Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| organ-dependent regulation of a plant promoter isolated from rice by 'promoter-trapping' in tobacco. | a vector containing a transcriptionally inactive neomycin phosphotransferase ii gene was used to select promoter sequences from a pool of random genomic dna fragments. this paper describes how one such sequence (p4.7) isolated from oryza sativa acts as a hormonally regulated promoter in nicotiana tabacum. relative expression ratios in leaf, root, midrib, callus, and stem tissue of tobacco plants are 1:5:4:10:17. histochemical assays show that p4.7 activates the uida reporter gene throughout the ... | 1991 | 1844878 |
| aerobic inactivation of rhizobium meliloti nifa in escherichia coli is mediated by lon and two newly identified genes, snob and snoc. | the rhizobium meliloti nifa protein is an oxygen-sensitive transcriptional regulator of nitrogen fixation genes. regulation of nifa activity by oxygen occurs at the transcriptional level through fixlj and at the posttranslational level through the sensitivity of nifa to oxygen. we have previously reported that the nifa protein is sensitive to oxygen in escherichia coli as well as in r. meliloti. to investigate whether the posttranslational regulation of nifa is dependent on host factors conserve ... | 1991 | 1846139 |
| regulation of rhizobium meliloti exo genes in free-living cells and in planta examined by using tnphoa fusions. | the exo loci of rhizobium meliloti are necessary for the production of an acidic exopolysaccharide, eps i, that is needed for alfalfa nodule invasion by strain rm1021. we have isolated and characterized alkaline phosphatase fusions made with tnphoa in several exo loci of r. meliloti and used these fusions to examine the subcellular localization of exo gene products and the regulation of exo genes in free-living cells and in planta. in the course of this work, we isolated a new exo locus, exot. w ... | 1991 | 1846141 |
| the genomes of the family rhizobiaceae: size, stability, and rarely cutting restriction endonucleases. | the lack of high-resolution genetic or physical maps for the family rhizobiaceae limits our understanding of this agronomically important bacterial family. on the basis of statistical analyses of dna sequences of the rhizobiaceae and direct evaluation by pulsed-field agarose gel electrophoresis (pfe), five restriction endonucleases with at-rich target sites were identified as the most rarely cutting: asei (5'-attaat-3'), drai (5'-tttaaa-3'), spei (5'-actagt-3'), sspi (5'-aataat-3'), and xbai (5' ... | 1991 | 1846148 |
| characterization of three agrobacterium tumefaciens avirulent mutants with chromosomal mutations that affect induction of vir genes. | three agrobacterium tumefaciens mutants with chromosomal mutations that affect bacterial virulence were isolated by transposon mutagenesis. two of the mutants were avirulent on all hosts tested. the third mutant, ivr-211, was a host range mutant which was avirulent on bryophyllum diagremontiana, nicotiana tabacum, n. debneyi, n. glauca, and daucus carota but was virulent on zinnia elegans and lycopersicon esculentum (tomato). that the mutant phenotype was due to the transposon insertion was dete ... | 1991 | 1846853 |
| aerobic growth and respiration of a delta-aminolevulinic acid synthase (hema) mutant of bradyrhizobium japonicum. | oxygen-dependent growth of the bradyrhizobium japonicum hema mutant mlg1 (m.l. guerinot and b.k. chelm, proc. natl. acad. sci. usa 83:1837-1841, 1986) was demonstrated in cultured cells in the absence of exogenous delta-aminolevulinic acid (ala), but growth of analogous mutants of rhizobium meliloti or of escherichia coli was not observed unless ala was added to the yeast extract-containing media. no heme could be detected in extracts of strain mlg1 cells as measured by the absorption or by the ... | 1991 | 1846857 |
| isolation and characterization of insertion sequence elements from gram-negative bacteria by using new broad-host-range, positive selection vectors. | on the basis of an rsf1010-derived broad-host-range vector, three different systems which enable positive detection and isolation of insertion sequence (is) elements from gram-negative bacteria were constructed. vectors psup104-phes, psup104-rpsl, and psup104-sac were used successfully in a number of rhizobium strains and in xanthomonas campestris. more than 20 different is elements were isolated and characterized. the 16 is elements from rhizobium meliloti were further used to characterize vari ... | 1991 | 1847366 |
| purification and properties of malonyl-coa synthetase from rhizobium japonicum. | a novel malonyl-coa synthetase was found in rhizobium japonicum bacteroid of the soybean nodule. the levels of the enzyme in the free-living cells grown on a variety of carbon sources including glucose were similar, indicating that this enzyme is not inducible. the malonyl-coa synthetase from glucose-grown rhizobium japonicum was purified to homogeneity. the mr of the enzyme was determined to be 58,000 by gel filtration on a sephacryl s-300 and by sds/page respectively, indicating a single polyp ... | 1991 | 1847615 |
| identification of an osmotically induced periplasmic glycine betaine-binding protein from rhizobium meliloti. | the effect of salt stress on glycine betaine-binding activity has been investigated in periplasmic fractions released from rhizobium meliloti 102f34 by cold osmotic shock. binding activity was monitored by three techniques: equilibrium dialysis, filter procedure, and detection of 14c ligand-protein binding by direct non-denaturing polyacrylamide gel electrophoresis (page) followed by autoradiography. the three methods demonstrated the existence of a strong glycine betaine-binding activity, but o ... | 1991 | 1847827 |
| a haemoprotein with kinase activity encoded by the oxygen sensor of rhizobium meliloti. | the expression of the nitrogen-fixation genes of rhizobium meliloti is controlled by oxygen. these genes are induced when the free oxygen concentration is reduced to microaerobic levels. two regulator proteins, fixl and fixj, initiate the oxygen-response cascade, and the genes that encode them have been cloned. the fixl product seems to be a transmembrane sensor that modulates the activity of the fixj product, a cytoplasmic regulator. fixl and fixj are homologous to a family of bacterial two-com ... | 1991 | 1848683 |
| the hexose transporters at the plasma membrane and the tonoplast of transformed plant cells: kinetic characterization of two distinct carriers. | the plasma membrane hexose transporter and the tonoplast hexose transporter from heterotrophically grown transformed nicotiana tabacum cells have been studied in vitro using membrane vesicles for trans-zero transport studies. in highly purified phase-partitioned outside-out plasma membrane vesicles (pmv) the hexose transporter showed an apparent km value of 230 microm (substrate: 3-o-methyl-d-glucose (3-omg); phi 7.2/pho 7.2), which was reduced to 120 microm when a ph gradient was imposed (pho 5 ... | 1991 | 1849009 |
