Publications

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
common soybean inoculant strains in brazil are members of bradyrhizobium elkanii.	the brazilian inoculant strains 29w and 587 were found to be members of bradyrhizobium elkanii primarily on the basis of 16s rrna gene sequences identical to that of b. elkanii usda76 and on the basis of reactivity with antibodies against serogroups 76 and 31, respectively. the agronomic consequences of using strains of b. elkanii as soybean inoculants are discussed.	1993	8285723
cyclic [beta]-1,6 -1,3 glucans are synthesized by bradyrhizobium japonicum bacteroids within soybean (glycine max) root nodules.	we have previously reported that free-living cultures of bradyrhizobium species produce novel oligosaccharides that are cyclic, contain between 10 and 13 glucose residues, and are linked by [beta]-1,6 and [beta]-1,3 glycosidic bonds (k.j. miller, r.s. gore, r. johnson, a.j. benesi, v.n. reinhold [1990] j bacteriol 172: 136-142). in the present study, we show that these glucans are also synthesized by bacteroids of bradyrhizobium japonicum usda 110 within glycine max root nodules.	1993	12231809
kinetics of nodule development in glycine soja.	nodule development in the interaction of glycine soja sieb. & zucc. pi468.397 with bradyrhizobium japonicum usda110 was studied by hypochlorite clearing and methylene blue staining. even the earliest stages of nodule development could be observed. the entire length of the primary root was examined up to 15 d postinoculation. markedly curled root hairs and the first cell divisions in the hypodermal layer (stage i) were observed 2 d postinoculation, and by 3 d cell division activity had spread to ...	1993	12232007
effects of ph and osmotic stress on cellular polyamine contents in the soybean rhizobia rhizobium fredii p220 and bradyrhizobium japonicum a1017.	homospermidine is a polyamine present in its highest concentrations in root nodule bacteria. by using the soybean rhizobia rhizobium fredii p220 and bradyrhizobium japonicum a1017, the effects of the ph and osmolarity of the medium on rhizobial growth and cellular polyamine contents were investigated. elevation of medium ph repressed the growth of slowly growing b. japonicum a1017 and resulted in a slight increase in cellular putrescine, while homospermidine content was not significantly affecte ...	1993	16348911
siderophore utilization by bradyrhizobium japonicum.	bradyrhizobium japonicum usda 110 and 61a152 can utilize the hydroxamate-type siderophores ferrichrome and rhodotorulate, in addition to ferric citrate, to overcome iron starvation. these strains can also utilize the pyoverdin-type siderophore pseudobactin st3. the ability to utilize another organism's siderophores may confer a selective advantage in the rhizosphere.	1993	16348945
plasmids pjp4 and r68.45 can be transferred between populations of bradyrhizobia in nonsterile soil.	incp plasmid r68.45, which carries several antibiotic resistance genes, and incp plasmid pjp4, which contains genes for mercury resistance and 2,4-dichlorophenoxyacetic acid degradation, were evaluated for their ability to transfer to soil populations of rhizobia. transfer of r68.45 was detected in nonsterile soil by using bradyrhizobium japonicum usda 123 as the plasmid donor and several bradyrhizobium sp. strains as recipients. plasmid transfer frequencies ranged up to 9.1 x 10 in soil amended ...	1993	16348953
presence of culturable bacteria in cocoons of the earthworm eisenia fetida.	viable bacteria were found to coexist with developing embryos in egg capsules (cocoons) of the earthworm eisenia fetida. earthworms were reared under standardized conditions, and bacterial densities were measured in distinct batches of cocoons collected weekly for 10 weeks. cocoons weighing 12 mg contained a mean viable bacterial population of approximately 10 cfu/g of cocoons. no difference was found in viable counts obtained from cocoons incubated at 15 degrees c and cocoons incubated at 24 de ...	1993	16348968
cloning of protocatechuate 3,4-dioxygenase genes from bradyrhizobium japonicum usda110.	a heterologous gene probe encoding the alpha and beta subunits of the pseudomonas cepacia protocatechuate 3,4-dioxygenase (pcd) was used to detect its homolog in the genome of bradyrhizobium japonicum usda110. three cosmid clones carrying a 2.2-kb bamhi insert showed high levels of pcd activity. saci digestion of one of the genomic clones, pbjg17, produced a 2.5-kb insert dna that complemented a pcd mutant of p. cepacia.	1993	16349024
