| molecular cloning of overlapping segments of the nopaline ti-plasmid ptic58 as a means to restriction endonuclease mapping. | | 1980 | 6100893 |
| the functional organization of the nopaline a. tumefaciens plasmid ptic58. | | 1980 | 6100894 |
| dnag-suppressing variants of r68.45 with enhanced chromosome donating ability in rhizobium. | | 1980 | 6100901 |
| molecular mechanism of ti plasmid mobilization by r plasmids: isolation of ti plasmids with transposon-insertions in agrobacterium tumefaciens. | | 1980 | 6100904 |
| localization of the replication control region on the physical map of the octopine ti plasmid. | a series of small plasmids has been derived from the octopine plasmid pti-b6 by in vitro manipulation. the smallest plasmid that is able to replicate in agrobacterium tumefaciens contains the ampicillin-resistance determinant from tn1, coupled to a piece of dna that is homologous to hpai fragment number 11 of the octopine ti plasmid pti-ach 5. the incompatibility functions are also specified by this region. | 1980 | 6100931 |
| identification of two glutamine synthetases in agrobacterium. | two distinct glutamine synthetases have been identified in agrobacterium and in the fast-growing rhizobia. a limited survey indicates that gsii may be found only in the rhizobiaceae family. | 1980 | 6102556 |
| physiological roles of glutamine synthetases i and ii in ammonium assimilation in rhizobium sp. 32h1. | the two glutamine synthetases of rhizobium sp. 32h1 appear to be structurally and functionally distinct. glutamine synthetase i was reversibly adenylylated, and its synthesis was repressed only twofold by ammonium. when in the unadenylylated configuration, it was the enzyme which allowed the organism to grow, albeit marginally, on ammonium as a nitrogen source. there is no evidence to suggest that the second enzyme, glutamine synthetase ii, is regulated by adenylylation. however, this enzyme was ... | 1980 | 6102559 |
| purification of glutamine synthetase from a variety of bacteria. | we have developed two procedures which allow the very rapid purification of glutamine synthetase (gs) from a diverse variety of bacteria. the first procedure, based upon differential sedimentation, depends upon the association of gs with deoxyribonucleic acid in cell extracts. the second procedure, derived from the method of c. gross et al (j. bacteriol. 128:382-389, 1976) for purifying ribonucleic acid polymerase by polyethylene glycol (peg) precipitation, enabled us to obtain high yields of gs ... | 1980 | 6102984 |
| ammonium assimilation in rhizobium meliloti. | we have characterized a mutant of rhizobium meliloti strain 2011 which cannot use ammonium as a nitrogen source. this mutant, rtm2620, was found to have significantly altered glutamate synthase activity. both the mutant and the wild-type strains had glutamate dehydrogenase activity, which, although stimulated in the presence of glutamate and ammonium, was apparently insufficient to allow ammonium assimmilation. we conclude that the glutamine synthetase-glutamate synthase pathway may be the norma ... | 1980 | 6106011 |
| comparative properties of glutamine synthetases i and ii in rhizobium and agrobacterium spp. | some properties of glutamine synthetase i (gsi) and gsii are described for a fast-growing rhizobium sp. (rhizobium trifolii t1), a slow-growing rhizobium sp. (rhizobium japonicum usda 83), and agrobacterium tumefaciens c58. gsii of the fast-growing rhizobium sp. and gsii of the agrobacterium sp. were considerably more heat labile than gsii of the slow-growing rhizobium sp. as previously shown in r. japonicum 61a76, gsi became adenylylated rapidly in all species tested in response to ammonium. gs ... | 1980 | 6107288 |
| the interaction of agrobacterium ti-plasmid dna and plant cells. | the tumour-inducing plasmids of agrobacterium tumefaciens (ti-plasmids) reveal several interesting properties. they are catabolic plasmids, which, instead of rendering agrobacterium strains capable of catabolizing compounds found in nature, force a plant to synthesize these catabolites (denoted 'opines'). this situation is obtained by insertion of a segment of the ti-plasmid (the t-dna) into the plant nucleus, where t-dna genes become expressed and intervene in the biosynthesis of these opines. ... | 1980 | 6109298 |
| 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 |
| 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 |
