| directed transposon tn5 mutagenesis and complementation analysis of rhizobium meliloti symbiotic nitrogen fixation genes. | an 18 kb region adjacent to and surrounding the genes for nitrogenase (nif) was cloned from the genome of the symbiotic nitrogen-fixing species rhizobium meliloti. a total of 31 tn5 insertions in the nif region were constructed and assayed for their effect on symbiotic nitrogen fixation (fix phenotype). fix- insertions were found in two clusters, one 6.3 kb region not containing essential symbiotic genes. the locations of at least three transcription units containing fix genes were deduced from ... | 1982 | 6288262 |
| electron transport components involved in hydrogen oxidation in free-living rhizobium japonicum. | membranes from free-living rhizobium japonicum were isolated to study electron transport components involved in h2 oxidation. the h2/o2 uptake rate ratio in membranes was approximately 2. the electron transport inhibitors antimycin a, cyanide, azide, hydroxylamine, and 2-n-heptyl-4-hydroxyquinoline-n-oxide (hqno) inhibited h2 uptake and h2-dependent o2 uptake significantly. h2-reduced minus o2-oxidized absorption difference spectra revealed peaks at 551.5, 560, and 603 nm, indicating the involve ... | 1982 | 6288665 |
| on the operon structure of the nitrogenase genes of rhizobium leguminosarum and azotobacter vinelandii. | the transcription of the nitrogenase genes in rhizobium leguminosarum was studied by analysing total cellular rna from bacteroids for the presence of nitrogenase messenger rna. the rna was separated by agarose gel electrophoresis and blotted onto nitrocellulose filters. messenger rna for nitrogenase was detected by hybridization with probes derived from plasmid psa30, a recombinant plasmid carrying the nitrogenase genes of klebsiella pneumoniae. in the same way nitrogenase mrna was detected in r ... | 1982 | 6289264 |
| construction of a broad host range cosmid cloning vector and its use in the genetic analysis of rhizobium mutants. | we have constructed a cosmid derivative of the low copy-number broad host-range cloning vector prk290 (ditta et al., 1980) by inserting a 1.6-kb bg/ii fragment containing lambda cos into the unique bg/ii site in prk290. the new vector, plafr1, is 21.6 kb long, confers tetracycline resistance, contains a unique ecori site, and can be mobilized into and stably replicates within many gram-negative hosts. we constructed a clone bank of rhizobium meliloti dna in plafr1 using a partial ecori digest. t ... | 1982 | 6290332 |
| t-dna organization in homogeneous and heterogeneous octopine-type crown gall tissues of nicotiana tabacum. | octopine-type tumor tissue was obtained both by infection of plants or isolated protoplasts with agrobacterium tumefaciens and by somatic hybridization of normal and crown gall tobacco cells. analysis of t-dna by southern blotting of clones and uncloned tissue reveals that, whereas tumors induced on plants are heterogeneous mixtures of cells differing in t-dna organization, each tissue derived from transformed protoplasts or from somatic hybridization is homogeneous. detailed analysis of t-dna o ... | 1982 | 6291777 |
| agrobacterium tumefaciens mutants affected in attachment to plant cells. | an analysis of agrobacterium tumefaciens mutants with tn5 insertions in chromosomal dna showed that the chromosome of a. tumefaciens codes for a specific ability of this bacterium to attach to plant cells. this ability is associated with tumorigenesis by a. tumefaciens, the ability of avirulent a. tumefaciens to inhibit tumorigenesis, and the ability to adsorb certain phages. a second class of chromosomal mutations affects tumorigenesis without altering the ability to attach to plant cells. the ... | 1982 | 6292165 |
| wide host range cloning vectors: a cosmid clone bank of an agrobacterium ti plasmid. | | 1982 | 6292969 |
| method for the transfer of large cryptic, non-self-transmissible plasmids: ex planta transfer of the virulence plasmid of agrobacterium rhizogenes. | | 1982 | 6292973 |
| microbial envelope proteins related to iron. | | 1982 | 6293371 |
| genetic isolation and physical characterization of pagk84, the plasmid responsible for agrocin 84 production. | | 1982 | 6294705 |
