| cloning of rhizobium leguminosarum genes for competitive nodulation blocking on peas. | one type of competitive interaction among rhizobia is that between nonnodulating and nodulating strains of rhizobium leguminosarum on primitive pea genotypes. pisum sativum cv. afghanistan nodulates effectively with r. leguminosarum tom, and this can be blocked in mixed inoculations by r. leguminosarum pf2, which does not nodulate this cultivar. we termed this pf2 phenotype cnb+, for competitive nodulation blocking. strain pf2 contains three large plasmids including a 250-kilobase-pair symbiotic ... | 1987 | 3546272 |
| characterization of the vire operon of the agrobacterium ti plasmid ptia6. | the agrobacterium tumefaciens ti plasmid contains at least six transcriptional units (designated vir loci) which are essential for efficient crown gall tumorigenesis. mutations in one of these loci, vire, result in a sharply attenuated virulence phenotype. in the present communication, we have analyzed the vire operon at the molecular level. this locus contains open reading frames coding for two hydrophilic proteins having molecular weights of approximately 7,000 daltons and 60,500 daltons. usin ... | 1987 | 3547330 |
| characterization of the vire locus of agrobacterium tumefaciens plasmid ptic58. | the vire locus that is responsible for the efficiency of infection by agrobacterium tumefaciens (t. hirooka and c. kado, j. bacteriol. 168:237-243, 1986) is located next to the right boundary of the virulence (vir) region of the nopaline plasmid ptic58. this locus is very similar to the vire locus of octopine type ti plasmids on the basis of nucleotide and amino acid sequence comparisons as well as genetic complementation analyses. the nucleotide sequence of vire revealed three open reading fram ... | 1987 | 3549694 |
| [hybridization of dna from actinomycetes of the genus frankia with nitrogenase structural genes (nifhdk) of klebsiella pneumoniae and nod-genes of rhizobium melioti]. | dna sequence homology with the plasmid psa30 carrying the cloned nifhdk genes from klebsiella pneumoniae was revealed in ten frankia spp. strains, nitrogen-fixing symbionts of non-legumes, irrespective of the strain phenotype (nod+fix+, nod+ fix- or nod- fix?). none of the frankia spp. dnas exhibited homology with the plasmid prmsl26 harbouring the rhizobium meliloti nod-genes encoding for early symbiotic functions. | 1987 | 3553912 |
| agrobacterium tumefaciens-mediated transformation of the monocot genus gladiolus: detection of expression of t-dna-encoded genes. | agrobacterium tumefaciens was capable of directing the transformation of gladiolus sp., a monocot genus belonging to the family iridaceae. only strains capable of transferring t-dna formed tumors, sections of which could be cultured in phytohormone-free media. opine synthase activities were also observed in homogenates made from these tumors. | 1987 | 3558323 |
| a gene upstream of the rhizobium trifolii nifa gene encodes a ferredoxin-like protein. | | 1987 | 3562251 |
| common loci for agrobacterium tumefaciens and rhizobium meliloti exopolysaccharide synthesis and their roles in plant interactions. | mutants of rhizobium meliloti have been isolated which are deficient in exopolysaccharide (eps) production and effective nodulation of alfalfa (j. a. leigh, e. r. signer, and g. c. walker, proc. natl. acad. sci. usa 82:6231-6235, 1985). we isolated approximately 100 analogous eps-deficient (exo) mutants of the closely related plant pathogen agrobacterium tumefaciens, including strains whose eps deficiencies were specifically complemented by each of five cloned r. meliloti exo loci. we also clone ... | 1987 | 3571162 |
| a new symbiotic cluster on the psym megaplasmid of rhizobium meliloti 2011 carries a functional fix gene repeat and a nod locus. | a 290-kilobase (kb) region of the rhizobium meliloti 2011 psym megaplasmid, which contains nodulation genes (nod) as well as genes involved in nitrogen fixation (nif and fix), was shown to carry at least six sequences repeated elsewhere in the genome. one of these reiterated sequences, about 5 kb in size, had previously been identified as part of a cluster of fix genes located 220 kb downstream of the nifhdk promoter. deletion of the reiterated part of this fix cluster does not alter the symbiot ... | 1987 | 3571166 |
| molecular characterization of the virc genes of the ti plasmid. | the virc (formerly bak) complementation group of the nopaline-type ti plasmid ptic58 encodes two proteins, virc1 and virc2. according to the primary structure of the polypeptides predicted by the nucleotide sequence, virc1 is composed of 231 amino acids with a total molecular mass of 25.5 kilodaltons, and virc2 is composed of 202 amino acids with a molecular mass of 22.1 kilodaltons. the ptic58 virc1 and virc2 polypeptides are equal in length to virc1 and virc2 of the octopine-type plasmid ptia6 ... | 1987 | 3584058 |
| a locus encoding host range is linked to the common nodulation genes of bradyrhizobium japonicum. | by using cloned rhizobium meliloti, rhizobium leguminosarum, and rhizobium sp. strain mpik3030 nodulation (nod) genes as hybridization probes, homologous regions were detected in the slow-growing soybean symbiont bradyrhizobium japonicum usda 110. these regions were found to cluster within a 25-kilobase (kb) region. specific nod probes from r. meliloti were used to identify noda-, nodb-, nodc-, and nodd-like sequences clustered on two adjacent hindiii restriction fragments of 3.9 and 5.6 kb. a 7 ... | 1987 | 3584066 |
| nitrogen-fixing nodules induced by agrobacterium tumefaciens harboring rhizobium phaseoli plasmids. | rhizobium phaseoli cfn299 forms nitrogen-fixing nodules in phaseolus vulgaris (bean) and in leucaena esculenta. it has three plasmids of 185, 225, and 410 kilobases. the 410-kilobase plasmid contains the nitrogenase structural genes. we have transferred these plasmids to the plasmid-free strain agrobacterium tumefaciens gmi9023. transconjugants containing different combinations of the r. phaseoli plasmids were obtained, and they were exhaustively purified before nodulation was assayed. only tran ... | 1987 | 3584072 |
| agrobacterium tumefaciens ptar para promoter region involved in autoregulation, incompatibility and plasmid partitioning. | the locus responsible for directing proper plasmid partitioning of agrobacterium tumefaciens ptar is contained within a 1259 base-pair region. insertions or deletions within this locus can result in the loss of the plasmid's ability to partition properly. one protein product (para), approximately 25,000 mr, is expressed from the par locus in escherichia coli and a. tumefaciens protein analysis systems in vitro. dna sequence analysis of the locus revealed a single 23,500 mr open reading frame, co ... | 1987 | 3586028 |