genotypic diversity among strains of bradyrhizobium japonicum belonging to serogroup 110.	thirty-three strains of bradyrhizobium japonicum within serogroup 110 were examined for genotypic diversity by using dna-dna hybridization analyses. the analysis of the dna from 15 hydrogen-uptake-negative strains with the bradyrhizobial uptake hydrogenase probe phu52 showed variation in degree of homology and restriction fragment length polymorphism of ecori-restricted dna. clustering analysis of the 33 strains on the basis of dna-dna hybridization analysis with four restriction enzymes and wit ...	1993	16349053
cloning and mutagenesis of a cytochrome p-450 locus from bradyrhizobium japonicum that is expressed anaerobically and symbiotically.	cytochromes p-450, which in many organisms participate in the metabolism of a variety of endobiotic and xenobiotic substances, are synthesized by symbiotic bacteroids of bradyrhizobium japonicum. polyclonal antibodies were raised against two cytochromes p-450 (cyp112 and cyp114) purified from bacteroids. a lambda gt11 expression clone of b. japonicum usda 110 dna that reacted with the anti-cyp112 antibody was obtained and was used to screen a library of usda 110 genomic dna in plafr1 for a clone ...	1993	16349113
uptake hydrogenase (hup) in common bean (phaseolus vulgaris) symbioses.	strains of rhizobium forming nitrogen-fixing symbioses with common bean were systematically examined for the presence of the uptake hydrogenase (hup) structural genes and expression of uptake hydrogenase (hup) activity. dna with homology to the hup structural genes of bradyrhizobium japonicum was present in 100 of 248 strains examined. ecori fragments with molecular sizes of approximately 20.0 and 2.2 kb hybridized with an internal saci fragment, which contains part of both bradyrhizobial hup st ...	1993	16349115
rapid identification of rhizobia by restriction fragment length polymorphism analysis of pcr-amplified 16s rrna genes.	forty-eight strains representing the eight recognized rhizobium species, two new phaseolus bean rhizobium genomic species, bradyrhizobium spp., agrobacterium spp., and unclassified rhizobia from various host plants were examined by restriction fragment length polymorphism (rflp) analysis of 16s rrna genes amplified by polymerase chain reaction (pcr). twenty-one composite genotypes were obtained from the combined data of the rflp analysis with nine endonucleases. species assignments were in full ...	1994	16349165
a selective medium for the isolation and quantification of bradyrhizobium japonicum and bradyrhizobium elkanii strains from soils and inoculants.	the ecological examination of members of the family rhizobiaceae has been hampered by the lack of a selective medium for isolation of root nodule bacteria from soil. a novel non-antibiotic-containing medium has been developed which allows selective isolation of bradyrhizobium japonicum and b. elkanii strains from soil and inoculants. the medium, bjsm, is based on the resistance of b.japonicum and b. elkanii strains to more than 40 mug of the metals ions zn and co per ml. bjsm does not allow grow ...	1994	16349188
phylogenetic analysis of bradyrhizobium japonicum and photosynthetic stem-nodulating bacteria from aeschynomene species grown in separated geographical regions.	nearly complete and short partial 16s rrna sequences were derived from pcr-amplified ribosomal dnas of bradyrhizobium japonicum usda 136 and usda 110 and five strains of bacteriochlorophyll-synthesizing bacteria isolated from stem nodules of aeschynomene indica and other aeschynomene species growing in different geographic regions, including india, the philippines and north america. we confirmed that the five stem-nodulating strains examined synthesize bacteriochlorophyll a, and the absorption s ...	1994	16349221
variation of clonal, mesquite-associated rhizobial and bradyrhizobial populations from surface and deep soils by symbiotic gene region restriction fragment length polymorphism and plasmid profile analysis.	genetic characteristics of 14 rhizobium and 9 bradyrhizobium mesquite (prosopis glandulosa)-nodulating strains isolated from surface (0- to 0.5-m) and deep (4- to 6-m) rooting zones were determined in order to examine the hypothesis that surface- and deep-soil symbiont populations were related but had become genetically distinct during adaptation to contrasting soil conditions. to examine genetic diversity, southern blots of psti-digested genomic dna were sequentially hybridized with the noddabc ...	1994	16349226