| identification and nucleotide sequence of rhizobium meliloti insertion sequence isrm3: similarity between the putative transposase encoded by isrm3 and those encoded by staphylococcus aureus is256 and thiobacillus ferrooxidans ist2. | the insertion sequence isrm3 was discovered simultaneously in different rhizobium meliloti strains by probing southern blots of total cellular dna with 32p-labeled pta2. this plasmid is indigenous to strain iz450 and fortuitously contained four copies of isrm3. by using an internal ecori fragment as a specific probe (prwrm31), homology to isrm3 was subsequently detected in over 90% of r. meliloti strains tested from different geographical locations around the world. the frequency of stable nonle ... | 1991 | 1849509 |
| analysis of a 1600-kilobase rhizobium meliloti megaplasmid using defined deletions generated in vivo. | a series of 120-600 kilobase deletions with defined endpoints were made in the 1600-kilobase rhizobium meliloti megaplasmid prmesu47b, by homologous recombination between the is50 elements of transposon insertions. utilizing is 50-mediated homologous recombination we also made defined reductions in deletion size and combined adjacent deletions. deletion structure was confirmed by phage transduction and southern hybridization analysis. collectively these deletions span 1400 kilobases of prmesu47b ... | 1991 | 1849856 |
| direct evidence of the entner-doudoroff pathway operating in the metabolism of d-glucosamine in bacteria. | pseudomonas fluorescens (migula) (ifo 14808) has both a membrane-bound pqq-dependent d-glucose (d-glc) dehydrogenase [ec 1.1.99.17] [which also acts on d-glucosamine (d-glcn)] and a plp-dependent d-glucosaminate (d-glcna) dehydratase [ec 4.2.1.26]. further, these two enzymes were induced when d-glcn was added to the culture medium. however, d-glucosamine-6-phosphate (d-glcn-6-p) isomerase [ec 5.3.1.10], another enzyme involved in the metabolism of d-glcn, was only present at a low level in this ... | 1991 | 1849886 |
| nucleotide sequence of the fixabc region of azorhizobium caulinodans ors571: similarity of the fixb product with eukaryotic flavoproteins, characterization of fixx, and identification of nifw. | the nucleotide sequence of a 4.1 kb dna fragment containing the fixabc region of azorhizobium caulinodans was established. the three gene products were very similar to the corresponding polypeptides of rhizobium meliloti. the c-terminal domains of both fixb products displayed a high degree of similarity with the alpha-subunits of rat and human electron transfer flavoproteins, suggesting a role for the fixb protein in a redox reaction. two open reading frames (orf) were found downstream of fixc. ... | 1991 | 1850088 |
| genetic analysis of a region of the rhizobium meliloti psym plasmid specifying catabolism of trigonelline, a secondary metabolite present in legumes. | genes controlling the catabolism of trigonelline, a secondary metabolite that is often present in legumes, are located on the psym megaplasmid of rhizobium meliloti. to investigate the role of bacterial trigonelline catabolism in the rhizobium-legume symbiosis, we identified and characterized the r. meliloti rcr2011 genetic loci (trc) controlling trigonelline catabolism. tn5-b20 mutagenesis showed that the trc region is a continuous dna segment of 9 kb located 4 kb downstream of the nifab and fd ... | 1991 | 1850402 |
| analysis of rhizobium meliloti nodulation mutant wl131: novel insertion sequence isrm3 in nodg and altered nodh protein product. | nodulation (nod) genes are required for invasion of legumes by rhizobium bacteria. mutant wl131 is a derivative of 102f51 that has a severe nod- phenotype on alfalfa. upon examination of the extended dna region containing host-specific nodulation genes nodfeg and nodh, we found that the nodg gene of wl131 bears a novel insertion sequence, isrm3. complementation studies implied, however, that the phenotype on alfalfa correlated with the nodh locus. we found that nodh in wl131 encodes an altered g ... | 1991 | 1850728 |
| homology of the ligand-binding regions of rhizobium symbiotic regulatory protein nodd and vertebrate nuclear receptors. | the signal specificity and structure of sensor-activator proteins from different species (nodd of rhizobium bacteria and vertebrate nuclear receptors) were compared. several compounds (including flavonoids, coumestrol and estradiol) that bind to mammalian receptors also interact with nodd proteins. nodd-dependent synergism of the signal compounds luteolin and catechin was observed suggesting that these compounds bind directly to nodd. two regions comprising 63 and 37 amino acids in nodd showed 4 ... | 1991 | 1851955 |
| organization of the agropine synthesis region of the t-dna of the ri plasmid from agrobacterium rhizogenes. | the agropine/mannopine synthesis region of the tr region of the ri plasmid of agrobacterium rhizogenes strain a4 was localized on the basis of sequence similarity with probes from ti plasmids of agrobacterium tumefaciens and analysis of transposon insertions. the nucleotide sequence of the right part of the tr-dna of pria4, encompassing the three genes involved in mannityl-opine synthesis, was determined and compared to the sequence of the corresponding region of the octopine-type ti plasmid pti ... | 1991 | 1852015 |
| formation of rhizobium phaseoli symbiotic plasmids by genetic recombination. | we report here the formation of symbiotic plasmids (psyms), by genetic recombination between rearranged psyms, which lack symbiotic information, and resistance plasmids carrying parts of different symbiotic plasmids (r's). this recombination was found to occur both between plasmids derived from different rhizobium phaseoli isolates, and between plasmids derived from strains obtained from the same original isolate. we also present evidence on the formation of a functional symbiotic plasmid by rec ... | 1991 | 1857210 |
| modular structure of fixj: homology of the transcriptional activator domain with the -35 binding domain of sigma factors. | the fixl/fixj two-component system is a global regulator of nitrogen-fixation genes in rhizobium meliloti. the transcriptional activator fixj contains two modules: its n-terminal module is homologous with other two-component regulators; its c-terminal module shows homology with various transcriptional activators, and with the c-terminal region of sigma factors, which is involved in the discrimination of the -35 region of bacterial promoters. we show that the c-terminal module of fixj contains th ... | 1991 | 1857213 |
| inoculation of vicia sativa subsp. nigra roots with rhizobium leguminosarum biovar viciae results in release of nod gene activating flavanones and chalcones. | flavonoids released by roots of vicia sativa subsp. nigra (v. sativa) activate nodulation genes of the homologous bacterium rhizobium leguminosarum biovar viciae (r. l. viciae). inoculation of v. sativa roots with infective r. l. viciae bacteria largely increases the nod gene-inducing ability of v. sativa root exudate (a.a.n. van brussel et al., j bact 172: 5394-5401). the present study showed that, in contrast to sterile roots and roots inoculated with r. l. viciae cured of its sym plasmid, roo ... | 1991 | 1859867 |