| characterization of the vira locus of agrobacterium tumefaciens: a transcriptional regulator and host range determinant. | the virulence (vir) region of agrobacterium tumefaciens mediates the transfer of a defined segment of plasmid dna (the t-dna) into the plant genome. the vir genes are specifically induced by molecules produced by wounded plant cells, and vira is required for this induction. we have determined the nucleotide sequence of vira loci from limited (ptiag162) and wide (ptia6) host range tumor-inducing (ti) plasmids, each of which encodes a single protein of 92,000 daltons. using antibody directed again ... | 1987 | 3595559 |
| activation of agrobacterium tumefaciens vir gene expression generates multiple single-stranded t-strand molecules from the ptia6 t-region: requirement for 5' vird gene products. | agrobacterium tumefaciens transfers its ti-plasmid t-dna to plant cells. this process is initiated by plant-induced activation of the ti-plasmid virulence loci, resulting in the generation of single stranded (ss) cleavages of the ti-plasmid t-dna border sequences (border nicks) and ss linear unipolar t-dna molecules (t-strands). a single t-strand is produced from the two-border t-region of the pgv3850 nopaline plasmid. in this paper the induced molecular events for the complex t-region of the pt ... | 1987 | 3595560 |
| expression of rhizobium meliloti nod genes in rhizobium and agrobacterium backgrounds. | rhizobium meliloti nod genes are required for the infection of alfalfa. induction of the nodc gene depends on a chemical signal from alfalfa and on nodd gene expression. by using a nodc-lacz fusion, we have shown that the induction of the r. meliloti nodc gene and the expression of nodd occur at almost normal levels in other rhizobium backgrounds and in agrobacterium tumefaciens, but not in escherichia coli. xanthomonas campestris, or pseudomonas savastanoi. our results suggest that bacterial ge ... | 1987 | 3597319 |
| rhizobium meliloti swims by unidirectional, intermittent rotation of right-handed flagellar helices. | the 5 to 10 peritrichously inserted complex flagella of rhizobium meliloti mvii-1 were found to form right-handed flagellar bundles. bacteria swam at speeds up to 60 microns/s, their random three-dimensional walk consisting of straight runs and quick directional changes (turns) without the vigorous angular motion (tumbling) seen in swimming escherichia coli cells. observations of r. meliloti cells tethered by a single flagellar filament revealed that flagellar rotation was exclusively clockwise, ... | 1987 | 3597320 |
| identification of a new virulence locus in agrobacterium tumefaciens that affects polysaccharide composition and plant cell attachment. | we have identified a new virulence locus in agrobacterium tumefaciens. strains carrying tn5 inserts at this locus could not incite tumors on kalanchoe daigremontiana, nicotiana rustica, tobacco, or sunflower and had severely attenuated virulence on carrot disks. we termed the locus psca, because the mutants that defined the locus were initially isolated as having an altered polysaccharide composition; they were nonfluorescent on media containing leucophor or calcofluor, indicating a defect in th ... | 1987 | 3597321 |
| reexamination of the presence and linkage of 3-hydroxybutyryl substituents in the acidic capsular polysaccharide of rhizobium trifolii 0403. | we resolved previous conflicting results concerning the presence of 3-hydroxybutyryl substituents on the extracellular acidic polysaccharide from rhizobium trifolii 0403. these substituents were indeed present in the polysaccharide and in the oligosaccharide fragments obtained by hydrogen fluoride solvolysis of the extracellular and capsular polysaccharides of the bacteria grown on plates. the 3-hydroxybutyrate substituent could be removed from the polysaccharide by 10 mm sodium deuteroxide with ... | 1987 | 3597324 |
| flavonoids induce rhizobium leguminosarum to produce noddabc gene-related factors that cause thick, short roots and root hair responses on common vetch. | rhizobium leguminosarum produced a factor(s) that caused thick, short roots (tsr phenotype) as well as root hair induction (hai phenotype) and deformation (had phenotype) in vicia sativa plants upon incubation with root exudate or with one of the nod gene inducers naringenin or apigenin; this was a noddabc gene-dependent process. detection of the hai and had phenotypes was much more sensitive than that of the tsr phenotype. | 1987 | 3597326 |
| cloning and identification of lupin nodule specific cdna sequences. | yellow lupin nodule specific sequences were selected by screening of cdna library prepared from lupin nodule poly(a)+rna. from about 3,000 clones containing fragments of lupin dna 150-1,500 base pair long, 7% of clones carrying nodule specific sequences were identified. among them the most abundant sequence species, represented by 32% clones, encodes leghemoglobin. another abundant species designated pln13 is represented by 13% clones. the northern blot analysis of lupin mrna confirmed nodule sp ... | 1987 | 3604516 |
| characterization of agrobacterium tumefaciens strains isolated from grapevine tumors in china. | thirteen strains of agrobacterium tumefaciens isolated from grapevine tumors in northern china were surveyed. these strains varied in their host range properties, although all were tumorigenic on grapevines. twelve of these strains belonged to agrobacterium sp. biotype 3, and 11 strains resulted in the synthesis of the opine octopine in tumor tissue. interestingly, one strain resulted in accumulation of arginine, a previously unrecognized opine, in tumor tissue. although dna in most of these str ... | 1987 | 3606110 |
| promoter cassettes, antibiotic-resistance genes, and vectors for plant transformation. | we have constructed a set of plant transformation vectors, promoter cassettes, and chimeric antibiotic-resistance genes for the transformation and expression of foreign genes in plants sensitive to agrobacterium infection. the different vectors allow for either concurrent or consecutive selection for kanamycin and hygromycin resistance and have a number of unique restriction sites for the insertion of additional dna. the promoter cassettes utilize the camv 19s and camv 35s promoters and are cons ... | 1987 | 3609746 |
| structure of the bradyrhizobium japonicum gene hema encoding 5-aminolevulinic acid synthase. | the nucleotide (nt) sequence of the hema gene, which encodes 5-aminolevulinic acid synthase (alas) from the bacterium bradyrhizobium japonicum, is presented. this sequence predicts a protein of 408 amino acids (aa) with an mr of 44,599. this predicted amino acid sequence is highly homologous to that of the chicken embryonic liver alas, exhibiting a 48.8% identical amino acid sequence over the entire length of the bacterial protein. a single mrna start point was demonstrated by s1 protection anal ... | 1987 | 3609750 |
