Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| c(4)-dicarboxylate transport mutants of rhizobium trifolii form ineffective nodules on trifolium repens. | mutants of rhizobium trifolii strain 7012 defective in c(4)-dicarboxylate transport were isolated by using a selective procedure based on ph indicator media. the mutant strains cr7098 and cr7099 failed to grow on or transport succinate, fumarate, or malate, but grew at wild-type rates on several other carbon sources. the c(4)-dicarboxylate transport system was inducible in strain 7012, but was expressed constitutively in four out of five succinate-positive revertants of strain cr7098. in the fif ... | 1981 | 16593058 |
| increase in internode length of phaseolus lunatus l. caused by inoculation with a nitrate reductase-deficient strain of rhizobium sp. | dramatic differences in the height of lima beans (phaseolus lunatus l.) treated with two different rhizobium strains were studied. lima beans were grown in perlite in the greenhouse or in a minus-n culture solution in the growth chamber. the plants were inoculated with either rhizobium sp. (lima bean) strain 127e15, which contains the constitutive nitrate reductase activity, or strain 127e14, which lacks that activity. for up to 3 weeks, no growth differences were observed in the plants inoculat ... | 1981 | 16661605 |
| host-symbiont interactions : v. the structure of acidic extracellular polysaccharides secreted by rhizobium leguminosarum and rhizobium trifolii. | the sequence of the glycosyl residues and the anomeric configurations of the glycosyl linkages of the acidic polysaccharides secreted by rhizobium leguminosarum 128c53, rhizobium leguminosarum 128c63, rhizobium trifolii na30, and rhizobium trifolii 0403 have been determined. all four polysaccharides were found to have the following glycosyl repeating-unit structure, where galactosyl is gal, glucosyl is glc, glucuronosyl is glca, and pyruvyl is pyr: [formula: see text] each of the glycosyl residu ... | 1981 | 16661681 |
| differences in endogenous levels of gibberellin-like substances in nodules of phaseolus lunatus l. plants inoculated with two rhizobium strains. | lima bean plants (phaseolus lunatus l.) inoculated with rhizobium sp. strain 127e14, which lacks constitutive nitrate reductase activity, were significantly taller after 4 weeks of age than plants inoculated with strain 127e15, which contains constitutive nitrate reductase activity. plants inoculated with either strain responded to application of 5 micrograms gibberellic acid per plant with rapid internode elongation; plants inoculated with strain 127e15 became less responsive to gibberellic aci ... | 1981 | 16661869 |
| nitrogen stress and apparent photosynthesis in symbiotically grown pisum sativum l. | pea plants (pisum sativum l. cv. alaska) were inoculated individually with one of 15 rhizobium leguminosarum strains and grown under uniform environmental conditions in the absence of combined n. differences in effectiveness of the rhizobium strains produced plants with differing rates of whole plant apparent n(2) fixation and total n content at the same morphological stage of development. plants were analyzed to determine interactions between n(2) fixation, n allocation, apparent photosynthesis ... | 1981 | 16661907 |
| utilization of aldehydes and alcohols by soybean bacteroids. | aldehydes, alcohols and acids were tested for their ability to support acetylene reduction and oxygen consumption by rhizobium japonicum bacteroids isolated from soybean nodules. several alcohols and aldehydes increased acetylene reduction and oxygen uptake. this is consistent with the concept that the plant nodule cytosol can metabolize carbohydrate via anaerobic fermentative pathways. | 1981 | 16661942 |
| transient susceptibility of root cells in four common legumes to nodulation by rhizobia. | root cells of four common legumes were found to remain susceptible to nodulation by rhizobia for only a short period of time. delayed inoculation experiments conducted with these legume hosts indicated that the initially susceptible region of the root became progressively less susceptible if inoculations were delayed by a few hours. profiles of the frequency of nodule formation relative to marks indicating the regions of root and root hair development at the time of inoculation indicated that no ... | 1981 | 16662065 |
| carbon and nitrogen limitations on soybean seedling development. | carbon and nitrogen limitations on symbiotically grown soybean seedlings (glycine max [l.] merr.) were assessed by providing 0.0, 1.0, or 8.0 millimolar nh(4)no(3) and 320 or 1,000 microliters co(2)/liter for 22 days after planting. maximum development of the rhizobium-soybean symbiosis, as determined by acetylene reduction, was measured in the presence of 1.0 millimolar nh(4)no(3) under both levels of co(2). raising nh(4)no(3) from 0.0 to 8.0 millimolar under 320 microliters co(2)/liter increas ... | 1981 | 16662075 |
| in vitro nitrogen fixation by two actinomycete strains isolated from casuarina nodules. | acetylene reduction activity was demonstrated in pure cultures of two actinomycete strains isolated from nodules of casuarina equisetifolia. this activity was comparable to that of free-living rhizobium strains, but appeared to be less sensitive to po(2) and more sensitive to the presence of combined nitrogen. | 1981 | 16345698 |
| nodulation of acacia species by fast- and slow-growing tropical strains of rhizobium. | thirteen acacia species were classified into three groups according to effective nodulation response patterns with fast- and slow-growing tropical strains of rhizobium. the first group nodulated effectively with slow-growing, cowpea-type rhizobium strains; the second, with fast-growing rhizobium strains; and the third, with both fast- and slow-growing rhizobium strains. the rhizobium requirements of the acacia species of the second group were similar to those of leucaena leucocephala. | 1981 | 16345705 |