| 35s-beta-glucuronidase gene blocks biological effects of cotransferred iaa genes. | the iaam and iaah genes of agrobacterium tumefaciens and agrobacterium rhizogenes play an important role in crown gall and hairy root disease. the iaam gene codes for tryptophan monooxygenase which converts tryptophan into indole-3-acetamide (iam). iam is converted into the auxin indole-3-acetic acid (iaa) by indoleacetamide hydrolase, encoded by the iaah gene. in functional studies on the activity of the iaa genes of the tb region of the a. tumefaciens biotype iii strain tm4, the frequently use ... | 1991 | 1859868 |
| electroporation of megaplasmids into agrobacterium. | 1991 | 1859872 | |
| genetic and molecular analyses of pica, a plant-inducible locus on the agrobacterium tumefaciens chromosome. | pica is an agrobacterium tumefaciens chromosomal locus, identified by mu d11681 mutagenesis, that is inducible by certain acidic polysaccharides found in carrot root extract. cloning and genetic analysis of a pica::lacz fusion defined a region of the pica promoter that is responsible for the induction of this locus. furthermore, we identified a possible negative regulator of pica expression upstream of the pica locus. this sequence, denoted pgl, has extensive homology to polygalacturonase genes ... | 1991 | 1860822 |
| electrophoretic separation of the three rhizobium meliloti replicons. | the megaplasmids and the chromosome from the bacterium rhizobium meliloti 1021 were separated in preparative quantities by using transverse alternating-field gel electrophoresis. the genetic content of each electrophoretically separated band was determined by southern hybridization with replicon-specific probes and by comparison with agrobacterium tumefaciens transconjugants harboring either psym-a or psym-b megaplasmids. pulsed-field gel electrophoresis analyses of paci (5'-ttaattaa-3') and swa ... | 1991 | 1860826 |
| environmental conditions differentially affect vir gene induction in different agrobacterium strains. role of the vira sensor protein. | the induction of vir gene expression in different types of agrobacterium strains shows different ph sensitivity profiles. the ph sensitivity pattern demonstrated by octopine ti strains was similar to that of a supervirulent leucinopine ti strain, whereas this was different from that shown by nopaline ti strains and agropine ri strains. data are given which indicate that these differences are due to different properties of the vira genes of these wild types. an exceptional case was formed by stra ... | 1991 | 1863759 |
| isolation and characterization of rhizobium meliloti mutants affected in exopolysaccharide production. | rhizobium meliloti mutants affected in the production of exopolysaccharide (eps) were isolated after n-methyl-n'-nitro-n-nitrosoguanidine mutagenesis. the mutants were classified into three phenotypic classes: (i) exo-, rough mutants lacking exopolysaccharide; (ii) exos (for "small") which form tiny, compact colonies and synthesize reduced amounts of eps; and (iii) exoc (for "constitutive"), hypermucoid mutants which overproduce eps. hypermucoid strains showed increased resistance to desiccation ... | 1991 | 1867774 |
| nodt, a positively-acting cultivar specificity determinant controlling nodulation of trifolium subterraneum by rhizobium leguminosarum biovar trifolii. | rhizobium leguminosarum biovar trifolii strain ta1 nodulates a range of trifolium plants including red, white and subterranean clovers. nitrogen-fixing nodules are promptly initiated on the tap roots of these plants at the site of inoculation. in contrast to these associations, strain ta1 has a 'nod-' phenotype on a particular cultivar of subterranean clover called woogenellup (a.h. gibson, aust j agric sci 19: (1968) 907-918) where it induces rare, poorly developed, slow-to-appear and ineffecti ... | 1991 | 1868196 |
| sequence of the iaa and ipt region of different agrobacterium tumefaciens biotype iii octopine strains: reconstruction of octopine ti plasmid evolution. | the ta regions of biotype iii octopine/cucumopine (oc) ti plasmids are closely related to the tl region of the biotype i octopine ti plasmids ptiach5 and pti15955. sequence analysis shows that the limited and wide host range biotype iii oc ta regions are derived from a common ancestor structure which lacked the 6a gene found in the biotype i octopine tl region. the ta region of the wide host range oc ti plasmids has conserved most of the original tl-like structure. in most wide host range oc iso ... | 1991 | 1868199 |
| sequence of agrobacterium tumefaciens biotype iii auxin genes. | 1991 | 1868204 | |
| a quick method to estimate the t-dna copy number in transgenic plants at an early stage after transformation, using inverse pcr. | agrobacterium-mediated transformation of plants is known to result in transgenic plants with a variable number of integrated t-dna copies. our aim was to obtain transgenic tobacco plants containing one integrated t-dna copy per genome. therefore, a quick method was developed to estimate the t-dna copy number of young transgenic plantlets within 10 weeks after transformation. inverse polymerase chain reaction (ipcr) was used to amplify junction fragments, i.e. plant genomic dna sequences flanking ... | 1991 | 1868218 |
| isolation of the spinach nitrite reductase gene promoter which confers nitrate inducibility on gus gene expression in transgenic tobacco. | nitrite reductase is the second enzyme in the nitrate assimilatory pathway. the transcription of this gene is regulated by nitrate as well as a variety of other environmental and developmental factors. genomic clones containing the entire nitrite reductase gene have been isolated from a spinach genomic library and sequenced. the sequence is identical in the transcribed region to a previously isolated spinach nir cdna clone (back et al., 1988) except for the presence of three introns. the analysi ... | 1991 | 1868226 |
| production of beta-carotene in zymomonas mobilis and agrobacterium tumefaciens by introduction of the biosynthesis genes from erwinia uredovora. | the erwinia uredovora crtb, crte, crti, and crty genes required for beta-carotene biosynthesis were introduced by conjugal transfer into an ethanol-producing bacterium, zymomonas mobilis, and a phytopathogenic bacterium, agrobacterium tumefaciens, in which no carotenoid is synthesized. the transconjugants of z. mobilis and a. tumefaciens carrying these genes appeared as yellow colonies and produced 220 and 350 micrograms of beta-carotene per g of dry weight, respectively, in the stationary phase ... | 1991 | 1872613 |
| isolation of agrobacterium radiobacter from a central venous catheter. | a case of septicemia caused by agrobacterium radiobacter is reported in a patient undergoing chemotherapy treatment who had recently been neutropenic. agrobacterium radiobacter was isolated from the hickman line blood culture. the patient responded favorably to removal of the hickman catheter and treatment with amikacin and piperacillin. the molecular and biochemical characteristics of the isolate are presented. | 1991 | 1874251 |
| structural analysis of a second acidic exopolysaccharide of rhizobium meliloti that can function in alfalfa root nodule invasion. | 1991 | 1878885 | |
