| studies on the toxicity of agrobacterium tumefaciens in mice. | | 1988 | 3235104 |
| vird proteins of agrobacterium tumefaciens are required for the formation of a covalent dna--protein complex at the 5' terminus of t-strand molecules. | the t-dna transfer process of agrobacterium tumefaciens is activated by the induction of the ti plasmid virulence (vir) loci by plant signal molecules such as acetosyringone. upon initiation of the t-dna transfer process, site-specific nicks occur at the 25-bp border sequences. this cleavage leads to the generation of a free, linear sst-dna molecule which is bound by sequence non-specific vire proteins. here we present evidence for the involvement of other acetosyringone-induced proteins in the ... | 1988 | 3243272 |
| behaviour of expression of nif hdk and fix abcx promoters of rhizobium meliloti in r. leguminosarum. | | 1988 | 3243555 |
| transgenic plants: horizontal transfer of nifhd dna to tobacco. | | 1988 | 3255666 |
| a bacteriophage t4 expression cassette that functions efficiently in a wide range of gram-negative bacteria. | we have constructed a derivative of the broad-host-range vector rsf1010. this plasmid, p alpha omega, contains an expression cassette derived from bacteriophage t4 gene 32, into which we have inserted the coding sequence for the xyle enzyme (c2,3o) of the tol plasmid pwwo. the composite plasmid, p alpha xyle omega, was transferred by conjugal mobilisation into a variety of gram-negative bacteria (agrobacter, paracoccus, erwinia, pseudomonas, rhizobium and xanthomonas). high levels of c2,3o activ ... | 1988 | 3259198 |
| cloning and characterization of the 5-aminolevulinate synthase gene(s) from rhodobacter sphaeroides. | the 5-aminolevulinate synthase gene (hema) from rhizobium meliloti was used to probe a genomic lambda bank derived from rhodobacter sphaeroides dna. two phage clones were found to bear homology to the rhizobium probe. southern hybridization analysis of the two lambda phage clones, which we designated lambda hem 10 and lambda hem 12, showed that the homology to the rhizobium hema gene was localized to a 3.1-kb sali fragment derived from lambda hem 10 and a 7.0-kb sali fragment derived from lambda ... | 1988 | 3266489 |
| binding-protein-dependent glucose transport by agrobacterium radiobacter grown in glucose-limited continuous culture. | agrobacterium radiobacter ncib 11883 was grown in glucose-limited continuous culture at low dilution rate. whole cells transported glucose using an energy-dependent mechanism which exhibited an accumulation ratio greater than 2000. three major periplasmic proteins were purified and their potential role as glucose-binding proteins (gbp) were investigated using equilibrium dialysis. two of these, gbp1 (mr 36,500) and gbp2 (mr 33,500), bound d-glucose with high affinity (kd 0.23 and 0.07 microm res ... | 1988 | 3269386 |
| the relationship between glucose transport and the production of succinoglucan exopolysaccharide by agrobacterium radiobacter. | agrobacterium radiobacter ncib 11883 was grown in ammonia-limited continuous culture at low dilution rate with glucose as the carbon source. under these conditions the organism produced an extracellular succinoglucan polysaccharide and transported glucose using the same periplasmic glucose-binding proteins (gbp1 and gbp2) as during glucose-limited growth. transition from glucose- to ammonia-limited growth was accompanied by a very rapid decrease in glucose uptake capacity, whereas the glucose-bi ... | 1988 | 3269387 |
| ornithine cyclodeaminase from ti plasmid c58: dna sequence, enzyme properties and regulation of activity by arginine. | nopaline, an abundant opine in plant cells transformed with nopaline-type ti plasmids, is catabolized in agrobacterium by three ti-plasmid-coded steps via arginine and ornithine to proline. the last enzyme, ornithine cyclodeaminase (ocd), converts ornithine directly into proline with release of ammonia. we describe the dna sequence of the ocd gene from ti plasmid c58, antiserum against an ocd fusion protein overexpressed in escherichia coli, induction and identification of the gene product in ag ... | 1988 | 3281832 |
| characterization of the virb operon from an agrobacterium tumefaciens ti plasmid. | the virulence genes of the agrobacterium tumefaciens ti plasmid are grouped into six transcription units and direct the transfer of t-dna into plant cells. we report here the nucleotide sequence of the largest vir operon, virb, from the ti plasmid ptia6nc. this operon contains 11 open reading frames, 7 of which show evidence of translational coupling. trpe::virb gene fusions were used to confirm the reading frames of genes virb2, 4, 5, 6, 7, 8, 10, and 11. in addition, the native gene products o ... | 1988 | 3281947 |
| [transfer of hybrid plasmids prp1.2::mini-mu into agrobacterium and rhizobium cells]. | the study is devoted to determination of bacteriophage mu genome regions responsible for transfer limitation and instability of the plasmids in cells of strains of practically important microorganisms. with this aim in view, we determined the frequency of transfer into agrobacterium tumefaciens and rhizobium meliloti cells of plasmids with mini-mu phages carrying previously constructed deletions of various lengths. sharp decrease has been noted in the frequency of transfer into a. tumefaciens st ... | 1988 | 3288538 |
| specific binding of proteins from rhizobium meliloti cell-free extracts containing nodd to dna sequences upstream of inducible nodulation genes. | nodulation (nod) genes in rhizobium meliloti are transcriptionally induced by flavonoid signal molecules, such as luteolin, produced by its symbiotic host plant, alfalfa. this induction depends on expression of nodd. upstream of three inducible nod gene clusters, nodabc, nodfe, and nodh, is a highly conserved sequence referred to as a 'nod box.' the upstream sequences have no other obvious similarity. we have found that dna fragments containing the regions upstream of all three inducible transcr ... | 1988 | 3288541 |
| osmotic control of glycine betaine biosynthesis and degradation in rhizobium meliloti. | intracellular accumulation of glycine betaine has been shown to confer an enhanced level of osmotic stress tolerance in rhizobium meliloti. in this study, we used a physiological approach to investigate the mechanism by which glycine betaine is accumulated in osmotically stressed r. meliloti. results from growth experiments, 14c labeling of intermediates, and enzyme activity assays are presented. the results provide evidence for the pathway of biosynthesis and degradation of glycine betaine and ... | 1988 | 3290197 |