| structure of a polysaccharide containing galactose and galacturonic acid from rhizobium meliloti. characterization and partial purification of a 2-o-methyltransferase. | the teichuronic acid type polysaccharide found in rhizobium meliloti which is associated with sensitivity to phage 16b and is formed in the inner membranes from udp-galactose and udp-galacturonic acid (ugalde, r. a., coira, j. a., and brill, w. j. (1986) j. bacteriol. 168, 270-275) has been studied further. results of acid hydrolysis, periodate oxidation, and borohydride reduction show that this polysaccharide contains the repetitive unit -galacturonosyl(1-3)galactosyl(1-4-). a soluble enzyme wa ... | 1987 | 3611083 |
| homology studies demonstrate colinear organization of the transferred regions of plasmids pri 1855 and pri 8196 from agrobacterium rhizogenes. | agrobacterium rhizogenes, a pathogenic bacterium determining for hairy-root tumors in plants, acts by insertion of a fragment (t-dna) of its ri plasmid into the plant nuclear dna. two a. rhizogenes strains, pri 1855 and pri 8196, responsible for similar disease symptoms, differ when compared at the structural level. however, some morphogenetic loci previously identified by insertion mutagenesis in either one of the two t-dnas seem physiologically equivalent. the possibility that these morphogene ... | 1987 | 3615659 |
| [profiles of enzymatic activities of the genera agrobacterium, alcaligenes, alteromonas, flavobacterium and pseudomonas]. | profiles of enzymatic activities were studied using 19 chromogenic substrates for 22 species (211 strains) belonging to the genera agrobacterium, alcaligenes, alteromonas, flavobacterium and pseudomonas. the observed patterns of reactions may be useful as an aid in identification of these species and for epidemiological studies. | 1987 | 3620200 |
| a new vector derived from agrobacterium rhizogenes plasmids: a micro-ri plasmid and its use to construct a mini-ri plasmid. | a new binary vector system has been constructed, based on agropine-type root-inducing plasmid (pri) left transferred-region border sequences cloned in a plasmid containing the replication origin of another a. rhizogenes plasmid (para4a). this micro-pri has been used to introduce a chimeric kanamycin resistance gene into tobacco plants, vir functions being provided by either octopine or nopaline tumor-inducing plasmids deleted of their own transferred regions. in addition, we show that cloning of ... | 1987 | 3623102 |
| cytokinin production by agrobacterium and pseudomonas spp. | the production of cytokinins by plant-associated bacteria was examined by radioimmunoassay. strains producing trans-zeatin were identified in the genera agrobacterium and pseudomonas. agrobacterium tumefaciens strains containing nopaline tumor-inducing plasmids, a. tumefaciens lippia isolates, and agrobacterium rhizogenes strains produced trans-zeatin in culture at 0.5 to 44 micrograms/liter. pseudomonas solanacearum and pseudomonas syringae pv. savastanoi produced trans-zeatin at levels of up t ... | 1987 | 3624204 |
| involvement of both cellulose fibrils and a ca2+-dependent adhesin in the attachment of rhizobium leguminosarum to pea root hair tips. | we have previously described an assay for the attachment of rhizobium bacteria to pea root hair tips (cap formation) which was used as a model to study the attachment step in the nodulation process. under all conditions tested, a positive correlation was observed between the percentage of fibrillated cells and the ability of these bacteria to form caps and to adhere to glass, suggesting that fibrils play a role in the attachment of rhizobium leguminosarum to pea root hair tips and to glass (g. s ... | 1987 | 3624205 |
| a. tumefaciens pti a6 and c58 vir c and d promoter alignment. | | 1987 | 3628008 |
| three-dimensional structure of the complex flagellar filament of rhizobium lupini and its relation to the structure of the plain filament. | electron micrographs of negatively stained preparations were used to obtain a three-dimensional reconstruction of the complex flagellar filament of rhizobium lupini h13-3. the complex filament has an organization similar to that of the more common plain filament, but the subunits are perturbed in a pairwise fashion to generate a very distinctive set of three continuous ridges of density along the outer surface of the filament. in the three-dimensional map, the design of the complex filament is s ... | 1987 | 3656426 |
| molecular characterization of the vird operon from agrobacterium tumefaciens. | the agrobacterium tumefaciens ti plasmid virulence (vir) region contains at least six transcriptional units required for the efficient transfer of t-dna to the plant genome (vira, b, c, d, e, and g). we have reported that two proteins encoded by the 5'portion of the vird operon are required for a site-specific endonuclease activity that nicks the direct repeats which flank the t-dna. we have presented the nucleotide sequence for this portion of the operon. the nucleotide sequence of the remainde ... | 1987 | 3658701 |
| requirement of succinate dehydrogenase activity for symbiotic bacteroid differentiation of rhizobium meliloti in alfalfa nodules. | transmission electron microscopy was used to study the cellular morphologies of a wild-type rhizobium meliloti strain (l5-30), a nitrogen fixation-ineffective (fix-) succinate dehydrogenase mutant (sdh-) strain, and a fix+ sdh+ revertant strain within alfalfa nodules and after free-living growth in a minimal medium containing 27 mm mannitol plus 20 mm succinate. the results showed a requirement of succinate dehydrogenase activity for symbiotic differentiation and maintenance of r. meliloti bacte ... | 1987 | 3662521 |
| [denitrifying activity and generation time in 4 species of rhizobium]. | denitrifying capacity and doubling time were measured among 44 strains of rhizobium belonging to 4 species: b. japonicum, r. lupini, r. meliloti et r. leguminosarum. there was no correlation between doubling time and the rate of production of n2o in the presence of c2h2 in b. japonicum and r. lupini. in 38 other strains, only denitrifying capacity was measured. the percentage of strains showing denitrification capacity varied according to the species: 70% in b. japonicum, 90% in r. lupini, 37% i ... | 1987 | 3663388 |