| agrobacterium radiobacter peritonitis in two patients maintained on chronic peritoneal dialysis. | we report two patients with end-stage renal disease maintained on chronic peritoneal dialysis who developed peritonitis in which the infecting organism was agrobacterium radiobacter, normally a rare pathogen in humans. both patients initially responded to antibiotics, but later relapsed and required catheter removal. neither had been exposed to soil or plant material. a radiobacter is yet another of a growing list of unusual organisms that infect the peritoneal cavity of peritoneal dialysis pati ... | 1991 | 1882836 |
| synchronous expression of leghaemoglobin genes in medicago truncatula during nitrogen-fixing root nodule development and response to exogenously supplied nitrate. | two leghaemoglobin genes from the diploid, autogamous medicago truncatula (mtlb1 and mtlb2) have been cloned and their nucleotide sequences determined. the deduced amino acid sequences encoded by these two genes differ significantly (18%), confirming that they belong to different sub-groups of medicago leghaemoglobin genes. rnase protection experiments have been used to show that both genes are transcriptionally active, and are expressed specifically in the nitrogen-fixing root nodule of m. trun ... | 1991 | 1883994 |
| cytosolic localization in transgenic plants of the rolc peptide from agrobacterium rhizogenes. | the rolc gene of agrobacterium rhizogenes codes for a peptide with an apparent molecular weight of approximately 20 kda. immunolocalization of the rolc peptide, in leaves of transgenic plants which are genetic mosaics for the expression of the rolc gene, is restricted to the phenotypically altered sectors. subcellular fractionation of homogenates from 35s-rolc transgenic leaves shows the cytosolic localization of the rolc peptide. | 1991 | 1884008 |
| rhizobium lipopolysaccharide modulates infection thread development in white clover root hairs. | the interaction between rhizobium lipopolysaccharide (lps) and white clover roots was examined. the limulus lysate assay indicated that rhizobium leguminosarum bv. trifolii (hereafter called r. trifolii) released lps into the external root environment of slide cultures. immunofluorescence and immunoelectron microscopy showed that purified lps from r. trifolii 0403 bound rapidly to root hair tips and infiltrated across the root hair wall. infection thread formation in root hairs was promoted by p ... | 1991 | 1885517 |
| regulation of phenolic catabolism in rhizobium leguminosarum biovar trifolii. | in members of the family rhizobiaceae, many phenolic compounds are degraded by the protocatechuate branch of the beta-ketoadipate pathway. in this paper we describe a novel pattern of induction of protocatechuate (pca) genes in rhizobium leguminosarum biovar trifolii. isolation of pca mutant strains revealed that 4-hydroxybenzoate, quinate, and 4-coumarate are degraded via the protocatechuate pathway. at least three inducers govern catabolism of 4-hydroxybenzoate to succinyl coenzyme a and acety ... | 1991 | 1885531 |
| stimulation of agrobacterium tumefaciens t-dna transfer by overdrive depends on a flanking sequence but not on helical position with respect to the border repeat. | t-dna transfer by agrobacterium tumefaciens depends on the right border repeat of the t-dna and is greatly stimulated by overdrive, an adjacent sequence. we report that the function of overdrive does not depend on helical position with respect to the border repeat. a synthetic 24-bp overdrive and a 12-bp region containing a fully conserved 8-bp core overdrive sequence stimulated virulence equally, but full function required additional bases to the left of the 24-bp sequence. | 1991 | 1885533 |
| plant signal molecules activate the syrb gene, which is required for syringomycin production by pseudomonas syringae pv. syringae. | the syrb gene is required for syringomycin production by pseudomonas syringae pv. syringae and full virulence during plant pathogenesis. strain b3ar132 containing a syrb::lacz fusion was used to detect transcriptional activation of the syrb gene in syringomycin minimal medium by plant metabolites with signal activity. among 34 plant phenolic compounds tested, arbutin, phenyl-beta-d-glucopyranoside, and salicin were shown to be strong inducers of syrb, giving rise to approximately 1,200 u of beta ... | 1991 | 1885550 |
| mutations that affect activity of the rhizobium meliloti trpe(g) promoter in rhizobium meliloti and escherichia coli. | the cloned rhizobium meliloti trpe(g) gene is not expressed in escherichia coli. oligonucleotide-directed mutagenesis was used to introduce base substitution mutations in the promoter region of this gene. three separate mutations that increased homology of the putative -10 region of this promoter with the e. coli -10 promoter consensus sequence by 1 bp converted this promoter to an active promoter in e. coli. a deletion extending to position -43 from the 5' side had a minor effect on transcripti ... | 1991 | 1885552 |
| in vitro activity of the nitrogen fixation regulatory protein fixj from rhizobium meliloti. | cell extracts of an escherichia coli strain that overproduces the regulatory protein fixj from rhizobium meliloti promoted transcription of fixk, a known fixj-dependent gene, in a coupled transcription-translation assay. activation by fixj was dependent on the sigma 70 holoenzyme form of rna polymerase. | 1991 | 1885556 |
| n-acetylglutamic acid: an extracellular nod signal of rhizobium trifolii anu843 that induces root hair branching and nodule-like primordia in white clover roots. | an extracellular metabolite purified from rhizobium trifolii anu843 was established as n-acetylglutamic acid (glunac) by 1h nmr and fourier transform ir spectroscopy, gas chromatography/mass spectrometry of its methylated product, and organic synthesis. tlc analyses indicated that extracellular accumulation of glunac by r. trifolii anu843 grown in defined biii culture medium was dependent on induction of its bacterial nodulation (nod) genes and the positive regulatory gene nodd on its symbiotic ... | 1991 | 1885611 |
| light scattering as a tool for characterizing biopolymer solutions and gels. | 1991 | 1889644 | |
| nifa of rhizobium meliloti is degraded by the products of genes lon, snob and snoc in escherichia coli. | 1991 | 1889837 | |
| survival of agrobacterium radiobacter k84 on various carriers for crown gall control. | screening was performed on nine carriers to find an improved formulation for agrobacterium radiobacter k84 cells. the survival data showed that it is possible to preserve a. radiobacter cells on dry solid supports for a long time provided that the storage temperature is 4 degrees c and that the inoculation volume for 4 x 10(9) cfu g-1 is not less than 0.15 ml g of carrier-1. on the other hand, a substantial carrier water content was necessary for room temperature storage. many materials proved t ... | 1991 | 1892394 |
| new patterns of gene activity in plants detected using an agrobacterium vector. | a vector has been designed that contains a truncated camv (cauliflower mosaic virus) 35s promoter fused to a receptor gene encoding beta-glucuronidase (gus), placed adjacent to the left border sequence of an agrobacterium vector. in potato plants transformed with this vector, different patterns of transcription were detected at high frequency using in situ assays for gus activity. previous studies in drosophila using analogous vectors have shown that the new patterns of transcription in many cas ... | 1991 | 1893100 |
