Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
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| virg of agrobacterium tumefaciens plasmid ptic58 encodes a dna-binding protein. | virulence genes of the agrobacterium tumefaciens ti plasmid are positively regulated by the products of vira and virg. to study the dna-binding properties of the virg protein, a translational fusion between virg and the trpe gene of escherichia coli was constructed, and antiserum was raised against the encoded fusion protein. using this antiserum, a protein of mr congruent to 29,000, a size similar to that calculated from the virg nucleotide sequence, was detected in an e. coli strain harbouring ... | 1989 | 2664419 |
| major integral membrane protein immunogens of treponema pallidum are proteolipids. | a number of the major pathogen-specific immunogens of treponema pallidum were characterized recently as amphiphilic, integral membrane proteins by phase partitioning with triton x-114 (j. d. radolf, n. r. chamberlain, a. clausell, and m. v. norgard. infect. immun. 56:490-498, 1988). in the present study, we demonstrated that the same membrane immunogens (designated as detergent phase proteins [dpps]) become radiolabeled upon in vitro incubation of t. pallidum with various 3h-labeled fatty acids. ... | 1989 | 2668191 |
| construction of an agrobacterium tumefaciens c58 reca mutant. | clones encoding the reca gene of agrobacterium tumefaciens c58 were isolated from a cosmid bank by complementation of an escherichia coli reca mutation. subcloning and mutagenesis with the lacz fusion transposon tn3hoho1 located the agrobacterium reca gene to a 1.3-kilobase segment of dna. beta-galactosidase expression from the fusions established the direction in which the gene was transcribed. the gene restored homologous recombination as well as dna repair functions in e. coli reca mutants. s ... | 1989 | 2676971 |
| firefly luciferase as a reporter enzyme for measuring gene expression in vegetative and symbiotic rhizobium meliloti and other gram-negative bacteria. | a dna segment carrying a cdna copy of the luciferase gene (luc) of the north american firefly photinus pyralis, fused to the lambda pr promoter and expressed in escherichia coli [de wet et al., proc. natl. acad. sci. usa 82 (1985) 7870-7873], was inserted into a broad-host-range plasmid vector and established in a variety of gram-negative bacteria. luciferase activity, expressed from the lambda pr promoter, was detected in both intact cells and extracts prepared from cells of strains of rhizobiu ... | 1989 | 2680767 |
| [the study of binding of the virg gene product with the vird gene promotor region of the agrobacterium tumefaciens ti-plasmid c58]. | the 1.5 kb ecori--hindiii fragment of the ptic58 containing the vird regulatory sequence demonstrates a constitutive promoter activity in e. coli background and an inducible one in agrobacterium. the virg gene was cloned in ptz19r plasmid. to reveal the virg product--vird regulatory sequence interaction a few protein fractions of e. coli harbouring the obtained recombinant plasmid ptz19g lysate were used. page-retardation assay revealed the specific binding between the 1.5 kb dna fragment contai ... | 1989 | 2682221 |
| nodo, a new nod gene of the rhizobium leguminosarum biovar viciae sym plasmid prl1ji, encodes a secreted protein. | the region of the rhizobium leguminosarum biovar viciae sym plasmid prl1ji, responsible for the production and secretion of a previously described 50-kilodalton protein (r. a. de maagd, c. a. wijffelman, e. pees, and b. j. j. lugtenberg, j. bacteriol. 170:4424-4427, 1988), was cloned and its nucleotide sequence was determined. a new nod gene, nodo, preceded by a poorly conserved nod box, was identified and its transcriptional start site was determined. comparison of its predicted protein product ... | 1989 | 2687250 |
| antibiotic inactivating enzymes from a clinical isolate of agrobacterium radiobacter. | 1989 | 2708185 | |
| nucleotide sequence and analysis of the plant-inducible locus pinf from agrobacterium tumefaciens. | several loci on the tumor-inducing plasmid from agrobacterium tumefaciens were transcriptionally activated in the presence of wounded plant tissue or extracts. the inducible virulence loci were required for efficient tumor formation. in contrast, the plant-inducible locus pinf was not observed to be absolutely essential for virulence. mutants in pinf showed an attenuated virulence on a variety of dicotyledonous hosts, and this attenuation became more pronounced with decreasing numbers of bacteri ... | 1989 | 2708311 |
| cooperative binding of agrobacterium tumefaciens vire2 protein to single-stranded dna. | the vire2 protein of agrobacterium tumefaciens ti plasmid ptia6 is a single-stranded-dna-binding protein. density gradient centrifugation studies showed that it exists as a tetramer in solution. monomeric vire2 active in dna binding could also be obtained by using a different protein isolation procedure. vire2 was found to be thermolabile; brief incubation at 37 degrees c abolished its dna-binding activity. it was insensitive to the sulfhydryl-specific reagent n-ethylmaleimide. removal of the ca ... | 1989 | 2708313 |
| biochemical characterization of avirulent agrobacterium tumefaciens chva mutants: synthesis and excretion of beta-(1-2)glucan. | the chva gene product of agrobacterium tumefaciens is required for virulence and attachment of bacteria to plant cells. three chva mutants were studied. in vivo, they were defective in the synthesis, accumulation, and secretion of beta-(1-2)glucan; however, the 235-kilodalton (kda) protein known to be involved in the synthesis of beta-(1-2)glucan (a. zorreguieta and r. ugalde, j. bacteriol. 167:947-951, 1986) was present and active in vitro. was present and active in vitro. two molecular forms o ... | 1989 | 2708321 |
| lipid a with 2,3-diamino-2,3-dideoxy-glucose in lipopolysaccharides from slow-growing members of rhizobiaceae and from "pseudomonas carboxydovorans". | lipid a's from two bradyrhizobium species and from the phylogenetically closely related species "pseudomonas carboxydovorans" were found to contain 2,3-diamino-2,3-dideoxy-glucose as lipid a backbone sugar. in contrast, three representatives of the genus rhizobium, as well as the phylogenetically related species agrobacterium tumefaciens, contain solely glucosamine as lipid a backbone sugar. these findings support independent studies on the phylogenetical relatedness based on 16s rrna-data of th ... | 1989 | 2719525 |
| recovery of agrobacterium tumefaciens t-dna molecules from whole plants early after transfer. | a system for the analysis of independent t-dna transfer events from agrobacterium to plants is described. the complete t-dna except for the 25 bp border sequences was replaced by one genome of a plant virus so that upon transfer to the plant, a viable replicon is produced by circularization. rescue of virus from such infected plants allowed analysis of dna sequences at or close to the ends of t-dna molecules. a rather conserved right border remnant of three nucleotides was found, whereas the seq ... | 1989 | 2720788 |