| promoters regulated by the glng (ntrc) and nifa gene products share a heptameric consensus sequence in the -15 region. | we have determined the nucleotide sequences of the klebsiella pneumoniae nifl (regulation of n2 fixation genes) and the escherichia coli glna (glutamine synthetase) promoters. we compared these sequences with the published sequences of three other promoters that, like the nifl and glna promoters, are activated by the general nitrogen regulators glnf (ntra) and glng (ntrc). the three promoters are the argtr (arginine transport) and dhua (histidine transport) promoters of salmonella typhimurium an ... | 1983 | 6133280 |
| cloning of the glutamine synthetase i gene from rhizobium meliloti. | glutamine synthetase is a major enzyme in the assimilation of ammonia by members of the genus rhizobium. two forms of glutamine synthetase are found in members of the genus rhizobium, a heat-stable glutamine synthetase i (gsi) and a heat-labile gsii. as a step toward clarifying the role of these enzymes in symbiotic nitrogen fixation, we have cloned the structural gene for gsi from rhizobium meliloti 104a14. a gene bank of r. meliloti was constructed by using the bacteriophage p4 cosmid pmk318. ... | 1983 | 6137474 |
| rhizobium sp. strain ors571 ammonium assimilation and nitrogen fixation. | among rhizobia studied, rhizobium sp. strain ors571 alone grew unambiguously on n2 as sole n source. in ors571 , only the glutamine synthetase (gs)-glutamate synthase ( gogat ) pathway assimilated ammonium. however, ors571 exhibited two unique physiological aspects of this pathway: ors571 had only gs i, whereas all other rhizobiaceae studied had both gs i and gs ii, and both nadph- and nadh-dependent gogat activities were present. ors571 gs-affected and nadph- gogat -affected mutant strains were ... | 1984 | 6144666 |
| mg2+ adenosine triphosphatase from cell envelopes of free-living and bacteroid forms of rhizobium lupini strain nzp2257. | a procedure for the purification of mg2+ adenosine triphosphatase (ec 3.6.1.3) from free-living and bacteroid forms of rhizobium lupini nzp2257 is described. the enzyme was released from cell envelopes using triton x-100 and purified by gel filtration on ultrogel aca 22, followed by preparative gel electrophoresis on agarose. the purified atpase had a molecular weight of about 355,000, as determined from sedimentation coefficients on sucrose gradients. kinetic analysis of activity of the enzyme ... | 1984 | 6146293 |
| glutamine synthetase of phaseolus vulgaris l.: organ-specific expression of a multigene family. | a recombinant plasmid (pcpvngs-01) containing sequences related to glutamine synthetase (gs) has been identified from a cdna library constructed from poly (a)+ rna isolated from root nodules of phaseolus vulgaris l. the identification of this recombinant relied on the observations that: (a) the clone hybridized strongly to purified gs mrna; (b) in hybrid-select translation experiments, the clone selected mrna that produced a polypeptide identical in molecular weight to purified gs subunits which ... | 1984 | 6152282 |
| typing of rhizobium with two different phage dilutions. | the sensitivity of 223 rhizobium strains to 28 phages in concentration 4xrtd and 0.4xrtd was compared. depending on their sensitivity to the different phages the strains were divided into three groups: 1. rhizobium trifolii strains, rhizobium leguminosarum for pea, vetch and horse bean and rhizobium phaseoli, 2. r. trifolii strains and r. leguminosarum for pea and vetch, 3. r. meliloti strains, r. lupini and r. meliloti mutants. the use of 4xrtd distinguished 50 different phage types among the 2 ... | 1980 | 6164253 |
| 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 |
| 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 |
| the map position of sym-plasmid regions expressed in the bacterial and endosymbiotic form of rhizobium leguminosarum. | | 1982 | 6179109 |
| 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 |
| 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 |
| liposomes as carriers for intracellular delivery of nucleic acids. | | 1983 | 6193396 |
| localization of nodulation gene on the chromosome of rhizobium meliloti. | using n-methyl-n'-nitro-n-nitrosoguanidine mutant rm54 of rhizobium meliloti l5-30 defective in the nodulation process (nod-) and in the biosynthesis of adenine was obtained. nod- phenotype of this mutant was not caused by the auxotrophic mutation. the nod gene is located on the chromosome. the wild type strain of r. meliloti and nod- mutant rm54 harbour two indigenous plasmids having a molecular weight of 90 mdal and about 300 mdal. | 1983 | 6194660 |