| minimal region necessary for autonomous replication of ptar. | the native 44-kilobase-pair plasmid ptar, discovered in a grapevine strain of agrobacterium tumefaciens, contains a single origin of dna replication confined to a 1.0-kilobase-pair region of the macromolecule. this region (ori) confers functions sufficient for replication in agrobacterium and rhizobium species but not in pseudomonas solanacearum, pseudomonas glumae, pseudomonas syringae pv. savastanoi, xanthomonas campestris pv. campestris, and escherichia coli. ori contains a repa gene that enc ... | 1988 | 3290199 |
| identification and characterization of two nitrogen fixation regulatory regions, nifa and nfrx, in azotobacter vinelandii and azotobacter chroococcum. | five tn5-induced nif- mutants of azotobacter vinelandii were characterized as regulatory mutants because they were restored to nif+ by the introduction of constitutively expressed nifa from klebsiella pneumoniae. the mutants fell into two different classes on the basis of hybridization to a rhizobium leguminosarum nifa gene probe and by complementation with cosmids isolated from plafri gene banks of a. vinelandii and azotobacter chroococcum. one mutant, mv3, was located in or near a nifa gene. t ... | 1988 | 3294559 |
| cyclic glucans produced by agrobacterium tumefaciens are substituted with sn-1-phosphoglycerol residues. | in a previous study (miller, k.j., kennedy, e.p. and reinhold, v.n. (1986) science 231, 48-51) it was reported that the biosynthesis of periplasmic cyclic beta-1,2-glucans by agrobacterium tumefaciens is strictly osmoregulated in a pattern closely similar to that found for the membrane-derived oligosaccharides of escherichia coli (kennedy, e.p. (1982) proc. natl. acad. sci. usa 79, 1092-1095). in addition to the well-characterized neutral cyclic glucan, the periplasmic glucans were found to cont ... | 1987 | 3297148 |
| complementation of a threonine dehydratase-deficient nicotiana plumbaginifolia mutant after agrobacterium tumefaciens-mediated transfer of the saccharomyces cerevisiae ilv1 gene. | the saccharomyces cerevisiae ilv1 gene, encoding threonine dehydratase (ec 4.2.1.16) was fused to the transferred dna nopaline synthase promoter and the 3' noncoding region of the octopine synthase gene. it was introduced, by agrobacterium tumefaciens-mediated gene transfer, into an isoleucine-requiring nicotiana plumbaginifolia auxotroph deficient in threonine dehydratase. functional complementation by the ilv1 gene product was demonstrated by the selection of several transformed lines on a med ... | 1987 | 3302681 |
| new questions in strobel case. | | 1987 | 3306915 |
| a set of positively regulated flagellar gene promoters in caulobacter crescentus with sequence homology to the nif gene promoters of klebsiella pneumoniae. | the study reported here describes nuclease s1 mapping of the in-vivo transcription start sites of transcription units i and iii of the hook gene cluster of caulobacter crescentus. we show that transcription units i and ii of this flagellar (fla) gene cluster, which have divergent promoters with transcription start sites separated by 218 nucleotides, are under positive transcriptional control by genes in transcription unit iii. the promoters of transcription units i, ii, and iii were compared wit ... | 1987 | 3309346 |
| the symbiotic nitrogen fixation regulatory operon (fixrnifa) of bradyrhizobium japonicum is expressed aerobically and is subject to a novel, nifa-independent type of activation. | the bradyrhizobium japonicum n2 fixation regulatory gene, nifa, was sequenced and its transcription start site determined. between the start of transcription and the nifa gene an open reading frame of 278 codons was found and named fixr. a deletion in fixr which allowed transcription into nifa resulted in a 50% reduced fix activity. the fixrnifa operon was expressed in soybean root nodules, in cultures grown anaerobically with nitrate as terminal electron acceptor, in microaerobic cultures, and ... | 1987 | 3313281 |
| lupin leghemoglobins during root nodule development. | two yellow lupin leghemoglobins, lb i and lb ii, were purified to homogeneity using the hplc technique for final separation. lb i and lb ii were identified by the n-terminal sequences and their reaction with antibodies against electrophoretically pure leghemoglobin. the third lb species was detected by the combined method of isoelectrofocusing and page of lb i. it seems that lb iii represents a posttranslational modification of lb i. developmental changes in lb multiple forms were examined using ... | 1987 | 3314293 |
| rhizobium meliloti nifn (fixf) gene is part of an operon regulated by a nifa-dependent promoter and codes for a polypeptide homologous to the nifk gene product. | an essential gene for symbiotic nitrogen fixation (fixf) is located near the common nodulation region of rhizobium meliloti. a dna fragment carrying fixf was characterized by hybridization with klebsiella pneumoniae nif dna and by nucleotide sequence analysis. the fixf gene was found to be related to k. pneumoniae nifn and was therefore renamed as the r. meliloti nifn gene. upstream of the nifn coding region a second open reading frame was identified coding for a putative polypeptide of 110 amin ... | 1987 | 3316182 |
| physiology, biochemistry, and genetics of the uptake hydrogenase in rhizobia. | | 1987 | 3318673 |
| evidence that dna involved in the expression of nodulation (nod) genes in rhizobium binds to the product of the regulatory gene nodd. | in rhizobium leguminosarum biovar viciae, the regulatory nodulation nodd gene has at least two functions. it constitutively represses its own transcription and in the presence of inducer flavonoid molecules, it activates the expression of two other nod gene transcriptional units, nodabcij and nodfe. upstream of noda and nodf is a conserved sequence, the nod box, which has been implicated in nodd-mediated transcriptional activation of these genes. dna fragments spanning the nod boxes that precede ... | 1987 | 3320955 |
| incompatibility between a rhizobium sym plasmid and a ri plasmid of agrobacterium. | the symbiotic plasmid of rhizobium trifolii g1008 was mobilized to other rhizobium strains and to agrobacterium using tn5-mob, a transposon that confers on a host replicon the ability to be mobilized in trans by rp4. incompatibility was observed between psymg1008 and the hairy-root-inducing plasmid pri1855. agarose gel electrophoresis revealed that pri1855 was eliminated as an autonomous element in the presence of psymg1008 and its absence was correlated with loss of the ability to induce hairy ... | 1987 | 3324125 |
| foreign gene expression in plant cells. | | 1987 | 3326039 |
| [introduction and expression of foreign genes into plant cells using a ti plasmid vector]. | | 1987 | 3334467 |
