Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| a rhizobium meliloti mutant that forms ineffective pseudonodules in alfalfa produces exopolysaccharide but fails to form beta-(1----2) glucan. | a mutant of rhizobium meliloti that elicited the formation of inactive nodules in alfalfa was found not to form beta-(1----2) glucan in vivo or in vitro. it was nonmotile because it lacks flagella. the 235-kilodalton protein which acts as an intermediate in beta-(1----2) glucan synthesis was undetectable in the mutant. these properties of the mutant are common to those of chvb mutants of agrobacterium tumefaciens. exopolysaccharide formation by the r. meliloti mutant was about double that by the ... | 1987 | 3804979 |
| the promoter proximal region in the vird locus of agrobacterium tumefaciens is necessary for the plant-inducible circularization of t-dna. | the formation of crown gall tumours involves the transfer of the t-dna region of the ti plasmid from agrobacterium to plant cells and its subsequent integration into plant chromosomes. when agrobacteria are incubated with plant protoplasts or exudates of plants, the t-dna region is circularized by recombination or cleavage and rejoining between the 25 bp terminal repeats; the formation of circular t-dnas is thought to be one step in t-dna transfer (koukolikova-nicola et al. 1985; machida et al. ... | 1987 | 3472033 |
| nodulin-26, a peribacteroid membrane nodulin is expressed independently of the development of the peribacteroid compartment. | the peribacteroid membrane (pbm) of root nodules is derived from the plant cell plasma membrane but contains in addition several nodule-specific host proteins (nodulins). antibodies raised against purified pbm of soybean were used to immunoprecipitate polysomes to isolate an rna fraction that served as a template for the synthesis of a cdna probe for screening a nodule-specific cdna library. clone p1b1 was found to encode a 26.5 kda polypeptide (nodulin-26) which is immunoprecipitable specifical ... | 1987 | 3822816 |
| phospholipids and proteins from rhizobium meliloti exposed to parathion at different incubation times. | 1987 | 3814848 | |
| effects of rhizobium meliloti nif and fix mutants on alfalfa root nodule development. | ineffective alfalfa nodules were examined at the light and electron microscope level after inoculation with rhizobium meliloti strains with mutations in nif and fix genes. all the mutant strains induced nodules that contained elongated bacteroids within the host cells, but the bacteroids quickly senesced. the nodules were small and numerous, and the host cells also exhibited symptoms of an ineffective symbiosis. nifb, fixa, and fixb bacteroids appeared to be completely differentiated (by ultrast ... | 1987 | 3818542 |
| agrobacterium rhizogenes as a vector for transforming higher plants. | agrobacterium rhizogenes is a natural vector for genetically transforming higher plants. a protocol is given for using this system to insert foreign genes into host plants. improvements currently being developed in several laboratories are also discussed. | 1987 | 3153165 |
| transcription patterns of rhizobium meliloti symbiotic plasmid psym: identification of nifa-independent fix genes. | we performed a systematic survey of transcription of a large region of the rhizobium meliloti symbiotic plasmid psym. this led to the discovery of two new sequences induced during symbiosis. the first sequence was linked to the known nitrogen fixation (nif-fix) gene cluster, and its expression depended on the nifa gene product. the second sequence was a novel fix locus (m.-h. renalier, j. batut, j. ghai, b. terzaghi, m. gherardi, m. david, a.-m. garnerone, j. vasse, g. truchet, t. huguet, and p. ... | 1987 | 2437100 |
| the nifa gene of rhizobium meliloti is oxygen regulated. | experiments using plasmid-borne gene fusions and direct rna measurements have revealed that expression from the nifa gene is induced in rhizobium meliloti when the external oxygen concentration is reduced to microaerobic levels. induction occurs in the absence of alfalfa and in the presence of fixed nitrogen and does not require ntrc. the production of functional nifa gene product (nifa) can be demonstrated by its ability to activate the nitrogenase promoter p1. aerobic induction of nifa can als ... | 1987 | 2439489 |
| use of tannic acid for the ultrastructural visualization of periplasm in gram-negative bacteria. | tannic acid mordanting reveals the periplasm, the area between the outer membrane and the inner membrane of gram-negative bacteria, rhizobium sp., escherichia coli and enterobacter aerogenes, as an electron-dense layer continuous with the inner leaflet of the outer membrane. the method involves 18 hr of tannic acid treatment after fixation in aldehyde prior to osmium tetroxide postfixation, followed by conventional electron microscopy. | 1987 | 2440153 |
| nucleotide sequence of a trna(leu)cag gene from rhizobium meliloti. | the nucleotide sequence of a trna(leu)cag gene from rhizobium meliloti has been determined. its organization includes a short transcript with a promoter-like structure and two rho-independent terminators about 10 bp downstream from the cloverleaf structure. the putative promoter shows good homology with the -45 and -35 region of the consensus (sigma 70) promoter sequence of escherichia coli, but less with the -10 region. a discriminator-like sequence is present between the start of the transcrip ... | 1987 | 2442068 |
| genetic analysis of agrocin 84 production and immunity in agrobacterium spp. | mutations affecting agrocin production on the 48-kilobase (kb) plasmid, pagk84, can be complemented in trans with cloned portions of the plasmid. five complementation groups ranging in minimum size from 1.2 to 5.6 kb were identified within a 14-kb segment. plasmid pagk84-encoded immunity to agrocin 84 was located to two separate regions of the plasmid. either region alone was sufficient to protect sensitive strains, and both loci mapped to the agrocin 84 biosynthesis region. one region is locate ... | 1987 | 2442139 |
| genes responsible for the supervirulence phenotype of agrobacterium tumefaciens a281. | agrobacterium tumefaciens a281 induces large, rapidly appearing tumors on a variety of plants and has a wider host range than other strains of a. tumefaciens. by using tn3hoho1 transposon mutagenesis and complementation analysis, a 2.5-kilobase dna fragment which is responsible for the supervirulence phenotype was identified in the virulence (vir) region of the ti plasmid. this fragment contains the virg locus, as well as the 3' end of the virb operon. a clone of this fragment conferred the supe ... | 1987 | 2443480 |