| in vivo packaging of cosmids in transposon-mediated mutagenesis. | a technique was developed that permits the analysis of large regions of dna by transposition mutagenesis. large fragments of the ptia6nc plasmid were cloned into the broad host range cosmid phk17 and subjected to transposition mutagenesis by tn3. cosmids containing tn3 insertions were selected by in vivo packaging by lambda ci857 and transduction to a new host. the insertions were localized by dna restriction endonuclease analysis and transferred to the ti-plasmid by marker exchange. | 1983 | 6296041 |
| localization of symbiotic mutations in rhizobium meliloti. | a total of 5 nod- and 57 fix- symbiotic mutants of rhizobium meliloti strain 41 have been isolated after either nitrosoguanidine or tn5 transposition mutagenesis. chromosomal locations of mutations in 1 nod- and 11 fix- derivatives were ascertained by transferring the chromosome (mobilized by plasmid r68.45), in eight fragments, into symbiotically effective recipients and testing the recombinants for symbiotic phenotype. alternatively, the kanamycin resistance marker of tn5 was mapped. in five m ... | 1983 | 6296048 |
| mutational analysis of the virulence region of an agrobacterium tumefaciens ti plasmid. | forty-nine tn3 and tn5 transposition insertion mutations were introduced into the virulence region of the ptia6nc plasmid of agrobacterium tumefaciens. five tn5 transposition mutations from an earlier study (d. garfinkel and e. nester, j. bacteriol. 144:732-743, 1980) were also mapped more accurately. these mutations defined five separate loci within the virulence region. two tn3 insertions into one of these loci, vira, result in a strain which is only weakly virulent; however, a tn5 insertion i ... | 1983 | 6296058 |
| isrm1: a rhizobium meliloti insertion sequence that transposes preferentially into nitrogen fixation genes. | after transposon tn5 mutagenesis, a high proportion of rhizobium meliloti symbiotic mutants do not contain tn5 insertions in symbiotic genes. instead, the mutations in these strains are correlated with the presence of an endogenous insertion sequence (isrm1) in nitrogen fixation (nif) or symbiotic genes which are adjacent to the nif genes. isrm1 is 1.4 kb and transposes to at least three restriction fragments in the nif region at a frequency between 10(-2) and 10(-3). a nif region restriction fr ... | 1982 | 6296251 |
| symbiotic nitrogen fixation: molecular cloning of rhizobium genes involved in exopolysaccharide synthesis and effective nodulation. | a transposon (tn5)-induced mutant (strain anu437) of rhizobium trifolii was isolated in which no water-soluble exopolysaccharide (eps) could be detected. this mutant was also incapable of forming nitrogen-fixing root nodules on clover plants. molecular cloning has demonstrated that the tn5 transposon was responsible for both of these mutant phenotypes and that there is a direct correlation between eps synthesis in this bacterial strain and its ability to carry out symbiotic nitrogen fixation. in ... | 1982 | 6296257 |
| t-dna of the agrobacterium ti and ri plasmids. | the study of t-dna transmission from agrobacterium ti or ri plasmid into the genomes of higher plant cells has revealed much about the consequences of transformation. it is now clear that the transformed phenotype is caused by hormonal changes produced directly or indirectly by t-dna genes. the opine synthases are enzymes encoded in t-dna that function in the plant cell. our level of understanding of t-dna-encoded functions is already sufficient to reveal clear and feasible ways to exploit t-dna ... | 1982 | 6297376 |
| variation in hormone autonomy and regenerative potential of cells transformed by strain a66 of agrobacterium tumefaciens. | mutant agrobacterium tumefaciens strain a66 is shown to differ from its wild-type progenitor (strain a6) by a spontaneous 2.7 kb dna insert into the t-dna region of its ti plasmid. tobacco stems transformed by a66 exhibit an attenuated response characterized by slow growth and shoot proliferation. clonal analysis demonstrates that this response is due to an alteration in the growth and regenerative potential of transformed cells, rather than to variation in the frequency of fully autonomous cell ... | 1982 | 6297775 |
| the complete amino-acid sequence of the low-spin class ii cytochrome c-556 from agrobacterium tumefaciens strain b2a. | the amino acid sequence of the soluble monohaem cytochrome c-556 from agrobacterium tumefaciens, strain b2a, has been determined. the sequence was derived from peptides obtained by digestion of the apoprotein with trypsin and chymotrypsin, and by subdigestion of some of the peptides with staphylococcus aureus protease and thermolysin. sequencing of the various peptides was achieved by a combination of manual dansyl-edman degradation and automatic liquid-phase sequence analysis. the main characte ... | 1983 | 6297889 |