| fungicide enhancement of nitrogen fixation and colonization of phaseolus vulgaris by rhizobium phaseoli. | the number and weight of pods and the weight and nitrogen content of the tops of beans (phaseolus vulgaris) derived from seeds inoculated with a thiram-resistant strain of rhizobium phaseoli were increased if the seeds were treated with thiram before sowing in soil. a greater percentage of the nodules on 21-day-old plants were derived from the resistant strain, more nodules were formed, and these nodules were more effective in the presence of the fungicide than in its absence. these differences ... | 1981 | 16345715 |
| physiological characteristics of cowpea rhizobia: evaluation of symbiotic efficiency in vigna unguiculata. | one fast-growing and three slow-growing strains of rhizobium (isolated from cowpeas) were evaluated for symbiotic performance on vigna unguiculata (l.) walp. cultivar california no. 5 blackeyes. plants inoculated with slow-growing strains 176a22, 176a30, and 176a32 developed a maximum acetylene reduction activity of 24.6, 27.0, and 32 mumol of ethylene formed per plant per h, respectively, versus 6.4 mumol per plant per h in plants inoculated with the fast-growing strain 176a28. when inoculated ... | 1981 | 16345732 |
| effect of steam sterilization and gamma irradiation of peat on quality of rhizobium inoculants. | data obtained by independent tests on each of 483 batches of rhizobium inoculants for glycine max, medicago sativa, and arachis hypogaea, manufactured commercially in south africa, are reported and discussed. whereas the average cell count per gram per batch was well in excess of 10, inoculants for g. max and m. sativa manufactured with peat treated with gamma irradiation at a dose of 50 kgr contained significantly higher numbers of rhizobium cells than inoculants from peat which received 25 kgr ... | 1981 | 16345788 |
| release of rhizobium spp. from tropical soils and recovery for immunofluorescence enumeration. | limitations associated with immunofluorescence enumeration of bacteria in soil derive largely from the efficiency with which cells can be separated from soil particles and collected on membrane filters for staining. many tropical soils fix added bacteria tightly, resulting in low recoveries. eight soils, representative of three of the major soil orders found in the tropics (oxisols, vertisols, and inceptisols), were tested for recovery of added rhizobium strains. all except one hawaiian andept ( ... | 1981 | 16345824 |
| growth of rhizobium japonicum strains at temperatures above 27 degrees c. | a study was conducted to examine the growth responses of different rhizobium japonicum strains to increasing temperatures, determine the degree of variability among strains in those responses, and identify temperature-related growth characteristics that could be used to select temperature-tolerant strains. each of 42 strains was grown in liquid culture for 96 h at 19 incubation temperatures ranging from 27.4 to 54.1 degrees c in a temperature gradient apparatus. growth was estimated by measuring ... | 1981 | 16345827 |
| survival of rhizobium in acid soils. | a rhizobium strain nodulating cowpeas did not decline in abundance after it was added to sterile soils at ph 6.9 and 4.4, and the numbers fell slowly in nonsterile soils at ph 5.5 and 4.1. a strain of r. phaseoli grew when added to sterile soils at ph 6.7 and 6.9; it maintained large, stable populations in soils of ph 4.4, 5.5, and 6.0, but the numbers fell markedly and then reached a stable population size in sterile soils at ph 4.3 and 4.4. the abundance of r. phaseoli added to nonsterile soil ... | 1981 | 16345909 |
| cell surface carbohydrates of agrobacterium tumefaciens involved in adherence during crown gall tumor initiation. | 1981 | 7271806 | |
| [microstructure of pea nodules infected with a neomycin-resistant mutant of nodule bacteria]. | the neomycin-resistance mutation of pea nodule bacteria does not interfere with the formation of infection threads when the bacterium inoculates the host plant, or with the axial differentiation of the nodular tissue. at the same time, intracellular neomycin-resistant nodule bacteria do not acquire the bacteroid structure. once the bacterium is incorporated into the cytoplasm of the host cell, it loses the peribacteroid membrane and undergoes lysis. therefore, the neomycin-resistant pea nodule b ... | 1981 | 7278721 |
| transcription of the agrobacterium ti plasmid in the bacterium and in crown gall tumors. | 1981 | 7280084 | |
| nonmutagenic activity of the nitroprusside. | the mutagenic activity of the pentacyanonitrosylferrate (ii) (np) was studied by the prophage induction and the drosophila mosaic test. on the basis of plaque and mosaic spot induction freqauencies it is concluded that both np and its adenine complex are nonmutagenic as for induction of chromosome breaks and point mutations. the nonmutagenic activity of the np can be attributed to its nonpermeability through cell membranes. | 1981 | 7282210 |
| succinate transport in rhizobium leguminosarum. | the transport of succinate was studied in an effective streptomycin-resistant strain of rhizobium leguminosarum. high levels of succinate transport occurred when cells were grown on succinate, fumarate, or malate, whereas low activity was found when cells were grown on glucose, sucrose, arabinose, or pyruvate as the sole carbon source. because of the rapid metabolism of succinate after transport into the cells, a succinate dehydrogenase-deficient mutant was isolated in which intracellular succin ... | 1981 | 7287623 |
| light and electron microscopic studies of nodule structure of alfalfa. | light and electron microscopy was used to establish the structural organisation of the developing nodule of alfalfa. in these nodules three distinct regions were noted: (1) the base region, site of original infection where the nodule is attached to the root and now composed of degenerating nodule tissue, (2) the central region, or active region composed of nodule cells containing tightly packed bacteroids surrounding a central vacuole, and (3) the meristematic region, a site of new growth, behin ... | 1981 | 7214231 |
| [bacterial population dynamics in a soil--plant system]. | the dynamics of rhizobium leguminosarum and arthrobacter crystallopoietes populations introduced into soil at different levels of density was studied in a zone near barley roots. microbial life with a high rate of growth was found only at the root surface. for a. crystallopoietes, the ultimate bacterial incidence at the root surface was found to depend on the original level of population density. for rh. leguminosarum, the ultimate incidence was shown to reach an identical level irrespective of ... | 1981 | 7219211 |
