. the use of rapd could also be extended to other b. japonicum strains currently used in ... | 1997 | 9353221 |
| the sequences of hypf, hypc and hypd complete the hyp gene cluster required for hydrogenase activity in bradyrhizobium japonicum. | a region of dna 6 kb downstream of the hydrogenase (h2ase) structural genes and directly downstream of the hypb gene of bradyrhizobium japonicum was shown by mutational analysis to be necessary for h2ase synthesis. sequencing of this region revealed two complete open reading frames, and the 5' fragment of a third orf. they encode proteins with homologies to the hypf, hypc and the n-terminus of hypd from other h2ase-containing organisms. the hypf of b. japonicum encodes a 753-aa protein with a pr ... | 1997 | 9358044 |
| digalactosyl diacylglycerols, plant glycolipids rarely found in bacteria, are major membrane components of bacteroid forms of bradyrhizobium japonicum. | the membrane lipids of free living and bacteroid forms of bradyrhizobium japonicum, obtained from nodules occupied by both typed and untyped bacteria, were isolated and characterized by a combination of nmr spectroscopy, mass spectrometry, and other chemical and physical methods. these studies indicated that both the free living and bacteroid forms of this organism contain glycolipids almost exclusively of the type found in plant cells. in the bacteroid forms, there was a dramatic shift towards ... | 1997 | 9363436 |
| a novel transporter involved in cobalt uptake. | cobalt is an essential component of a low molecular-mass nitrile hydratase (l-nhase) from rhodococcus rhodochrous j1. we have found a new gene, nhlf, in the dna region sandwiched between nhlba encoding l-nhase and amda encoding amidase, which are involved in the degradation of nitriles. the product of nhlf, nhlf, shows a significant sequence similarity with those of hoxn from alcaligenes eutrophus, hupn from bradyrhizobium japonicum, nixa from helicobacter pylori, and ureh from bacillus sp., whi ... | 1997 | 8990157 |
| dissection of the transcription machinery for housekeeping genes of bradyrhizobium japonicum. | by using a pcr approach, the bradyrhizobium japonicum siga gene, which encodes the primary rna polymerase sigma factor, sigma80, was cloned and its nucleotide sequence was established. the deduced protein is highly homologous to the siga protein of rhizobium meliloti (72% amino acid sequence identity) but less so to rpod of escherichia coli (51% identity). well conserved is the c-terminal end of the protein, which is probably involved in promoter recognition and binding of the rna polymerase cor ... | 1997 | 8990287 |
| genetic diversity of rhizobial symbionts isolated from legume species within the genera astragalus, oxytropis, and onobrychis. | the genetic diversity of 44 rhizobial isolates from astragalus, oxytropis, and onobrychis spp. originating from different geographic locations was evaluated by mapped restriction site polymorphism (mrsp) analysis of 16s rrna genes and by pcr dna fingerprinting with repetitive sequences (rep-pcr). a comparison of tree topologies of reference strains constructed with data obtained by mrsp and by 16s rrna gene sequence analyses showed that the topologies were in good agreement, indicating that the ... | 1997 | 9406393 |
| characterization of the common bean uricase ii and its expression in organs other than nodules. | uricase ii is a purine metabolic enzyme highly induced in root nodules during the symbiosis established between legumes and bacteria of the genera rhizobium and bradyrhizobium. here we describe the characterization of bean (phaseolus vulgaris) nodule uricase ii cdna and show that uricase ii is encoded by a single gene in the bean genome. this gene is also expressed in cotyledons, roots, and hypocotyls during bean seedling establishment, and an anti-uricase antibody recognizes the protein in diff ... | 1997 | 9414545 |
| characterization of the bradyrhizobium japonicum cycy protein, a membrane-anchored periplasmic thioredoxin that may play a role as a reductant in the biogenesis of c-type cytochromes. | a new member of membrane-anchored periplasmic thioredoxin-like proteins was identified in bradyrhizobium japonicum. it is the product of cycy, the last gene in a cluster of cytochrome c biogenesis genes. mutational analysis revealed that cycy is essential for the biosynthesis of all c-type cytochromes in this bacterium. the cycy protein was shown to be exported to the periplasm by its n-terminal signal sequence-like domain. results from western blot analyses of membrane and soluble fractions ind ... | 1997 | 9020171 |
