| catabolism of indole-3-acetic acid and 4- and 5-chloroindole-3-acetic acid in bradyrhizobium japonicum. | some strains of bradyrhizobium japonicum have the ability to catabolize indole-3-acetic acid. indoleacetic acid (iaa), 4-chloro-iaa (4-cl-iaa), and 5-cl-iaa were metabolized to different extents by strains 61a24 and 110. metabolites were isolated and analyzed by high-performance liquid chromatography and conventional mass spectrometry (ms) methods, including ms-mass spectroscopy, uv spectroscopy, and high-performance liquid chromatography-ms. the identified products indicate a novel metabolic pa ... | 1995 | 7592320 |
| aerobic and anaerobic regulation in rhodobacter sphaeroides 2.4.1: the role of the fnrl gene. | in rhodobacter sphaeroides 2.4.1, the cellular requirements for 5-aminolevulinic acid (ala) are in part regulated by the level of ala synthase activity, which is encoded by the hema and hemt genes. under standard growth conditions, only the hema gene is transcribed, and the level of ala synthase activity varies in response to oxygen tension. the presence of an fnr consensus sequence upstream of hema suggested that oxygen regulation of hema expression could be mediated, in part, through a homolog ... | 1995 | 7592416 |
| a bacterial thioredoxin-like protein that is exposed to the periplasm has redox properties comparable with those of cytoplasmic thioredoxins. | the membrane-anchored thioredoxin-like protein (tlpa) from the gram-negative soil bacterium bradyrhizobium japonicum was initially discovered due to its essential role in the maturation of cytochrome aa3. a soluble form of tlpa lacking the n-terminal membrane anchor acts as a protein thiol:disulfide oxidoreductase. tlpa possesses an active-site disulfide bond common to all members of the thiol:disulfide oxidoreductase family. in addition, it contains two non-active-site cysteines that form a str ... | 1995 | 7592822 |
| oxygen control of the bradyrhizobium japonicum hema gene. | the hema gene of bradyrhizobium japonicum, which encodes the first enzyme in the heme biosynthetic pathway, is regulated by oxygen. up to ninefold induction of beta-galactosidase activity is seen when cultures of b. japonicum containing either a plasmid-encoded or a chromosomally integrated hema-lacz fusion are shifted to restricted aeration. the oxygen effect is mediated via the fixlj two-component regulatory system, which regulates the expression of a number of genes involved in the nitrogen f ... | 1995 | 7608070 |
| escherichia coli genes required for cytochrome c maturation. | the so-called aeg-46.5 region of escherichia coli contains genes whose expression is induced under anaerobic growth conditions in the presence of nitrate or nitrite as the terminal electron acceptor. in this work, we have examined more closely several genes of this cluster, here designated ccmabcdefgh, that are homologous to two separate bradyrhizobium japonicum gene clusters required for the biogenesis of c-type cytochromes. a deletion mutant of e. coli which lacked all of these genes was const ... | 1995 | 7635817 |
| a mutant bradyrhizobium japonicum delta-aminolevulinic acid dehydratase with an altered metal requirement functions in situ for tetrapyrrole synthesis in soybean root nodules. | the tetrapyrrole synthesis enzyme delta-aminolevulinic acid (ala) dehydratase requires mg2+ for catalytic activity in photosynthetic organisms and in bradyrhizobium japonicum, a bacterium that can reside symbiotically within plant cells of soybean root nodules or as a free-living organism. ala dehydratase from animals and other non-photosynthetic organisms is a zn(2+)-dependent enzyme. a modified b. japonicum ala dehydratase, alad*, was constructed by site-directed mutagenesis of hemb in which t ... | 1995 | 7649992 |
| a new bradyrhizobium japonicum gene required for free-living growth and bacteroid development is conserved in other bacteria and in plants. | in the nitrogen-fixing soybean symbiont bradyrhizobium japonicum, a new dna region, orf74, was discovered which is required for optimal free-living growth and, by consequence, also necessary for the formation of an effective symbiosis. a tn5-233 insertion of orf14 resulted in a mutant, strain 74, that has a reduced growth rate in free-living cultures under all conditions tested and less than 1% residual symbiotic nitrogen fixation activity as compared with the wild type. nodule distribution and ... | 1995 | 7655065 |