| [relationship between the dynamics of the numbers of nodule bacteria in the soil and the stage of microbial succession]. | the survival of a population of nodule bacteria after its introduction into soil depends on the ratio between favourable and unfavourable microzones. this ratio does not remain constant in one and the same soil at different stages of microbial succession even if the succession is caused by simple humidification of the soil without any introduction of additional substrates. the dynamics of the incidence of nodule bacteria introduced, at one and the same level, into soil samples of different growt ... | 1981 | 7219215 |
| the amino acid composition of rhizobium meliloti flagellin: occurrence of a single tryptophan residue. | 1981 | 7295319 | |
| genetic transformation of rhizobium meliloti by plasmid dna. | a procedure for the genetic transformation of rhizobium meliloti by plasmid dna is described. it is an adaptation of a procedure used originally for escherichia coli and later for agrobacterium tumefaciens. depending on the r. meliloti isolate used as the recipient, the efficiency of transformation was in the range of 7 x 10(1) to 3.7 x 10(3) per microgram of plasmid prk248 dna and 10(-6) to 10(-9) per viable cell. a number of different naturally occurring strains could be transformed. plasmids ... | 1981 | 7297855 |
| competitive advantage provided by bacterial motility in the formation of nodules by rhizobium meliloti. | the effect of motility on the competitive success of rhizobium meliloti in nodule production was investigated. a motile strain formed more nodules than expected when mixed at various unfavorable ratios with either flagellated or nonflagellated nonmotile derivatives. we conclude that motility confers a selective advantage on rhizobia when competing with nonmotile strains. | 1981 | 7298580 |
| bacterial attachment as related to cellular recognition in the rhizobium-legume symbiosis. | bacterial attachment is viewed as a cellular recognition event during the infection of legumes by the nitrogen-fixing symbiont, rhizobium. studies on the biochemical basis of selective attachment are reviewed, and suggest that this recognition process is accomplished by specific glycoprotein lectin-polysaccharide interactions on the surfaces of the symbionts. an understanding of host specificity may lead to ways to broaden the host range of nitrogen-fixing symbioses. | 1981 | 7299839 |
| distribution of cytokinin-active nucleosides in isoaccepting transfer ribonucleic acids from agrobacterium tumefaciens. | the cytokinin-active isoprenoid nucleosides of agrobacterium tumefaciens transfer ribonucleic acid were identified by high-pressure liquid chromatography, permethylation, and mass spectroscopy. besides the expected 6-[(3-methylbut-2-enyl)amino]-9-(beta-d-ribofuranosyl)purine (i6a) and its 2-methylthio derivative (ms2i6a), substantial amounts of cis- and trans-ribosylzeatin (io6a) and cis-2-(methylthio)ribosylzeatin (c-ms2io6a) were present. these hydroxylated side chain derivatives are normally ... | 1981 | 7306490 |
| agrobacterium tumefaciens rna polymerase: a new purification procedure and a study of the stable binding sites on homologous deoxyribonucleic acid. | rna polymerase (rna nucleotidyltransferase, ec 2.7.7.6) of agrobacterium tumefaciens has been purified according to a fast and efficient procedure. the method involves only two chromatographic steps and yields a highly active enzyme. the rna polymerase was studied with respect to the ability to bind its homologous genome. a. tumefaciens deoxyribonucleic acid (dna) binds the enzyme even when fragmented at undergenic size (300 base pairs). the general binding is unspecific and very labile at low c ... | 1981 | 7306497 |
| cellular glycogen, beta-1,2,-glucan, poly beta-hydroxybutyric acid and extracellular polysaccharides in fast-growing species of rhizobium. | synthesis of acidic exopolysaccharides, neutral cellular polysaccharides and poly-beta-hydroxybutyric acid (phb) by rhizobium is strongly dependent on cultural conditions and the strains used. exopolysaccharide production by r. leguminosarum, r. phaseoli and r. trifolii closely parallels growth, whereas r. meliloti mainly excretes (low mol wt) polysaccharides when cell propagation is limited by lack of a necessary growth element (nitrogen) and an excess of carbon source is still present in the m ... | 1981 | 7337433 |
| elaboration of cellulose fibrils by agrobacterium tumefaciens during attachment to carrot cells. | the attachment of virulent strains of agrobacterium tumefaciens to plant cells is the first step in the bacterial induction of tumors. binding of a. tumefaciens to carrot tissue culture cells occurred as a two-step process. the initial step was the attachment of the bacteria to the plant cell wall. living plant cells were not required. bacterial attachment to heat-killed or glutaraldehyde-fixed carrot cells proceeded with only slightly altered kinetics and unaltered bacterial strain specificity. ... | 1981 | 7462151 |
| [spectral studies of the cytochrome p-450 of rhizobium lupini bacteroids]. | 1981 | 7460755 | |
| retention of tumor markers in f1 progeny plants from in vitro induced octopine and nopaline tumor tissues. | tumorous tobacco shoots have been derived from callus tissues produced by agrobacterium tumefaciens--induced transformation of tobacco protoplasts and by fusion of normal protoplasts with those from crown gall tumors. the continued presence of t-dna sequences in shoots is directly demonstrated by southern blotting and is also revealed by the presence of the tumor markers octopine and nopaline. when grafted onto normal tobacco plants, both octopine- and nopaline-type shoots (including those from ... | 1981 | 7249079 |
