Publications

organometallic flavonoid derivatives as spectroscopic probes.	derivatives of naringenin have been synthesized with organometalcarbonyl reporting groups for ir spectroscopy attached at c-2, c-3', or c-6, and the products have been tested for the induction of nod gene expression using a rhizobium leguminosarum strain which contains the escherichia coli lacz (beta-galactosidase) gene fused to nodabc. derivatives with an ome substituent within the reporting group moiety showed residual gene induction activity.	1998	9934469
genes involved in the formation and assembly of rhizobial cytochromes and their role in symbiotic nitrogen fixation.	rhizobia fix nitrogen in a symbiotic association with leguminous plants and this occurs in nodules. a low-oxygen environment is needed for nitrogen fixation, which paradoxically has a requirement for rapid respiration to produce atp. these conflicting demands are met by control of oxygen flux and production of leghaemoglobin (an oxygen carrier) by the plant, coupled with the expression of a high-affinity oxidase by the nodule bacteria (bacteroids). many of the bacterial genes encoding cytochrome ...	1998	9889979
[structure-functional organization of exopolysaccharide biosynthetic genes in rhizobium leguminosarum bv. viciae vf39].		1998	9914965
nodfe-dependent fatty acids that lack an alpha-beta unsaturation are subject to differential transfer, leading to novel phospholipids.	in rhizobium leguminosarum, the nodabc and nodfel operons are involved in the production of lipo-chitin oligosaccharide signals that mediate host specificity. a nodfe-determined, highly unsaturated c18:4 fatty acid (trans-2, trans-4, trans-6, cis-11-octadecatetraenoic acid) is essential for the ability of the signals to induce nodule meristems and pre-infection thread structures on the host plant vicia sativa. of the nod genes, induction of only nodfe is sufficient to modify fatty acid biosynthe ...	1998	9425685
transfer of the symbiotic plasmid from rhizobium leguminosarum biovar trifolii to agrobacterium tumefaciens.	this study examined the symbiotic properties of agrobacterium transconjugants isolated by transferring a tn5-mob-marked derivative of the 315 kb megaplasmid prt4sa from rhizobium leguminosarum bv. trifolii 4s (wild-type strain) to agrobacterium tumefaciens a136 as the recipient. the genetic characteristics of the at4s transconjugant strains were ascertained by random amplified polymorphic dna (rapd) analyses and southern hybridization using tn5-mob and nod genes as probes. several of these at4s ...	1998	12501295
integration of the temperate phage phiu into the putative trna gene on the chromosome of its host rhizobium leguminosarum biovar trifolii.	the plasmid pci6, carrying the attp site of the temperate phage phiu, integrates into the attb site on the chromosome of rhizobium leguminosarum biovar trifolii strain 4s. the 4 kb ecori-hindiii region of pci6 involved in site-specific integration was subcloned as the attp fragment of phage phiu and sequenced. the attl fragment, one of the new dna junctions generated from the insertion of pci6 into the chromosome of the host rhizobium, was used as a hybridization probe for isolation of the attb ...	1998	12501298
induction of fungal disease resistance in vicia faba by dual inoculation with rhizobium leguminosarum and vesicular-arbuscular mycorrhizal fungi.	infection of vicia faba with bothytis fabae causes significant decreases in growth vigour, total nitrogen content, number of nodules and nutrient accumulation. na-uptake and phenolics concentration increased compared to that of noninfected plants. in contrast, dual inoculation of rhizobium and va mycorrhizae increased all above parameters suggesting a distinct improvement of the plants. the results also revealed that an inverse correlation may exist between phenolic, calcium, magnesium and zinc ...	1998	16284861
auxin transport inhibition precedes root nodule formation in white clover roots and is regulated by flavonoids and derivatives of chitin oligosaccharides.	the expression of the auxin responsive reporter construct, gh3:gusa, was examined in transgenic white clover plants to assess changes in the auxin balance during the earliest stages of root nodule formation. reporter gene expression was monitored at marked locations after the application of bacteria or signal molecules using two precise inoculation techniques: spot-inoculation and a novel method for ballistic microtargeting. changes in gh3:gusa expression were monitored after the inoculation of ...	1998	15494052
insertion sequences.	insertion sequences (iss) constitute an important component of most bacterial genomes. over 500 individual iss have been described in the literature to date, and many more are being discovered in the ongoing prokaryotic and eukaryotic genome-sequencing projects. the last 10 years have also seen some striking advances in our understanding of the transposition process itself. not least of these has been the development of various in vitro transposition systems for both prokaryotic and eukaryotic e ...	1998	9729608
analysis of stable low-molecular-weight rna profiles of members of the family rhizobiaceae.	staircase electrophoresis in polyacrylamide gels was used to analyze the stable low-molecular-weight (lmw) rna profiles of 24 type strains belonging to the family rhizobiaceae. this new electrophoretic technique results in good separation of the molecules forming the lmw rna profiles. differences in the number and distribution of the rna bands in these profiles allowed us to identify differences among the 24 strains assayed. species assignments based on lmw rnas proved to be consistent with the ...	1998	9575134
alanine, not ammonia, is excreted from n2-fixing soybean nodule bacteroids.	symbiotic nitrogen fixation, the process whereby nitrogen-fixing bacteria enter into associations with plants, provides the major source of nitrogen for the biosphere. nitrogenase, a bacterial enzyme, catalyzes the reduction of atmospheric dinitrogen to ammonium. in rhizobia-leguminous plant symbioses, the current model of nitrogen transfer from the symbiotic form of the bacteria, called a bacteroid, to the plant is that nitrogenase-generated ammonia diffuses across the bacteroid membrane and is ...	1998	9751786
antioxidant defenses in the peripheral cell layers of legume root nodules.	ascorbate peroxidase (ap) is a key enzyme that scavenges potentially harmful h2o2 and thus prevents oxidative damage in plants, especially in n2-fixing legume root nodules. the present study demonstrates that the nodule endodermis of alfalfa (medicago sativa) root nodules contains elevated levels of ap protein, as well as the corresponding mrna transcript and substrate (ascorbate). enhanced ap protein levels were also found in cells immediately peripheral to the infected region of soybean (glyci ...	1998	9449834
analysis of the dynamics of bacterial communities in the rhizosphere of the chrysanthemum via denaturing gradient gel electrophoresis and substrate utilization patterns	in order to gain a better understanding of the spatial and temporal dynamics of bacterial communities of the rhizosphere of the chrysanthemum, two complementary methods were used: a molecular bacterial community profiling method, i.e., 16s rrna gene-based pcr followed by denaturing gradient gel electrophoresis (dgge), and an agar plate method in which 11 sole-carbon-source utilization tests were used. the dgge patterns showed that the bacterial communities as determined from direct rhizosphere d ...	1998	9835588