tellurium and selenium resistance in rhizobia and its potential use for direct isolation of rhizobium meliloti from soil.	forty-eight rhizobium and bradyrhizobium strains were screened for resistance to tellurite, selenite, and selenate. high levels of resistance to the metals were observed only in rhizobium meliloti and rhizobium fredii strains; the mics were 2 to 8 mm for te(iv), >200 mm for se(vi), and 50 to 100 mm for se(iv). incorporation of se and te into growth media permitted us to directly isolate r. meliloti strains from soil. mutant strains of rhizobia having decreased levels of se and te resistance were ...	1994	16349263
genetic structure and symbiotic characteristics of a bradyrhizobium population recovered from a pasture soil.	we examined the genetic structure and symbiotic characteristics of bradyrhizobium isolates recovered from four legume species (lupinus albus [white lupine], lupinus angustifolius [blue lupine], ornithopus compressus [yellow serradella], and macroptilium atropurpureum [sirato]) grown in an oregon soil. we established that multilocus enzyme electrophoresis (mlee) can provide insights into the genetic relatedness among bradyrhizobium strains by showing a positive correlation (r = >/=0.90) between t ...	1994	16349270
increased nitrogenase-dependent h(2) photoproduction by hup mutants of rhodospirillum rubrum.	transposon tn5 mutagenesis was used to isolate mutants of rhodospirillum rubrum which lack uptake hydrogenase (hup) activity. three tn5 insertions mapped at different positions within the same 13-kb ecori fragment (fragment e1). hybridization experiments revealed homology to the structural hydrogenase genes hupslm from rhodobacter capsulatus and hupsl from bradyrhizobium japonicum in a 3.8-kb ecori-clai subfragment of fragment e1. it is suggested that this region contains at least some of the st ...	1994	16349271
factors influencing the synthesis of polysaccharide by bradyrhizobium japonicum bacteroids in field-grown soybean nodules.	certain strains of bradyrhizobium japonicum produce large quantities of polysaccharide in soybean (glycine max (l.) merr.) nodules, and nodule polysaccharide (nps) is different from that produced in culture. a previous survey of field-grown plants showed highly variable levels of nps among field sites. to obtain clues about the possible function of nps, we conducted two additional surveys of field-grown plants. the amount of polysaccharide in bulk samples of nodules was not associated with soil ...	1994	16349358
inoculation of acacia mangium with alginate beads containing selected bradyrhizobium strains under field conditions: long-term effect on plant growth and persistence of the introduced strains in soil.	the growth response of acacia mangium willd. to inoculation with selected bradyrhizobium strains was investigated in two field trials in the ivory coast (west africa). in the first trial (anguededou), four provenances (i.e., trees originating from seeds harvested in different geographical areas) of a. mangium were inoculated with four bradyrhizobium strains from different origins. six months after being transplanted in the field, the heights of all inoculated trees showed a statistically signifi ...	1994	16349430
isolation of insertion sequence isrldtal1145-1 from a rhizobium sp. (leucaena diversifolia) and distribution of homologous sequences identifying cross-inoculation group relationships.	insertion sequence (is) element isrldtal1145-1 from rhizobium sp. (leucaena diversifolia) strain tal 1145 was entrapped in the sacb gene of the positive selection vector pucd800 by insertional inactivation. a hybridization probe prepared from the whole 2.5-kb element was used to determine the distribution of homologous sequences in a diverse collection of 135 rhizobium and bradyrhizobium strains. the is probe hybridized strongly to southern blots of genomic dnas from 10 rhizobial strains that no ...	1994	16349459