| the isolation and characterization of a root lectin from soybean (glycine max (l), cultivar chippewa). | a lectin has been isolated from the roots of 5-day soybean (glycine max (l) cultivar chippewa) seedlings, and its properties have been compared to those of the soybean seed lectin. the sugar-binding activities of the two lectins, both in terms of specific hemagglutinating activity and sugar specificity, are indistinguishable. molecular properties of the two lectins, measured as relative molecular weights, isoelectric and electrophoretic patterns, amino acid compositions, immunochemical cross-rea ... | 1981 | 7198118 |
| induction and expression of nodule-specific host genes in effective and ineffective root nodules of soybean. | 1981 | 7194687 | |
| regulation of the expression of leghaemoglobin genes in effective and ineffective root nodules of soybean. | the expression of leghaemoglobin genes in effective and ineffective (unable to fix nitrogen) root nodules of soybean developed by rhizobium japonicum strains 61a76, 61a24 and sm5 was measured by using a cdna probe or a cloned leghaemoglobin sequence and in vitro translation of lb-mrna. hybridization of the poly(a)-containing nodule polysomal rna from 3-week-old nodules with a kinetically purified lb-cdna or with plasmid (plbl) containing a leghaemoglobin sequence showed that lb-mrna is present i ... | 1981 | 7194688 |
| a coupled transcription-translation system from agrobacterium tumefaciens and its application to study ti plasmid expression in vitro. | a coupled transcription-translation system was isolated from a. tumefaciens. expression of plasmids pbr322 and pkt212 from e.coli, cloned fragments of ti plasmid (plasmids pss155 and pss156) and ti plasmid derivatives pal2802, pal2811, pal2821 and pal2832 was analysed in an a. tumefaciens cell-free system and compared with their expression in an e.coli cell-free system. new proteins of 41k and 44k appeared in a tumefaciens extracts, as the result of ti plasmid expression. these proteins were not ... | 1981 | 7038628 |
| localization and partial characterization of soybean lectin-binding polysaccharide of rhizobium japonicum. | immunoelectron microscopy was combined with partial characterization of isolated exopolysaccharide to study binding of soybean lectin by rhizobium japonicum strain usda 138. lectin-binding activity resided in two forms of exopolysaccharide produced during growth: an apparently very high-molecular-weight capsular form and a lower-molecular-weight diffusible form. at low-speed centrifugation, the capsular form cosedimented with cells to form a viscous, white, cell-gel complex which was not diffusi ... | 1981 | 7193204 |
| kinetic mechanism of the hydrogen-oxidizing hydrogenase from soybean nodule bacteroids. | the kinetic mechanism of the unidirectional h2-oxidizing hydrogenase from soybean nodule bacteroids has been investigated with highly purified enzyme. measurements of the km for h2 vary from 0.97 to 2.6 microm, and the km for methylene blue varies from 6 to 17 microm. with h2 and methylene blue as substrates, the initial velocity patterns are intersecting. high levels of methylene blue are inhibitory (ki =2.4 mm): the inhibition is competitive vs. h2. co is a competitive inhibitor of h2 (ki = 15 ... | 1981 | 7016176 |
| agricultural microbiology. | 1981 | 7025197 | |
| genetics and regulation of nitrogen fixation. | 1981 | 7027900 | |
| plasmids specifying plant hyperplasias. | 1981 | 7027906 | |
| presence of trifoliin a, a rhizobium-binding lectin, in clover root exudate. | trifoliin a, a rhizobium-binding glycoprotein from white clover, was detected in sterile clover root exudate by a sensitive immunofluorescence assay employing encapsulated cells of rhizobium trifolii 0403 heat-fixed to microscope slides. its presence in root exudate was further examined by immunoaffinity chromatography. the binding of trifoliin a to cells was specifically inhibited by the hapten, 2-deoxyglucose. significantly higher quantities of trifoliin a were detected in root exudate of seed ... | 1981 | 7029001 |
| a simple and sensitive method for assay of a ribonuclease reductase system. | 1981 | 7030133 | |
| plasmid transfer within and between serologically distinct strains of rhizobium japonicum, using antibiotic resistance mutants and auxotrophs. | methionine-requiring and pantothenic acid-requiring auxotrophs of rhizobium japanicum usda 31, as well as highly antibiotic-resistant mutants of r. japonicum strains usda 31, usda 110, usda 138, and webster 48, were isolated. these mutants were used to transfer the p-1 group plasmids r68.45 and rp4 within and between strains usda 31, usda 110, and webster 48. attempts to demonstrate transfer of either plasmid to strain usda 138 were unsuccessful. | 1981 | 7007335 |
| large plasmids of fast-growing rhizobia: homology studies and location of structural nitrogen fixation (nif) genes. | a single large plasmid was isolated from multiplasmid-harboring strains rhizobium leguminosarum 1001 and r. trifolii 5. these single plasmids, as well as the largest plasmid detectable in r. phaseoli 3622, hybridized with part of the nif structural genes of klebsiella pneumoniae. in contrast, the plasmids of r. meliloti strains v7 and l5-30 did not show hybridization with the nif genes of k. pneumoniae, indicating that these genes might be located either on the chromosome or on a much larger pla ... | 1981 | 7009569 |
| rapid procedure for detection and isolation of large and small plasmids. | procedures are described for the detection and isolation of plasmids of various sizes (2.6 to 350 megadaltons) that are harbored in species of agrobacterium, rhizobium, escherichia, salmonella, erwinia, pseudomonas, and xanthomonas. the method utilized the molecular characteristics of covalently closed circular deoxyribonucleic acid (dna) that is released from cells under conditions that denature chromosomal dna by using alkaline sodium dodecyl sulfate (ph 12.6) at elevated temperatures. protein ... | 1981 | 7009583 |
| effect of nh4+ on nitrogenase activity in nodule breis and bacteroides from pisum sativum l. | nodule breis and bacteroid preparations were made from pisum sativum l. (cv. trapper) inoculated with a single strain of rhizobium leguminosarum. the detached nodules were triturated under helium flow. the resultant breis could support c2h2 reduction in n-tris[hydroxymethyl]methyl-2-aminoethane-sulfonic acid buffer (tes) without any additions for over an hour. nh4+ was found to inhibit c2h2 reduction and h2 evolution. the inhibition was not dependent on the counterion and was evident immediately ... | 1981 | 6938248 |