analysis of biolog gn substrate utilization patterns by microbial communities.	biolog gn plates are increasingly used to characterize microbial communities by determining the ability of the communities to oxidize various carbon sources. studies were done to determine whether the biolog gn plate assay accurately reflects the catabolic potential of the inoculum used. to gain insight into which populations of microbial communities contribute to the biolog patterns, denaturing gradient gel electrophoresis and temperature gradient gel electrophoresis (tgge) were used to assess ...	1998	16349535
nodd binds to target dna in isologous octamer.	nodd, the major regulatory protein of nodulation, was partially purified from rhizobium leguminosarum 8401(pij1518), and its binding sequences within nodf promoter of r. l. bv. viciae were determined by dnase i footprinting. a series of techniques based on gel retardation were used to analyze the nodd-target dna interaction, showing that nodd binds to target dna in isologous octamer.	1998	18726214
fingerprinting of cyanobacteria based on pcr with primers derived from short and long tandemly repeated repetitive sequences.	the presence of repeated dna (short tandemly repeated repetitive [strr] and long tandemly repeated repetitive [ltrr]) sequences in the genome of cyanobacteria was used to generate a fingerprint method for symbiotic and free-living isolates. primers corresponding to the strr and ltrr sequences were used in the pcr, resulting in a method which generate specific fingerprints for individual isolates. the method was useful both with purified dna and with intact cyanobacterial filaments or cells as te ...	1998	16349487
the vibrio fischeri-euprymna scolopes light organ association: current ecological paradigms.		1998	16349524
lipopolysaccharide profiles from nodules as markers of bradyrhizobium strains nodulating wild legumes.	to develop the use of electrophoretic lipopolysaccharide profiles for bradyrhizobium strain identification, we studied the feasibility of using electrophoresis of whole legume nodule homogenates to obtain distinctive lipopolysaccharide profiles. the electrophoretic patterns were the same whether we used nodule extracts, bacteroids, or cultured bacteria as samples, and there was no evidence of changes in the ladder-like pattern during the nodulation process. to assess the reliability of using lip ...	1998	16349529
distribution of a population of rhizobium leguminosarum bv. trifolii among different size classes of soil aggregates.	a combination of the plant infection-soil dilution technique (most-probable-number [mpn] technique) and immunofluorescence direct count (ifdc) microscopy was used to examine the effects of three winter cover crop treatments on the distribution of a soil population of rhizobium leguminosarum bv. trifolii across different size classes of soil aggregates (<0.25, 0.25 to 0.5, 0.5 to 1.0, 1.0 to 2.0, and 2.0 to 5.0 mm). the aggregates were prepared from a willamette silt loam soil immediately after h ...	1998	16349531
effects of ionic and osmotic strength on the glucosyltransferase of rhizobium meliloti responsible for cyclic beta-(1,2)-glucan biosynthesis.	the cyclic beta-(1,2)-glucans of rhizobium meliloti and agrobacterium tumefaciens play an important role during hypoosmotic adaptation, and the synthesis of these compounds is osmoregulated. glucosyltransferase, the enzyme responsible for cyclic beta-(1,2)-glucan biosynthesis, is present constitutively, suggesting that osmotic regulation of the biosynthesis of these glucans occurs through modulation of enzyme activity. in this study, we examined regulation of cyclic glucan biosynthesis in vitro ...	1998	16349538
bacteria gone native vs. bacteria gone awry?: plasmidic transfer and bacterial evolution.		1997	9159098
chitin oligosaccharides can induce cortical cell division in roots of vicia sativa when delivered by ballistic microtargeting.	rhizobia, bacterial symbionts of leguminous plants, produce lipo-chitin oligosaccharide (lco) signal molecules that can induce nodule organogenesis in the cortex of legume roots in a host-specific way. the multi-unsaturated fatty acyl and the o-acetyl moieties of the lcos of rhizobium leguminosarum biovar viciae were shown to be essential for obtaining root nodule induction in vicia sativa plants. we have used ballistic microtargeting as a novel approach to deliver derivatives of the nodulation ...	1997	9428425
sym2 of pea is involved in a nodulation factor-perception mechanism that controls the infection process in the epidermis.	in pea (pisum sativum) up to 50 nodulation mutants are known, several of which are affected in the early steps of the symbiotic interaction with rhizobium sp. bacteria. here we describe the role of the sym2 gene in nodulation (nod) factor perception. our experiments show that the sym2a allele from the wild pea variety afghanistan confers an arrest in infection-thread growth if the rhizobium leguminosarum bv viciae strain does not produce nod factors with a nodx-mediated acetylation at their redu ...	1997	12223813
the rhizobium leguminosarum prsde genes are required for secretion of several proteins, some of which influence nodulation, symbiotic nitrogen fixation and exopolysaccharide modification.	nodo is a secreted protein from rhizobium leguminosarum bv. viciae with a role in signalling during legume nodulation. a tn5-induced mutant was identified that was defective in nodo secretion. as predicted, the secretion defect decreased pea and vetch nodulation but only when the node gene was also mutated. this confirms earlier observations that nodo plays a particularly important role in nodulation when nod factors carrying c18:1 (but not c18:4) acyl groups are the primary signalling molecules ...	1997	11902716
high affinity iron acquisition in rhizobium leguminosarum requires the cychjkl operon and the feupq gene products, which belong to the family of two-component transcriptional regulators.	the cychjkl operon of rhizobium leguminosarum has previously been shown to be involved in the maturation of cytochrome c, possibly by its involvement in the covalent attachment of haem to the apoprotein. mutations in the cychjkl genes abolish symbiotic nitrogen fixation. here, we show that cyc mutants are pleiotropically defective. they have lost a high affinity iron acquisition system due to their failure to make or to export siderophores. they also accumulate protoporphyrin ix, the immediate p ...	1997	9025286
nod factor-induced expression of leghemoglobin to study the mechanism of nh4no3 inhibition on root hair deformation.	nod factors secreted by rhizobium leguminosarum by, viciae induce root hair deformation, the formation of nodule primordia, and the expression of early nodulin genes in vicia sativa (vetch). root hair deformation is induced within 3 h in a small, susceptible zone (+/-2 mm) of the root. nh4no3, known to be a potent blocker of nodule formation, inhibits root hair deformation, initial cortical cell divisions, and infection thread formation. to test whether nh4no3 affects the formation of a componen ...	1997	9057327
cloning and characterization of four genes of rhizobium leguminosarum bv. trifolii involved in exopolysaccharide production and nodulation.	four different genes of rhizobium leguminosarum bv. trifolii strain rbl5599 involved in exopolysaccharide (eps) production were identified by complementation of tn5-induced eps-deficient mutants (exo mutants) with a cosmid bank. on one cosmid pssa was located, which was found to be almost identical to the pss4 gene from r. leguminosarum bv. viciae vf39 and highly homologous to a family of glycosyl transferases. two pssa mutants, exo2 and exo4, were characterized and found to produce 19 and 1% of ...	1997	9057334