| characterization of the cychjkl genes involved in cytochrome c biogenesis and symbiotic nitrogen fixation in rhizobium leguminosarum. | mutants of rhizobium leguminosarum bv. viciae unable to respire via the cytochrome aa3 pathway were identified by the inability to oxidize n,n'-dimethyl-p-phenylenediamine. two mutants which were complemented by cosmid pij1942 from an r. leguminosarum clone bank were identified. although pea nodules induced by these mutants contained many bacteroids, no symbiotic nitrogen fixation was detected. heme staining of cellular proteins revealed that all cytochrome c-type heme proteins were absent. thes ... | 1995 | 7665469 |
| a single rrna gene region in bradyrhizobium japonicum. | bradyrhizobium japonicum contains only a single rrna (rrn) gene region, despite its comparatively large genome size of 8,700 kb. the nucleotide sequence revealed an organization of rrna and trna genes that is frequently found in bacteria: 5'-rrs (16s rrna)-ilet (trna(ile))-alat (trna(ala))-rrl (23s rrna)-rrf (5s rrna)-3'. the 5' end of the primary transcript, one of the 16s rrna processing sites, and the 5' end of the mature 16s rrna were determined by primer extension. dna hybridization experim ... | 1995 | 7665496 |
| 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 ... | 1993 | 7682191 |
| synthetic studies on the lipooligosaccharide nod bj-iv (c18:1, fuc, gro) produced by bradyrhizobium japonicum strain usda61. | | 1995 | 7697654 |
| 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 |
| bradyrhizobium japonicum cytochrome c550 is required for nitrate respiration but not for symbiotic nitrogen fixation. | bradyrhizobium japonicum possesses three soluble c-type cytochromes, c550, c552, and c555. the genes for cytochromes c552 (cycb) and c555 (cycc) were characterized previously. here we report the cloning, sequencing, and mutational analysis of the cytochrome c550 gene (cyca). a b. japonicum mutant with an insertion in cyca failed to synthesize a 12-kda c-type cytochrome. this protein was detectable in the cyca mutant complemented with cloned cyca, which proves that it is the cyca gene product. th ... | 1995 | 7721713 |
| correlation of carbon monoxide association rates and the position of absorption band iii in hemoproteins. | we have examined the absorbance of a charge-transfer transition near 760 nm, known as band iii, in several hemoproteins and heme complexes. the band iii position correlates with the rate of carbon monoxide binding to the heme. a band iii present at 760 nm indicates an unfavorable geometry of the heme for carbon monoxide binding; a red-shift of the band iii to 765 nm indicates a less-constrained geometry of the heme as evidenced by higher carbon monoxide association rates. the band iii position c ... | 1995 | 7737161 |
| bradyrhizobium japonicum nodulation genetics. | studies of the genetics of nodulation by bradyrhizobium japonicum have revealed many similar features with rhizobium and azorhizobium species, but also apparent differences. the regulation of nod gene expression in b. japonicum is complex, involving the interplay of the positive regulator, nodd1, as well as a repressor, no1a. a unique feature of b. japonicum is the involvement of a two-component regulatory system, nodv and nodw, in the control of nod gene expression. it is not clear why b. japon ... | 1995 | 7737469 |
| 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 |
| rhizobial lipo-oligosaccharide nodulation factors: multidimensional chromatographic analysis of symbiotic signals involved in the development of legume root nodules. | nod factors are a group of biologically active oligosaccharide signals that are secreted by symbiotically competent bacteria of the family rhizobiaceae. their biosynthesis is determined by rhizobial nodulation (nod) genes, and is specifically induced in response to flavonoids secreted from the roots of host leguminous plants. the biological activity of nod factors on these host legumes dramatically mimics the early developmental symptoms of the rhizobium-legume symbiosis including, amongst other ... | 1995 | 7780198 |