| potential effects of thiram on medicago - r. meliloti symbiotic association. | the effects of thiram and 2 commercial thiram formulations on the growth and respiration of rhizobia were tested to compare the extent of bacteriostasis under controlled conditions. although bacteriostasis was measurable at all concentrations tested, liquid cultures grew to maximum optical density in thiram suspensions containing less than 10 micrograms/ml. percentage germination, root elongation, and subsequent nodulation by r. meliloti of 2 cultivars of alfalfa, were determined in thiram suspe ... | 1981 | 6942046 |
| the crown-gall potato disk bioassay as a primary screen for compounds with antitumor activity. | a variety of samples consisting of purified compounds (of various origins) and ethanol extracts from plants were assayed for their activity on the growth and initiation of crown-gall tumors on potato disks. the results demonstrated a high correlation between the ability of these compounds to inhibit the initiation and growth of crown-gall tumors on potato disks and their corresponding activity on the mouse p388 leukemia protocol. of the 21 compounds tested to date, there were two false-positives ... | 1981 | 6944538 |
| nuclear and polysomal transcripts of t-dna in octopine crown gall suspension and callus cultures. | to establish a detailed map of the transcribed parts of the t-dna in two octopine crown gall lines grown in suspension culture, t-dna-derived steady-state nuclear and polysomal rna as well as rna synthesized in isolated nuclei purified from the crown gall tissues, was analyzed by southern blot hybridization to specific fragments of the t-region of the octopine plasmid pti ach5. in addition total rna isolated from the same lines grown as callus tissue on solid agar, was analyzed for t-dna specifi ... | 1981 | 6945473 |
| mendelian transmission of genes introduced into plants by the ti plasmids of agrobacterium tumefaciens. | insertion of the bacterial transposon tn7 was used to obtain mutants of an octopine ti plasmid. crown gall tumours induced on tobacco by an agrobacterium tumefaciens strain carrying a particular mutant ti plasmid (pgv2100) were found to give rise to shoots. these shoots were grown in vitro and one of them (rgv-1) was found to contain the t-dna specific enzyme lysopine dehydrogenase (lpdh) and to form roots. after transfer to soil, rgv-1 developed into a morphologically and functionally normal to ... | 1981 | 6948997 |
| location of nodulation and nitrogen fixation genes on a high molecular weight plasmid of r. meliloti. | r. meliloti strain 41 (rm41) was shown to harbour two indigenous plasmids with molecular weights of 140 mdal (prme41a) and more than 300 mdal (prme41b), respectively. using a heat-treatment procedure, derivatives of rm41 defective in nodulation (nod-) or nitrogen fixation (fix-) have been readily obtained. in some nod- mutants the deletion of a segment of plasmid prme41b was found. based on the demonstrated homology between the nitrogen fixation (nif) genes of klebsiella pneumoniae and of r. mel ... | 1981 | 6949000 |
| genes controlling early and late functions in symbiosis are located on a megaplasmid in rhizobium meliloti. | large plasmids of molecular weight varying from 90 to around 200 x 10(6) have earlier been detected in most rhizobium meliloti strains using an alkaline denaturation - phenol extraction procedure. with a less destructive method (eckardt 1978) it was possible additionally to detect one plasmid of molecular weight clearly greater than 300 x 10(6) (= megaplasmid) in all of twenty-seven r. meliloti strains of various geographical origins and nodulation groupings investigated. four strains (rcr 2011, ... | 1981 | 6949001 |
| root exudates in relation to growth and nitrogenase activity of rhizobium japonicum. | root exudates of cowpea and soybean were collected in aerated water cultures. the ability of these exudates to support nitrogenase activity of r. japonicum was studied on defined media. when a complete nitrogenase-inducing medium was supplemented with concentrated root exudate, there was an increased nitrogenase activity. when the cowpea root exudate was substituted for glutamine or sodium succinate in the medium, nitrogenase activity was not detected. growth was good when the root exudate was s ... | 1981 | 6949404 |
| induction of nitrogenase in moong bean rhizobium under cultural conditions. | 1981 | 6951806 | |
| site-specific insertion of genes into t-dna of the agrobacterium tumor-inducing plasmid: an approach to genetic engineering of higher plant cells. | this paper presents a method for insertion of genetic material into a specific site in t-dna, the portion of agrobacterium tumor-inducing (ti) plasmid that becomes incorporated into the nuclear dna of transformed plant cells when crown gall tumors are incited by this plant pathogen. the three stages of our procedure are as follows: 1. a t-dna subfragment cloned in pbr322 is cleaved by a restriction endonuclease at a unique central site and target dna (a kanamycin resistance marker) is ligated in ... | 1981 | 6955419 |
| site-specific mutagenesis of agrobacterium ti plasmids and transfer of genes to plant cells. | a general method is described for the use of tumor-inducing (ti) plasmids as experimental gene-vectors for plant cells. intermediate vectors, containing specific ti plasmid sequences and capable of replication in both e. coli and agrobacterium strains, were constructed and used for the in vitro introduction of isolated dna fragments into predetermined sites of the t-region derived fragments. site-specific inserts and/or deletions-substitutions in ti plasmids were produced by exchange of the modi ... | 1981 | 7050279 |
| [genetic analysis of rhizobium japonicum]. | 1981 | 6780290 | |
| rhizobium japonicum mutant strains unable to grow chemoautotrophically with h2. | rhizobium japonicum strain sr grows chemoautotrophically on a mineral salts medium when incubated in an h2- and co2-containing atmosphere. mutant strains unable to grow or that grow very poorly chemoautotrophically with h2 have been isolated from strain sr. the mutant isolation procedure involved mutagenesis with ethyl methane sulfonate, penicillin selection under chemoautotrophic growth conditions, and plating of the survivors onto medium containing carbon. the resulting colonies were replica p ... | 1981 | 6780521 |