| different promoter regions control level and tissue specificity of expression of agrobacterium rhizogenes rolb gene in plants. | expression of the rolb gene of a. rhizogenes t-dna triggers root differentiation in transformed plant cells. in order to study the regulation of this morphogenetic gene, the gus reporter gene was placed under the control of several deleted fragments of the rolb 5' non-coding region: carrot disc transformations and the analysis of transgenic tobacco plants containing these constructions identified the presence of distinct regulatory domains in the rolb promoter. two regions (located from position ... | 1991 | 1893111 |
| isolation of bradyrhizobium japonicum dna sequences that are transcribed at high levels in bacteroids. | dna sequences have been isolated that are expressed at high levels in bacteroids, the differentiated form of the soybean microsymbiont, bradyrhizobium japonicum. random-primed cdna was synthesized using total rna isolated from purified b. japonicum bacteroids or from cells grown in culture. when used directly to screen bacteriophage lambda libraries, these cdna probes produced a high background hybridization signal due to sequence similarity between b. japonicum and e. coli ribosomal dna (rdna) ... | 1991 | 1896009 |
| characterization of reca genes and reca mutants of rhizobium meliloti and rhizobium leguminosarum biovar viciae. | dna fragments carrying the reca genes of rhizobium meliloti and rhizobium leguminosarum biovar viciae were isolated by complementing a uv-sensitive reca- escherichia coli strain. sequence analysis revealed that the coding region of the r. meliloti reca gene consists of 1044 bp coding for 348 amino acids whereas the coding region of the r. leguminosarum bv. viciae reca gene has 1053 bp specifying 351 amino acids. the r. meliloti and r. leguminosarum bv. viciae reca genes show 84.8% homology at th ... | 1991 | 1896024 |
| structural genes of glutamate 1-semialdehyde aminotransferase for porphyrin synthesis in a cyanobacterium and escherichia coli. | in bacteria 5-aminolevulinate, the universal precursor in the biosynthesis of the porphyrin nucleus of hemes, chlorophylls and bilins is synthesised by two different pathways: in non-sulphur purple bacteria (rhodobacter) or rhizobium 5-aminolevulinate synthase condenses glycine and succinyl-coa into 5-aminolevulinate as is the case in mammalian cells and yeast. in cyanobacteria, green and purple sulphur bacteria, as in chloroplasts of higher plants and algae a three step pathway converts glutama ... | 1991 | 1900346 |
| effect of divalent metal cations on rhizobium meliloti beta-galactosidase. | 1991 | 1903737 | |
| transgene expression variability (position effect) of cat and gus reporter genes driven by linked divergent t-dna promoters. | forty-five individually transformed clonal tobacco callus lines were simultaneously assayed for both chloramphenicol acetyltransferase (cat) and beta-glucuronidase (gus) activity resulting from expression of introduced reporter genes driven by the adjacent and divergent mannopine (mas) promoters. excluding lines in which one or both of the enzyme activities was essentially zero, the activities of the reporter genes varied by as much as a factor of 136 (cat) and 175 (gus) between individual trans ... | 1991 | 1907871 |
| mutants of agrobacterium tumefaciens with elevated vir gene expression. | expression of agrobacterium tumefaciens virulence (vir) genes requires vira, virg, and a plant-derived inducing compound such as acetosyringone. to identify the critical functional domains of vira and virg, a mutational approach was used. agrobacterium a136 harboring plasmid pgp159, which contains vira, virg, and a reporter virb:lacz gene fusion, was mutagenized with uv light or nitrosoguanidine. survivors that formed blue colonies on a plate containing 5-bromo-4-chloro-3-indolyl beta-d-galactos ... | 1991 | 1908084 |
| agrobacterium rhizogenes pri8196 t-dna: mapping and dna sequence of functions involved in mannopine synthesis and hairy root differentiation. | this paper presents the map and dna sequence analysis of pri8196 transferred dna (t-dna) genes encoding root-inducing and mannopine synthesis functions. a canonical 24-base-pair border repeat as well as two "pseudoborders" are present at the functional right t-dna border. to the left of this border are homologs of the mas1' and mas2' genes of tr pria4. next to these are five open reading frames (orfs) homologous to orfs 10-14 of tl of pria4. orfs 10-12 (rola, rolb, and rolc) are less related to ... | 1991 | 1909028 |
| mechanism of phenolic activation of agrobacterium virulence genes: development of a specific inhibitor of bacterial sensor/response systems. | the aglycone of the dihydrodiconiferyl alcohol glycosides, a series of phenolic growth factors able to substitute for some of the hormone requirements of tobacco cell division, are also potent inducers of virulence gene expression in agrobacterium tumefaciens. however, these factors do not conform to the previously established structural requirements necessary for vir expression. systematic evaluation of the structural requirements of these inducers has led to a model detailing the role of the p ... | 1991 | 1909032 |
| six nodulation genes of nod box locus 4 in rhizobium meliloti are involved in nodulation signal production: nodm codes for d-glucosamine synthetase. | the nucleotide sequence of the nod box locus n4 in rhizobium meliloti was determined and revealed six genes organized in a single transcriptional unit, which are induced in response to a plant signal such as luteolin. mutations in these genes influence the early steps of nodule development on medicago, but have no detectable effect on melilotus, another host for r. meliloti. based on sequence homology, the first open reading frame (orf) corresponds to the nodm gene and the last to the nodn gene ... | 1991 | 1909418 |
| localization and orientation of the vird4 protein of agrobacterium tumefaciens in the cell membrane. | the vird4 gene of agrobacterium tumefaciens is essential for the formation of crown galls. analysis of the nucleotide sequence of vird4 has suggested that the n-terminal region of the encoded protein acts as a signal peptide for the transport of the vird4 protein to the cell membrane of agrobacterium. we have examined the localization and orientation of this protein in the cell membrane. when the nucleotides encoding the first 30 to 41 amino acids from the n-terminus of the vird4 protein were fu ... | 1991 | 1909421 |
| expression of a chimaeric granule-bound starch synthase-gus gene in transgenic potato plants. | granule-bound starch synthase is the key enzyme in amylose synthesis. the regulation of this gene was investigated using a chimaeric gene consisting of a 0.8 kb 5' upstream sequence of the granule-bound starch synthase gene from potato and the beta-glucuronidase gene which was introduced into potato using an agrobacterium tumefaciens binary vector system. the chimaeric gene was highly expressed in stolons and tubers, whereas the expression in leaves, stems or roots from greenhouse-grown plants w ... | 1991 | 1912493 |