| transposon-facilitated chromosome mobilization in agrobacterium tumefaciens. | we improved chromosomal gene transfer in agrobacterium tumefaciens strain 15955 by constructing donors containing homologous transposons on both the sex factor plasmid and chromosome. first, we constructed plasmid pdp35, a kanamycin-sensitive derivative of r68.45. we then constructed derivatives of pdp35 that contained insertions of the kanamycin resistance transposon tn5. by restriction endonuclease analysis, we identified two plasmids, pdp37 and pdp38, in which tn5 was inserted in the same reg ... | 1983 | 6298186 |
| comparison of ti plasmids from three different biotypes of agrobacterium tumefaciens isolated from grapevines. | twenty-six plasmids from grapevine isolates of agrobacterium tumefaciens were analyzed by smai fingerprinting and by hybridization of nick-translated dna to dna of another plasmid. these experiments established that octopine ti plasmids are not highly conserved, although octopine ti plasmids from biotype 1 a. tumefaciens strains appeared to be very similar. octopine ti plasmids from biotype 3 strains are more variable in terms of host range and smai fingerprints, but share extensive dna homology ... | 1983 | 6298189 |
| units of genetic expression in the virulence region of a plant tumor-inducing plasmid of agrobacterium tumefaciens. | the effect of a large number of tn3 insertions in the vir region of the ti plasmid ptia6nc on the virulence of agrobacterium was determined. the vir- insertions were mapped in three of the five loci that have been defined previously. merodiploid rec- strains carrying one insertion mutation on the ti plasmid and another insertion mutation (or the homologous wild-type region) on a compatible plasmid were constructed and used in complementation tests for virulence in test plants. this analysis has ... | 1982 | 6298572 |
| structure and transcription of the nopaline synthase gene region of t-dna. | we present the dna sequence and plant-tumor transcription pattern of some 2400 base pairs from the right border region of pti t37 dna from the virulent agrobacterium tumefaciens strain t37. this region includes the entire transcription unit encompassing the nopaline synthase gene, together with parts of other transcription units. the strategy used to determine the sequence also produced two opposing series of defined, asymmetric deletions across the target dna region, some of which may serve fut ... | 1983 | 6298724 |
| [range of the transmissivity of the genetic transfer factors pap38, pap39, pap41 and pap42]. | a study was made of the transmissivity range of the genetic transfer factors pap38, pap39, pap41 and pap42 identified in e. coli. it was demonstrated that these factors are not capable of transfer to the cells of p. putida, p. fluorescens, r. leguminosarum, a. lipoferum, a. tumefaciens. factor pap42 is mobilized to transfer to p. putida and r. leguminosarum with the aid of plasmid rp4. it is assumed that in the course of mobilization, the cointegrative structures are formed between plasmids pap4 ... | 1983 | 6299434 |
| primary structure of the dna-binding protein hrm from rhizobium meliloti. | the amino acid sequence of protein hrm, a dna-binding hu-type protein of 90 residues (mr 9303), isolated from rhizobium meliloti, has been established from automated sequence analysis of the protein and from structural data provided by peptides derived from cleavage of the protein at arginine and aspartic acid residues. the comparison of the primary structure of protein hrm with that of other hu-type proteins shows that two short sequences, of 7 and 6 residues respectively, located in the median ... | 1983 | 6299736 |
| multiple mutations in the t region of the agrobacterium tumefaciens tumor-inducing plasmid. | three genetic loci affecting tumor morphology lie within ptia6nc t-dna: tms, tmr, and tml. using deletions and multiple transposon insertions, we constructed tumor-inducing (ti) plasmids representing every possible double and triple mutant combination. tms tmr and tms tmr tml mutants did not incite tumors on most plants and produced a very weak response on a few other hosts but tms tml and tmr tml mutants were virulent. thus, either tms+ or tmr+ alone can promote significant tumor growth but tml ... | 1983 | 6300864 |