| relationship between raman spectroscopic lines and growth of rhizobium japonicum. | the raman spectroscopic lines of liquid cultures of rhizobium japonicum have been compared with electron microscopic examinations and growth measurements of these cells. the results showed that the significant raman lines are related to the reproduction activities of the procaryotic cells. | 1987 | 2446767 |
| indoleacetic acid production by rhizobium sp. from a leguminous tree, erythrina indica. | rhizobium sp. isolated from the root nodules of erythrina indica lamk., a leguminous tree, produced large amounts of indoleacetic acid (iaa) from tryptophan. l-tryptophan (2 mg/ ml) was preferred to dl-tryptophan for iaa synthesis. attempts were made to optimize the cultural requirements for an accelerated iaa production. an enrichment of the carbon-free incubation medium with maltose (1 %), mnso4 x h2o (5 microg/ml), and triton x-100 (100 ppm) promoted the synthesized iaa content of the medium ... | 1987 | 18425685 |
| extended region of nodulation genes in rhizobium meliloti 1021. i. phenotypes of tn5 insertion mutants. | rhizobium meliloti nod(-) mutant wl131, a derivative of wild-type strain 102f51, was complemented by a clone bank of wild-type r. meliloti 1021 dna, and clone prmjt5 was recovered. transfer of prmjt5 conferred alfalfa nodulation on other rhizobium species, indicating a role in host range determination for prmjt5. mutagenesis of prmjt5 revealed several segments in which transposon insertion causes delay in nodulation, and/or marked reduction of the number of nodules formed on host alfalfa plants. ... | 1987 | 17246399 |
| extended region of nodulation genes in rhizobium meliloti 1021. ii. nucleotide sequence, transcription start sites and protein products. | we have established the dna sequence and analyzed the transcription and translation products of a series of putative nodulation (nod) genes in rhizobium meliloti strain 1021. four loci have been designated nodf, node, nodg and nodh. the correlation of transposon insertion positions with phenotypes and open reading frames was confirmed by sequencing the insertion junctions of the transposons. the protein products of these nod genes were visualized by in vitro expression of cloned dna segments in ... | 1987 | 17246400 |
| absence in monocotyledonous plants of the diffusible plant factors inducing t-dna circularization and vir gene expression in agrobacterium. | t-dna circularization is one of the molecular events specifically induced in agrobacterial cells upon their infection of dicotyledonous plant cells. we developed a seedling co-cultivation procedure to determine whether or not monocotyledonous plants have the ability to induce t-dna circularization and vir gene expression. co-cultivation of agrobacterium tumefaciens with seedlings of dicotyledonous plants showed that the circularization event takes place efficiently. the exudates and extracts of ... | 1987 | 17191337 |
| the ntrc gene of agrobacterium tumefaciens c58 controls glutamine synthetase (gsii) activity, growth on nitrate and chromosomal but not ti-encoded arginine catabolism pathways. | the ntrc locus of agrobacterium tumefaciens c58 has been cloned using the azorhizobium sesbaniae ors571 ntrc gene as a dna hybridization probe. transposon tn5 mutagenesis of the cloned ntrc locus was carried out and one tn5 insertion within the region of highest dna homology with a. sesbaniae ors571 ntrc was used for gene replacement of the wild-type c58 ntrc gene. the a. tumefaciens ntrc::tn5 mutant was found to be unable to grow on nitrate as sole nitrogen (n) source, to lack glutamine synthet ... | 1987 | 17193704 |
| agrobacterium rhizogenes t-dna genes capable of inducing hairy root phenotype. | segments of the tl-dna of the agropine type ri plasmid pri 1855 encompassing single and groups of open-reading frames were cloned in the ti plasmid-derived binary vector system bin 19. leaf disc infections on nicotiana tabacum led to transformed plants, some of which showed typical hairy root phenotypes, such as the wrinkled leaf morphology, excessive and partially non geotropic root systems and the ability of leaf explants to differentiate roots in a hormone-free culture medium. particularly in ... | 1987 | 17193709 |
| a plasmid sequence from rhizobium leguminosarum 300 contains homology to sequences near the octopine tl-dna right border. | the dna sequence from a rhizobium leguminosarum 300 (rl300) plasmid that contains homology to the tc-dna of agrobacterium tumefaciens is described. the rl300 sequence has 78% homology to a 359 bp sequence in the tc-dna of pti15955. the rl300 homology starts approximately 100 bp from the 24 bp border sequence of the tl-dna and ends approximately 3 bp from an is66 homolog in the tc-dna. an unusual feature of the rl300 homology is the presence of 81 bp direct repeats with tc-dna homology, separated ... | 1987 | 17193713 |
| two host-inducible genes of rhizobium fredii and characterization of the inducing compound. | random transcription fusions with mu d1(kan lac) generated three mutants in rhizobium fredii (strain usda 201) which showed induction of beta-galactosidase when grown in root exudate of the host plants glycine max, phaseolus vulgaris, and vigna ungliculata. two genes were isolated from a library of total plasmid dna of one of the mutants, 3f1. these genes, present in tandem on a 4.2-kilobase hindiii fragment, appear in one copy each on the symbiotic plasmid and do not hybridize to the rhizobium ... | 1988 | 2447061 |
| expression of an agrobacterium ti plasmid gene involved in cytokinin biosynthesis is regulated by virulence loci and induced by plant phenolic compounds. | the nopaline-type ti plasmid t37 of agrobacterium tumefaciens carries two distinct genes that encode enzymes involved in cytokinin biosynthesis. in this report, we show that the level of expression of one of these genes was increased dramatically by culture conditions that increased the expression of ti plasmid virulence genes, including coculture with plant cells or treatment with acetosyringone, a plant phenolic compound. when this nopaline-type ti plasmid gene was introduced into agrobacteriu ... | 1988 | 2448293 |
| functioning haemoglobin genes in non-nodulating plants. | haemoglobin has previously been recorded in plants only in the nitrogen-fixing nodules formed by symbiotic association between rhizobium or frankia and legume or non-legume hosts. structural similarities amongst these and animal haemoglobins at the protein and gene level suggested a common evolutionary origin. this suggests that haemoglobin genes, inherited from an ancestor common to plants and animals, might be present in all plants. we report here the isolation of a haemoglobin gene from trema ... | 1988 | 2448639 |