| saturation mutagenesis of the octopine synthase enhancer: correlation of mutant phenotypes with binding of a nuclear protein factor. | a 16-base-pair palindrome from the agrobacterium tumefaciens octopine synthase gene functions as a constitutive enhancer in plant protoplasts. degenerate oligonucleotide mutagenesis provided single base substitutions at every position in the element and a number of multiple base substitutions. the effects of these changes were determined in transient expression assays with tobacco and maize protoplasts. the majority of single and double base changes had little effect on the activity of the octop ... | 1989 | 2726750 |
| opines stimulate induction of the vir genes of the agrobacterium tumefaciens ti plasmid. | upon incubation of agrobacterium tumefaciens a348 with acetosyringone, the vir genes encoded by the ti (tumor-inducing) plasmid are induced. the addition of certain opines, including octopine, nopaline, leucinopine, and succinamopine, enhanced this induction 2- to 10-fold. the compounds mannopine, acetopine, arginine, pyruvate, and leucine did not stimulate the induction of the vir genes to such an extent. the enhancement of vir gene induction by opines depended on acetosyringone and the genes v ... | 1989 | 2738020 |
| isolation and characterization of an ipt gene from the ti plasmid bo542. | a 1.9 kb clone of the t-dna region of the agrobacterium tumefaciens ti plasmid bo542 which exhibited homology to the isopentenyl transferase (ipt) locus of ptia6 was identified by low stringency dna hybridization. introduction of this segment of ptibo542 dna into cells of nicotiana tabacum or n. glauca caused tumor formation in vivo, and allowed hormone independent growth in vitro. furthermore, this dna segment complemented ipt mutant strains of a. tumefaciens, restoring their ability to cause t ... | 1989 | 2747621 |
| delineation of the regulatory region sequences of agrobacterium tumefaciens virb operon. | a virb-lacz translational fusion was constructed to monitor expression of the agrobacterium tumefaciens virb operon. expression of the fusion gene was dependent on the presence of ptia6 vira, virg, and a plant factor acetosyringone. analysis of deletion mutants, constructed by exonuclease bal31 digestion, showed that 68 residues upstream of the virb transcription initiation site was necessary for its expression. a tt----cc substitution at positions -62 and -61 led to a 7 fold reduction in virb e ... | 1989 | 2748333 |
| properties of l-lysine epsilon-dehydrogenase from agrobacterium tumefaciens. | lysine epsilon-dehydrogenase, which has been purified to homogeneity from the extract of agrobacterium tumefaciens icr 1600, had a molecular weight of approximately 78,000 and consisted of two subunits identical in molecular weight (about 39,000). the enzyme showed a high substrate specificity. in addition to l-lysine, s-(beta-aminoethyl)-l-cysteine was deaminated by the enzyme, but to a far lesser extent. nad+ and some nad+ analogs (deamino-nad+ and 3-acetylpyridine-nad+) served as a cofactor. ... | 1989 | 2768207 |
| application of gas-liquid chromatography to the routine identification of nonfermenting gram-negative bacteria in clinical specimens. | a total of 430 strains of glucose-nonfermenting gram-negative bacteria representing 35 species were analyzed for their cellular fatty acid composition by gas-liquid chromatography (glc). on the basis of qualitative differences in their cellular fatty acid composition, these bacteria could be divided into 19 distinct chromatographic groups. eight pseudomonas species, achromobacter xylosoxidans, group vd, and agrobacterium radiobacter were identified from their fatty acid compositions alone. the o ... | 1989 | 2768442 |
| dna transfer from agrobacterium to zea mays or brassica by agroinfection is dependent on bacterial virulence functions. | dna transfer from agrobacterium tumefaciens, a soil bacterium, to the non-host graminaceous monocotyle-donous plant zea mays, was analysed using the recently developed technique of agroinfection. agroinfection of z. mays with maize streak virus using strains of a. tumefaciens carrying mutations in the ptic58 virulence region showed an almost absolute dependence on the products of the bacterial virc genes. in contrast, agroinfection of the control host brassica rapa with cauliflower mosaic virus ... | 1989 | 2770696 |
| activation of l-lysine epsilon-dehydrogenase from agrobacterium tumefaciens by several amino acids and monocarboxylates. | the activation of lysine epsilon-dehydrogenase [ec 1.4.1.] by l-lysine was dependent on lysine concentration and was accompanied by association of the dimeric enzymes to a tetramer. the lysine concentration required for the half-maximal activation was 0.28 mm, which was lower than the km value for l-lysine. in addition to l-lysine, several compounds, which were neither substrates nor inhibitors, activated the enzyme. the compounds which activated the enzyme have common structural characteristics ... | 1989 | 2777754 |
| catheter infection caused by an unusual pathogen, agrobacterium radiobacter. | the genus agrobacterium is composed of several phytopathogenic species occurring worldwide in soils. one nontumorigenic species, agrobacterium radiobacter, has occasionally been isolated from clinical specimens, but its pathogenic role in these cases has been difficult to ascertain since agrobacteria are usually isolated in association with other bacteria. we report the case of a central venous catheter infection and present the characteristics of a. radiobacter. | 1989 | 2778076 |
| membrane topology and functional analysis of the sensory protein vira of agrobacterium tumefaciens. | the vira gene of agrobacterium tumefaciens encodes an inner membrane that mediates the transcriptional activation of virulence genes in response to plant signal molecules. we report here a functional analysis of the n-terminal, c-terminal and periplasmic domains of vira in transmembrane signalling. first, we show that vira has a transmembrane topology by analysis of the alkaline phosphatase activities, determined by several vira-phoa gene fusions. second, we report here the construction of sever ... | 1989 | 2792074 |
| requirement for chemotaxis in pathogenicity of agrobacterium tumefaciens on roots of soil-grown pea plants. | agrobacterium tumefaciens tn5 mutants deficient in chemotaxis to root exudates were used to study the significance of chemotaxis in crown gall pathogenesis. mutants deficient in motility and in chemotaxis were fully virulent when inoculated by direct immersion in inoculum, followed by growth for 2 weeks in moist growth pouches. ability of mutant bacteria to move through soil to infect roots was tested by planting wounded seedlings into air-dried soil or sand that had been infested with inoculum. ... | 1989 | 2793831 |