| regeneration of intact tobacco plants containing full length copies of genetically engineered t-dna, and transmission of t-dna to r1 progeny. | cloned dna sequences encoding yeast alcohol dehydrogenase and a bacterial neomycin phosphotransferase have been inserted into the t-dna of agrobacterium tumefaciens plasmid ptit37 at the "rooty" locus. transformation of tobacco stem segments with the engineered bacterial strains produced attenuated crown gall tumors that were capable of regeneration into intact, normal tobacco plants. the yeast gene and entire transferred dna (t-dna) were present in the regenerated plants in multiple copies, and ... | 1983 | 6301678 |
| size, location and polarity of t-dna-encoded transcripts in nopaline crown gall tumors; common transcripts in octopine and nopaline tumors. | up to thirteen t-dna-encoded, polyadenylated transcripts of different relative abundance were detected by northern blot hybridization in the tobacco nopaline bt37 crown gall teratoma tissue. their sizes range from 900 to 2,700 bases. the polarity of eight of the thirteen transcripts was assigned by hybridization of labeled rna to single-stranded dna fragments of the t-region obtained by cloning in an m13 vector. both strands of the t-dna are transcribed. our data indicate that most, if not all, ... | 1983 | 6301679 |
| site-directed mutagenesis in escherichia coli of a stable r772::ti cointegrate plasmid from agrobacterium tumefaciens. | the host range of an octopine ti plasmid is limited to rhizobiaceae. this has been extended also to escherichia coli in the form of a stable cointegrate with the wide-host-range plasmid r772. its structure was studied by constructing a physical map of r772 and of the r772::ptib6 cointegrate. an insertion sequence present in r772, called is70, turned out to be involved in cointegrate formation. we found one intact copy of is70 and a small segment of is70, respectively, at the junctions of r772 an ... | 1983 | 6302080 |
| role of bacterial cellulose fibrils in agrobacterium tumefaciens infection. | during the attachment of agrobacterium tumefaciens to carrot tissue culture cells, the bacteria synthesize cellulose fibrils. we examined the role of these cellulose fibrils in the attachment process by determining the properties of bacterial mutants unable to synthesize cellulose. such cellulose-minus bacteria attached to the carrot cell surface, but, in contrast to the parent strain, with which larger clusters of bacteria were seen on the plant cell, cellulose-minus mutant bacteria were attach ... | 1983 | 6302086 |
| the genetic engineering of nitrogen fixation. | | 1983 | 6302610 |
| ti plasmid and chromosomal ornithine catabolism genes of agrobacterium tumefaciens c58. | the ptic58 plasmid noc genes of agrobacterium tumefaciens c58 code for nopaline oxidase (nocc), nopaline permease (nocp), the inducible periplasmic protein n1 (nocb), and a function(s) required for ornithine catabolism (noca). in addition, strains c58 and ach-5 of a. tumefaciens have chromosomal ornithine catabolism genes. the chromosomal orc gene codes for ornithine dehydrogenase. strain c58 is normally orc, but orc+ mutants can be selected. we have characterized both chromosomal orc and ptic58 ... | 1983 | 6305908 |
| isolation and characterization of the reca gene of rhizobium meliloti. | interspecific complementation of an escherichia coli reca mutant with plasmids containing a gene bank of rhizobium meliloti dna was used to identify a clone which contains the reca gene of r. meliloti. the r. meliloti reca protein can function in recombination and in response to dna damage when expressed in an e. coli reca host, and hybridization studies have shown that dna sequence homology exists between the reca gene of e. coli and that of r. meliloti. the isolated r. meliloti reca dna was us ... | 1983 | 6305915 |
| methylation of the t-dna in agrobacterium tumefaciens and in several crown gall tumors. | methylation of the t-dna in agrobacterium tumefaciens and in four octopine-type (a6s/2, e9, 15955/1, 15955/01) and one nopaline-type (ht37#15) crown gall tumors was investigated using the isoschizomeric restriction endonucleases msp i and hpa ii. t-dna in the octopine-type ti-plasmid ptib6(806) was not methylated at the sequence 5'ccgg3' in agrobacterium. with two possible exceptions, neither was the t-dna of the nopaline-type ti-plasmid ptit37 methylated in the bacterium. in all tumor lines inv ... | 1983 | 6306562 |