analysis of a rhizobium leguminosarum gene encoding a protein homologous to glutathione s-transferases.	a novel rhizobium leguminosarum gene, gsta, the sequence of which indicated that it was a member of the gene family of glutathione s-transferases (gsts), was identified. the homology was greatest to the gst enzymes of higher plants. the rhizobium gsta gene was normally expressed at a very low level. the product of gsta was over-expressed and purified from escherichia coli. it was shown to bind to the affinity matrix glutathione-sepharose, but no enzymic gst activity with 1-chloro-2,4-dinitrobenz ...	1997	9084165
identification of soil bacteria expressing a symbiotic plasmid from rhizobium leguminosarum bv. trofolii.	a hundred strains of non-nodulating, gram-negative, rod-shaped bacteria were isolated from clover-ryegrass pastures on three different soil types and from a sandy loam under lupins. when crossed with escherichia coli pn200 containing the cointegrate plasmid ppn1, 11 transconjugants gained the ability to form nodules on the roots of white clover (trifolium repens cv. grasslands huia). a noda probe indicated that they had gained nodulation genes. the identities of these 11 strains and 4 others der ...	1997	9090106
bacterial nodulation protein nodz is a chitin oligosaccharide fucosyltransferase which can also recognize related substrates of animal origin.	the nodz gene, which is present in various soil bacteria such as bradyrhizobium japonicum, azorhizobium caulinodans, and rhizobium loti, is involved in the addition of a fucosyl residue to the reducing n-acetylglucosamine residue of lipochitin oligosaccharide (lco) signal molecules. using an escherichia coli strain that produces large quantities of the nodz protein of b. japonicum, we have purified the nodz protein to homogeneity. the purified nodz protein appears to be active in an in vitro tra ...	1997	9113990
development of an acute and chronic ecotoxicity assay using lux-marked rhizobium leguminosarum biovar trifolii.	a soil isolate of rhizobium leguminosarum bv. trifolii was marked with a lux cdabe gene cassette to enable the expression of bioluminescence. the suitability of the bacterium as a soil pollution biosensor was assessed using acute and chronic assays. bacterial bioluminescence responded sensitively to the metals studied. the order of sensitivity was found to be cd > ni = zn > cu for the acute test and cd > ni = zn = cu for the chronic test. the sensitive response of the biosensor highlighted its p ...	1997	9134778
identification of genes in rhizobium leguminosarum bv. trifolii whose products are homologues to a family of atp-binding proteins.	the specific interaction between rhizobia and their hosts requires many genes that influence both early and late steps in symbiosis. three new genes, designated prsd, prse (protein secretion) and orf3, were identified adjacent to the exo133 mutation in a cosmid carrying the genomic dna of rhizobium leguminosarum bv. trifolii ta1. the prsde genes share significant homology to the genes encoding abc transporter proteins prtde from erwinia chrysanthemi and aprde from pseudomonas aeruginosa which ex ...	1997	9141701
root colonization of different plants by plant-growth-promoting rhizobium leguminosarum bv. trifolii r39 studied with monospecific polyclonal antisera.	monospecific polyclonal antisera raised against rhizobium leguminosarum bv. trifolii r39, a bacterium which was isolated originally from red clover nodules, were used to study the colonization of roots of leguminous and nonleguminous plants (pisum sativum, lupinus albus, triticúm aestivum, and zea mays) after inoculation. eight weeks after inoculation of soil-grown plants, between 0.1 and 1% of the total bacterial population in the rhizospheres of all inoculated plants were identified as r. legu ...	1997	9143133
rhizobium gone native: unexpected plasmid stability of indigenous rhizobium leguminosarum.	lateral transfer of bacterial plasmids is thought to play an important role in microbial evolution and population dynamics. however, this assumption is based primarily on investigations of medically or agriculturally important bacterial species. to explore the role of lateral transfer in the evolution of bacterial systems not under intensive, human-mediated selection, we examined the association of genotypes at plasmid-encoded and chromosomal loci of native rhizobium, the nitrogen-fixing symbion ...	1997	9144264
new rhizobium leguminosarum flavonoid-induced proteins revealed by proteome analysis of differentially displayed proteins.	proteome analysis was used to establish the first two-dimensional protein map of rhizobium. r. leguminosarum bv. trifolii strain anu843 was grown in defined medium in the presence and absence of the flavonoid 7,4'-dihydroxyflavone. over 1,700 constitutive proteins were resolved, representing about 30% of the estimated genomic output. proteome analysis of flavonoid-treated cells was done to reveal differentially displayed proteins. the results showed that while the global expression pattern of pr ...	1997	9150598
ethylene provides positional information on cortical cell division but is not involved in nod factor-induced root hair tip growth in rhizobium-legume interaction.	nod factors secreted by rhizobium leguminosarum bv. viciae induce root hair deformation, involving a reinitiation of tip growth, and the formation of nodule primordia in vicia sativa (vetch). ethylene is a potent inhibitor of cortical cell division, an effect that can be counteracted by applying silver ions (ag+) or aminoethoxy-vinylglycine (avg). in contrast to the inhibitory effect on cortical cell division, ethylene promotes the formation of root hairs (which involves tip growth) in the root ...	1997	9165125
escherichia coli flavohaemoglobin (hmp) reduces cytochrome c and fe(iii)-hydroxamate k by electron transfer from nadh via fad: sensitivity of oxidoreductase activity to haem-bound dioxygen.	escherichia coli flavohaemoglobin (hmp) reduced purified mitochondrial cytochrome c aerobically in a reaction that was not substantially inhibited by superoxide dismutase, demonstrating that superoxide anion, the product of o2 reduction by hmp, did not contribute markedly to cytochrome c reduction. cytochrome c was reduced by hmp even in the presence of 0.5 mm co, when the haem b was locked in the ferrous, low-spin state, demonstrating that electron transfer to cytochrome c from nadh was via fad ...	1997	9168606
hydrogenase genes from rhizobium leguminosarum bv. viciae are controlled by the nitrogen fixation regulatory protein nifa.	rhizobium leguminosarum bv. viciae expresses an uptake hydrogenase in symbiosis with peas (pisum sativum) but, unlike all other characterized hydrogen-oxidizing bacteria, cannot express it in free-living conditions. the hydrogenase-specific transcriptional activator gene hoxa described in other species was shown to have been inactivated in r. leguminosarum by accumulation of frameshift and deletion mutations. symbiotic transcription of hydrogenase structural genes hupsl originates from a -24/-12 ...	1997	9177161
biocontrol of fusarium root rot in the common bean (phaseolus vulgaris l.) by using symbiotic glomus mosseae and rhizobium leguminosarum		1997	9178608
regulation of exopolysaccharide production in rhizobium leguminosarum biovar viciae wsm710 involves exor.	a mildly acid-sensitive mutant of rhizobium leguminosarum bv. viciae wsm710 (wr6-35) produced colonies which were more mucoid in phenotype than the wild-type. strain wr6-35 contained a single copy of tn5 and the observed mucoid phenotype, acid sensitivity and tn5-induced kanamycin resistance were 100% co-transducible using phage rl38. wr6-35 produced threefold more exopolysaccharide (eps) than the wild-type in minimal medium devoid of a nitrogen source. eps produced by the mutant and the wild-ty ...	1997	9202471