| rhizobium fix genes mediate at least two communication steps in symbiotic nodule development. | to identify bacterial genes involved in symbiotic nodule development, ineffective nodules of alfalfa (medicago sativa) induced by 64 different fix-mutants of rhizobium meliloti were characterized by assaying for symbiotic gene expression and by morphological studies. the expression of leghemoglobin and nodulin-25 genes from alfalfa and of the nifhd genes from r. meliloti were monitored by hybridizing the appropriate dna probes to rna samples prepared from nodules. the mutants were accordingly di ... | 1988 | 2450096 |
| nucleotide sequence and genetic analysis of the nifb-nifq region from azotobacter vinelandii. | a 3.8-kilobase-pair ecori fragment which corrects the mutations carried by the nifb- azotobacter vinelandii strains ca30 and uw45 was cloned, and its nucleotide sequence was determined. four complete open reading frames (orfs) and two partial orfs were found. the translation product of the first partial orf is the carboxy-terminal end of a protein homologous to the nifa gene product from klebsiella pneumoniae. a 285-base-pair sequence containing a potential nif promoter and nif regulatory sites ... | 1988 | 2450865 |
| agrobacterium tumefaciens vire operon encodes a single-stranded dna-binding protein. | the virulence (vir) genes of agrobacterium tumefaciens ti plasmid are essential for transformation of plant cells. overproduction of a vire-encoded gene product in escherichia coli was achieved by construction of an operon fusion with the e. coli tryptophan (trp) operon. the vire2 gene product in e. coli partitioned into the insoluble membrane fraction. the protein was solubilized by treatment with 4 m urea at 0 degree c. dna-protein binding experiments showed that a strong single-stranded (ss) ... | 1988 | 2452439 |
| selective recovery of foreign gene transcripts as virus-like particles in tmv-infected transgenic tobaccos. | a short origin-of-assembly sequence (oas) located in the 30kda movement protein gene, about 1.0kb from the 3'-end of the common strain of tobacco mosaic virus (tmv) rna, nucleates encapsidation of the 6395-nucleotide-long genome by tmv coat protein in vitro, and presumably also in vivo. single-stranded rnas containing a foreign reporter gene sequence and the tmv oas at their 5' - and 3' -ends, respectively, can be synthesized in vitro from recombinant sp6-transcription plasmids and will assemble ... | 1988 | 2453837 |
| [branching enzyme from rhizobium lupini bacteroids as a nucleoprotein: the role of rna in the complex with protein component and after its removal]. | 1988 | 2454184 | |
| use of agrobacterium radiobacter in agricultural ecosystems. | agrobacterium tumefaciens is a soil inhabitant that infects many dicotyledonous plants, causing crown gall disease. the success of agrobacterium radiobacter k84 to control this disease in agroecosystems throughout the world has been impressive. this review describes the attributes of k84, its mechanism of control, its failures, and other alternative biocontrol agents. | 1988 | 3079224 |
| all nod genes of rhizobium meliloti are involved in alfalfa nodulation by exo mutants. | nodulation of alfalfa by exob mutants of rhizobium meliloti occurred without root hair curling or infection thread formation. nod exob double mutants had the same nodulation deficiency as single nod mutants. therefore, all the known nod genes are involved in nodule induction by exob mutants, which apparently occurs via intercellular invasion. | 1988 | 3338972 |
| root nodule specific gene regulation: analysis of the soybean nodulin n23 gene promoter in heterologous symbiotic systems. | the nodulin n23 gene promoter was analysed in transgenic plants using the chloramphenicol acetyltransferase (cat) coding sequence as a reporter. a 5' flanking region of less than 1 kb was sufficient for the organ-specific expression of a chimeric n23-cat-3'lbc3 gene in root nodules formed on lotus corniculatus and trifolium repens after infection by their respective rhizobium symbionts. expression was regulated at the level of rna in both species of transgenic plants. promoter deletion analysis ... | 1988 | 3340542 |
| agrobacterium-mediated infectivity of cloned digitaria streak virus dna. | a monomeric clone of double-stranded dna synthesized in vitro dna of the geminivirus digitaria streak (dsv) was subcloned as a tandem dimeric unit into a binary vector of agrobacterium tumefaciens, creating a plasmid pds2. inoculation of digitaria sanguinalis with a. tumefaciens carrying pds2 resulted in viral infection. the symptoms, virus particles, and dna forms obtained were indistinguishable from those of a natural dsv infection of d. sanguinalis. inoculations have also induced infections i ... | 1988 | 3341112 |
| genomic instability in rhizobium phaseoli. | experience from different laboratories indicates that rhizobium strains can generate variability in regard to some phenotypic characteristics such as colony morphology or symbiotic properties. on the other hand, several reports suggest that under certain stress conditions or genetic manipulations rhizobium cells can present genomic rearrangements. in search of frequent genomic rearrangements, we analyzed three rhizobium strains under laboratory conditions that are not considered to cause stress ... | 1988 | 3343217 |
| the complete structure of the trifoliin a lectin-binding capsular polysaccharide of rhizobium trifolii 843. | the complete structure of the acidic, extracellular, capsular polysaccharide of rhizobium trifolii 843 has been elucidated by a combination of chemical, enzymic, and spectroscopic methods, confirming an earlier proposed sugar sequence and assigning the locations of the acyl substituents. the polysaccharide was depolymerized by a lyase into octasaccharide units which were uniform in carbohydrate composition and linkage. these units also contained a uniform distribution of acetyl and pyruvic aceta ... | 1988 | 3349503 |
| a case of septicaemia caused by agrobacterium radiobacter. | 1988 | 3351321 | |
| proline metabolism in n2-fixing root nodules: energy transfer and regulation of purine synthesis. | n2-fixing root nodules of soybean (glycine max l. merr.) convert atmospheric n2 to ammonia(um) in an energy-intensive enzymatic reaction. these nodules synthesize large quantities of purines because nitrogen fixed by bacteria contained within this tissue is transferred to the shoots in the form of ureides, which are degradation products of purines. in animal systems, it has been proposed that proline biosynthesis by pyrroline-5-carboxylate reductase (p5cr) is used to generate the nadp+ required ... | 1988 | 3353366 |
| essential and non-essential domains in the bradyrhizobium japonicum nifa protein: identification of indispensable cysteine residues potentially involved in redox reactivity and/or metal binding. | the amino acid sequence of the bradyrhizobium japonicum nitrogen fixation regulatory protein nifa, as derived from the nucleotide sequence of the nifa gene, was aligned to the corresponding protein sequences from klebsiella pneumoniae, rhizobium meliloti and rhizobium leguminosarum biovar viciae. high conservation was found in the central domain and in the cooh-terminal, putative dna binding domain, whereas very little homology was present within the first 250 amino acids from the nh2-terminus. ... | 1988 | 3357773 |