| a hydrogen-sensing system in transcriptional regulation of hydrogenase gene expression in alcaligenes species. | heterologous complementation studies using alcaligenes eutrophus h16 as a recipient identified a hydrogenase-specific regulatory dna region on megaplasmid phg21-a of the related species alcaligenes hydrogenophilus. nucleotide sequence analysis revealed four open reading frames on the subcloned dna, designated hoxa, hoxb, hoxc, and hoxj. the product of hoxa is homologous to a transcriptional activator of the family of two-component regulatory systems present in a number of h2-oxidizing bacteria. ... | 1997 | 9045826 |
| identification of the lrp gene in bradyrhizobium japonicum and its role in regulation of delta-aminolevulinic acid uptake. | the heme precursor delta-aminolevulinic acid (ala) is taken up by the dipeptide permease (dpp) system in escherichia coli. in this study, we identified a bradyrhizobium japonicum genomic library clone that complemented both ala and dipeptide uptake activities in e. coli dpp mutants. the complementing b. japonicum dna encoded a product with 58% identity to the e. coli global transcriptional regulator lrp (leucine-responsive regulatory protein), implying the presence of dpp-independent ala uptake ... | 1997 | 9045849 |
| purification and characterization of the nadp-malic enzyme from bradyrhizobium japonicum a1017. | an nadp-malic enzyme [ec 1.1.1.40] was purified to homogeneity from bradyrhizobium japonicum a1017, and the molecular and physiological characteristics were surveyed. the molecular mass of one subunit of the purified enzyme was evaluated to be 77,600 da by sds-page, and the native enzyme was a tetramer in ph 7.0 and dimer in ph 8.0 conditions, showing complex oligomeric characteristics corresponding to ph value. | 1997 | 9058984 |
| the sequence of a symbiotically essential bradyrhizobium japonicum operon consisting of trpd, trpc and a moac-like gene. | the 2767 bp bamhi-hindiii fragment specifying the trpdc genes of b. japonicum i-110 was sequenced. the trpd and trpc genes each have three highly conserved 'crawford' consensus sequences and are part of an operon with three open reading frames (orfs). the third orf has a predicted product with 58% amino-acid sequence identity with the gene product of e. coli moac, a gene encoding an enzyme involved in biosynthesis of the molybdenum cofactor required for the activity of nitrate reductase and othe ... | 1997 | 9061023 |
| hoxa is a transcriptional regulator for expression of the hup structural genes in free-living bradyrhizobium japonicum. | a chromosomally integrated bradyrhizobium japonicum hoxa mutant is unable to oxidize hydrogen in free-living conditions. derepressing conditions that induce hydrogenase activity in free-living, wild-type b. japonicum cells cannot induce expression of the hydrogenase structural genes in the hoxa mutant. the dna-binding capacity of hoxa at the hup promoter region was studied by means of gel retardation. both heterotrophically growing cells and cells induced to express hydrogenase activity contain ... | 1997 | 9076733 |
| molecular studies on a new genetic locus linked to the common nodulation genes in bradyrhizobium japonicum. | orfa, an actively transcribed genetic locus linked to the common nodulation genes in bradyrhizobium japonicum usda110, was sequenced and analysed. the expression of orfa is neither dependent on the regulatory proteins nifa, ntrc, ntrb and nodd1 nor on either copy of sigma 54, rpon1 and rpon2. the transcriptional start site of orfa was determined and found to overlap the oppositely transcribed nodz gene by 224 nucleotides. an appropriately located -10 sequence identical to the consensus proposed ... | 1997 | 9084141 |
| the dnakj operon belongs to the sigma32-dependent class of heat shock genes in bradyrhizobium japonicum. | the dnakj genes of bradyrhizobium japonicum were cloned and sequenced. they map adjacent to each other, as in other proteobacteria of the alpha and gamma subgroups. primer extension experiments identified two strongly heat-inducible transcripts starting 99 bp (t1) and 204 bp (t2) upstream of dnak. synthesis of the shorter transcript t1 in escherichia coli required the presence of a recently characterized sigma32 homologue (rpoh1) from b. japonicum. the -35 and -10 regions of the promoters associ ... | 1997 | 9108282 |
| bacterial nodulation protein nodz is a chitin oligosaccharide fucosyltransferase which can also recognize related substrates of animal origin. | the nodz gene, which is present in various soil bacteria such as bradyrhizobium japonicum, azorhizobium caulinodans, and rhizobium loti, is involved in the addition of a fucosyl residue to the reducing n-acetylglucosamine residue of lipochitin oligosaccharide (lco) signal molecules. using an escherichia coli strain that produces large quantities of the nodz protein of b. japonicum, we have purified the nodz protein to homogeneity. the purified nodz protein appears to be active in an in vitro tra ... | 1997 | 9113990 |