| activation of klebsiella pneumoniae and rhizobium meliloti nitrogenase promoters by gln (ntr) regulatory proteins. | we have studied the expression, in different escherichia coli gln (ntr) mutants, of fusions (constructed in vitro) of the nifhdk (nitrogenase) promoters from klebsiella pneumoniae and rhizobium meliloti to e. coli lacz. derepression of the k. pneumoniae nifh::lacz fusion requires the glnf (ntra) gene product in addition to the k. pneumoniae nifa gene product, indicating that regulation of the k. pneumoniae nif genes is more closely integrated with the overall nitrogen control system than previou ... | 1983 | 6306658 |
| nitrogenase structural genes are unlinked in the nonlegume symbiont parasponia rhizobium. | several rhizobium strains are capable of biological nitrogen fixation in symbiotic association with nonleguminous plants. the gene encoding the iron-protein component of nitrogenase (nifh) from one such strain, parasponia rhizobium sp. anu289, has been isolated and completely sequenced. unlike previously studied nitrogen-fixing prokaryotes, the fe-protein subunit is encoded on a separate operon from other components of the nitrogenase enzyme complex. comparative analysis of fe-protein amino acid ... | 1983 | 6307622 |
| biological nitrogen fixation: primary structure of the rhizobium trifolii iron protein gene. | biological nitrogen fixation in the rhizobium-legume symbiosis is dependent on the induction of a bacterially-encoded enzyme complex, nitrogenase. to examine the organization and expression of the genes encoding the components of nitrogenase in this complex system, these genes have been isolated from the legume symbiont rhizobium trifolii by molecular cloning. dna sequence analysis of the entire nifh gene (encoding the fe-protein component of nitrogenase) and of the amino-terminal 141 codons of ... | 1983 | 6307623 |
| in rhizobium japonicum the nitrogenase genes nifh and nifdk are separated. | in contrast to klebsiella pneumoniae or fast-growing rhizobium species, such as r. meliloti, where the nitrogenase structural genes are clustered in one operon (nifhdk), in slow-growing rhizobium japonicum 110, nifh and nifdk are on separate operons. | 1983 | 6307985 |
| nopaline ti-plasmid, ptit37, t-dna insertions into a flax genome. | the ft37/1 plant tumor line induced on flax epicotyls by t37, a nopaline strain of agrobacterium tumefaciens, contains multiple copies of the ptit37, t-dna. there are three to four distinct full-length insertions and one tandem insertion. allowing for the different copy numbers of the inserts, this amounts to seven to eight t-dna copies per genome unit. the genome unit in this case is the haploid dna value (7 x 10(8) bp) which predicts a t-dna copy number of 14-16 per diploid cell. three novel t ... | 1983 | 6308120 |
| expression of bacterial genes in plant cells. | chimeric bacterial genes conferring resistance to aminoglycoside antibiotics have been inserted into the agrobacterium tumefaciens tumor-inducing (ti) plasmid and introduced into plant cells by in vitro transformation techniques. the chimeric genes contain the nopaline synthase 5' and 3' regulatory regions joined to the genes for neomycin phosphotransferase type i or type ii. the chimeric genes were cloned into an intermediate vector, pmon120, and inserted into ptib6s3 by recombination and then ... | 1983 | 6308651 |
| the amino acid sequence of cytochrome c-556 from agrobacterium tumefaciens strain apple 185. | the evidence for the amino acid sequence of cytochrome c-556 from agrobacterium tumefaciens strain apple 185 is reported. the sequence was determined by manual edman degradation of tryptic and chymotryptic peptides using the dabitc/pitc double-coupling method; some peptides were further cleaved by partial acid hydrolysis and with staphylococcus aureus protease. the sequence overlaps 13-15, 83-85 and 106-108 as well as the region 113-118 involving the haem-binding sequence cys-xaa-xaa-cys-his wer ... | 1983 | 6309523 |
| plasmid visualization and nif gene location in nitrogen-fixing azospirillum strains. | a modified gel electrophoresis technique provided a reproducible way of detecting and isolating plasmids with molecular weights ranging from 12 x 10(6) to 370 x 10(6) for azospirillum species. analysis with the nifhd region of rhizobium trifolii showed that the azospirillum nif genes were chromosomally located in all eight strains investigated and not on endogenous plasmids. | 1983 | 6309750 |