| symbiotic properties of adenine requiring mutants of rhizobium meliloti strain l5-30. | from the effective and prototrophic rhizobium meliloti strain l5-30 two auxotrophic mutants were isolated: rm4 and rm221. these two mutants required adenine and adenine with thiamine for their growth, respectively. both mutants nodulated lucerne plants ineffectively. electron microscopic observations of the nodule tissue showed that its cells were not occupied by bacteria. prototrophic revertants and transductants of these mutants showed high symbiotic effectiveness. it is assumed that adenine o ... | 1983 | 6194661 |
| characterization of the lipopolysaccharide from the nod mutant of rhizobium trifolii. | lipopolysaccharides (lps) from the non-nodulating rhizobium trifolii 24sm 15 and from the nodulating r. trifolii 24sm 13 were isolated and examined by means of gas-liquid chromatography and mass spectrometry. analysis of lps showed these preparations from both strains examined contained lipid a, 2-keto-3-deoxyoctonate, neutral sugars, amino sugars, and trace amounts of amino acids. in 24sm 13 lps prevailed glucose and rhamnose whereas lps from the non-nodulating strain sm 15 contained mainly man ... | 1983 | 6194662 |
| isolation and characterization of mutants of cowpea rhizobium defective in nitrate uptake system. | in this communication, two mutants of cowpea rhizobium cb756 (nr-18 and nr-23), defective in nitrate uptake system, were described. they failed to grow in a medium where nitrate was the sole source of nitrogen and unable to show nitrate reductase activity in cell suspensions. however, they showed nitrate reductase activity (to the level of wild type) in cell-free extract preparations. thus it appears that in these mutants, the transport genes of nitrate uptake were affected and the synthesis of ... | 1983 | 6194663 |
| chromosomal gene controlling symbiotic nitrogen fixation in rhizobium meliloti l5-30. | auxotrophic rhizobium meliloti strain rm 246 carries two independent mutations: in the biosynthesis of cysteine (cys) and symbiotic nitrogen fixation process (fix). these two mutations were mapped by transduction between his-240 and ade-4 markers. cotransduction frequencies show the following order of genes: his-240 fix-1 cys-246 ade-4. | 1983 | 6194666 |
| molecular characterization of tn5-induced symbiotic (fix-) mutants of rhizobium meliloti. | to investigate the expression of specific symbiotic genes during the development of nitrogen-fixing root nodules, we conducted a systematic analysis of nodule-specific proteins and rnas produced after the inoculation of alfalfa roots with a series of rhizobium meliloti mutants generated by site-directed transposon tn5 mutagenesis. the mutagenized region of the rhizobium genome covered approximately 10 kilobases and included the region encoding the nitrogenase polypeptides. all mutant strains tha ... | 1983 | 6196347 |
| structure of the rigid-layer of rhizobium cell wall. iii. electron microscopic evidence for the cellulose microfibrils association with peptidoglycan sacculi. | the morphology of peptidoglycan layer of rhizobium cell wall was examined by transmission electron microscopy. peptidoglycans were isolated from intact cells after treatment with sodium dodecyl sulfate, extraction with aqueous 45% phenol and then with a mixture of chloroform-methanol. finally rigid layers were digested with trypsin and chymotrypsin. the results indicate the presence of lump or bar-like structures on the surface of the cell shaped peptidoglycan sacculi. evidence is provided sugge ... | 1983 | 6196947 |
| the role of cytosine methylation in the control of nopaline synthase gene expression in a plant tumor. | the ft37/1 tumor line induced by agrobacterium tumefaciens on flax epicotyls contains 22-24 copies of the t-dna encoded nopaline synthase gene per cell. all the gene copies are methylated to some extent but the methylation is not uniform, nor does it reflect the methylation level of the flanking plant dna. this extensive methylation correlates with an extremely low level of expression of the nopaline synthase gene. treatment of the tumor line with the in vivo demethylating drug 5-azacytidine at ... | 1983 | 6198416 |
