| agrobacterium-mediated inoculation of pstvd cdnas onto tomato reveals the biological effect of apparently lethal mutations. | potato spindle tuber viroid (pstvd) mutants which contain alterations in the terminal loops of the rod-like native structure have previously been reported from our laboratory. pstvd-p contains mutations at positions 2, 4, and 6 in the left terminal loop; pstvd-r+, a sequence permutation of pstvd-r, contains the same mutations at positions 177 and 178 in the right terminal loop as pstvd-r and contains in addition a 1-nucleotide g insertion at position 176. pstvd-p, pstvd-r, and pstv-r+ were nonin ... | 1994 | 7513926 |
| autoregulation and kinetics of induction of the rhizobium phaseoli reca gene. | a fusion between the reca gene of rhizobium phaseoli and the lacz gene was constructed in vitro and cloned in a mini-tn5 transposon derivative to obtain chromosomal insertions which make it possible to quantitatively examine their transcriptional regulation in both r. phaseoli and e. coli. likewise, and by insertion of a spectinomycin-resistance gene cassette into the reca gene of r. phaseoli and subsequent marker exchange, a reca- derivative of this bacterial species has been obtained. analysis ... | 1994 | 7516490 |
| the psi operon of rhizobium leguminosarum biovar phaseoli: identification of two genes whose products are located at the bacterial cell surface. | we have delineated three short open reading frames, psia, orf-p and psib within the psi operon of rhizobium leguminosarum biovar phaseoli. psia, in a multi-copy plasmid, causes inhibition of exopolysaccharide synthesis in r. leguminosarum. in addition, the suppression of exopolysaccharide synthesis due to the multi-copy psia caused r. leguminosarum strains to stain with the dye calcofluor, a response that does not occur with wild-type strains of this species. insertions of a defective phoa gene ... | 1994 | 7517767 |
| photosynthetic symbionts of aeschynomene spp. form a cluster with bradyrhizobia on the basis of fatty acid and rrna analyses. | the relationship between photosynthetic rhizobia that nodulate 10 aeschynomene species (aeschynomene afraspera, aeschynomene denticulata, aeschynomene evenia, aeschynomene indica, aeschynomene nilotica, aeschynomene pratensis, aeschynomene rudis, aeschynomene scabra, aeschynomene schimperi, and aeschynomene sensitiva) and reference strains of the genera bradyrhizobium, rhizobium, and azorhizobium was investigated by analyzing cellular fatty acid methyl esters (fame) and 16s rrna sequences. the m ... | 1994 | 7520731 |
| rhizobium ciceri sp. nov., consisting of strains that nodulate chickpeas (cicer arietinum l.). | the taxonomic status of 16 collection strains of chickpea (cicer arietinum l.) rhizobia which were previously determined to belong to two groups (groups a and b) were compared with reference strains belonging to different genera and species of the family rhizobiaceae. we used the following taxonomic, phylogenetic, and phenotypic characteristics and approaches to study these organisms: dna homology, guanine-plus-cytosine content, restriction fragment length polymorphism of the amplified 16s-inter ... | 1994 | 7520739 |
| the structure of the o-antigenic chain of the lipopolysaccharide of rhizobium trifolii 4s. | the structure of the o-antigen chain of the lipopolysaccharide (lps) of rhizobium trifolii 4s has been determined by a combination of chemical and spectroscopic methods. the glycosyl components were found to be l-rhamnose, n-acetyl-d-glucosamine, and n-acetyl-d-mannosamine in 3:1:1 molar proportion, as determined by gas chromatography and gas chromatography-mass spectrometry of alditol acetate and persilylated (r)-2-hydroxybutyl glycoside derivatives. the linkage positions and configurations of ... | 1994 | 7520834 |
| the nodulation-signaling protein nodo from rhizobium leguminosarum biovar viciae forms ion channels in membranes. | the secreted nodulation-signaling protein nodo was purified from the supernatant of cultures of rhizobium leguminosarum biovar viciae. the native protein has a m(r) of approximately 67,000, suggesting that it exists as a dimer since the dna sequence predicts a m(r) of 30,002. pure nodo protein had no protease, pectinase, or cellulase activity, and no binding was observed to lipooligosaccharide nodulation factors. although nodo is relatively hydrophilic, it appeared to insert into liposomes and w ... | 1994 | 7524090 |
| expression of tfx and sensitivity to the rhizobial peptide antibiotic trifolitoxin in a taxonomically distinct group of alpha-proteobacteria including the animal pathogen brucella abortus. | three phylogenetically distinct groups within the alpha-proteobacteria which differ in trifolitoxin sensitivity are described. trifolitoxin sensitivity was found in strains of agrobacterium, brucella, mycoplana, ochrobactrum, phyllobacterium, rhodobacter, rhodopseudomonas, rhodospirillum, and rhizobium. strains of agrobacterium, brucella, phyllobacterium, rhizobium, and rhodospirillum were capable of producing trifolitoxin upon conjugal transfer of tfxabcdefg. | 1994 | 7527627 |
| cloning of the hsp70 (dnak) genes from rhizobium meliloti and pseudomonas cepacia: phylogenetic analyses of mitochondrial origin based on a highly conserved protein sequence. | the genes for hsp70 (or dnak) have been cloned and sequenced from rhizobium meliloti and pseudomonas cepacia, two bacterial species belonging to the alpha- and beta-subdivisions of gram-negative proteobacteria, respectively. on the basis of global alignment of hsp70 proteins, several sequence signatures have been identified that are distinctive of mitochondrial homologs and gram-negative proteobacteria on the one hand and the chloroplasts and cyanobacteria on the other. detailed phylogenetic ana ... | 1994 | 7528198 |