| the structure of a novel polysaccharide produced by bradyrhizobium species within soybean nodules. | certain strains of bradyrhizobium japonicum and b. elkanii produce a polysaccharide within the root nodules of their legume host, soybean. these nodule polysaccharides (npss) were isolated and characterized. the nps produced by b. elkanii strains proved to be identical in glycosyl composition and linkages to the extracellular polysaccharide (eps) of this species indicating that the nps and eps for b. elkanii have identical structures (w.f. dudman, carbohydr. res., 66 (1978) 9-23), [formula: see ... | 1995 | 7780995 |
| synthesis of lipooligosaccharide nodulation signals nodbj-v(rco, mefuc) and nodbj-iv(rco, mefuc) of bradyrhizobium japonicum. | | 1994 | 7841801 |
| characteristics of rhizobium tianshanense sp. nov., a moderately and slowly growing root nodule bacterium isolated from an arid saline environment in xinjiang, people's republic of china. | we performed a numerical analysis of 148 phenotypic characteristics of 20 strains of root nodule bacteria isolated from an arid saline desert soil in the xinjiang region of northwestern people's republic of china and compared these organisms with 28 rhizobium and bradyrhizobium strains obtained from different regions of the people's republic of china and from other countries, including nine type strains of different species. all of the strains examined clustered into two groups at a similarity l ... | 1995 | 7857795 |
| genes required for cellulose synthesis in agrobacterium tumefaciens. | a region of the chromosome of agrobacterium tumefaciens 11 kb long containing two operons required for cellulose synthesis and a part of a gene homologous to the fixr gene of bradyrhizobium japonicum has been sequenced. one of the cellulose synthesis operons contained a gene (cela) homologous to the cellulose synthase (bsca) gene of acetobacter xylinum. the same operon also contained a gene (celc) homologous to endoglucanase genes from a. xylinum, cellulomonas uda, and erwinia chrysanthemi. the ... | 1995 | 7860585 |
| orf250 encodes a second subunit of an abc-type heme transporter in oenothera mitochondria. | a highly transcribed region in oenothera mitochondria codes for an open reading frame comprising 250 condons (orf250). this open reading frame shows high sequence similarity to the helc gene of rhodobacter capsulatus which encodes a subunit of a proposed abc-type heme transporter. transcripts of orf250 are edited by cytidine to uridine transitions at 29 sites, altering 10% of all encoded amino acids. genes homologous to helc have also been found in the bacteria bradyrhizobium japonicum and esche ... | 1995 | 7862087 |
| carbohydrate binding activities of bradyrhizobium japonicum: iv. effect of lactose and flavones on the expression of the lectin, bj38. | bj38 is a galactose/lactose-specific lectin (m(r) approximately 38,000) found at one pole of bradyrhizobium japonicum. it has been implicated in mediating the adhesion of the bacteria to soybean roots, leading to the establishment of a nitrogen-fixing symbiosis. when the ligand lactose is added to cultures of the bacteria for at least 1 h prior to harvesting the cells for bj38 isolation, the yield of the protein was found to be elevated in a dose-dependent fashion. half maximal stimulation was o ... | 1994 | 7873932 |
| the cconoqp gene cluster codes for a cb-type cytochrome oxidase that functions in aerobic respiration of rhodobacter capsulatus. | the genes for a new type of a haem-copper cytochrome oxidase were cloned from rhodobacter capsulatus strain 37b4, using the bradyrhizobium japonicum fixnoqp gene region as a hybridizing probe. four genes, probably organized in an operon (cconoqp), were identified; their products share extensive amino acid sequence similarity with the fixn, o, q and p proteins that have recently been shown to be the subunits of a cb-type oxidase. ccon is a b-type cytochrome, ccoo and ccop are membrane-bound mono- ... | 1994 | 7891558 |