| map locations of five transcripts homologous to tr-dna in tobacco and sunflower crown gall tumors. | polyadenylated rna from two octopine type tumor lines (e1, pscg-15955) was analyzed by rna blot hybridization and shown to contain five major transcripts homologous to tr dna. in tobacco e1 tissue, the molecular weights of the tr homologous rnas are 1.65 kb, 1.55 kb, 1.45 kb, 1.05 kb, and 0.78 kb. the 5' - and 3'-termini of each of the five e1 tumor transcripts were determined by s1 nuclease hybrid protection mapping. the polarity of transcription for the 0.78, 1.05 and 1.65 kb rnas is from left ... | 1984 | 6200831 |
| evaluation of active versus passive uptake of metabolites by rhizobium japonicum bacteroids. | rhizobium japonicum bacteroids were isolated anaerobically from soybean [glycine max (l.) merr] nodules. the bacteroids, which were capable of acetylene reduction and respiration, were used to study the uptake of metabolites by a method which permits correction for nonspecific adsorption of metabolites and estimation of total cell volume. these determinations permit active uptake to be assessed from metabolite accumulation against a concentration gradient. succinate, malate, alpha-ketoglutarate, ... | 1984 | 6203891 |
| siderophore production by phytopathogenic microbial species. | | 1982 | 6218783 |
| partial purification and properties of membrane-bound atpase in agrobacterium tumefaciens. | | 1982 | 6220646 |
| colorimetric determination of catechol siderophores in microbial cultures. | a highly sensitive spectrophotometric method for the selective detection of catechol compounds such as catechol siderophores (e.g., enterobactin) is described. the basis of the method involves the ability of the vicinal aromatic hydroxyl groups under acidic conditions to bring about a reduction of fe3+ (from ferric ammonium citrate) to fe2+. detection of fe2+ in the presence of fe3+ is made with 1,10-phenanthroline under previously established conditions. the assay mixture is heated at 60 degree ... | 1983 | 6227261 |
| h+/atp stoichiometry of cowpea rhizobium sp. strain 32h1 cells grown under nitrogen-fixing and nitrogen-nonfixing conditions. | the obligate aerobe cowpea rhizobium sp. strain 32h1 in axenic culture is able to fix n2 when grown under 0.2% o2 but not when grown under 21% o2. it was, therefore, of interest to investigate atp synthesis in these cells grown under the two conditions. when respiring in buffers having phs ranging from 6 to 8.5, cells grown under either o2 tension maintained an intracellular ph more alkaline than the exterior. the transmembrane chemical gradient of h+ (delta ph) was essentially the same under bo ... | 1984 | 6237099 |
| cloning and expression in escherichia coli of the tl-dna gene 4 of agrobacterium tumefaciens under the control of the pr promoter of bacteriophage lambda. | a plasmid was constructed that directs expression of the tl-dna gene 4 protein in e. coli. the different steps of the construction were as follows: i) a region of gene 4 encoding the amino-terminal portion of the protein was fused in frame to dna encoding an enzymatically active carboxy-terminal fragment of beta-galactosidase. the hybrid gene was poorly expressed from the upstream lambda pl promoter carried by the vector. ii) in order to generate an efficient procaryotic ribosome binding site, a ... | 1984 | 6241481 |
| a procedure for the isolation and purification of plasmid dna from rhizobium meliloti. | | 1980 | 6244752 |
| hairy root: plasmid encodes virulence traits in agrobacterium rhizogenes. | agrobacterium rhizogenes strain 15834, which incites hairy root disease in plants, harbors three large plasmids: par15834a (107 x 10(6) daltons), par15834b (154 x 10(6) daltons), and par15834c (258 x 10(6) daltons). kanamycin-resistant transconjugants were selected in a cross of kanamycin-resistant derivate of strain 15834 and an avirulent recipient. the transconjugants belonging to one class were virulent and contained all three donor plasmids. these transconjugants also acquired sensitivity to ... | 1980 | 6245060 |
| extensive transcription of foreign dna in a crown gall teratoma. | | 1980 | 6245650 |
| physical mapping of part of the tumorigenic deoxyribonucleic acid (t-dan) region of the tumour-inducing (ti) plasmid from agrobacterium tumefaciens strain c58 [proceedings]. | | 1980 | 6245970 |