| characterization of the vira virulence gene of the nopaline plasmid, ptic58, of agrobacterium tumefaciens. | we have determined the complete nucleotide sequence of a 4.8 kilobase fragment encompassing the vira locus of the nopaline-type plasmid, ptic58, of agrobacterium tumefaciens. vira is composed of a single open reading frame of 2499 nucleotides, capable of encoding a protein of 91.3 kilodaltons. a trpe::vira gene fusion was used to confirm the reading frame of vira. high nucleotide and amino acid sequence homologies were observed between ptic58 vira and the vira sequences of three octopine-type pl ... | 1989 | 2796735 |
| regulatory domains of the gmhsp17.5-e heat shock promoter of soybean. | promoter domains required for in vivo transcriptional expression of soybean heat shock gene gmhsp17.5-e were identified by insertion-deletion mutagenesis with transgenic expression monitored in agrobacterium tumefaciens-incited tumors of sunflower. removal of the tata-distal domain from position -1175 to position -259 had little effect on overall activity. the four regions contributing to promoter activity identified by this study all map within 244 base pairs from the start of transcription. th ... | 1989 | 2796991 |
| ti plasmid-controlled chromosome transfer in agrobacterium tumefaciens. | in octopine-type a. tumefaciens r10, transfer of chromosomal arginine degradation genes (arc genes) was observed under conditions in which ti plasmid transfer took place. however, transconjugants that had acquired the arc genes but not the ti plasmid were recovered. during this process, several other chromosomal genes, such as genes encoding phage resistances or genes complementing a galactose utilization mutation or a glycine-serine auxotrophy, were transferred from strain r10 to the recipient. | 1989 | 2808306 |
| [transfer of the agrobacterial gene for cytokinin biosynthesis into tobacco plants]. | the gene transfer into plants using the genetic engineering methods gives us the possibility to obtain transgeneric plants having acquired the new traits. some bacterial genes can be used for this purpose. obtaining of a transgeneric plant harbouring the cytokinin synthesis gene ipt (gene 4) from the t-dna of agrobacterium tumefaciens ti-plasmid seems to be useful. the expression of tumor agrobacterial ipt gene in transformed plant cells interferes with the normal growth and regulation of the wh ... | 1989 | 2811903 |
| in vitro activities of new oral beta-lactams and macrolides against campylobacter pylori. | the in vitro activities of amoxicillin, cefuroxime, ceftetrame, cefetamet, cefixime, tigemonam, erythromycin, roxithromycin, and dirithromycin against 30 clinical isolates of campylobacter pylori were determined by an agar dilution technique. roxithromycin and amoxicillin (mics for 90% of isolates tested, 0.01 and 0.06 micrograms/ml, respectively) were the most active antibiotics tested, but all strains were susceptible to all antimicrobial agents tested. | 1989 | 2817868 |
| double-stranded cleavage of t-dna and generation of single-stranded t-dna molecules in escherichia coli by a vird-encoded border-specific endonuclease from agrobacterium tumefaciens. | the vird locus of agrobacterium tumefaciens ti plasmid ptia6 was sequenced. computer analysis of the sequence indicated five possible open reading frames (orfs) within this locus. two additional orfs were identified distal to this locus. however, only two polypeptides of apparent molecular masses 16 and 56 kilodaltons, the products of orfs 1 and 2, were detected in escherichia coli, both in vivo and in an in vitro coupled transcription-translation system. the vird locus was cloned in expression ... | 1987 | 2822660 |
| regulation of the vir genes of agrobacterium tumefaciens plasmid ptic58. | the virulence (vir) region of ptic58 was screened for promoter activities by using gene fusions to a promoterless lux operon in the broad-host-range vector pucd615. active vir fragments contained the strongly acetosyringone-inducible promoters of virb, virc, vird, and vire and the weakly inducible promoters of vira and virg. identical induction patterns were obtained with freshly sliced carrot disks, suggesting that an inducer is released after plant tissue is wounded. optimal conditions for vir ... | 1987 | 2822665 |
| physical analysis of pb2, a temperate bacteriophage of agrobacterium tumefaciens. | we have constructed a detailed physical map of pb2, a temperate bacteriophage of agrobacterium tumefaciens. the restriction endonucleases bam hi (3 sites), eco ri (22 sites), hind iii (19 sites), hpa i (5 sites), xba i (1 site), and xho i (1 site) were used to elucidate the map of infectious pb2 dna. the map was generated by reciprocal sequential digestions and analysis of partial digestion products of isolated restriction fragments. we have determined the genome size as 66.35 +/- 1.71 kb. the p ... | 1987 | 2824148 |
| similarities between nucleotide sequences of insertion elements of agrobacterium tumefaciens and pseudomonas savastanoi in relation to agrobacterium tumefaciens tc-dna. | 1987 | 2827126 | |
| genetic analysis of the gentamicin resistance region of pph1ji and incorporation into a wide host range cloning vehicle. | a region of the incp plasmid pph1ji encoding resistance to gentamicin, spectinomycin, and streptomycin was characterized by subcloning, deletion, and insertion mutagenesis. approximate locations of these resistance determinants were established. a 1.6-kb hindiii-sphi segment of this region expresses gentamicin resistance (gmr) in escherichia coli when inserted into various plasmid vectors; this dna segment encodes a polypeptide of 17.5 kda. incorporation of this fragment into an incp cloning veh ... | 1987 | 2827208 |
| 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 |
| studies on the introduction and mobility of the maize activator element in arabidopsis thaliana and daucus carota. | we have co-transformed carrot (daucus carota) and arabidopsis thaliana with an agrobacterium tumefaciens non-tumorigenic t-dna carrying the maize transposable element activator (ac) and an agrobacterium rhizogenes ri t-dna. we present evidence that the ac element transposes in transformed root or root-derived callus cultures of both species. we show that fertile plants can be regenerated from transformed, root-derived callus cultures of arabidopsis, demonstrating the utility of the ri plasmid fo ... | 1987 | 2832144 |
| genetic analysis of the vire operon of the agrobacterium ti plasmid ptia6. | the vire operon of the agrobacterium tumefaciens ti plasmid ptia6 encodes at least one trans-acting protein involved in the expression of virulence. two open reading frames designated vire1 and vire2 code for polypeptides of 7 and 60 kilodaltons (kda), respectively, that can be visualized after expression in escherichia coli minicells. to determine which vire sequences are required for virulence, a strain deleted for the entire locus [strain ke1(ptia6 delta e)] was constructed and tested for the ... | 1988 | 2832362 |