| hypb protein of bradyrhizobium japonicum is a metal-binding gtpase capable of binding 18 divalent nickel ions per dimer. | bradyrhizobium japonicum hypb encodes a protein containing an extremely histidine-rich region (24 histidine residues within a 39-amino-acid stretch) and guanine nucleotide-binding domains. the product of the hypb gene was overexpressed in escherichia coli and purified by ni(2+)-charged metal chelate affinity chromatography (mcac) in a single step. in sds/page, hypb migrated at 38 kda--slightly larger than the calculated molecular mass (32.8 kda). purified hypb has gtpase activity with a kcat of ... | 1995 | 7892266 |
| overlapping promoters for two different rna polymerase holoenzymes control bradyrhizobium japonicum nifa expression. | the bradyrhizobium japonicum nifa protein, the central regulator for nitrogen fixation gene expression, is encoded in the fixrnifa operon. this operon is activated during free-living anaerobic growth and in the symbiotic root nodule bacteroid state. in addition, it is expressed in aerobic conditions, albeit at a low level. here, we report that this pattern of expression is due to the presence of two overlapping promoters: fixrp1, which is of the -24/-12 class recognized by the rna polymerase sig ... | 1995 | 7896698 |
| identification and characterization of a novel bradyrhizobium japonicum gene involved in host-specific nitrogen fixation. | to understand the genetic mechanism of host specificity in the interaction between rhizobia and their hosts, it is important to identify genes that influence both early and late steps in symbiotic development. this paper focuses on the little-understood genetics of host-specific nitrogen fixation. a deletion mutant of bradyrhizobium japonicum, strain nad163, was found to induce effective, nitrogen-fixing nodules on soybean and siratro plants but produced ineffective nodules on cowpea plants. add ... | 1994 | 7961425 |
| sequences and characterization of hupu and hupv genes of bradyrhizobium japonicum encoding a possible nickel-sensing complex involved in hydrogenase expression. | a 2.7-kb dna fragment of bradyrhizobium japonicum previously shown to be involved in hydrogenase expression has been sequenced. the area is located just upstream of the hupslcdf operon and was found to contain two open reading frames, designated hupu and hupv; these encode proteins of 35.4 and 51.8 kda, respectively. these proteins are homologous to rhodobacter capsulatus hupu, a possible repressor of hydrogenase expression in that organism. b. japonicum hupu is 54% identical to the n terminus o ... | 1994 | 7961478 |
| genetic regulation of nitrogen fixation in rhizobia. | this review presents a comparison between the complex genetic regulatory networks that control nitrogen fixation in three representative rhizobial species, rhizobium meliloti, bradyrhizobium japonicum, and azorhizobium caulinodans. transcription of nitrogen fixation genes (nif and fix genes) in these bacteria is induced primarily by low-oxygen conditions. low-oxygen sensing and transmission of this signal to the level of nif and fix gene expression involve at least five regulatory proteins, fixl ... | 1994 | 7968919 |
| nod factors of rhizobium are a key to the legume door. | symbiotic interactions between rhizobia and legumes are largely controlled by reciprocal signal exchange. legume roots excrete flavonoids which induce rhizobial nodulation genes to synthesize and excrete lipo-oligosaccharide nod factors. in turn, nod factors provoke deformation of the root hairs and nodule primordium formation. normally, rhizobia enter roots through infection threads in markedly curled root hairs. if nod factors are responsible for symbiosis-specific root hair deformation, they ... | 1994 | 7984092 |
| the adaptive acid tolerance response in root nodule bacteria and escherichia coli. | root nodule bacteria and escherichia coli show an adaptive acid tolerance response when grown under mildly acidic conditions. this is defined in terms of the rate of cell death upon exposure to acid shock at ph 3.0 and expressed in terms of a decimal reduction time, d. the d values varied with the strain and the ph of the culture medium. early exponential phase cells of three strains of rhizobium leguminosarum (wu95, 3001 and wsm710) had d values of 1, 6 and 5 min respectively when grown at ph 7 ... | 1994 | 8002711 |