| all nod genes of rhizobium meliloti are involved in alfalfa nodulation by exo mutants. | nodulation of alfalfa by exob mutants of rhizobium meliloti occurred without root hair curling or infection thread formation. nod exob double mutants had the same nodulation deficiency as single nod mutants. therefore, all the known nod genes are involved in nodule induction by exob mutants, which apparently occurs via intercellular invasion. | 1988 | 3338972 |
| root nodule specific gene regulation: analysis of the soybean nodulin n23 gene promoter in heterologous symbiotic systems. | the nodulin n23 gene promoter was analysed in transgenic plants using the chloramphenicol acetyltransferase (cat) coding sequence as a reporter. a 5' flanking region of less than 1 kb was sufficient for the organ-specific expression of a chimeric n23-cat-3'lbc3 gene in root nodules formed on lotus corniculatus and trifolium repens after infection by their respective rhizobium symbionts. expression was regulated at the level of rna in both species of transgenic plants. promoter deletion analysis ... | 1988 | 3340542 |
| agrobacterium-mediated infectivity of cloned digitaria streak virus dna. | a monomeric clone of double-stranded dna synthesized in vitro dna of the geminivirus digitaria streak (dsv) was subcloned as a tandem dimeric unit into a binary vector of agrobacterium tumefaciens, creating a plasmid pds2. inoculation of digitaria sanguinalis with a. tumefaciens carrying pds2 resulted in viral infection. the symptoms, virus particles, and dna forms obtained were indistinguishable from those of a natural dsv infection of d. sanguinalis. inoculations have also induced infections i ... | 1988 | 3341112 |
| genomic instability in rhizobium phaseoli. | experience from different laboratories indicates that rhizobium strains can generate variability in regard to some phenotypic characteristics such as colony morphology or symbiotic properties. on the other hand, several reports suggest that under certain stress conditions or genetic manipulations rhizobium cells can present genomic rearrangements. in search of frequent genomic rearrangements, we analyzed three rhizobium strains under laboratory conditions that are not considered to cause stress ... | 1988 | 3343217 |
| the complete structure of the trifoliin a lectin-binding capsular polysaccharide of rhizobium trifolii 843. | the complete structure of the acidic, extracellular, capsular polysaccharide of rhizobium trifolii 843 has been elucidated by a combination of chemical, enzymic, and spectroscopic methods, confirming an earlier proposed sugar sequence and assigning the locations of the acyl substituents. the polysaccharide was depolymerized by a lyase into octasaccharide units which were uniform in carbohydrate composition and linkage. these units also contained a uniform distribution of acetyl and pyruvic aceta ... | 1988 | 3349503 |
| a case of septicaemia caused by agrobacterium radiobacter. | | 1988 | 3351321 |
| proline metabolism in n2-fixing root nodules: energy transfer and regulation of purine synthesis. | n2-fixing root nodules of soybean (glycine max l. merr.) convert atmospheric n2 to ammonia(um) in an energy-intensive enzymatic reaction. these nodules synthesize large quantities of purines because nitrogen fixed by bacteria contained within this tissue is transferred to the shoots in the form of ureides, which are degradation products of purines. in animal systems, it has been proposed that proline biosynthesis by pyrroline-5-carboxylate reductase (p5cr) is used to generate the nadp+ required ... | 1988 | 3353366 |
| essential and non-essential domains in the bradyrhizobium japonicum nifa protein: identification of indispensable cysteine residues potentially involved in redox reactivity and/or metal binding. | the amino acid sequence of the bradyrhizobium japonicum nitrogen fixation regulatory protein nifa, as derived from the nucleotide sequence of the nifa gene, was aligned to the corresponding protein sequences from klebsiella pneumoniae, rhizobium meliloti and rhizobium leguminosarum biovar viciae. high conservation was found in the central domain and in the cooh-terminal, putative dna binding domain, whereas very little homology was present within the first 250 amino acids from the nh2-terminus. ... | 1988 | 3357773 |
| structure of the octopine synthase upstream activator sequence. | we have identified a transcriptional activating element within the 5' flanking sequence of the agrobacterium tumefaciens octopine synthase (ocs) gene that is necessary for ocs expression in transformed tobacco calli. this element is located between 333 and 116 base pairs upstream from the transcription initiation site and functions independent of orientation when placed upstream of the ocs gene. it does not function in either orientation when placed downstream of the gene, nor can it activate it ... | 1988 | 3357881 |
| scanning electron microscope studies of agrobacterium tumefaciens attachment to zea mays, gladiolus sp., and triticum aestivum. | scanning electron microscope studies demonstrated that cells of agrobacterium tumefaciens strains attach to cells on the cut surfaces of corn and wheat seedlings and to gladiolus disks. bacterial cells attached to these monocots in the same manner as they attached to the dicots tested. of the strains tested, a66 and t37 covered more of the cut surfaces of these monocots in a nonrandom fashion than did cells of other isolates. these bacteria attached to cells of intact monocotyledonous plants and ... | 1988 | 3360748 |
| cloning and characterization of a gene from rhizobium melilotii 2011 coding for ribosomal protein s1. | a 7 kb chromosomal dna fragment from r. melilotii was cloned, which complemented temperature-sensitivity of an e. coli amber mutant in rpsa, the gene for ribosomal protein s1 (es1). from complementation and maxicell analysis a 58 kd protein was identified as the homolog of protein s1 (rs1). dna sequence analysis of the r. melilotii rpsa gene identified a protein of 568 amino acids, which showed 47% identical amino acid homology to protein s1 from e. coli. the rs1 protein lacked the two cys resid ... | 1988 | 3368316 |
| lectin-enhanced accumulation of manganese-limited rhizobium leguminosarum cells on pea root hair tips. | the ability of rhizobium leguminosarum 248 to attach to developing pisum sativum root hairs was investigated during various phases of bacterial growth in yeast extract-mannitol medium. direct cell counting revealed that growth of the rhizobia transiently stopped three successive times during batch culture in yeast extract-mannitol medium. these interruptions of growth, as well as the simultaneous autoagglutination of the bacteria, appeared to be caused by manganese limitation. rhizobia harvested ... | 1988 | 3384802 |