| characterization of the lipopolysaccharide from a rhizobium phaseoli mutant that is defective in infection thread development. | the lipopolysaccharide (lps) from a rhizobium phaseoli mutant, ce109, was isolated and compared with that of its wild-type parent, ce3. a previous report has shown that the mutant is defective in infection thread development, and sodium dodecyl sulfate-polyacrylamide gel electrophoresis shows that it has an altered lps (k. d. noel, k. a. vandenbosch, and b. kulpaca, j. bacteriol. 168:1392-1462, 1986). mild acid hydrolysis of the ce3 lps released a polysaccharide and an oligosaccharide, ps1 and p ... | 1987 | 3667520 |
| dual control of agrobacterium tumefaciens ti plasmid virulence genes. | the virulence genes of nopaline (ptic58) and octopine (ptia6nc) ti plasmids are similarly affected by the agrobacterium tumefaciens ros mutation. of six vir region complementation groups (vira, virb, virg, virc, vird, and vire) examined by using fusions to reporter genes, the promoters of only two (virc and vird) responded to the ros mutation. for each promoter that was affected by ros, the level of expression of its associated genes was substantially elevated in the mutant. this increase was no ... | 1987 | 3667525 |
| chemotaxis to plant phenolic inducers of virulence genes is constitutively expressed in the absence of the ti plasmid in agrobacterium tumefaciens. | the virulence (vir) genes are required in the early stages of plant tumor formation and are located together on the tumor-inducing (ti) plasmid in agrobacterium tumefaciens. five of the vir genes are expressed inducibly in response to the following monocyclic phenolic compounds: acetosyringone, catechol, gallate, beta-resorcylate, protocatechuate, p-hydroxybenzoate, and vanillin. of these compounds, only the latter six, excluding vanillin [corrected] served as chemoattractants and only the latt ... | 1987 | 3667536 |
| deduced products of c4-dicarboxylate transport regulatory genes of rhizobium leguminosarum are homologous to nitrogen regulatory gene products. | we have sequenced two genes dctb and dctd required for the activation of the c4-dicarboxylate transport structural gene dcta in free-living rhizobium leguminosarum. the hydropathic profile of the dctb gene product (dctb) suggested that its n-terminal region may be located in the periplasm and its c-terminal region in the cytoplasm. the c-terminal region of dctb was strongly conserved with similar regions of the products of several regulatory genes that may act as environmental sensors, including ... | 1987 | 3671068 |
| plant expression signals of the agrobacterium t-cyt gene. | within the 5' and 3' non-coding regions of the t-cyt gene from the octopine t-dna of agrobacterium tumefaciens sequences required for expression of this gene in plant cells were identified by deletion mutagenesis. the results show that 184 bp of the 5' non-coding region and 270 bp of the 3' non-coding region are sufficient for wild-type expression. within the 5' non-coding region two essential expression signals were identified: (1.) an activator element located between -185 and -129 with respec ... | 1987 | 3671083 |
| effects of mutations in the tata box region of the agrobacterium t-cyt gene on its transcription in plant tissues. | we have generated mutations in the promoter region of the octopine type cytokinin gene of agrobacterium tumefaciens, and studied their effects on mrna formation in different plant species. the promoter region of this gene contains several putative tata boxes. phenotypic expression and northern blot hybridization showed that tata boxes are essential for expression, but that one tata box leads to wild-type transcript levels. analysis of the 5' ends of t-cyt transcripts by primer extension using rn ... | 1987 | 3671084 |
| septicemia with agrobacterium species from a permanent vena cephalica catheter. a case report. | a case of agrobacterium septicemia is reported in a 47-year-old woman with disseminated adenomcarcinoma mammae and a permanent vena cephalica catheter. | 1987 | 3673587 |
| agrobacterium tumefaciens virulence locus psca is related to the rhizobium meliloti exoc locus. | agrobacterium tumefaciens and rhizobium meliloti carry related genetic loci which have important roles in virulence and symbiosis. previously, it was shown that two virulence loci of a. tumefaciens, chva and chvb, are related to two r. meliloti symbiosis loci, ndva and ndvb, respectively (t. dylan, l. ielpi, s. stanfield, l. kashyap, c. douglas, m. yanofsky, e. nester, d. r. helinski, and g. ditta, proc. natl. acad. sci. usa 83:4403-4407, 1986). here we show that these two phytobacteria possess ... | 1987 | 3680180 |
| overdrive is a t-region transfer enhancer which stimulates t-strand production in agrobacterium tumefaciens. | introduction of a left or right synthetic border repeat together with the overdrive sequence in an octopine ti-plasmid deletion mutant, lacking the right border, resulted in the complete restoration of the oncogenicity of the mutant strain. however introduction of a border repeat without the overdrive, only restored oncogenicity partially. the overdrive sequence turned out to be able to stimulate the synthetic border mediated t-region transfer, independent of its orientation and position relativ ... | 1987 | 3684577 |
| biological nitrogen fixation: recent advances and future prospects. | current research on nitrogen fixation is basic to finding the knowledge needed for agriculture research in the future. genetic engineering is the best approach to increase biological nitrogen fixation and recent developments hold promise for this technology. this concept employing atmospheric nitrogen fixation instead of fertilizer to grow food and feed crops, while a complex engineering task, is possible. the opportunities and difficulties are discussed. | 1986 | 3704206 |
| enhanced instrumental sensitivity and selectivity for aminopeptidase profiling. | laser-excited fluorimetry has been applied to the identification of bacteria and fungus. the instrumental sensitivity and selectivity of the aminopeptidase profiling method has been enhanced by the use of laser excitation in conjunction with improved spectral and temporal background rejection. the linear dynamic range for the aminopeptidase technique has been increased by achieving a reduced lower limit of detection of the fluorescent tag, beta-naphthylamine. standard aminopeptidase methodology ... | 1986 | 3706731 |
| tomato golden mosaic virus a component dna replicates autonomously in transgenic plants. | phenotypically normal petunia plants carrying chromosomal inserts of either the tomato golden mosaic virus (tgmv) a or the b component dna, as single or tandem inserts, were obtained using an agrobacterium tumefaciens ti plasmid-based transformation system. southern hybridization analysis revealed that the tandem, direct-repeat a plants contained free single and double stranded a component dnas. no free b component dna was detected in plants carrying tandem repeats of the b component. progeny of ... | 1986 | 3708687 |