| identification and characterization of the nolyz genes of bradyrhizobium japonicum. | characterization of an isoflavone-inducible locus closely linked to the common nod genes of bradyrhizobium japonicum usda110 led to the discovery of two open reading frames, designated noly and nolz. these open reading frames are preceded by a sequence with strong similarity to a consensus nodd-binding site (nod box). studies utilizing a nolz'-'lacz fusion indicated that inducible expression is dependent upon both nodd1 and nodw, transcriptional regulators that are required for the expression of ... | 1994 | 8012039 |
| a bradyrhizobium japonicum gene essential for nodulation competitiveness is differentially regulated from two promoters. | we report the identification and nucleotide sequence of a new symbiotic gene (nfec) from the soybean root nodule bacterium, bradyrhizobium japonicum. a tn5 insertion (nad14) in this gene did not affect nitrogen fixation but caused a significant delay in soybean nodulation. in addition, this mutant exhibited a reduction in its competitive ability to nodulate soybean when coinoculated with the wild type. sequence analysis of the mutated region revealed that the nad14 tn5 insertion mapped within an ... | 1994 | 8012043 |
| identification of a gene encoding a thioredoxin-like product necessary for cytochrome c biosynthesis and symbiotic nitrogen fixation in rhizobium leguminosarum. | a tn5-induced mutant of rhizobium leguminosarum bv. viciae could not form nitrogen-fixing nodules on pea or vetch because of a lesion in electron transport to oxygen. the mutant lacked spectroscopically detectable cytochromes c and aa3. no proteins containing c-type cytochrome could be identified in the mutant by heme staining of proteins fractionated on polyacrylamide gels, indicating that the mutant was defective in maturation of all c-type cytochromes. the tn5 mutation was determined to be lo ... | 1994 | 8021193 |
| heme-based sensors, exemplified by the kinase fixl, are a new class of heme protein with distinctive ligand binding and autoxidation. | fixl's are chimeric heme protein kinases from symbiotic nitrogen-fixing rhizobia. we have overexpressed three fixl variants in escherichia coli. bradyrhizobium japonicum fixl, a soluble dimeric protein, is the first full-length fixl to be purified. the other two proteins are soluble truncations of rhizobium meliloti fixl, which is a membrane protein. one contains both heme and kinase domains and is dimeric; the other has only the heme domain and is monomeric. we find that all the fixl's bind oxy ... | 1994 | 8025112 |
| in vivo nuclear magnetic resonance study of the osmoregulation of phosphocholine-substituted beta-1,3;1,6 cyclic glucan and its associated carbon metabolism in bradyrhizobium japonicum usda 110. | a phosphocholine-substituted beta-1,3;1,6 cyclic glucan (pccg), an unusual cyclic oligosaccharide, has been isolated from bradyrhizobium japonicum usda 110 (d. b. rolin, p. e. pfeffer, s. f. osman, b. s. swergold, f. kappler, and a. j. benesi, biochim. biophys. acta 1116:215-225, 1992). data presented here suggest that pccg synthesis is dependent on the carbon metabolism and that osmotic regulation of its biosynthesis parallels regulation of membrane-derived oligosaccharide biosynthesis observed ... | 1994 | 8031100 |
| monitoring of bacterial growth and structural analysis as probed by ft-ir spectroscopy. | fourier-transform infrared spectroscopy was used to explore structural changes in bacteria under different incubation conditions. in particular, differences between bradyrhizobium japonicum (brj) grown in liquid and on solid media were investigated, as well as the rearrangement of brj after transfer from one medium to the other. the ft-ir absorption bands located between 1200 and 900 cm-1 region, vary in spectral shape and intensity when brj were suspended in solution medium or plated on solid m ... | 1994 | 8031853 |
| organization of the hydrogenase gene cluster from bradyrhizobium japonicum: sequences and analysis of five more hydrogenase-related genes. | previously, the deletion of a 2.9-kb chromosomal ecori fragment of dna located 2.2 kb downstream from the end of the bradyrhizobium japonicum hydrogenase structural genes caused lack of normal-sized hydrogenase (hup) subunits and complete loss of hup activity. it was suggested that this region encodes one or more genes required for hup processing. sequencing of a 3322-bp xcmi fragment of dna covering this 2.9-kb ecori fragment within the hup gene cluster revealed the presence of five open readin ... | 1994 | 8045431 |