| purification and characterization of a ferredoxin from rhizobium japonicum bacteroids. | an eight-iron, eight-sulfur ferredoxin from rhizobium japonicum bacteroids of soybean root nodules has been purified to apparent homogeneity as judged by disc gel electrophoresis. the purification procedure included chromatography on deae-cellulose, bio-gel p-60, and hydroxylapatite. specific activities of several purified preparations of bacteroid ferredoxin ranged from 1700 to 1900 nmol of c2h4 produced . min-1 . mg-1 in the reaction mediating electron transfer between illuminated chloroplasts ... | 1980 | 6246115 |
| the boundaries and copy numbers of ti plasmid t-dna vary in crown gall tumors. | the ti plasmid dna maintained in octopine-type crown gall tumor lines is variable, but always includes at least part of the ti plasmid that maps over the region of hind iii fragment 1 of ptib6-806. the right-hand boundary of transferred dna (t-dna) varies considerably among the three independent tumor lines examined; the left boundary was not located definitively. the t-dna of two sibling clones of the same tumor line, e1 and e9, appears identical. the copy number of t-dna in e9 tumor dna appear ... | 1980 | 6247611 |
| cytochromes c-556 from three genetic races of agrobacterium. purification and comparison of their properties. | 1. the soluble cytochromes c-556 from three strains of agrobacterium tumefaciens, b6, ii chrys and apple 185 have been purified to homogeneity. the strains are representative members of the three main genetic races of agrobacterium. the purity of the final preparations was established by electrophoresis with an without sodium dodecyl sulphate, by analytical isoelectric focusing and ultracentrifugation, and by n-terminal analysis. 2. properties of these cytochromes were compared wih those of cyto ... | 1980 | 6249592 |
| tumor dna structure in plant cells transformed by a. tumefaciens. | crown gall tumors are induced in plants by infection with the soil bacterium agrobacterium tumefaciens. because the tumor induction involves transfer of a portion of the tumor-inducing (ti) plasmid dna from the bacterium to the plant cells, this system is of interest for the study of genetic exchange as well as tumor induction. the boundaries of the transferred dna (t-dna) have been cloned from transformed plant cells of tobacco. detailed mapping with restriction enzymes and nucleotide sequence ... | 1980 | 6251546 |
| biochemical characterization of a fructokinase mutant of rhizobium meliloti. | a double mutant strain (ur3) of rhizobium meliloti l5-30 was isolated from a phosphoglucose isomerase mutant (ur1) on the basis of its resistance to fructose inhibition when grown on fructose-rich medium. ur3 lacked both phosphoglucose isomerase and fructokinase activity. a mutant strain (ur4) lacking only the fructokinase activity was derived from ur3; it grew on the same carbon sources as the parent strain, but not on fructose, mannitol, or sorbitol. a spontaneous revertant (ur5) of normal gro ... | 1980 | 6252186 |
| characterization of tn904 insertions in octopine ti plasmid mutants of agrobacterium tumefaciens. | seven tn904 insertion mutants of pti ach5 affecting agrobacterium tumefaciens virulence were studied. the mutant character was shown to be plasmid borne. four of these mutants were avirulent and carried an insertion in restriction endonuclease hpai fragment 12, a 3.3-megadalton fragment, which therefore appears to be a ti plasmid region essential for virulence. two mutants were attenuated in virulence. the inserts mapped close to hpai fragment 12. one mutant giving rise to small tumors with exce ... | 1980 | 6252198 |
| [effectiveness of symbiotic n2-fixation in leguminous plants, as affected by inoculation with rhizobia, by substrate, n-fertilizing, and 14c-sucrose application (author's transl)]. | cultivation experiments (mitscherlich-vessels, quartz sand, 15n-labelled soil, 15n-fertilizer) showed, that various strains of rhizobium lupini (white and yellow lupines) and of rhizobium leguminosarum (field beans and peas) induced a different n2-fixation of the inoculated plants, the most effective rhizobium strains being 367a, cz, t3, 271 (rh. lupini), and azotogen (rh, leguminosarum). yellow lupines and field bean plants were supplied with n2 from the air considerably better than white lupin ... | 1980 | 6252716 |
| is-like element is8 in rp4 plasmid and its involvement in cointegration. | the structure of the cointegrate plasmids formed by fusion of rp4 and the tumour-inducing plasmid (pti) of agrobacterium tumefaciens was analyzed. in all of the nine independently isolated pti::rp4 cointegrates, the integration occurred at the same site on the rp4 genome. moreover, a 1.2 md (1750 bp) rp4 sequence (is8) was directly repeated at both junction sites of the two replicons. the insertion of rp4 generated deletions, starting from the is8 sequence and extending into the ti part of the c ... | 1980 | 6253354 |