| chemotaxis of rhizobium meliloti to the plant flavone luteolin requires functional nodulation genes. | luteolin is a phenolic compound from plants that acts as a potent and specific inducer of nodabc gene expression in rhizobium meliloti. we have found that r. meliloti rcr2011 exhibits positive chemotaxis towards luteolin. a maximum chemotactic response was observed at 10(-8) m. two closely related flavonoids, naringenin and apigenin, were not chemoattractants. the presence of naringenin but not apigenin abolished chemotaxis of r. meliloti towards luteolin. a large deletion in the nif-nod region ... | 1988 | 3384804 |
| physiology of behavioral mutants of rhizobium meliloti: evidence for a dual chemotaxis pathway. | wild-type and nonchemotactic mutant strains of rhizobium meliloti were tested for attraction to localized sites on alfalfa roots and for attraction to numerous small molecules, including sugars, amino acids, and two fractions derived from alfalfa root extracts. four strains (carrying mutations che-6, che-11, che-12, and che-26) lost all responses and were classified as generally nonchemotactic mutants. one strain (carrying mutation che-7) lost responses to a group of structurally unrelated amino ... | 1988 | 3384809 |
| vira and virg are the ti-plasmid functions required for chemotaxis of agrobacterium tumefaciens towards acetosyringone. | octopine and nopaline ti-plasmids confer upon agrobacterium tumefaciens c58c1 the ability to respond chemotactically to the vir-inducing phenolic wound exudate, acetosyringone. a. tumefaciens c58c1 containing ti-plasmids with tn5 insertions in virb, c, d or e exhibited marked chemotaxis towards acetosyringone. however, ti-plasmids with mutations in vira or virg were unable to confer the responsive phenotype. of the cosmid clones pvk219 (virab) pvk221 (virbgc) pvk225 (virgcde) and pvk257 (virabgc ... | 1988 | 3398775 |
| a core oligosaccharide component from the lipopolysaccharide of rhizobium trifolii anu843. | the major oligosaccharide from the core region of the lipopolysaccharide from r. trifolii anu843 was isolated and its structure determined. it is a trisaccharide consisting of two galacturonic acid residues and one 3-deoxy-d-manno-2-octulosonic acid (kdo) residue. the two galacturonic acid residues are terminally linked alpha to the c-4 and c-7 atoms of kdo. this structure was determined through use of 1h- and 13c-n.m.r. spectroscopy, f.a.b.-m.s., and g.l.c.-m.s. techniques. this oligosaccharide ... | 1988 | 3401882 |
| amino acid sequences of hemoglobins i and ii from root nodules of the non-leguminous parasponia rigida-rhizobium symbiosis, and a correction of the sequence of hemoglobin i from parasponia andersonii. | the amino acid sequence of hemoglobins i (pi 6.15 as oxyhemoglobin) and ii (pi 5.64 as oxyhemoglobin) from the nitrogen-fixing root nodules of parasponia rigida have been determined by protein sequencing. the sequence of hemoglobin i (pi 6.16, as oxyhemoglobin) from parasponia andersonii was re-examined and the corrected primary structure, now in agreement with that predicted from the dna sequence, is reported. the three parasponia hemoglobins contain 161 amino acid residues (mr approximately eq ... | 1988 | 3402445 |
| characterization of polysaccharides of rhizobium meliloti exo mutants that form ineffective nodules. | mutants of rhizobium meliloti su47 with defects in the production of the calcofluor-binding expolysaccharide succinoglycan failed to gain entry into alfalfa root nodules. in order to define better the polysaccharide phenotypes of these exo mutants, we analyzed the periplasmic oligosaccharide cyclic (1-2)-beta-d-glucan and lipopolysaccharide (lps) in representative mutants. the exoc mutant lacked the glucan and had abnormal lps which appeared to lack a substantial portion of the o side chain. the ... | 1988 | 3403505 |
| association of the vird2 protein with the 5' end of t strands in agrobacterium tumefaciens. | the soil bacterium agrobacterium tumefaciens can incite tumors in many dicotyledonous plants by transferring a portion (t-dna) of its ti plasmid into susceptible plant cells. the t-dna is flanked by border sequences that serve as recognition sites for specific cleavage by an endonuclease that comprises two vird-encoded proteins (vird1 and vird2). after cleavage, both double-stranded, nicked t-dna molecules and single-stranded t-dna molecules (t strands) were present. we have determined that a pr ... | 1988 | 3403506 |
| recognition of individual strains of fast-growing rhizobia by using profiles of membrane proteins and lipopolysaccharides. | membrane protein and lipopolysaccharide profiles of rhizobium leguminosarum (biovars viciae, trifolii, and phaseoli), r. meliloti, and agrobacterium tumefaciens strains were analyzed and compared by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. differences in one or both profiles allowed us to distinguish all 18 r. leguminosarum strains tested in this study from each other. | 1988 | 3403513 |
| induction of nitrogen-fixing nodules on clover requires only 32 kilobase pairs of dna from the rhizobium trifolii symbiosis plasmid. | overlapping subclones from the rhizobium trifolii symbiosis plasmid prt843a were generated by using in vivo and in vitro methods. subclones were assayed for symbiotic phenotype by introducing them into a derivative of r. trifolii anu843 cured of its symbiosis plasmid and testing the transconjugant strains for the ability to induce nitrogen-fixing nodules on clover. one subclone spanning 32 kilobase pairs (kb) of dna from prt843a was found to restore nitrogen fixation ability. this subclone inclu ... | 1988 | 3410817 |
| ti plasmid-specified chemotaxis of agrobacterium tumefaciens c58c1 toward vir-inducing phenolic compounds and soluble factors from monocotyledonous and dicotyledonous plants. | twelve phenolic compounds with related structures were analyzed for their ability to act as chemoattractants for agrobacterium tumefaciens c58c1 and as inducers of the ti plasmid virulence operons. the results divided the phenolic compounds into three groups: compounds that act as strong vir inducers and are chemoattractants for a. tumefaciens c58c1 harboring the nopaline ti plasmid pdub1003 delta 31, but not the isogenic cured strain; compounds that are at best weak vir inducers and are weak ch ... | 1988 | 3410827 |
| detection and subcellular localization of two sym plasmid-dependent proteins of rhizobium leguminosarum biovar viciae. | the previously described sym plasmid-dependent 24-kilodalton rhi protein of rhizobium leguminosarum biovar viciae was localized in the cytosol fraction. another sym plasmid-dependent protein of 50 kilodaltons is secreted into the growth medium, and its expression is dependent on both the nodd gene and a nod gene inducer. | 1988 | 3410833 |