precipitation of metallic cations by the acidic exopolysaccharides from bradyrhizobium japonicum and bradyrhizobium (chamaecytisus) strain bga-1.	the interaction between the acidic exopolysaccharides produced by two bradyrhizobium strains and several metal cations has been studied. aqueous solutions in the millimolar range of fe but not of fe precipitated the exopolysaccharides from bradyrhizobium (chamaecytisus) strain bga-1 and, to a lesser extent, bradyrhizobium japonicum usda 110. the precipitation was ph dependent, with a maximum around ph 3. the precipitate was redissolved by changing the ph and by fe reduction or chelation. deacety ...	1994	16349466
composition and distribution of adenylates in soybean (glycine max l.) nodule tissue.	adenylates (atp, adp, and amp) may play a central role in the regulation of the o2-limited c and n metabolism of soybean nodules. to be able to interpret measurements of adenylate levels in whole nodules and to appreciate the significance of observed changes in adenylates associated with changes in o2-limited metabolism, methods were developed for measuring in vivo levels of adenylate pools in the cortex, plant central zone, and bacteroid fractions of soybean (glycine max l. merr cv maple arrow ...	1994	12232074
cyclic [beta]-1,6-1,3-glucans of bradyrhizobium japonicum usda 110 elicit isoflavonoid production in the soybean (glycine max) host.	high levels of cyclic [beta]-1,6-1,3-glucans (e.g. 0.1 mg mg-1 of total protein) are synthesized by free-living cells as well as by bacteroids of bradyrhizobium japonicum usda 110 (k.j. miller, r.s. gore, r. johnson, a.j. benesi, v.n. reinhold [1990] j bacteriol 172: 136-142; r.s. gore and k.j. miller [1993] plant physiol 102: 191-194). these molecules share structural features with glucan fragments isolated from the mycelial cell wall of the soybean (glycine max) pathogen phytophthora megasperm ...	1994	12232136
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
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
molecular phylogenetic analysis of nitrobacter spp.	the phylogeny of bacteria belonging to the genus nitrobacter was investigated by sequencing the whole 16s rrna gene. the average level of similarity for the three nitrobacter strains examined was high (99.2%), and the similarity level between nitrobacter winogradskyi and nitrobacter sp. strain ll, which represent two different genomic species, was even higher (99.6%). when all of the nitrobacter strains and their phylogenetic neighbors bradyrhizobium and rhodopseudomonas species were considered, ...	1994	8123564
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
perception of rhizobium nodulation factors by tomato cells and inactivation by root chitinases.	the bacterial genera rhizobium and bradyrhizobium, nitrogen-fixing symbionts of legumes, secrete specific lipo-chitooligosaccharides that induce the formation of nodules on their host plants. when preparations of such nodulation-inducing factors (nod factors) were added to suspension-cultured tomato cells, a rapid and transient alkalinization of the culture medium occurred. lipo-oligosaccharide preparations from rhizobium or bradyrhizobium treated with flavonoids, known inducers of nod factor sy ...	1994	8134372
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
the nodc protein of azorhizobium caulinodans is an n-acetylglucosaminyltransferase.	nod factors are signal molecules produced by azorhizobium, bradyrhizobium, and rhizobium species that trigger nodule formation in leguminous host plants. the backbone of nod factors consists of a beta-1,4-n-acetylglucosamine oligosaccharide from which the n-acetyl group at the nonreducing end is replaced by a fatty acid. the nodabc gene products are necessary for backbone biosynthesis. by incubation of cell extracts from azorhizobium caulinodans with radioactive uridine diphosphate-n-acetylgluco ...	1994	8146173
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
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
cyclic beta-glucans of members of the family rhizobiaceae.	cyclic beta-glucans are low-molecular-weight cell surface carbohydrates that are found almost exclusively in bacteria of the rhizobiaceae family. these glucans are major cellular constituents, and under certain culture conditions their levels may reach up to 20% of the total cellular dry weight. in agrobacterium and rhizobium species, these molecules contain between 17 and 40 glucose residues linked solely by beta-(1,2) glycosidic bonds. in bradyrhizobium species, the cyclic beta-glucans are sma ...	1994	8078434