| agrobacterium tumefaciens mutants affected in crown gall tumorigenesis and octopine catabolism. | mutants of agrobacterium tumefaciens which affect virulence or the ability to catabolize octopine were isolated after tn5-induced mutagenesis. of 8,900 colonies tested, 7 mutants with tn5 insertions in a specific region of other ti plasmid unable to catabolize octopine were isolated. thirty-seven mutants affected in tumorigenesis resulted from insertions in the ti plasmid and the agrobacterium chromosome. of these mutations, 12 were chromosomal and 25 mapped on the plasmid. twenty-three mapped w ... | 1980 | 6253441 |
| 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 |
| transposition of tn 1 to the rhizobium meliloti genome. | a derivative of the incp1 plasmid rp4, carrying the thermoinducible prophage mucts62, was obtained in escherichia coli k12 j53 (rp4). it was impossible to maintain the hybrid plasmid rp4::mucts62 in rhizobium meliloti gr4. thus, it was used as a vehicle for introducing the ampicillin-resistant transposon tn1 into the r. meliloti genome. transposition of tn1 did not generate auxotrophic strains, suggesting that the insertion of tn1 into the r. meliloti genome was relatively specific. two chromoso ... | 1980 | 6258027 |
| 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 |
| physical and genetic characterization of symbiotic and auxotrophic mutants of rhizobium meliloti induced by transposon tn5 mutagenesis. | we have physically and genetically characterized 20 symbiotic and 20 auxotrophic mutants of rhizobium meliloti, the nitrogen-fixing symbiont of alfalfa (medicago sativa), isolated by transposon tn5 mutagenesis. a "suicide plasmid" mutagenesis procedure was used to generate tn-5-induced mutants, and both auxotrophic and symbiotic mutants were found at a frequency of 0.3% among strains containing random tn5 insertions. two classes of symbiotic mutants were isolated: 4 of the 20 formed no nodules ... | 1982 | 6274841 |
| clustering of nitrogen fixation (nif) genes in rhizobium meliloti. | a cloned 17.3-kilobase region of the rhizobium meliloti genome with homology to the klebsiella pneumoniae nitrogenase structural genes was studied. limits on the extent of homology were determined. transposon mutagenesis of this region of the genome verified that it contained functional nif genes, some transposon insertions resulted in a defective symbiotic phenotype, whereas others had no noticeable effect on symbiotic competence. the relative position of insertions yielding these two phenotypi ... | 1982 | 6274844 |
| genetic analysis of crown gall: fine structure map of the t-dna by site-directed mutagenesis. | | 1981 | 6276020 |
| the ti plasmids of agrobacterium. | | 1982 | 6276093 |
| 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 |
| carriers in electron transport from molecular hydrogen to oxygen in rhizobium japonicum bacteroids. | an investigation has been conducted to identify electron transport carriers that participate in the oxidation of h2 by h2 uptake-positive strains of rhizobium japonicum bacteroids. we have observed that the reduced form of dibromothymoquinone at a concentration of 0.2 mm strongly inhibited h2 uptake, endogenous respiration, and c2h2 reduction by bacteroid suspensions. reduced dibromothymoquinone, however, failed to inhibit the transfer of electrons from h2 to methylene blue under anaerobic condi ... | 1982 | 6277845 |
| effects of iron deficiency on heme biosynthesis in rhizobium japonicum. | the effects of iron deficiency on heme biosynthesis in rhizobium japonicum were examined. iron-deficient cells had a decreased maximum cell yield and a decreased cytochrome content and excreted protoporphyrin into the growth medium. the activities of the first two enzymes of heme biosynthesis, delta-aminolevulinic acid synthase (ec 2.3.1.37) and delta-aminolevulinic acid dehydrase (ec 4.2.1.24), were diminished in iron-deficient cells, but were returned to normal levels upon addition of iron to ... | 1982 | 6277847 |