functional and regulatory analysis of the two copies of the fixnoqp operon of rhizobium leguminosarum strain vf39.	dna corresponding to two copies of the rhizobium leguminosarum bv. viciae strain vf39 fixnoqp operon coding for a putative symbiotic terminal oxidase of the heme-copper oxidase superfamily was cloned, sequenced, and genetically analyzed. the first copy is located upstream of the fixk-fixl region on plasmid prlevf39c, whereas the second copy resides on the nodulation plasmid prlevf39d. insertional mutagenesis with antibiotic resistance cassettes confirmed that both copies were functional, and tha ...	1997	9204566
rhizobium hainanense sp. nov., isolated from tropical legumes.	a fast-growing rhizobial group isolated from leguminous plants in hainan province, a tropical region of china, is proposed as a new rhizobium species on the basis of 16s rrna gene sequencing. dna-dna hybridization, and phenotypic characterization. this new species belongs to the phylogenetic branch which includes rhizobium leguminosarum. we propose the name rhizobium hainanense sp. nov. for this species. the strain ccbau 57015 (166) is the type strain; it has been deposited in the culture collec ...	1997	9226920
the general amino acid permease of rhizobium leguminosarum strain 3841 is negatively regulated by the ntr system.	cosmid-borne and chromosomal lacz fusions to aapj. aapq and aapm were used to examine the nitrogen regulation of the general amino acid permease (aap) of rhizobium leguminosarum strain 3841. transcription of the first gene of the operon (aapj), which encodes the periplasmic binding protein, was 2-4-fold higher than aapq and aapm, which encode the integral membrane proteins, under various growth conditions. this may be due to the presence of a putative stem loop in the intergenic region between a ...	1997	9228771
structure and role in symbiosis of the exob gene of rhizobium leguminosarum bv trifolii.	the rhizobium leguminosarum bv trifolii exob gene has been isolated by heterologous complementation of an exob mutant of r. meliloti. we have cloned a chromosomal dna fragment from the r. leguminosarum bv trifolii genome that contains an open reading frame of 981 bp showing 80% identity at the amino acid level to the udp-glucose 4-epimerase of r. meliloti. this enzyme produces udp-galactose, the donor of galactosyl residues for the lipid-linked oligosaccharide repeat units of various heteropolys ...	1997	9236769
regulation of the tca cycle and the general amino acid permease by overflow metabolism in rhizobium leguminosarum.	mutants of rhizobium leguminosarum were selected that were altered in the uptake activity of the general amino acid permease (aap). the main class of mutant maps to suca and sucd, which are part of a gene cluster mdh-succdab, which codes for malate dehydrogenase (mdh), succinyl-coa synthetase (succd) and components of the 2-oxoglutarate dehydrogenase complex (sucab). mutation of either succ or sucd prevents expression of 2-oxoglutarate dehydrogenase (sucab). conversely, mutation of suca or sucb ...	1997	9245810
deletion of escherichia coli groel is complemented by a rhizobium leguminosarum groel homologue at 37 degrees c but not at 43 degrees c.	bacterial cpn60 proteins (homologues to the escherichia coli groel protein) are often examined for function by testing their ability to complement a temperature sensitive mutation in the e. coli groel gene. such tests suffer from two drawbacks: the cpn600 protein may come from a strain with a lower optimum growth temperature than e. coli, and the requirements for successful complementation in e. coli are likely to be more stringent at 43 degrees c than at lower temperatures. here we describe the ...	1997	9266666
fnrn controls symbiotic nitrogen fixation and hydrogenase activities in rhizobium leguminosarum biovar viciae upm791.	rhizobium leguminosarum bv. viciae upm791 contains a second copy of the fnrn gene, which encodes a redox-sensitive transcriptional activator functionally homologous to escherichia coli fnr. this second copy (fnrn2) is located in the symbiotic plasmid, while fnrn1 is in the chromosome. isolation and sequencing of the fnrn2 gene revealed that the deduced amino acid sequence of fnrn2 is 87.5% identical to the sequence of fnrn1, including a conserved cysteine-rich motif characteristic of fnr-like pr ...	1997	9286975
a rhizobium leguminosarum biovar trifolii locus not localized on the sym plasmid hinders effective nodulation on plants of the pea cross-inoculation group.	introduction of the sym plasmid prl1ji into the cured rhizobium leguminosarum bv. trifolii strain rcr5 resulted in a strain, designated rbl5523, that was expected to nodulate plants of the pea cross-inoculation group. however, effective nodulation occurred only on vicia sativa plants, not on v. hirsuta or pisum sativum. after random tn5 mutagenesis, a derivative of rbl5523 was isolated that effectively nodulated and fixed nitrogen on p. sativum and v. hirsuta. characterization of the mutant, rbl ...	1997	9304865
sequence and phylogenetic analysis of the rhizobium leguminosarum biovar trifolii pyre gene, overproduction, purification and characterization of orotate phosphoribosyltransferase.	the pyre gene of rhizobium leguminosarum biovar trifolii (rl) was subcloned and its sequence is presented. the nucleotide sequence analysis suggests that this gene is not regulated by transcriptional attenuation as seen for the pyre and pyrb genes of escherichia coli (ec) and salmonella typhimurium. the rl pyre gene was subcloned into ec at2538 pyre60 where the rl pyre gene product, orotate phosphoribosyltransferase (oprtase), was overproduced. using ec at2538 pyre60 overproducing rl oprtase, th ...	1997	9305779
distribution of a sub-class of bacterial abc polar amino acid transporter and identification of an n-terminal region involved in solute specificity.	a new sub-class of binding protein-dependent transporter with specificity for a broad range of polar amino acids has been identified by sequence comparison, in rhizobium leguminosarum, rhodobacter capsulatus, escherichia coli and pseudomonas fluorescens. southern blotting and pcr analysis has shown that transporters from this new sub-class are widely distributed in gram-negative bacteria, including, in addition to the above, citrobacter freundii, erwinia carotovorum and rhizobium meliloti. abc t ...	1997	9315727
rhizobium gallicum sp. nov. and rhizobium giardinii sp. nov., from phaseolus vulgaris nodules.	thirty-one strains of two new genomic species (genomic species 1 and 2) of rhizobia isolated from root nodules of phaseolus vulgaris and originating from various locations in france were compared with reference strains of rhizobia by performing a numerical analysis of 64 phenotypic features. each genomic species formed a distinct phenon and was separated from the other rhizobial species. a comparison of the complete 16s rrna gene sequences of a representative of genomic species 1 (strain r602spt ...	1997	9336898
classification of austrian rhizobia and the mexican isolate fl27 obtained from phaseolus vulgaris l. as rhizobium gallicum.	the phylogenetic positions of four rhizobial strains obtained from nodules of common bean plants (phaseolus vulgaris l.) grown in an austrian soil and of the mexican bean isolate fl27 are described. analysis of the 16s rrna genes revealed sequences almost identical to that of the rhizobium gallicum type strain, r602sp, with a maximum of two nucleotide substitutions. comparison of the 16s rrna gene sequences with those from other bacteria indicated highest similarity to rhizobium sp. strain ok-50 ...	1997	9336913