| splicing of the rola transcript of agrobacterium rhizogenes in arabidopsis. | the rola gene encoded on the ri plasmid a4 of agrobacterium rhizogenes is one of the transferred (tl-dna) genes involved in the pathogenesis of hairy-root disease in plants. the function of the 100-amino acid protein product of rola is unknown, although its expression causes physiological and developmental alterations in transgenic plants. the rola gene of a. rhizogenes contains an intron in its untranslated leader region that has features typical of plant pre-messenger rna introns. transcriptio ... | 1994 | 7528444 |
| the groesl operon of agrobacterium tumefaciens: evidence for heat shock-dependent mrna cleavage. | the heat shock response of the groesl operon of agrobacterium tumefaciens was studied at the rna level. the operon was found to be activated under heat shock conditions and transcribed as a polycistronic mrna that contains the groes and groel genes. after activation, the polycistronic mrna appeared to be cleaved between the groes and groel genes and formed two monocistronic mrnas. the groes cleavage product appeared to be unstable and subjected to degradation, while the groel cleavage product ap ... | 1995 | 7530710 |
| analysis of dna flanking the xlnb locus of streptomyces lividans reveals genes encoding acetyl xylan esterase and the rna component of ribonuclease p. | nucleotide sequencing revealed the gene (axea) encoding acetyl xylan esterase (axea) downstream from xlnb in the streptomyces lividans dna insert of plasmid piaf42. axea consists of a catalytic- and a substrate-binding domain separated by a gly-rich linker. the n terminus showed no significant homology with published esterases and acetyl xylan esterases, but some homology was found with the xylanases xyla and xyld and the nodb protein of rhizobium species which is involved in the biosynthesis of ... | 1995 | 7533741 |
| a phylogenetic analysis of micro-organisms isolated from subsurface environments. | three methods were used to provide information on the identity and phylogenetic relatedness of 19 aerobic, chemoheterotrophic bacteria isolated from topsoil and deep subsurface sediments at a site in south carolina. these methods were (i) analysis of selected physiological traits, (ii) restriction endonuclease analysis (rea) of genomic dna, and (iii) analysis of 16s ribosomal rna sequences. when the 16s rrna sequences were compared with those for 12 standard strains, two topsoil isolates and six ... | 1995 | 7536094 |
| lipopolysaccharide core structures in rhizobium etli and mutants deficient in o-antigen. | lipopolysaccharide (lps) is a major component of the bacterial outer membrane, and for rhizobium spp. has been shown to play a critical role in the establishment of an effective nitrogen-fixing symbiosis with a legume host. many genes required for o-chain polysaccharide synthesis are in the lps alpha region of the ce3 genome; this region may also carry lps genes required for core oligosaccharide synthesis. the lpss from several strains mutated in the alpha region were isolated, and their mild ac ... | 1995 | 7538123 |
| hypoxic induction of human vascular endothelial growth factor expression through c-src activation. | angiogenesis, the formation of new microvasculature by capillary sprouting, is crucial for tumour development. hypoxic regions of solid tumours produce the powerful and directly acting angiogenic protein vegf/vpf (vascular endothelial growth factor/vascular permeability factor). we now investigate the signal transduction pathway involved in hypoxic induction of vegf expression. hypoxia is known to induce a tyrosine kinase cascade that results in the activation of nitrogen-fixation genes in rhizo ... | 1995 | 7540725 |
| localization of peanut (arachis hypogaea) root lectin (pra ii) on root surface and its biological significance. | the glucose-specific peanut root lectin, pra ii, is localized on the surface of 7-day-old peanut seedling root and in root cortical parenchymatous cells. the lectin is eluted from intact roots upon washing with buffer containing glucose. rabbit erythrocytes bind to the root surface and the cortical cells; the binding is inhibited by antibodies raised against pra ii, peanut-specific rhizobium cells and by glucose. lipopolysaccharides isolated from host-specific rhizobium strain inhibit the haemag ... | 1995 | 7540901 |
| isolation and characterization of ropa homologous genes from rhizobium leguminosarum biovars viciae and trifolii. | ropa encodes a 36-kda outer membrane protein of rhizobium leguminosarum bv. viciae strain 248 which constitutes the low-m(r) part of antigen group iii (r.a. de maagd, i.h.m. mulders, h.c.j. canter cremers, b.j.j. lugtenberg, j. bacteriol. 174:214-221, 1992). we observed that genes homologous to ropa are present in strain 248 as well as in other r. leguminosarum strains, and we describe the cloning and characterization of two of these genes. sequencing of a 2.2-kb bg/ii fragment from r. leguminos ... | 1995 | 7545151 |
| the effect of ph and oxygen concentration on the formation of 3-ketodisaccharides by agrobacterium tumefaciens. | the further optimization of 3-ketodisaccharide formation with sucrose, leucrose and iso maltulose was studied with special regard to ph and oxygen concentration in the reaction mixture with resting cells of agrobacterium tumefaciens. it was found that the optimal ph values for the highest reaction rate and highest yield were different as the ph affected the stability of the 3-keto derivatives formed. a ph shift to 5.0 clearly reduced the enzymatic degradation of the 3-keto derivatives thus stabi ... | 1995 | 7546608 |