molecular genetics of the glutamine synthetases in rhizobium species.	soil bacteria of the genus rhizobium and bradyrhizobium establish symbiotic interactions with leguminous plants that result in the formation of specialized structures, the nodules, in which the bacteria differentiate into bacteroids and fix nitrogen. rhizobial glutamine synthetase (gs) activity is very low in the nodule. the ammonia produced by the bacteroids is exported to the plant cell, where it is assimilated by the gs from the plant, whereas in the free-living state, rhizobium and bradyrhiz ...	1994	7915906
dna sequence of the common nodulation genes of bradyrhizobium elkanii and their phylogenetic relationship to those of other nodulating bacteria.	a 6.6-kb bamhi fragment containing the common nodulation genes of bradyrhizobium elkanii usda94 was identified by southern hybridization using the common nod genes of b. japonicum as a probe. this fragment was cloned and sequenced. analysis of the sequence showed open reading frames highly homologous to nola, nodd2, nodd1, and nodkabc from other bradyrhizobial sources. the sequence showed higher homology to the common nod genes of bradyrhizobium sp. (parasponia) than to those from b. japonicum. ...	1994	7949325
nucleotide sequence of the rhizobium etli nods gene.	the complete nucleotide sequence of the nods gene from the bean-nodulating rhizobium etli, presumably encoding a methyltransferase, was determined. a phylogenetic analysis of five different nods proteins from three genera of gram- soil bacteria, azorhizobium, bradyrhizobium and rhizobium, was performed.	1994	7959055
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
nif gene expression in a nif+, fix- bradyrhizobium japonicum variant.	bradyrhizobium japonicum usda 110 has been shown to contain several genetically similar, naturally occurring colony morphology variants. one of these variants, l2-110, although devoid of symbiotic nitrogen fixation, retains significant levels of ex planta nitrogen fixation ability relative to other symbiotically competent usda 110 variants (mn-110 and i-110). interestingly, northern blot analyses revealed that l2-110 nodules, despite their lack of symbiotic nitrogen fixation, contained 65% the l ...	1994	7988904
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
the highly edited orf206 in oenothera mitochondria may encode a component of a heme transporter involved in cytochrome c biogenesis.	a highly transcribed region in oenothera mitochondria codes for a reading frame (orf206) which shows high homology to the marchantia encoded mitochondrial open reading frame orf277 and is also conserved in the mitochondrial genomes of arabidopsis thaliana and daucus carota. transcripts of orf206 are modified by cytidine to uridine changes in 46 positions by rna editing, affecting 30% of all cytidines and 15% of the total encoded amino acids. this orf is cotranscribed with an upstream reading fra ...	1994	8003696
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
the molecular basis of the host specificity of the rhizobium bacteria.	the interaction between soil bacteria belonging to the genera rhizobium, bradyrhizobium and azorhizobium and leguminous plants results in the induction of a new plant organ, the root nodule. after invading these root nodules via infection threads the bacteria start to fix atmospheric nitrogen into ammonia which is beneficial for the host plant. this symbiotic interaction is highly host-specific in that each rhizobial strain is able to associate with only a limited number of host plant species. t ...	1994	7718036
bradyrhizobium elkanii lipo-oligosaccharide signals induce complete nodule structures on glycine soja siebold et zucc.		1994	7764873
phosphodiesterase and phosphotriesterase in rhizobium and bradyrhizobium strains and their roles in the degradation of organophosphorus pesticides.	of 13 rhizobium and bradyrhizobium strains investigated for the production of cellular and extracellular phosphodiesterase and phosphotriesterase, all were found to produce both enzymes. phosphodiesterase was produced at a much higher level than phosphotriesterase. rhizobium meliloti tal 1373 was the most productive. the extracellular enzymes were activated by inclusion in the assay mixture of ca2+ or mg2+. the enzymes were inhibited by zn2+ but not significantly affected by cu2+, co2+ and mn2+. ...	1994	7765398
synthesis of lipooligosaccharide nodulation signals nodbj-v(rco, mefuc) and nodbj-iv(rco, mefuc) of bradyrhizobium japonicum.		1994	7841801