| right-hand border regions of octopine t-dna are recognized by rna polymerase of agrobacterium as well as by vird1 and vird2 proteins. | the t-dna of octopine ti plasmid of agrobacterium tumefaciens contains tl- and tr-dna regions each bounded by 25 base-pair-repeats (designated a, b, c and d from left to right). short dna segments containing the borders b, c and d were found to function as promoter when placed in the rightward orientation upstream of promoter-less lacz. promoter consensus sequence of agrobacterium were found within these border repeats and in their adjacent regions. the expression of lacz was low when the segmen ... | 1988 | 3412897 |
| a large family of bacterial activator proteins. | at least nine different bacterial proteins belong to the lysr family. the gene sequence for one of these proteins is presented here. six others (escherichia coli lysr, ilvy, cysb; salmonella typhimurium metr; rhizobium nodd; and enterobacter cloacae ampr) are known to activate other genes. based on sequence alignments, each member of this family is predicted to have a helix-turn-helix dna binding motif near its amino terminus. the combined evidence indicates that all nine proteins are related by ... | 1988 | 3413113 |
| expression of nodule-specific genes in alfalfa root nodules blocked at an early stage of development. | to help dissect the molecular basis of the rhizobium-legume symbiosis, we used in vitro translation and northern blot analysis of nodule rna to examine alfalfa-specific genes (nodulins) expressed in two types of developmentally defective root nodules elicited by rhizobium meliloti. fix- nodules were elicited by r. meliloti nif mutants; these nodules were invaded by rhizobia and contained differentiated bacteroids. 'empty' nodules were elicited by r. meliloti exo and ndv mutants and by agrobacter ... | 1988 | 3417147 |
| identification of nodx, a gene that allows rhizobium leguminosarum biovar viciae strain tom to nodulate afghanistan peas. | gene(s) conferring the ability of rhizobium leguminosarum biovar viciae strain tom to nodulate primitive peas (cultivar afghanistan) had been located in a 2.0 kb region of its sym plasmid, prl5ji. in this dna, a single open reading frame of 1101 bp, corresponding to a gene, nodx was found. nodx is downstream of nodj which is present in strain tom and also in the sym plasmid of a typical strain of this biovar. nodx specifies a hydrophobic protein (of mr 41,036) with no clear similarity to other p ... | 1988 | 3419422 |
| vir box sequences in agrobacterium tumefaciens ptic58 and a6. | | 1988 | 3419938 |
| dicarboxylic acid transport in bradyrhizobium japonicum: use of rhizobium meliloti dct gene(s) to enhance nitrogen fixation. | a recombinant plasmid encoding rhizobium meliloti sequences involved in dicarboxylic acid transport (plasmid prk290:4:46) (e. bolton, b. higgisson, a. harrington, and f. o'gara, arch. microbiol. 144:142-146, 1986) was used to study the relationship between dicarboxylic acid transport and nitrogen fixation in bradyrhizobium japonicum. the expression of the dct sequences on plasmid prk290:4:46 in b. japonicum cj1 resulted in increased growth rates in media containing dicarboxylic acids as the sole ... | 1988 | 3422072 |
| characterization of agrobacterium tumefaciens virulence proteins induced by the plant factor acetosyringone. | the ti plasmid virulence (vir) loci encode functions essential for the transfer of the t-dna element from agrobacterium tumefaciens to plant cells. the expression of these loci is specifically signaled by plant phenolics such as acetosyringone. here, we characterize the protein products that are induced in agrobacterium grown in the presence of acetosyringone. more than 10 to 15 proteins are induced in strains harboring different ti plasmids. two general classes of acetosyringone-induced protein ... | 1987 | 3430596 |
| design and construction of a versatile system for the expression of foreign genes in plants. | we have built a series of vectors to allow the constitutive or light-regulated expression of foreign genes in plants. these vectors carry expression cassettes consisting of either the cauliflower mosaic virus 35s promoter or the pea rbcs-e9 promoter, a multiple cloning site derived from m13um20, and the rbcs-e9 polyadenylation site. these cassettes have been incorporated into pbr322-based or rk2-based replicons to facilitate direct dna uptake or agrobacterium tumefaciens-mediated gene transfer. ... | 1987 | 3443303 |
| deproteinized leaf juice as a medium for growth of rhizobium. | | 1987 | 3446598 |
| a study of predominant aerobic microflora of black bears (ursus americanus) and grizzly bears (ursus arctos) in northwestern alberta. | swab specimens were obtained from nasal, rectal, and preputial or vaginal areas of 37 grizzly and 17 black bears, captured during may to june of 1981 to 1983, to determine the types and frequency of predominant aerobic microflora. bacterial genera most frequently isolated from bears were escherichia, citrobacter, hafnia, proteus, staphylococcus, and streptococcus species, comprising about 65% of the isolates. erwinia, xanthomonas, agrobacterium, rhizobium, and gluconobacter/acetobacter were also ... | 1987 | 3447691 |
| nucleotide sequence of the virg locus of the agrobacterium tumefaciens plasmid ptic58. | the nucleotide sequence of the virg locus of the nopaline type plasmid ptic58 of agrobacterium tumefaciens has been determined. it contains an open reading frame (orf) of 759 nucleotides and has 77% homology to the virg sequences of octopine type plasmids. differences between the sequences of the two types of ti plasmids in the region of virg are located predominantly outside the orf. the amino acid sequences inferred from the two virg genes show 80% homology to each other and each shows the sam ... | 1987 | 3448462 |
| reiterated dna sequences in rhizobium and agrobacterium spp. | repeated dna sequences are a general characteristic of eucaryotic genomes. although several examples of dna reiteration have been found in procaryotic organisms, only in the case of the archaebacteria halobacterium halobium and halobacterium volcanii [c. sapienza and w. f. doolittle, nature (london) 295:384-389, 1982], has dna reiteration been reported as a common genomic feature. the genomes of two rhizobium phaseoli strains, one rhizobium meliloti strain, and one agrobacterium tumefaciens stra ... | 1987 | 3450286 |
| interaction between gram varieties and rhizobium isolates in relation to nodulation, plant growth and grain yield. | | 1987 | 3450684 |