| effect of fungicide application on soybean-rhizobia symbiosis and isolation of fungicide-resistant strains of rhizobia japonicum. | | 1986 | 3719119 |
| sustained ethylene production in agrobacterium-transformed carrot disks caused by expression of the t-dna tms gene products. | agrobacterium-infected carrot disks continually produced elevated levels of ethylene. ethylene production was mediated by the elevated levels of auxin synthesized in transformed tissues. | 1986 | 3722126 |
| transformed cell clones as a tool to study t-dna integration mediated by agrobacterium tumefaciens. | a large number of tobacco sr1 cell clones transformed by the wild-type agrobacterium c58 have been analysed for the presence of screenable markers such as tumour morphology, opine synthesis and hormone dependence. distinct phenotypic classes were observed depending upon whether the cell clones were isolated from primary tumours or were obtained via cocultivation of protoplasts. these classes of tobacco sr1-c58 transformants appear to arise from errors in the ti plasmid (t-dna) transfer and integ ... | 1986 | 3723593 |
| iron requirement of rhizobium leguminosarum and secretion of anthranilic acid during growth on an iron-deficient medium. | rhizobium leguminosarum gf160 required iron for growth under aerobic conditions in a chemically defined medium. maximal growth of bacteria previously depleted in iron was obtained with approximately 50 microm unchelated ferric iron and with glucose as the only carbon source. growth under iron deficiency did not result in the production of detectable levels of siderophores of either the catechol or hydroxamate types. growing cells released a fe3+-reducing agent that was identified as anthranilic ... | 1986 | 3729413 |
| anthranilate-promoted iron uptake in rhizobium leguminosarum. | anthranilate promoted the uptake of ferric iron into iron-starved cells of rhizobium leguminosarum gf160. the uptake system was a saturable function of the concentration of ferric anthranilate. it was characterized by an apparent km of 6 microm and a vmax of 1.6 nmol/min/mg cell protein. uptake was temperature dependent and inhibited by the metabolic poisons arsenate and iodoacetate. the proton motive force may not be involved since no effect was demonstrated by the respiratory inhibitor sodium ... | 1986 | 3729414 |
| vira and virg control the plant-induced activation of the t-dna transfer process of a. tumefaciens. | the ti plasmid vir loci of agrobacterium tumefaciens are transcriptionally activated in response to signal molecules produced by plant cells to initiate the t-dna transfer process. we show that the ptia6 vir loci are organized as a single regulon whose induction by plants is controlled by vira and virg. mutations in vira result in attenuated induction. this locus is constitutively transcribed and noninducible. mutations in virg eliminate vir induction. this locus is constitutively transcribed, p ... | 1986 | 3731272 |
| organization, structure and symbiotic function of rhizobium meliloti nodulation genes determining host specificity for alfalfa. | in r. meliloti we have identified four nodulation genes determining plant host-range specificity and have designated them hsnabc and d. the genes code for 9.7, 41.7, 26.7, and 28.6 kd proteins, respectively, and are organized into two transcriptional units. mutations in these genes affect nodulation of their natural plant hosts medicago sativa and melilotus albus to different extents and hsnd mutants have an altered host-range. these nod- mutations are not complementable by nodulation genes of o ... | 1986 | 3731273 |
| proline biosynthesis encoded by the noc and occ loci of agrobacterium ti plasmids. | octopine or nopaline ti plasmids, or clones encoding their occ or noc loci, allowed proline auxotrophs of agrobacterium tumefaciens to utilize the appropriate arginyl opine as a proline substitute. arginine and ornithine substituted for proline only if the occ or noc loci were induced or made constitutive by mutation. these results support a report demonstrating a ti plasmid-encoded activity in a. tumefaciens which cyclizes ornithine to proline. | 1986 | 3733675 |
| a plant flavone, luteolin, induces expression of rhizobium meliloti nodulation genes. | the symbiotic interaction of rhizobium meliloti and alfalfa results in the formation of nitrogen-fixing root nodules. rhizobium meliloti nodabc genes are required for the early host responses of cortical cell divisions and root hair curling. the induction of nodabc expression by alfalfa exudates demonstrates host-symbiont signaling at an early stage in nodule development. the inducer molecule for nodabc expression was isolated from plant exudate by constructing a nodabc-lacz fusion to monitor th ... | 1986 | 3738520 |
| fractionation of rhizobium leguminosarum cells into outer membrane, cytoplasmic membrane, periplasmic, and cytoplasmic components. | rhizobium leguminosarum cells were separated into four distinct fractions by using density gradient centrifugation for the separation of the outer and cytoplasmic membranes and lysozyme-edta treatment of whole cells for the isolation of the periplasmic and cytoplasmic fractions. these methods allowed the subcellular localization of r. leguminosarum proteins. | 1986 | 3745116 |
| galactose metabolism in rhizobium meliloti l5-30. | data from previous studies of rhizobium meliloti mutants have been consistent with the catabolism of hexoses via the entner-doudoroff pathway. however, galactose metabolism was not impaired in those mutants. we show here by enzymatic assay and by identification of a galactose mutant lacking 2-keto-3-deoxy-6-phosphogalactonate aldolase that the de ley-doudoroff pathway is used for galactose metabolism. mutants in this pathway have not been previously reported for any organism. | 1986 | 3745118 |
| two gene clusters of rhizobium meliloti code for early essential nodulation functions and a third influences nodulation efficiency. | a plafr1 cosmid clone (ppp346) carrying the nodulation region of the symbiotic plasmid prme41b was isolated from a gene library of rhizobium meliloti 41 by direct complementation of a nod- deletion mutant of r. meliloti. agrobacterium tumefaciens and rhizobium species containing ppp346 were able to form ineffective nodules on alfalfa. the 24-kilobase insert in ppp346 carries both the common nodulation genes and genes involved in host specificity of nodulation. it was shown that these two regions ... | 1986 | 3745124 |