| expression of a brassica napus extensin gene in the vascular system of transgenic tobacco and rape plants. | the organs and tissues where the brassica napus exta extensin gene is expressed have been identified. the exta gene with 3.75 kb of 5' flanking sequence was transferred to tobacco via disarmed agrobacterium tumefaciens vectors and transgenic plants regenerated. the gene was found to be inactive in transgenic tobacco leaf, but was active as measured by rna transcript assays in both stem and root tissues. to determine the cell-specific expression pattern of the exta gene, a promoter-reporter gene ... | 1991 | 1912494 |
| regulation of agrobacterium tumefaciens t-cyt gene expression in leaves of transgenic potato (solanum tuberosum l. cv. désirée) is strongly influenced by plant culture conditions. | the promoter region of the agrobacterium tumefaciens t-cyt gene was linked in a translational fusion to the coding dna of the reporter gene uida (for beta-glucuronidase or gus protein; ec 3.2.1.31) and to nos 3' flanking dna. the chimaeric gene was introduced by agrobacterium transformation into potato (solanum tuberosum l. cv. désirée). in nine transgenic lines, the average gus levels were highest in extracts from stems and roots of in vitro grown plants (ca. 11,000 gus activity units per pmol ... | 1991 | 1912495 |
| phenotypic changes in t-cyt-transformed potato plants are consistent with enhanced sensitivity of specific cell types to normal regulation by root-derived cytokinin. | from over forty independently isolated potato lines transformed with wild-type and promoter-mutated t-cyt genes, a number of lines were selected for examination of phenotypic changes in growth and development for plants grown in soil in a controlled environment. the three lines chosen for most detailed examination showed a wide spectrum of phenotypic changes. in comparisons with control potato cv. désirée, the plants of one line had a two- to three-fold increase in biomass production during earl ... | 1991 | 1912496 |
| phenotypically normal transgenic t-cyt tobacco plants as a model for the investigation of plant gene expression in response to phytohormonal stress. | the tumour-inducing t-dna gene 4 (t-cyt gene) of the nopaline ti plasmid ptic58 was cloned and introduced into tobacco cells by leaf disc transformation using agrobacterium plasmid vectors. tobacco shoots exposed to elevated cytokinin levels were unable to develop roots and lacked apical dominance. using exogenously applied phytohormone manipulations we were able to regenerate morphologically normal transgenic tobacco plants which differed in endogenous cytokinin levels from normal untransformed ... | 1991 | 1912501 |
| mismatch-specific dna breakdown in nuclear extract from tobacco (nicotiana tabacum) callus. | mismatch-specific enzymatic activity was sought for in nuclei from normal and transformed plant cells originating from tobacco (nicotiana tabacum) callus and crown gall tumor induced by agrobacterium tumefaciens. the specific enzymatic activity was assayed with substrates derived from synthetic oligonucleotides (19-mer sequences corresponding to the human k-ras gene). single-base changes in the middle of the sequence were the basis for creating heteroduplexes with all eight mismatches. homo- and ... | 1991 | 1912502 |
| the plant oncogene rolc is responsible for the release of cytokinins from glucoside conjugates. | the rolc gene of agrobacterium rhizogenes, which drastically affects growth and development of transgenic plants, codes for a cytokinin-beta-glucosidase. indeed, rolc protein expressed in escherichia coli as a fusion protein hydrolyses cytokinin glucosides, thus liberating free cytokinins. furthermore, beta-glucosidase activity present in e. coli extracts expressing the rolc protein was inhibited by affinity-purified antibodies specific for the rolc protein. finally, rolc proteins expressed in t ... | 1991 | 1915268 |
| the protein encoded by the rolb plant oncogene hydrolyses indole glucosides. | the rolb gene of agrobacterium rhizogenes, whose expression stimulates the formation of roots by transformed plant tissues and other growth alterations in transgenic plants, codes for a beta-glucosidase able to hydrolyse indole-beta-glucosides. indeed, we show that extracts of bacteria and/or plant tissue expressing the rolb protein hydrolyse indoxyl-beta-glucoside (plant indican). because of the structural similarity between indoxyl-beta-glucoside and indole-3-acetyl-beta-glucoside (iaa-beta-gl ... | 1991 | 1915286 |
| possible involvement of lys603 from escherichia coli glucosamine-6-phosphate synthase in the binding of its substrate fructose 6-phosphate. | pyridoxal 5'-phosphate is a competitive inhibitor of glucosamine-6-phosphate synthase with respect to the substrate fructose 6-phosphate. irreversible inactivation of pyridoxal-5'-phosphate-treated enzyme with [14c]-cyanide resulted in covalent incorporation of close to 1 mol pyridoxal 5'-phosphate/mol enzyme subunit. the enzyme-pyridoxal-5'-phosphate complex could also be inactivated by reduction with nabh3cn. sequence analysis of the unique radioactively labelled tryptic peptide, resulting fro ... | 1991 | 1915361 |
| agrobacterium rhizogenes lacz-rolc gene expression in escherichia coli: detection of the product in transgenic plants using rolc-specific antibodies. | the rolc sequence of the agrobacterium rhizogenes ri plasmid was fused in-frame to the 3' end of the lacz gene in plasmid pex3. the fusion protein rolc-beta-galactosidase was accumulated as insoluble inclusion bodies in escherichia coli. antibodies were raised in rabbits against the fusion protein. after affinity purification, rolc-specific antibodies were found to react with a 22-kda polypeptide prepared from roots of transgenic tobacco plants possessing a rolc gene. the result of differential ... | 1991 | 1916283 |
| the bacillus subtilis sigl gene encodes an equivalent of sigma 54 from gram-negative bacteria. | the levanase operon in bacillus subtilis is expressed from a -12, -24 promoter and transcription is stimulated by the regulator levr, which contains a domain homologous with the central domain of the nifa and ntrc family of regulators. we isolated mutants defective in the expression of the levanase operon. these strains contain mutations that define a gene, called sigl, located between cysb and sacb on the genetic map. the sigl gene was cloned and sequenced. it encodes a polypeptide containing 4 ... | 1991 | 1924373 |
| sugar response element enhances wound response of potato proteinase inhibitor ii promoter in transgenic tobacco. | the promoter region of the potato proteinase inhibitor ii (pi-ii) gene was studied to identify cis-acting regulatory sequences involved in sugar response using transgenic tobacco plants. the 5' control region covering an 892 nucleotide sequence upstream from the cap site and a 32 nucleotide untranslated region of the pi-ii promoter was able to activate a reporter chloramphenicol acetyltransferase (cat) gene by wounding or by incubating in a sugar-free medium. this wound response was further enha ... | 1991 | 1932687 |
