| fructose 1,6-bisphosphate aldolase activity of rhizobium species. | fdp aldolase was found to be present in the cell-free extracts of rhizobium leguminosarum, rhizobium phaseoli, rhizobium trifolii, rhizobium meliloti, rhizobium lupini, rhizobium japonicum and rhizobium species from arachis hypogaea and sesbania cannabina. the enzyme in 3 representative species has optimal activity at ph 8.4 in 0.2m veronal buffer. the enzyme activity was completely lost by treatment at 60 degrees c for 15 min. the km values were in the range from 2.38 to 4.55 x 10(-6)m fdp. met ... | 1975 | 283 |
| strain-specific antigens in rhizobium leguminosarum. | fifty strains of rhizobium leguminosarum, isolated from five species of host plant (pisum sativum, p. arvense, vicia sativa, v. faba, and a lathyrus sp.) were examined for the presence of strain-specific somatic antigens by immune-diffusions against 13 antisera. thirty eight strains (76 per cent) were found to belong to the same sero-group and were serologically indistinguishable from each other, but four of these strains also exhibited non-reciprocal cross reactivity with other antisera. in con ... | 1979 | 89766 |
| [symbiotic efficiency in spontaneous mutants of rhizobium legumino-sarum resistant to streptomyocin, spectinomycin, or kanamycin]. | symbiotic effectiveness of 45 mutant strains selected from four wild effective strains of rhizobium leguminosarum for resistance to streptomycin, spectinomycin or kanamycin was determined on vicia faba. loss of effectiveness occurred in twenty of these mutants; distribution of ineffective mutants was uniform among the three types of antibiotic resistant mutants but varied with the parent strain from which mutants have been derived. | 1975 | 125155 |
| a comparison of dna from free living and endosymbiotic rhizobium leguminosarum (strain pre). | 1. bacteroids of rhizobium leguminosarum (strain pre) purified from root nodules of pisum sativum (var. 'rondo') by the standard procedure of differential centrifugation contained considerable contamination of mitochondrial material. this could be removed by incubation of the bacteroid preparation with 1 m kcl/1% deoxycholate. 2. the dna content of bacteroid cells of r. leguminosarum was found to have increased about three fold in comparison with the dna content of free living r. leguminosarum b ... | 1975 | 172157 |
| on the efficiency of oxidative phosphorylation in membrane vesicles of azotobacter vinelandii and of rhizobium leguminosarum bacteroids. | | 1979 | 223842 |
| enzymes of ammonia assimilation in rhizobium leguminosarum bacteroids. | the activities of the following enzymes were studied in connection with dinitrogen fixation in pea bacteroids: glutamine synthetase(l-glutamate: ammonia ligase (adp-forming)(ec 6.3.1.2)(gs); glutamate dehydrogenase (nadp+)(l-glutamate: nadp+ oxidoreductase (deaminating)(ec 1.4.1.4)(gdh); glutamate synthase (l-glutamine: 2-exeglutarate aminotransferase (nadph-oxidizing))(ec 2.6.1.53)(gogat). gs activity was high throughout the growth of the plant and gogat activity was always low. it is unlikely ... | 1975 | 238731 |
| some aspects of fermentation of rhizobium leguminosarum with reference to economy of ingredients in the substrate. | incremental feeding of nutrients was found to be beneficial in mass cultivation of r. leguminosarum. similarly, semi-continuous fermentation of r. leguminosarum up to 4 days was also found to be useful in maintaining the viable number of cells. | 1978 | 373307 |
| expression of escherichia coli tryptophan operon in rhizobium leguminosarum. | rp4-trp hybrid plasmid containing escherichia coli whole tryptophan operon was conjugatively transferred from e. coli to rhizobium leguminosarum strains carrying mutations in different trp genes, converting their trp- phenotype to trp+. that the phenotype change of the r. leguminosarum cells was due to the presence of the e. coli tryptophan operon was verified by the isolation of rp4-trp hybrid plasmid from the r. leguminosarum conjugant cells, and by re-transfer of rp4-trp plasmid by conjugatio ... | 1979 | 375025 |
| host dependence of rp1-specified resistance to ampicillin: differential expression in escherichia coli and rhizobium leguminosarum. | rhizobium leguminosarum l4 is able to serve as a host for the plasmid rp1. properties of r. leguminosarum [rp1] plasmid carrier suggest that the expression of rp1-coded apr gene(s) is inhibited in this host, although the determinants of transfer and resistance to kanamycin and tetracycline are expressed. this system exemplifies a differential expression of plasmid genes in a new host. | 1979 | 391648 |
| development of the nitrogen-fixing and protein-synthesizing apparatus of bacteroids in pea root nodules. | some aspects of root nodule development of pisum sativum inoculated with rhizobium leguminosarum were examined. 1. nitrogenase activity (measured as acetylene reduction) appears to be preceded by leghemoglobin synthesis (measured immunologically). 2. syntheses of component i and component ii of nitrogenase are not strictly coordinated. synthesis of component i starts before component ii. 3. plant and bacteroid protein synthesis (measured by [35s]sulfate labeling) in root nodules declines rapidly ... | 1979 | 454614 |
| the involvement of the membrane potential in nitrogen fixation by bacteroids of rhizobium leguminosarum. | | 1979 | 467678 |
| [effect of indolylacetic acid on formation of bacteroid forms of rhizobium leguminosarum]. | the purpose of this work was to study the effect of indolylacetic acid (iaa) on the strains of rhizobium leguminosarum, effective and noneffective with respect to symbiotic nitrogen fixation (l4 and 245a, and 14--73, respectively). iaa at a concentration of 50 mcg/ml and higher inhibited the growth of the bacterium, temporarily delayed celular division, and induced intensive formation of elongated bacteroid-like cells, predominantly y-shaped or having a clavate shape. many bacteroid-like cells w ... | 1979 | 502911 |
| salt tolerance of rhizobium species in broth cultures. | salt tolerance of five rhizobia strains was examined in broth cultures. five levels of nacl concentration were used and the optical density was taken as a measure for the vigour of bacterial growth. rhizobium leguminosarum and r. meliloti were tolerant to high levels of salinity and growth curves in saline broth showed a similar pattern to the control level. rhizobium japonicum, cowpea rhizobium, and r. trifolii were intolerant to salt and showed a strong growth retardation with increasing salt ... | 1979 | 547498 |
| the effect of ammonium nitrate on the synthesis of nitrogenase and the concentration of leghemoglobin in pea root nodules induced by rhizobium leguminosarum. | the effects of nh4no3 on the development of root nodules of pisum sativum after infection with rhizobium leguminosarum (strain pre) and on the nitrogenase activity of the bacteroids in the nodule tissue were studied. the addition of nh4no3 decreased the nitrogenase activity measured on intact nodules. this reduction of nitrogen fixation did not result from a reduced number of bacteroids or a decreased amount of bacteroid proteins per gram of nodule. the synthesis of nitrogenase, measured as the ... | 1978 | 623788 |