| virulence genes, borders, and overdrive generate single-stranded t-dna molecules from the a6 ti plasmid of agrobacterium tumefaciens. | agrobacterium tumefaciens transfers the t-dna portion of its ti plasmid to the nuclear genome of plant cells. upon cocultivation of a. tumefaciens a348 with regenerating tobacco leaf protoplasts, six distinct single-stranded t-dna molecules (t strands) were generated in addition to double-stranded t-dna border cleavages which we have previously reported (k. veluthambi, r.k. jayaswal, and s.b. gelvin, proc. natl. acad. sci. usa 84:1881-1885, 1987). the t region of an octopine-type ti plasmid has ... | 1988 | 2832367 |
| characterization and mapping of the agrocinopine-agrocin 84 locus on the nopaline ti plasmid ptic58. | overlapping segments of ptic58 inserted into cosmid vectors were used to characterize the agrocinopine-agrocin 84 locus from the nopaline/agrocinopine a and b agrobacterium tumefaciens strain c58. all of the clones conferring agrocin 84 sensitivity on agrobacteria also conferred uptake of agrocin 84 and agrocinopines a and b. transposon tn3-hoho1 insertion mutations of one such clone were generated that simultaneously abolished agrocin 84 sensitivity and transport of agrocinopines a and b and ag ... | 1988 | 2832379 |
| the agrobacterium tumefaciens vire2 gene product is a single-stranded-dna-binding protein that associates with t-dna. | agrobacterium tumefaciens transfers t-dna into the plant genome by a process mediated by ti plasmid-encoded vir genes. cleavage at t-dna border sequences by the vird endonuclease generates linear, single-stranded t-dna molecules. in the work described in this report, we used electrophoretic mobility shift assays to show that the purified vire2 gene product binds to single-stranded dna. vire2 protein associates with t-dna as shown by immunoprecipitation studies with vire2-specific antiserum. the ... | 1988 | 2836366 |
| analysis of the complete nucleotide sequence of the agrobacterium tumefaciens virb operon. | the complete nucleotide sequence of the virb locus, from the octopine ti plasmid of agrobacterium tumefaciens strain 15955, has been determined. in the large virb-operon (9600 nucleotides) we have identified eleven open reading frames, designated virb1 to virb11. from dna sequence analysis it is proposed that nearly all virb products, i.e. virb1 to virb9, are secreted or membrane associated proteins. interestingly, both a membrane protein (virb4) and a potential cytoplasmic protein (virb11) cont ... | 1988 | 2837739 |
| mini-mulac transposons with broad-host-range origins of conjugal transfer and replication designed for gene regulation studies in rhizobiaceae. | novel mini-mu derivatives were constructed, carrying a truncated laczya operon fused to the terminal 117 bp of the mu s-end, for the isolation of translational lac fusions by mini-mu-mediated insertion mutagenesis. different selectable markers (chloramphenicol resistance; gentamycin resistance) were introduced to allow selection for mini-mu insertions in different replicons and bacterial strains. a mini-mulac derivative carrying the site for conjugal transfer of plasmid rp4 (orit) and the origin ... | 1988 | 2838383 |
| opine utilization by agrobacterium spp.: octopine-type ti plasmids encode two pathways for mannopinic acid degradation. | octopine-type strains of agrobacterium tumefaciens degrade the opine mannopinic acid through a specific pathway which involves cleavage of the molecule at the c--n bond between the amino acid and the sugar moieties. mannose was identified as a product of the reaction. this pathway was inducible by mannopinic and agropinic acids, but not by mannopine or agropine, the two other mannityl opines. the transport system for this pathway appeared to be specific for mannopinic acid. a second, nonspecific ... | 1988 | 2838452 |
| regulation of the virc and vird promoters of ptic58 by the ros chromosomal mutation of agrobacterium tumefaciens. | the virc and vird operons of the virulence region of the ti plasmid are highly regulated, requiring a transcriptional regulator that is encoded by virg and is activated by the product of vira and plant phenolics such as acetosyringone. full expression of virc and vird of octopine and nopaline ti plasmids is also obtained by a mutation in the ros gene of the agrobacterium tumefaciens chromosome. s1-nuclease analysis, in vitro transcription, and dnase i protection experiments with a. tumefaciens r ... | 1988 | 2840554 |
| transcriptional regulation of the vira and virg genes of agrobacterium tumefaciens. | we have used transcriptional and translational fusions between various vir gene promoters and the lacz gene to study the regulation of vir genes. like other vir promoters, the vira promoter was induced by acetosyringone in a vira virg-dependent fashion. in addition to being induced by acetosyringone, the virg promoter was partially induced by acidic growth conditions and by starvation for inorganic phosphate. these two conditions appeared to act synergistically. the response to low ph and to pho ... | 1988 | 2842300 |
| mobilization and transfer of azospirillum lipoferum plasmid by the tn5-mob transposon into a plasmid-free agrobacterium tumefaciens strain. | azospirillum lipoferum 4b harbors five cryptic plasmids. several suicide plasmids were used to transfer tn5-mob to a. lipoferum 4b. tn5-mob insertion mutations of this strain could be obtained at frequencies of 10(-8)-10(-7) per recipient cell. one hundred tn5-mob a. lipoferum 4b mutants were used in bacterial matings with a plasmid-free agrobacterium tumefaciens recipient strain. this is the first report of mobilization, transfer, and replication of an azospirillum plasmid in agrobacterium tume ... | 1988 | 2852995 |
| [deletional and insertional analysis of the antitumorigenicity of the plasmid r388 in agrobacterium tumefaciens]. | the study of the plasmid r388 deletional derivatives has shown the antitumorigenicity determinant of the plasmid to be contained by the tra-operon. transposon tn5 has been used for selection of a number of insertional mutants having lost the antitumorigenic properties. the difference in the locations of tn5 inserts was found, all of the latter being localized within the tra-operon. the data obtained suggest the locus of the plasmid r388 responsible for its antitumorigenic properties to be locate ... | 1988 | 2855090 |
| identification of the product of an agrobacterium tumefaciens chromosomal virulence gene. | the chvb operon of agrobacterium tumefaciens is required for bacterial attachment to plant cells and for efficient crown gall tumor formation. as defined by the virulence phenotypes of mutants with transposon insertions mapping in the region, the operon was previously mapped to a 5-kilobase (kb) stretch of chromosomal dna. we report here that the operon is actually about 8.5 kb long and that it contains a 7-kb gene coding for a large membrane protein involved in the synthesis of cyclic beta-1,2- ... | 1988 | 2856522 |
| a nuclear gene encoding the beta subunit of the mitochondrial atp synthase in nicotiana plumbaginifolia. | the beta subunit of the mitochondrial atp synthase in nicotiana plumbaginifolia is encoded by two nuclear genes, atp2-1 and atp2-2, which are both expressed. the complete nucleotide sequence of atp2-1 has been determined. it contains eight introns ranging from 88 to 1453 bp. the last intron contains a putative insertion element (inp), of 812 bp bordered by 35-bp inverted repeats which share an 11-bp homology with agrobacterium tumefaciens t-dna borders. sequences homologous to inp are present in ... | 1985 | 2866954 |