| agrobacterium ti plasmids as vectors for plant genetic engineering. | | 1983 | 6310340 |
| tn5 carries a streptomycin resistance determinant downstream from the kanamycin resistance gene. | in rhizobium meliloti, tn5 conferred resistance not only to kanamycin but to streptomycin, as well, in escherichia coli, however only to kanamycin. using in vitro recombinant dna techniques, it was shown that the streptomycin resistance determinant was located downstream from the kanamycin resistance gene in the unique central region of tn5. expression of various cloned fragments of tn5 suggested that both kanamycin and streptomycin resistance genes were transcribed from the same promoter. e. co ... | 1983 | 6312272 |
| nucleotide sequence of the agrobacterium tumefaciens octopine ti plasmid-encoded tmr gene. | the nucleotide sequence of the tmr gene, encoded by the octopine ti plasmid from agrobacterium tumefaciens (ptiach5), was determined. the t-dna, which encompasses this gene, is involved in tumor formation and maintenance, and probably mediates the cytokinin-independent growth of transformed plant cells. the nucleotide sequence of the tmr gene displays a continuous open reading frame specifying a polypeptide chain of 240 amino acids. the 5'- terminus of the polyadenylated tmr mrna isolated from o ... | 1983 | 6312414 |
| a new technique for genetic engineering of agrobacterium ti plasmid. | a new technique is described that allows easy introduction of foreign genetic elements into specific regions of agrobacterium tumefaciens dna. it uses plasmids that (1) can be introduced, but not maintained in a. tumefaciens, (2) have a region homologous to the genome of the recipient, and (3) have an appropriate marker. selection for the marker will yield transconjugants in which the introduced plasmid has recombined with the host genome. applications of the technique are described. | 1983 | 6312475 |
| construction of a broad-host-range kanamycin-resistant plasmid vector. | a new 10.2-kb plasmid, pirl2, was constructed by using a 2140-bp dna fragment carrying the kmr gene and bamhi cohesive ends. these bamhi cohesive ends were used to trap the replicating dna fragment from a partial sau3a digest of the plasmid r300b. the plasmid contains unique ecori, ssti, hindiii, smai, sali, and xhoi sites. these sites can be used as cloning sites without the loss of kmr. a unique bglii site can be used as a cloning site by insertional inactivation of the kmr structural gene, co ... | 1983 | 6313482 |
| transfer of an indigenous plasmid of rhizobium loti to other rhizobia and agrobacterium tumefaciens. | rhizobium loti strains nzp2037 and nzp2213 were each found to contain a single large plasmid: prlo2037a (240 mdal) and prlo2213a (120 mdal), respectively. plasmid dna present in crude cell lysates of each strain and purified prlo2037a dna did not hybridize with pid1, a recombinant plasmid containing part of the nitrogen fixation (nif) region of r. meliloti, indicating that nif genes were not present on these plasmids. the transposon tn5 was inserted into prlo2037a and this plasmid was then trans ... | 1983 | 6313860 |
| recombination deficient mutants of rhizobium meliloti 41. | two mutants deficient in homologous genetic recombination have been isolated from rhizobium meliloti 41 after tn5 mutagenesis. both mutants are defective in the induction of temperate phage 16-3 by uv-light, mytomycin-c or bleomycin, their uv sensitivity is more pronounced than that of the wild-type strain, and they lack the 'sos activity' responsible for induced mutations. | 1983 | 6314090 |
| the detailed physical map of the temperate phage 16-3 of rhizobium meliloti 41. | restriction cleavage maps for enzymes ecori, bamhi, psti, pvuii, xbai and ecorv of rhizobium meliloti temperate phage 16-3 have been established. together with the earlier maps (hindiii, kpni, hpai, bglii) 98 restriction sites, 'evenly' distributed, have been mapped along the phage genome, including the so far unmarked silent region of the chromosome. all the restriction maps have been fitted to each other by computer optimalization. beyond for conventional techniques a computer program (pmap) f ... | 1983 | 6314093 |