| formation in rhizobium and agrobacterium spp. of a 235-kilodalton protein intermediate in beta-d(1-2) glucan synthesis. | beta-d(1-2) glucan was synthesized by agrobacterium and rhizobium spp. in vitro with enzymes from the internal membranes upon the addition of udf glucose and mg2+ or mn2+. an intermediate containing protein and beta-d(1-2) glucan was formed during the reaction. it could be precipitated with trichloroacetic acid or separated by polyacrylamide gel electrophoresis under denaturing conditions. after detection with coomassie blue or a radioactive substrate, the intermediate appeared as a 235-kilodalt ... | 1986 | 3745125 |
| rhizobium sp. strain ors571 grows synergistically on n2 and nicotinate as n sources. | rhizobium sp. strain ors571 conducts synergistic, free-living n2 fixation and nicotinate oxidation. explicitly, ors571 is able to fix n2 aerobically because 6-oh-nicotinate acts as an intracellular o2 sink. because 6-oh-nicotinate oxidation is mandatory for aerobic, free-living n2 fixation and because the synergistic processes yield ammonium from substrates (as the nitrogen source for growth), ors571 is not a diazotroph. | 1986 | 3753598 |
| control of a futile urea cycle by arginine feedback inhibition of ornithine carbamoyltransferase in agrobacterium tumefaciens and rhizobia. | in agrobacterium tumefaciens and rhizobia arginine can be used as the sole nitrogenous nutrient via degradation by an inducible arginase. these microorganisms were found to exhibit arginine inhibition of ornithine carbamoyltransferase activity. this inhibition is competitive with respect to ornithine (km for ornithine = 0.8 mm; ki for arginine = 0.05 mm). this type of urea cycle regulation has not been observed among other microorganisms which degrade arginine via an arginase. the competitive pa ... | 1986 | 3758074 |
| molecular characterization of a host-range-determining locus from agrobacterium tumefaciens. | the virulence loci play an essential role in tumor formation by agrobacterium tumefaciens. this study focused on the virc locus, which affects the host range agrobacterium species. virc mutants display an attenuated or avirulent phenotype on certain host plants, but remain fully virulent on other plant hosts. the nucleotide sequence revealed that the virc locus of ptia6nc is an operon consisting of two open reading frames. these two open reading frames, designated virc1 and virc2, encode protein ... | 1986 | 3759904 |
| biosynthesis of a galactose-and galacturonic acid-containing polysaccharide in rhizobium meliloti. | previous work showed that two different strains derived from a culture of rhizobium meliloti 102f51 differed with respect to phage specificity, agglutinability by alfalfa seed lectin, and synthesis of a galactose-containing polysaccharide (r. a. ugalde, h. handelsman, and w. j. brill, j. bacteriol. 166:148-154, 1986). inner membranes from the more competitive strain incorporated galactose from udp-galactose when a thermostable factor was present. this factor has now been identified as udp-galact ... | 1986 | 3759905 |
| the kinetics of the reactions of parasponia andersonii hemoglobin with oxygen, carbon monoxide, and nitric oxide. | hemoglobin i was isolated from nodules formed on the roots of parasponia andersonii inoculated with rhizobium strain cp 283. the rate of oxygen dissociation from parasponia hemoglobin increases about 12-fold between ph 4 and 7, with apparent pk 6.4, to reach a limiting value of 14.8s-1. the optical spectrum of oxyhemoglobin in the visible region is also dependent on ph with pk near 6.4. the rate constant for oxygen combination with parasponia hemoglobin increases about 7-8-fold between ph 4 and ... | 1986 | 3759986 |
| a family of related atp-binding subunits coupled to many distinct biological processes in bacteria. | many biological processes are coupled to atp hydrolysis. we describe here a class of closely related atp-binding proteins, from several bacterial species, which are associated with a variety of cellular functions including membrane transport, cell division, nodulation in rhizobium and haemolysin export. these proteins comprise a family of structurally and functionally related subunits which share a common evolutionary origin, bind atp and probably serve to couple atp hydrolysis to each of these ... | 1986 | 3762694 |
| time required for tumor induction by agrobacterium tumefaciens. | cellulose-minus mutants of agrobacterium tumefaciens retain virulence but can be removed from wound sites by washing with water. washing of bryophyllum diagremontiana leaves inoculated with a cellulose-minus mutant was used to determine the minimum time the bacteria must be present for tumor induction. this time was 4 to 8 h. | 1986 | 3767365 |
| nodulation of legumes by rhizobium: the recognized root? | | 1986 | 3768953 |
| agrobacterium tumefaciens and the susceptible plant cell: a novel adaptation of extracellular recognition and dna conjugation. | | 1986 | 3768954 |
| transport of gamma-butyrobetaine in an agrobacterium species isolated from soil. | an agrobacterium sp. isolated from soil by selective growth on gamma-butyrobetaine (gamma-trimethylaminobutyrate) as the sole source of both carbon and nitrogen has been shown to possess an inducible transport system for this growth substrate. this transport system has a kt of 0.5 microm and a maximal velocity of 3.8 nmol/min per mg (dry weight). the influx of gamma-butyrobetaine is optimal at ph 8.5 and operates against a concentration gradient. the transport system shows a high specificity for ... | 1986 | 3782024 |
| mapping and cloning of a fla-che region of the rhizobium meliloti chromosome. | we constructed a genetic map of the fla-che region of the rhizobium meliloti chromosome using cotransduction with bacteriophage phi m12. several other chromosomal markers located in the general area are included in the map. we isolated plasmids carrying wild-type dna inserts that complement the mapped mutations from a genomic library carried in the broad-host-range vector plafr1. the complementation data obtained from the clones confirmed the contransduction map and clarified the exact order of ... | 1986 | 3782025 |
| correlation between extracellular fibrils and attachment of rhizobium leguminosarum to pea root hair tips. | as part of a project meant to characterize molecules involved in nodulation, a semiquantitative microscopic assay was developed for measuring attachment of rhizobium leguminosarum cells to pea root hair tips, i.e., the site at which r. leguminosarum initiates nodulation. this form of attachment, designated as cap formation, was dependent on the incubation ph and growth phase, with optimal attachment at ph 7.5 and with bacteria in the early stationary phase of growth. addition of glucose to the g ... | 1986 | 3782027 |