| structure of the octopine synthase upstream activator sequence. | we have identified a transcriptional activating element within the 5' flanking sequence of the agrobacterium tumefaciens octopine synthase (ocs) gene that is necessary for ocs expression in transformed tobacco calli. this element is located between 333 and 116 base pairs upstream from the transcription initiation site and functions independent of orientation when placed upstream of the ocs gene. it does not function in either orientation when placed downstream of the gene, nor can it activate it ... | 1988 | 3357881 |
| scanning electron microscope studies of agrobacterium tumefaciens attachment to zea mays, gladiolus sp., and triticum aestivum. | scanning electron microscope studies demonstrated that cells of agrobacterium tumefaciens strains attach to cells on the cut surfaces of corn and wheat seedlings and to gladiolus disks. bacterial cells attached to these monocots in the same manner as they attached to the dicots tested. of the strains tested, a66 and t37 covered more of the cut surfaces of these monocots in a nonrandom fashion than did cells of other isolates. these bacteria attached to cells of intact monocotyledonous plants and ... | 1988 | 3360748 |
| cloning and characterization of a gene from rhizobium melilotii 2011 coding for ribosomal protein s1. | a 7 kb chromosomal dna fragment from r. melilotii was cloned, which complemented temperature-sensitivity of an e. coli amber mutant in rpsa, the gene for ribosomal protein s1 (es1). from complementation and maxicell analysis a 58 kd protein was identified as the homolog of protein s1 (rs1). dna sequence analysis of the r. melilotii rpsa gene identified a protein of 568 amino acids, which showed 47% identical amino acid homology to protein s1 from e. coli. the rs1 protein lacked the two cys resid ... | 1988 | 3368316 |
| lectin-enhanced accumulation of manganese-limited rhizobium leguminosarum cells on pea root hair tips. | the ability of rhizobium leguminosarum 248 to attach to developing pisum sativum root hairs was investigated during various phases of bacterial growth in yeast extract-mannitol medium. direct cell counting revealed that growth of the rhizobia transiently stopped three successive times during batch culture in yeast extract-mannitol medium. these interruptions of growth, as well as the simultaneous autoagglutination of the bacteria, appeared to be caused by manganese limitation. rhizobia harvested ... | 1988 | 3384802 |
| chemotaxis of rhizobium meliloti to the plant flavone luteolin requires functional nodulation genes. | luteolin is a phenolic compound from plants that acts as a potent and specific inducer of nodabc gene expression in rhizobium meliloti. we have found that r. meliloti rcr2011 exhibits positive chemotaxis towards luteolin. a maximum chemotactic response was observed at 10(-8) m. two closely related flavonoids, naringenin and apigenin, were not chemoattractants. the presence of naringenin but not apigenin abolished chemotaxis of r. meliloti towards luteolin. a large deletion in the nif-nod region ... | 1988 | 3384804 |
| physiology of behavioral mutants of rhizobium meliloti: evidence for a dual chemotaxis pathway. | wild-type and nonchemotactic mutant strains of rhizobium meliloti were tested for attraction to localized sites on alfalfa roots and for attraction to numerous small molecules, including sugars, amino acids, and two fractions derived from alfalfa root extracts. four strains (carrying mutations che-6, che-11, che-12, and che-26) lost all responses and were classified as generally nonchemotactic mutants. one strain (carrying mutation che-7) lost responses to a group of structurally unrelated amino ... | 1988 | 3384809 |
| vira and virg are the ti-plasmid functions required for chemotaxis of agrobacterium tumefaciens towards acetosyringone. | octopine and nopaline ti-plasmids confer upon agrobacterium tumefaciens c58c1 the ability to respond chemotactically to the vir-inducing phenolic wound exudate, acetosyringone. a. tumefaciens c58c1 containing ti-plasmids with tn5 insertions in virb, c, d or e exhibited marked chemotaxis towards acetosyringone. however, ti-plasmids with mutations in vira or virg were unable to confer the responsive phenotype. of the cosmid clones pvk219 (virab) pvk221 (virbgc) pvk225 (virgcde) and pvk257 (virabgc ... | 1988 | 3398775 |
| a core oligosaccharide component from the lipopolysaccharide of rhizobium trifolii anu843. | the major oligosaccharide from the core region of the lipopolysaccharide from r. trifolii anu843 was isolated and its structure determined. it is a trisaccharide consisting of two galacturonic acid residues and one 3-deoxy-d-manno-2-octulosonic acid (kdo) residue. the two galacturonic acid residues are terminally linked alpha to the c-4 and c-7 atoms of kdo. this structure was determined through use of 1h- and 13c-n.m.r. spectroscopy, f.a.b.-m.s., and g.l.c.-m.s. techniques. this oligosaccharide ... | 1988 | 3401882 |
| amino acid sequences of hemoglobins i and ii from root nodules of the non-leguminous parasponia rigida-rhizobium symbiosis, and a correction of the sequence of hemoglobin i from parasponia andersonii. | the amino acid sequence of hemoglobins i (pi 6.15 as oxyhemoglobin) and ii (pi 5.64 as oxyhemoglobin) from the nitrogen-fixing root nodules of parasponia rigida have been determined by protein sequencing. the sequence of hemoglobin i (pi 6.16, as oxyhemoglobin) from parasponia andersonii was re-examined and the corrected primary structure, now in agreement with that predicted from the dna sequence, is reported. the three parasponia hemoglobins contain 161 amino acid residues (mr approximately eq ... | 1988 | 3402445 |
| characterization of polysaccharides of rhizobium meliloti exo mutants that form ineffective nodules. | mutants of rhizobium meliloti su47 with defects in the production of the calcofluor-binding expolysaccharide succinoglycan failed to gain entry into alfalfa root nodules. in order to define better the polysaccharide phenotypes of these exo mutants, we analyzed the periplasmic oligosaccharide cyclic (1-2)-beta-d-glucan and lipopolysaccharide (lps) in representative mutants. the exoc mutant lacked the glucan and had abnormal lps which appeared to lack a substantial portion of the o side chain. the ... | 1988 | 3403505 |