| delay of disease development in transgenic plants that express the tobacco mosaic virus coat protein gene. | a chimeric gene containing a cloned cdna of the coat protein (cp) gene of tobacco mosaic virus (tmv) was introduced into tobacco cells on a ti plasmid of agrobacterium tumefaciens from which tumor inducing genes had been removed. plants regenerated from transformed cells expressed tmv mrna and cp as a nuclear trait. seedlings from self-fertilized transgenic plants were inoculated with tmv and observed for development of disease symptoms. the seedlings that expressed the cp gene were delayed in s ... | 1986 | 3457472 |
| analysis of agrobacterium tumefaciens virulence mutants in leaf discs. | the leaf disc transformation system provides a simple means to score expression of various t-dna markers within days of infection by agrobacterium tumefaciens as well as long-term selection for growth of transformed callus and shoots. in this report, we describe the application of this system to evaluation of marker transfer and integration in a comprehensive set of defined avirulent mutants of a. tumefaciens. we conclude that virc is not essential when the t-dna is present on a binary vector. t ... | 1986 | 3458219 |
| the right border region of ptit37 t-dna is intrinsically more active than the left border region in promoting t-dna transformation. | deletions of border regions of t-dna on agrobacterium ti plasmid or mini-t plasmid have shown the right border region of ptit37 t-dna to be more active than the left border region in promoting t-dna transformation. in this study we examine the possibility that the apparent difference in activity of left and right border regions may be due to position or orientation differences between the left and right borders with respect to the transferred onc genes. we have constructed eight similar single-b ... | 1986 | 3459162 |
| the promoter proximal region in the vird locus of agrobacterium tumefaciens is necessary for the plant-inducible circularization of t-dna. | the formation of crown gall tumours involves the transfer of the t-dna region of the ti plasmid from agrobacterium to plant cells and its subsequent integration into plant chromosomes. when agrobacteria are incubated with plant protoplasts or exudates of plants, the t-dna region is circularized by recombination or cleavage and rejoining between the 25 bp terminal repeats; the formation of circular t-dnas is thought to be one step in t-dna transfer (koukolikova-nicola et al. 1985; machida et al. ... | 1987 | 3472033 |
| overlapping transcription of the nifa regulatory gene in rhizobium meliloti. | gene fusions were used to demonstrate complex overlapping transcriptional controls of the regulatory gene nifa in rhizobium meliloti bacteroids isolated from alfalfa root nodules. gene nifa has previously been shown to be transcribed from promoter pnifa and to be required for activation of promoters p1 (nifhdk) and p2 (fixabc) during symbiotic nitrogen fixation with alfalfa. p2 is located approximately 4 kb upstream from nifa and is shown in this report to be responsible for at least one-half of ... | 1986 | 3472992 |
| sequence of psi, a gene on the symbiotic plasmid of rhizobium phaseoli which inhibits exopolysaccharide synthesis and nodulation and demonstration that its transcription is inhibited by psr, another gene on the symbiotic plasmid. | a gene termed psi (polysaccharide inhibition), located close to the nodulation genes of the rhizobium phaseoli symbiotic plasmid prp2ji inhibited exopolysaccharide synthesis (eps) and nodulation ability (nod) in rhizobium when it was cloned in a multicopy plasmid. the sequence of psi showed that it specified a polypeptide of mol. wt. 10,000 that may be associated with the membrane of rhizobium. a second gene, psr (polysaccharide restoration), was located on prp2ji. when cloned in multicopy plasm ... | 1987 | 3474492 |
| identification of two classes of rhizobium phaseoli genes required for melanin synthesis, one of which is required for nitrogen fixation and activates the transcription of the other. | the symbiotic plasmid prp2ji of rhizobium phaseoli strain 8002 was shown to contain two separate regions of dna which are required and sufficient for the synthesis of the pigment melanin. one of these regions containing the class ii mel gene(s) was located to other genes involved in nodulation and in nitrogen fixation. mutations in this region abolished both the ability to synthesize melanin and to fix nitrogen in phaseolus bean root nodules. mutations in the other, unlinked region, containing c ... | 1987 | 3474493 |
| high meiotic stability of a foreign gene introduced into tobacco by agrobacterium-mediated transformation. | two lines of transgenic nicotiana tabacum transformed to kanamycin resistance by means of a binary agrobacterium vector containing a nos-npt gene were investigated over three generations. southern hybridization and crossing analyses revealed that a single copy of t-dna had integrated in each line and that the kanamycin resistance was regularly transmitted to the progeny as a monogenic dominant trait. homozygous transgenic plants were fully fertile, morphologically normal and did not significantl ... | 1987 | 3474494 |
| west german release of altered bacteria causes furore. | | 1987 | 3475577 |
| rhizobium meliloti has three functional copies of the nodd symbiotic regulatory gene. | we have identified two rhizobium meliloti genes (nodd2 and nodd3) that are highly homologous and closely linked to the regulatory gene nodd (nodd1). r. meliloti strains containing mutations in the three nodd genes in all possible combinations were constructed and their nodulation phenotypes were assayed on medicago sativa (alfalfa) and melilotus alba (sweet clover). a triple nodd1-nodd2-nodd3 mutant exhibited a nod- phenotype on alfalfa and sweet clover, indicating that nodd is an essential nodu ... | 1987 | 3479806 |
| mobilization of t-dna from agrobacterium to plant cells involves a protein that binds single-stranded dna. | crude protein extracts of induced and uninduced octopine wild-type strain of agrobacterium tumefaciens, as well as several mutants of the virulence loci vira, -b, -g, -c, -d, and -e, were probed with single- and double-stranded synthetic oligodeoxynucleotides of different sequence and length in an electrophoretic retardation assay. four complexes involving sequence-nonspecific, single-stranded-dna-binding proteins were recognized. one inducible complex is determined by the vire locus, two ti-pla ... | 1987 | 3480525 |
| the nucleotide sequence of the sigma factor gene ntra (rpon) of azotobacter vinelandii: analysis of conserved sequences in ntra proteins. | the nucleotide sequence of the azotobacter vinelandii ntra gene has been determined. it encodes a 56916 dalton acidic polypeptide (avntra) with substantial homology to ntra from klebsiella pneumoniae (kpntra) and rhizobium meliloti (rmntra). ntra has been shown to act as a novel rna polymerase sigma factor but the predicted sequence of avntra substantiates our previous analysis of kpntra in showing no substantial homology to other known sigma factors. alignment of the predicted amino acid sequen ... | 1987 | 3481423 |