| molecular cloning and expression of rhizobium fredii usda 193 nodulation genes: extension of host range for nodulation. | dna hybridization with the cloned nodulation region of rhizobium meliloti as a probe revealed dna homology with four hindiii fragments, 12.5, 6.8, 5.2, and 0.3 kilobases (kb) in size, of the symbiotic plasmid prjausda193. both hybridization and complementation studies suggest that the common nodulation genes nodabc and nodd of r. fredii usda 193 are present on the 5.2-kb hindiii and 2.8-kb ecori fragments, respectively, of the sym plasmid. both fragments together could confer nodulation ability ... | 1986 | 3782034 |
| the hypervirulence of agrobacterium tumefaciens a281 is encoded in a region of ptibo542 outside of t-dna. | we used a binary-vector strategy to study the hypervirulence of agrobacterium tumefaciens a281, an l,l-succinamopine strain. strain a281 is hypervirulent on several solanaceous plants. we constructed plasmids (pcs65 and pcs277) carrying either the transferred dna (t-dna) or the remainder of the tumor-inducing (ti) plasmid (peha101) from this strain and tested each of these constructs in trans with complementary regions from heterologous ti plasmids. hypervirulence on tobacco could be reconstruct ... | 1986 | 3782037 |
| mutations in rhizobium phaseoli that lead to arrested development of infection threads. | two rhizobium phaseoli mutants, isolated previously by tn5 mutagenesis, elicited infection threads which ceased development prematurely, usually within root hairs. these infection threads were wide, globular, and otherwise altered in morphology, compared with normal infection threads. anatomy and division of the root cortical cells during initial stages of nodule morphogenesis appeared normal. however, later nodule differentiation deviated considerably from normal development, and release of bac ... | 1986 | 3782040 |
| biosynthesis of rhizobium trifolii capsular polysaccharide: enzymatic transfer of pyruvate substitutions into lipid-bound saccharide intermediates. | the activity of capsular polysaccharide pyruvyltransferase catalyzing the pyruvylation of acidic heteropolysaccharide was measured in rhizobium trifolii 843 and 0403 rif. this enzyme activity was determined with edta-treated cells, uridine diphosphate-sugar precursors, and phosphoenol [1-14c]pyruvate. activity was measured by the incorporation of radioactivity into organic solvent-soluble glycoconjugates. enzymatic pyruvylation of capsular polysaccharide occurred from phosphoenolpyruvate at the ... | 1986 | 3782043 |
| congo red absorption and cellulose synthesis by rhizobiaceae. | congo red uptake by rhizobium colonies from yeast extract-mannitol-mineral salts-congo red-agar plates was related with the cellulose content in the cell capsule of the bacteria. | 1986 | 3789702 |
| synthesis of 3,6-dideoxy-3-(methylamino)hexoses for g.l.c.-m.s. identification of rhizobium lipopolysaccharide components. | a direct synthetic route from methyl alpha-d-glucopyranoside to 3,6-dideoxy-3-(methylamino)hexoses having the d-gluco, d-galacto, and d-manno configurations has been developed. methyl alpha-d-glucoside was converted into the 4,6-o-benzylidene-2,3-di-o-tosyl derivative, which was then transformed into the 4-o-benzyl-6-deoxy 2,3-ditosylate (5) by successive reductive cleavage of the acetal ring, iodination, and reduction. the intermediate 5 was readily converted into the allo 2,3-epoxide, which yi ... | 1986 | 3791291 |
| cell surface polysaccharides from bradyrhizobium japonicum and a nonnodulating mutant. | the cell surface polysaccharides of wild-type bradyrhizobium japonicum usda 110 and a nonnodulating mutant, strain hs123, were analyzed. the capsular polysaccharide (cps) and exopolysaccharide (eps) of the wild type and the mutant strain do not differ in their sugar composition. cps and eps are composed of mannose, 4-o-methylgalactose/galactose, glucose, and galacturonic acid in a ratio of 1:1:2:1, respectively. h nuclear magnetic resonance spectra of the eps and cps of the wild type and mutant ... | 1987 | 3793715 |
| physical association between the peribacteroid membrane and lipopolysaccharide from the bacteroid outer membrane in rhizobium-infected pea root nodule cells. | monoclonal antibodies were used as cytochemical markers to study surface interactions between endosymbiotic rhizobium bacteroids from pea root nodules and the encircling peribacteroid membranes, which are of plant origin. monoclonal antibodies that react with rhizobium lipopolysaccharide (lps) or with a plant membrane glycoprotein were used as markers for material from the bacteroid outer membrane or the peribacteroid membrane, respectively. membrane-enclosed bacteroids were isolated from nodule ... | 1986 | 3793795 |
| bacterial carbon-phosphorus lyase: products, rates, and regulation of phosphonic and phosphinic acid metabolism. | carbon-phosphorus bond cleavage activity, found in bacteria that utilize alkyl- and phenylphosphonic acids, has not yet been obtained in a cell-free system. given this constraint, a systematic examination of in vivo c-p lyase activity has been conducted to develop insight into the c-p cleavage reaction. six bacterial strains were obtained by enrichment culture, identified, and characterized with respect to their phosphonic acid substrate specificity. one isolate, agrobacterium radiobacter, was s ... | 1987 | 3804975 |
| 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 |
| expression of agrobacterium tumefaciens t-dna gene 7 in xenopus laevis oocytes. | the expression of agrobacterium tumefaciens t-dna gene 7 was investigated in xenopus laevis oocytes. cloned dna injected into oocytes consisted of t-dna sequences derived from octopine type ti plasmid b6-806 and t-dna attached to plant dna sequences at the left junction in crown gall tumors. transcription initiation sites observed in oocytes were similar to those for transcript 7 in crown gall tumors. quantitative differences in transcription occurred depending on the flanking sequences of the i ... | 1986 | 3814121 |
| 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 |
| at least two nodd genes are necessary for efficient nodulation of alfalfa by rhizobium meliloti. | a rhizobium meliloti dna region (nodd1) involved in the regulation of other early nodulation genes has been delimited by directed tn5 mutagenesis and its nucleotide sequence has been determined. the sequence data indicate a large open reading frame with opposite polarity to noda, -b and -c, coding for a protein of 308 (or 311) amino acid residues. tn5 insertion within the gene caused a delay in nodulation of medicago sativa from four to seven days. hybridization of nodd1 to total dna of rhizobiu ... | 1986 | 3820290 |
| 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 |