| replacement of pro109 by his in tlpa, a thioredoxin-like protein from bradyrhizobium japonicum, alters its redox properties but not its in vivo functions. | tlpa, the membrane-anchored, thioredoxin-like protein from bradyrhizobium japonicum, is essential for cytochrome aa3 biogenesis. the periplasmic domain of tlpa was previously shown to have protein thiol:disulfide oxidoreductase activity and reducing properties similar to those of cytoplasmic thioredoxins. here, we replaced the proline-109 in its active-site sequence c107 v108 p109 c110 by a histidine residue. the resulting active-site motif (cvhc) resembles that of oxidizing thiol:disulfide oxid ... | 1997 | 9136895 |
| nodv and nodw, a second flavonoid recognition system regulating nod gene expression in bradyrhizobium japonicum. | in bradyrhizobium japonicum, members of two global regulatory families, a lysr-type regulator, nodd1, and a two-component regulatory system, nodvw, positively regulate nod gene expression in response to plant-produced isoflavone signals. by analogy to other two-component systems, nodv and nodw are thought to activate transcription via a series of phosphorylation steps. these include the phosphorylation of nodv in response to the plant signal and the subsequent activation of nodw via the transfer ... | 1997 | 9139921 |
| three disparately regulated genes for sigma 32-like transcription factors in bradyrhizobium japonicum. | bradyrhizobium japonicum possesses a subclass of heat-shock genes whose members are transcribed from a sigma 32 consensus promoter. having identified previously one gene (rpoh1) encoding a sigma 32-like rna polymerase transcription factor, we report here the characterization of two additional rpoh-like genes (rpoh2 and rpoh3). b. japonicum thus represents the first example of an organism possessing an rpoh multigene family. all three rpoh genes encode functional proteins that are able to initiat ... | 1997 | 9140968 |
| the hypb protein from bradyrhizobium japonicum can store nickel and is required for the nickel-dependent transcriptional regulation of hydrogenase. | the hypb protein from bradyrhizobium japonicum is a metal-binding gtpase required for hydrogenase expression. in-frame mutagenesis of hypb resulted in strains that were partially or completely deficient in hydrogenase expression, depending on the degree of disruption of the gene. complete deletion of the gene yielded a strain (jh delta eg) which lacked hydrogenase activity under all conditions tested, including the situation as bacteroids from soybean nodules. mutant strain jh delta 23h lacking ... | 1997 | 9140970 |
| squalene-hopene cyclase from bradyrhizobium japonicum: cloning, expression, sequence analysis and comparison to other triterpenoid cyclases. | with the help of a pcr-based screening method, the gene encoding squalenehopene cyclase (shc) of bradyrhizobium japonicum usda 110 was isolated from a cosmid library. the shc catalyses the cyclization of squalene to hopanoids, a class of triterpenoid lipids recently discovered in nitrogen-fixing, root-nodule-forming bradyrhizobium bacteria. hybridization experiments showed that the gene is present in bacteria of all bradyrhizobium strains tested and in photosynthetic bacteria forming stem nodule ... | 1997 | 9141686 |
| roles of hoxx and hoxa in biosynthesis of hydrogenase in bradyrhizobium japonicum. | in-frame deletion mutagenesis was used to study the roles of two bradyrhizobium japonicum proteins, hoxx and hoxa, in hydrogenase biosynthesis; based on their sequences, these proteins were previously proposed to be sensor and regulator proteins, respectively, of a two-component regulatory system necessary for hydrogenase transcription. deletion of the hoxx gene resulted in a strain that expressed only 30 to 40% of wild-type hydrogenase activity. the inactive unprocessed form of the hydrogenase ... | 1997 | 9171416 |
| transcriptional regulation of delta-aminolevulinic acid dehydratase synthesis by oxygen in bradyrhizobium japonicum and evidence for developmental control of the hemb gene. | an increased demand for cytochromes is associated with symbiotic development and microaerobic metabolism in the bacterium bradyrhizobium japonicum, and evidence suggests that hemb, rather than hema, is the first essential bacterial heme synthesis gene in symbiosis with soybean. steady-state levels of mrna and protein encoded by hemb were strongly and rapidly induced by o2 deprivation as determined by rnase protection and immunoblot analyses, but hemh message was not induced. oxygen limitation re ... | 1997 | 9171420 |