| association of the vird2 protein with the 5' end of t strands in agrobacterium tumefaciens. | the soil bacterium agrobacterium tumefaciens can incite tumors in many dicotyledonous plants by transferring a portion (t-dna) of its ti plasmid into susceptible plant cells. the t-dna is flanked by border sequences that serve as recognition sites for specific cleavage by an endonuclease that comprises two vird-encoded proteins (vird1 and vird2). after cleavage, both double-stranded, nicked t-dna molecules and single-stranded t-dna molecules (t strands) were present. we have determined that a pr ... | 1988 | 3403506 |
| recognition of individual strains of fast-growing rhizobia by using profiles of membrane proteins and lipopolysaccharides. | membrane protein and lipopolysaccharide profiles of rhizobium leguminosarum (biovars viciae, trifolii, and phaseoli), r. meliloti, and agrobacterium tumefaciens strains were analyzed and compared by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. differences in one or both profiles allowed us to distinguish all 18 r. leguminosarum strains tested in this study from each other. | 1988 | 3403513 |
| induction of nitrogen-fixing nodules on clover requires only 32 kilobase pairs of dna from the rhizobium trifolii symbiosis plasmid. | overlapping subclones from the rhizobium trifolii symbiosis plasmid prt843a were generated by using in vivo and in vitro methods. subclones were assayed for symbiotic phenotype by introducing them into a derivative of r. trifolii anu843 cured of its symbiosis plasmid and testing the transconjugant strains for the ability to induce nitrogen-fixing nodules on clover. one subclone spanning 32 kilobase pairs (kb) of dna from prt843a was found to restore nitrogen fixation ability. this subclone inclu ... | 1988 | 3410817 |
| ti plasmid-specified chemotaxis of agrobacterium tumefaciens c58c1 toward vir-inducing phenolic compounds and soluble factors from monocotyledonous and dicotyledonous plants. | twelve phenolic compounds with related structures were analyzed for their ability to act as chemoattractants for agrobacterium tumefaciens c58c1 and as inducers of the ti plasmid virulence operons. the results divided the phenolic compounds into three groups: compounds that act as strong vir inducers and are chemoattractants for a. tumefaciens c58c1 harboring the nopaline ti plasmid pdub1003 delta 31, but not the isogenic cured strain; compounds that are at best weak vir inducers and are weak ch ... | 1988 | 3410827 |
| detection and subcellular localization of two sym plasmid-dependent proteins of rhizobium leguminosarum biovar viciae. | the previously described sym plasmid-dependent 24-kilodalton rhi protein of rhizobium leguminosarum biovar viciae was localized in the cytosol fraction. another sym plasmid-dependent protein of 50 kilodaltons is secreted into the growth medium, and its expression is dependent on both the nodd gene and a nod gene inducer. | 1988 | 3410833 |
| right-hand border regions of octopine t-dna are recognized by rna polymerase of agrobacterium as well as by vird1 and vird2 proteins. | the t-dna of octopine ti plasmid of agrobacterium tumefaciens contains tl- and tr-dna regions each bounded by 25 base-pair-repeats (designated a, b, c and d from left to right). short dna segments containing the borders b, c and d were found to function as promoter when placed in the rightward orientation upstream of promoter-less lacz. promoter consensus sequence of agrobacterium were found within these border repeats and in their adjacent regions. the expression of lacz was low when the segmen ... | 1988 | 3412897 |
| a large family of bacterial activator proteins. | at least nine different bacterial proteins belong to the lysr family. the gene sequence for one of these proteins is presented here. six others (escherichia coli lysr, ilvy, cysb; salmonella typhimurium metr; rhizobium nodd; and enterobacter cloacae ampr) are known to activate other genes. based on sequence alignments, each member of this family is predicted to have a helix-turn-helix dna binding motif near its amino terminus. the combined evidence indicates that all nine proteins are related by ... | 1988 | 3413113 |
| expression of nodule-specific genes in alfalfa root nodules blocked at an early stage of development. | to help dissect the molecular basis of the rhizobium-legume symbiosis, we used in vitro translation and northern blot analysis of nodule rna to examine alfalfa-specific genes (nodulins) expressed in two types of developmentally defective root nodules elicited by rhizobium meliloti. fix- nodules were elicited by r. meliloti nif mutants; these nodules were invaded by rhizobia and contained differentiated bacteroids. 'empty' nodules were elicited by r. meliloti exo and ndv mutants and by agrobacter ... | 1988 | 3417147 |
| identification of nodx, a gene that allows rhizobium leguminosarum biovar viciae strain tom to nodulate afghanistan peas. | gene(s) conferring the ability of rhizobium leguminosarum biovar viciae strain tom to nodulate primitive peas (cultivar afghanistan) had been located in a 2.0 kb region of its sym plasmid, prl5ji. in this dna, a single open reading frame of 1101 bp, corresponding to a gene, nodx was found. nodx is downstream of nodj which is present in strain tom and also in the sym plasmid of a typical strain of this biovar. nodx specifies a hydrophobic protein (of mr 41,036) with no clear similarity to other p ... | 1988 | 3419422 |
| vir box sequences in agrobacterium tumefaciens ptic58 and a6. | 1988 | 3419938 | |
| dicarboxylic acid transport in bradyrhizobium japonicum: use of rhizobium meliloti dct gene(s) to enhance nitrogen fixation. | a recombinant plasmid encoding rhizobium meliloti sequences involved in dicarboxylic acid transport (plasmid prk290:4:46) (e. bolton, b. higgisson, a. harrington, and f. o'gara, arch. microbiol. 144:142-146, 1986) was used to study the relationship between dicarboxylic acid transport and nitrogen fixation in bradyrhizobium japonicum. the expression of the dct sequences on plasmid prk290:4:46 in b. japonicum cj1 resulted in increased growth rates in media containing dicarboxylic acids as the sole ... | 1988 | 3422072 |
| seed-transmissible expression of mammalian metallothionein in transgenic tobacco. | a binary plasmid was constructed to contain the mouse metallothionein c-dna, the constitutive 35s promoter from cauliflower mosaic virus, the polyadenylation signal from the pea rbcs-e9 gene and several selectable markers. the plasmid was transferred to agrobacterium tumefaciens and the leaf disc method was used to transform tobacco. callus and shoots were regenerated in the presence of kanamycin and transformed plants were obtained. southern, northern and western blot analysis demonstrated inte ... | 1988 | 2829879 |