bacterial flavohaemoglobins: a consensus sequence and identification of a discrete enterobacterial group and of further bacterial globins.	the amino acid sequences of haemoglobin-like proteins from the bacteria alcaligenes eutrophus, bacillus subtilis, erwinia chrysanthemi, escherichia coli, vibrio parahaemolyticus, vitreoscilla sp. and the yeast saccharomyces cerevisiae were studied. phylogenies based on distance and parsimony analysis showed that the eubacterial group can be easily distinguished from the other haemoglobin-like proteins. the construction of a consensus bacterial flavohaemoglobin based on the alignment of six bacte ...	1997	9351199
adaptation to nutrient starvation in rhizobium leguminosarum bv. phaseoli: analysis of survival, stress resistance, and changes in macromolecular synthesis during entry to and exit from stationary phase.	the nitrogen-fixing bacterium rhizobium leguminosarum bv. phaseoli often has to survive long periods of starvation in the soil, when not in a useful symbiotic relationship with leguminous plants. we report that it can survive carbon, nitrogen, and phosphorus starvation for at least 2 months with little loss of viability. upon carbon starvation, r. leguminosarum cells were found to undergo reductive cell division. during this period, they acquired the potential for long-term starvation-survival, ...	1997	9371432
transposon-like structure of a new plasmid-encoded restriction-modification system in rhizobium leguminosarum vf39sm.	total dna isolated from rhizobium leguminosarum vf39sm cells is resistant to cleavage by the restriction endonuclease psti. plasmid curing and transfer studies localized this phenotype to prlevf39b, the second smallest of six plasmids found in this bacterium. in vitro selection for vector modification was employed to isolate a presumptive methylase gene (m.rle39bi) from a plasmid gene library. total and plasmid dnas isolated from e. coli containing m.rlebi were resistant to digestion by psti. se ...	1997	9393436
genetic diversity of rhizobial symbionts isolated from legume species within the genera astragalus, oxytropis, and onobrychis.	the genetic diversity of 44 rhizobial isolates from astragalus, oxytropis, and onobrychis spp. originating from different geographic locations was evaluated by mapped restriction site polymorphism (mrsp) analysis of 16s rrna genes and by pcr dna fingerprinting with repetitive sequences (rep-pcr). a comparison of tree topologies of reference strains constructed with data obtained by mrsp and by 16s rrna gene sequence analyses showed that the topologies were in good agreement, indicating that the ...	1997	9406393
induction of microbial genes for pathogenesis and symbiosis by chemicals from root border cells.	reporter strains of soil-borne bacteria were used to test the hypothesis that chemicals released by root border cells can influence the expression of bacterial genes required for the establishment of plant-microbe associations. promoters from genes known to be activated by plant factors included vire, required for agrobacterium tumefaciens pathogenesis, and common nod genes from rhizobium leguminosarum bv viciae and rhizobium meliloti, required for nodulation of pea (pisum sativum) and alfalfa ( ...	1997	9414568
bacteriocin small of rhizobium leguminosarum belongs to the class of n-acyl-l-homoserine lactone molecules, known as autoinducers and as quorum sensing co-transcription factors.	small bacteriocin was isolated from the culture broth of the gram-negative bacterium rhizobium leguminosarum, which forms symbiotic nitrogen-fixing root nodules on a number of leguminous plants. the structure of the molecule was elucidated by spectroscopic methods and identified as n-(3r-hydroxy-7-cis-tetradecanoyl)-l-homoserine lactone. the absolute configuration of both asymmetric carbon atoms in the molecule was determined by the use of the chiral solvating agents s-(+)- and r-(-)-2,2,2-trifl ...	1996	8550454
cell-to-cell signaling in the symbiotic nitrogen-fixing bacterium rhizobium leguminosarum: autoinduction of a stationary phase and rhizosphere-expressed genes.	the sym plasmid prl1ji encodes functions for the formation of nitrogen-fixing pea root nodules by rhizobium leguminosarum. some of the nodulation genes are involved in recognition of chemical signals produced by the plant root, and others are required for production of chemical signals recognized by the plant. prl1ji also contains a regulatory gene, rhir, that is homologous to luxr, the transcriptional activator of luminescence genes in vibrio fischeri. luxr requires a signal compound, an autoin ...	1996	8550455
phylogenetic relationships among rhizobium species nodulating the common bean (phaseolus vulgaris l.).	the phylogenetic relationships among rhizobium species that nodulate phaseolus vulgaris (common bean) were determined by directly sequencing the amplified 16s ribosomal dna genes of these organisms. the bean strains formed four separate clusters. one cluster was composed of rhizobium leguminosarum bv. trifolii, r. leguminosarum bv. viciae, and r. leguminosarum bv. phaseoli. two other clusters comprised rhizobium etli and rhizobium tropici, and the fourth cluster contained a single bean-nodulatin ...	1996	8573502
characterization, distribution, and localization of isrl2, and insertion sequence element isolated from rhizobium leguminosarum bv. viciae.	an insertion sequence (is) element, isr12, from rhizobium leguminosarum bv. viciae strain msdj4184 was isolated by insertional inactivation of the sacrb gene of psup104-sac, which allows positive selection. isrl2 is 932 bp long, is flanked by 17-bp imperfect terminal inverted repeats, and generated a 3-bp target site duplication. isrl2 was found to be 63 to 77% homologous to insertion elements of the is5 group of the is4 superfamily. a probe incorporating a full-length copy of isrl2 was used to ...	1996	8593071
rhizobium nodulation protein noda is a host-specific determinant of the transfer of fatty acids in nod factor biosynthesis.	in the biosynthesis of lipochitin oligosaccharides (lcos) the rhizobium nodulation protein noda plays an essential role in the transfer of an acyl chain to the chitin oligosaccharide acceptor molecule. the presence of noda in the nodabcij operon makes genetic studies difficult to interpret. in order to be able to investigate the biological and biochemical functions of noda, we have constructed a test system in which the noda, nodb and nodc genes are separately present on different plasmids. effi ...	1996	8628246
isolation of monoclonal antibodies reacting with the core component of lipopolysaccharide from rhizobium leguminosarum strain 3841 and mutant derivatives.	monoclonal antibodies reacting with the core oligosaccharide or lipid a component of rhizobium lipopolysaccharide (lps) could be useful for the elucidation of the structure and biosynthesis of this group of macromolecules. mutant derivatives of rhizobium leguminosarum 3841 with lps structures lacking the major o-antigen moiety were used as immunogens, and eight antibodies were selected for further study. all the antibodies reacted with the fast-migrating species known as lps-2 following gel elec ...	1996	8631658
nmr investigations of the structural properties of the nodulation protein, nodf, from rhizobium leguminosarum and its homology with escherichia coli acyl carrier protein.	heteronuclear nmr methods have been used to elucidate the secondary structure and the general tertiary fold of the protein nodf from rhizobium leguminosarum. a similarity to acyl carrier proteins of the fatty acid synthase system had been suggested by the presence of a phosphopantetheine prosthetic group and a short stretch of sequence homology near the prosthetic group attachment site. nmr results suggest that the structural homology extends well beyond this region. both proteins have three wel ...	1996	8654592
