Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
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| direct evidence of the entner-doudoroff pathway operating in the metabolism of d-glucosamine in bacteria. | pseudomonas fluorescens (migula) (ifo 14808) has both a membrane-bound pqq-dependent d-glucose (d-glc) dehydrogenase [ec 1.1.99.17] [which also acts on d-glucosamine (d-glcn)] and a plp-dependent d-glucosaminate (d-glcna) dehydratase [ec 4.2.1.26]. further, these two enzymes were induced when d-glcn was added to the culture medium. however, d-glucosamine-6-phosphate (d-glcn-6-p) isomerase [ec 5.3.1.10], another enzyme involved in the metabolism of d-glcn, was only present at a low level in this ... | 1991 | 1849886 |
| characterization of three agrobacterium tumefaciens avirulent mutants with chromosomal mutations that affect induction of vir genes. | three agrobacterium tumefaciens mutants with chromosomal mutations that affect bacterial virulence were isolated by transposon mutagenesis. two of the mutants were avirulent on all hosts tested. the third mutant, ivr-211, was a host range mutant which was avirulent on bryophyllum diagremontiana, nicotiana tabacum, n. debneyi, n. glauca, and daucus carota but was virulent on zinnia elegans and lycopersicon esculentum (tomato). that the mutant phenotype was due to the transposon insertion was dete ... | 1991 | 1846853 |
| phytochrome control of the tms2 gene in transgenic arabidopsis: a strategy for selecting mutants in the signal transduction pathway. | introduction of the tms2 gene from agrobacterium tumefaciens into arabidopsis thaliana yields transgenic seedlings with a new selectable phenotype: the seedlings are strongly growth inhibited on micromolar concentrations of auxin amide substrates that do not significantly affect wild-type seedlings. the tms2 gene encodes an amidohydrolase that catalyzes the conversion of biologically inactive auxin amides into active auxins, which are toxic to plants at elevated concentrations. in the absence of ... | 1991 | 1841718 |
| tomato yellow leaf curl virus from sardinia is a whitefly-transmitted monopartite geminivirus. | the genome of an isolate of tomato yellow leaf curl virus from sardinia, italy (tylcv-s), a geminivirus transmitted by the whitefly bemisia tabaci, has been cloned and sequenced. the single circular dna molecule comprises 2770 nucleotides. genome organisation closely resembles that of the dna a component of the whitefly-transmitted geminiviruses with a bipartite genome. a 1.8 mer of the tylcv-s genome in a binary vector of agrobacterium tumefaciens is infectious upon agroinoculation of tomato pl ... | 1991 | 1840676 |
| the osa gene of psa encodes a 21.1-kilodalton protein that suppresses agrobacterium tumefaciens oncogenicity. | the incompatibility group w plasmid psa suppresses agrobacterium tumefaciens oncogenicity (j. loper and c. kado, j. bacteriol. 139:591-596, 1979). the oncogenic suppressive activity was localized to a 3.1-kb region of psa by tn5 mutagenesis and deletion analysis. within this fragment, a 1.1-kb subclone bearing oncogenic suppressive activity was subjected to further characterization. nucleotide sequencing of the 1.1-kb fragment revealed a 570-bp open reading frame (orf1) that has a coding capacit ... | 1991 | 1832152 |
| characterization of an agrobacterium tumefaciens lectin. | an agrobacterium tumefaciens suspension induces a strong agglutination of aldehyde-fixed pig erythrocytes at ph 5.0. the agglutination is inhibited by some polysaccharides, such as fucoidin, and also when the ph is raised to 7.0. lectins (sugar-binding proteins) associated with the bacterial cell wall of a. tumefaciens strain 84.5 were directly evidenced by spectrofluorimetry using fluoresceinylated neoglycoproteins. the specific binding of the fluorescein-labelled neoglycoprotein bearing alpha- ... | 1991 | 1822244 |
| synergistic action of phenolic signal compounds and carbohydrates in the induction of virulence gene expression of agrobacterium tumefaciens. | virulence (vir) gene expression of agrobacterium tumefaciens is activated by plant phenolic compounds such as alpha-hydroxyacetosyringone (hoas), acetosyringone (as), methyl syringate, coniferyl alcohol and sinapyl alcohol. inositol was found to be a potentiating factor of vir-inducing activity, which enhanced the vir-inducing activity of as and hoas in a synergistic manner, in particular at a low concentrations of as and hoas. of the other sugars tested d-glucose, l-rhamnose, d-xylose and d-gal ... | 1991 | 1806280 |
| identification of 3-deoxy-lyxo-2-heptulosaric acid in the core region of lipopolysaccharides from rhizobiaceae. | a 3-deoxy-2-heptulosaric acid (dha), very probably with the lyxo-configuration, was identified in the r-core region of lipopolysaccharides from nodulating strains of rhizobium leguminosarum, rhizobium meliloti and from all three biovars of the phytopathogenic agrobacterium tumefaciens. its structure could be deduced from the fragmentation pattern of the corresponding alditol acetates obtained after reduction of the 2-keto and the 1.7-carboxy groups by sodium borohydride or sodium borodeuteride. ... | 1991 | 1804765 |
| expression of rhizobium galegae common nod clones in various backgrounds. | the cosmid clone prg30, carrying common nodulation genes of rhizobium galegae hambi 1174, and prg33, a subclone of prg30 that contains a 5.7-kb clai insert carrying noddabc were conjugated into various rhizobium nod- mutant strains and into a ti plasmid-cured agrobacterium tumefaciens. complementation and expression of the nodabc genes of r. galegae were studied by following microscopically the infection process and the nodulation on different test plants. the nodabc genes of r. galegae compleme ... | 1991 | 1804401 |
| mutants of the agrobacterium tumefaciens vira gene exhibiting acetosyringone-independent expression of the vir regulon. | hydroxylamine-induced mutations in the vira gene of agrobacterium tumefaciens that do not require the plant phenolic-inducing compound acetosyringone for vir regulon induction were isolated. the isolation was based on the activation of both virb::lacz and vire::cat fusions by mutant vira loci in the absence of acetosyringone. three of these vira(ais) (acetosyringone-independent signaling) mutants were characterized. all three mutants expressed a virb::lacz fusion at high levels in the absence of ... | 1991 | 1799700 |
| transcription of the octopine catabolism operon of the agrobacterium tumor-inducing plasmid ptia6 is activated by a lysr-type regulatory protein. | agrobacterium tumefaciens incites crown gall tumors on plant hosts by conjugally transferring a discrete fragment of oncogenic dna. in addition to oncogenes, the transferred dna contains genes that direct the synthesis and exudation of opines, which are used as nutrients by the bacteria. the bacterium contains one or more operons of ti plasmid-encoded genes that are required for the internalization and utilization of opines, and transcription of these catabolic genes is induced by cognate opines ... | 1991 | 1799699 |
| positive regulators of opine-inducible promoters in the nopaline and octopine catabolism regions of ti plasmids. | the noc and occ regions of nopaline and octopine ti plasmids in agrobacterium tumefaciens contain genes for the catabolism of nopaline and octopine, respectively. we investigated the transcriptional organization and regulation of both regions. the noc region of ptic58 contains two nopaline-inducible promoters, and one octopine-inducible promoter was identified in the occ region of ptiach5. all three promoters are positively regulated in trans by constitutively expressed genes localized at the ri ... | 1991 | 1799698 |