| genomic heterogeneity of strains nodulating chickpeas (cicer arietinum l.) and description of rhizobium mediterraneum sp. nov. | the genetic diversity of chickpea strains was studied by using 30 isolates obtained from nodules on chickpeas growing in uninoculated fields over a wide geographic range. the following taxonomic approaches were used: dna-dna relatedness analysis, restriction fragment length polymorphism analysis of the amplified 16s ribosomal dna (rdna) intergenic spacer (igs), and total 16s rrna sequence analysis. the division of chickpea-infective strains into two major phylogenetic groups (groups a and b) tha ... | 1995 | 7547282 |
| bradyrhizobium liaoningense sp. nov., isolated from the root nodules of soybeans. | seventeen strains of extra-slowly growing (esg) soybean rhizobia isolated from root nodules of glycine soja and glycine max growing in five provinces (liaoning, heilongjiang, shanxi, hubei, and anhui) in the people's republic of china were compared with 48 reference strains belonging to the genera bradyrhizobium, rhizobium, and agrobacterium by performing a numerical analysis of 191 phenotypic features. our results showed that all of the esg strains examined clustered closely in the genus bradyr ... | 1995 | 7547289 |
| substrate specificity and kinetic studies of nodulation protein nodl of rhizobium leguminosarum. | all lipo-chitin oligosaccharides identified from rhizobium leguminosarum carry an o-acetyl moiety on c6 of the nonreducing terminal n-acetylglucosamine residue. previously, we have shown that purified nodl protein, using acetyl-coa as acetyl donor, in vitro acetylates n-acetylglucosamine, chitin oligosaccharides, and lipo-chitin oligosaccharides. in this paper, the enzymatic properties and substrate specificity of nodl protein were analyzed, using a spectrophotometric assay to quantify nodl tran ... | 1995 | 7548024 |
| highly insect-resistant transgenic tobacco plants containing both b.t. and cpti genes. | the cowpea trypsin inhibitor (cpti) gene was synthesized according to its cdna sequence using dna synthesizer and confirmed by dna sequencing. the cpti gene and modified bacillus thuringiensis (b.t.) delta-endotoxin gene were cotransformed to tobacco explants mediated by agrobacterium tumefaciens. the integrations of b.t and cpti genes were confirmed by pcr and southern hybridization. three kinds of transgenic plants were obtained: (1) containing cpti gene, (2) containing b.t gene, (3) containin ... | 1995 | 7548766 |
| a 200 bp region of the pea enod12 promoter is sufficient for nodule-specific and nod factor induced expression. | enod12 is one of the first nodulin genes expressed upon inoculation with rhizobium and also purified nod factors are able to induce enod12 expression. the enod12 gene family in pea (pisum sativum) has two members. a cdna clone representing psenod12a [26] and a psenod12b genomic clone [7] have been previously described. the isolation and characterization of a psenod12a genomic clone is presented in this paper. by using a vicia hirsuta-agrobacterium rhizogenes transformation system it is shown tha ... | 1995 | 7548827 |
| vsenod5, vsenod12 and vsenod40 expression during rhizobium-induced nodule formation on vicia sativa roots. | we isolated enod5, enod12 and enod40 homologues from vicia sativa and studied their expression pattern during rhizobium-induced nodule formation. comparison of the vsenod40 nucleotide sequence with the pea, soybean and alfalfa enod40 sequences showed that the sequences contain two conserved regions, called region i and region ii. comparison of all the potential open reading frames (orfs) showed that all the five different enod40 clones encode a highly conserved small polypeptide of 12 or 13 amin ... | 1995 | 7548828 |
| transfer of non-t-dna portions of the agrobacterium tumefaciens ti plasmid ptia6 from the left terminus of tl-dna. | we introduced a plant selection marker, nptii, to the left of border a in the agrobacterium ti plasmid ptia6. infection of tobacco leaf discs with the modified agrobacterium strain gave rise to kanamycin-resistant calli which grew in a hormone-dependent manner. southern hybridization analysis of dna isolated from four transformants indicated initiation of dna transfer at or near border a and absence of t-dna sequences. these results demonstrate that dna transfer events starting at a left border ... | 1995 | 7548833 |
| electrotransformation of agrobacterium. | | 1995 | 7550732 |
| rhizobium meliloti lacking mosa synthesizes the rhizopine scyllo-inosamine in place of 3-o-methyl-scyllo-inosamine. | the rhizobium meliloti rm220-3 mos locus producing the rhizopine scyllo-inosamine (si) in nodules is shown to consist of three orfs (orf1, mosb and mosc) arranged in an operon structure. this differs from the r. meliloti l5-30 mos locus, which produces 3-o-methyl-scyllo-inosamine (3-o-msi), by the complete absence of mosa. the deletion covers a region of 1235 nt and includes the entire mosa gene as well as the sequence both upstream and downstream. as a result, rm220-3 mos orf1 shares a 5' regio ... | 1995 | 7551036 |
| beta-glucuronidase (gus) transposons for ecological and genetic studies of rhizobia and other gram-negative bacteria. | a series of transposons are described which contain the gusa gene, encoding beta-glucuronidase (gus), expressed from a variety of promoters, both regulated and constitutive. the regulated promoters include the tac promoter which can be induced by iptg, and nifh promoters which are symbiotically activated in legume nodules. one transposon contains gusa with a strong shine-dalgarno translation initiation context, but no promoter, and thus acts as a promoter-probe transposon. in addition, a gus ope ... | 1995 | 7551037 |