modulation of development, growth dynamics, wall crystallinity, and infection sites in white clover root hairs by membrane chitolipooligosaccharides from rhizobium leguminosarum biovar trifolii.	we used bright-field, time-lapse video, cross-polarized, phase-contrast, and fluorescence microscopies to examine the influence of isolated chitolipooligosaccharides (closs) from wild-type rhizobium leguminosarum bv. trifolii on development of white clover root hairs, and the role of these bioactive glycolipids in primary host infection. clos action caused a threefold increase in the differentiation of root epidermal cells into root hairs. at maturity, root hairs were significantly longer becaus ...	1996	8655563
conservation of pcaq, a transcriptional activator of pca genes for catabolism of phenolic compounds, in agrobacterium tumefaciens and rhizobium species.	in agrobacterium tumefaciens a348, control of five genes for catabolism of the phenolic compound protocatechuate to beta-ketoadipate is exerted by the gene pcaq. the product of pcaq is a transcriptional activator which is distinct from regulators of the beta-ketoadipate pathway characterized in other bacterial groups. an investigation of whether pcaq is present and conserved in related rhizobium species employed southern hybridization and an agrobacterial pcad::lacz promoter probe plasmid. these ...	1996	8655573
a hierarchical analysis of population genetic structure in rhizobium leguminosarum bv. trifolii.	little is known about the population processes that shape the genetic diversity in natural populations of rhizobia. a sample of 912 rhizobium leguminosarum biovar trifolii isolates were collected from naturalized red clover populations (trifolium pratense) and analysed for 15 allozyme loci to determine the levels and distribution of genetic diversity. hierarchical analyses compared different sampling levels, geographical separation, and temporal separation. total genetic diversity across all iso ...	1996	8673267
cloning, nucleotide sequence, and expression of the brucella melitensis omp31 gene coding for an immunogenic major outer membrane protein.	the gene coding for the major outer membrane protein (omp) of 31 to 34 kda, now designated omp31, of brucella melitensis 16m was cloned and sequenced. a b. melitensis 16m genomic library was constructed in lambda gem-12 xhoi half-site arms, and recombinant phages expressing omp31 were identified by using the anti-omp31 monoclonal antibody (mab) a59/10f09/g10. subcloning of insert dna from a positive phage into pgem-7zf allowed the selection of a plasmid bearing a 4.4-kb ecori fragment that seeme ...	1996	8751924
respiratory control determines respiration and nitrogenase activity of rhizobium leguminosarum bacteroids.	the relationship between the o2 input rate into a suspension of rhizobium leguminosarum bacteroids, the cellular atp and adp pools, and the whole-cell nitrogenase activity during l-malate oxidation has been studied. it was observed that inhibition of nitrogenase by excess o2 coincided with an increase of the cellular atp/adp ratio. when under this condition the protonophore carbonyl cyanide m-chlorophenylhydrazone (cccp) was added, the cellular atp/adp ratio was lowered while nitrogenase regaine ...	1996	8755884
diversity of repc plasmid-replication sequences in rhizobium leguminosarum.	homologues of the plasmid replicator gene repc were detected and characterized in a sample of rhizobium leguminosarum strains. conserved pcr primers were designed from published sequences of repc; they amplified a fragment of about 750 bp from 39 out of 41 strains tested, and also from several sinorhizobium strains, including s. meliloti. restriction endonuclease digestion showed that the pcr product from individual strains, though uniform in size, was often heterogeneous in sequence. pcr produc ...	1996	8757735
a newly discovered gene, tfua, involved in the production of the ribosomally synthesized peptide antibiotic trifolitoxin.	trifolitoxin (tfx) is a gene-encoded, posttranslationally modified peptide antibiotic. previously, we have shown that tfxabcdefg from rhizobium leguminosarum bv. trifolii t24 is sufficient to confer tfx production and resistance to nonproducing strains within a distinct taxonomic group of the alpha-proteobacteria (e. w. triplett, b. t. breil, and g. a. splitter, appl. environ. microbiol. 60:4163-4166, 1994). here we describe strain tn5-2, a tn5 mutant of t24 defective in the production of tfx, w ...	1996	8763943
identification of a gene for a chemoreceptor of the methyl-accepting type in the symbiotic plasmid of rhizobium leguminosarum bv. viciae upm791.	the 4 kb dna region located immediately upstream of the rhizobium leguminosarum bv. viciae upm791 hydrogen structural genes was sequenced and found to encode a chemoreceptor of the methyl-accepting type, the first to be described in a rhizobial symbiotic plasmid. two additional open reading frames were found. their protein products showed sequence homology to dehydrogenases and isomerases involved in the metabolism of aromatic compounds. mutant analysis showed that this region is not required fo ...	1996	8765742
typing of rhizobia by pcr dna fingerprinting and pcr-restriction fragment length polymorphism analysis of chromosomal and symbiotic gene regions: application to rhizobium leguminosarum and its different biovars.	characterization of 43 strains of rhizobium leguminosarum biovars viciae, trifolii, and phaseoli was performed by two methodologies based on pcr amplification, i.e., pcr dna fingerprinting of interrepeat sequences and restriction fragment length polymorphism (rflp) analysis of pcr -amplified chromosomal and symbiotic gene regions. groupings generated by pcr dna fingerprinting with either extragenic palindromic repetitive primers or two different single random primers were correlated with similar ...	1996	8787401
rhizobium leguminosarum bv. trifolii produces lipo-chitin oligosaccharides with node-dependent highly unsaturated fatty acyl moieties. an electrospray ionization and collision-induced dissociation tandem mass spectrometric study.	the lipo-chitin oligosaccharides (lco) or nodulation factors synthesized by rhizobium leguminosarum bv. trifolii were analyzed using positive mode fast atom bombardment and positive and negative mode electrospray ionization mass spectrometry. from their mass spectrometric behavior it is clearly possible to distinguish between the [m + na]+ pseudomolecular ion of the node-independent molecule iv(c18:1,ac) and the [m + h]+ pseudomolecular ion of the node-dependent molecule iv(c20:4,ac), although t ...	1996	8798424
purification of pea nodule symbiosomes using an aqueous polymer two-phase system.	symbiosomes were obtained from mature pea (pisum sativum cv. argona) root nodules infected with rhizobium leguminosarum strain (biov. viciae 3841) and purified using an aqueous polymer two-phase system (aps). the aps consists of a mixture of polymers, usually dextran t500 and poly(ethylene glycol) 3350, prepared as aqueous solutions on a weight per weight basis, where each fraction distributes according to their surface characteristics. results of atpase activity, cytochrome c oxidase activity, ...	1996	8798895