| mapping of agrobacterium tumefaciens chromosomal genes affecting cellulose synthesis and bacterial attachment to host cells. | six chromosomal transposon mutations in agrobacterium tumefaciens which result in an inability to synthesize cellulose fibrils were mapped to the vicinity of trp-2 and met-6. mutations which result in an inability to attach to plant cells, attc43 and attc69, also mapped in this region, as did one tn5 mutation which caused overproduction of cellulose. another cellulose overproduction mutation mapped at a distance and was closely linked to ilv-13. the results suggest that there is a region of the ... | 1988 | 2830241 |
| transcription of a rhizobium leguminosarum biovar phaseoli gene needed for melanin synthesis is activated by nifa of rhizobium and klebsiella pneumoniae. | the rhizobium leguminosarum biovar phaseoli symbiotic plasmid prp2ji carries a gene, mela, specifying the enzyme tyrosinase, which is responsible for the production of the pigment melanin in these bacteria. transcription of mela is activated by the nifa gene of rhizobium and, when the cloned mela gene is transferred to escherichia coli, mela is expressed if the recipients contain nifa gene of klebsiella pneumoniae. this nifa-dependent activation was temperature sensitive and required the ntra ge ... | 1988 | 3041240 |
| the ndva gene product of rhizobium meliloti is required for beta-(1----2)glucan production and has homology to the atp-binding export protein hlyb. | the ndva locus of rhizobium meliloti is homologous to and can substitute for the chva locus of agrobacterium tumefaciens. we have previously shown that an ndva mutant exhibited reduced motility and formed small, white, empty nodules on alfalfa roots. here we show that this ndva mutant is defective in the production of the cyclic extracellular polysaccharide beta-(1----2)glucan, even though a 235,000-dalton protein intermediate, known to be involved in the synthesis of this molecule, is present a ... | 1988 | 3042754 |
| transfer of the ti plasmid from agrobacterium tumefaciens into escherichia coli cells. | we have screened strains of agrobacterium tumefaciens for spontaneous mutants showing constitutive transfer of the nopaline ti plasmid ptic58 during conjugation. the ti plasmid derivatives obtained could be transferred not only to a. tumefaciens but also to e. coli cells. the ti plasmid cannot survive as a freely replicating plasmid in e. coli, but it can occasionally integrate into the e. coli chromosome. however, insertion in tandem of plasmids carrying fd replication origins (pfd plasmids) in ... | 1988 | 3049936 |
| flavonoids in the environment: structure-activity relationships. | 1988 | 3051025 | |
| conformational changes in the membrane-bound hydrogenase of bradyrhizobium japonicum. evidence that the redox state of the enzyme affects its accessibility to protease and membrane-impermeant reagents. | the sensitivity of the membrane-bound hydrogenase of bradyrhizobium japonicum to inactivation by proteases and membrane-impermeant protein modification reagents was compared under hydrogen versus oxygen. in membrane vesicles, the half-life of enzyme inactivation by trypsin of the h2-reduced enzyme was approximately 10 min, whereas o2-oxidized enzyme was much less sensitive to trypsin inactivation (half-life of over 90 min). diazobenzene sulfonate (dabs) affected the enzyme activity in a manner s ... | 1988 | 3053719 |
| further analysis of nitrogen fixation (nif) genes in azotobacter chroococcum: identification and expression in klebsiella pneumoniae of nifs, nifv, nifm, and nifb genes and localization of nife/n-, nifu-, nifa- and fixabc-like genes. | the results presented extend previous investigations on the genetics of nitrogen fixation in azotobacter chroococcum and indicate that nif- and fix-like dna is located in at least five different regions of the genome. region i contains functional copies of nifs,v and m, as well as nifh, d and k, all of which complemented mutants of klebsiella pneumoniae. in addition, nife- and/or nifn-like and nifu-like dna is located in this region. the organization of the nif cluster in region i closely resemb ... | 1988 | 3053983 |
| rhizobium meliloti host range nodh gene determines production of an alfalfa-specific extracellular signal. | the rhizobium meliloti nodh gene is involved in determining host range specificity. by comparison with the wild-type strain, nodh mutants exhibit a change in host specificity. that is, although nodh mutants lose the ability to elicit root hair curling (hac-), infection threads (inf-), and nodule meristem formation (nod-) on the homologous host alfalfa, they gain the ability to be hac+ inf+ nod+ on a nonhomologous host such as common vetch. using root hair deformation (had) bioassays on alfalfa a ... | 1988 | 3056902 |
| high-frequency transformation of rhizobium meliloti. | transformation of r factor rp4 and its derivative prk290 from escherichia coli to rhizobium meliloti is reported. the efficiency of transformation was in the range of 10(-5) per viable cell. in addition, chromosomal dna prepared from one r. meliloti strain resistant to streptomycin was transferred to the isoleucine-valine-requiring mutant susceptible to streptomycin. | 1988 | 3056925 |
| bidirectional transfer from a 24 bp border repeat of agrobacterium tumefaciens. | t-region transfer from wild-type agrobacterium strains is thought to be an orientated process, starting at the right border repeat and terminating at the left border repeat of the t-region. here we demonstrate that a right border repeat in the inverted orientation relative to the onc-genes can also mediate transfer of the t-region to the plant cell, although with lower efficiency as a border repeat in the native orientation. transfer mediated by an inverted right border repeat is stimulated by t ... | 1988 | 3057440 |
| effect of agrobacterium tumefaciens lipopolysaccharide on hemolytic complement system. | 1988 | 3058583 | |
| factors affecting the survival and growth of bacteria introduced into lake water. | the populations of pseudomonas sp. b4, escherichia coli, klebsiella pneumoniae, micrococcus flavus, and rhizobium leguminosarum biovar phaseoli declined rapidly in lake water. the initially rapid decline of the two pseudomonads and r. phaseoli was followed by a period of slow loss of viability, but viable cells of the other species were not found after 10 days. the rapid initial phase of decline was not a result of bdellovibrio spp., bacteriophages, or toxins in the water since bdellovibrio spp. ... | 1988 | 3060035 |
| cosmids. | 1988 | 3061512 | |
| the dna-binding domain of the transcriptional activator protein nifa resides in its carboxy terminus, recognises the upstream activator sequences of nif promoters and can be separated from the positive control function of nifa. | the positive control protein nifa activates transcription of nitrogen fixation promoters in klebsiella pneumoniae. nifa is believed to bind to specific sites, the upstream activator sequences (uas's), of the nif promoters which it activates. we have now shown by mutation of the carboxy terminus of nifa that this is the dna-binding domain and that the dna-binding and positive activator functions of nifa can be separated. mutational analysis of the nifh uas and in vivo methylation protection analy ... | 1988 | 3062575 |