| the tr-dna region carrying the auxin synthesis genes of the agrobacterium rhizogenes agropine-type plasmid pria4: nucleotide sequence analysis and introduction into tobacco plants. | we have determined the nucleotide sequence of a 6-kilobase fragment of the agrobacterium rhizogenes plasmid pria4 tr-region that carries genes (aux1 and aux2) responsible for auxin biosynthesis in transformed plant cells. sequence analysis revealed two open reading frames corresponding to proteins of 749 amino acids for the aux1 gene and 466 amino acids for the aux2 gene. we observed significant similarity between the amino acid sequences deduced from the pria4 aux genes and those of the auxin b ... | 1991 | 1932811 |
| role of t-region borders in agrobacterium host range. | the limited host range ab3 strain of agrobacterium tumefaciens induces tumors by transferring two t-regions, ta and tb. ta is a deleted version of the well-known biotype i octopine tl-region that lacks the iaa and ipt genes, but carries an intact oncogene, gene 6b, and typical left and right border sequences. tb carries two iaa genes that together code for the synthesis of indoleacetic acid. gene 6b and the iaa gene act synergistically when transferred in a coinoculation experiment. the ta-regio ... | 1991 | 1932812 |
| molecular analysis of an essential gene upstream of rpon in rhizobium ngr234. | rhizobium sp. ngr234 is a broad-host range strain. the rpon gene of this organism encodes a sigma factor which is a primary co-regulator of endosymbiosis. we characterized the locus upstream of rpon, and identified a contiguous open reading frame, here termed orf1. dna sequence analysis of this orf showed that it encoded a polypeptide highly conserved with a corresponding orf of rhizobium meliloti. the gene product contained two atp/gtp binding pockets. codon usage in the orf and the nitrogenase ... | 1991 | 1936948 |
| induction of the second exopolysaccharide (epsb) in rhizobium meliloti su47 by low phosphate concentrations. | in previous work, rhizobium meliloti su47 produced its alternative exopolysaccharide (epsb [also called eps ii]) only in strains that were genetically altered to activate epsb synthesis. here we report that epsb synthesis is not entirely cryptic but occurred under conditions of limiting phosphate. this was shown in several different exo mutants that are blocked in the synthesis of the normal exopolysaccharide, succinoglycan. in addition, epsb biosynthetic gene expression was markedly increased b ... | 1991 | 1938929 |
| a semiquantitative bioassay for relative virulence of agrobacterium tumefaciens strains on bryophyllum daigremontiana. | an assay to determine the relative virulence of wild-type and mutant strains of agrobacterium tumefaciens on leaves of bryophyllum daigremontiana has been developed. this assay is reproducible, is easy to learn, is not time consuming, and requires little space. the relative virulence of cellulose-minus mutants of a. tumefaciens was investigated with this assay. some of these mutants were unaltered in virulence, while others showed a marked reduction in virulence. | 1991 | 1938971 |
| induction of the alka gene of escherichia coli in gram-negative bacteria. | a broad-host-range plasmid containing a fusion of the alka and lacz genes of escherichia coli was introduced into various aerobic and facultative gram-negative bacteria--33 species belonging to 19 genera--to study the induction of expression of the alka gene by alkylating agents. the bacteria included species of the families enterobacteriaceae, pseudomonadaceae, rhizobiaceae, vibrionaceae, neisseriaceae, rhodospirillaceae, and azotobacteraceae. results obtained show that all bacteria tested, exc ... | 1991 | 1938974 |
| mutagenic effects of aluminium. | 1991 | 1944395 | |
| a novel highly unsaturated fatty acid moiety of lipo-oligosaccharide signals determines host specificity of rhizobium. | in rhizobium leguminosarum biovar viciae, the nodabc and nodfel operons are involved in the production of lipo-oligosaccharide signals which mediate host specificity. the structure of these metabolites and those produced in nod mutants links the node and nodl genes to specific chemical features of the signal molecules. a node-determined, highly unsaturated fatty acid and a nodl-determined o-acetyl substituent are essential for the ability of the signals to induce nodule meristems on the host pla ... | 1991 | 1944592 |
| characterization of the polyadenylation signal from the t-dna-encoded octopine synthase gene. | we have characterized the polyadenylation signal from the octopine synthase (ocs) gene. this signal directs mrna 3' end formation at a number of distinct sites. a combination of deletion and linker-substitution analyses revealed that each of these sites is controlled by multiple upstream sequence elements. upstream sequences relatively far (greater than 80 nt) from the ocs poly[a] sites were found to be needed for functioning of these sites. upstream sequences nearer to poly [a] sites were also ... | 1991 | 1945833 |
| [multifactorial study of the combined effect of rifampicin and microbial peptidoglycan in experimental plague infection]. | the combined effect of rifampicin and a microbial peptidoglycan was studied in multifactorial experiments on noninbred mice with plague infection. the effect of rifampicin and the immunomodulator was shown to be synergistic. the results of the multifactorial experiments provided designing of polynomial statistic models of the second order characterizing the animal survival rate and mean life-span and plotting of nomograms or equal level lines useful in optimization of the combined therapy parame ... | 1991 | 1953166 |
| nifa-ntra regulatory system activates transcription of nfe, a gene locus involved in nodulation competitiveness of rhizobium meliloti. | we have previously demonstrated that the rhizobium meliloti large plasmid prmegr4b carries the gene locus nodule formation efficiency (nfe) which is responsible for nodulation efficiency and competitive ability of strain gr4 on alfalfa roots. in this study we report that expression of nfe-lacz fusions in escherichia coli is activated in the presence of the cloned nifa gene of r. meliloti. this activation was found to be oxygen sensitive and to require the e. coli ntra gene product. in contrast t ... | 1991 | 1953295 |
| nucleotide sequence analysis of is427 and its target sites in agrobacterium tumefaciens t37. | we have determined the nucleotide sequence of is427, an insertion sequence from agrobacterium tumefaciens t37, is427 is 1271 bp long, contains 16-bp imperfect terminal inverted repeats, and generates a 2-bp target sequence duplication. it is present at three sites in the ptit37 plasmid and is absent from the chromosome of a. tumefaciens t37. each of the is427 elements sequenced was near a site with sequence homology to integration host factor (ihf)-binding sites which suggested that ihf may be i ... | 1990 | 1963949 |
| isolation of dna insertion elements from rhizobium meliloti which are able to promote transcription of adjacent genes. | in order to select insertion sequences able to promote transcription of flanking genes (isp elements), three mobilizable rsf1010 derived vectors were constructed. using promoterless antibiotic resistance genes, isp elements ranging from 0.75 to 2.9 kb were isolated from escherichia coli and rhizobium meliloti. restriction and hybridization experiments revealed that identical isp elements could be isolated from different r. meliloti strains and that one of these is similar to an insertion sequenc ... | 1990 | 1963950 |