the "missing" typical rhizobium leguminosarum o antigen is attached to a fatty acylated glycerol in r. leguminosarum bv. trifolii 4s, a strain that also lacks the usual tetrasaccharide "core" component.	rhizobium leguminosarum bv. trifolii 4s has a lipopolysaccharide o antigen that lacks galactose and many of the typical glycosyl components found in related strains. here, we show that it also lacks the typical core tetrasaccharide but synthesizes an alternative glycolipid that contains galactose and the typical o-antigen glycosyl components, suggesting that in this strain, the o antigen is transferred to an alternative lipid acceptor.	1996	8808946
fate of genetically modified rhizobium leguminosarum biovar viciae during long-term storage of commercial inoculants.	a study was carried out to assess the behaviour, in terms of strain survival and genetic stability, of genetically modified micro-organisms (gems) during their storage in commercial-type agricultural inoculants. three genetically modified rhizobium leguminosarum biovar viciae strains were constructed, using a gene cassette containing an inducible lacz gene from escherichia coli and mercury resistance determinants from transposon tn 1831. in the first case the genes have been integrated into the ...	1996	8810059
aspartate transport by the dct system in rhizobium leguminosarum negatively affects nitrogen-regulated operons.	amino acid uptake by the general amino acid permease (aap) of rhizobium leguminosarum strain 3841 was severely reduced by the presence of aspartate in the growth medium when glucose was the carbon source. the reduction in transport by the aap appeared to be caused by inhibition of uptake and not by transcriptional repression. however, as measured with lacz fusions, the ntr-regulated gene glnii was repressed by aspartate. the negative regulatory effect on both the aap and glnii was prevented by m ...	1996	8828229
the c-terminal domain of the rhizobium leguminosarum chitin synthase nodc is important for function and determines the orientation of the n-terminal region in the inner membrane.	the nodc genes from rhizobia encode an n-acetylglucosaminyl transferase (chitin synthase) involved in the formation of lipo-chito-oligosaccharide nod factors that initiate root nodule morphogenesis in legume plants. nodc proteins have two hydrophobic domains, one of about 21 residues at the n-terminus and a longer one, which could consist of two or three transmembrane spans, near the c-terminus. these two hydrophobic domains flank a large hydrophilic region that shows extensive homology with oth ...	1996	8830236
the in vitro biosynthesis of the exopolysaccharide produced by rhizobium leguminosarum bv. trifolii, strain na 30.	rhizobium leguminosarum bv. trifolii, strain na 30 nodulates both red (trifolium pratense) and white (t. repens) clover and produces an acidic exopolysaccharide (eps) containing glucose, galactose, glucuronic acid, acetate and ketalpyruvate residues in a 5:1:2:1:2 molar ratio. the in vitro synthesis of this eps as well as the characterization of five structurally related lipid linked oligosaccharides is described employing edta treated cells as enzyme preparation and 14c-labelled udp-glc, udp-gl ...	1996	8832106
the hydrogenase gene cluster of rhizobium leguminosarum bv. viciae contains an additional gene (hypx), which encodes a protein with sequence similarity to the n10-formyltetrahydrofolate-dependent enzyme family and is required for nickel-dependent hydrogenase processing and activity.	plasmid pal618 contains the genetic determinants for h2 uptake (hup) from rhizobium leguminosarum bv. viciae, including a cluster of 17 genes named hupslcdefghijk-hypabfcde. a 1.7-kb segment of insert dna located downstream of hype has now been sequenced, thus completing the sequence of the 20441-bp insert dna in plasmid pal618. an open reading frame (designated hypx) encoding a protein with a calculated m(r) of 62300 that exhibits extensive sequence similarity with hoxx from alcaligenes eutroph ...	1996	8842143
rhizobium leguminosarum bv. viciae contains a second fnr/fixk-like gene and an unusual fixl homologue.	genes of rhizobium leguminosarum bv. viciae vf39 coding for the regulatory elements nifa, fixl and fixk were isolated, sequenced and genetically analysed. the fixk-fixl region is located upstream of the fixnoqp operon on the non-nodulation plasmid prlevf39c. the deduced amino acid sequence of fixl revealed an unusual structure in that it contains a receiver module (homologous to the n-terminal domain of response regulators) fused to its transmitter domain. an oxygen-sensing haem-binding domain, ...	1996	8858582
nodz of bradyrhizobium extends the nodulation host range of rhizobium by adding a fucosyl residue to nodulation signals.	the nodulation genes of rhizobia are involved in the production of the lipo-chitin oligosaccharides (lco), which are signal molecules required for nodule formation. a mutation in nodz of bradyrhizobium japonicum results in the synthesis of nodulation signals lacking the wild-type 2-o-methylfucose residue at the reducting-terminal n-acetylglucosamine. this phenotype is correlated with a defective nodulation of siratro (macroptilium atropurpureum). here we show that transfer of nodz to rhizobium l ...	1996	8858593
classification of bacteria nodulating lathyrus japonicus and lathyrus pratensis in northern quebec as strains of rhizobium leguminosarum biovar viciae.	the diversity of two populations of rhizobia isolated from lathyrus japonicus (30 strains) and lathyrus pratensis (49 strains) growing in northern regions of quebec, canada, was determined on the basis of phenotypic characteristics, multilocus enzyme electrophoresis, dna-dna homology, and 16s ribosomal dna sequencing. according to numerical analysis of phenotypic characteristics, strains were divided into four groups. strains isolated from l. pratensis fell in groups i to iii; the latter include ...	1996	8863431
rhizobium leguminosarum as a plant growth-promoting rhizobacterium: direct growth promotion of canola and lettuce.	early seedling root growth of the nonlegumes canola (brassica campestris cv. tobin, brassica napus cv. westar) and lettuce (lactuca sativa cv. grand rapids) was significantly promoted by inoculation of seeds with certain strains of rhizobium leguminosarum, including nitrogen- and nonnitrogen-fixing derivatives under gnotobiotic conditions. the growth-promotive effect appears to be direct, with possible involvement of the plant growth regulators indole-3-acetic acid and cytokinin. auxotrophic rhi ...	1996	8868235
crystallization and preliminary diffraction studies of nodl, a rhizobial o-acetyl-transferase involved in the host-specific nodulation of legume roots.	the nodl specified o-acetyltransferase from the microbial symbiont rhizobium leguminosarum has been over-expressed in escherichia coli and purified using affinity-elution dye chromatography as the key step. the protein has been crystallized at 20 degrees c in 18% peg 600, 0.1 m tris/hcl buffer, ph 8.5, containing 1% dioxane, 0.25% octyl-beta-glucoside, and 5 mm coenzyme a using the hanging drop vapor diffusion method. ambient temperature x-ray diffraction studies reveal the space group to be hex ...	1996	8868492
analysis of the c-terminal secretion signal of the rhizobium leguminosarum nodulation protein nodo; a potential system for the secretion of heterologous proteins during nodule invasion.	we used deletions to analyze the domains required for secretion of the rhizobium leguminosarum bv. viciae nodulation protein, nodo, by the sec-independent pathway. deletion of the c-terminal 24 amino-acids (residues 261 to 284) reduced secretion by at least 95%. a monoclonal antibody that recognizes the c-terminal domain of nodo was used to identify four nested deletions that retained the c-terminal 24 residues of nodo but had lost up to 133 residues (amino acids 128 to 259); all four proteins w ...	1996	8870266