| detection of ligand-protein binding by direct electrophoresis of the complex. | 1988 | 3069855 | |
| basic processes underlying agrobacterium-mediated dna transfer to plant cells. | 1988 | 3071244 | |
| foreign genes in plants: transfer, structure, expression, and applications. | 1988 | 3071255 | |
| nickel as a micronutrient element for plants. | the detrimental effects of excessive ni on plant growth have been well known for many years. more recent evidence indicates that ni is required in small amounts for normal plant growth and development. ni is an essential component of urease in plants and microorganisms. a deficiency of ni in plants is reported to result in necrotic lesions in leaves in response to toxic accumulations of urea. urease plays an essential role in mobilization of nitrogenous compounds in plants, a process that is esp ... | 1988 | 3076427 |
| flavones and isoflavones as inducing substances of legume nodulation. | rhizobia are soil bacteria that can form symbiotic associations with leguminous plants leading to the fixation of atmospheric nitrogen to ammonia which the plant can use. this is an interaction which involves the exchange of many signals between the plant and the bacterium. to start this interaction, rhizobia have adapted to use flavonoid compounds, released by the plant root, as part of a regulatory system to initiate the transcription of their infection (nodulation, nod) genes. the development ... | 1988 | 3076431 |
| development and differentiation of the root nodule. involvement of plant and bacterial genes. | 1988 | 3077981 | |
| characterization of the rhizobium leguminosarum genes nodlmn involved in efficient host-specific nodulation. | three nodulation genes, nodl, nodm and nodn, were isolated from rhizobium leguminosarum and their dna sequences were determined. the three genes are in the same orientation as the previously described nodfe genes and the predicted molecular weights of their products are 20,105 (nodl), 65,795 (nodm) and 18,031 (nodn). analysis of gene regulation using operon fusions showed that nodl, nodm and nodn are induced in response to flavanone molecules and that this induction is nodd-dependent. in additio ... | 1988 | 3132583 |
| hydrogen metabolism in rhizobium: energetics, regulation, enzymology and genetics. | 1988 | 3132815 | |
| escherichia coli lacz gene as a biochemical and histochemical marker in plant cells. | several lacz chimeric genes were constructed by fusing the truncated lacz sequence of escherichia coli to n-terminal sequences of few other genes. promoters used to direct expression of the chimeric genes were the promoter for 35s rna of cauliflower mosaic virus (p35s) as well as those of the small subunit gene of ribulose bisphosphate carboxylase and the octopine synthase gene. these constructs were introduced into tobacco cells using a ti plasmid of agrobacterium tumefaciens, and beta-galactos ... | 1988 | 3138164 |
| differentiation of some gram-negative glucose nonfermenting bacteria using miniaturized carbon sources assimilation tests. | in water and soil the gram-negative nonfermenting bacteria play an important role in the biological mineralization process. to improve the methods for species differentiation of these heterogenous bacterial group, a total of 481 reference strains of gram-negative glucose nonfermenting bacteria belonging to the genera pseudomonas, alcaligenes, bordetella, agrobacterium, moraxella, acinetobacter, flavobacterium and some cdc groups have been investigated for their ability to utilize 42 different ca ... | 1988 | 3142164 |
| role of sublethal injury in decline of bacterial populations in lake water. | following their addition to lake water, the populations of escherichia coli and of antibiotic-resistant strains of pseudomonas fluorescens, agrobacterium tumefaciens, micrococcus flavus, rhizobium meliloti, and klebsiella pneumoniae declined rapidly, as determined by counting on media containing antibacterial compounds. the estimates of population sizes were occasionally higher if procedures were used that permitted possible resuscitation of injured cells. no resuscitation procedure yielded cons ... | 1988 | 3145714 |
| cloning and characterization of a novel beta-galactosidase-coding gene from rhizobium meliloti. | the rhizobium meliloti (rm) lacz gene provides a convenient model to investigate patterns of gene regulation in these agronomically important bacteria. a gene encoding beta-galactosidase (beta gal) activity was cloned from r. meliloti by complementing a lactose-negative escherichia coli mutant. a series of sau3a subclones was generated in pbr322, and the coding region for the beta gal-coding gene was localized to a 2.4-kb core fragment. in e. coli 'maxicells', these lacz subclones produced a 79- ... | 1988 | 3145908 |
| evidence for a role of a vicinal dithiol in the transport of gamma-butyrobetaine in agrobacterium sp. | an agrobacterium sp. isolated from soil is able to use gamma-butyrobetaine as its sole source of carbon and nitrogen. the involvement of thiol groups for active transport of gamma-butyrobetaine was investigated by use of the thiol alkylating reagent n-ethylmaleimide (nem) and the dithiol specific reagent phenylarsine oxide (pao). both reagents strongly inhibited gamma-butyrobetaine uptake, but also induced the release of the accumulated substrate, suggesting that the transport system either cont ... | 1988 | 3148329 |
| identification of cytoplasmic nodule-associated forms of malate dehydrogenase involved in the symbiosis between rhizobium leguminosarum and pisum sativum. | the malate dehydrogenase activity (ec 1.1.1.37), present in the cytoplasm of pisum sativum root nodules, can be separated by ion-exchange chromatography into four different fractions. malate dehydrogenase activity present in the cytoplasm of roots elutes mainly as a single peak. during nodule development an increase in malate dehydrogenase activity per gram of material was observed. this increase occurred concomitantly with the increase in nitrogenase activity. the kinetic properties of the sepa ... | 1988 | 3162212 |
| relative strengths of the 35s cauliflower mosaic virus, 1', 2', and nopaline synthase promoters in transformed tobacco sugarbeet and oilseed rape callus tissue. | the 35s promoter of cauliflower mosaic virus and promoters from the nopaline synthase, 1' and 2' genes of agrobacterium tumefaciens t-dna were fused to the bacterial octopine synthase and chitinase gene coding regions. these chimaeric gene constructions were introduced into tobacco, sugarbeet and oilseed rape cells and their relative levels of expression measured by primer extension analysis of rna isolated from pooled populations of stably transformed calli. in tobacco callus, the 35s promoter ... | 1988 | 3163765 |