| rhizobium japonicum mutants that are hypersensitive to repression of h2 uptake by oxygen. | the synthesis of an h2 oxidation system in free-living rhizobium japonicum wild-type strain sr is repressed by oxygen. maximal h2 uptake rates were obtained in strain sr after derepression in 11 microm or less dissolved oxygen. oxygen levels above 45 microm completely repressed h2 uptake in strain sr. five r. japonicum mutant strains that are hypersensitive to repression or h2 oxidation by oxygen were derived from strain sr. the mutants were obtained by screening h2 uptake-negative mutants that ... | 1982 | 6277861 |
| metal coordination centres of class ii cytochromes c. | the class ii cytochromes rhodospirillum molischianum cytochrome c', rhodopseudomonas palustris cytochrome c556 and agrobacterium tumefaciens (b2a) cytochrome c556 have been investigated with a variety of spectroscopic techniques. the cytochrome c' was found to be high-spin and the two cytochromes c556 were found to be mainly low-spin and sx-coordinate with the fifth and sixth ligands being histidine and methionine. the implications of the different types of iron coordination are discussed. | 1982 | 6279397 |
| transformation of rhizobium meliloti 41 with plasmid dna. | plasmid pgv1106, a derivative of the wide-host-range plasmid s-a of the w incompatibility group, was introduced into rhizobium meliloti 41 by plasmid-mediated mobilization to overcome the restriction of foreign dna. the mobilized plasmid pkk2 differed from the original pgv1106 by an extra piece of dna of 1.3 kilobase pairs which supposedly originated from pjb3ji used for mobilization. if pkk2 was isolated from r. meliloti 41, it could be successfully reintroduced by transformation. the transform ... | 1982 | 6279558 |
| construction and application of r prime plasmids, carrying different segments of an octopine ti plasmid from agrobacterium tumefaciens, for complementation of vir genes. | | 1982 | 6281831 |
| a functional map of the replicator region of the octopine ti plasmid. | | 1982 | 6281832 |
| organization and expression of leghaemoglobin genes. | leghaemoglobin genes in soybean (glycine max) are present as a moderately reiterated family of sequences. since there are identical restriction site patterns of these sequences in dna isolated from leaf, root, or nodule tissue, the data suggest that no major changes in the organization or methylation of leghaemoglobin genes occur during their induction. cloned soybean leghaemoglobin-cdna cross hybridized with rna from root nodules of kidney bean (phaseolus vulgaris), and to a lesser extent, of p ... | 1982 | 6282418 |
| octopine ti-plasmid deletion mutants of agrobacterium tumefaciens with emphasis on the right side of the t-region. | | 1982 | 6283573 |
| restriction endonuclease mapping of a rhizobium leguminosarum sym plasmid. | | 1982 | 6285400 |
| molecular genetics of symbiotic nitrogen fixation. | | 1982 | 6286135 |
| transport and catabolism of d-mannose in rhizobium meliloti. | rhizobium meliloti l5-30 grows on d-mannose as the sole carbon source. the catabolic pathway of d-mannose was characterized. the following activities were present: mannose transport system, mannokinase, and mannosephosphate isomerase. several mannose-negative mutants were selected; they were classified into three functional groups: group i, mannokinase and mannosephosphate isomerase defective: group ii, mannokinase defective; and group iii, mannosephosphate isomerase defective. mannose uptake wa ... | 1982 | 6286588 |
| 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 |
| molecular cloning of rhizobium trifolii genes involved in symbiotic nitrogen fixation. | dna sequences responsible for the development and maintenance of symbiotic nitrogen fixation have been identified and isolated from rhizobium trifolii. symbiotically-defective strains were generated by random mutagenesis with the transposon tn5. the defective genes which give rise to the mutant phenotype have been cloned into bacterial plasmids and used as hybridization probes to isolate the corresponding wild-type genes from a clone bank of r. trifolii dna. symbiotic genes cloned in this manner ... | 1982 | 6286830 |
| genetic map of the crown gall suppressive incw plasmid psa. | a genetic map of the w incompatibility group plasmid psa has been prepared through the construction of deletion derivatives of psa and the cloning of various fragments of psa in pbr322. phenotypic analysis of these derivatives has identified the location of genes encoding resistance to chloramphenicol, sulfonamides, spectinomycin, streptomycin, kanamycin, gentamycin, and tobramycin. information sufficient for the replication of the plasmid in both escherichia coli and agrobacterium tumefaciens i ... | 1982 | 6287164 |