expression of cysteine protease genes in pea nodule development and senescence.	coding sequences for two cysteine proteases were amplified from cdna derived from pea nodule mrna using primers based on conserved regions of plant cysteine proteases. one of the amplified cdna sequences corresponded to a previously described cysteine protease gene, cyp15a, expressed in pea shoots in response to dehydration (j.t. jones and j.e. mullet, plant mol. biol. 28:1055-1065, 1995). inside the pea root nodule, in situ hybridization revealed that this gene is expressed strongly in the apic ...	1996	8870268
genetic and chemical characterization of a mutant that disrupts synthesis of the lipopolysaccharide core tetrasaccharide in rhizobium leguminosarum.	a 2-kb region that complements the tn5-derived lipopolysaccharide (lps) rough mutant rhizobium leguminosarum ru301 was sequenced. two open reading frames (orfs) were identified. the first orf (lpca) is homologous to a family of bacterial sugar transferases involved in lps core tetrasaccharide biosynthesis. orf2 (lpcb), in which tn5 transposed, has no significant homology to any dna in the genbank-embl databases. chemical characterization of lps produced by strain ru301 demonstrated that the 3-de ...	1996	8892852
the general l-amino acid permease of rhizobium leguminosarum is an abc uptake system that also influences efflux of solutes.	a general l-amino acid permease (aap) from the abc transporter family, encoded by four genes (aapj, q, m, p), has been cloned and characterized in rhizobium leguminosarum. it transports a wide range of l-amino acids but has a preference for those with polar side-chains. a single binding protein of broad specificity (aapj) is required for transport of all solutes. unusually for an abc transporter, aap has both high affinity for and supports high rates of solute uptake. genes for putative amino ac ...	1996	8898392
molecular and immunological characterization of the major outer membrane proteins of brucella.	the major outer membrane proteins (omps) of brucella spp. were initially identified in the early 1980s by selective extraction techniques and classified according to their apparent molecular mass as 36-38 kda omps or group 2 porin proteins and 31-34 kda and 25-27 kda omps which belong to the group 3 proteins. variation in apparent molecular mass is essentially due to association with peptidoglycan subunits of different sizes. two genes, omp2a and omp2b, which are closely linked in the brucella g ...	1996	8931319
the fructokinase from rhizobium leguminosarum biovar trifolii belongs to group i fructokinase enzymes and is encoded separately from other carbohydrate metabolism enzymes.	the rhizobium leguminosarum bv. trifolii bal fructokinase (frk) gene was isolated on a 2 center dot 4 kb bamhi fragment from the cosmid pla72 by complementation analysis of the tn5-induced frk mutant bal79, and confirmed by hybridization analysis. the nucleotide sequence of the frk gene was found to contain an open reading frame consisting of 978 bp encoding 326 amino acids, which was then compared to known fructokinase sequences. the fructokinase gene was not contained in an operon and is encod ...	1996	8932706
lipopolysaccharide biosynthesis in rhizobium leguminosarum. novel enzymes that process precursors containing 3-deoxy-d-manno-octulosonic acid.	the lipopolysaccharide of rhizobium leguminosarum differs from that of other gram-negative organisms. r. leguminosarum lipid a lacks phosphate groups, but it contains a galacturonic acid residue at the 4'-position and an aminogluconate moiety in place of the usual glucosamine 1-phosphate unit. r. leguminosarum lipid a is esterified with a peculiar long chain fatty acid, 27-hydroxyoctacosanoate, not found in enteric gram-negative bacteria, and the inner core of r. leguminosarum contains mannose a ...	1996	8943264
lipopolysaccharide core glycosylation in rhizobium leguminosarum. an unusual mannosyl transferase resembling the heptosyl transferase i of escherichia coli.	the lipopolysaccharide structure of the nitrogen-fixing bacterium rhizobium leguminosarum differs from that of escherichia coli in several ways, one of which is the sugar composition of the core. the e. coli inner core consists of 3-deoxy-d-manno-octulosonic acid (kdo) and l-glycero-d-manno-heptose (heptose), while the inner core of r. leguminosarum contains 2-keto-3-deoxy-d-manno-octulosonic acid (kdo), mannose, galactose, and galacturonic acid. the two kdo residues and their linkages appear to ...	1996	8943265
a special acyl carrier protein for transferring long hydroxylated fatty acids to lipid a in rhizobium.	lipid a, the hydrophobic anchor of lipopolysaccharides in the outer membranes of gram-negative bacteria, varies in structure among different rhizobiaceae. the rhizobium meliloti lipid a backbone, like that of escherichia coli, is a beta1'-6-linked glucosamine disaccharide that is phosphorylated at positions 1 and 4'. rhizobium leguminosarum lipid a lacks both phosphates, but contains aminogluconate in place of the proximal glucosamine 1-phosphate, and galacturonic acid instead of the 4'-phosphat ...	1996	8943266
deletion analysis of the 5' untranslated region of the rhizobium meliloti nodf gene.	efficient establishment of the symbiosis between rhizobia and their host plants requires precise regulation of bacterial nod genes. the nod gene transcripts in rhizobium meliloti have approximately 200 nucleotides of untranslated sequence 5' of the start codon (5' utr). we measured the significance of this region by constructing fusions between deletion derivatives of nodf and the reporter beta-glucuronidase (gus). flavonoid-inducible expression of the fusions in r. meliloti was evident when ext ...	1996	8969536
a novel type of dna-binding protein interacts with a conserved sequence in an early nodulin enod12 promoter.	the pea genes psenod12a and psenod12b are expressed in the root hairs shortly after infection with the nitrogen-fixing bacterium rhizobium leguminosarum bv. viciae or after application of purified nod factors. a 199 bp promoter fragment of the psenod12b gene contains sufficient information for nod factor-induced tissue-specific expression. we have isolated a vicia sativa cdna encoding a 1641 amino acid protein, enbp1, that interacts with the 199 bp enod12 promoter. two different dna-binding doma ...	1996	8980533
[the rhizobium leguminosarum bv viciae vf39 pssb gene product participates in symbiotic fixation of molecular nitrogen].		1996	8991547
the cytochrome bc1 complex but not cycm is necessary for symbiotic nitrogen fixation by rhizobium leguminosarum.	following tn5 mutagenesis of rhizobium leguminosarum biovar viciae, two mutants in one complementation group were identified as being unable to fix nitrogen in pea nodules. spectroscopic analysis revealed that the mutants had lowered levels of c-type cytochromes and cytochromes aa3, but increased levels of cytochrome d. cells of the mutants were greatly reduced in their ability to oxidize the artificial electron donor n,n,n',n'-tetramethyl-p-phenylenediamine but membranes prepared from them had ...	1996	9004501
characterization of rhizobium 'hedysari' by rflp analysis of pcr amplified rdna and by genomic pcr fingerprinting.	the taxonomic and discriminatory power of rflp analysis of pcr amplified parts of rhizobial rrn operons was compared to those of genomic pcr fingerprinting with arbitrary and repetitive primers. for this purpose, the two methods were applied for characterization of a group of bacterial isolates referred to as rhizobium 'hedysari'. as outgroups, representatives of the family rhizobiaceae, belonging to the rhizobium galegae, rhizobium meliloti, rhizobium leguminosarum and agrobacterium tumefaciens ...	1996	9072524