| membrane energization in relation with nitrogen fixation in azotobacter vinelandii and rhizobium leguminosarum bacteroids. | nitrogen fixation in a. vinelandii and r. leguminosarum bacteroides shows identical characteristics with respect to the dependence on membrane energization, the sensitivity to uncouplers, the atp/adp-ratio, and the dependences on flavodoxinhydroquinone as electrondonor. although we have been successful in preparing inside-out vesicles which can be energized, attempts to couple these membranes to n2-ase were still unsuccessful. one of the major problems could be the failure to energize these vesi ... | 1978 | 667180 |
| involvement of the cytoplasmic membrane in nitrogen fixation by rhizobium leguminosarum bacteroids. | 1. the nitrogen-fixing efficiency of freshly prepared suspensions of rhizobium leguminosarum bacteroids from pea root nodules was considerably enhanced by addition of bovine serum albumin. evidence was found that during preparation of bacteroids the cell membrane is exposed to the uncoupling effect of free fatty acids and to plant phospholipase d activity. both effects could be counteracted by bovine serum albumin. 2. a technique was developed by which concentrations of free o2 and nitrogenase a ... | 1978 | 668685 |
| trifluralin effect on pisum--rhizobium relationship. | trifluralin inhibited root and shoot elongation of pisum sativum plant and caused isodiametric increase in cell volume of both tissues. the water content of the plant was not affected. the weedicide inhibited also growth and o2 uptake of rhizobium leguminosarum, isolated from pisum plant. reduction in the nitrogen content of pisum tissues was noticed, and this may be attributed to the inhibition of nodule formation. variations in the free and protein-amino acids were observed in the plant tissue ... | 1978 | 726711 |
| properties of plasmids constructed by the in vitro insertion of dna from rhizobium leguminosarum or proteus mirabilis into rp4. | plasmids have been constructed by insertion of dna from rhizobium leguminosarum or proteus mirabilis into rp4 (an r factor of group p). such recombinant plasmids retain the wide host range of the parental plasmid, being as efficiently transmissible as the unmodified rp4 and are stably maintained in rapidly growing cultures. the recombinant plasmids, even though each contained a dna sequence absolutely identical with that of the host strain, are no more efficient at mobilizing the transfer of chr ... | 1976 | 787766 |
| studies on phage 1p receptors in rhizobium trifolii and rhizobium leguminosarum. | the rate of phage 1p attachment to rhizobium cell walls was increased in the presence of ethylenediaminetetraacetic acid (edta). on the other hand the rate of adsorption of phage 1p to the triton -- insoluble cell walls was diminished. the subsequent treatment of cell walls with 2% triton x-100 and 5mm edta caused a more substantial decline of the phage inactivating capacity. lipopolysaccharides (lps) isolated from the sensitive strains, contrary to those from phage-resistant mutants, inactivate ... | 1975 | 813494 |
| discrimination of rhizobium japonicum, rhizobium lupini, rhizobium trifolii, rhizobium leguminosarum and of bacteroids by uptake of 2-ketoglutaric acid, glutamic acid and phosphate. | rhizobium strains (one each of rh. japonicum, rh. lupini, rh. leguminosarum) take up 2-ketoglutaric acid in general much faster and from lower concentrations in the medium than strains of escherichia coli, bacillus subtilis and chromobacterium violaceum. a strain of enterobacter aerogenes, however, is more similar to some rhizobium strains. the same strains of rhizobium take up also phosphate much faster and from lower concentrations than the other bacteria tested. 4 strains of rh. lupini proved ... | 1976 | 818969 |
| improved method for preparing anaerobic bacteroid suspensions of rhizobium leguminosarum for the acetylene reduction assay. | a method using ethylenediaminetetraacetate (edta) and toluene-treated pea bacteroid suspensions for the acetylene reduction assay is described. the high level of acetylene reduction by these bacteroids is comparable to that of intact plants. reproducibility of the edta-toluene treatment is, on the average, within 5%. preliminary experiments with soybeans indicate that the edta-toluene method might be applicable to other legumes as well. | 1976 | 820257 |
| chromosomal recombination and mapping in rhizobium leguminosarum. | | 1976 | 826827 |
| binding of pea lectins to a glycan type polysaccharide in the cell walls of rhizobium leguminosarum. | | 1977 | 838048 |
| zeatin ribonucleosides in the transfer ribonucleic acid of rhizobium leguminosarum, agrobacterium tumefaciens, corynebacterium fascians, and erwinia amylovora. | until recently, the presence in transfer ribonucleic acid (trna) of the hydroxylated cytokinin ribosylzeatin [n6-(4-hydroxy-3-methylbut-2-enyl)adenosine]was thought to be unique to higher plants. this extension of work from several laboratories indicates the presence of 2-methylthioribosylzeatin in the trna of the plant-associated bacteria rhizobium leguminosarum, agrobacterium tumefaciens, and corynebacterium fascians, but not in that of erwinia amylovora. this cytokinin has the cis configurati ... | 1977 | 893341 |
| [electrophoretic characteristics of the protein composition of mutant forms of pea nodular bacteria]. | a water-soluble protein fraction was studied by gel electrophoresis in the parent and mutant forms of the nodule bacterium rhizobium leguminosarum. the composition of this fraction changed under the action of ntg. changes in the composition of protein components in the mutants as compared with that of the parent strain are caused presumably by their modified specificity. | 1977 | 909477 |
| mixed inoculations with effective and ineffective strains of rhizobium leguminosarum. | | 1976 | 939736 |
| identification of the rhizobium strains in pea root nodules using genetic markers. | pea plants were inoculated jointly with pairs of genetically marked strains of rhizobium leguminosarum. out of 297 modules examined 56 contained both inoculant strains. the ratios of the strains in the inoculum did not affect the frequencies of mixed nodules. generally one of the strains consistently occupied the majority of the nodules and ithe mixed nodules comprised the majority of bacteria. transfer of the p-group r factor, rp4, between certain strains of rhizobium within mixed nodules was d ... | 1975 | 1141859 |
| insecticides and soil microorganisms. iii. fate of 14c-labelled dipterex as affected by two nodule-forming rhizobium spp. and roots of their respective leguminous host plants. | chromatographic analysis led to the identification of monomethyl- and dimethyl-phosphates as metabolites resulting from the enzymatic degradation of 14c-labelled dipterex in the buffer solutions and root tissues of broad bean and clover plants, as well as in the culture media of rhizobium leguminosarum and rhizobium trifolii. the formation of 14co2 from rhizobial cultures containing radioactive dipterex suggests that some of the liberated methanol groups (during breakdown of dipterex) are oxidat ... | 1975 | 1220485 |
| efficiency of rhizobium leguminosarum as affected by certain herbicides and nematocides. | | 1975 | 1243844 |