| the ntrbc genes of azospirillum brasilense are part of a nifr3-like-ntrb-ntrc operon and are negatively regulated. | a cosmid able to complement the nif- and nitrate-dependent growth phenotypes of the azospirillum brasilense mutant fp9 was isolated from a genomic library of the wild-type strain fp2. a 6-kb dna region was sequenced and showed two open reading frames (orfs) identified as the ntrb and ntrc genes. an orf1 located upstream from the ntrb gene and coding for a 36-kda polypeptide showed similarity to the nifr3 gene of rhodobacter capsulatus and the orf1 of rhizobium leguminosarum, both located upstrea ... | 1995 | 7553451 |
| characterization of the cmch genes of nocardia lactamdurans and streptomyces clavuligerus encoding a functional 3'-hydroxymethylcephem o-carbamoyltransferase for cephamycin biosynthesis. | sequencing of orf10 (gene cmch) of the nocardia lactamdurans cephamycin gene cluster proved that it encodes a protein with a deduced molecular mass of 57,149 da. this protein showed significant similarity to the putative o-carbamoyltransferases (o-cases) encoded by the nodu genes of rhizobium fredii and bradyrhizobium japonicum, involved in the synthesis of nodulation factors. the carbamoyl-phosphate (cp)-binding amino-acid sequence of human otcase is conserved in the cmch product. a similar cmc ... | 1995 | 7557411 |
| new gentamicin-resistance and lacz promoter-probe cassettes suitable for insertion mutagenesis and generation of transcriptional fusions. | a set of antibiotic-resistance and promoter-probe cassettes suitable for insertion mutagenesis and generation of transcriptional fusions was constructed. the cassettes contain the aacc1 gene of transposon tn1696 conferring resistance to gentamicin in a large variety of gram- and gram+ bacteria. in addition to the antibiotic-resistance gene, a promoterless escherichia coli lacz gene was included in the cassettes, allowing the determination of the transcriptional activity at the insertion site. th ... | 1995 | 7557413 |
| the insertion sequence element isrm2011-2 belongs to the is630-tc1 family of transposable elements and is abundant in rhizobium meliloti. | the insertion sequence (is) element isrm2011-2 of rhizobium meliloti (rm) is characterized by 19-bp imperfect terminal inverted repeats (three mismatches) and a size of 1053 bp. upon transposition, isrm2011-2 generates a putative target duplication of 2 bp. isrm2011-2 carries two major overlapping open reading frames (orfa and b) with a coding capacity of 135 and 201 amino acids (aa), respectively. a potential translational frameshifting window (5'-aaaaaaag) is located in the overlapping region ... | 1995 | 7557479 |
| cloning, sequencing, and phenotypic analysis of laf1, encoding the flagellin of the lateral flagella of azospirillum brasilense sp7. | azospirillum brasilense can display a single polar flagellum and several lateral flagella. the a. brasilense sp7 gene laf1, encoding the flagellin of the lateral flagella, was isolated and sequenced. the derived protein sequence is extensively similar to those of the flagellins of rhizobium meliloti, agrobacterium tumefaciens, bartonella bacilliformis, and caulobacter crescentus. an amino acid alignment shows that the flagellins of these bacteria are clustered and are clearly different from othe ... | 1995 | 7559324 |
| identification of rhizobium-specific intergenic mosaic elements within an essential two-component regulatory system of rhizobium species. | analysis of the dna regions upstream of the phosphoenolpyruvate carboxykinase gene (pcka) in rhizobium meliloti and rhizobium sp. strain ngr234 identified an open reading frame which was highly homologous to the agrobacterium tumefaciens chromosomal virulence gene product chvi. a second gene product, 500 bp downstream of the chvi-like gene in r. meliloti, was homologous to the a. tumefaciens chvg protein. the homology between the r. meliloti and a. tumefaciens genes was confirmed, because the r. ... | 1995 | 7559334 |
| the hypbfcde operon from rhizobium leguminosarum biovar viciae is expressed from an fnr-type promoter that escapes mutagenesis of the fnrn gene. | pea (pisum sativum l.) bacteroids produced by rhizobium leguminosarum bv. viciae upm791 synthesize a membrane-bound (nife) hydrogenase which oxidizes h2 arising from the nitrogen fixation process in root nodules. synthesis of the active enzyme requires the products of the structural genes hupsl and an array of accessory proteins from at least 15 additional genes, including the gene cluster hypabfcde, likely involved in nickel metabolism. unlike the hupsl genes, which are expressed only in symbio ... | 1995 | 7559356 |
| involvement of nods in n-methylation and nodu in 6-o-carbamoylation of rhizobium sp. ngr234 nod factors. | although rhizobium sp. ngr234 and rhizobium fredii usda257 share many traits, dysfunctional nodsu genes in the latter prohibit nodulation of leucaena species. accordingly, we used r. fredii transconjugants harboring the nods and nodu genes of ngr234 to study their role in the structural modification of the lipo-oligosaccharide nod factors. differences between the nod factors mainly concern the length of the oligomer (three to five glucosamine residues in usda257 and five residues only in ngr234) ... | 1995 | 7559434 |
| low-molecular-weight succinoglycan is predominantly produced by rhizobium meliloti strains carrying a mutated exop protein characterized by a periplasmic n-terminal domain and a missing c-terminal domain. | the membrane topology of the rhizobium meliloti 2011 exop protein involved in polymerization and export of succinoglycan was analysed by translational fusions of lacz and phoa reporter genes to the exop gene. based on this analysis, the exop protein could be divided into an n-terminal domain mainly located in the periplasmic space and a c-terminal domain located in the cytoplasm. whereas the c-terminal domain of exop is characterized by a potential nucleotide-binding motif, the n-terminal exop d ... | 1995 | 7565082 |