| 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 ... | 1993 | 8049344 |
| carbohydrate binding activities of bradyrhizobium japonicum. iii. lectin expression, bacterial binding, and nodulation efficiency. | in previous studies, evidence that the bradyrhizobium japonicum lectin, designated bj38, mediated the observed carbohydrate-specific binding activities of the bacteria, including the saccharide-specific adhesion to soybean root cells was presented. in the present study, it is found that both b. japonicum, as well as the purified bj38, bind predominantly to young emergent root hairs of soybean roots and, to a much lesser extent, to the root cap, mature root hairs, epicotyl or hypocotyl regions. t ... | 1994 | 8054992 |
| expression, purification and functional properties of a soluble form of bradyrhizobium japonicum tlpa, a thioredoxin-like protein. | the tlpa protein of bradyrhizobium japonicum was previously identified genetically as a membrane-anchored, periplasmic thioredoxin-like protein. here we describe the heterologous expression in escherichia coli, subsequent purification and biochemical characterization of tlpa. a soluble form of tlpa, which lacks its n-terminal membrane anchor, was overexpressed in e. coli and purified by a two-step procedure. pure tlpa was shown to be a monomer in solution and was active in reducing the disulfide ... | 1994 | 8055901 |
| bacterial genes and proteins involved in the biogenesis of c-type cytochromes and terminal oxidases. | a total of nine genes potentially concerned with the biosynthesis of c-type cytochromes have been identified recently in the bacteria bradyrhizobium japonicum and rhodobacter capsulatus, and homologous counterparts appear to be present also in escherichia coli. most of the respective gene products are membrane-bound, while others are located in the periplasmic space. as inferred from sequence analyses, several of these proteins may play roles in membrane transport or redox processes, both functi ... | 1994 | 8075119 |
| 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 ... | 1993 | 8101072 |
| 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 ... | 1993 | 8101485 |
| effect of iron availability on expression of the bradyrhizobium japonicum hema gene. | bradyrhizobium japonicum produces delta-aminolevulinic acid, the universal precursor of tetrapyrroles, in a reaction catalyzed by the product of the hema gene. expression of the b. japonicum hema gene is affected by iron availability. activity of a hema-lacz fusion is increased approximately threefold by iron, and rna analysis indicates that iron regulation is at the level of mrna accumulation. to our knowledge, this is the first example of an iron-regulated heme biosynthetic gene in prokaryotes ... | 1994 | 8113199 |
| cytochrome aa3 gene regulation in members of the family rhizobiaceae: comparison of copper and oxygen effects in bradyrhizobium japonicum and rhizobium tropici. | dithionite-reduced minus ferricyanide-oxidized difference spectra on membranes from rhizobium tropici (formerly rhizobium leguminosarum bv. phaseoli) incubated at progressively lower o2 concentrations showed only a slight concomitant decrease in a603, the alpha-peak of cytochrome aa3. in contrast to previous results on bradyrhizobium japonicum, r. tropici showed no significant o2-mediated reduction in the level of either coxa transcription or cytochrome aa3 activity (as measured by ascorbate-n,n ... | 1994 | 8117073 |
| 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 ... | 1993 | 8118058 |
| rhodobacter capsulatus contains a novel cb-type cytochrome c oxidase without a cua center. | the facultative phototrophic bacterium rhodobacter capsulatus is capable of growth in a wide range of environmental conditions using a highly branched electron-transfer chain. during respiratory growth of this organism reducing equivalents are conveyed to oxygen via two terminal oxidases, previously called "cyt b410" (cytochrome c oxidase) and "cyt b260" (quinol oxidase). the cytochrome c oxidase was purified to homogeneity from a semiaerobically grown r. capsulatus strain. the purified enzyme c ... | 1994 | 8130227 |