| immunological homology between the membrane-bound uptake hydrogenases of rhizobium japonicum and escherichia coli. | two polypeptides present in aerobic and anaerobic cultures of escherichia coli hb101 were shown to cross-react with antibodies to the 30- and 60-kilodalton (kda) subunits of the uptake hydrogenase of rhizobium japonicum. the cross-reactive polypeptides in a series of different e. coli strains are of mrs ca. 60,000 and 30,000, and both polypeptides are present in proportion to measurable hydrogen uptake (hup) activity (r = 0.95). the 60-kda polypeptide from e. coli hb101 comigrated on native gels ... | 1986 | 3511036 |
| molecular basis for the auxin-independent phenotype of crown gall tumor tissues. | the transfer of specific ti (tumor-inducing) plasmid sequences, the t-dna, from agrobacterium tumefaciens to a wide range of plants results in the formation of crown gall tumors. these tissues differ from most plant cells in that they can be grown in vitro in the absence of added phytohormones. here, data are presented that offer an explanation for the auxin-independent phenotype of crown gall tissues. it is shown that crude cell-free extracts prepared from three bacterial species harboring ptia ... | 1986 | 3511528 |
| promoters of agrobacterium tumefaciens ti-plasmid virulence genes. | the dna sequences of the promoter and 5' upstream regions of six agrobacterium tumefaciens ti-plasmid encoded virulence (vir) genes were determined. the transcription initiation sites were mapped by the s1 nuclease protection assay. in the -10 region, the vir promoters share a consensus sequence that is homologous to a dna sequence found in the same region of e. coli promoters. in contrast, the -35 region sequences are variable. several vir genes contain two common hexanucleotide sequences, 5'cg ... | 1986 | 3513123 |
| nucleotide sequence and expression of a pseudomonas savastanoi cytokinin biosynthetic gene: homology with agrobacterium tumefaciens tmr and tzs loci. | the nucleotide sequence of a pseudomonas trans-zeatin producing gene (ptz) from the pck1 plasmid of pseudomonas syringae pv. savastanoi strain 1006 has been determined. this gene confers upon e. coli the ability to synthesize and secrete several cytokinins including trans-zeatin, iso-pentenyladenine and their respective n9-ribosyl derivatives. sequence analysis indicates an open reading frame encoding a protein of 234 amino acids with a molecular weight of 26,816. significant sequence homology i ... | 1986 | 3515320 |
| expression and regulation of the escherichia coli glutamate dehydrogenase gene (gdh) in rhizobium japonicum. | the glutamate dehydrogenase (gdh) gene of escherichia coli was transferred into an ammonium assimilation deficient mutant (asm-) of rhizobium japonicum (cj9) using plasmid prp301, a broad host range derivative of rp4. exconjugants capable of growth on ammonia as sole n-source occurred at a frequency of 6.8 x 10(-6). assimilatory gdh (nadp+) activity was detected in the strain carrying the e. coli gdh gene and the pattern of ammonia assimilation via gdh was similar to that of the asm+ wild type s ... | 1986 | 3516109 |
| critical evaluation of the automicrobic system gram-negative identification card for identification of glucose-nonfermenting gram-negative rods. | during a 6-month study we critically evaluated the accuracy of the automicrobic system gram-negative identification card (vitek systems, inc., hazelwood, mo.) in identifying glucose-nonfermenting gram-negative bacilli by testing 419 selected isolates in parallel with a conventional reference method. of 356 isolates included in the automicrobic system profile, a total of 307 (86.2%) were correctly identified, 36 (10.1%) were not identified, and 13 (3.7%) were misidentified. fifty-eight of 63 (92% ... | 1986 | 3517050 |
| fate of selectable marker dna integrated into the genome of nicotiana tabacum. | to compare the effects of different transformation methods on the integration behavior and structural stability of integrated foreign genes in plant cells, tobacco protoplasts were transformed with escherichia coli plasmid plgv2103neo dna using the ca phosphate dna coprecipitation technique. parallel transformations were done by cocultivation with agrobacterium tumefaciens harboring the ti plasmid derivatives pgv3850::2103neo or pgv3850::1103neo. a comparison of the fine structure of the integra ... | 1986 | 3519133 |
| modification of t-dna of nopaline ti plasmid by intermediary vector and utilization of agrocin 84 sensitivity as simple criterion of conjugation transfer of modified ti plasmid. | the chloramphenicol resistance gene from psa was introduced into t-dna of pti t37 of agrobacterium tumefaciens by cointegration with intermediary plasmid based on pbr322. the resulting intermediary vector was mobilized to a. tumefaciens t37 by conjugative plasmid prk2. the rk2 plasmid also forms contegrates with pti due to the tn3 transposon which was used for the mobilization of modified pti into plasmid-less a. tumefaciens strain. transconjugants were selected on the basis of their antibiotic ... | 1986 | 3519390 |
| aerobic purification of hydrogenase from rhizobium japonicum by affinity chromatography. | we purified active hydrogenase from free-living rhizobium japonicum by affinity chromatography. the uptake hydrogenase of r. japonicum has been treated previously as an oxygen-sensitive protein. in this purification, however, reducing agents were not added nor was there any attempt to exclude oxygen. in fact, the addition of sodium dithionite to aerobically purified protein resulted in the rapid loss of activity. purified hydrogenase was more stable when stored under o2 than when stored under ar ... | 1986 | 3519580 |
| signal exchange in plant-microbe interactions. | | 1986 | 3523189 |
| the effect of the dissolved oxygen concentration and anabolic limitations on the behaviour of rhizobium ors571 in chemostat cultures. | chemostat cultures of rhizobium ors571 limited by the supply of oxygen or an anabolic substrate contained poly-beta-hydroxybutyrate (phb). low amounts of phb (about 10%) were present in ammonia- or nitrate-limited cultures; higher amounts were found in mg++-limited cultures (about 20%) and in oxygen-limited nitrogen-fixing cultures (37%). a method is described to calculate yatp values (g phb-free biomass . mol-1 atp) from the ysucc values (g dry wt . mol-1 succinate) measured. ysucc and yatp val ... | 1986 | 3524445 |