| [comparative susceptibility of ochrobactrum anthropi, agrobacterium tumefaciens, alcaligenes faecalis, alcaligenes denitrificans subsp. denitrificans, alcaligenes denitrificans subsp. xylosidans and bordetella bronchiseptica against 35 antibiotics including 17 beta-lactams]. | ochrobactrum anthropi, formerly known as "achromobacter sp." or cdc group vd has been isolated from water, hospital environment (antiseptic solutions, dialysis fluids ... ). o. anthropi is a gram negative, motile, strictly aerobic, oxydase positive and non-fermentative bacteria with a strong urease activity. the susceptibility of 13 strains of o. anthropi was determined by agar diffusion method and compared to those of type strains of agrobacterium tumefaciens, alcaligenes faecalis, alcaligenes ... | 1995 | 7567111 |
| nodulating strains of rhizobium loti arise through chromosomal symbiotic gene transfer in the environment. | rhizobia were isolated from nodules off a stand of lotus corniculatus established with a single inoculant strain, icmp3153, 7 years earlier in an area devoid of naturalized rhizobium loti. the isolates showed diversity in growth rate, spe i fingerprint of genomic dna, and hybridization pattern to genomic dna probes. the 19% of isolates that grew at the same rate as strain icmp3153 were the only isolates that had the same fingerprint as strain icmp3153. sequencing of part of the 16s rrna gene of ... | 1995 | 7568057 |
| protein crosslinking studies suggest that rhizobium meliloti c4-dicarboxylic acid transport protein d, a sigma 54-dependent transcriptional activator, interacts with sigma 54 and the beta subunit of rna polymerase. | rhizobium meliloti c4-dicarboxylic acid transport protein d (dctd) activates transcription by a form of rna polymerase holoenzyme that has sigma 54 as its sigma factor (referred to as e sigma 54). dctd catalyzes the atp-dependent isomerization of closed complexes between e sigma 54 and the dcta promoter to transcriptionally productive open complexes. transcriptional activation probably involves specific protein-protein interactions between dctd and e sigma 54. interactions between sigma 54-depen ... | 1995 | 7568201 |
| construction and properties of cloning vectors based on a 7.2-kb rhizobium meliloti cryptic plasmid. | cloning vectors (pfd1001, pfd1192, pfd1194, and pfd1212) were constructed by extension of the host range of a 7.2-kb rhizobium meliloti cryptic plasmid (prm1132f) with the cole1-based plasmids, pbr322, pacyc177, pacyc 184, psup301, or phc179; mobilization was facilitated by introduction of the orit region from prk2, a broad-host-range plasmid. the vector plasmids transferred readily into a wide range of gram-negative bacteria and had relatively low copy number in r. meliloti; two constructs, pfd ... | 1995 | 7568470 |
| species limits in rhizobium populations that nodulate the common bean (phaseolus vulgaris). | evolutionary genetic relationships among 146 bean-nodulating rhizobium strains, including 94 field isolates from three localities in colombia and 36 strains from mexico, were examined by multilocus enzyme electrophoresis and restriction fragment length polymorphism analysis of a pcr-amplified 260-bp segment of the 16s rrna gene. seventy-five electrophoretic types (ets), corresponding to multilocus enzyme genotypes, were identified, including a genotypically diverse group of 18 ets in colombia th ... | 1995 | 7574588 |
| expression vectors for the use of eukaryotic luciferases as bacterial markers with different colors of luminescence. | an easy way to identify microorganisms is to provide them with gene markers that confer a unique phenotype. several genetic constructions were developed to use eukaryotic luciferase genes for bacterial tagging. the firefly and click bettle luciferase genes, luc and lucor, respectively, were cloned under constitutive control and regulated control from different transcriptional units driven by p1, lambda pr, and ptrc promoters. comparison of the expression of each gene in escherichia coli cells fr ... | 1995 | 7574604 |
| pcr detection of ti and ri plasmids from phytopathogenic agrobacterium strains. | a universal primer set (vcf/vcr) for pcr analysis based on the sequences of the virc operon located on ti and ri plasmids was designed to detect these plasmids from phytopathogenic agrobacterium strains. with the vcf (sequence, 5'-atcatttgtagcgact-3') and vcr (sequence, 5'-agctcaaacctgcttc-3') primer set, dna fragments of 730 bp in length were amplified from cell lysates of 10 rhizogenic and 65 tumorigenic agrobacteria. dna sequencing and southern hybridization analysis confirmed that the amplif ... | 1995 | 7574623 |
| cloning of nod gene regions from mesquite rhizobia and bradyrhizobia and nucleotide sequence of the nodd gene from mesquite rhizobia. | nitrogen-fixing symbiosis between bacteria and the tree legume mesquite (prosopis glandulosa) is important for the maintenance of many desert ecosystems. genes essential for nodulation and for extending the host range to mesquite were isolated from cosmid libraries of rhizobium (mesquite) sp. strain hw17b and bradyrhizobium (mesquite) sp. strain hw10h and were shown to be closely linked. all of the cosmid clones of rhizobia that extended the host range of rhizobium (parasponia) sp. strain ngr234 ... | 1995 | 7574650 |