| novel malonamidases in bradyrhizobium japonicum. purification, characterization, and immunological comparison. | three novel malonamidases (e1a, e1b, and e2) occurring constitutively in bradyrhizobium japonicum were purified to electrophoretic homogeneity. they were found to catalyze one or more of the following three types of reactions: malonyl transfer to hydroxylamine (reaction 1), hydroxaminolysis of malonamate (reaction 2), and hydrolysis of malonamate (reaction 3). the molecular sizes of e1a, e1b, and e2 were 126, 107, and 103 kda, respectively, and they were each composed of two identical subunits. ... | 1994 | 8132523 |
| cytochrome oxidase evolved by tinkering with denitrification enzymes. | the cytochrome bc complex which is encoded by the fixnopq operon in bradyrhizobium japonicum, is the most distant member of the haem-copper cytochrome oxidase family. we have found that its major subunit, fixn, is homologous to the norb subunit of nitric oxide reductase in a purple bacterium. a second evolutionary link between cytochrome oxidases and denitrification enzymes is the presence of a similar binuclear copper site in cytochrome aa3 (the mitochondrial oxidase) and nitrous oxide reductas ... | 1994 | 8137905 |
| [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 ... | 1993 | 8153350 |
| sequence and characterization of three genes within the hydrogenase gene cluster of bradyrhizobium japonicum. | a 2.0-kb dna fragment downstream from the hydrogenase-encoding structural genes within the hydrogenase gene cluster of bradyrhizobium japonicum was sequenced. analysis of the nucleotide (nt) sequence revealed three open reading frames (orfs), designated hupc, hupd and hupf, which encode polypeptides of 28, 21 and 10.7 kda, respectively. based on analysis of the nt sequence and physiological studies, hupsl (hydrogenase structural genes) and hupcdf are organized as a single transcriptional unit. p ... | 1994 | 8163174 |
| functional analysis of the fixnoqp region of azorhizobium caulinodans. | the deduced amino acid sequences of four open reading frames identified upstream of the fixghi region in azorhizobium caulinodans are very similar to the putative terminal oxidase complex coded by the fixnoqp operons from rhizobium meliloti and bradyrhizobium japonicum. the expression of the a. caulinodans fixnoqp genes, which was maximal under microaerobiosis, was positively regulated by fixk and independent of nifa. in contrast to the fix- phenotype of b. japonicum and r. meliloti fixn mutants ... | 1994 | 8169204 |
| bacterial genes involved in incorporation of nickel into a hydrogenase enzyme. | nickel is an essential component of all h2-uptake hydrogenases. a fragment of dna that complements a h2-uptake-deficient but nickel-cured mutant strain (jhk7) of bradyrhizobium japonicum was isolated and sequenced. this 4.5-kb dna fragment contains four open reading frames designated as orf1, hupn, hupo, and hupp, which encode polypeptides with predicted masses of 17, 40, 19, and 63.5 kda, respectively. the last three open reading frames (hupnop) are most likely organized as an operon with a put ... | 1994 | 8197192 |
| genetic evidence for a fourth terminal oxidase in bradyrhizobium japonicum. | 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. several genes encoding terminal oxidases from b. japonicum have been cloned, but it is unknown what roles these individual oxidases play. in this paper, we describe the cloning and sequencing of the co ... | 1994 | 8200541 |
| 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 ... | 1993 | 8226669 |
| 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 ... | 1993 | 8230232 |
| 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 ... | 1993 | 8231805 |
| 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 ... | 1993 | 8240952 |
| 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 ... | 1993 | 8253065 |
| 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 ... | 1993 | 8262943 |
| 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 ... | 1993 | 8264528 |