| aminoglycoside-3''-adenyltransferase confers resistance to spectinomycin and streptomycin in nicotiana tabacum. | the bacterial gene aada encodes the enzyme aminoglycoside-3"-adenyltransferase that confers resistance to spectinomycin and streptomycin in escherichia coli. chimeric genes have been constructed for expression in plants, and were introduced into nicotiana tabacum by agrobacterium binary transformation vectors. spectinomycin or streptomycin in selective concentrations prevent greening of n. tabacum calli. transgenic clones, however, formed green calli on selective media containing spectinomycin, ... | 1990 | 1966273 |
| improved binary vectors for agrobacterium-mediated plant transformation. | improved plant transformation vectors were constructed which utilize the prihri origin of replication for highly stable maintenance in agrobacterium tumefaciens, the cole1 origin of replication for high copy maintenance in escherichia coli, and a gentamycin resistance gene as a strong selectable marker for bacteria. concise t-dna elements were engineered with border sequences from the tl-dna of ptia6, the tn5 neomycin phosphotransferase gene (npt ii) expressed from either camv 35s or mannopine s ... | 1990 | 1966276 |
| frequent spontaneous deletions of ri t-dna in agrobacterium rhizogenes transformed potato roots and regenerated plants. | the presence of t-dna was examined by southern blot analysis in 16 regenerated shoot lines derived from 6 agrobacterium rhizogenes-transformed root clones of solanum tuberosum l. cv. bintje. tr-dna, present in regenerated shoot lines from 3 out of 6 root clones was correlated with the presence of opines. one root clone produced opines up to 2.5 years of subculture. however, plant regeneration from and prolonged subculturing of this root clone resulted in loss of opine synthesis, caused by deleti ... | 1990 | 1966386 |
| a sensitive and simple paper chromatographic procedure for detecting neomycin phosphotransferase ii (nptii) gene expression. | 1990 | 1966388 | |
| agrobacterium-mediated dna transfer in sugar pine. | dna transfer using agrobacterium tumefaciens has been demonstrated in sugar pine, pinus lambertiana dougl. shoots derived from cytokinin-treated cotyledons formed galls after inoculation with a. tumefaciens strains containing the plasmid ptibo542. a selectable marker, neomycin phosphotransferase ii, conferring resistance to kanamycin, was transferred into sugar pine using a binary armed vector system. callus proliferated from the galls grew without hormones and in some cases, kanamycin-resistant ... | 1990 | 1966486 |
| heat-inducible hygromycin resistance in transgenic tobacco. | we have constructed a chimaeric gene consisting of the promoter of the soybean heat shock (hs) gene gmhsp17, 6-l, the coding region of a hygromycin phosphotransferase (hpt) gene, and the termination sequence of the nopaline synthase (nos) gene. this gene fusion was introduced into tobacco by agrobacterium-mediated gene transfer. heat-inducible synthesis of mrna was shown by northern hybridization, and translation of this rna into a functional protein was indicated by plant growth on hygromycin-c ... | 1990 | 1966490 |
| localization and characterization of the region encoding catabolism of mannopinic acid from the octopine-type ti plasmid pti15955. | the region of the octopine-type tumor-inducing (ti) plasmid pti15955 encoding catabolism of mannopinic acid was localized to an 18-kilobase (kb) segment mapping between ti plasmid coordinates 70 and 88. a subclone containing only this region normally did not allow utilization of any other mannityl opine. however, spontaneous mutants of the plasmid were isolated that conferred catabolism of agropinic acid. while the mutants remained regulated for mannopinic acid utilization, induction by this opi ... | 1990 | 1966675 |
| cloning and characterization of rhizobium meliloti loci required for symbiotic root nodule invasion. | an immunological assay of root nodule polypeptides was used to analyze the nodules induced by 25 symbiotically defective rhizobium meliloti mutants. differences in polypeptide accumulation in these nodules were used to divide the mutants into three subsets. one subset, containing two mutant strains, was further analyzed. nodules induced by these mutant strains lack both infection threads and bacteria. the kinetics of nodule formation by these mutant strains, by an exob mutant, and by mixed mutan ... | 1990 | 1966709 |
| rhizobium meliloti adenylate cyclase is related to eucaryotic adenylate and guanylate cyclases. | a gene from rhizobium meliloti coding for an adenylate cyclase was sequenced, and the deduced protein sequence was compared with those of other known adenylate cyclases. no similarity could be detected with the procaryotic counterparts. however, striking similarity was found with the catalytic region of saccharomyces cerevisiae adenylate cyclase, the cytoplasmic domains of bovine adenylate cyclase, and two mammalian guanylate cyclases. the gene was fused to the enteric beta-galactosidase, and th ... | 1990 | 1970565 |
| cell-specific expression in transgenic plants reveals nonoverlapping roles for chloroplast and cytosolic glutamine synthetase. | chloroplast and cytosolic isoforms of glutamine synthetase (gs; ec 6.3.1.2) are encoded by separate nuclear genes in plants. here we report that the promoters for chloroplast gs2 and cytosolic gs3a of pisum sativum confer nonoverlapping, cell-specific expression patterns on the beta-glucuronidase (gus) reporter gene in transgenic tobacco. the promoter for chloroplast gs2 directs gus expression within photosynthetic cell types (e.g., palisade parenchymal cells of the leaf blade, chlorenchymal cel ... | 1990 | 1970638 |
| involvement of glutamate as a carbon source in nitrogen-fixing rhizobium meliloti. | 1990 | 1974215 | |
| a previously unrecognized glutamine synthetase expressed in klebsiella pneumoniae from the glnt locus of rhizobium leguminosarum. | using glnt dna of rhizobium meliloti as a hybridization probe we identified a r. leguminosarum biovar phaseoli (r. l. phaseoli) locus (glnt) expressing a glutamine synthetase activity in klebsiella pneumoniae. a 2.2 kb dna fragment from r. l. phaseoli was cloned to give plasmid pmw5a, which shows interspecific complementation of a k. pneumoniae glna mutant. the cloned sequence did not show cross-hybridization to glna or glnii, the genes coding for two glutamine synthetase isozymes of rhizobium s ... | 1990 | 1980142 |
| human infections with strains of agrobacterium. | 1990 | 1980510 | |
| expression of glutamine synthetase genes in roots and nodules of phaseolus vulgaris following changes in the ammonium supply and infection with various rhizobium mutants. | in this paper we have examined whether the four glutamine synthetase (gln) genes, expressed in roots and nodules of phaseolus vulgaris are substrate-inducible by ammonium. manipulation of the ammonium pool in roots, through addition and removal of exogenous ammonium, did not elicit any changes in the abundances of the four mrnas thus suggesting that the gln genes in roots of this legume are neither substrate-inducible by ammonium nor derepressed during nitrogen starvation. in nodules the effect ... | 1990 | 1983288 |