| synthesis of phytohormones by plant-associated bacteria. | the plant hormones, auxins and cytokinins, are involved in several stages of plant growth and development such as cell elongation, cell division, tissue differentiation, and apical dominance. the biosynthesis and the underlying mechanism of auxins and cytokinins action are subjects of intense investigation. not only plants but also microorganisms can synthesize auxins and cytokinins. the role of phytohormone biosynthesis by microorganisms is not fully elucidated: in several cases of pathogenic f ... | 1995 | 7576148 |
| conformation and dynamics of a cyclic (1-->2)-beta-d-glucan. | a molecular modelling and nuclear magnetic resonance spectroscopic study was performed in order to gain insight into the conformational preferences of cyclosophoroheptadecaose. mm3 molecular mechanics calculations predicted a non-symmetric conformer with a small cavity of 3.7 a diameter as the lowest energy form. molecular dynamics simulations gave insight into the dynamics of the free cyclosophoroheptadecaose and also supported the results of molecular mechanics calculations. a fair agreement w ... | 1995 | 7577817 |
| substrate-induced inactivation of a crippled beta-glucosidase mutant: identification of the labeled amino acid and mutagenic analysis of its role. | the beta-glucosidase from agrobacterium sp. catalyzes the hydrolysis of beta-glucosides via a covalent alpha-d-glucopyranosyl-enzyme intermediate involving glu358. hydrolysis of 2,4-dinitrophenyl beta-d-glucopyranoside by the low activity glu358asp mutant of agrobacterium beta-glucosidase is accompanied by time-dependent inactivation of the enzyme. through kinetic studies, labeling, and sequence analysis, inactivation is shown to be a consequence of the occasional (1 time in 1100) attack of tyr2 ... | 1995 | 7578060 |
| identification of the acid/base catalyst in agrobacterium faecalis beta-glucosidase by kinetic analysis of mutants. | the catalytic mechanism of the retaining beta-glucosidase (abg) from agrobacterium faecalis involves a double-displacement process in which an alpha-glucosyl-enzyme intermediate is formed with general acid catalytic assistance and then hydrolyzed with general base assistance. glu170 was identified as an important residue, possibly the acid/base catalyst, on the basis of sequence alignments. this glutamate is conserved in almost all enzymes in family 1 of glycoside hydrolases. detailed pre-steady ... | 1995 | 7578061 |
| rice scutellum induces agrobacterium tumefaciens vir genes and t-strand generation. | for successful transformation of a plant by agrobacterium tumefaciens it is essential that the explant used in cocultivation has the ability to induce agrobacterium tumour-inducing (ti) plasmid virulence (vir) genes. here we report a significant variation in different tissues of indica rice (oryza sativa l. cv. co43) in their ability to induce agrobacterium tumefaciens vir genes and t-strand generation, using explants preincubated in liquid murashige and skoog (ms) medium. an analysis of rice le ... | 1995 | 7579158 |
| site-directed mutagenesis of the enhancer region of the 780 gene promoter of t-dna. | potential regulatory sequences within the enhancer-like region of the 780 gene promoter (agrobacterium tumefaciens t-dna) were identified by site-directed mutagenesis. transcriptional activity of the mutated promoter was analyzed by s1 nuclease mapping of rna from crown gall tumors of sunflower incited using a t-dna-based vector. variability in expression levels were minimized by the use of an internal reference gene and the pooling of at least 200 tumors per construct tested. this approach iden ... | 1995 | 7579171 |
| the complete hrp gene cluster of pseudomonas syringae pv. syringae 61 includes two blocks of genes required for harpinpss secretion that are arranged colinearly with yersinia ysc homologs. | pseudomonas syringae pv. syringae 61 contains a 25-kb hrp cluster that is sufficient to elicit the hypersensitive response (hr) in nonhost plants. previous studies have shown that mutations in complementation groups viii, ix, and xi in the hrp cluster abolished the ability of the bacterium to cause the hr. the sequence of a 3.7-kb smai-ssti fragment covering groups viii and ix now reveals five open reading frames (orfs) in the same transcript, designated as hrpu, hrpw, hrpo, hrpx, and hrpy, and ... | 1995 | 7579617 |
| pleiotropic effects of regulatory ros mutants of agrobacterium radiobacter and their interaction with fe and glucose. | four exo mutants of agrobacterium radiobacter, defective in the synthesis of acidic exopolysaccharide were complemented by a gene from that species, which is similar to the transcriptional regulator, ros, of a. tumefaciens. it was confirmed that this a. radiobacter gene, which we term rosar, like ros, repressed its own transcription as well as that of virc and vird, two loci involved in tumorigenesis. the sequence of rosar suggested that it might bind to a transition metal and its repressor abil ... | 1995 | 7579618 |
| regulation of agrobacterium tumefaciens virulence gene expression: isolation of a mutation that restores virgd52e function. | expression of agrobacterium tumefaciens virulence (vir) genes is controlled by vira, virg, and a plant inducer. isolation of two constitutive mutants of the transcriptional activator virg, virgn54d, and virgi106l, that support vir gene expression in a vira independent manner has previously been reported. characterization of virgn54d by several groups showed considerable variation in its ability to activate vir gene transcription. in this study we demonstrate that these differences can be account ... | 1995 | 7579624 |
| growth and storage of agrobacterium. | | 1995 | 7581656 |