in situ hybridization of two nodule-specific gene products from yellow lupin.	we have applied in situ hybridization technique to examine the expression of two tissue-specific plant genes represented by cdna clones: pln-13 and pln-50 during the symbiosis of lupinus luteus with bradyrhizobium lupini. both genes are expressed in root nodules and their transcripts are restricted to the infected zone of the nodule as revealed with 35s-or 3h-labelled antisense rna probes. the number of grains over bacteroid-containing cells after hybridization with 3h-labelled probes differed d ...	1994	7843467
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
photosynthetic symbionts of aeschynomene spp. form a cluster with bradyrhizobia on the basis of fatty acid and rrna analyses.	the relationship between photosynthetic rhizobia that nodulate 10 aeschynomene species (aeschynomene afraspera, aeschynomene denticulata, aeschynomene evenia, aeschynomene indica, aeschynomene nilotica, aeschynomene pratensis, aeschynomene rudis, aeschynomene scabra, aeschynomene schimperi, and aeschynomene sensitiva) and reference strains of the genera bradyrhizobium, rhizobium, and azorhizobium was investigated by analyzing cellular fatty acid methyl esters (fame) and 16s rrna sequences. the m ...	1994	7520731
phenotypic and genotypic characterization of bradyrhizobia nodulating the leguminous tree acacia albida.	rhizobial isolates that were obtained from both surface and deep soil samples in the sahelian and sudano-guinean areas of senegal (west africa) under acacia albida trees were compared with representative strains of known rhizobial species and genera. sodium dodecyl sulfate-polyacrylamide gel electrophoresis (sds-page) of proteins was used to determine the taxonomic positions of these organisms and the relationships between isolates obtained from the surface and isolates obtained from deep soil. ...	1994	7520737
rhizobium ciceri sp. nov., consisting of strains that nodulate chickpeas (cicer arietinum l.).	the taxonomic status of 16 collection strains of chickpea (cicer arietinum l.) rhizobia which were previously determined to belong to two groups (groups a and b) were compared with reference strains belonging to different genera and species of the family rhizobiaceae. we used the following taxonomic, phylogenetic, and phenotypic characteristics and approaches to study these organisms: dna homology, guanine-plus-cytosine content, restriction fragment length polymorphism of the amplified 16s-inter ...	1994	7520739
genetic and phenetic analyses of bradyrhizobium strains nodulating peanut (arachis hypogaea l.) roots.	seventeen bradyrhizobium sp. strains and one azorhizobium strain were compared on the basis of five genetic and phenetic features: (i) partial sequence analyses of the 16s rrna gene (rdna), (ii) randomly amplified dna polymorphisms (rapd) using three oligonucleotide primers, (iii) total cellular protein profiles, (iv) utilization of 21 aliphatic and 22 aromatic substrates, and (v) intrinsic resistances to seven antibiotics. partial 16s rdna analysis revealed the presence of only two rdna homolog ...	1995	7538280
bradyrhizobium liaoningense sp. nov., isolated from the root nodules of soybeans.	seventeen strains of extra-slowly growing (esg) soybean rhizobia isolated from root nodules of glycine soja and glycine max growing in five provinces (liaoning, heilongjiang, shanxi, hubei, and anhui) in the people's republic of china were compared with 48 reference strains belonging to the genera bradyrhizobium, rhizobium, and agrobacterium by performing a numerical analysis of 191 phenotypic features. our results showed that all of the esg strains examined clustered closely in the genus bradyr ...	1995	7547289
characterization of the cmch genes of nocardia lactamdurans and streptomyces clavuligerus encoding a functional 3'-hydroxymethylcephem o-carbamoyltransferase for cephamycin biosynthesis.	sequencing of orf10 (gene cmch) of the nocardia lactamdurans cephamycin gene cluster proved that it encodes a protein with a deduced molecular mass of 57,149 da. this protein showed significant similarity to the putative o-carbamoyltransferases (o-cases) encoded by the nodu genes of rhizobium fredii and bradyrhizobium japonicum, involved in the synthesis of nodulation factors. the carbamoyl-phosphate (cp)-binding amino-acid sequence of human otcase is conserved in the cmch product. a similar cmc ...	1995	7557411