| revertible hydrogen uptake-deficient mutants of rhizobium japonicum. | we have developed mutants of rhizobium japonicum which are deficient in h2 uptake capacity (hup-) and which spontaneously revert to the parent type at a frequency consistent with that of a single-point mutation (ca. 1.0 x 10(-09)). the mutagenesis by nitrous acid and the selection of the hup- phenotype by using penicillin and chemolithotrophy as enrichment for chemolithotrophy-deficient strains are described. two mutants retain low but reproducible levels of ribulose bisphosphate-dependent co2 f ... | 1981 | 6783623 |
| introduction of bacteriophage mu into bacteria of various genera and intergeneric gene transfer by rp4::mu. | the host range of coliphage mu was greatly expanded to various genera of gram-negative bacteria by using the hybrid plasmic rp4::mu cts, which is temperature sensitive and which confers resistance to ampicillin, kanamycin, and tetracycline. these drug resistance genes were transferred from escherichia coli to members of the general klebsiella, enterobacter, citrobacter, salmonella, proteus, erwinia, serratia, alcaligenes, agrobacterium, rhizobium, pseudomonas, acetobacter, and bacillus. mu phage ... | 1981 | 6450749 |
| relationship of siderophore-mediated iron assimilation to virulence in crown gall disease. | three classes of mutants defective in the biosynthesis of the siderophore agrobactin were isolated from agrobacterium tumefaciens a217 after n-methyl-n'-nitro-n-nitrosoguanidine mutagenesis. class i mutants produced uniquely the catechol 2,3-dihydroxybenzoic acid, whereas classes ii and iii produced no detectable catechol. class ii differed from class iii mutants in that exogenous 2,3-dihydroxybenzoic acid was utilized only by the former to synthesize agrobactin. growth of strains b6 and a217, u ... | 1981 | 6455414 |
| a general method for site-directed mutagenesis in prokaryotes. | the genetic analysis of genes from prokaryotic species for which experimental genetic systems have not yet been developed is often limited by the difficulty of producing mutations in those genes. we report here a general technique applicable to gram-negative prokaryotes for site-directed mutagenesis of cloned dna fragments which we have applied to the study of the symbiotic nitrogen fixation genes of rhizobium meliloti. in particular, we mutagenized cloned r. meliloti restriction fragments in es ... | 1981 | 6256652 |
| properties of six pesticide degradation plasmids isolated from alcaligenes paradoxus and alcaligenes eutrophus. | biophysical and genetic properties of six independently isolated plasmids encoding the degradation of the herbicides 2,4-dichlorophenoxyacetic acid and 4-chloro-2-methylphenoxyacetic acid are described. four of the plasmids, pjp3, pjp4, pjp5, and pjp7, had molecular masses of 51 megadaltons, belonged to the incp1 incompatibility group, and transferred freely to strains of escherichia coli, rhodopseudomonas sphaeroides, rhizobium sp., agrobacterium tumefaciens, pseudomonas putida, pseudomonas flu ... | 1981 | 6257648 |
| physical mapping of dna base sequence homologies between an octopine and a nopaline ti plasmid of agrobacterium tumefaciens. | 1981 | 6276566 | |
| further insight on the transferred-dna of octopine crown gall. | six octopine tumour lines incited by ptib6s3, ptiach5 and ptia6 on tobacco, arabidopsis and petunia were studied by the southern blotting hybridisation technique in order to define accurately the dimensions of the segments of plasmid origin transferred to the tumourous cell and their organisation in the plant genome. emphasis has been put on the comparison between octopine and nopaline t-dnas and on the lines presented here compared with those studied previously (thomashow et al. 1980). the leng ... | 1981 | 6276681 |
| relationship between the limited and wide host range octopine-type ti plasmids of agrobacterium tumefaciens. | the relationship between the limited host range octopine ti plasmids and the wide host range octopine ti plasmids ptib6806 and ptia6 was studied. the limited host range ti plasmids shared extensive deoxyribonucleic acid homology; ptiag63 and ptiag162 were essentially completely homologous with ptiag158 while ptiag57 shared approximately 64% homology with ptiag158. in contrast, the limited host range octopine ti plasmids only shared 6 to 15% homology with the wide host range octopine ti plasmid p ... | 1981 | 6260751 |
| dna topoisomerase from agrobacterium tumefaciens: purification and catalytic properties. | the dna topoisomerase from agrobacterium tumefaciens has been purified to apparent homogeneity. the enzyme is a single polypeptide of about 100,000 in molecular weight. no apparent separation of the nicking and sealing activities could be obtained in attempts to separate the two activities by a variety of methods, including limited protease digestion, thermal denaturation, and differential inhibition. monoclonal antibodies obtained from hybridomas likewise did not preferentially inhibit one of t ... | 1981 | 6262720 |
| [adenosine-3':5'-monophosphate phosphodiesterase from rhizobium]. | the phosphodiesterase (pde) activity of adenosine-3':5'-monophosphate was detected in the cells of tubercular bacteria of rhizobium lupini and rhizobium japonicum. the specific activity of three rhizobium forms, e.g. bacteroids from lupine root tubercles, free-nitrogen-fixing culture and vegetative cells grown on a mannitol--yeast agar, were compared. in the bacteroids pde is represented both by soluble and membrane-bound forms. the optimal enzyme activity is revealed in an alkaline medium, wher ... | 1981 | 6263372 |
| substituents at n6 and c-5' control selective uptake and toxicity of the adenine-nucleotide bacteriocin, agrocin 84, in agrobacteria. | the inhibition of a sensitive strain of agrobacterium radiobacter by the nucleotide bacteriocin agrocin 84 has been studied. a structure-function study of the agrocin 84 molecule was undertaken. two agrocin 84 nucleotide fragments lacking either the n6 or 5'-phosphoramidate substituents were used in uptake studies of [32p2]agrocin 84. it was established that the plasmid-controlled, strain-specific uptake of agrocin 84 is determined by the n6-d-glucofuranosyloxyphosphoramidate substituent. this c ... | 1981 | 6263633 |