| characterization of the anomalous infection and nodulation of subterranean clover roots by rhizobium leguminosarum 1020. | anomalous nodulation of trifolium subterraneum (subterranean clover) roots by rhizobium leguminosarum 1020 was examined as a model of modified host-specificity in a rhizobium-legume symbiosis. consistent with previous reports, these nodules (i) appeared most often at sites of secondary root emergence, (ii) were ineffective in nitrogen fixation and (iii) were as numerous as nodules formed by an effective rhizobium trifolii strain. r. leguminosarum 1020, grown on agar plates or in the clover root ... | 1985 | 3831234 |
| primary structure of the soybean nodulin-23 gene and potential regulatory elements in the 5'-flanking regions of nodulin and leghemoglobin genes. | the nodulin-23 gene of soybean is one of the most abundantly transcribed genes induced during symbiosis with rhizobium. using a plasmid (pnod25) from a nodule cdna library, we have isolated the nodulin-23 gene from a soybean genomic library. nucleotide sequence analysis of the cdna and of the genomic clone indicated that the coding region of this gene is 669 bp long and is interrupted by a single intron of about 530 bp. the deduced protein sequence suggests that nodulin-23 may have a signal sequ ... | 1985 | 3839073 |
| identification of the promoter of the pseudomonas gene coding for carboxypeptidase g2. | a 213-bp region of noncoding dna upstream of the atg start codon of the pseudomonas carboxypeptidase g2 (cpg2) structural gene has been shown to contain the cpg2 promoter. the mrna start point (+1) on the dna sequence has been identified by mapping the 5' end of the cpg2 transcript. the identified promoter region contains a -10 region (tataag) that closely resembles the escherichia coli consensus sequence (tataat), but has no easily recognisable -35 region. the lack of homology in the -35 region ... | 1985 | 3839252 |
| [analysis of plasmids in rhizobium meliloti strains of different geographical origin]. | the presence of 1-3 additional plasmids ranging from 16 to 400 md in mol mass was revealed in bacterial cells besides a megaloplasmid in most of 34 rhizobium meliloti strains studied. no correlation was found between plasmids pattern and geographical origin of isolation source of the strain analyzed. | 1985 | 3842753 |
| [effect of agrobacterium tumefaciens (smith and town). conn. on the functional properties of human blood lymphocytes]. | agrobacterium tumefaciens has been shown to affect the proliferation of intact lymphocytes as well as lymphocytes stimulated by pha action. inoculation of bacteria into the cultures of intact lymphocytes and incubation during 72 h resulted in increased incorporation of [3h]-thymidine into the dna of cultivated cells. the bacteria are capable of inhibition of lymphocytes proliferation stimulated by pha. | 1985 | 3842755 |
| t-dna border sequences required for crown gall tumorigenesis. | similar 23-base-pair (bp) direct repeats occur at the ends of two adjacent but noncontiguous t-dnas, tl and tr (left and right t-dna), in the tumor-inducing plasmid ptia6nc. thus, three border repeats lie right and one lies left of tl, which carries the genes needed for tumor maintenance. to determine whether t-dna transfer and integration (subsequently called t-dna transmission) require sequences in addition to the 23-bp border repeat, we constructed a deletion removing the three potential tl r ... | 1985 | 3860847 |
| exopolysaccharide-deficient mutants of rhizobium meliloti that form ineffective nodules. | by screening with the fluorescent stain calcofluor, we have isolated 26 independent transposon tn5 insertion mutants of rhizobium meliloti that are deficient in the production of a known extracellular polysaccharide (exo-). the mutants belonged to six distinct genetic groups based on the ability of their exo- phenotype to be complemented by different recombinant plasmids from a r. meliloti clone bank. with few exceptions, all of the mutants formed ineffective (non-nitrogen-fixing) nodules on alf ... | 1985 | 3862129 |
| plant-associated agricultural applications of genetically engineered microorganisms: projections and constraints. | | 1985 | 3864203 |
| rhizobium leguminosarum genes involved in early stages of nodulation. | nodulation genes from rhizobium leguminosarum have been subcloned and transferred to a strain of r. phaseoli with its symbiotic plasmid deleted (and therefore its nodulation and nitrogen fixation genes). normal infection and nodule development occurred when these strains were added to the roots of pisum sativum (peas) and vicia hirsuta. the pea nodules were examined by electron microscopy; bacteroid forms were seen surrounded by peribacteroid membranes and using immuno-gold labelling it was show ... | 1985 | 3867677 |
| symbiotic nitrogen fixation: developmental genetics of nodule formation. | | 1985 | 3868494 |
| metabolism of antibiotic resistant mutants of rhizobium sp. as influenced by different temperature regimes. | | 1985 | 3869604 |
| isolation of genes (nif/hup cosmids) involved in hydrogenase and nitrogenase activities in rhizobium japonicum. | recombinant cosmids containing a rhizobium japonicum gene involved in both hydrogenase (hup) and nitrogenase (nif) activities were isolated. an r. japonicum gene bank utilizing broad-host-range cosmid plafr1 was conjugated into hup- nif- r. japonicum strain sr139. transconjugants containing the nif/hup cosmid were identified by their resistance to tetracycline (tcr) and ability to grow chemoautotrophically (aut+) with hydrogen. all tcr aut+ transconjugants possessed high levels of h2 uptake acti ... | 1985 | 3882669 |
| extension of the host range of escherichia coli vectors by incorporation of rsf1010 replication and mobilization functions. | the broad-host-range vectors psup104, psup106, psup204, psup304, and psup404 are based on conventional escherichia coli vectors (such as pbr325 and pacyc184) which have been modified to include the mobilization and broad-host-range replication functions of the incq plasmid rsf1010. these vector plasmids now can be maintained in a wide range of bacterial genera including rhizobium, agrobacterium, and pseudomonas. they are efficiently mobilized by rp4 and thus are of particular interest for bacter ... | 1985 | 3891734 |
| conservation of nif- and species-specific domains within repeated promoter sequences from fast-growing rhizobium species. | in the fast-growing rhizobium species, repeated dna sequences, which include the promoter region of the nif hdk operon have been described. these repeated sequences are promoters which specifically activate transcription in the endosymbiotic state. hybridization analysis of these sequences from r. trifolii has revealed that they may be involved in the species-specific activation of the various genes whose transcription they promote. comparative analysis of various copies of these repeated sequen ... | 1985 | 3892479 |