| expression of tandem gene fusions in transgenic tobacco plants. | we have studied the expression of four sets of tandem gene fusions in transgenic tobacco plants. this was to determine if the problem of between-transformant variability in expression of introduced genes could be overcome by using a linked reference gene as a co-ordinately expressed control. tandem gene fusions containing identical 5' flanking regions (ssu301-ocs with either ssu301-cat or ssu301-ssu911) were not co-ordinately expressed in the transgenic tobacco plants whereas the tandem gene fus ... | 1988 | 3166132 |
| rola locus of the ri plasmid directs developmental abnormalities in transgenic tobacco plants. | plants containing the left t-dna (tl) of agrobacterium rhizogenes show a variety of developmental abnormalities that include severely wrinkled leaves, loss of apical dominance, reduced geotropism of roots, reduced internode distances, and floral hyperstyly. the tl-dna also affects the morphology of tumor tissue at the site of inoculation on kalanchoe diagremontiana leaves. single mutations at four loci of the tl-dna (rola, rolb, rolc, and rold) are known to affect tumor morphology on k. diagremo ... | 1988 | 3166443 |
| phosphoglycerol substituents present on the cyclic beta-1,2-glucans of rhizobium meliloti 1021 are derived from phosphatidylglycerol. | the synthesis of periplasmic cyclic beta-1,2-glucans is a property unique to species of the family rhizobiaceae. for this reason, it is generally believed that these molecules may play an important role in the plant infection process. in the present study, we determined that the cyclic beta-1,2-glucans produced by rhizobium meliloti 1021 were predominantly anionic in character and contained both phosphoglycerol and succinic acid substituents. in addition, we demonstrated that phosphatidylglycero ... | 1988 | 3170478 |
| flavonoids in the rhizobium-legume symbiosis. | 1988 | 3174708 | |
| isolation and characterization of root nodule proteins from lupin. | a group of root nodule-specific plant proteins (nodulins) has been isolated from yellow lupin (lupinus luteus) by immunoaffinity chromatography. the cytoplasmic nodule protein extract was initially enriched in nodulins on a column with immobilized igg fraction. it was then purified by chromatography on sepharose 4b - bound igg against uninfected root proteins and finally on sepharose 4b - bound igg against rhizobium lupini proteins. rocket immunoelectrophoresis showed that the nodulin preparatio ... | 1988 | 3176786 |
| deoxyribonuclease i sensitivity of the t-dna ipt gene is associated with gene expression. | we have analyzed the chromatin structure of the t-dna isopentenyl transferase gene, ipt, in four nicotiana tabacum crown gall tumor lines. these four transformed lines contain identical t-dna inserts and are derivatives of a single clone that did not exhibit any tumorous properties and contained a highly methylated, nonexpressed copy of t-dna. one of the derivatives also does not exhibit tumorous properties, and the t-dna of this line is not expressed. the other three lines have reverted to tumo ... | 1988 | 3179274 |
| role of iron in the enhancement by agrobacterium tumefaciens infection in mice. | microorganisms require iron for their growth and usually compete with their host for available iron from the system. iron supplementation to host causes an increase of available iron both to host and to potential microbial invaders and favours the latter more than the former as the bacteria release siderophores which are responsible for iron transport mechanism. in view of this observation a study was done to deal with the distribution of storage and injected iron given as an overload within a p ... | 1988 | 3181831 |
| purification and properties of the gamma-butyrobetaine-binding protein from an agrobacterium sp. | a binding protein for gamma-butyrobetaine was purified from osmotic shock fluid of an agrobacterium sp. it was a monomeric protein with an apparent molecular weight of 52,000 or 53,000 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel filtration, respectively. the isoelectric point was 4.3, as determined by isoelectric focusing. amino acid analysis of the protein showed that asx and glx were predominant components and that the protein contained no cysteine. the d ... | 1988 | 3182728 |
| isolation and characterization of azospirillum brasilense loci that correct rhizobium meliloti exob and exoc mutations. | the occurrence in azospirillum brasilense of genes that code for exopolysaccharide (eps) synthesis was investigated through complementation studies of rhizobium meliloti exo- mutants. these mutants are deficient in the synthesis of the major acidic eps of rhizobium species and form empty, non-nitrogen-fixing root nodules on alfalfa (j. a. leigh, e. r. signer, and g. c. walker, proc. natl. acad. sci. usa 82:6231-6235, 1985). we demonstrated that the exoc mutation of r. meliloti could be corrected ... | 1988 | 3182731 |
| symbiotic phenotypes of auxotrophic mutants of rhizobium meliloti 104a14. | auxotrophic mutants of rhizobium meliloti 104a14 were isolated using nitrous acid mutagenesis followed by penicillin enrichment. mutants in ornithine transcarbamylase, argininosuccinate synthetase or serine-glycine biosynthesis formed nitrogen-fixing (fix-nodules on the roost of alfalfa (medicago sativa). mutants with defects in ornithine, pyrimidine, purine, asparagine, leucine, methionine or tyrosine biosynthesis, in one-carbon metabolism or in carbamoylphosphate synthetase formed nodules but ... | 1988 | 3183624 |
| organization and characterization of the vircd genes from agrobacterium rhizogenes. | we have precisely localized virulent (vir) genes of the hairy root-inducing plasmid pria4b on the basis of sequence similarity with the tumor-inducing plasmid ptia6nc, and shown that the overall organizations of vir genes in both plasmids are fairly analogous, although sizes and spacer lengths in some genes differ from each other. among the vir genes thus mapped, the virc and vird loci were characterized in detail. transposon insertions in vird led to loss of tumorigenicity on kalanchoe stems an ... | 1988 | 3185501 |
| conservation of nif sequences in frankia. | southern blots of frankia total dnas were hybridized with nifhdk probes from rhizobium meliloti, klebsiella pneumoniae and frankia strain arl3. differences between strains were noted in the size of the hybridizing restriction fragments. these differences were more pronounced among elaeagnus-compatible strains than among alnus- or casuarina-compatible strains. gene banks constructed for frankia strains eun1f, hrn18a, ced and acon24d were used to isolate nif-hybridizing restriction fragments for s ... | 1988 | 3185502 |