| an agrobacterium two-component regulatory system for the detection of chemicals released from plant wounds. | crown gall tumorigenesis by agrobacterium tumefaciens requires the co-ordinate transcriptional induction of a set of pathogenesis genes. at least three classes of environmental stimuli act synergistically to induce these genes: (i) monocyclic aromatic hydrocarbons such as acetosyringone, coniferyl alcohol, and vanillin, (ii) neutral or acidic monosaccharides such as glucose and glucuronic acid, and (iii) acidic ph. three proteins are required to sense and respond to these stimuli: (i) vira, a tr ... | 1991 | 1791750 |
| swimming against the tide: chemotaxis in agrobacterium. | chemotaxis in bacteria is an excellent model for signal transduction processes. in agrobacterium tumefaciens, the causative agent of crown gall tumour on wounded plants, it is a vital part of the organism's biology. a chromosomally-determined chemotaxis system causes the bacterium to be attracted into the rhizosphere by chemoattractants in plant exudates. by interfacing with this system, the multifunctional products of two ti-plasmid encoded genes, vira and virg, allow the sensing of specific wo ... | 1991 | 1772407 |
| characterization of the supervirulent virg gene of the agrobacterium tumefaciens plasmid ptibo542. | the virg gene of the agrobacterium tumefaciens ti plasmid ptibo542 has previously been reported to elicit stronger vir gene expression than its counterpart in the ptia6 plasmid, a property we call the "superactivator" phenotype. the dna sequence of the ptibo542 virg gene was determined and compared to that of the ptia6 gene. the dna sequences of these genes differ at 16 positions: two differences are in the promoter regions, 12 are in the coding regions, and two are in the 3' untranslated region ... | 1991 | 1745238 |
| the agrobacterium tumefaciens vir gene transcriptional activator virg is transcriptionally induced by acid ph and other stress stimuli. | a set of agrobacterium tumefaciens operons required for pathogenesis is coordinately induced during plant infection by the vira and virg proteins. the intracellular concentration of virg increases in response to acidic media, and this response was proposed to be regulated at the level of transcription at a promoter (p2) that resembles the escherichia coli heat shock promoters. to test this hypothesis, we first constructed a virg-lacz transcriptional fusion. a strain containing this fusion had hi ... | 1992 | 1735712 |
| a self-transmissible, narrow-host-range endogenous plasmid of rhodobacter sphaeroides 2.4.1: physical structure, incompatibility determinants, origin of replication, and transfer functions. | rhodobacter sphaeroides 2.4.1 naturally harbors five cryptic endogenous plasmids (c. s. fornari, m. watkins, and s. kaplan, plasmid 11:39-47, 1984). the smallest plasmid (prs241e), with a molecular size of 42 kb, was observed to be a self-transmissible plasmid which can transfer only to certain strains of r. sphaeroides. transfer frequencies can be as high as 10(-2) to 10(-3) per donor under optimal mating conditions in liquid media in the absence of oxygen. prs241e, designated the s factor, was ... | 1992 | 1735707 |
| mutation of the miaa gene of agrobacterium tumefaciens results in reduced vir gene expression. | vir regulon expression in agrobacterium tumefaciens involves both chromosome- and ti-plasmid-encoded gene products. we have isolated and characterized a new chromosomal gene that when mutated results in a 2- to 10-fold reduction in the induced expression of vir genes by acetosyringone. this reduced expression occurs in ab minimal medium (ph 5.5) containing either sucrose or glucose and containing phosphate at high or low concentrations. the locus was cloned and used to complement a. tumefaciens ... | 1992 | 1735704 |
| characterization of the agrobacterium tumefaciens heat shock response: evidence for a sigma 32-like sigma factor. | we have characterized the heat shock response of agrobacterium tumefaciens and compared it with the well-characterized escherichia coli heat shock response. four major heat shock proteins with apparent molecular masses of 98, 75, 65, and 20 kda were identified by pulse-labelling cultures after temperature upshift. the three largest proteins comigrated with proteins that were antigenically related to the e. coli heat shock proteins sigma 70, dnak, and groel, respectively. the heat shock proteins ... | 1992 | 1732231 |
| opine transport genes in the octopine (occ) and nopaline (noc) catabolic regions in ti plasmids of agrobacterium tumefaciens. | the occ and noc regions of octopine and nopaline ti plasmids in agrobacterium tumefaciens are responsible for the catabolic utilization of octopine and nopaline, respectively. opine-inducible promoters, genes for regulatory proteins and for catabolic enzymes, had been identified in previous work. however, both regions contained additional dna stretches which were under the control of opine-inducible promoters, but the functions were unknown. we investigated these stretches by dna sequence and fu ... | 1992 | 1732218 |
| opine catabolism and conjugal transfer of the nopaline ti plasmid ptic58 are coordinately regulated by a single repressor. | the ti plasmids of agrobacterium tumefaciens are conjugal elements whose transfer is strongly repressed. transfer is induced by the conjugal opines, a group of unique carbon compounds synthesized in crown gall tumors. the opines also induce ti plasmid-encoded genes required by the bacteria for opine catabolism. we have cloned and sequenced a gene from the ti plasmid ptic58, whose product mediates the opine-dependent regulation of conjugal transfer and catabolism of the conjugal opines, agrocinop ... | 1992 | 1731335 |
| expression of cowpea mosaic virus coat protein precursor in transgenic tobacco plants. | tobacco, nicotiana tabacum l., supports cowpea mosaic virus (cpmv) replication and cell-to-cell movement, and thus may serve as a model system to study coat protein-mediated protection against cpmv. a chimeric gene consisting of the cauliflower mosaic virus 35s promoter, cpmv 60k coat proteins-precursor (cp-p) coding region, and the nopaline synthase polyadenylation signal was transferred to tobacco cv. burley 21 via the agrobacterium tumefaciens binary vector system. gene integration and expres ... | 1992 | 1730936 |
| integration and expression of a rabbit liver cytochrome p-450 gene in transgenic nicotiana tabacum. | cytochrome p-450 is involved in the oxidative metabolism of a broad range of substrates. we have made a chimeric construct, psn002, containing the cdna for rabbit liver cytochrome p-450 (iic14) under the control of the tr2' promoter for mannopine synthase in the agrobacterium ti plasmid. nicotiana tabacum was transformed with agrobacterium tumefaciens harboring a cointegrated plasmid psn002::pgv2260. the presence of mrna and of the translated protein from the chimeric cytochrome p-450 gene in tr ... | 1991 | 1714583 |
| cross-talk between the virulence and phosphate regulons of agrobacterium tumefaciens caused by an unusual interaction of the transcriptional activator with a regulatory dna element. | transcription of a virulence gene on the hairy-root-inducing plasmid a4, which is induced by plant factors in agrobacterium tumefaciens, was also activated by phosphate limitation in both a. tumefaciens and escherichia coli. the starting site of rna synthesized under the two inducing conditions was the same, and an identical promoter was responsible for both inducible expressions. the response of the virulence gene to phosphate limitation did not require the positive regulator virg for the virul ... | 1991 | 1714035 |