| identification and cloning of a cyclic beta-(1-->3), beta-(1-->6)-d-glucan synthesis locus from bradyrhizobium japonicum. | a cosmid clone complementing a cyclic beta-(1-->2)-glucan biosynthesis (ndvb) mutant of rhizobium meliloti was isolated from a bradyrhizobium japonicum gene library. this clone specified synthesis of beta-(1-->3), beta-(1-->6)-linked glucans in r. meliloti. the complemented strain was osmotically tolerant and symbiotically competent on alfalfa. thus, beta-(1-->3), beta-(1-->6)-glucans can substitute functionally for beta-(1-->2)-glucans in r. meliloti. | 1993 | 8282182 |
| steady-state kinetics of malonyl-coa synthetase from bradyrhizobium japonicum and evidence for malonyl-amp formation in the reaction. | malonyl-coa synthetase catalyses the formation of malonyl-coa directly from malonate and coa with hydrolysis of atp into amp and pp1. the catalytic mechanism of malonyl-coa synthetase from bradyrhizobium japonicum was investigated by steady-state kinetics. initial-velocity studies and the product-inhibition studies with amp and ppi strongly suggested ordered bi uni uni bi ping pong ter ter system as the most probable steady-state kinetic mechanism of malonyl-coa synthetase. michaelis constants w ... | 1994 | 8297339 |
| nodz, a unique host-specific nodulation gene, is involved in the fucosylation of the lipooligosaccharide nodulation signal of bradyrhizobium japonicum. | the nodulation genes of rhizobia are regulated by the nodd gene product in response to host-produced flavonoids and appear to encode enzymes involved in the production of a lipo-chitose signal molecule required for infection and nodule formation. we have identified the nodz gene of bradyrhizobium japonicum, whose product is required for the addition of a 2-o-methylfucose residue to the terminal reducing n-acetylglucosamine of the nodulation signal. this substitution is essential for the biologic ... | 1994 | 8300517 |
| nucleotide sequences of two hydrogenase-related genes (hypa and hypb) from bradyrhizobium japonicum, one of which (hypb) encodes an extremely histidine-rich region and guanine nucleotide-binding domains. | sequencing of a 1359-bp (nrui-acci) dna fragment located approximately 5.2 kb downstream from the end of the hydrogenase structural genes of bradyrhizobium japonicum revealed two open reading frames designated hypa and hypb, encoding polypeptides with predicted molecular masses of 12.3 and 32.8 kda, respectively. both hypa and hypb showed strong homology with other genes in hydrogenase-containing bacteria. two 'c-x-x-c' motifs were contained in the deduced amino acid sequence of hypa, a motif th ... | 1994 | 8305450 |
| 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 ... | 1993 | 8316086 |
| 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 ... | 1993 | 8319882 |
| 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 ... | 1993 | 8335258 |
| 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 ... | 1993 | 8349712 |
| 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 ... | 1993 | 8352650 |
| 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 ... | 1993 | 8354459 |
| 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 ... | 1993 | 8355653 |
| 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 ... | 1993 | 8368826 |
| 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 ... | 1993 | 8380149 |
| 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 ... | 1993 | 8382462 |
| 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 ... | 1993 | 8386371 |
| 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 ... | 1993 | 8390818 |
| 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 ... | 1993 | 8399377 |
| 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 ... | 1993 | 8400132 |
| 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 ... | 1993 | 8412659 |
| 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 ... | 1993 | 8416905 |
| 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 ... | 1993 | 8423135 |
| 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 ... | 1993 | 8423157 |
| 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 ... | 1993 | 8427547 |
| 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 ... | 1993 | 8464870 |
| 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 ... | 1993 | 8464919 |
| 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', ... | 1993 | 8510650 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |