| rhizobium meliloti fixghi sequence predicts involvement of a specific cation pump in symbiotic nitrogen fixation. | we present genetic and structural analyses of a fix operon conserved among rhizobia, fixghi from rhizobium meliloti. the nucleotide sequence of the operon suggests it may contain a fourth gene, fixs. adjacent open reading frames of this operon showed an overlap between tga stop codons and atg start codons in the form of an atga motif suggestive of translational coupling. all four predicted gene products contained probable transmembrane sequences. fixg contained two cysteine clusters typical of i ... | 1989 | 2536685 |
| a novel exopolysaccharide can function in place of the calcofluor-binding exopolysaccharide in nodulation of alfalfa by rhizobium meliloti. | we have found that r. meliloti strain rm1021, which is known to synthesize a calcofluor-binding exopolysaccharide (eps i), also has a cryptic capacity to synthesize a second exopolysaccharide (eps ii). structural analysis of eps ii has shown that it differs in many respects from eps i. genetic analysis indicates that eps ii synthesis requires the products of at least seven loci on the second symbiotic megaplasmid of r. meliloti, and is induced by a mutation, expr101, which causes increased trans ... | 1989 | 2537152 |
| coordinate regulation and sensory transduction in the control of bacterial virulence. | genes and operons that encode bacterial virulence factors are often subject to coordinate regulation. these regulatory systems are capable of responding to various environmental signals that may be encountered during the infectious cycle. for some pathogens, proteins that mediate sensory transduction and virulence control are similar to components of other bacterial information processing systems. understanding the molecular mechanisms governing global regulation of pathogenicity is essential fo ... | 1989 | 2537530 |
| sequence determination and characterization of the replicator region in the tumor-inducing plasmid ptib6s3. | the replicator region of the 195-kilobase-pair (kb) tumor-inducing plasmid ptib6s3 was previously identified by isolation of a 6.8-kb miniplasmid (b.p. koekman, p.j.j. hooykaas, and r.a. schilperoort, plasmid 7:119-132, 1982). this miniplasmid was joined to cole1-based vectors and subjected to mutagenesis. the resulting mutant plasmids were examined for their ability to replicate autonomously in agrobacterium tumefaciens. it was found that a 4.2-kb region was sufficient for displaying replicatio ... | 1989 | 2537824 |
| the vird operon of agrobacterium tumefaciens ti plasmid encodes a dna-relaxing enzyme. | the vird locus of agrobacterium tumefaciens ti plasmid encodes functions necessary for endonucleolytic cleavage of transferred dna (t-dna) prior to its transfer to plant cells. for the overproduction of the vird proteins in escherichia coli a tac-vird operon fusion was constructed. a significant increase in the accumulation of vird proteins was observed in a lon protease-deficient e. coli host. the presence of an overlapping open reading frame (orf) upstream of the vird1 coding sequence had a ne ... | 1989 | 2541431 |
| identification of bradyrhizobium nod genes involved in host-specific nodulation. | three loci important for soybean nodulation by bradyrhizobium japonicum were delimited by tn5 mutagenesis on a 5.3-kilobase ecori fragment adjacent to the nodabc genes. results of hybridization studies suggested that this region is conserved in bradyrhizobium species but absent in all rhizobium species. lacz translational fusions of two of the loci contained in this region were found to be inducible by host-produced flavonoid chemicals via a mechanism requiring a functional nodd gene product. a ... | 1989 | 2542223 |
| symbiotic properties of rhizobia containing a flavonoid-independent hybrid nodd product. | a hybrid nodd gene consisting of 75% of the nodd1 gene of rhizobium meliloti at the 5' end and 27% of the nodd gene of rhizobium trifolii at the 3' end activates the six tested inducible nod promoters of rhizobium leguminosarum, r. trifolii, or r. meliloti to maximal levels, even in the absence of flavonoids. in strains containing such a constitutive activating nodd gene, transcription of nod genes started at the same site as in flavonoid-induced strains containing a wild-type nodd gene. in cont ... | 1989 | 2544568 |
| isr1, a transposable dna sequence resident in rhizobium class iv strains, shows structural characteristics of classical insertion elements. | isr1 is a small transposable element, identified in rhizobium class iv strains by its high frequent mutagenic insertion into plasmid rp4. hybridization studies showed that isr1 is present in, multiple copies in rhizobium class iv strains. nucleotide sequence analysis revealed that isr1 has a length of 1260 bp and is characterized by perfect inverted repeats of 13 nucleotides followed by a stretch of 28/29 nucleotides with imperfect homology. the insertion under study generated a target site dupl ... | 1989 | 2544911 |
| identification of insertion sequence element is427 in ptit37 plasmid dna of an agrobacterium tumefaciens t37 isolate. | the isolation and characterization of an insertion sequence (is) element, is427, from agrobacterium tumefaciens t37 is described. is427 is present in three nonidentical copies on the ptit37 plasmid. the copy that was isolated through transposition on the entrapment vector pucd800 contains at its ends a 16-bp imperfect inverted repeat and generates a 2-bp duplication of the target dna. is427 does not show homology with previously characterized is elements of a. tumefaciens, based on hybridization ... | 1989 | 2544912 |
| plasmid localization and mapping of two azospirillum brasilense loci that affect exopolysaccharide synthesis. | two azospirillum brasilense loci that correct rhizobium meliloti exob and exoc mutants for exopolysaccharide (eps) synthesis have been identified previously (k. w. michiels, j. vanderleyden, a. p. van gool, e. r. signer, j. bacteriol., 1988b). a. brasilense exo mutants produce eps of lower molecular weight than the wild type strain. here, we show by hybridization that these exo loci are located on a 90-mda plasmid in a. brasilense sp7. in four other azospirillum strains but not in a. lipoferum s ... | 1989 | 2544914 |
| the rhizobium meliloti host range nodq gene encodes a protein which shares homology with translation elongation and initiation factors. | the rhizobium meliloti nod region iib is involved in host-range determination: (i) the presence of region iib is necessary for transfer of alfalfa root hair curling ability to rhizobium leguminosarum biovar trifolii; (ii) a mutation in region iib extends the r. meliloti infection host range to vicia sativa nigra; (iii) dominance of r. meliloti nod genes over r. leguminosarum biovar viciae nod genes is abolished by mutations in region iib. the nucleotide sequence of this region has been determine ... | 1989 | 2546009 |
| analysis of c4-dicarboxylate transport genes in rhizobium meliloti. | a 5.1 kbp dna fragment was isolated which complemented c4-dicarboxylate transport mutants (dct) of rhizobium meliloti. characterization of this fragment by subcloning, transposon mutagenesis, and complementation analysis revealed three loci, designated dcta, dctb, and dctd. tnphoa-generated alkaline phosphatase fusions to dcta suggested that this gene encodes the structural transport protein and allowed the determination of its direction of transcription. analysis of the fusions in various mutan ... | 1989 | 2546011 |
| nucleotide sequence, evolutionary origin and biological role of a rearranged cytokinin gene isolated from a wide host range biotype iii agrobacterium strain. | a dna fragment with homology to the cytokinin (ipt) gene from biotype i agrobacterium tumefaciens strain ach5 was cloned from the ti plasmid of the wide host range biotype iii agrobacterium strain tm-4 and sequenced. the fragment contains an intact ipt coding sequence. however, the 3' non-coding region of this ipt gene is rearranged due to a 0.9 kb deletion fusing it to the 3' coding region of the neighbouring gene 6a, most of which was found to be deleted. the tm-4 ipt gene is strongly related ... | 1989 | 2546041 |
| omegon-km: a transposable element designed for in vivo insertional mutagenesis and cloning of genes in gram-negative bacteria. | to combine the features of the omega interposons with the advantages of in vivo transposition mutagenesis, we have constructed an artificial transposon, called omegon-km. the omegon-km transposon is carried on the plasmid pjff350 which can be conjugally mobilized into a broad range of gram-negative bacteria. omegon-km is flanked, in inverted orientation, by synthetic 28-bp repeats derived from the ends of is1. in addition, each end of omegon-km has the very efficient transcription and translatio ... | 1989 | 2546859 |
| implication of nifa in regulation of genes located on a rhizobium meliloti cryptic plasmid that affect nodulation efficiency. | we examined the contribution of a cryptic plasmid, prmegr4b, to the nodulation of medicago sativa by strain gr4 of rhizobium meliloti. a 905-base-pair psti dna fragment in prmegr4b was found to hybridize dna of the r. meliloti fixa promoter region as a probe. sequence analysis of the psti fragment showed a 206-base-pair region displaying high homology with the dna upstream of the rna start points of the p1 and p2 symbiotic promoters. putative nif promoter consensus sequences were conserved in th ... | 1989 | 2546913 |
| human placental 17 beta-hydroxysteroid dehydrogenase is homologous to nodg protein of rhizobium meliloti. | the amino acid sequence of human placental 17 beta-hydroxysteroid dehydrogenase (17 beta-oh-steroid dehydrogenase) was found to be similar to that of the nodg protein of rhizobium meliloti. the computer-based comparison score is 11.5 sd higher than that obtained with 2500 comparisons of randomized sequences of these proteins. the probability of getting such a score by chance is 6 x 10(-31). 17 beta-oh-steroid dehydrogenase is also similar to klebsiella aerogenes ribitol dehydrogenase and escheri ... | 1989 | 2547159 |
| microbial epimerization of 1-deoxynojirimycin to 1-deoxymannojirimycin. | | 1989 | 2547743 |
| direct selection for curing and deletion of rhizobium plasmids using transposons carrying the bacillus subtilis sacb gene. | we have constructed derivatives of the transposon tn5 carrying the mob site (orit) of plasmid rp4, and an npti-sacb-sacr cassette [ried and collmer, gene 57 (1987) 239-246]. the mob site, in conjunction with the antibiotic-resistance markers carried on the transposons, allows identification of transposon inserts in cryptic plasmids by mobilisation to other strains. the sacb-sacr genes allow direct selection for the loss or curing of plasmids, because only strains which no longer contain an activ ... | 1989 | 2548927 |
| rhizobium leguminosarum exopolysaccharide mutants: biochemical and genetic analyses and symbiotic behavior on three hosts. | ten independently generated mutants of rhizobium leguminosarum biovar phaseoli cfn42 isolated after tn5 mutagenesis formed nonmucoid colonies on all agar media tested and lacked detectable production of the normal acidic exopolysaccharide in liquid culture. the mutants were classified into three groups. three mutants harbored tn5 insertions on a 3.6-kilobase-pair ecori fragment and were complemented to have normal exopolysaccharide production by cosmids that shared an ecori fragment of this size ... | 1989 | 2549002 |
| mutational analysis of the virion-sense genes of maize streak virus. | insertion and deletion mutagenesis of the two virion-sense genes, v1 and v2, of maize streak virus (msv) prevents symptomatic infections following agrobacterium-mediated 'agroinoculation' of maize seedlings. these genes code for an mr 10900 protein and for coat protein, respectively. mutants containing insertions or deletions in the coat protein gene, v2, were able to replicate to low levels, producing dsdna although virion ssdna was not detected and symptoms were not observed. hence, unlike the ... | 1989 | 2550570 |
| sequence and distribution of is866, a novel t region-associated insertion sequence from agrobacterium tumefaciens. | we have identified a new insertion sequence, is866, located in the auxin synthesis gene ta iaah of tm4, a wide host range biotype iii octopine/cucumopine type agrobacterium tumefaciens strain with two t regions on its tumor-inducing (ti) plasmid, ta, and tb. is866 is 2716 bp long, has inverted repeats of 27 bp with three mismatches, and generates 8-bp direct repeats upon integration. in addition to is866, ptitm4 carries two copies of a related element, is867, associated with ta and tb, respectiv ... | 1989 | 2550985 |
| comparative study of the symbiotic plasmid dna in free living bacteria and bacteroids of rhizobium leguminosarum. | the symbiotic plasmid (psym) dna present in bacteroids of strain rcr1001 of rhizobium leguminosarum biovar viceae has been compared qualitatively and quantitatively with that present in free living bacteria by hybridization experiments with appropriate probes. a decrease in the relative amount of psym dna was observed in bacteroids as compared to bacteria. no rearrangements of the symbiotically expressed psym borne genes were detected in bacteroids. | 1989 | 2551770 |
| characterization of conjugal transfer functions of agrobacterium tumefaciens ti plasmid ptic58. | physical characterization of 13 transposon tn5 insertions within the agrocinopine-independent, transfer-constitutive ti plasmid ptic58trac identified three separate loci essential for conjugation of this nopaline/agrocinopine a + b-type ti plasmid. complementation analysis with relevant subcloned dnas indicated that the three physically separated blocks of conjugal genes constitute distinct complementation groups. two independent tn5 insertions within the wild-type, agrocinopine-dependent, repre ... | 1989 | 2551885 |
| aromatic aminotransferase activity and indoleacetic acid production in rhizobium meliloti. | bacterial indoleacetic acid (iaa) production, which has been proposed to play a role in the rhizobium-legume symbiosis, is a poorly understood process. previous data have suggested that iaa biosynthesis in rhizobium meliloti can occur through an indolepyruvate intermediate derived from tryptophan by an aminotransferase activity. to further examine this biosynthetic pathway, the aromatic aminotransferase (aat) activity of rhizobium meliloti 102f34 (f34) was characterized. at least four proteins w ... | 1989 | 2551887 |
| identification and sequence analysis of the rhizobium meliloti dcta gene encoding the c4-dicarboxylate carrier. | transposon tn5-induced c4-dicarboxylate transport mutants of rhizobium meliloti 2011 which could be complemented by cosmid prmsc121 were subdivided into two classes. class i mutants (rms37 and rms938) were defective in symbiotic c4-dicarboxylate transport and in nitrogen fixation. they were mutated in the structural gene dcta, which codes for the c4-dicarboxylate carrier. class ii mutants (rms11, rms16, rms17, rms24, and rms31) expressed reduced activity in symbiotic c4-dicarboxylate transport a ... | 1989 | 2551890 |
| characterization of rhizobium phaseoli sym plasmid regions involved in nodule morphogenesis and host-range specificity. | two nodulation regions from the symbiotic plasmid (psym) of rhizobium phaseoli ce-3 were identified. the two regions were contained in overlapping cosmids psm927 and psm991. these cosmids, in a r. phaseoli psym-cured strain background, induced ineffective nodules on phaseolus vulgaris roots. transconjugants of rhizobium meliloti harbouring psm991 induced nodule-like structures on bean roots, suggesting that this cosmid contains host-range determinants. analysis of deletions and insertional mutat ... | 1989 | 2552255 |
| the nifa gene product from rhizobium leguminosarum biovar trifolii lacks the n-terminal domain found in other nifa proteins. | the nifa gene has been identified between the fixx and nifb genes in the clover microsymbiont rhizobium leguminosarum biovar trifolii (r.i. bv. trifolii) strain anu843. expression of the nifa gene is induced in the symbiotic state and site-directed mutagenesis experiments indicate that nifa expression is essential for symbiotic nitrogen fixation. interestingly, the predicted r.i. bv. trifolii nifa protein lacks an n-terminal domain that is present in the homologous proteins from r.i. bv. viciae, ... | 1989 | 2552256 |
| cloning a genomic region required for a high-affinity iron-uptake system in rhizobium meliloti 1021. | a collection of transposon-induced mutants of rhizobium meliloti 1021 defective in siderophore-mediated iron assimilation were obtained and classified as biosynthetic, transport or regulatory. several of the mutations were cloned and the adjacent sequences were used to acquire complementing dna from the wild type. a single genomic region of about 35kb complemented all of the mutants deficient in production of the siderophore. | 1989 | 2552263 |
| genes involved in lipopolysaccharide production and symbiosis are clustered on the chromosome of rhizobium leguminosarum biovar viciae vf39. | four mutants of rhizobium leguminosarum biovar viciae vf39 altered in lipopolysaccharide (lps) synthesis were isolated upon random tn5 mutagenesis. these mutants produced matt colonies on ty medium and showed autoagglutination and loss of motility. on sodium dodecyl sulfate-polyacrylamide gels, they lacked a slow-migrating carbohydrate band, corresponding to the complete lps (lpsi). all four mutants formed small white nodules on vicia hirsuta. these nodules were infected but showed no nitrogen-f ... | 1989 | 2553672 |
| high-frequency t-dna-mediated gene tagging in plants. | an insertion element [transferred dna (t-dna)], transferred by soil agrobacteria into the nuclear genome of plants, was used for induction of gene fusions in arabidopsis thaliana, nicotiana tabacum, and nicotiana plumbaginifolia. a promoterless aph(3')ii (aminoglycoside phosphotransferase ii) reporter gene was linked to the right end of the t-dna and transformed into plants along with a plasmid replicon and a selectable hygromycin-resistance gene. transcriptional and translational reporter gene ... | 1989 | 2554318 |
| expression of the adenyl cyclase-encoding gene (cya) of rhizobium meliloti f34: existence of two cya genes? | to gain insight into the role of cyclic amp (camp) in gram-negative soil bacteria, we have studied the expression of an adenyl cyclase-encoding gene 'cya' of rhizobium meliloti f34. in both escherichia coli and bradyrhizobium japonicum, the gene is expressed from a promoter(s) contained on a 2.6-kb fragment of the cloned insert, which may indicate the presence of a functional 'cya' promoter or the coincidental presence of sequences which can function as promoters in these two species. the study ... | 1989 | 2555267 |
| characterization and nucleotide sequence of a novel gene fixw upstream of the fixabc operon in rhizobium leguminosarum. | on the rhizobium leguminosarum pre sym plasmid, fixabc and a novel gene fixw were identified upstream of the regulatory gene nifa. the molecular masses of fixabc, 29, 44 and 50 kda respectively, were estimated by polyacrylamide gel electrophoresis (page) and of fixw, 25 kda, by page and nucleotide sequencing. hybridization studies using bacteroid mrna as a probe showed that fixabc is one operon which can be transcribed independently of fixw. nucleotide sequencing revealed that both fixw and fixa ... | 1989 | 2555670 |
| cyclic diguanylic acid and cellulose synthesis in agrobacterium tumefaciens. | the occurrence of the novel regulatory nucleotide bis(3',5')-cyclic diguanylic acid (c-di-gmp) and its relation to cellulose biogenesis in the plant pathogen agrobacterium tumefaciens was studied. c-di-gmp was detected in acid extracts of 32p-labeled cells grown in various media, and an enzyme responsible for its formation from gtp was found to be present in cell-free preparations. cellulose synthesis in vivo was quantitatively assessed with [14c]glucose as a tracer. the organism produced cellul ... | 1989 | 2556370 |
| covalently bound vird2 protein of agrobacterium tumefaciens protects the t-dna from exonucleolytic degradation. | we show that upon induction of agrobacterium tumefaciens, free linear double-stranded t-dna molecules as well as the previously described t-strands are generated from the ti plasmid. a majority of these molecules are bound to a protein. we show that this protein is the product of the virulence gene vird2. this protein was found to be attached to the 5' terminus of processed t-dna at the right border and to the rest of the ti plasmid at the left border. the protein remnant after pronase digestion ... | 1989 | 2556703 |
| sequences near the termini are required for transposition of the maize transposon ac in transgenic tobacco plants. | deletion derivatives of the maize transposable element activator (ac) were constructed in vitro and inserted into a kanamycin resistance gene. these constructions were then introduced into tobacco protoplasts derived from plants previously transformed with ac. the ability of each deletion derivative to excise was measured by whether or not kanamycin-resistant tobacco calli were recovered. this allowed us to determine the length of dna present at each terminus that is required to respond to the p ... | 1989 | 2556710 |
| conserved function in nicotiana tabacum of a single drosophila hsp70 promoter heat shock element when fused to a minimal t-dna promoter. | to demonstrate the extent of evolutionary conservation in the mechanism of induction of heat shock genes between plants and animals, the minimal sequence from the drosophila hsp70 promoter sufficient to confer heat shock inducible transcription in tobacco was determined. segments of the hsp70 promoter were fused to a minimal promoter of the t-dna indole-3-acetamide hydrolase (iaah) gene, in a chimaeric gene fusion to a neomycin phosphotransferase (npt ii) reporter gene. sequences bearing one or ... | 1989 | 2559318 |
| transposable elements for efficient manipulation of a wide range of gram-negative bacteria: promoter probes and vectors for foreign genes. | we describe here the construction and use of a series of modified transposons based on the insertion sequence is1. like their parent, omegon-km [fellay et al., gene 76 (1989) 215-226], these elements permit efficient insertional mutagenesis of a variety of gram-negative bacteria. the presence of a functional pbr322 origin of replication within the transposable element facilitates subsequent cloning of the mutated gene. the omegon-km system was previously shown to function in pseudomonas putida, ... | 1989 | 2559879 |
| carbon metabolism and catabolite repression in rhizobium spp. | | 1989 | 2561263 |
| structural and functional stability of foreign genes in transgenic tobacco plants. | the drosophila genomic fragment dm111 and the selectable dominant nptii gene were transferred via a ti-vector into tobacco plants in order to check the structural and functional stability of transgenes in plants and their progeny. southern blot analyses clearly showed that transgenes were integrated intact and did not suffer from any gross dna rearrangements. contrary to this structural stability, not all of the transgenic plants and their offspring displayed the original and stable expression o ... | 1989 | 2561278 |
| transposon mutagenesis and complementation of the fructokinase gene in rhizobium leguminosarum biovar trifolii. | transposon tn5 was used to generate a fructokinase mutation in rhizobium leguminosarum biovar trifolii bal. the section of the genome containing tn5 was cloned into the ecori site of the vector phc79 and isolated by direct selection on medium containing kanamycin and tetracycline. total ecori digestion was used to obtain a single fragment containing tn5 and flanking dna sequences. the flanking dna was used as a probe to isolate an intact fructokinase gene from a plafr1 cosmid clone bank of the p ... | 1989 | 2561289 |
| model-building of fnr and fixk dna-binding domains suggests a basis for specific dna recognition. | the dna-binding c-terminal domains of the regulatory proteins fnr from escherichia coli and fixk from rhizobium meliloti have been modelled on the basis of their homologies to the cap protein from e. coli. residues glu181, thr182 and arg185 of cap, which are exposed residues of the dna-recognition helix alpha f, are conserved in fnr and fixk. however, arg180 and gly184 are substituted by val and ser respectively in fnr. we propose that this valine makes a van der waals' contact with the first th ... | 1989 | 2561529 |
| additional nodulation genes on the sym plasmid of rhizobium leguminosarum biovar viciae. | a rhizobium leguminosarum biovar viciae strain lacking a 40 kb dna region of the sym plasmid prl1ij to the left (3' side) of gene node failed to nodulate vicia sativa plants. therefore this dna region was investigated for the presence of additional nodulation genes. complementation experiments indicated that the dna region to the left (3' side) of node is functionally homologous between r. leguminosarum bv. viciae and r. leguminosarum bv. trifolii. in this dna region, three nodulation genes were ... | 1989 | 2562395 |
| a comparative study of tam3 and ac transposition in transgenic tobacco and petunia plants. | transposition of the anthirrinum majus tam3 element and the zea mays ac element has been monitored in petunia and tobacco plants. plant vectors were constructed with the transposable elements cloned into the leader sequence of a marker gene. agrobacterium tumefaciens-mediated leaf disc transformation was used to introduce the transposable element constructs into plant cells. in transgenic plants, excision of the transposable element restores gene expression and results in a clearly distinguishab ... | 1989 | 2562396 |
| cell-autonomous behavior of the rolc gene of agrobacterium rhizogenes during leaf development: a visual assay for transposon excision in transgenic plants. | we describe a genetic switch based on the ac transposable element of maize and the rolc gene of agrobacterium rhizogenes, a dominant gene, which has pleiotropic effects on plant growth and morphology. moreover, rolc gene expression under the control of the 35s cauliflower mosaic virus promoter decreases chlorophyll content in transgenic tobacco plants. chlorophyll is a visible cell-autonomous marker, and it is shown here that the reduction in chlorophyll content caused by the rolc gene product a ... | 1989 | 2562512 |
| production of root hair deformation factors by rhizobium meliloti nodulation genes in escherichia coli: hsnd (nodh) is involved in the plant host-specific modification of the nodabc factor. | the role of the hsnd (nodh) gene in the determination of the host-specific nodulation ability of rhizobium meliloti was studied by expressing the common nodulation genes (nodabc) with or without the hsnd gene in escherichia coli and testing for biological activity on various leguminous plants. in this way, four categories of plants were established. upon infection with e. coli carrying the nodabc construct, root hair deformation (had) was detected on clovers while the hsnd gene was additionally ... | 1989 | 2562755 |
| induction and growth properties of carrot roots with different complements of agrobacterium rhizogenes t-dna. | single and multiple infections of carrot discs were carried out with agrobacterium strains harbouring different segments of pri1855 tl-dna cloned in the binary vector bin 19 and with a strain carrying the tr-dna from the same ri plasmid. roots induced by the various co-inoculations were cultured and their growth patterns were followed. abundant roots could be induced by tl-dna rol genes a, b and c as a single insert (rola + b + c) and by rolb alone provided an extended segment beyond its 5' non- ... | 1989 | 2562759 |
| cis-acting regulatory elements controlling temporal and organ-specific activity of nopaline synthase promoter. | regulatory elements controlling temporal and organ-specific expression of the nopaline (nos) gene were identified by analyzing deletion mutants of the promoter. as observed in cultured cells, the tata box element was required for efficient promoter function and the 29 bp upstream promoter region between -130 and -101 was necessary for the nos promoter activity in various vegetative organs. this 29 bp region includes ten nucleotides of a potential z-dna-forming sequence (z element) and eight nucl ... | 1989 | 2563151 |
| rhizobium meliloti 1021 has three differentially regulated loci involved in glutamine biosynthesis, none of which is essential for symbiotic nitrogen fixation. | we have cloned and characterized three distinct rhizobium meliloti loci involved in glutamine biosynthesis (glna, glnii, and glnt). the glna locus shares dna homology with the glna gene of klebsiella pneumoniae, encodes a 55,000-dalton monomer subunit of the heat-stable glutamine synthetase (gs) protein (gsi), and complemented an escherichia coli glna mutation. the glnii locus shares dna homology with the glnii gene of bradyrhizobium japonicum and encodes a 36,000-dalton monomer subunit of the h ... | 1989 | 2563998 |
| isolation, characterization, and complementation of rhizobium meliloti 104a14 mutants that lack glutamine synthetase ii activity. | the glutamine synthetase (gs)-glutamate synthase pathway is the primary route used by members of the family rhizobiaceae to assimilate ammonia. two forms of glutamine synthetase, gsi and gsii, are found in rhizobium and bradyrhizobium species. these are encoded by the glna and glnii genes, respectively. starting with a rhizobium meliloti glna mutant as the parent strain, we isolated mutants unable to grow on minimal medium with ammonia as the sole nitrogen source. for two auxotrophs that lacked ... | 1989 | 2570058 |
| regulation of glutamine synthetase ii activity in rhizobium meliloti 104a14. | most rhizobia contain two glutamine synthetase (gs) enzymes: gsi, encoded by glna, and gsii, encoded by glnii. we have found that wsu414, a rhizobium meliloti 104a14 glutamine auxotroph derived from a glna parental strain, is an ntra mutant. the r. meliloti glnii promoter region contains dna sequences similar to those found in front of other genes that require ntra for their transcription. no gsii was found in the glna ntra mutant, and when a translational fusion of glnii to the escherichia coli ... | 1989 | 2570059 |
| restriction fragment length polymorphism analysis of rhizobium galegae strains. | total dna of various rhizobium galegae strains representing different geographical origins, and taxonomic divergence was digested with three restriction enzymes separately, southern blotted, and hybridized with six heterologous probes. the sequence divergences for different pairwise comparisons were calculated from proportions of conserved hybridizing fragments. the unweighted pair group method was used to group the strains. the symbiotic common nod and nifhdk probes used were highly conserved a ... | 1989 | 2571610 |
| site-specific mutagenesis identifies amino acid residues critical in prohormone processing. | peptide hormones are generally synthesized as inactive higher mol. wt precursors. processing of the prohormone into biologically active peptides by specific proteolytic cleavages occurs most often at pairs of basic amino acids but also at single arginine residues. to study the role of protein secondary structure in this process, we used site-directed mutagenesis to modify the predicted secondary structure around the cleavage sites of human prosomatostatin and monitored the processing of the prec ... | 1989 | 2573512 |
| glutamine synthetase ii in rhizobium: reexamination of the proposed horizontal transfer of dna from eukaryotes to prokaryotes. | we have determined the dna sequence of a rhizobium meliloti gene that encodes glutamine synthetase ii (gsii). the deduced amino acid sequence was compared to that of bradyrhizobium japonicum gsii and those of various plant and mammalian glutamine synthetases (gs) in order to evaluate a proposal that the gene for this enzyme was recently transferred from plants to their symbiotic bacteria. there is 83.6% identity between the r. meliloti and b. japonicum proteins. the bacterial gsii proteins avera ... | 1989 | 2575672 |
| purification and partial amino acid sequence of a glutamyl-trna synthetase from rhizobium meliloti. | a glutamyl-trna synthetase has been purified to homogeneity from rhizobium meliloti, using reversed-phase chromatography as the last step. amino acid sequencing of the amino-terminal region of the enzyme indicates that it contains a single polypeptide, whose molecular weight is about 54,000, as judged by sds-gel electrophoresis. the primary structures of the amino-terminus region and of an internal peptide obtained by cleavage of the enzyme with cnbr have similarities of 58 and 48% with regions ... | 1989 | 2590524 |
| agrobacterium radiobacter and cdc group ve-2 bacteremia. | agrobacterium radiobacter and cdc group ve-2 are rare human pathogens. the simultaneous infection with both of these bacteria in an immunocompromised host is reported. review of the ucla microbiology laboratory records revealed one additional case of a. radiobacter bacteremia and two additional cases of cdc group ve-2 bacteremia over a 3-year period. the clinical experience with these organisms is reviewed. both organisms are opportunistic pathogens with a predilection for patients with foreign ... | 1989 | 2591169 |
| the agrobacterium tumefaciens virc1 gene product binds to overdrive, a t-dna transfer enhancer. | in agrobacterium tumefaciens, a cis-active 24-base-pair sequence adjacent to the right border of the t-dna, called overdrive, stimulates tumor formation by increasing the level of t-dna processing. recent results from our laboratory have suggested that the virc operon which enhances t-dna processing probably does so because the virc1 protein interacts with overdrive (n. toro, a. datta, m. yanofsky, and e. w. nester, proc. natl. acad. sci. usa 85:8558-8562, 1988). we report here the purification ... | 1989 | 2592351 |
| developmental and environmental regulation of a phenylalanine ammonia-lyase-beta-glucuronidase gene fusion in transgenic tobacco plants. | a 1.1-kilobase promoter fragment of the bean (phaseolus vulgaris l.) phenylalanine ammonia-lyase (ec 4.3.1.5) gene pal2 was translationally fused to the beta-glucuronidase reporter gene and transferred to tobacco by agrobacterium tumefaciens-mediated leaf disk transformation. the distribution of beta-glucuronidase activity in these transgenic plants is very similar to that of endogenous pal2 transcripts in bean, with very high levels in petals; marked accumulation in anthers, stigmas, roots, and ... | 1989 | 2594769 |
| fast-growing root nodule bacteria produce a novel polyamine, aminobutylhomospermidine. | polyamines in various root nodule bacteria including bradyrhizobium japonicum, rhizobium fredii, r. leguminosarum, r. meliloti and r. loti were identified by capillary gas chromatography. homospermidine was the polyamine present in highest concentration in all the rhizobia tested. in addition to putrescine and homospermidine, fast-growing type of rhizobial cells contained a novel polyamine, aminobutylhomospermidine, nh2(ch2)4nh(ch2)4nh(ch2)4nh2. the unusual tetraamine was not found in the cells ... | 1989 | 2597153 |
| construction of a gene bank of rhizobium leguminosarum rld 164. | the total genomic dna of r. leguminosarum rld164 (trp, sms, azi) was cloned in the ecor1 site of the wide host and conjugally transferable cosmid vector plafr1. the average insert size in the gene clones of the bank was found to be 21.3 kb. the strain r. leguminosarum rld7 (leu-1) was employed as recepient to conjugally transfer and thus isolate the complementary leu+ allele carrying clones from the gene bank. | 1989 | 2606538 |
| signal structure of the cis-acting element recognized by virg protein, a positive regulator in agrobacterium. | virg protein is known to be the positive regulator for vir genes of ri and ti plasmids in agrobacterium. to investigate the cis-acting element recognized by virg, we have determined the transcriptional start points of the vir genes on ri plasmid (pria4b). from the analysis of the upstream sequences, it has been found that the sequences generally similar to 5'tg(a/t)aa(c/t)3' appear in phase with an 11-base pair interval, and that the -35 and -10 regions of the promoters are located nearly in the ... | 1989 | 2608465 |
| polysaccharides production by rhizobium phaseoli and the typing of their excreted anionic polysaccharides. | the pattern of polysaccharide production amongst strains of rhizobium phaseoli appear very varied: some strains produce anionic exopolysaccharides (eps) as major polysaccharides (eps) as major polymer without any other product, but most strains exhibit greater polysaccharide diversity. apart from eps they excrete capsular polysaccharides (cps) and accumulate poly-beta-hydroxybutyric acid (phb) and/or glycogen in their cells. the latter can then be used as c-sources for further synthesis of eps a ... | 1989 | 2612887 |
| binding-protein-dependent sugar transport by agrobacterium radiobacter and a. tumefaciens grown in continuous culture. | binding-protein-dependent sugar transport has been investigated in agrobacterium radiobacter and a. tumefaciens. a. radiobacter contained two high-affinity glucose-binding proteins (gbp1 and gbp2) that additionally bound d-galactose (kd 0.26 microm) and d-xylose (kd 0.04 microm) respectively and were involved in the transport of these sugars. partial sequencing of gbp1 and gbp2 showed that gbp2 exhibited significant homology with both the arabinose-binding protein (abp) and the galactose-binding ... | 1989 | 2614377 |
| single and multiple mutations affecting properties of the regulatory gene nodd of rhizobium. | nodd of rhizobium leguminosarum has two regulatory properties: it autoregulates and, in cells grown with specific flavonoids, activates other nod genes. we isolated mutations in nodd affecting one or both properties. those abolishing autoregulation and nod gene induction were at the 5' end of nodd, as were those which only affected autoregulation. mutations affecting nod gene activation are at the 3' end of nodd. eleven mutations in this region of nodd were isolated: some had little effect on th ... | 1989 | 2615655 |
| the nodl gene from rhizobium leguminosarum is homologous to the acetyl transferases encoded by laca and cyse. | the predicted protein sequence of the nodl gene from rhizobium leguminosarum was screened against translations of the genbank dna sequence database. a very strong homology was found to laca, which encodes thiogalactoside transferase; homology between nodl and the cyse gene product (serine acetyl transferase) was also found. comparison of the conserved regions of the three protein sequences indicated a domain that may be an active site of the enzymes. | 1989 | 2615659 |
| a functional analysis of t-dna gene 6b: the fine tuning of cytokinin effects on shoot development. | the physiological function in planta of t-dna gene 6b was studied under various experimental conditions. for this purpose the coding region of gene 6b was cloned behind the 1'-promoter of the tr-dna to enhance expression of the gene product in transformed plant cells. expression of the recombinant gene in leaf discs of nicotiana tabacum altered the capacity for shoot formation of the discs, induced by exogenous (i.e. bap in the growth medium or agrobacterial trans-zeatin produced under control o ... | 1989 | 2615760 |
| common nodabc genes in nod locus 1 of azorhizobium caulinodans: nucleotide sequence and plant-inducible expression. | azorhizobium caulinodans strain ors571 induces nitrogen-fixing nodules on roots and stem-located root primordia of sesbania rostrata. two essential nod loci have been previously identified in the bacterial genome, one of which (nod locus 1) shows weak homology with the common nodc gene of rhizobium meliloti. here we present the nucleotide sequence of this region and show that it contains three contiguous open reading frames (orfa, orfb and orfc) that are related to the nodabc genes of rhizobium ... | 1989 | 2615763 |
| galactosyl residue in exopolysaccharide from rhizobium meliloti jj-1 exposed to manganese in furanoid. | exopolysaccharide (eps) elaborated by rhizobium meliloti jj-1 in a manganese supplemented medium was isolated. periodate oxidation, reduction with sodium borohydride, followed by hydrolysis and subsequent capillary gas liquid chromatography of the derived alditol acetates revealed that d-galactose in this complex biopolymer is in furanoid form. this observation was further confirmed by 13carbon nuclear magnetic resonance (13c nmr). | 1989 | 2619288 |
| molecular linkage of the nif/fix and nod gene regions in rhizobium leguminosarum biovar trifolii. | nucleotide sequence analysis of a 2.5kb region downstream of the nifa gene from rhizobium leguminosarum biovar trifolii has resulted in linkage, at the dna sequence level, of the nifen, nifhdk, fixabcx, nifa gene cluster with the nodef, nodd, nodabcij genes. four genes have been identified within this intervening region. immediately 3' to the nifa gene is the nifb gene and the nifb-linked ferredoxin-encoding fdxn gene. downstream of fdxn in r. leguminosarum bv. trifolii and in rhizobium meliloti ... | 1989 | 2622339 |
| quantitative comparison of the laboratory and field competitiveness of rhizobium leguminosarum biovar phaseoli. | rhizobium leguminosarum bv. phaseoli kim5s outcompeted strain ce3 in bean (phaseolus vulgaris l.) root nodulation when plants were grown at any of three field sites, each with a different soil type and indigenous population, or in the laboratory in a sterilized sand, a sterilized peat-vermiculite mixture, or a nonsterile field soil. a mathematical model describing nodulation competitiveness was empirically derived to evaluate the relative competitiveness of the two strains under these conditions ... | 1989 | 2624457 |
| immunological identification and distribution of dissimilatory heme cd1 and nonheme copper nitrite reductases in denitrifying bacteria. | polyclonal antibodies were used to identify heme or copper nitrite reductases in the following groups: 23 taxonomically diverse denitrifiers from culture collections, 100 numerically dominant denitrifiers from geographically diverse environments, and 51 denitrifiers from a culture collection not selected for denitrification. antisera were raised against heme nitrite reductases from pseudomonas aeruginosa and pseudomonas stutzeri and against copper nitrite reductase from achromobacter cycloclaste ... | 1989 | 2624465 |
| the structures of the lipopolysaccharide core components from rhizobium leguminosarum biovar phaseoli ce3 and two of its symbiotic mutants, ce109 and ce309. | the structures for the core regions of the lipopolysaccharides (lpss) from r. leguminosarum bv. phaseoli ce3 and two symbiotic mutants were determined by g.l.c.-m.s., proton nuclear magnetic resonance spectroscopy (n.m.r.), fast-atom-bombardment mass spectrometry (f.a.b.-m.s.), and by comparison with known structures from the lps of r. leguminosarum bv. trifolii anu843. the core oligosaccharides were separated into two components, p2-2 and p2-3, by gel-filtration chromatography using bio-gel p2. ... | 1989 | 2636039 |
| transfer and function of t-dna genes from agrobacterium ti and ri plasmids in plants. | | 1989 | 2643473 |
| rhizobium-legume nodulation: life together in the underground. | | 1989 | 2643474 |
| escherichia coli sigma 54 rna polymerase recognizes caulobacter crescentus flbg and flan flagellar gene promoters in vitro. | a set of the periodically regulated flagellar (fla) genes of caulobacter crescentus contain conserved promoter sequence elements at -24 and -12 that are very similar to the sequence of the nitrogen assimilation (ntr) and nitrogen fixation (nif) promoters of enteric bacteria and rhizobium spp. transcription from ntr and nif promoters requires rna polymerase containing sigma 54 instead of the usual sigma 70 and, in the case of the ntr promoters, is activated by the transcription factors nri and nr ... | 1989 | 2644197 |
| isolation of a rhizobium phaseoli cytochrome mutant with enhanced respiration and symbiotic nitrogen fixation. | cultured cells of a rhizobium phaseoli wild-type strain (ce2) possess b-type and c-type cytochromes and two terminal oxidases: cytochromes o and aa3. cytochrome aa3 was partially expressed when ce2 cells were grown on minimal medium, during symbiosis, and in well-aerated liquid cultures in a complex medium (py2). two cytochrome mutants of r. phaseoli were obtained and characterized. a tn5-mob-induced mutant, cfn4201, expressed diminished amounts of b-type and c-type cytochromes, showed an enhanc ... | 1989 | 2644201 |
| rhizobium leguminosarum cfn42 genetic regions encoding lipopolysaccharide structures essential for complete nodule development on bean plants. | eight symbiotic mutants defective in lipopolysaccharide (lps) synthesis were isolated from rhizobium leguminosarum biovar phaseoli cfn42. these eight strains elicited small white nodules lacking infected cells when inoculated onto bean plants. the mutants had undetectable or greatly diminished amounts of the complete lps (lps i), whereas amounts of an lps lacking the o antigen (lps ii) greatly increased. apparent lps bands that migrated between lps i and lps ii on sodium dodecyl sulfate-polyacry ... | 1989 | 2644215 |
| localization and symbiotic function of a region on the rhizobium leguminosarum sym plasmid prl1ji responsible for a secreted, flavonoid-inducible 50-kilodalton protein. | a previously described (r. a. de maagd, c. a. wijffelman, e. pees, and b. j. j. lugtenberg, j. bacteriol. 170:4424-4427, 1988) sym plasmid-dependent, naringenin-inducible 50-kilodalton protein of rhizobium leguminosarum biovar viciae is further characterized in this paper. the protein was overproduced by constructing a strain containing multiple copies of the r. meliloti nodd gene, which facilitated its purification. an antiserum was used to screen tn5 insertion mutants located in the prl1ji reg ... | 1989 | 2644226 |
| molecular cloning of a gene for indole-3-acetamide hydrolase from bradyrhizobium japonicum. | a plafr1 cosmid genomic library of wild-type bradyrhizobium japonicum j1063 was constructed. a cosmid clone designated pbjj4, containing a 26-kilobase (kb) dna insert, was identified as being able to confer the ability to convert alpha-naphthaleneacetamide acid on b. japonicum j1b7 rifr, which cannot perform this conversion. the gene coding for the enzyme that converts alpha-naphthaleneacetamide to alpha-naphthaleneacetic acid was localized in the 3.5-kb region of pbjj4 by recloning in plasmid p ... | 1989 | 2646294 |
| rhizobium meliloti regulatory gene fixj activates transcription of r. meliloti nifa and fixk genes in escherichia coli. | when present in escherichia coli on the multicopy expression vector puc19, a rhizobium meliloti regulatory gene, fixj, belonging to a two-component regulatory system, activated the expression of two r. meliloti symbiotic genes, nifa and fixk. primer extension by reverse transcription showed that fixj stimulates nifa expression in e. coli by activating pnifa. | 1989 | 2646295 |
| three distinct regulatory elements comprise the upstream promoter region of the nopaline synthase gene. | fine deletion mutants were generated in the upstream control region of the nopaline synthase (nos) promoter to define the position and role of upstream regulatory elements. the results indicated that the 8 bp sequence (cagaaacc) at -106/-113 and its inverted repeat (ggtttctg) at -140/-147 are important for promoter function. the downstream element appears more important than the upstream element since deletion of the former reduced promoter activity more significantly than deletion of the latter ... | 1989 | 2651882 |
| genetic manipulation of the chloroplast genome. | | 1989 | 2653479 |
| integration of multiple copies of a foreign sequence into the ti plasmid of agrobacterium tumefaciens. | a method for constructing ti plasmids bearing multiple copies of a sequence integrated in tandem is described. a small plasmid that confers tetracycline resistance (tcr), contains homology to a ti plasmid, and is unable to replicate in agrobacterium tumefaciens, was mobilized from escherichia coli to a. tumefaciens. ti plasmids of exconjugants selected for resistance to 12-14 micrograms tc/ml all contained multiple tandem repeats of the integrative plasmid. tc-sensitive variants with fewer integ ... | 1989 | 2653967 |
| estimation of nitrogenase activity in the presence of ethylene biosynthesis by use of deuterated acetylene as a substrate. | nitrogenase reduces deuterated acetylene primarily to cis dideuterated ethylene. this can be distinguished from undeuterated ethylene by the use of fourier transform infrared spectroscopy. characteristic bands in the region from 800 to 3,500 cm-1 can be used to identify and quantitate levels of these products. this technique is applicable to field studies of nitrogen fixation where ethylene biosynthesis by plants or bacteria is occurring. we have verified the reaction stoichiometry by using kleb ... | 1989 | 2655535 |
| rhizobium meliloti anthranilate synthase gene: cloning, sequence, and expression in escherichia coli. | we determined the dna sequence of the rhizobium meliloti gene encoding anthranilate synthase, the first enzyme of the tryptophan pathway. sequences similar to those seen for the two subunits of the enzyme as found in all other procaryotic species studied are present in a single open reading frame of 729 codons. this apparent gene fusion joins the c terminus of the large subunit (trpe) to the n terminus of the small subunit (trpg) through a short connecting segment. we designate the fused gene tr ... | 1989 | 2656657 |
| molecular aspects of the energetics of nitrogen fixation in rhizobium-legume symbioses. | | 1989 | 2659085 |
| cloning and sequencing of the gltx gene, encoding the glutamyl-trna synthetase of rhizobium meliloti a2. | the gltx gene, coding for the glutamyl-trna synthetase of rhizobium meliloti a2, was cloned by using as probe a synthetic oligonucleotide corresponding to the amino acid sequence of a segment of the glutamyl-trna synthetase. the codons chosen for this 42-mer were those most frequently used in a set of r. meliloti genes. dna sequence analysis revealed an open reading frame of 484 codons, encoding a polypeptide of mr 54,166 containing the amino acid sequences of an nh2-terminal and various interna ... | 1989 | 2661539 |
| the nucleotide sequence of a soybean mosaic virus coat protein-coding region and its expression in escherichia coli, agrobacterium tumefaciens and tobacco callus. | a dna complementary to the 3'-terminal 1168 nucleotides of the genome of the n strain of soybean mosaic virus (smv) has been cloned and sequenced. cdna sequence and coat protein analyses indicate that the smv coat protein-coding region is at the 3' end of the genome, and that the coat protein is processed from a larger protein. the coat protein-coding sequence is predicted to be 795 nucleotides in length, encoding a protein of 265 amino acids with a calculated mr of 29,857. the 3' untranslated r ... | 1989 | 2661723 |
| fixk, a gene homologous with fnr and crp from escherichia coli, regulates nitrogen fixation genes both positively and negatively in rhizobium meliloti. | nitrogen fixation genes are shown to undergo a complex positive and negative regulation in rhizobium meliloti. activation of fixn by fixlj is shown to require a third regulatory gene, fixk. as fixk is activated by fixlj, we propose a cascade model for fixn regulation such that fixlj activates fixn via fixk. in addition fixk negatively regulates expression of the nif-specific activator nifa as well as its own expression by autoregulation. thus nifa and fixk are subject to a mixed regulation, posi ... | 1989 | 2663474 |
| virg of agrobacterium tumefaciens plasmid ptic58 encodes a dna-binding protein. | virulence genes of the agrobacterium tumefaciens ti plasmid are positively regulated by the products of vira and virg. to study the dna-binding properties of the virg protein, a translational fusion between virg and the trpe gene of escherichia coli was constructed, and antiserum was raised against the encoded fusion protein. using this antiserum, a protein of mr congruent to 29,000, a size similar to that calculated from the virg nucleotide sequence, was detected in an e. coli strain harbouring ... | 1989 | 2664419 |
| construction of chimaeric promoter regions by exchange of the upstream regulatory sequences from fdhf and nif genes. | hybrid 5' regulatory regions were constructed in which the upstream activator sequence (uas) and promoter of various nif genes were exchanged with the upstream regulatory sequence (urs) of the fdhf gene from escherichia coli. they were analysed for their regulatory response under different growth conditions with the aid of fdhf'-'lacz or nif'-'lacz fusions. placement of the uas from the bradyrhizobium japonicum nifh gene in front of the spacer (dna region between urs and promoter) plus promoter ... | 1989 | 2664422 |
| gene transfer system for rhodopseudomonas viridis. | a gene transfer system for rhodopseudomonas viridis was established which uses conjugation with escherichia coli s17-i as the donor and mobilizable plasmids as vectors. initially, plasmids of the incompatibility group p1 (prk290 and prk404) were used. the more effective shuttle vectors between e. coli and r. viridis, pkv1 and pkvs1, were derived from plasmid pbr322 and showed the highest conjugation frequency (10(-2] thus far demonstrated in purple bacteria. it was also demonstrated that rhizobi ... | 1989 | 2666398 |
| influence of soil variables on in situ plasmid transfer from escherichia coli to rhizobium fredii. | a model system was established to determine whether intergeneric plasmid transfer occurs in soil and how various soil variables affect the rate of plasmid transfer. the donor bacterium, escherichia coli hb101 carrying plasmid pblk1-2 (prk2073::tn5), and the recipient bacterium, rhizobium fredii usda 201, were inoculated into a sterile adelphia fine-sandy-loam soil. transconjugants were enumerated by direct plating on antibiotic-amended hm [n-2-hydroxyethylpiperazine-n'-2-ethanesulfonic acid; 2-( ... | 1989 | 2669634 |
| putative start codon ttg for the regulatory protein virg of the hairy-root-inducing plasmid pria4. | the nucleotide sequence of the virg gene for a transcriptional activator on the agropine-type hairy-root-inducing plasmid pria4 was determined. the sequence contained one possible open reading frame. the gene product with a molecular size of 26.5 kda was identified by an escherichia coli coupled-transcription-translation system using cloned virg plasmids as templates. however, neither an atg nor a gtg start codon which could give rise to such a protein was identified in the nucleotide sequence. ... | 1989 | 2670679 |
| subcellular localization of the nodd gene product in rhizobium leguminosarum. | in rhizobium strains the transcription of symbiosis plasmid-localized nod genes, except nodd, is induced by plant flavonoids and requires the nodd gene product. in order to localize nodd protein in r. leguminosarum, a nodd protein-specific antiserum was raised against a lacz'-'nodd gene fusion product. using these antibodies, we determined that the nodd protein is located exclusively in the cytoplasmic membrane of wild-type r. leguminosarum biovar viciae cells. this localization is independent o ... | 1989 | 2670892 |
| ars region tl-dna on octopine type ti plasmids. | in the tl-dna region of the octopine type ti plasmids, an ars region was assigned as the dna segment conferring the replicational ability to yip5 in saccharomyces cerevisiae. t-dna: yip5 hybrid plasmids containing a particular t-dna region could transform yeast cells at a frequency of 10(3)-10(4) transformants per microgram plasmid dna and they were rescued in escherichia coli, although the transformed phenotype was mitotically unstable. the instability was inferred to be caused by segregation o ... | 1989 | 2674656 |
| efficient transformation of agrobacterium spp. by electroporation. | | 1989 | 2674902 |
| a nod at differentiation: the nodd gene product and initiation of rhizobium nodulation. | | 1989 | 2675422 |
| construction of an agrobacterium tumefaciens c58 reca mutant. | clones encoding the reca gene of agrobacterium tumefaciens c58 were isolated from a cosmid bank by complementation of an escherichia coli reca mutation. subcloning and mutagenesis with the lacz fusion transposon tn3hoho1 located the agrobacterium reca gene to a 1.3-kilobase segment of dna. beta-galactosidase expression from the fusions established the direction in which the gene was transcribed. the gene restored homologous recombination as well as dna repair functions in e. coli reca mutants. s ... | 1989 | 2676971 |
| firefly luciferase as a reporter enzyme for measuring gene expression in vegetative and symbiotic rhizobium meliloti and other gram-negative bacteria. | a dna segment carrying a cdna copy of the luciferase gene (luc) of the north american firefly photinus pyralis, fused to the lambda pr promoter and expressed in escherichia coli [de wet et al., proc. natl. acad. sci. usa 82 (1985) 7870-7873], was inserted into a broad-host-range plasmid vector and established in a variety of gram-negative bacteria. luciferase activity, expressed from the lambda pr promoter, was detected in both intact cells and extracts prepared from cells of strains of rhizobiu ... | 1989 | 2680767 |
| [the study of binding of the virg gene product with the vird gene promotor region of the agrobacterium tumefaciens ti-plasmid c58]. | the 1.5 kb ecori--hindiii fragment of the ptic58 containing the vird regulatory sequence demonstrates a constitutive promoter activity in e. coli background and an inducible one in agrobacterium. the virg gene was cloned in ptz19r plasmid. to reveal the virg product--vird regulatory sequence interaction a few protein fractions of e. coli harbouring the obtained recombinant plasmid ptz19g lysate were used. page-retardation assay revealed the specific binding between the 1.5 kb dna fragment contai ... | 1989 | 2682221 |