| transgenic rice cell lines and plants: expression of transferred chimeric genes. | cell suspension-derived rice (oryza sativa l.) protoplasts were transformed by direct gene uptake. peg-mediated transformation was more efficient than electroporation. plasmid dna containing a hygromycin phosphotransferase (hpt) gene (which confers hygromycin resistance) driven by the camv 35s promoter and a beta-d-glucuronidase (gus) gene under control of the 1', 2' double promoter of the mannopine synthase (mas) locus of agrobacterium tumefaciens was introduced into rice protoplasts. southern ... | 1991 | 1713479 |
| complementation of an rnase p rna (rnpb) gene deletion in escherichia coli by homologous genes from distantly related eubacteria. | we report the construction of a strain of escherichia coli in which the only functional gene for the rna moiety of rnase p (rnpb) resides on a plasmid that is temperature sensitive for replication. the chromosomal rnase p rna gene was replaced with a chloramphenicol acetyltransferase gene. the conditionally lethal phenotype of this strain was suppressed by plasmids that carry rnase p rna genes from some distantly related eubacteria, including alcaligenes eutrophus, bacillus subtilis, and chromat ... | 1990 | 1699929 |
| characterisation of a pseudomonas aeruginosa twitching motility gene and evidence for a specialised protein export system widespread in eubacteria. | type-4 fimbriae (pili) are associated with a phenomenon known as twitching motility, which appears to be involved with bacterial translocation across solid surfaces. pseudomonas aeruginosa mutants which produce fimbriae, but which have lost the twitching motility function, display altered colony morphology and resistance to fimbrial-specific bacteriophage. we have used phenotypic complementation of such mutants to isolate a region of dna involved in twitching motility. this region was physically ... | 1991 | 1676385 |
| studies of the bradyrhizobium japonicum nodd1 promoter: a repeated structure for the nod box. | induction of nod genes in rhizobium and bradyrhizobium species is dependent on the presence of plant-produced flavonoids, the nodd protein, and the cis-acting nod box promoter sequence. although the nodd (nodd1) gene in rhizobium species is constitutively expressed, nodd1 expression in bradyrhizobium japonicum is inducible by isoflavones in a manner similar to that of the nodyabc operon. a consensus nod box sequence is found 5' of the nodyabc operon, whereas a presumptive, nod box-like sequence ... | 1991 | 1675210 |
| polymorphism of nopaline-type t-dnas from agrobacterium tumefaciens. | the structure of several t-dnas of agrobacterium tumefaciens was determined by molecular cloning and southern hybridization. the t-dnas cloned in escherichia coli vectors from four different nopaline type strains (pyte1, po31, po22, and ake10) showed various sizes of restriction enzyme fragments. comparative analysis of the restriction maps revealed that the t-dnas were composed of three distinct structural domains: (1) the region proximal to the right border (domain i) containing the portion es ... | 1991 | 1674610 |
| regeneration of transgenic lycium barbarum l. | a simple and effective system for the transformation and regeneration of lycium barbarum l. has been developed. young stem segments from lycium barbarum l. were infected by agrobacterium tumefaciens harboring a vector containing neomycin phosphotransferase ii (npt-ii) gene derived from non-oncogenic ti plasmid. calli originating from young stem segments on selective induction medium could differentiate into buds on selective differentiation medium rapidly and finally developed into whole plants. ... | 1991 | 1668526 |
| nucleotide sequence of rhizobium meliloti insertion sequence isrm1: homology to is2 from escherichia coli and is426 from agrobacterium tumefaciens. | nucleotide sequencing of rhizobium meliloti insertion sequence isrm1 showed that it is 1319 nucleotides long and includes 32/31 nucleotide terminal inverted repeats. analysis of five different insertion sites using sequencing primers complementary to sequences within the left and right ends demonstrated that isrm1 generates five bp direct repeats at the sites of insertion. although isrm1 has shown a target preference for certain short regions (hot spots), there was no apparent similarity in the ... | 1991 | 1667984 |
| nucleotide sequence and organization of genes flanking the transfer origin of promiscuous plasmid rp4. | the nucleotide sequence of the relaxase operon and the leader operon which are part of the tra1 region of the promiscuous plasmid rp4 was determined. these two polycistronic operons are transcribed divergently from an intergenic region of about 360 bp containing the transfer origin and six close-packed genes. a seventh gene completely overlaps another one in a different reading frame. conjugative dna transfer proceeds unidirectionally from orit with the leader operon heading the dna to be transf ... | 1991 | 1665997 |
| mapping of the ros virulence regulatory gene of a. tumefaciens. | virulence functions associated with the oncogenicity of agrobacterium tumefaciens are encoded by vir genes contained in six major operons located on the ti plasmid. the virc and vird operons encode functions responsible for host range and t-intermediate processing. these two operons are regulated positively by the product of virg and negatively by the product of the chromosomal gene ros, which encodes a 15.5 kda repressor. to determine the location of the ros gene we have constructed a. tumefaci ... | 1991 | 1660566 |
| characterization of cytochromes c550 and c555 from bradyrhizobium japonicum: cloning, mutagenesis, and sequencing of the c555 gene (cycc). | the major soluble c-type cytochromes in cultured cells of bradyrhizobium japonicum usda 110 comprised a co-reactive c555 (mr, approximately 15,500) and a non-co-reactive c550 (mr, approximately 12,500). levels of cytochrome per gram of soluble protein in aerobic, anaerobic, and symbiotic cells were 32, 21, and 30 nmol, respectively, for c555 and 31, 44, and 65 nmol, respectively, for c550. the midpoint redox potentials (em,7) of the purified cytochromes were +236 mv for c555 and +277 mv for c550 ... | 1991 | 1660457 |
| limited host range ti plasmids: recent origin from wide host range ti plasmids and involvement of a novel is element, is868. | agrobacterium tumefaciens biotype iii octopine strains have been isolated from grapevine tumors worldwide. they comprise limited and wide host range (lhr and whr) strains that carry related tumor-inducing (ti) plasmids with two t-regions, ta and tb. the whr ta-region resembles the biotype i octopine region, whereas the lhr ta-region is a recent deletion derivative of the whr ta-region, which lacks the iaa genes and part of the ipt gene. sequencing of the ta-region of the ubiquitous lhr strain ab ... | 1991 | 1657255 |
| polygalacturonase is a virulence factor in agrobacterium tumefaciens biovar 3. | agrobacterium tumefaciens biovar 3 causes both crown gall and root decay of grapes. all biovar 3 strains, regardless of their tumorigenicity, produce in culture a single polygalacturonase with a pi around 4.5. a. tumefaciens biovar 3 strain cg49 was mutagenized with tn5 by using psup2021 as a suicide vector. a mutant strain, cg50, lacking polygalacturonase activity was isolated. the mutation was due to a single tn5 insertion in an 8.5-kb ecori fragment that also contained the polygalacturonase s ... | 1991 | 1655716 |