| fingerprinting and sequence homology of plasmids from different virulent strains of agrobacterium rhizogenes. | 1981 | 6264521 | |
| a rapid one-step method for the isolation of bacteroids from root nodules of soybean plants, utilizing self-generating percoll gradients. | bacteroids were isolated from the nodules of soybean plants by means of self-generating percoll density gradients. the entire procedure can be performed in less than 1 h using an ordinary refrigerated centrifuge and angle head rotor. all of the markers for cytosol and bacteroid fractions behaved in accord with other reports in the literature. asparaginase, beta-hydroxybutyrate dehydrogenase, and alanine dehydrogenase were all localized in the bacteroid fraction. invertase, phosphoenolpyruvate ca ... | 1981 | 6265049 |
| molecular genetic analysis of klebsiella pneumoniae nitrogen-fixation (nif) genes. | 1981 | 6266743 | |
| grown gall plant tumors of abnormal morphology, induced by agrobacterium tumefaciens carrying mutated octopine ti plasmids; analysis of t-dna functions. | ti plasmid mutants derived from agrobacterium tumefaciens strain ach5 that induce tumors of abnormal morphology have been analyzed. on tobacco, a. tumefaciens mutant strain lba4060 induces tumors that specifically give rise to shoots. shoots continue to grow from in vitro cultured bacteria-free tumor tissue derived from such tumors. the mutant character is shown to be correlated with the insertion of an a. tumefaciens is element, is60, into the left arm of the t-region of the octopine ti plasmid ... | 1981 | 6266929 |
| the use of transposons to introduce well-defined deletions in plasmids: possibilities for in vivo cloning. | 1981 | 6269129 | |
| energy status, growth and nitrogenase activity in continuous cultures of rhizobium sp. strain cb756 supplied with nh+4 and various rates of aeration. | 1981 | 6269594 | |
| dna sequence homology in rhizobium meliloti plasmids. | plasmids were recovered by an alkaline procedure from six symbiotically effective strains of rhizobium meliloti of diverse geographical origin, reported to harbour only one middle-size large plasmid (ranging from 89 to 143 megadaltons). each purified plasmid was digested with eight restriction endonucleases; cleavage patterns were very complex: only kpni and xbai gave a limited number of bands. fingerprints were very different, whatever the restriction enzyme or the geographical origin of the st ... | 1981 | 6270502 |
| isr1: an insertion element isolated from the soil bacterium rhizobium lupini. | the insertion element isr1 was isolated from the soil bacterium r. lupini. in this strain, isr1 shows a very strong affinity to plasmid rp4. it causes rp4 mutations at the strikingly high frequency of 10(-2) to 10(-1), either by the integration itself or by generating deletions. in e. coli, isr1 seems to be inactive. no evidence could be obtained for a promoter site on isr1 or for an isr1-encoded protein. our results indicate, however, an isr1-specific termination signal for either transcription ... | 1981 | 6271495 |
| the functional organization of the octopine agrobacterium tumefaciens plasmid ptib6s3. | 1981 | 6272338 | |
| restriction endonuclease mapping of the octopine tumor-inducing plasmid ptiach5 of agrobacterium tumefaciens. | 1981 | 6272339 | |
| nucleotide sequence of the r.meliloti nitrogenase reductase (nifh) gene. | the nucleotide sequence of the structural gene (nifh) of nitrogenase reductase (fe protein) from r.meliloti 41 with its flanking ends is reported. the amino acid sequence of nitrogenase reductase was deduced from the dna sequence. the predicted r.meliloti nitrogenase reductase protein consists of 297 amino acid residues, has a molecular weight of 32,740 daltons and contains 5 cysteine residues. the codon usage in the nifh gene is presented. in the 5' flanking region, sequences resembling to cons ... | 1981 | 6273806 |
| behavior of inc-q plasmids in agrobacterium tumefaciens. | 1981 | 6273954 | |
| interspecific plasmid and genomic dna sequence homologies and localization of nif genes in effective and ineffective strains of rhizobium japonicum. | three strains of rhizobium japonicum were examined for the presence of interspecific conserved plasmid-borne dna sequences and the location of their nif dna sequences. strains 61a76 and 110, which both form effective (nitrogen fixing) nodules on soybeans show very low (24%) total dna sequence homology with each other; strain 61a76 contains one plasmid, and strain 110 contains no identifiable plasmids. strain 61a24 which forms ineffective nodules on soybeans shows relatively high (50%) sequence h ... | 1981 | 6286824 |
| genetic analysis of crown gall: fine structure map of the t-dna by site-directed mutagenesis. | 1981 | 6276020 | |
| isolation of ineffective and high-effective mutant strains of rhizobium species using translocatable drug-resistance elements as mutagens. | 1981 | 6167153 | |
| compositional studies on succinoglycan-like extracellular water-soluble rhizobium polysaccharides. | this study reports structural information on extracellular, water-soluble polysaccharides from 5 different strains of rhizobium, viz. r. trifolii j60, r. meliloti j1017, 202, 204 and 207. all the 5 polysaccharides had glucose and galactose in approximate molar ratio of 7:1. methylation analysis revealed that the polysaccharides contained (1 leads to 3), (1 leads to 6), (1 leads to 4), (1 leads to 4, 1 leads to 6)-linked d-glucose residues, (1 leads to 3)-linked d-galactose and non-reducing termi ... | 1981 | 6168173 |
| growth-phase-dependent immunodeterminants of rhizobium trifolii lipopolysaccharide which bind trifoliin a, a white clover lectin. | the lipopolysaccharide (lps) from rhizobium trifolii 0403 was isolated at different stages of growth and was examined for its (i) ability to bind a white clover lectin (trifoliin a), (ii) immunochemical properties, and (iii) composition. there was significantly more binding of trifoliin a to purified lps and cells in the early stationary phase than to cells in the exponential phase. immunofluorescence and enzyme-linked immunosorbent assays indicated that new antigenic determinants of the lps app ... | 1981 | 6170630 |