| a new subfamily of bacterial abc-type transport systems catalyzing export of drugs and carbohydrates. | sequence comparison studies revealed that the drug resistance transporter of streptomyces peucetius (drrab) and two nodulation gene products (nodij) of rhizobium leguminosarum are homologous to proteins encoded by three sets of genes that comprise capsular polysaccharide export systems in gram-negative bacteria: kpstm of escherichia coli, bexabc of haemophilus influenzae, and ctrdcb of neisseria meningitidis. these five systems comprise a new subfamily within the family of atp binding cassette ( ... | 1992 | 1303751 |
| rhizobium leguminosarum cfn42 lipopolysaccharide antigenic changes induced by environmental conditions. | four monoclonal antibodies were raised against the lipopolysaccharide of rhizobium leguminosarum bv. phaseoli cfn42 grown in tryptone and yeast extract. two of these antibodies reacted relatively weakly with the lipopolysaccharide of bacteroids of this strain isolated from bean nodules. growth ex planta of strain cfn42 at low ph, high temperature, low phosphate, or low oxygen concentration also eliminated binding of one or both of these antibodies. lipopolysaccharide mobility on gel electrophore ... | 1992 | 1312998 |
| the chloramphenicol acetyltransferase gene of tn2424: a new breed of cat. | we have sequenced the gene coding for the chloramphenicol acetyltransferase of tn2424 of plasmid nr79. this gene codes for a protein of 23,500 da, and the derived protein sequence is similar to those of the chromosomal chloramphenicol acetyltransferases of agrobacterium tumefaciens and pseudomonas aeruginosa and of unidentified open reading frames, which may encode chloramphenicol acetyltransferases, adjacent to the ermg macrolide-lincosamide-streptogramin resistance gene of bacillus sphaericus ... | 1992 | 1314803 |
| characterization of structural defects in the lipopolysaccharides of symbiotically impaired rhizobium leguminosarum biovar viciae vf-39 mutants. | the lipopolysaccharides (lps) of a wild type strain of rhizobium leguminosarum biovar viciae (strain vf-39) and two symbiotically defective tn5 mutants (vf-39-32 and vf-39-86) have been studied. the lps of the mutants reflected impaired synthesis of the o-antigen. in the lps of one mutant, the core tetrasaccharide was lacking and in that of the other it was truncated to a disaccharide containing mannose and 3-deoxy-d-manno-oct-2-ulosonic acid (kdo). the latter mutant also synthesized an unusual ... | 1992 | 1327527 |
| protein iiia of rhizobium leguminosarum is probably a porin. | the cloning, sequencing and expression of the gene encoding the 36-kilodalton (kda) outer membrane protein of rhizobium leguminosarum has been recently described in the literature (de maagd ra et al (1992) j bacteriol 174, 214-221). we present evidence that this protein is a porin from a sub-type covalently bound to the peptidoglycan. | 1992 | 1337982 |
| dissociation by nh4cl treatment of the enzymic activities of glutamine synthetase ii from rhizobium leguminosarum biovar viceae. | glutamine synthetase ii (gsii) was purified to homogeneity from rhizobium leguminosarum biovar viceae and characterized. the sequence of 26 amino acid residues from the amino-terminal end of the protein showed high similarity with the sequence of gsii from bradyrhizobium japonicum or from rhizobium meliloti. non-denaturing page showed that gsii, either in crude extracts or in the pure state, was a mixture of an octamer and a tetramer and that under specific conditions the octamer/tetramer ratio ... | 1992 | 1355107 |
| the rhizobium leguminosarum biovar phaseoli glnt gene, encoding glutamine synthetase iii. | plasmid pge203 contains the rhizobium leguminosarum biovar phaseoli glnt locus. glutamine synthetase iii (gsiii) was purified from a glutamine auxotrophic strain of klebsiella pneumoniae carrying this plasmid. sequencing of a 2.4-kb fragment containing the glnt locus reveals an open reading frame of 435 amino acids (aa), whose first eight aa are identical to those determined from pure gsiii by direct aa sequencing, thus confirming that glnt indeed codes for gsiii activity. the comparison of the ... | 1992 | 1356885 |
| activation of the rhizobium leguminosarum glnii gene by ntrc is dependent on upstream dna sequences. | the cloning and sequence determination is reported of the dna region of rhizobium leguminosarum coding for glutamine synthetase ii (gsii). an open reading frame (orf) encoding 326 amino acids was defined as the glnii gene on the basis of its similarity to other glnii genes and the ability of a dna fragment carrying this orf to complement the glutamine auxotrophy of a klebsiella pneumoniae glna mutant. we find that the glnii gene in r. leguminosarum is transcribed as a monocistronic unit from a s ... | 1992 | 1357539 |
| phenotype of a rhizobium leguminosarum ntrc mutant. | a tn5 insertion mutant, strain cfn2012, of rhizobium leguminosarum biovar phaseoli devoid of glutamine synthetase ii (gsii) activity was analysed. it was shown to contain tn5 within an 11-kb bamhi dna fragment, which was isolated (psm261) from the wild-type strain and, when introduced into strain cfn2012, was shown to complement the absence of gsii activity. the dna sequence of the corresponding region from the wild-type allele revealed the presence of an ntrc regulatory gene, and restriction an ... | 1992 | 1357726 |
| cloning, nucleotide sequencing, and expression in escherichia coli of a rhizobium leguminosarum gene encoding a symbiotically repressed outer membrane protein. | we describe the cloning of a gene from rhizobium leguminosarum biovar viciae strain 248 encoding protein iiia, the 36-kda outer membrane protein forming a part of the outer membrane protein antigen group iii. the expression of this antigen group is repressed in the bacteroid form during symbiosis (r. a. de maagd, r. de rijk, i. h. m. mulders, and b. j. j. lugtenberg, j. bacteriol. 171:1136-1142, 1989). a cosmid clone expressing the strain 248-specific mab38 epitope of this antigen group in a non ... | 1992 | 1370281 |
| phylogeny of fast-growing soybean-nodulating rhizobia support synonymy of sinorhizobium and rhizobium and assignment to rhizobium fredii. | we determined the sequences for a 260-base segment amplified by the polymerase chain reaction (corresponding to positions 44 to 337 in the escherichia coli 16s rrna sequence) from seven strains of fast-growing soybean-nodulating rhizobia (including the type strains of rhizobium fredii chemovar fredii, rhizobium fredii chemovar siensis, sinorhizobium fredii, and sinorhizobium xinjiangensis) and broad-host-range rhizobium sp. strain ngr 234. these sequences were compared with the corresponding pre ... | 1992 | 1371066 |
| chemical characterization of ph-dependent structural epitopes of lipopolysaccharides from rhizobium leguminosarum biovar phaseoli. | lipopolysaccharide (lps) was isolated from free-living rhizobium leguminosarum bv. phaseoli ce3 cells grown at ph 4.8 (antigenically similar to bacteroid lps) and compared with that from cells grown at ph 7.2 (free-living bacteria). composition analysis revealed that ph 7.2 lps differs from ph 4.8 lps in that 2,3,4-tri-o-methylfucose is replaced by 2,3-di-o-methylfucose. the amount of 2-o-methylrhamnose is greater in the ph 4.8 lps than in the ph 7.2 lps. analysis of the structural components of ... | 1992 | 1372601 |