| characterization of a putative periplasmic transport system for octopine accumulation encoded by agrobacterium tumefaciens ti plasmid ptia6. | neoplastic crown gall tumors incited by agrobacterium tumefaciens release novel amino acid or sugar derivatives known as opines, whose synthesis is directed by genes transferred to plant cells. agrobacterium cells can transport and catabolize these compounds as sources of carbon and nitrogen. this article describes a region of the ptia6 plasmid which is required for catabolism of the opine octopine and whose transcription is induced by octopine. this region of the plasmid contains four open read ... | 1991 | 1655707 |
| polypeptide composition of bacterial cyclic diguanylic acid-dependent cellulose synthase and the occurrence of immunologically crossreacting proteins in higher plants. | to comprehend the catalytic and regulatory mechanism of the cyclic diguanylic acid (c-di-gmp)-dependent cellulose synthase of acetobacter xylinum and its relatedness to similar enzymes in other organisms, the structure of this enzyme was analyzed at the polypeptide level. the enzyme, purified 350-fold by enzyme-product entrapment, contains three major peptides (90, 67, and 54 kda), which, based on direct photoaffinity and immunochemical labeling and amino acid sequence analysis, are constituents ... | 1991 | 1647035 |
| nolc, a rhizobium fredii gene involved in cultivar-specific nodulation of soybean, shares homology with a heat-shock gene. | rhizobium fredii strain usda257 does not nodulate soybean (glycine max (l.) merr.) cultivar mccall. mutant 257dh5, which contains a tn5 insert in the bacterial chromosome, forms nodules on this cultivar, but acetylene-reduction activity is absent. we have sequenced the region corresponding to the site of tn5 insertion in this mutant and find that it lies within a 1176bp open reading frame that we designate nolc. nolc encodes a protein of deduced molecular weight 43564. nucleotide sequences homol ... | 1991 | 1646377 |
| vectors for plant transformation and cosmid libraries. | a series of vectors has been constructed for the purpose of introducing cloned dnas into plant genomes, using agrobacterium tumefaciens-mediated transformation methods. one of these vectors, pcit20, is a plasmid that contains a multiple cloning site (mcs), and a marker (hph) that confers hygromycin resistance to plant cells. the others are all cosmid vectors which allow insertion of up to 46 kb of plant genomic dna, and which also contain all of the necessary sequences for a. tumefaciens-mediate ... | 1992 | 1639265 |
| molecular analysis of the lac operon encoding the binding-protein-dependent lactose transport system and beta-galactosidase in agrobacterium radiobacter. | the genes coding for the binding-protein-dependent lactose transport system and beta-galactosidase in agrobacterium radiobacter strain ar50 were cloned and partially sequenced. a novel lac operon was identified which contains genes coding for a lactose-binding protein (lace), two integral membrane proteins (lacf and lacg), an atp-binding protein (lack) and beta-galactosidase (lacz). the operon is transcribed in the order lacefgzk. the operon is controlled by an upstream regulatory region contain ... | 1992 | 1630315 |
| the agrobacterium tumefaciens vird3 gene is not essential for tumorigenicity on plants. | genetic studies indicate that three of the four polypeptides encoded within the vird operon of the agrobacterium tumefaciens ti plasmid are essential for virulence. in order to determine whether the fourth polypeptide, vird3, has any role in virulence, complementation analysis was used. an a. tumefaciens strain, a348 delta d, which lacked the entire vird operon in the ti plasmid ptia6, was constructed. plasmids containing defined regions of the vird operon were introduced into this strain, and v ... | 1992 | 1629176 |
| transgenic medicinal plants: agrobacterium-mediated foreign gene transfer and production of secondary metabolites. | agrobacterium-ti/ri plasmids are natural gene vectors, by which a number of attempts have been made in genetic engineering of secondary metabolism in pharmaceutically important plants in the last few years. opines are biosynthesized by transformed crown galls and hairy roots integrated with t-dnas of ti/ri plasmids. these opines are classified into five families according to their structures and biogenesis. the production of opines is a natural example of genetic engineering of the biosynthetic ... | 1992 | 1624938 |
| heavy metals alter the electrokinetic properties of bacteria, yeasts, and clay minerals. | the electrokinetic patterns of four bacterial species (bacillus subtilis, bacillus megaterium, pseudomonas aeruginosa, and agrobacterium radiobacter), two yeasts (saccharomyces cerevisiae and candida albicans), and two clay minerals (montmorillonite and kaolinite) in the presence of the chloride salts of the heavy metals, cd, cr, cu, hg, ni, pb, and zn, and of na and mg were determined by microelectrophoresis. the cells and kaolinite were net negatively charged at ph values above their isoelectr ... | 1992 | 1622229 |
| a staphylococcal multidrug resistance gene product is a member of a new protein family. | the complete nucleotide sequence (321 bp) of smr (staphylococcal multidrug resistance), a gene coding for efflux-mediated multidrug resistance of staphylococcus aureus, was determined by using two different plasmids as dna templates. the smr gene product (identical to products of ebr and qacc/d genes) was shown to be homologous to a new family of small membrane proteins found in escherichia coli, pseudomonas aeruginosa, agrobacterium tumefaciens, and proteus vulgaris. the smr gene was subcloned ... | 1992 | 1615062 |
| resistance to tomato spotted wilt virus infection in transgenic tobacco expressing the viral nucleocapsid gene. | a recombinant plasmid containing the entire tomato spotted with virus (tswv) nucleocapsid gene, with the exception of nucleotide encoding three n-terminal amino acids, was isolated by screening a complementary dna library, prepared against random primed viral rna, using a specific monoclonal antibody. the insert contained in plasmid ptsw1 was repaired and amplified by polymerase chain reaction, and the complete nucleocapsid protein gene was introduced into nicotiana tabacum 'samsun' by leaf disk ... | 1992 | 1600236 |
| constitutive mutations of agrobacterium tumefaciens transcriptional activator virg. | the virulence (vir) genes of agrobacterium tumefaciens ti plasmids are positively regulated by virg in conjunction with vira and plant-derived inducing molecules. a procedure that utilizes both genetic selection and a genetic screen was developed to isolate mutations in virg that led to elevated levels of vir gene expression in the absence of vira and plant phenolic inducers. mutants were isolated at a frequency of 1 in 10(7) to 10(8). substitution mutations at two positions in the virg coding r ... | 1992 | 1597431 |
| analysis of mutations in trfa, the replication initiation gene of the broad-host-range plasmid rk2. | plasmids with mutations in trfa, the gene encoding the replication initiation protein of the broad-host-range plasmid rk2, were isolated and characterized. mutants identified from a nitrosoguanidine bank were defective in supporting the replication of a wild-type rk2 origin in escherichia coli. most of the mutations were clustered in a region of trfa corresponding to the carboxy-terminal quarter of the trfa protein. 5' and 3' deletion mutants of trfa were also constructed. a c-terminal deletion ... | 1992 | 1597426 |
| the a. tumefaciens transcriptional activator occr causes a bend at a target promoter, which is partially relaxed by a plant tumor metabolite. | octopine is released from crown gall tumors as a nutrient source and a signal molecule for the plant pathogen agrobacterium tumefaciens. some or all octopine-inducible genes are regulated by a protein called occr. primer extension analysis showed that occr protein represses the occr gene and both represses and activates the occq operon, which is divergently transcribed from occr. these promoters initiate transcription 46 bp apart. this regulatory system was reconstituted in vitro using purified ... | 1992 | 1586946 |