| both positive and negative regulatory elements mediate expression of a photoregulated cab gene from nicotiana plumbaginifolia. | we have analyzed promoter regulatory elements from a photoregulated cab gene (cab-e) isolated from nicotiana plumbaginifolia. these studies have been performed by introducing chimeric gene constructs into tobacco cells via agrobacterium tumefaciens-mediated transformation. expression studies on the regenerated transgenic plants have allowed us to characterize three positive and one negative cis-acting elements that influence photoregulated expression of the cab-e gene. within the upstream sequen ... | 1988 | 2901343 |
| cooperative interaction of agrobacterium vire2 protein with single-stranded dna: implications for the t-dna transfer process. | induction of agrobacterium tumefaciens vir gene expression by wounded plant cells results in production of a free transferable single-stranded (ss) copy of t-dna, the t-strand. one of the vir proteins, the vire2 polypeptide, is a ssdna-binding protein. in the present work, interaction of nopaline-specific vire2 protein (mr 69,000) with ssdna was studied by using nitrocellulose filter binding, gel retardation, and electron microscopy techniques. the vire2 protein was found to bind to ssdna molecu ... | 1989 | 2919168 |
| role for [corrected] agrobacterium tumefaciens chva protein in export of beta-1,2-glucan. | functional chva and chvb genes are required for attachment of agrobacterium tumefaciens to plant cells, an early step in crown gall tumor formation. strains defective in these loci do not secrete normal amounts of cyclic beta-1,2-glucan. whereas chvb is required for beta-1,2-glucan synthesis, the role of chva in glucan synthesis or export has not been clearly defined. we found that cultures of chva mutants contained as much neutral beta-1,2-glucan in the cell pellets as did the wild type, with n ... | 1989 | 2921245 |
| a protein required for transcriptional regulation of agrobacterium virulence genes spans the cytoplasmic membrane. | the vira protein is one of two proteins required for transcriptional activation of agrobacterium tumefaciens virulence genes in response to phenolic compounds released by plants during infection. we describe two experimental approaches which indicate that this protein has a transmembrane topology. first, spheroplasts of escherichia coli or wild-type a. tumefaciens expressing the vira protein were treated with proteinase k to digest periplasmic proteins, and the remaining proteins were immunologi ... | 1989 | 2921246 |
| two chromosomal loci involved in production of exopolysaccharide in agrobacterium tumefaciens. | the chromosomal locus psca (exoc) of agrobacterium tumefaciens lba4301 has been cloned by complementation of the avirulent and exopolysaccharide (eps)-deficient mutant lba4301 psca. we have also identified a new locus, termed psda (polysaccharide depression) and located 16 kilobases from psca in the a. tumefaciens chromosome, that negatively affects eps production when it is present in more than one copy in a. tumefaciens lba4301. subcloning, transposon mutagenesis, and transcriptional analysis ... | 1989 | 2921249 |
| high levels of double-stranded transferred dna (t-dna) processing from an intact nopaline ti plasmid. | to obtain bacterial-mediated oncogenic transformation of plants, the transferred dna (t-dna) of the tumor-inducing (ti) plasmid of agrobacterium tumefaciens is transferred to its plant host cells during infection. the initial phases of transformation involve the processing of the t-dna in the bacterial cell after induction of the vir genes located on the ti plasmid. the kinetics and conditions of this processing were examined and upon induction with acetosyringone up to 40% of the left and right ... | 1989 | 2928322 |
| in vitro activity of a-56268 (te-031), a new macrolide antibiotic, compared with that of erythromycin and other antimicrobial agents. | a-56268 is a new macrolide antibiotic that resembles erythromycin in its spectrum of activity. a-56268 and erythromycin had identical activities against streptococcus pyogenes, group b, c, and g streptococci, and viridans group streptococci. erythromycin and a-56268 had similar activities against staphylococcus aureus, coagulase-negative staphylococci, and group d enterococci. like erythromycin, a-56268 was ineffective in inhibiting oxacillin-resistant s. aureus, oxacillin-resistant, coagulase-n ... | 1987 | 2955742 |
| inducible expression of cytokinin biosynthesis in agrobacterium tumefaciens by plant phenolics. | nopaline strains of agrobacterium tumefaciens contain a gene, tzs, that encodes a cytokinin biosynthetic prenyl transferase. the gene is located adjacent to the ti plasmid virulence region and is constitutively expressed at low levels. as a result, bacteria containing tzs secrete low levels of zeatin into the medium. we find zeatin secretion to be induced more than 100-fold by acetosyringone, one of a number of naturally occurring phenolics produced by plants in response to wounding. induction w ... | 1988 | 2980282 |
| identification and genetic analysis of an agrobacterium tumefaciens chromosomal virulence region. | a genetic analysis of agrobacterium tumefaciens chromosomal functions required for virulence was undertaken. large tn5-containing cosmid clones were isolated from dna of avirulent a. tumefaciens mutants having chromosomal tn5 insertions and exhibiting defective attachment to plant cells. the clones from several different mutants each contained overlapping segments of a 30-kilobase a. tumefaciens chromosomal region, which were physically mapped. all chromosomal tn5 insertions leading to the aviru ... | 1985 | 2982791 |
| identification of ptic58 plasmid-encoded proteins for virulence in agrobacterium tumefaciens. | analyses were made of the host-dependent-variation (hdv) locus of the virulence (vir) region of the ptic58 plasmid of agrobacterium tumefaciens. the hdv locus is comprised of at least four genes that encode polypeptides of 13, 15, 29, and 28 kda. insertion of transposon tn5 in the first gene abolishes the expression of all four genes in vitro and in vivo. nucleotide sequence analysis of the hdv locus revealed four open reading frames tandemly arranged with spacer sequences having no promoter-lik ... | 1985 | 2986128 |
| cloning and nucleotide sequence of the tzs gene from agrobacterium tumefaciens strain t37. | the trans-zeatin secretion locus (tzs), from the nopaline ti plasmid of agrobacterium tumefaciens strain t37, was cloned and the nucleotide sequence determined. this gene is located in the virulence region of ptit37. the tzs gene is responsible for the secretion of trans-zeatin into bacterial culture medium and in addition has the cytokinin biosynthetic activity, dimethylallylpyrophosphate:amp dimethylallyltransferase. sequence analysis showed an open reading frame of 729 nucleotides, capable of ... | 1985 | 2987868 |