| pristine environments harbor a new group of oligotrophic 2,4-dichlorophenoxyacetic acid-degrading bacteria. | 2,4-dichlorophenoxyacetic acid (2,4-d)-degrading bacteria were isolated from pristine environments which had no history of 2,4-d exposure. by using 2,4-d dye indicator medium or 14c-labeled 2,4-d medium, six strains were isolated from eight enrichment cultures capable of degrading 2,4-d. phylogenetic analyses based on 16s ribosomal dna (rdna) sequencing and physiological properties revealed that one isolate from hawaiian volcanic soil could be classified in the genus variovorax (a member of the ... | 1997 | 9172346 |
| cloning and sequence analysis of a novel insertion element from plasmids harbored by the carbofuran-degrading bacterium, sphingomonas sp. cfo6. | sphingomonas sp. cfo6 (a member of the alpha group of proteobacteria) was isolated from a washington soil by enrichment on the insecticide carbofuran as a sole source of carbon and energy. this strain has been shown to harbor five plasmids, at least some of which are required for catabolism of carbofuran. rearrangements, deletions, and loss of individual plasmids resulting in the loss of the carbofuran-degrading phenotype were observed following treatment with heat or introduction of tn5. severa ... | 1997 | 9200220 |
| genetic evidence for 5-aminoimidazole-4-carboxamide ribonucleotide (aicar) as a negative effector of cytochrome terminal oxidase cbb3 production in rhizobium etli. | a rhizobium etli tn5mob-induced mutant (cfn035) exhibits an enhanced capacity to oxidize n,n,n',n', tetramethyl-p -phenylenediamine (tmpd), a presumptive indicator of elevated cytochrome c terminal oxidase activity. sequencing of the mutated gene in cfn035 revealed that it codes for the amidophosphoribosyl transferase enzyme (purf) that catalyzes the first step in the purine biosynthetic pathway. two c-type cytochromes with molecular weights of 32 and 27 kda were produced in strain cfn035, which ... | 1997 | 9202382 |
| bradyrhizobium japonicum does not require alpha-ketoglutarate dehydrogenase for growth on succinate or malate. | the suca gene, encoding the e1 component of alpha-ketoglutarate dehydrogenase, was cloned from bradyrhizobium japonicum usda110, and its nucleotide sequence was determined. the gene shows a codon usage bias typical of non-nif and non-fix genes from this bacterium, with 89.1% of the codons being g or c in the third position. a mutant strain of b. japonicum, lsg184, was constructed with the suca gene interrupted by a kanamycin resistance marker. lsg184 is devoid of alpha-ketoglutarate dehydrogenas ... | 1997 | 8981998 |
| studies on the structure and the solution conformation of an acidic extracellular polysaccharide isolated from bradyrhizobium. | the structure of an acidic extracellular polysaccharide isolated from bradyrhizobium (chamaecytisus proliferus) has been elucidated by hydrolysis, methylation analysis, and 1d and 2d 1h- and 13c-nmr spectroscopy of the complete polysaccharide. the nmr spectrum showed that microheterogeneity was present due to the minor existence of a variety of o-acetyl groups. thus, a deacetylated sample was prepared by alkaline treatment which was then fully analysed. the deacetylated polysaccharide has the fo ... | 1997 | 9468626 |
| solution conformation and dynamics of an extracellular polysaccharide isolated from bradyrhyzobium as deduced from 1h-nmr off resonance roesy and 13c-nmr relaxation measurements. | the conformational and dynamical features of an extracellular branched deacetylated polysaccharide isolated from bradyrhizobium (chamaecytisus proliferus) have been investigated by homo and heteronuclear nmr methods. 1h-nmr cross relaxation rates have been obtained for this polysaccharide through regular noesy and roesy spectra as well as by modern off resonance roesy techniques. local proton-proton correlation times as well as interproton distances have been obtained. 13c-nmr relaxation paramet ... | 1997 | 9468627 |
| identification of the carotenoid pigment canthaxanthin from photosynthetic bradyrhizobium strains. | canthaxanthin (4,4(prm1)-diketo-(beta)-carotene) is produced as the major carotenoid pigment by orange- and dark-pink-pigmented bacteriochlorophyll-containing bradyrhizobium strains isolated from stem nodules of aeschynomene species. these two new pigmentation groups differ from the well-studied strain btai1, which accumulates spirilloxanthin as the sole carotenoid. | 1997 | 16535544 |
| characterization of bradyrhizobium strains isolated from soybean cultivation in thailand. | 1997 | 12501335 |