| effect of fungicides on growth and on dna, rna and protein anabolism of a rhizobium sp. | eleven fungicides were examined for their effect on the growth and anabolism of rhizobium sp. in pure culture. of these, only 4 were found to inhibit growth of rhizobia at a concentration as low as 10 micrograms/ml. growth inhibition by these fungicides appeared to be primarily due to inhibition of respiration, although thiophanate and anilazine also affected dna and rna synthesis, respectively. inhibition is, however, transitory and the bacterium has the ability to overcome this initial inhibit ... | 1981 | 6173004 |
| structure of rigid-layer of rhizobium cell wall. i. purification on the peptidoglycan from the cellulose microfibrils. | the bag shaped peptidoglycan layer of rhizobium cell wall was isolated from intact cells after treatment with sodium dodecylsulfate and trypsin, chymotrypsin or pepsin digestion. results of chemical analysis of acid hydrolyzed peptidoglycan revealed beside two amino sugars: glucosamine and muramic acid, three major amino acids; alanine, glutamic acid and 2,6-diaminopimelic acid and also significant amount of glucose. evidence were provided that the polyglucose found in peptidoglycan preparations ... | 1981 | 6179395 |
| structure of the rigid-layer of rhizobium cell wall. ii. evidence for a covalent bond between peptidoglycan and cellodextrins. | covalent linkages between peptidoglycan and cellodextrins in the cell walls of rhizobium were defined by the analysis of lysozyme split products. digestion of peptidoglycan with lysozyme resulted in the liberation, beside disaccharide tetrapeptide fragments composed of glucosamine, muramic acid, alanine, glutamic acid and diaminopimelic acid in a molar ratio 1:1:2:1:1, also significant amounts of glucose and its polymers. the neutral carbohydrates composed of glucose, were further purified and d ... | 1981 | 6179396 |
| the pathways of ammonium assimilation in rhizobium meliloti. | two pathways of ammonium assimilation are known in bacteria, one mediated by glutamate dehydrogenase, the other by glutamine synthetase and glutamate synthase. the activities of these three enzymes were measured in crude extracts from four rhizobium meliloti wild-type strains, 2011, m15s, 444 and 12. all the strains had active glutamine synthetase and nadp-linked glutamate synthase. assimilatory glutamate dehydrogenase activity was present in strains 2011, m15s, 444, but not in strain 12. three ... | 1981 | 6116483 |
| agglutinin from alfalfa necessary for binding and nodulation by rhizobium meliloti. | a protein that specifically agglutinates rhizobium meliloti, the alfalfa root nodule endosymbiont, has been purified from alfalfa seed. material cross-reactive to antiserum prepared against the purified agglutinin is present in all alfalfa varieties that were tested but is absent in corn and other legumes not nodulated by rhizobium meliloti. studies with nonnodulating mutants of this microorganism incapable of binding to alfalfa roots suggest that the agglutinin is responsible for specific recog ... | 1981 | 17780880 |
| succinate dehydrogenase mutant of rhizobium meliloti. | a succinate dehydrogenase mutant strain of rhizobium meliloti was isolated after nitrosoguanidine mutagenesis. it failed to grow on succinate, glutamate, acetate, pyruvate, or arabinose but grew on glucose, sucrose, fructose, and other carbohydrates. the mutant strain showed delayed nodulation of lucerne plants, and the nodules were white and ineffective. a spontaneous revertant strain of normal growth phenotype induced red and effective nodules. | 1982 | 6125502 |
| rhizobium meliloti mutants altered in ammonium utilization. | derivatives of rhizobium meliloti 2011 required trace amounts of glutamate to use ammonium as the nitrogen source for growth, although they could use serine as the sole nitrogen source. specific activities of ammonium assimilatory enzymes were similar to those in strain rm2011. the mutants were deficient in nitrogen fixation. | 1982 | 6125503 |
| biochemical studies on cytoplasmic membranes of agrocin sensitive and resistant strains of agrobacterium tumefaciens. | 1982 | 6184960 | |
| studies on superoxide dismutase activities in virulent and avirulent strains of agrobacterium tumefaciens and also in normal and crown gall tumor cells of bryophyllum calycinum. | superoxide dismutase activity in virulent strains of agrobacterium tumefaciens was found to be higher than that in avirulent strains. polyacrylamide gel electrophoresis revealed two isoenzymes in both these strains. these isoenzymes are suggested to be iron and manganese containing superoxide dismutases. crown gall tumor cells of the plant bryophyllum calycinum were found to have higher superoxide dismutase activity than the normal plant cells. polyacrylamide gel electrophoresis revealed two iso ... | 1982 | 6188336 |
| absence of accumulation of ppgpp and rna during amino acid starvation in rhizobium meliloti. | lack of three different amino acids or treatment with the analogue dl-serine hydroxamate does not induce the accumulation of ppgpp and pppgpp, the 3'-pyrophosphates of gdp and gtp, respectively, in rhizobium meliloti strain 41. surprisingly, rna accumulation is controlled under the above mentioned conditions stringently. moreover, no significant rna accumulation was found during chloramphenicol, tetracycline, and streptomycin treatment, suggesting that r. meliloti, unlike any other bacteria in i ... | 1982 | 6175641 |
| t-dna of pti-15955 from agrobacterium tumefaciens is transcribed into a minimum of seven polyadenylated rnas in a sunflower crown gall tumor. | northern blot hybridization analysis of polysomal polyadenylated rna isolated from sunflower crown gall tumor pscg-15955 demonstrated that a minimum of seven rnas were transcribed from t-dna of pti-15955 from agrobacterium tumefaciens. the sizes of the t-dna transcripts were 1.8, 1.6, 1.5, 1.1, 1.0 kilo bases (kb) and two transcripts of 0.8 kb long. the relative abundance of these polyadenylated rnas varied greatly, the 1.0 kb rna being the most abundant and the 1.6 kb rna being the least abunda ... | 1982 | 6175956 |