| expression of a chimaeric heat-shock-inducible agrobacterium 6b oncogene in nicotiana rustica. | the t-6b gene of agrobacterium tumefaciens strain tm4 induces tumours on nicotiana rustica by an as yet unknown mechanism. these tumours cannot be regenerated into normal plants. to study the effect of the t-6b gene product on normal plant cells, the t-6b gene was placed under control of the drosophila melanogaster hsp70 heat-shock promoter and introduced into n. rustica. progeny of an hsp70-t-6b transformant developed into normal plants. the inducibility of the hsp70-t-6b construct was shown by ... | 1992 | 1581569 |
| self-splicing introns in trna genes of widely divergent bacteria. | the organization of eukaryotic genes into exons separated by introns has been considered as a primordial arrangement but because it does not exist in eubacterial genomes it may be that introns are relatively recent acquisitions. a self-splicing group i intron has been found in cyanobacteria at the same position of the same gene (that encoding leucyl transfer rna, uaa anticodon) as a similar group i intron of chloroplasts, which indicates that this intron predates the invasion of eukaryotic cells ... | 1992 | 1579169 |
| catheter-associated sepsis caused by ochrobactrum anthropi: report of a case and review of related nonfermentative bacteria. | ochrobactrum anthropi, formerly known as cdc group vd, is an oxidase-producing, gram-negative, non-lactose-fermenting bacillus that oxidizes glucose and grows readily on macconkey agar. only occasionally isolated from human clinical specimens, this organism has rarely been found to be pathogenic. we describe the first reported case of infection due to o. anthropi in a child, that of bacteremia in a 3-year-old girl undergoing chemotherapy for retinoblastoma. in addition, we review the literature ... | 1992 | 1576286 |
| spatial and temporal expression patterns directed by the agrobacterium tumefaciens t-dna gene 5 promoter during somatic embryogenesis in carrot. | we have analysed the patterns of expression of a gene encoding beta-glucuronidase (gus) fused to the promoter of the agrobacterium tumefaciens t-dna gene 5 during embryogenesis in carrot, daucus carota l. gene expression was monitored by a histochemical assay of beta-glucuronidase activity. the gene 5 promoter, although of bacterial origin, conferred expression upon the marker gene in all stages of embryo development. the patterns of expression however, differed between embryos in different stag ... | 1992 | 1558941 |
| biolistic transformation of prokaryotes: factors that affect biolistic transformation of very small cells. | five bacterial species were transformed using particle gun-technology. no pretreatment of cells was necessary. physical conditions (helium pressure, target cell distance and gap distance) and biological conditions (cell growth phase, osmoticum concentration, and cell density) were optimized for biolistic transformation of escherichia coli and these conditions were then used to successfully transform agrobacterium tumefaciens, erwinia amylovora, erwinia stewartii and pseudomonas syringae pv. syri ... | 1992 | 1556553 |
| the ntra gene of agrobacterium tumefaciens: identification, cloning, and phenotype of a site-directed mutant. | a 3.6-kb ecori fragment containing the ntra gene of agrobacterium tumefaciens was cloned by using the homologous ntra gene of rhizobium meliloti as a probe. construction of an ntra mutant of a. tumefaciens by site-directed insertional mutagenesis demonstrated the requirement of the ntra gene for nitrate utilization and c4-dicarboxylate transport but not for vir gene expression or tumorigenesis. | 1992 | 1556090 |
| spontaneous mutation conferring the ability to catabolize mannopine in agrobacterium tumefaciens. | two nopaline-type strains of agrobacterium tumefaciens, c58 and t37, as well as strain a136, which is a ti plasmid-cured derivative of strain c58, gave rise to spontaneous mutants that were able to grow on mannopine. the observation of mutagenesis with strain a136 demonstrated that the ability to acquire this new catabolic potential was independent of the presence of a ti plasmid. the mutants were isolated after 4 weeks of incubation on minimal medium containing mannopine as the sole carbon sour ... | 1992 | 1556082 |
| new functional assignment of the carotenogenic genes crtb and crte with constructs of these genes from erwinia species. | the role of carotenoid genes crtb and crte has been functionally assigned. these genes were cloned from erwinia into escherichia coli or agrobacterium tumefaciens. their functions were elucidated by assaying early isoprenoid enzymes involved in phytoene formation. in vitro reactions from extracts of e. coli carrying the crte gene or a complete carotenogenic gene cluster in which crtb was deleted showed an elevated conversion of farnesyl pyrophosphate (fpp) into geranylgeranyl pyrophosphate (ggpp ... | 1992 | 1555761 |
| agrobacterium tumefaciens transfers extremely long t-dnas by a unidirectional mechanism. | during crown gall tumorigenesis, part of the agrobacterium tumefaciens tumor-inducing (ti) plasmid, the t-dna, integrates into plant dna. direct repeats define the left and right ends of the t-dna, but tumorigenesis requires only the right-hand repeat. virulence (vir) genes act in trans to mobilize the t-dna into plant cells. transfer of t-dna begins when the vird endonuclease cleaves within the right-hand border repeat. although the t-dna right-border repeat promotes t-dna transmission best in ... | 1992 | 1551847 |
| diauxic growth of agrobacterium tumefaciens 15955 on succinate and mannopine. | diauxic growth was observed upon incubation of agrobacterium tumefaciens 15955 on a mixture of succinate and mannopine as the carbon source. diauxic growth was also observed when either fumarate or l-malate was mixed with mannopine. no diauxie was detectable when a. tumefaciens 15955 was grown on a mixture of mannopine and glucose, fructose, sucrose, or l-arabinose. preferential utilization of succinate was observed in the initial growth phase of diauxie, whereas the final growth phase occurred ... | 1992 | 1551843 |
| agroinfection of transgenic plants leads to viable cauliflower mosaic virus by intermolecular recombination. | intermolecular reconstitution of a plant virus has been detected in whole plants in a system using a defective cauliflower mosaic virus genome and transgenic host plants containing the missing viral gene. the information for the gene vi protein of the virus was integrated into the chromosome of host brassica napus plants and leaves of these plants were inoculated with agrobacterium tumefaciens containing the complementing viral sequences. in several cases, upper leaves contained replicating vira ... | 1992 | 1546451 |
| construction of bordetella pertussis strains that overproduce genetically inactivated pertussis toxin. | nontoxic analogs of pertussis toxin (pt), produced by in vitro mutagenesis of the tox operon, are immunogenic and protective against infection by bordetella pertussis. the moderate levels of pt production by b. pertussis, however, make it the limiting antigen in the formulation of multicomponent, acellular, recombinant whooping cough vaccines. to increase production of the highly detoxified lys9gly129 pt analog by b. pertussis, additional copies of the mutated tox operon were integrated into the ... | 1992 | 1539974 |