identification of rhizobium-specific intergenic mosaic elements within an essential two-component regulatory system of rhizobium species.	analysis of the dna regions upstream of the phosphoenolpyruvate carboxykinase gene (pcka) in rhizobium meliloti and rhizobium sp. strain ngr234 identified an open reading frame which was highly homologous to the agrobacterium tumefaciens chromosomal virulence gene product chvi. a second gene product, 500 bp downstream of the chvi-like gene in r. meliloti, was homologous to the a. tumefaciens chvg protein. the homology between the r. meliloti and a. tumefaciens genes was confirmed, because the r. ...	1995	7559334
ihf- and rpon-dependent regulation of hydrogenase expression in bradyrhizobium japonicum.	sequence analysis of the bradyrhizobium japonicum hydrogenase promoter regulatory region indicated the presence of a -24/-12 type promoter, which is recognized by rpon, and a potential integration host factor (ihf)-binding site. b. japonicum rpon1-/rpon2- double mutants were deficient in hydrogen-uptake activity. using plasmid-borne hup-lacz fusions, it was shown that the rpon mutants were also deficient in nickel-dependent transcriptional regulation of hydrogenase. gel-shift assays of the hydro ...	1995	7565102
cloning of nod gene regions from mesquite rhizobia and bradyrhizobia and nucleotide sequence of the nodd gene from mesquite rhizobia.	nitrogen-fixing symbiosis between bacteria and the tree legume mesquite (prosopis glandulosa) is important for the maintenance of many desert ecosystems. genes essential for nodulation and for extending the host range to mesquite were isolated from cosmid libraries of rhizobium (mesquite) sp. strain hw17b and bradyrhizobium (mesquite) sp. strain hw10h and were shown to be closely linked. all of the cosmid clones of rhizobia that extended the host range of rhizobium (parasponia) sp. strain ngr234 ...	1995	7574650
synthesis of phytohormones by plant-associated bacteria.	the plant hormones, auxins and cytokinins, are involved in several stages of plant growth and development such as cell elongation, cell division, tissue differentiation, and apical dominance. the biosynthesis and the underlying mechanism of auxins and cytokinins action are subjects of intense investigation. not only plants but also microorganisms can synthesize auxins and cytokinins. the role of phytohormone biosynthesis by microorganisms is not fully elucidated: in several cases of pathogenic f ...	1995	7576148
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
fragmentations of the large-subunit rrna in the family rhizobiaceae.	a 130-nucleotide-long rrna species corresponding to the 5' end of the 23s rrna gene was found in 96 strains belonging to different rhizobium, bradyrhizobium, and agrobacterium species. additional fragmentation in the central region of the large-subunit rrna occurred in all agrobacteria, except agrobacterium vitis, and in most rhizobium leguminosarum and rhizobium etli strains but did not occur in any of the other rhizobia and bradyrhizobia studied.	1995	7592497
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
effect of some environmental factors on rhizobium and bradyrhizobium strains.	effects of different abiotic factors (acidity, salinity, nitrate and temperature) on growth rate of root-nodule bacteria (rhizobium and bradyrhizobium) strains were investigated in vitro. strains isolated from vicia faba l., coronilla varia l. and lupinus albus l. exhibited a large variation in tolerance of the above-mentioned factors. these bacteria should be screened under stimulated conditions for enhanced survival before selection to be used for commercial inoculant production. linear correl ...	1995	7620814
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
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
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
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
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
plant isoflavonoids, pathogens and symbionts.	it has recently been discovered that when symbiotic rhizobium and bradyrhizobium cells are outside the plant they are also exposed to the isoflavonoid phytoalexins that are normally associated with pathogenic infections. how the symbionts elicit and respond to isoflavonoids may help to define the mechanisms that are used by other beneficial soil microorganisms to colonize plant roots.	1995	7728386
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