| phylogenetic position of rhizobium sp. strain or 191, a symbiont of both medicago sativa and phaseolus vulgaris, based on partial sequences of the 16s rrna and nifh genes. | phenotypic and dna sequence comparisons are presented for eight rhizobium isolates that were cultured from field-grown alfalfa (medicago sativa l.) in oregon. these isolates were previously shown to nodulate both alfalfa and common bean (phaseolus vulgaris (l.) savi.). the objective of the present study was to determine their phylogenetic relationships to the normal symbionts of these plants, rhizobium meliloti and rhizobium leguminosarum biovar phaseoli, respectively. phenotypically, the oregon ... | 1992 | 1377901 |
| activation of flavonoid biosynthesis in roots of vicia sativa subsp. nigra plants by inoculation with rhizobium leguminosarum biovar viciae. | infective (nodulating) rhizobium leguminosarum biovar viciae (r.l. viciae) bacteria release nod factors which stimulate the release of nodulation gene-inducing flavanones and chalcones from roots of the host plant vicia sativa subsp. nigra (k. recourt et al., plant mol biol 16: 841-852; h.p. spaink et al., nature 354: 125-130). the hypothesis that this release results from increased synthesis of flavonoids was tested by studying the effect of inoculation of v. sativa with infective and uninfecti ... | 1992 | 1377964 |
| molecular dissection of structure and function in the lipopolysaccharide of rhizobium leguminosarum strain 3841 using monoclonal antibodies and genetic analysis. | following treatment with nitrosoguanidine, mutant derivatives of rhizobium leguminosarum strain 3841 were isolated which failed to react with afrc mac 203. this monoclonal antibody normally recognizes a strain-specific lipopolysaccharide epitope which is developmentally regulated during legume nodule differentiation. structural modification of lipopolysaccharide (lps) was analysed by examining reactivity with a range of monoclonal antibodies with different epitope specificities, and also by anal ... | 1992 | 1383672 |
| siderophore and organic acid production in root nodule bacteria. | nineteen strains of root nodule bacteria were grown under various iron regimes (0.1, 1.0 and 20 microm added iron) and tested for catechol and hydroxamate siderophore production and the excretion of malate and citrate. the growth response of the strains to iron differed markedly. for 12 strains (bradyrhizobium strains nc92b and 32h1, b. japonicum usda110 and cb1809, b. lupini wu8, cowpea rhizobium ngr234, rhizobium meliloti strains u45 and cc169, rhizobium leguminosarum bv viciae wu235 and rhizo ... | 1992 | 1387306 |
| the nodd protein does not bind to the promoters of inducible nodulation genes in extracts of bacteroids of rhizobium leguminosarum biovar viciae. | in a previous study, we showed that in bacteroids, transcription of the inducible nod genes does not occur and expression of nodd is decreased by 65% (h. r. m. schlaman, b. horvath, e. vijgenboom, r.j.h. okker, and b. j. j. lugtenberg, j. bacteriol. 173:4277-4287, 1991). in the present study, we show, using gel retardation, that in crude extracts of bacteroids of rhizobium leguminosarum biovar (bv.) viciae, nodd protein does not bind to the nodf, nodm, and nodo box and that it binds only weakly ... | 1992 | 1400160 |
| synthesis of cyclic beta-(1,2)-glucans by rhizobium leguminosarum biovar trifolii ta-1: factors influencing excretion. | the synthesis of cyclic beta-(1,2)-glucans from udp-[14c]glucose by a crude membrane preparation and whole cells of rhizobium leguminosarum bv. trifolii ta-1 was investigated. the crude membrane system needed mn2+, atp, and nad+ for optimal activity. hardly any difference in biosynthetic activity between membrane fractions of ta-1 cells grown in the presence (200 mm) or absence of nacl was observed. whole ta-1 cells grown in the presence of nacl excreted labeled, neutral cyclic beta-(1,2)-glucan ... | 1992 | 1400186 |
| effects of flavonoids released naturally from bean (phaseolus vulgaris) on nodd-regulated gene transcription in rhizobium leguminosarum bv. phaseoli. | nine flavonoid aglycones released from black bean (phaseolus vulgaris 'pi165426cs') seeds and roots induced nodc::lacz transcription in rhizobium leguminosarum bv. phaseoli strains containing extra cloned copies of the regulatory genes nodd1, nodd2, or nodd3 from that biovar. individual flavonoids generally induced highest levels of nodc::lacz transcription (imax) with extra copies of nodd2, and the concentration required for half-maximum induction (i50) was lowest with extra copies of nodd1 gen ... | 1992 | 1421508 |
| exopolysaccharides of rhizobium leguminosarum biovar trifolii harbouring cloned exo region. | rhizobium leguminosarum bv. trifolii produces an acidic exopolysaccharide (eps) which plays an important role in the development of nitrogen-fixing nodules. tn5 mutant of r. trifolii 93 defective in eps production (exo-) forms ineffective (fix-) nodules on red clover. this exo- mutation is complemented by the parf1368 and parf25 cosmids isolated from gene bank of rhizobium trifolii ta1, but the complementation is not correlated with restoration of fix+ phenotype. furthermore, these cosmids intro ... | 1992 | 1441845 |
| rhizobium nodm and nodn genes are common nod genes: nodm encodes functions for efficiency of nod signal production and bacteroid maturation. | earlier, we showed that rhizobium meliloti nodm codes for glucosamine synthase and that nodm and nodn mutants produce strongly reduced root hair deformation activity and display delayed nodulation of medicago sativa (baev et al., mol. gen. genet. 228:113-124, 1991). here, we demonstrate that nodm and nodn genes from rhizobium leguminosarum biovar viciae restore the root hair deformation activity of exudates of the corresponding r. meliloti mutant strains. partial restoration of the nodulation ph ... | 1992 | 1447128 |
| mutational analysis of pea lectin. substitution of asn125 for asp in the monosaccharide-binding site eliminates mannose/glucose-binding activity. | as part of a strategy to determine the precise role of pea (pisum sativum) lectin, psl, in nodulation of pea by rhizobium leguminosarum, mutations were introduced into the genetic determinant for pea lectin by site-directed mutagenesis using pcr. introduction of a specific mutation, n125d, into a central area of the sugar-binding site resulted in complete loss of binding of psl to dextran as well as of mannose/glucose-sensitive haemagglutination activity. as a control, substitution of an adjacen ... | 1992 | 1463840 |
| nucleotide sequence and organization of an h2-uptake gene cluster from rhizobium leguminosarum bv. viciae containing a rubredoxin-like gene and four additional open reading frames. | the nucleotide sequence of a 3.2 kb region following the hydrogenase structural operon (hupslcdef) in the h2-uptake gene cluster from rhizobium leguminosarum by viciae strain 128c53 has been determined. five closely linked genes encoding products of 16.3 (hupg), 30.5 (huph), 8.0 (hupi), 18.4 (hupj) and 38.7 (hupk) kda were identified 166 bp downstream from hupf. transposon insertions into hupg, huph, hupj and hupk suppress the h2-oxidizing capability of the wild-type strain. the amino acid seque ... | 1992 | 1469733 |
| evaluation of acidic heteropolysaccharide structures in rhizobium leguminosarum biovars altered in nodulation genes and host range. | 1h-nmr spectroscopy showed that the extracellular heterpolysaccharides (eps) from derivatives of rhizobium leguminosarum bv. trifolii anu843 altered in psym nod composition or function (transposon insertions, deletion of psym, induction by flavone, and introduction of cloned psym nod regions from anu843 and r. l. bv. viciae 248 on recombinant plasmids into the psym-cured background of anu843) differed only in 3-hydroxybutyrate stoichiometry per octaglycosyl unit. this change in eps was likely to ... | 1992 | 1477403 |