| cloning and sequencing of an agrobacterium tumefaciens beta-glucosidase gene involved in modifying a vir-inducing plant signal molecule. | induction of agrobacterium tumefaciens virulence genes by plant phenolic compounds is essential for successful t-dna transfer to a host plant. in douglas fir needles, the major virulence region inducer is the glycoside coniferin (j. w. morris and r. o. morris, proc. natl. acad. sci. usa 87:3612-3618, 1990). agrobacterium strains with high beta-glucosidase activity respond to coniferin and infect douglas fir seedlings, whereas most strains with low beta-glucosidase activity fail to respond to con ... | 1992 | 1537792 |
| a defective replicase gene induces resistance to cucumber mosaic virus in transgenic tobacco plants. | nicotiana tabacum cv. turkish samsun nn plants were transformed with a modified and truncated replicase gene encoded by rna-2 of cucumber mosaic virus strain fny. the replicase gene had been modified by deleting a 94-base-pair region spanning nucleotides 1857-1950; the deletion also caused a shift in the open reading frame, resulting in a truncated translation product approximately 75% as large as the full-length protein. upon transformation via agrobacterium tumefaciens, transgenic plants were ... | 1992 | 1528890 |
| mechanism of activation of agrobacterium virulence genes: identification of phenol-binding proteins. | agrobacterium tumefaciens initiates the expression of pathogenic genes (vir genes) in response to host-derived phenolic signals through a two-component regulatory system consisting of vira and virg. alpha-bromoacetosyringone (asbr) was developed as an inhibitor of this induction process and found to be a specific and irreversible inhibitor of vir gene induction in this pathogen. formal replacement of one of the methoxy groups of asbr with iodine gave an equally effective inhibitor that could car ... | 1992 | 1528878 |
| subdomains of the octopine synthase upstream activating element direct cell-specific expression in transgenic tobacco plants. | previous work has shown that the octopine synthase (ocs) gene encoded by the agrobacterium tumefaciens ti-plasmid contains an upstream activating sequence necessary for its expression in plant cells. this sequence is composed of an essential 16-bp palindrome and flanking sequences that modulate the level of expression of the ocs promoter in transgenic tobacco calli. in this study, we have used rna gel blot analysis of rna extracted from transgenic tobacco plants to show that the octopine synthas ... | 1992 | 1525561 |
| purification and some properties of l-fucose dehydrogenase from agrobacterium radiobacter and its application to the assay of bound-fucose in glycoconjugates. | l-fucose dehydrogenase was found in the cell extract of agrobacterium radiobacter and purified to homogeneity about 480-fold with 16% recovery. the molecular weight of the enzyme was approx. 64,000. the enzyme was active in the neutral ph range, unlike other l-fucose or d-arabinose dehydrogenases which are active only in the alkaline ph range. using this enzyme and alpha-l-fucosidase f-i of bacillus circulans (tsuji, y., yamamoto, k., tochikura, t., seno, t., ohkubo, y. and yamaguchi, h. (1990) ... | 1992 | 1525177 |
| construction of a cassette enabling regulated gene expression in the presence of aromatic hydrocarbons. | a high-level expression cassette has been constructed from a tol plasmid derived from pseudomonas putida carrying all cis- and trans-acting regulatory elements necessary for transcriptional gene activation in the presence of aromatic hydrocarbons such as toluene. foreign dna can be inserted at unique kpni, saci, and ecori sites 7, 13, and 15 nucleotides downstream of a ribosome binding site. the cassette, flanked by bamhi and ecori restriction sites, was inserted into a broad-host-range vector a ... | 1992 | 1513877 |
| growth inhibition and loss of virulence in cultures of agrobacterium tumefaciens treated with acetosyringone. | acetosyringone, a phenolic inducer of the virulence (vir) genes of agrobacterium tumefaciens, inhibited the growth of the nopaline-type strains t37 and c58 incubated under acidic conditions. in the course of a 6-day incubation with acetosyringone, avirulent clones were produced in different proportions by strains t37 and c58 and also by a spontaneous variant of strain c58, denominated c58f. the proportion of avirulent clones in acetosyringone-treated cultures often exceeded 50% for strains t37 a ... | 1992 | 1512200 |
| at-rich promoter elements of soybean heat shock gene gmhsp17.5e bind two distinct sets of nuclear proteins in vitro. | a 33 bp double-stranded oligonucleotide homologous to two at-rich sequences located upstream (-907 to -889 and -843 to -826) to the start of transcription of heat shock gene gmhsp17.5e of soybean stimulated transcription when placed 5' to a truncated (-140) maize adh1 promoter. the chimeric promoter was assayed in vivo utilizing anaerobically stressed sunflower tumors transformed by a pti-based vector of agrobacterium tumefaciens. nuclear proteins extracted from soybean plumules were shown to bi ... | 1992 | 1511143 |
| constitutive expression of the beta-phaseolin gene in different tissues of transgenic alfalfa does not ensure phaseolin accumulation in non-seed tissue. | phaseolin is a glycoprotein that constitutes the major storage protein in bean seeds. the phaseolin gene promoters function in a seed-specific manner. in an attempt to understand if events following transcription of the gene also contribute to the seed-specific accumulation of the phaseolin protein, we studied the effect of substituting the constitutive camv-35s promoter for the beta-phaseolin gene promoter on expression of the phaseolin gene in different plant organs. a chimeric gene consisting ... | 1992 | 1511140 |
| factors affecting the rate of t-dna transfer from agrobacterium tumefaciens to nicotiana glauca plant cells. | different factors involved in the early steps of the t-dna transfer process were studied by using a beta-glucuronidase gene (gusa) as a reporter in nicotiana glauca leaf disc transformation experiments. the levels of transient expression of the gusa gene in leaf discs infected with several strains or vir mutants correlated well with their virulence phenotype, except for virc mutants. the rate of t-dna transfer was shown to be stimulated in the case of non-oncogenic strains by the co-transfer of ... | 1992 | 1511127 |
| transcription and autoregulation of the stabilizing functions of broad-host-range plasmid rk2 in escherichia coli, agrobacterium tumefaciens and pseudomonas aeruginosa. | the broad-host-range plasmid rk2 has been shown to encode several proteins important for its maintenance within bacterial populations of a number of gram-negative bacteria. their genes are organized into two operons: parcba and pard. these operons have been proposed to be transcribed from two divergent promoters, p-parcba and p-pard, located within a sequence of approximately 150 bases. in this report we identify and characterize the sequences required for regulated transcription from these prom ... | 1992 | 1508045 |
| construction and use of agrobacterium tumefaciens binary vectors with a. tumefaciens c58 t-dna genes. | five plant morphoregulatory genes were isolated from the agrobacterium tumefaciens ti plasmid and binary plasmid vectors for plant transformation with these genes were constructed. all vectors have a similar structure with t-dna borders, rk2 origin of replication and chimeric kanamycin resistance gene for the selection of transformed plant tissues. over twenty vectors with single and combined morphoregulatory genes were constructed and their effects after tobacco tissue transformation studied. | 1992 | 1505884 |