| rhizobium meliloti carries two megaplasmids. | in rhizobium meliloti strain 41 the existence of a second megaplasmid (prme41c) with a molecular weight similar to the sym megaplasmid prme41b was demonstrated. derivatives of the wild-type strain carrying prme41b or prme41c tagged with tn5 allowed the examination of the transfer ability of both megaplasmids. the introduction of megaplasmids into the wild-type r. meliloti was not detected, probably because of the action of plasmid genes coding for entry exclusion of the same type of plasmid. how ... | 1985 | 2987992 |
| a tn3 lacz transposon for the random generation of beta-galactosidase gene fusions: application to the analysis of gene expression in agrobacterium. | the construction and use of a tn3-lac transposon, tn3-hoho1, is described. tn3-hoho1 can serve as a transposon mutagen and provides a new and useful system for the random generation of both transcriptional and translational lacz gene fusions. in these fusions the production of beta-galactosidase, the lacz gene product, is placed under the control of the gene into which tn3-hoho1 has inserted. the expression of the gene can thus be analyzed by monitoring beta-galactosidase activity. tn3-hoho1 car ... | 1985 | 2990912 |
| expression of a rhizobium phaseoli sym plasmid in r. trifolii and agrobacterium tumefaciens: incompatibility with a r. trifolii sym plasmid. | identification of the sym plasmid in rhizobium phaseoli strain rcc3622 is described. introduction of this plasmid into r. trifolii or agrobacterium tumefaciens strains resulted in bacteria capable of forming characteristic spherical root nodules on beans. this sym plasmid, designated psym9, was characterized as 275 mda and nonconjugative. psym9 was incompatible with the r. trifolii sym plasmid psym5, and carries genes determining a melanin-like black pigment. a second plasmid of 135 mda, prph362 ... | 1985 | 2994130 |
| mode of action of agrobacterium tumefaciens lipopolysaccharide (lps) in mice hepatic tissue: a comparative study with salmonella typhimurium lps. | 1985 | 2997027 | |
| positive selection procedure for entrapment of insertion sequence elements in gram-negative bacteria. | we constructed the broad-host-range plasmid pucd800 containing the sacb gene of bacillus subtilis for use in the positive selection and isolation of insertion sequence (is) elements in gram-negative bacteria. cells containing pucd800 do not grow on medium containing 5% sucrose unless the sacb gene is inactivated. by using pucd800, we isolated a 1.4-kilobase putative is element from agrobacterium tumefaciens nt1re by selection for growth on sucrose medium. this putative is element appears to be u ... | 1985 | 2997137 |
| nucleotide sequence analysis of tl-dna of agrobacterium rhizogenes agropine type plasmid. identification of open reading frames. | we have determined the nucleotide sequence of the ri tl-dna region from an agrobacterium rhizogenes agropine-type plasmid using subcloned regions from the essentially identical ri tl-dnas from strains a4 and hri. this sequenced region of 21,126 base pairs (bp) contains the complete tl-dna region of the ri plasmid as determined by analysis of tl-dna borders in the genome of infected, clonal, convolvulus arvensis plants. the left and right borders of the tl-dna are flanked by 25-bp sequences which ... | 1986 | 3001043 |
| stable transformation of maize after gene transfer by electroporation. | the graminaceous monocots, including the economically important cereals, seem to be refractory to infection by agrobacterium tumefaciens, a natural gene transfer system that has been successfully exploited for transferring foreign genes into higher plants. therefore, direct transfer techniques that are potentially applicable to all plant species have been developed using a few dicot and monocot species as model systems. one of these techniques, electroporation, uses electrical pulses of high fie ... | 1986 | 3005872 |
| expression of a bean storage protein 'phaseolin minigene' in foreign plant tissues. | using the phaseolin gene and its cdna counterpart we constructed a mutant phaseolin gene lacking the five introns but retaining its natural 5' and 3' plant-regulatory sequences. this mutant phaseolin gene (minigene) was inserted into the ti-plasmid of agrobacterium tumefaciens strain 15955 which allowed its transfer and integration into the tobacco genome. full-length and correctly initiated phaseolin mrna was found among the poly(a)+rna isolated from plant callus transformed with the minigene c ... | 1986 | 3009275 |
| activity of t-dna borders in plant cell transformation by mini-t plasmids. | by using a binary vector system, we examined the requirements for border sequences in t-dna transformation of plant genomes. mini-t plasmids consisting of small replicons with different extents of ptit37 t-dna were tested for plant tumor-inducing ability in agrobacterium tumefaciens strain lba4404 containing helper plasmid pal4404 (which encodes virulence genes needed for t-dna transfer). assays of these bacteria on carrot disks, kalanchoë leaves, and sr1 nicotiana tabacum plantlets showed that ... | 1986 | 3009403 |
| second symbiotic megaplasmid in rhizobium meliloti carrying exopolysaccharide and thiamine synthesis genes. | using physical and genetic data, we have demonstrated that rhizobium meliloti su47 has a symbiotic megaplasmid, prmesu47b, in addition to the previously described nod-nif megaplasmid prmesu47a. this plasmid includes four loci involved in exopolysaccharide (exo) synthesis as well as two loci involved in thiamine biosynthesis. mutations at the exo loci have previously been shown to result in the formation of nodules which lack infection threads (inf-) and fail to fix nitrogen (fix-). thus, both me ... | 1986 | 3013840 |
| the genetic and transcriptional organization of the vir region of the a6 ti plasmid of agrobacterium tumefaciens. | the genetic transformation of plant cells by agrobacterium tumefaciens is mediated by the genes of the ti plasmid vir region. to determine the genetic and transcriptional organization of the vir region of ptia6, vir plasmid clones were saturated with insertion mutations of a tn3-lacz transposon. this element is both an insertion mutagen and a reporter for the expression of the sequences into which it has inserted. one hundred and twenty-four vir::tn3-lac insertions were analyzed for their mutage ... | 1986 | 3017694 |
| nucleotide sequence of an insertion sequence (is) element identified in the t-dna region of a spontaneous variant of the ti-plasmid ptit37. | we have identified and determined the nucleotide sequence of an is element (is136) of agrobacterium tumefaciens. this is the first is element isolated and sequenced from a nopaline type ti-plasmid. our is element has 32/30 bp inverted repeats with 6 mismatches, is 1,313 bp long and generates 9 bp direct repeats upon integration. is136 has 3 main open reading frames (orf's). only orf1 (159 codons) is preceded by sequences that are proposed to serve functional roles in transcriptional and translat ... | 1986 | 3018677 |