| characterisation of rhizobium isolates by amplification of dna polymorphisms using random primers. | the use of single random primers, selected in the absence of target sequence information, has been shown to be effective in producing dna amplifications that provide fingerprints which are unique to individual organisms. dna amplification by random priming was applied to the dna from isolates of rhizobium leguminosarum biovar trifolii. amplification products were produced using a number of primers, and the resulting fingerprints allowed strain differentiation. however, the effectiveness of prime ... | 1992 | 1477784 |
| the rhizobium leguminosarum fnrn protein is functionally similar to escherichia coli fnr and promotes heterologous oxygen-dependent activation of transcription. | an open reading frame from rhizobium leguminosarum bv. viciae strain vf39, previously identified and found to be similar to escherichia coli fnr and rhizobium meliloti fixk (orf240, thereafter called fnrn), was further analysed. analysis of the expression of an fnrn-lacz transcriptional fusion revealed that fnrn is preferentially expressed under oxygen limitation. using r. meliloti fixn-lacz fusions it was shown that the fnrn gene product only mediates transcriptional activation under microaerob ... | 1992 | 1484491 |
| slow rehydration improves the recovery of dried bacterial populations. | slow rehydration of bacteria from dried inoculant formulations provided higher viable counts than did rapid rehydration. estimates were higher when clay and peat powder formulations of rhizobium meliloti, rhizobium leguminosarum biovar trifolii, and pseudomonas putida, with water activities between 0.280 and 0.650, were slowly rehydrated to water activities of approximately 0.992 before continuing the dilution plating sequence. rhizobium meliloti populations averaged 6.8 x 10(8) cfu/g and 1328 c ... | 1992 | 1504917 |
| construction of a cassette enabling regulated gene expression in the presence of aromatic hydrocarbons. | a high-level expression cassette has been constructed from a tol plasmid derived from pseudomonas putida carrying all cis- and trans-acting regulatory elements necessary for transcriptional gene activation in the presence of aromatic hydrocarbons such as toluene. foreign dna can be inserted at unique kpni, saci, and ecori sites 7, 13, and 15 nucleotides downstream of a ribosome binding site. the cassette, flanked by bamhi and ecori restriction sites, was inserted into a broad-host-range vector a ... | 1992 | 1513877 |
| hierarchical analysis of linkage disequilibrium in rhizobium populations: evidence for sex? | many bacterial species exhibit strong linkage disequilibrium of their chromosomal genes, which apparently indicates restricted recombination between alleles at different loci. the extent to which restricted recombination reflects limited migration between geographically isolated populations versus infrequent mixis of genotypes within populations is more difficult to determine. we examined the genetic structure of rhizobium leguminosarum biovar phaseoli populations associated with wild and cultiv ... | 1992 | 1518873 |
| characterization of an aromatic amino acid aminotransferase from rhizobium leguminosarum biovar trifolii. | the most abundant aromatic amino acid aminotransferase of rhizobium leguminosarum biovar trifolii was partially purified. the molecular mass of the enzyme was estimated to be 53 kda by gel filtration. the enzyme transaminated aromatic amino acids and histidine. it used aromatic keto acids and alpha-ketoglutaric and oxalacetic acids as amino-group acceptors. the optimum temperature was 35 degrees c. using phenylalanine and alpha-ketoglutaric acid as substrates the activation energy was 46.2 kj.mo ... | 1992 | 1520732 |
| competition among rhizobium leguminosarum bv. phaseoli strains for nodulation of common bean. | six effective rhizobium leguminosarum bv. phaseoli strains were examined for nodulation competitiveness on common bean (phaseolus vulgaris l.), using all possible two-strain combinations of inoculum. nodule occupancy was determined with strain-specific fluorescent antibodies. the strains were divided into three groups according to their overall competitive abilities on pole bean cv. kentucky wonder and bush bean cv. bountiful. strains tal 182 and tal 1472 were highly competitive (greater than 70 ... | 1992 | 1521190 |
| major flavonoids in uninoculated and inoculated roots of vicia sativa subsp. nigra are four conjugates of the nodulation gene-inhibitor kaempferol. | inoculation of vicia sativa subsp. nigra (v. sativa) roots with rhizobium leguminosarum biovar. viciae (r.l. viciae) bacteria substantially increases the ability of v. sativa to induce rhizobial nodulation (nod) genes. this increase is caused by the additional release of flavanones and chalcones which all induce the nod genes of r.l. viciae (k. recourt et al., plant mol biol 16: 841-852). in this paper, we describe the analyses of the flavonoids present in roots of v. sativa. independent of inoc ... | 1992 | 1536926 |
| characterization of salt-tolerant and salt-sensitive mutants of rhizobium leguminosarum biovar viciae strain c1204b. | spontaneous mutants of rhizobium leguminosarum biovar viciae strain c1204b were selected for their ability to tolerate 0.2 m nacl, a growth-inhibiting level of salt for the parental strain. transposon-mediated salt-sensitive mutants of strain c1204b were screened for their inability to grow in 0.08 m nacl. quantitation of the free-amino acid pools in the mutants grown in nacl revealed a dramatic increase in glutamine, serine, glutamate and proline, and to a lesser extent alanine and glycine in t ... | 1992 | 1537541 |
| secretion of the rhizobium leguminosarum nodulation protein nodo by haemolysin-type systems. | the rhizobium leguminosarum biovar viciae nodulation protein nodo is partially homologous to haemolysin of escherichia coli and, like haemolysin, is secreted into the growth medium. the nodo protein can be secreted by a strain of e. coli carrying the cloned nodo gene plus the haemolysin secretion genes hlybd, in a process that also requires the outer membrane protein encoded by tolc. the related protease secretion genes, prtdef, from erwinia chrysanthemi also enable e. coli to secrete nodo. the ... | 1992 | 1545707 |
| molecular characterization and regulation of the rhizosphere-expressed genes rhiabcr that can influence nodulation by rhizobium leguminosarum biovar viciae. | a group of four rhi (rhizosphere-expressed) genes from the symbiotic plasmid of rhizobium leguminosarum biovar viciae has been characterized. although mutation of the rhi genes does not normally affect nodulation, in the absence of the closely linked nodulation genes nodfel, mutations in the rhi genes can influence the nodulation of the vetch vicia hirsuta. the dna sequence of the rhi gene region reveals four large open reading frames, three of them constituting an operon (rhiabc) transcribed co ... | 1992 | 1597418 |