| transformation of soybean (glycine max) via agrobacterium tumefaciens and analysis of transformed plants. | | 1995 | 7581657 |
| agrobacterium-mediated transformation of potato genotypes. | | 1995 | 7581658 |
| agrobacterium-mediated transformation of soft fruit rubus, ribes, and fragaria. | | 1995 | 7581659 |
| high-frequency and efficient agrobacterium-mediated transformation of arabidopsis thaliana ecotypes "c24" and "landsberg erecta" using agrobacterium tumefaciens. | | 1995 | 7581660 |
| transformation protocols for broadleaved trees. | | 1995 | 7581661 |
| agrobacterium virulence. | | 1995 | 7581662 |
| agrobacterium-mediated antibiotic resistance for selection of somatic hybrids. the genus lycopersicon as a model system. | | 1995 | 7581663 |
| histochemical gus analysis. | | 1995 | 7581664 |
| fluorometric gus analysis for transformed plant material. | | 1995 | 7581665 |
| the detection of neomycin phosphotransferase activity in plant extracts. | | 1995 | 7581666 |
| the plant oncogenes rola, b, and c from agrobacterium rhizogenes. effects on morphology, development, and hormone metabolism. | | 1995 | 7581667 |
| quantifying polyamines in agrobacterium rhizogenes strains and in ri plasmid transformed cells. | | 1995 | 7581668 |
| iaa analysis in transgenic plants. | | 1995 | 7581669 |
| quantifying phytohormones in transformed plants. | | 1995 | 7581670 |
| manipulating photosynthesis in transgenic plants. | | 1995 | 7581671 |
| gene activation by t-dna tagging. | | 1995 | 7581672 |
| agrobacterium tumefaciens chemotaxis protocols. | | 1995 | 7581673 |
| assessing cadmium partitioning in transgenic plants. | | 1995 | 7581674 |
| overexpression of chloroplastic cu/zn superoxide dismutase in plants. | | 1995 | 7581675 |
| agroinfection. | | 1995 | 7581676 |
| t-dna transfer to maize plants. | | 1995 | 7581677 |
| use of cosmid libraries in plant transformations. | | 1995 | 7581678 |
| regulation of agrobacterium gene manipulation. | | 1995 | 7581679 |
| effect of acetosyringone on growth and oncogenic potential of agrobacterium tumefaciens. | | 1995 | 7581680 |
| electroporation protocols for agrobacterium. | | 1995 | 7581682 |
| binary ti plasmid vectors. | | 1995 | 7581683 |
| leaf disk transformation. | | 1995 | 7581684 |
| agrobacterium-mediated transformation of protoplasts from oilseed rape (brassica napus l.). | | 1995 | 7581685 |
| agrobacterium-mediated transformation of stem disks from oilseed rape (brassica napus l.). | | 1995 | 7581686 |
| peanut transformation. | | 1995 | 7581687 |
| simple cultural tests for identification of agrobacterium biovars. | | 1995 | 7581688 |
| study of the organization of the genomes of escherichia coli, brucella melitensis and agrobacterium tumefaciens by insertion of a unique restriction site. | tn5map, a tn5 derivative containing the 18 bp i-scei site, was delivered from a rp4-mobilizable, rk6-derived suicide vector to escherichia coli hb101, brucella melitensis and agrobacterium tumefaciens c58, which all lack natural i-scei sites in their genomes. digestion of the dna from tn5map-containing strains and analysis by pulsed-field gel electrophoresis (pfge) revealed that these derivatives contained a single transposon insertion. these digests also gave direct and independent proof for th ... | 1995 | 7582002 |
| poly-beta-hydroxybutyrate (phb) biosynthetic genes in rhizobium meliloti 41. | genes encoding beta-ketothiolase (phaa), acetoacetyl-coa reductase (phab) and phb-synthase (phac) from r. meliloti 41, together with a fourth gene, referred to as orf1, presumed to be involved in phb biosynthesis, have been cloned and sequenced. phaa, phab and orf1 were identified by heterologous hybridization on a cosmid library, while phac was isolated by cloning the transposon-tagged fragment from a r. meliloti phb- tn5 mutant. phaa and phab were functionally expressed in escherichia coli whi ... | 1995 | 7582015 |
| agrobacterium radiobacter and related organisms take up fructose via a binding-protein-dependent active-transport system. | washed cells of agrobacterium radiobacter prepared from a fructose-limited continuous culture (d 0.045 h-1) transported d(-)[u-14c]fructose in a linear manner for up to 4 min at a rate several-fold higher than the rate of fructose utilization by the growing culture. d(-)[u-14c]fructose transport exhibited a high affinity for fructose (kt < 1 microm) and was inhibited to varying extents by osmotic shock, by the uncoupling agent carbonyl cyanide p-trifluoromethoxyphenylhydrazone, and by unlabelled ... | 1995 | 7582021 |
| low temperature growth, freezing survival, and production of antifreeze protein by the plant growth promoting rhizobacterium pseudomonas putida gr12-2. | the plant growth promoting rhizobacterium pseudomonas putida gr12-2 was originally isolated from the rhizosphere of plants growing in the canadian high arctic. here we report that this bacterium was able to grow and promote root elongation of both spring and winter canola at 5 degrees c, a temperature at which only a relatively small number of bacteria are able to proliferate and function. in addition, the bacterium survived exposure to freezing temperatures, i.e., -20 and -50 degrees c. in an e ... | 1995 | 7585354 |
| detection of rhizobium meliloti cells in field soil and nodules by polymerase chain reaction. | a genetically marked rhizobium meliloti strain, r692, was prepared by insertion of a 1.7-kb dna segment from tn903 between the nifhdk and fixabc genes in the nod megaplasmid. this dna was used as a marker, detectable by polymerase chain reaction (pcr), for the specific identification of bacteria in soil samples and alfalfa nodules. this detection technique was tested by applying different titres of the marked strain to field plots seeded with alfalfa. samples of soil and nodules were assayed for ... | 1995 | 7585359 |