| the t-dna-linked vird2 protein contains two distinct functional nuclear localization signals. | agrobacterium tumefaciens causes neoplastic growth in plants by transferring a piece of dna, called t-dna, into the nucleus of the plant cell. the virulence protein vird2 of a. tumefaciens is tightly linked to the t-dna and is thought to direct it to the plant genome. here we show that the vird2 protein contains two nuclear localization signals that are functional both in yeast and in plant cells. one signal is located in the n-terminal part of the protein and resembles a single-cluster-type nuc ... | 1992 | 1502156 |
| transconjugants of agrobacterium radiobacter harbouring sym genes of rhizobium galegae can form an effective symbiosis with medicago sativa. | it is known that the rhizobium galegae genomes contain megaplasmids. the suicide vector psup2111 with nifh gene of r. meliloti was introduced into the strains ciam 0703 and ciam 0711 of r. galegae inducing effective nodules on galega orientalis plants. the formation of self-transmissible megaplasmids was observed. the megaplasmid transfer into non-nodulating r. meliloti mutants resulted in partial complementation of the nodulation defect in recipient strains though only one transconjugant showed ... | 1992 | 1499987 |
| evidence that the acidic polysaccharide secreted by agrobacterium radiobacter (atcc 53271) has a seventeen glycosyl-residue repeating unit. | the extracellular anionic polysaccharide produced by the bacterium agrobacterium radiobacter (atcc 53271) contains d-galactose, d-glucose, and pyruvic acid in the molar ratio 2:15:2. analysis of the methylated polysaccharide indicated the presence of terminal, non-reducing glucosyl, 3-, 4-, 6-, 2,4-, and 4,6-linked glucosyl residues, 3-linked 4,6-o-[(s)-1-carboxyethylidene]glucosyl residues, and 3-linked galactosyl residues. partial acid hydrolysis of the methylated polysaccharide, followed by r ... | 1992 | 1499017 |
| characterization of a cell-free translation system from agrobacterium tumefaciens. | 1992 | 1486984 | |
| a nuclear localization signal and the c-terminal omega sequence in the agrobacterium tumefaciens vird2 endonuclease are important for tumor formation. | the t-dna portion of the agrobacterium tumefaciens tumor-inducing (ti) plasmid integrates into plant nuclear dna. direct repeats define the t-dna ends; transfer begins when the vird2 endonuclease produces a site-specific nick in the right-hand border repeat and attaches to the 5' end of the nicked strand. subsequent events generate linear single-stranded vird2-bound dna molecules that include the entire t-dna (t-strands). vird2 protein contains a nuclear localization signal (nls) near the c term ... | 1992 | 1465407 |
| multiple copies of virg enhance the transient transformation of celery, carrot and rice tissues by agrobacterium tumefaciens. | in an effort to improve the t-dna-mediated transformation frequency of economically important crops, we investigated the possible enhancement effect of multiple copies of virg genes contained in agrobacterium tumefaciens strains upon the transient transformation of celery, carrot and rice tissues. four days after a. tumefaciens infection, we performed histochemical beta-glucuronidase (gus) assays to determine the frequency of transient transformation of calli from celery and carrot, and explants ... | 1992 | 1463842 |
| factors influencing agrobacterium-mediated transient expression of gusa in rice. | transient expression of gus in rice (oryza sativa l.) mediated by agrobacterium tumefaciens was characterized using binary vectors containing gusa genes that express minimal (pkiwi105 and pcnl1) or no (p35s-gus-int and pcnl56) gus activity in bacteria. four-day old seedlings obtained from seeds or immature embryos of rice were cut into shoot, root, and seed remnants and inoculated with various strains of a. tumefaciens. transient gus expression events were quantitated histochemically by determin ... | 1992 | 1463839 |
| translation controls the expression level of a chimaeric reporter gene. | transcriptional and translational fusions between the reading frame of the beta-d-glucuronidase gene (gusa) and the 2' as well as the 1' promoter of mannopine synthase (mas), a tr locus of agrobacterium tumefaciens, were made. the expression of these constructs was studied in the transgenic f1 offspring of independent tobacco transformants at the protein level by assaying for gus activity and western blot analysis of the gus protein and at the steady-state mrna level. in leaves, stems and roots ... | 1992 | 1463829 |
| deletion derivatives of pagk84 and their use in the analysis of agrobacterium plasmid functions. | the 47.7-kb plasmid pagk84, present in agrobacterium radiobacter strain k84, confers production of a novel, highly specific, antiagrobacterial antibiotic called agrocin 84. strain k84 is used commercially to biocontrol crown gall caused by agrocin 84-susceptible strains of agrobacterium tumefaciens. efficient biocontrol is dependent upon production of agrocin 84 by strain k84. starting with a derivative of pagk84 containing a tn5 insertion, a series of deletion derivatives of the plasmid were is ... | 1992 | 1461939 |
| mechanism of action of cyclic beta-1,2-glucan synthetase from agrobacterium tumefaciens: competition between cyclization and elongation reactions. | we have examined some aspects of the mechanism of cyclic beta-1,2-glucan synthetase from agrobacterium tumefaciens (235-kda protein, gene product of the chvb region). the enzyme produces cyclic beta-1,2-glucans containing 17 to 23 glucose residues from udp-glucose. in the presence of added cyclic beta-1,2-glucans (> 0.5 mg/ml) (containing 17 to 23 glucose residues), the enzyme instead synthesizes larger cyclic beta-1,2-glucans containing 24 to 30 glucose residues. this is achieved by de novo syn ... | 1992 | 1459942 |
| agrobacterium tumefaciens peritonitis mimicking tuberculosis. | agrobacterium species have been previously implicated in the development of clinical disease. we report what we believe to be the first case of ascites caused by agrobacterium tumefaciens in a cirrhotic patient. since the correct diagnosis was made only after laparoscopy-guided collection of specimens from two different tissues, we suggest that agrobacterium may be an underdiagnosed pathogen in clinical situations in which tuberculosis is considered to be the cause of high-protein ascites. | 1992 | 1457664 |
| activation of a plant gene by t-dna tagging: auxin-independent growth in vitro. | a transferred dna (t-dna) tagging vector with the potential to produce dominant mutations was used with cocultured agrobacterium tumefaciens and protoplasts to tag genes involved in the action of the plant growth substance auxin. transgenic calli were selected for their ability to grow in the absence of auxin in the culture media. from one experiment, 12 calli that displayed this phenotype were recovered, of which 11 were able to regenerate into plants. in one plant studied in detail, protoplast ... | 1992 | 1455228 |
| expression of a coriander desaturase results in petroselinic acid production in transgenic tobacco. | little is known about the metabolic origin of petroselinic acid (18:1 delta 6cis), the principal fatty acid of the seed oil of most umbelliferae, araliaceae, and garryaceae species. to examine the possibility that petroselinic acid is the product of an acyl-acyl carrier protein (acp) desaturase, western blots of coriander and other umbelliferae seed extracts were probed with antibodies against the delta 9-stearoyl-acp desaturase of avocado. in these extracts, proteins of 39 and 36 kda were detec ... | 1992 | 1454797 |