| location of the right boundary of the virulence region on agrobacterium tumefaciens plasmid ptic58 and a host-specifying gene next to the boundary. | the right boundary of the virulence (vir) region of the nopaline plasmid ptic58 of agrobacterium tumefaciens was determined by transposon insertion, cartridge emplacement, and deletion mutagenesis. genetic complementation with mutant and wild-type alleles led to the identification of the vire locus at the right boundary, which was located about 6 kilobases from the left border of the segment of dna that is transferred into the plant genome. vire is 2.0 kilobases long and encodes at least one pro ... | 1986 | 3019998 |
| two-component regulatory systems responsive to environmental stimuli share strongly conserved domains with the nitrogen assimilation regulatory genes ntrb and ntrc. | we report that the ntrb and ntrc proteins of bradyrhizobium sp. [parasponia] strain rp501 share homology with other regulatory proteins. there is extensive conservation of c-terminal regions between products of rp501 ntrb; klebsiella pneumoniae ntrb; escherichia coli envz, cpxa, and phor; agrobacterium tumefaciens vira; and, to a lesser extent, e. coli chea. there is also extensive conservation of n-terminal regions between products of rp501 ntrc; k. pneumoniae ntrc; e. coli ompr, sfra, phob, ch ... | 1986 | 3020561 |
| the vird operon of agrobacterium tumefaciens encodes a site-specific endonuclease. | tumor formation by agrobacterium tumefaciens involves the transfer and integration of a defined segment (t-dna) of tumor-inducing (ti) plasmid dna into the plant nuclear genome. a set of plasmid genes outside the t-dna, the vir genes, are thought to mediate the transfer process. we report here that the vird operon encodes a site-specific endonuclease that cleaves at a unique site within each of the 24 bp direct repeats that flank the t-dna. the endonuclease function was further localized to the ... | 1986 | 3021341 |
| a gene essential for agrobacterium virulence is homologous to a family of positive regulatory loci. | the vir region of agrobacterium tumefaciens spans at least six transcriptional loci required for crown gall tumorigenesis. the transcriptional induction of two of these vir loci in response to cocultivation with tobacco suspension cells was measured by using bacteria containing mutations in each of the six vir loci located on the ti plasmid. induction of these vir genes occurred only in bacteria that had functional copies of vira and virg. the nucleic acid sequence of a 1.25-kilobase clone encom ... | 1986 | 3022288 |
| cloning and regulation of erwinia herbicola pigment genes. | the genes coding for yellow pigment production in erwinia herbicola eho10 (atcc 39368) were cloned and localized to a 12.4-kilobase (kb) chromosomal fragment. a 2.3-kb avai deletion in the cloned fragment resulted in the production of a pink-yellow pigment, a possible precursor of the yellow pigment. production of yellow pigment in both e. herbicola eho10 and pigmented escherichia coli clones was inhibited by glucose. when the pigment genes were transformed into a cya (adenylate cyclase) e. coli ... | 1986 | 3023282 |
| t-dna and opine synthetic loci in tumors incited by agrobacterium tumefaciens a281 on soybean and alfalfa plants. | we report here the molecular characterization of transferred dna (t-dna) in leguminous tumors incited by agrobacterium tumefaciens a281 harboring the tumor-inducing plasmid ptibo542. the t-dna is composed of two regions named tl (left portion)-dna and tr (right portion)-dna, in accordance with the nomenclature for the octopine strains. tl-dna is defined by several internal hindiii restriction fragments totaling 10.8 kilobase pairs (kbp) in uncloned soybean and alfalfa tumors. alfalfa tumor dna m ... | 1986 | 3023301 |
| biosynthesis and degradation of nodule-specific rhizobium loti compounds in lotus nodules. | two nodule-specific rhizobium loti compounds were identified in lotus tenuis and lotus pedunculatus nodules induced by strain nzp2037. one, a silver nitrate-positive cation called rhizolotine, has been characterized as the riboside of a novel alpha-hydroxyimino acid containing a 1,4,5,6-tetrahydropyrimidine ring (g. j. shaw, r. d. wilson, g. a. lane, l. d. kennedy, d. b. scott, and g. j. gainsford, j. chem. soc. chem. commun., p. 180-181, 1986), and the other, yellow-1, stains yellow with ninhyd ... | 1987 | 3025173 |
| characterization of nonattaching mutants of agrobacterium tumefaciens. | the first step in tumor formation by agrobacterium tumefaciens is the site-specific binding of the bacteria to plant host cells. transposon mutants of the bacteria which fail to attach to carrot suspension culture cells were isolated. these mutants showed no significant attachment to carrot cells with either microscopic or viable cell count assays of bacterial binding. the nonattaching mutants were all avirulent. when revertants of the mutants were obtained by enriching for bacteria which do bin ... | 1987 | 3025176 |
| [characteristics of derivatives of the plasmid rp4 in a broad range of hosts with altered properties of maintenance and inheritance]. | hydroxylamine-induced mutants of the plasmid ppd6 (8.4 kb) were isolated which are resistant to high doses of tetracycline. one of the plasmids studied--ppd21 is a multicopy mutant, another one, ppd12 is a dimeric form of the ppd6 plasmid. the ppd12 plasmid is very unstable, its derivative, ppd13 spontaneous mutant acquiring stability but not the ability to resolve dna multimeric forms into monomeric forms. multicopy bireplicon ppd619 plasmid was constructed by joining in vitro ppd6 and puc19 pl ... | 1986 | 3026896 |
| integration of the delta-endotoxin gene of bacillus thuringiensis into the chromosome of root-colonizing strains of pseudomonads using tn5. | the delta-endotoxin gene (tox) from bacillus thuringiensis subsp. kurstaki hd-1 was cloned into tn5 and the resulting tn5-tox element transposed from a vector plasmid into the chromosome of six corn-root-colonizing strains of pseudomonas fluorescens and agrobacterium radiobacter. chromosomal integration of the tox gene maximized stability and minimized the potential for horizontal transfer of the tox gene to other bacterial species. expression of the tox gene was demonstrated by western blot ana ... | 1986 | 3026918 |
| nucleotide sequence of the virulence gene virg of the agrobacterium tumefaciens octopine ti plasmid: significant homology between virg and the regulatory genes ompr, phob and dye of e. coli. | the entire nucleotide sequence of the virg locus, from the octopine ti plasmid of agrobacterium tumefaciens strain 15955, has been determined. the virg gene is 801 nucleotides in length and has one open reading frame which encodes a protein of mr 29,995. the virg gene is involved in the transcriptional activation of the ti plasmid vir-loci, which occurs after induction by specific compounds present in plant exudate. sequence analysis of the agrobacterium virg protein showed significant homology ... | 1986 | 3027669 |