| nucleotide sequence and characterization of four additional genes of the hydrogenase structural operon from rhizobium leguminosarum bv. viciae. | the nucleotide sequence of a 2.5-kbp region following the hydrogenase structural genes (hupsl) in the h2 uptake gene cluster from rhizobium leguminosarum bv. viciae upm791 was determined. four closely linked genes encoding peptides of 27.9 (hupc), 22.1 (hupd), 19.0 (hupe), and 10.4 (hupf) kda were identified immediately downstream of hupl. proteins with comparable apparent molecular weights were detected by heterologous expression of these genes in escherichia coli. the six genes, hups to hupf, ... | 1992 | 1597428 |
| rhizobium leguminosarum has two glucosamine synthases, glms and nodm, required for nodulation and development of nitrogen-fixing nodules. | the rhizobium leguminosarum nodm gene product shows strong homology to the escherichia coli glms gene product that catalyses the formation of glucosamine 6-p from fructose 6-p and glutamine. dna hybridization with nodm indicated that, in addition to nodm on the symbiotic plasmid, another homologous gene was present elsewhere in the r. leguminosarum genome. a glucosamine-requiring mutant was isolated and its auxotrophy could be corrected by two different genetic loci. it could grow without glucos ... | 1992 | 1602964 |
| identification of a nodd-like gene in frankia by direct complementation of a rhizobium nodd-mutant. | clones from a frankia at4 gene bank were pooled into groups and mass conjugated into a nodd mutant of rhizobium leguminosarum bv. viciae by triparental matings. when peas were inoculated with the pooled transconjugants, nodulation was observed. a plasmid, pat2gx containing frankia dna, was isolated from bacteria recovered from these nodules. this plasmid was shown to complement a nodd mutant of r. leguminosarum bv. viciae. thus pat2gx contains a frankia gene that is functionally equivalent to no ... | 1992 | 1603071 |
| influence of metribuzin on the rhizobium leguminosarum--lentil (lens culinaris) symbiosis. | the effects of the triazine herbicide metribuzin (sencor) on the lentil (lens culinaris medic.) - rhizobium leguminosarum biovar viciae symbiosis were studied in leonard jars and growth pouches. lentils inoculated with rhizobium leguminosarum strain 128c54 or 128c84, and noninoculated lentils grown in plant nutrient solution supplemented with 5 mm kno3, had metribuzin applied to the plants at either 8 or 13 days after planting. when sprayed at 8 days, metribuzin had a significant (p less than or ... | 1992 | 1611561 |
| cell-associated pectinolytic and cellulolytic enzymes in rhizobium leguminosarum biovar trifolii. | the involvement of rhizobium enzymes that degrade plant cell wall polymers has long been an unresolved question about the infection process in root nodule symbiosis. here we report the production of enzymes from rhizobium leguminosarum bv. trifolii that degrade carboxymethyl cellulose and polypectate model substrates with sensitive methods that reliably detect the enzyme activities: a double-layer plate assay, quantitation of reducing sugars with a bicinchoninate reagent, and activity gel electr ... | 1992 | 1622257 |
| hyperreiterated dna regions are conserved among bradyrhizobium japonicum serocluster 123 strains. | we have identified and cloned two dna regions which are highly reiterated in bradyrhizobium japonicum serocluster 123 strains. while one of the reiterated dna regions, pfr2503, is closely linked to the b. japonicum common and genotype-specific nodulation genes in strain usda 424, the other, pmap9, is located next to a tn5 insertion site in a host-range extension mutant of b. japonicum usda 438. the dna cloned in pfr2503 and pmap9 are reiterated 18 to 21 times, respectively, in the genomes of b. ... | 1992 | 1622264 |
| structure of the acidic exopolysaccharide secreted by rhizobium leguminosarum biovar. phaseoli cfn42. | | 1992 | 1633602 |
| combined subtraction hybridization and polymerase chain reaction amplification procedure for isolation of strain-specific rhizobium dna sequences. | a novel subtraction hybridization procedure, incorporating a combination of four separation strategies, was developed to isolate unique dna sequences from a strain of rhizobium leguminosarum bv. trifolii. sau3a-digested dna from this strain, i.e., the probe strain, was ligated to a linker and hybridized in solution with an excess of pooled subtracter dna from seven other strains of the same biovar which had been restricted, ligated to a different, biotinylated, subtracter-specific linker, and am ... | 1992 | 1637166 |
| different plasmids of rhizobium leguminosarum bv. phaseoli are required for optimal symbiotic performance. | rhizobium leguminosarum bv. phaseoli cfn42 contains six plasmids (pa to pf), and pd has been shown to be the symbiotic plasmid. to determine the participation of the other plasmids in cellular functions, we used a positive selection scheme to isolate derivatives cured of each plasmid. these were obtained for all except one (pe), of which only deleted derivatives were recovered. in regard to symbiosis, we found that in addition to pd, pb is also indispensable for nodulation, partly owing to the p ... | 1992 | 1644746 |
| polypeptide composition of bacterial cyclic diguanylic acid-dependent cellulose synthase and the occurrence of immunologically crossreacting proteins in higher plants. | to comprehend the catalytic and regulatory mechanism of the cyclic diguanylic acid (c-di-gmp)-dependent cellulose synthase of acetobacter xylinum and its relatedness to similar enzymes in other organisms, the structure of this enzyme was analyzed at the polypeptide level. the enzyme, purified 350-fold by enzyme-product entrapment, contains three major peptides (90, 67, and 54 kda), which, based on direct photoaffinity and immunochemical labeling and amino acid sequence analysis, are constituents ... | 1991 | 1647035 |
| polygalacturonase is a virulence factor in agrobacterium tumefaciens biovar 3. | agrobacterium tumefaciens biovar 3 causes both crown gall and root decay of grapes. all biovar 3 strains, regardless of their tumorigenicity, produce in culture a single polygalacturonase with a pi around 4.5. a. tumefaciens biovar 3 strain cg49 was mutagenized with tn5 by using psup2021 as a suicide vector. a mutant strain, cg50, lacking polygalacturonase activity was isolated. the mutation was due to a single tn5 insertion in an 8.5-kb ecori fragment that also contained the polygalacturonase s ... | 1991 | 1655716 |
| a cultivar-specific interaction between rhizobium leguminosarum bv. trifolii and subterranean clover is controlled by nodm, other bacterial cultivar specificity genes, and a single recessive host gene. | insertion mutagenesis identified two negatively acting gene loci which restrict the ability of rhizobium leguminosarum bv. trifolii ta1 to infect the homologous host trifolium subterraneum cv. woogenellup. one locus was confirmed by dna sequence analysis as the nodm gene, while the other locus, designated csn-1 (cultivar-specific nodulation), is not located on the symbiosis plasmid. the presence of these cultivar specificity loci could be suppressed by the introduction of the nodt gene from anu8 ... | 1991 | 1673458 |