| detection and enumeration of bacteria in soil by direct dna extraction and polymerase chain reaction. | in order to develop a rapid and specific detection test for bacteria in soil, we improved a method based on the polymerase chain reaction (pcr). each step of the protocol, including direct lysis of cells, dna purification, and pcr amplification, was optimized. to increase the efficiency of lysis, a step particularly critical for some microorganisms which resist classical techniques, we used small soil samples (100 mg) and various lytic treatments, including sonication, microwave heating, and the ... | 1992 | 1444380 |
| inhibition of tumor induction in tobacco by agrobacterium tumefaciens and nodulation induced by rhizobium meliloti in the presence of phenothiazines and structurally related compounds. | plasmids of agrobacterium tumefaciens and rhizobium meliloti carrying kanamycin resistance genes were eliminated from 1.4 to 0.2% of the growing bacterial cultures by promethazine and imipramine. as a result of plasmid elimination, the a. tumefaciens plasmidless isolate was not able to induce crown gall tumor on tobacco plants. the plasmidless r. meliloti strain failed to induce nodule formation on alfalfa plants. the efficiency of nodulation was decreased when the bacteria were grown in the pre ... | 1992 | 1444234 |
| molecular analysis of the reca gene of agrobacterium tumefaciens c58. | the complete nucleotide sequence of the agrobacterium tumefaciens reca gene was determined. a comparison of the translated open reading frame of the gene with other known reca sequences revealed significant sequence conservation. however, unlike its escherichia coli equivalent, a. tumefaciens reca lacks the upstream 'sos box', suggesting a different mechanism of regulation for this gene. | 1992 | 1427086 |
| expression of ti plasmid genes in monocotyledonous plants infected with agrobacterium tumefaciens. 1984. | 1992 | 1422045 | |
| the agrobacterium tumefaciens ti plasmid as a host vector system for introducing foreign dna in plant cells. 1980. | 1992 | 1422043 | |
| broad host range and promoter selection vectors for bacteria that interact with plants. | a plasmid vector, pgv910, and a derived cosmid, prg930, have been constructed. both contain the cole1 and pvs1 origins of replication and are stably maintained in escherichia coli, agrobacterium tumefaciens, and azorhizobium caulinodans ors571. they are compatible with commonly used incp cloning vectors, although pvs1 was classified as an incp plasmid, unable to replicate in e. coli (y. itoh, j.m. watson, d. haas, and t. leisinger, plasmid 11:206-220, 1984). promoter selection vectors were deriv ... | 1992 | 1421510 |
| physical map of the vitopine ti plasmid ptis4. | within the agrobacterium vitis group the vitopine strains represent a special subclass. vitopine bacteria carry ti plasmids with little or no homology with the well-characterized t-dnas of agrobacterium tumefaciens or agrobacterium rhizogenes. the 262-kb ti plasmid of the vitopine strain s4 was cloned and mapped. homology studies with the octopine ti plasmid ptiach5, the nopaline ti plasmid ptic58, and the agropine/mannopine ri plasmid prihri identified several regions of homology. the origin of ... | 1992 | 1409971 |
| agroinfection as an alternative to insects for infecting plants with beet western yellows luteovirus. | beet western yellows luteovirus, like other luteoviruses, cannot be transmitted to host plants by mechanical inoculation but requires an aphid vector, a feature that has heretofore presented a serious obstacle to the study of such viruses. in this paper we describe use of agroinfection to infect hosts with beet western yellows virus without recourse to aphids. agroinfection is a procedure for introducing a plant virus into a host via agrobacterium tumefaciens harboring a ti plasmid, which can ef ... | 1992 | 1409615 |
| isolation and characterization of the aada aminoglycoside-resistance gene from salmonella choleraesuis. | the streptomycin- and spectinomycin-resistance gene of salmonella choleraesuis was cloned and its nucleotide sequence determined. the gene is 789 bases long, encoding a protein of a predicted size of 29,353 da. the gene product inactivated streptomycin and spectinomycin by an adenylation modification. it is homologous (c. 40% total identity) to streptomycin adenylyltransferase, a 3'(9)-o-nucleotidyltransferase (aad(3')(9)), which is encoded by the aada gene in escherichia coli, agrobacterium tum ... | 1992 | 1406282 |
| altered-function mutations of the transcriptional regulatory gene virg of agrobacterium tumefaciens. | three point mutations were isolated in the agrobacterium tumefaciens virg gene by screening for vir gene expression in the absence of added phenolic inducing compounds. all three mutations were localized in the predicted amino-terminal phosphoryl receiver domain of the protein. one mutant (n54d) bypasses the requirement for vira and phenolic inducers both for transcriptional activation of all tested vir promoters and for plant tumorigenesis. this mutant also activates vir gene expression efficie ... | 1992 | 1400254 |
| functional roles assigned to the periplasmic, linker, and receiver domains of the agrobacterium tumefaciens vira protein. | vira and virg activate the agrobacterium tumefaciens vir regulon in response to phenolic compounds, monosaccharides, and acidity released from plant wound sites. vira contains an amino-terminal periplasmic domain and three cytoplasmic domains: a linker, a protein kinase, and a phosphoryl receiver. we constructed internal deletions of vira that truncate one or more domains and tested the ability of the resulting proteins to mediate environmentally responsive vir gene activation in vivo. the perip ... | 1992 | 1400253 |
| mutational analysis of essential incp alpha plasmid transfer genes traf and trag and involvement of traf in phage sensitivity. | although the broad-host-range incp plasmids can vegetatively replicate in diverse gram-negative bacteria, the development of shuttle vector systems has established that the host range for incp plasmid conjugative transfer is greater than the range of bacteria that sustain incp replicons. towards understanding incp plasmid conjugation and the connection between incp conjugation and agrobacterium tumefaciens t-dna transfer to plants, two sets of mutants were generated in the larger transfer region ... | 1992 | 1400217 |
| the orit region of the agrobacterium tumefaciens ti plasmid ptic58 shares dna sequence identity with the transfer origins of rsf1010 and rk2/rp4 and with t-region borders. | ti plasmids of agrobacterium tumefaciens are conjugal elements whose transfer is induced by certain opines secreted from crown galls. on transmissible plasmids, dna transfer initiates within a cis-acting site, the origin of conjugal transfer, or orit. we have localized an orit on the a. tumefaciens plasmid ptic58 to a region containing the conjugal transfer loci trai and traii and acc, which is the locus encoding catabolism of the two conjugal opines, agrocinopines a and b. the smallest function ... | 1992 | 1400174 |
| construction of a chimeric viral gene expressing plum pox virus coat protein. | the capsid-encoding gene of plum pox virus (ppv) was fused with the leader sequence of the coat protein mrna (cp) of tobacco mosaic virus by a novel mutagenesis technique which involves reverse transcription of minus-strand rna [synthesized by in vitro transcription of a double-stranded (ds) cdna clone], using an ad hoc synthetic oligodeoxynucleotide as primer. the resulting cdna was rendered ds and cloned into the plasmid, pbluescribe m13+. transcription of this chimeric construction produced r ... | 1992 | 1398133 |