| a spontaneous insertion in the agrocin sensitivity region of the ti-plasmid of agrobacterium tumefaciens c58. | a spontaneous agrocin-resistant mutant of agrobacterium tumefaciens strain c58 was shown to have an insertion of 1.2 kb in the agrocin-sensitivity region of ptic58. the insertion was cloned from the ti-plasmid, and a subclone containing only dna internal to the insertion was used to probe the ti-plasmid and chromosomal dna of the wild-type strain c58. the probe showed homology to chromosomal sequences but showed no homology to wild-type ptic58. homology was also detected with chromosomal sequenc ... | 1986 | 3027729 |
| studies of the structure and functional organization of foreign dna integrated into the genome of nicotiana tabacum. | in transgenic plants obtained either by agrobacterium tumefaciens-mediated transformation or by direct dna transfer, the structure of integrated chimeric donor dna remains stable during vegetative proliferation, during sexual transmission, and under various selection conditions. we correlate the level of expression of the introduced gene in independent transformants and their offspring with the particular arrangement and modification of their integrated dnas. genetic analysis of transgenic plant ... | 1986 | 3028737 |
| processing of the t-dna of agrobacterium tumefaciens generates border nicks and linear, single-stranded t-dna. | transfer and integration of a defined region (t-dna) of the tumor-inducing (ti) plasmid of agrobacterium tumefaciens is essential for tumor formation. we used a physical assay to study structural changes induced in agrobacterium t-dna by cocultivation with plant cells. we show that nicks are introduced at unique, identical locations in each of the 24-base-pair imperfect direct repeats which flank the t-dna and present evidence that a linear, single-stranded molecule is generated. we propose that ... | 1987 | 3029014 |
| transfer of drosophila melanogaster transponsable genetic element mdg-4 into plant cells. | the copia-like element mdg-4, as a component of the drosophila genomic fragment dm111, was cloned into the vector pib16. the chimaeric plasmid pib16 [dm111] was used to transform tobacco cells as a cointegrate with ptic58 (agrobacterium tumefaciens), ptic58::pib16 [dm111]. the growth properties of primary crown-gall tumours were followed, and the dna of one nicotiana tabacum transformant was further analysed. the dna/dna molecular hybridization of digests of genomic dna with 32p-labelled pdm111 ... | 1987 | 3032699 |
| interposon mutagenesis of soil and water bacteria: a family of dna fragments designed for in vitro insertional mutagenesis of gram-negative bacteria. | we have constructed a series of derivatives of the omega interposon [prentki and krisch, gene 29 (1984) 303-313] that can be used for in vitro insertional mutagenesis. each of these dna fragments carries a different antibiotic or hg2+ resistance gene (apr, cmr, tcr, kmr or hgr) which is flanked, in inverted orientation, by transcription and translation termination signals and by synthetic polylinkers. the dna of these interposons can be easily purified and then inserted, by in vitro ligation, in ... | 1987 | 3038679 |
| deletion analysis of the mannopine synthase gene promoter in sunflower crown gall tumors and agrobacterium tumefaciens. | we have used deletion mutagenesis to analyze a tr-dna promoter from the octopine-type ti plasmid ptib6806. the promoter for the gene encoding mannopine synthase (mas) was cloned upstream of the bacterial kanamycin-resistance gene neomycin phosphotransferase ii (npt ii). bal31 deletion mutagenesis was used to generate deletion derivatives of the mas/nptii gene beginning 1353 bp upstream of the initiation of transcription and extending to 120 bp downstream from the mrna start site. deletions that ... | 1987 | 3039293 |
| the noc region of ti plasmid c58 codes for arginase and ornithine cyclodeaminase. | plant tumors induced by agrobacterium tumefaciens synthesize a group of substances (opines) which can serve as sole source of carbon and nitrogen for the bacteria. we investigate ti-plasmid-coded genes and enzymes involved in catabolism of the opine n2-(1,3-dicarboxypropyl)-l-arginine (nopaline) with a novel approach: expression and mapping of protein-coding regions in escherichia coli minicells, followed by identification of enzyme functions in the heterologous e. coli background. the results s ... | 1987 | 3040404 |
| 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 |
| 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 | |
| specialized binary vector for plant transformation: expression of the arabidopsis thaliana ahas gene in nicotiana tabacum. | we constructed a cosmid vector, poca18, designed for transferring plant genomic libraries from agrobacterium tumefaciens to plants. clones from a genomic library of arabidopsis thaliana dna in poca 18 were propagated stably in both escherichia coli and a. tumefaciens. clones from the poca18 a. thaliana library were used to construct transgenic nicotiana tabacum plants; the dna inserts were transferred intact in 10 out of 16 transgenic n. tabacum plants examined but were partially deleted in six ... | 1988 | 3060849 |
| 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 |
| plant phenolic compounds induce expression of the agrobacterium tumefaciens loci needed for virulence. | the virulence loci of agrobacterium tumefaciens are a set of linked transcriptional units that play an essential role in the early stages of plant tumorigenesis. these loci are induced upon cocultivation of the bacteria with plant cells. seven phenolic compounds that are widely distributed among the angiosperm plants--catechol, gallic acid, pyrogallic acid, p-hydroxybenzoic acid, protocatechuic acid, beta-resorcylic acid, and vanillin--are able to induce the expression of the virulence loci. the ... | 1986 | 3085219 |
| klebsiella pneumoniae nif-lac fusions are expressed in agrobacterium tumefaciens c58. | plasmids containing hybrid genes, in which different klebsiella pneumoniae nif (nitrogen-fixation) promoters were fused with the structural part of the escherichia coli lac operon, were introduced into a double auxotrophic derivative of agrobacterium tumefaciens c58. a study of their expression in the new host was made simple by the inherent inability of a. tumefaciens c58 to produce beta-galactosidase unless provided with the wild-type lac operon of e. coli. as shown by quantitative measurement ... | 1987 | 3108628 |
| genetic analysis of mannityl opine catabolism in octopine-type agrobacterium tumefaciens strain 15955. | the genetic organization of functions responsible for mannityl opine catabolism of the ti plasmid of agrobacterium tumefaciens strain 1,5955 was investigated. a partial hindiii digest of pti1,5955 was cloned into a broad host range cosmid and the clones obtained were tested for ability to confer mannityl opine degradation upon agrobacterium. inserts containing genes for catabolism of mannopinic acid, mannopine, agropine, and agropinic acid were obtained, spanning a segment of 43 kb on the ti pla ... | 1987 | 3112522 |
| 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 |