| reversible inactivation of the o2-labile hydrogenases from azotobacter vinelandii and rhizobium japonicum. | hydrogenases catalyze the reversible activation of dihydrogen. the hydrogenases from the aerobic, n2-fixing microorganisms azotobacter vinelandii and rhizobium japonicum are nickel- and iron-containing dimers that belong to the group of o2-labile enzymes. exposure of these hydrogenases to o2 results in an irreversible inactivation; therefore, these enzymes are purified anaerobically in a fully active state. we describe in this paper an electron acceptor-requiring and ph-dependent, reversible ina ... | 1986 | 3525552 |
| endogenous lectins from cultured soybean cells: isolation of a protein immunologically cross-reactive with seed soybean agglutinin and analysis of its role in binding of rhizobium japonicum. | incubation of rhizobium japonicum with the cultured soybean cell line sb-1, originally derived from the roots of glycine max, resulted in specific adhesion of the bacteria to the plant cells. this binding interaction appears to be mediated via carbohydrate recognition, since galactose can inhibit the heterotypic adhesion but glucose cannot. affinity chromatography, on a sepharose column derivatized with n-caproyl-galactosamine, of the supernatant fraction of a sb-1 cell suspension after enzymati ... | 1986 | 3528167 |
| initial interactions of agrobacterium tumefaciens with plant host cells. | infections of wounded dicotyledonous plants by agrobacterium tumefaciens result in the formation of crown gall tumors. the initial step in tumor formation is the site-specific attachment of the bacteria to the host cells. the mechanism of recognition and attachment in this interaction has been studied in detail. current information on the nature of the bacterial binding sites, the nature of the host receptors, the role of bacterial cellulose fibrils, and the genetics of bacterial attachment will ... | 1986 | 3533427 |
| a cell-free system from rhizobium meliloti to study the specific expression of nodulation genes. | an in vitro transcription-translation system was developed using cell-free extracts from the symbiotic nitrogen-fixing bacterium rhizobium meliloti strain 41. conditions for preparation of the 30,000 x g supernatant extract and for measurement of protein-synthesizing activity were determined and compared to the activity of an escherichia coli cell-free system. genes expressed in the free-living or in the symbiotic state were studied. the product of a reca-like gene (41-kda protein) was synthesiz ... | 1986 | 3533532 |
| a binary vector for transferring genomic libraries to plants. | the transformation of mutant plants with a complete recombinant library derived from wild-type dna followed by assay of transformed plants for complementation of the mutant phenotype is a promising method for the isolation of plant genes. the small genome of arabidopsis thaliana is a good candidate for attempting this so-called shotgun transformation. we present the properties of an a. thaliana genomic library cloned in a binary vector, pc22. this vector, designed to introduce genomic libraries ... | 1986 | 3534794 |
| microaerophily and oxygen toxicity. | | 1986 | 3535642 |
| competition for nodulation of legumes. | | 1986 | 3535643 |
| pairwise perturbation of flagellin subunits. the structural basis for the differences between plain and complex bacterial flagellar filaments. | although plain and complex bacterial flagellar filaments differ in their physical properties and helical symmetry, they both appear to derive from a common underlying structure. analysis of electron micrographs of complex filaments of rhizobium lupini revealed that the unit cell has twice the length of that of plain filaments, with a corresponding reduction in helical symmetry whereby the six-start helical family present in plain filaments collapses into a three-start family. mass per unit lengt ... | 1986 | 3537316 |
| induction of the noda promoter of rhizobium leguminosarum sym plasmid prl1ji by plant flavanones and flavones. | an expression vector containing the rhizobium leguminosarum noda promoter cloned in front of the escherichia coli lacz gene was used to characterize the properties of the r. leguminosarum noda gene-inducing compound(s) present in sterile root exudate of the host plant vicia sativa l. subsp. nigra (l.). the major inducing compound was flavonoid in nature, most likely a flavanone. the commercially available flavonoids naringenin (5,7,4'-trihydroxyflavanone), eriodictyol (5,7,3'4'-tetrahydroxyflava ... | 1987 | 3539915 |
| nucleotide sequence of the gene encoding the nitrogenase iron protein of thiobacillus ferrooxidans. | the dna sequence was determined for the cloned thiobacillus ferrooxidans nifh and part of the nifd genes. a putative t. ferrooxidans nifh promoter was identified whose sequences showed perfect consensus with those of the klebsiella pneumoniae nif promoter. two putative consensus upstream activator sequences were also identified. the amino acid sequence was deduced from the dna sequence. in a comparison of nifh dna sequences from t. ferrooxidans and eight other nitrogen-fixing microbes, a rhizobi ... | 1987 | 3539923 |
| isolation of tobacco dna segments with plant promoter activity. | we constructed a promoter probe vector, pgvl120, to isolate plant dna segments with promoter activity in tobacco. plant nuclear dna sau3a fragments were inserted in front of the npt-ii sequence, and a mixture of recombinant plasmids was mobilized to agrobacterium sp. and used to transform tobacco protoplasts. by kanamycin selection, transformed plant cell lines containing npt-ii t-dnas were isolated. eight of these cell lines were regenerated and analyzed for the levels of npt-ii activity in ste ... | 1986 | 3540612 |
| [conjugation transfer of the bireplicon plasmid pspa044 into rhizobiaceae bacteria]. | we have demonstrated the possibility of hybrid plasmid pspa044 conjugative transfer from e. coli cells into different rhizobium species. the bireplicon plasmid, constructed earlier in our laboratory, consisting of pbr325 and hindiii fragment 13 of the nopaline plasmid ptic58 was mobilized for transfer by the helper plasmid prk2013 with the frequency about 10(-4). we conclude the hybrid plasmid pspa044 to be able to replicate stably in rhizobiaceae cells. | 1986 | 3540635 |
| transformation of the genomic expression of plant cells. | agrobacterium-induced transformation of plant cells results from integration of t-dna of the ti or ri plasmids into the genome of susceptible plants. expression of t-dna genes induces physiological changes in transformed cells which modify normal plant development to produce proliferations characteristic of crown gall and hairy root diseases. understanding of the molecular basis of the transformation events associated with these examples of naturally occurring genetic engineering of plant cells, ... | 1986 | 3544312 |
| regulation of nitrogen fixation genes. | | 1986 | 3545064 |