| production and epitope analysis of monoclonal antibodies against a rhizobium leguminosarum biovar trifolii strain. | heat-treated cells of rhizobium leguminosarum biovar trifolii strain 162x95 were used to produce monoclonal antibodies (mabs). the fusion produced three cross-reactive mabs and eight mabs specific for the immunizing strain and a group of five other r. trifolii strains from the same geographic region where 162x95 was isolated (california). seven mabs were analyzed by competitive enzyme-linked immunosorbent assay to determine the number of different epitopes detectable on strain 162x95. the result ... | 1990 | 1697150 |
| genetic structure of a soil population of nonsymbiotic rhizobium leguminosarum. | the genetic structure of a population of nonsymbiotic rhizobium leguminosarum strains was determined by the electrophoretic mobilities of eight metabolic enzymes. nonsymbiotic strains were isolated from the rhizosphere of bean plants and characterized by growth on differential media and at different temperatures, intrinsic antibiotic resistance, the lack of homology to a nifh probe, and their inability to form nodules on bean roots. all the isolates clustered with r. leguminosarum bv. phaseoli r ... | 1991 | 1707606 |
| antigenic changes in lipopolysaccharide i of rhizobium leguminosarum bv. viciae in root nodules of vicia sativa subsp. nigra occur during release from infection threads. | three different monoclonal antibodies raised against the o antigen-containing lipopolysaccharide (lps i) of free-living cells were used in an immunocytochemical study to follow the fate of lps i on the outer membrane of rhizobium leguminosarum bv. viciae 248 during the nodulation of vicia sativa subsp. nigra. after immunogold labeling, the lps i epitopes were detected on the outer membrane of bacteria present in infection threads throughout the nodule. epitopes were not detectable on bacteria re ... | 1991 | 1708764 |
| suppression of nodulation gene expression in bacteroids of rhizobium leguminosarum biovar viciae. | the expression of nod genes of rhizobium leguminosarum bv. viciae in nodules of pisum sativum was investigated at both the translational and transcriptional levels. by using immunoblots, it was found that the levels of noda, nodi, node, and nodo proteins were reduced at least 14-fold in bacteriods compared with cultured cells, whereas nodd protein was reduced only 3-fold. northern (rna) blot hybridization, rnase protection assays, and in situ rna hybridization together showed that, except for th ... | 1991 | 1712355 |
| rhizobium tropici, a novel species nodulating phaseolus vulgaris l. beans and leucaena sp. trees. | a new rhizobium species that nodulates phaseolus vulgaris l. and leucaena spp. is proposed on the basis of the results of multilocus enzyme electrophoresis, dna-dna hybridization, an analysis of ribosomal dna organization, a sequence analysis of 16s rdna, and an analysis of phenotypic characteristics. this taxon, rhizobium tropici sp. nov., was previously named rhizobium leguminosarum biovar phaseoli (type ii strains) and was recognized by its host range (which includes leucaena spp.) and nif ge ... | 1991 | 1715738 |
| the oac gene encoding a lipopolysaccharide o-antigen acetylase maps adjacent to the integrase-encoding gene on the genome of shigella flexneri bacteriophage sf6. | lysogens of shigella flexneri harbouring the temperate bacteriophage, sf6, have been previously shown to undergo a serotype conversion due to o-acetylation of the o-antigen of the lipopolysaccharide. a partial physical map of the phage genome has been constructed. analysis of the phage dna suggests that the phage packages by a headful mechanism and that the mature dna molecules are terminally redundant. cloning of the psti fragments of sf6 enabled the region encoding the serotype conversion to b ... | 1991 | 1720755 |
| biological activity of rhizobial siderophore. | non-nodulating mutant of rhizobium leguminosarum biovar trifolli produces the phenolate type of siderophore consisting of 2,3-dihydroxybenzoic acid and threonine. the activity of this compound against the various bacteria was tested. only, the growth of r. leguminosarum strains was stimulated by siderophore. the other species of rhizobium, especially r. meliloti, were sensitive to this agent. the growth of r. meliloti was also inhibited by agrobactin and pseudobactin. this effect was reversed by ... | 1991 | 1726625 |
| the central domain of rhizobium leguminosarum dctd functions independently to activate transcription. | sigma 54-dependent transcriptional activators such as escherichia coli ntrc, rhizobium meliloti nifa, and rhizobium leguminosarum dctd share similar central and carboxy-terminal domains but differ in the structure and function of their amino-terminal domains. we have deleted the amino-terminal and carboxy-terminal domains of r. leguminosarum dctd and have demonstrated that the central domain of dctd, like that of nifa, is transcriptionally competent. | 1992 | 1735730 |
| autoregulatory response of phaseolus vulgaris l. to symbiotic mutants of rhizobium leguminosarum bv. phaseoli. | in rhizobium-legume symbiosis, the plant host controls and optimizes the nodulation process by autoregulation. tn5 mutants of rhizobium leguminosarum bv. phaseoli tal 182 which are impaired at various stages of symbiotic development, were used to examine autoregulation in the common bean (phaseolus vulgaris l.). class i mutants were nonnodulating, class ii mutants induced small, distinct swellings on the roots, and a class iii mutant formed pink, bacterium-containing, but ineffective nodules. a ... | 1991 | 1768143 |
| identification of a nifa-like regulatory gene of azospirillum brasilense sp7 expressed under conditions of nitrogen fixation and in the presence of air and ammonia. | a gene bank of azospirillum lipoferum br17 constructed in the vector lambda gem11 was screened with a bradyrhizobium japonicum nifa gene probe. a 7.3 kb ecori fragment carrying a nifa-like gene was thereby isolated and subsequently used to screen a gene bank of azospirillum brasilense sp7 constructed in puc18. two ecori fragments of 5.6 kb and 3.6 kb covering the nifa-homology region were found. mutants with nif- phenotype were obtained by site-directed tn5 mutagenesis of the 5.6 kb fragment and ... | 1991 | 1779763 |
| the rhizobium meliloti exozl exob fragment of megaplasmid 2: exob functions as a udp-glucose 4-epimerase and exoz shows homology to nodx of rhizobium leguminosarum biovar viciae strain tom. | a 2.6 kb clai-bamhi dna fragment of megaplasmid 2 of rhizobium meliloti 2011 was found to carry genes involved in exopolysaccharide synthesis and infection of alfalfa nodules. the analysis of the nucleotide sequence of this dna fragment revealed the existence of two open reading frames (orfs) running in opposite directions. plasmid integration mutagenesis showed that these orfs are organized as two monocistronic transcription units. one of the orfs represents a new exo gene designated exoz, whic ... | 1991 | 1787800 |
| unusual structure of the exopolysaccharide of rhizobium leguminosarum bv. viciae strain 248. | the exopolysaccharide from r. leguminosarum bv. viciae strain 248 differs from those of other rhizobium strains with similar symbiotic behavior. 13c-n.m.r. spectroscopy of fragments generated by partial hydrolysis, together with methylation analysis and 13c-n.m.r. spectroscopy of the enzymically depolymerised exopolysaccharide, indicated the following nonasaccharide repeating-unit: [formula: see text] the locations of the acetyl and 3-hydroxybutanoyl substituents in the exopolysaccharide are ass ... | 1991 | 1802384 |