| strain-specific fingerprints of rhizobium galegae generated by pcr with arbitrary and repetitive primers. | strain-specific genomic patterns of rhizobium galegae were generated by pcr using both arbitrary and repetitive (box, eric and rep) primers. the identification of the strains was achieved also by rflp analysis. however, the pcr genomic fingerprinting has significant advantages: it is not only simpler and faster, but it is also much more discriminative because it deals with the full bacterial genome and not only with parts of it as is the case with rflp. in addition, both kinds of pcr fingerprint ... | 1995 | 7592135 |
| the dnakj operon of agrobacterium tumefaciens: transcriptional analysis and evidence for a new heat shock promoter. | the dnakj operon of agrobacterium tumefaciens was cloned and sequenced and was found to be highly homologous to previously analyzed dnakj operons. transcription of this operon in a. tumefaciens was stimulated by heat shock as well as by exposure to ethanol and hydrogen peroxide. there were two transcripts representing the dnakj operon: one containing the dnak and dnaj genes and the second containing only the dnak gene. primer extension analysis indicated that transcription started from the same ... | 1995 | 7592349 |
| in vitro sulfotransferase activity of nodh, a nodulation protein of rhizobium meliloti required for host-specific nodulation. | early stages of nodulation involve the exchange of signals between the bacterium and the host plant. bacterial nodulation (nod) genes are required for rhizobium spp. to synthesize lipooligosaccharide morphogens, termed nod factors. the common nod genes encode enzymes that synthesize the factor core structure, which is modified by host-specific gene products. here we show direct in vitro evidence that rhizobium meliloti nodh, a host-specific nodulation gene, catalyzes the transfer of sulfate from ... | 1995 | 7592390 |
| rhizobium nodi and nodj proteins play a role in the efficiency of secretion of lipochitin oligosaccharides. | thin-layer chromatographic analysis of extracts of d-[1-14c]glucosamine-labelled rhizobia was used to analyze the effects of nodi, nodj, and nodt on secretion of lipochitin oligosaccharide (lco) signal molecules. secretion was analyzed by comparing quantities of radiolabelled lcos present in the cellular and spent growth medium fractions. a second rapid and sensitive method was introduced to estimate the secreted lco fractions by using d-[1-14c]glucosamine-labelled cells grown in medium suppleme ... | 1995 | 7592394 |
| mass spectrometric analysis of chitin oligosaccharides produced by rhizobium nodc protein in escherichia coli. | a system for studying the in vivo activity of rhizobium nodc protein in escherichia coli has been developed. using thin-layer chromatography, high-performance liquid chromatography, and mass spectrometry, we show that in this system r. leguminosarum bv. viciae nodc protein directs the synthesis of chitinpentaose, chitintetraose, chitintriose, and two as yet unidentified modified chitin oligosaccharides. | 1995 | 7592395 |
| a novel cyclic beta-1,2-glucan mutant of rhizobium meliloti. | the periplasmic cyclic beta-1,2-glucans produced by bacteria within the rhizobiaceae family provide functions during hypo-osmotic adaptation and plant infection. in rhizobium meliloti, these molecules are highly modified with phosphoglycerol and succinyl substituents, and it is possible that the anionic character of these glucans is important for their functions. in the present study, we have used a thin-layer chromatographic screening method to identify a novel r. meliloti mutant specifically b ... | 1995 | 7592408 |
| aerobic and anaerobic regulation in rhodobacter sphaeroides 2.4.1: the role of the fnrl gene. | in rhodobacter sphaeroides 2.4.1, the cellular requirements for 5-aminolevulinic acid (ala) are in part regulated by the level of ala synthase activity, which is encoded by the hema and hemt genes. under standard growth conditions, only the hema gene is transcribed, and the level of ala synthase activity varies in response to oxygen tension. the presence of an fnr consensus sequence upstream of hema suggested that oxygen regulation of hema expression could be mediated, in part, through a homolog ... | 1995 | 7592416 |
| sequence and mutational analysis of a tartrate utilization operon from agrobacterium vitis. | the grapevine is the natural host of the tumorigenic bacterium agrobacterium vitis. most of the a. vitis isolates can use tartrate, an unusually abundant compound in grapevine. the nopaline strain, ab4, contains a 170-kb conjugative plasmid (ptrab4) encoding tartrate utilization. a 5.65-kb ptrab4 region which enables non-tartrate-utilizing agrobacterium tumefaciens to grow on tartrate was sequenced and mutagenized with the transcriptional fusion transposon tn5-uida1. this dna fragment contains f ... | 1995 | 7592429 |
| structure and functional analysis of a marine bacterial carotenoid biosynthesis gene cluster and astaxanthin biosynthetic pathway proposed at the gene level. | a carotenoid biosynthesis gene cluster for the production of astaxanthin was isolated from the marine bacterium agrobacterium aurantiacum. this cluster contained five carotenogenic genes with the same orientation, which were designated crtw, crtz, crty, crti, and crtb. the stop codons of individual crt genes except for crtb overlapped the start codons of the following crt genes. escherichia coli transformants carrying the erwinia uredovora carotenoid biosynthesis genes provide suitable substrate ... | 1995 | 7592436 |