| identification of 3-deoxy-lyxo-2-heptulosaric acid in the core region of lipopolysaccharides from rhizobiaceae. | a 3-deoxy-2-heptulosaric acid (dha), very probably with the lyxo-configuration, was identified in the r-core region of lipopolysaccharides from nodulating strains of rhizobium leguminosarum, rhizobium meliloti and from all three biovars of the phytopathogenic agrobacterium tumefaciens. its structure could be deduced from the fragmentation pattern of the corresponding alditol acetates obtained after reduction of the 2-keto and the 1.7-carboxy groups by sodium borohydride or sodium borodeuteride. ... | 1991 | 1804765 |
| re-examination of the structures of the lipopolysaccharide core oligosaccharides from rhizobium leguminosarum biovar phaseoli. | | 1991 | 1811857 |
| the region for exopolysaccharide synthesis in rhizobium leguminosarum biovar trifolii is located on the non-symbiotic plasmid. | an exo- mutant of rhizobium leguminosarum biovar trifolii was isolated which did not produce acidic exopolysaccharide and induced defective, non-fixing nodules on clover plants. the nodules were defective at a late stage of development, they contained infection threads and bacteria were released into the host cells. cosmid parf136 capable of complementing the exo- mutation was isolated from a cosmid bank made from total r. trifolii dna. hybridization between dna of parf136 and plasmids of r. tri ... | 1991 | 1814135 |
| sequence and structural organization of a nif a-like gene and part of a nifb-like gene of herbaspirillum seropedicae strain z78. | the deduced amino acid sequence derived from the sequence of a fragment of dna from the free-living diazotroph herbaspirillum seropedicae was aligned to the homologous protein sequences encoded by the nifa genes from azorhizobium caulinodans, rhizobium leguminosarum, rhizobium meliloti and klebsiella pneumoniae. high similarity was found in the central domain and in the c-terminal region. the h. seropedicae putative nifa sequence was also found to contain an interdomain linker similar to that co ... | 1991 | 1840608 |
| identification of nolr, a negative transacting factor controlling the nod regulon in rhizobium meliloti. | in rhizobium meliloti, expression of the nodulation genes (nod and nol genes) is under both positive and negative controls. these genes are activated by the products of the three related nodd genes, in conjunction with signal molecules from the host plants. we showed that negative regulation is mediated by a repressor protein, binding to the overlapping nodd1 and noda as well as to the nodd2 promoters. the encoding gene, termed nolr, was identified and cloned from strain 41. by subcloning, delet ... | 1991 | 1840615 |
| comparative response of pisum sativum nodulated with indigenous soil rhizobium populations and/or co-inoculated with a rhizobium leguminosarum strain. i. acetylene-reducing, dihydrogen- and carbon dioxide-evolving activities. | no significant differences in the acetylene-reducing activity and evolution of h2 and co2 from nodulated roots of pisum sativum inoculated with soil rhizobium populations from two soils with different acidities (ruzynĕ soil 7.6; lukavec soil 4.9) were observed. rhizobium population from lukavec soil formed nodules, exhibiting a higher h2 evolution. co-inoculation with the hup+ strain 128c30 (7 x 10(7) cells per seedling) eliminated, to some extent, the effect of soil populations on physiological ... | 1991 | 1841862 |
| inoculation of vicia sativa subsp. nigra roots with rhizobium leguminosarum biovar viciae results in release of nod gene activating flavanones and chalcones. | flavonoids released by roots of vicia sativa subsp. nigra (v. sativa) activate nodulation genes of the homologous bacterium rhizobium leguminosarum biovar viciae (r. l. viciae). inoculation of v. sativa roots with infective r. l. viciae bacteria largely increases the nod gene-inducing ability of v. sativa root exudate (a.a.n. van brussel et al., j bact 172: 5394-5401). the present study showed that, in contrast to sterile roots and roots inoculated with r. l. viciae cured of its sym plasmid, roo ... | 1991 | 1859867 |
| nodt, a positively-acting cultivar specificity determinant controlling nodulation of trifolium subterraneum by rhizobium leguminosarum biovar trifolii. | rhizobium leguminosarum biovar trifolii strain ta1 nodulates a range of trifolium plants including red, white and subterranean clovers. nitrogen-fixing nodules are promptly initiated on the tap roots of these plants at the site of inoculation. in contrast to these associations, strain ta1 has a 'nod-' phenotype on a particular cultivar of subterranean clover called woogenellup (a.h. gibson, aust j agric sci 19: (1968) 907-918) where it induces rare, poorly developed, slow-to-appear and ineffecti ... | 1991 | 1868196 |
| rhizobium lipopolysaccharide modulates infection thread development in white clover root hairs. | the interaction between rhizobium lipopolysaccharide (lps) and white clover roots was examined. the limulus lysate assay indicated that rhizobium leguminosarum bv. trifolii (hereafter called r. trifolii) released lps into the external root environment of slide cultures. immunofluorescence and immunoelectron microscopy showed that purified lps from r. trifolii 0403 bound rapidly to root hair tips and infiltrated across the root hair wall. infection thread formation in root hairs was promoted by p ... | 1991 | 1885517 |
| regulation of phenolic catabolism in rhizobium leguminosarum biovar trifolii. | in members of the family rhizobiaceae, many phenolic compounds are degraded by the protocatechuate branch of the beta-ketoadipate pathway. in this paper we describe a novel pattern of induction of protocatechuate (pca) genes in rhizobium leguminosarum biovar trifolii. isolation of pca mutant strains revealed that 4-hydroxybenzoate, quinate, and 4-coumarate are degraded via the protocatechuate pathway. at least three inducers govern catabolism of 4-hydroxybenzoate to succinyl coenzyme a and acety ... | 1991 | 1885531 |
| characterization of reca genes and reca mutants of rhizobium meliloti and rhizobium leguminosarum biovar viciae. | dna fragments carrying the reca genes of rhizobium meliloti and rhizobium leguminosarum biovar viciae were isolated by complementing a uv-sensitive reca- escherichia coli strain. sequence analysis revealed that the coding region of the r. meliloti reca gene consists of 1044 bp coding for 348 amino acids whereas the coding region of the r. leguminosarum bv. viciae reca gene has 1053 bp specifying 351 amino acids. the r. meliloti and r. leguminosarum bv. viciae reca genes show 84.8% homology at th ... | 1991 | 1896024 |
| six nodulation genes of nod box locus 4 in rhizobium meliloti are involved in nodulation signal production: nodm codes for d-glucosamine synthetase. | the nucleotide sequence of the nod box locus n4 in rhizobium meliloti was determined and revealed six genes organized in a single transcriptional unit, which are induced in response to a plant signal such as luteolin. mutations in these genes influence the early steps of nodule development on medicago, but have no detectable effect on melilotus, another host for r. meliloti. based on sequence homology, the first open reading frame (orf) corresponds to the nodm gene and the last to the nodn gene ... | 1991 | 1909418 |