| restriction endonuclease mapping of the root-inducing plasmid of agrobacterium rhizogenes 1855. | the root-inducing plasmid of the agropine type agrobacterium rhizogenes 1855 was mapped by means of the restriction endonuclease ecori. the circular arrangement of the more than 60 fragments generated by this enzyme was established by electrophoretic analysis of pbr322 clones harboring overlapping segments of pri1855 derived by partial digestion with ecori. a large region of the plasmid comprising the t-dna was mapped with two additional enzymes, bamhi and hindiii, by means of southern blot hybr ... | 1983 | 6314408 |
| extra dna in the t region of crown gall ti-plasmid ptia66. | the mutant tumorigenic phenotype of ptia66, a derivative of the broad host range octopine ti-plasmid ptia6, results from a 2.6-kb insertion into ecori fragment 32g of the t region, which has been implicated in the auxin synthesis disruption tumor character. the inserted dna is closely related to sequences from bamhi fragment 11 of the same or a related plasmid but probably originally derives from a chromosomal sequence. | 1983 | 6314413 |
| genetic aspects of biodegradation by pseudomonads. | | 1983 | 6315474 |
| sym plasmid transfer to various symbiotic mutants of rhizobium trifolii, r. leguminosarum, and r. meliloti. | two self-transmissible sym(biosis) plasmids, one encoding pea-specific nodulation and nitrogen-fixation functions (plasmid pjb5ji) and the other encoding clover-specific nodulation and nitrogen-fixation functions (plasmid pbr1an) were used to determine whether the symbiotic genes encoded on these plasmids are expressed in various members of the rhizobiaceae. the host specificity of rhizobium trifolii and r. leguminosarum sym plasmid-cured strains could be directly determined by the transfer to t ... | 1983 | 6315675 |
| regulation of hydrogenase in rhizobium japonicum: analysis of mutants altered in regulation by carbon substrates and oxygen. | the synthesis of the h2 uptake system in free-living rhizobium japonicum sr is repressed both by oxygen and by carbon substrates. mutants selected for the ability to express hydrogenase in 10.0% partial pressure o2 were also less sensitive than the wild type to repression by carbon substrates such as arabinose, glycerol, gluconate, and succinate. the h2 uptake system in another class of mutants, previously shown to be hypersensitive to repression by o2, is also more sensitive to repression by ca ... | 1983 | 6315681 |
| suicide plasmid vehicles for insertion mutagenesis in rhizobium meliloti and related bacteria. | we describe the construction and use of a set of plasmid vectors of the transposons tn1, tn5, and tn9 that are suicidal in rhizobium species and therefore suitable for mutagenesis with these three transposons. the vectors are composed of the p15a replicon which functions in escherichia coli but not in rhizobium species and a region encoding the n type of bacterial conjugation system which is very efficient in matings between e. coli and rhizobium species. the usefulness of the vectors has been m ... | 1983 | 6315684 |
| structural relationships among rhizobium meliloti symbiotic promoters. | symbiotic nitrogen fixation by rhizobium meliloti requires the developmentally specific expression of certain bacterial genes. one set of these genes encodes the subunits of nitrogenase, the enzyme responsible for the reduction of atmospheric dinitrogen to ammonia, and another set consists of closely linked genes also essential for nitrogen fixation. examination of promoter and probable regulatory regions for these gene sets has revealed extensive dna sequence conservation for more than 160 bp u ... | 1983 | 6317191 |
| genetic complementation of agrobacterium tumefaciens ti plasmid mutants in the virulence region. | mutants with tn5 insertions in the vir region of the agrobacterium tumefaciens tic58 plasmid are unable to form crown-gall tumors. complementation tests of these vir region mutants were carried out by constructing merodiploids in a recombination-deficient strain. each merodiploid possessed a mutant tic58 plasmid and a recombinant plasmid containing either the homologous wild-type dna region or the homologous region containing a second tn5 insertion. the analysis identified six complementation gr ... | 1984 | 6318043 |
| succinamopine: a new crown gall opine. | agrobacterium tumefaciens strains can incite plant tumors consisting of transformed cells that synthesize novel metabolites called opines. the pattern of opine synthesis is dictated by plasmid-borne genes in the pathogen; additional plasmid genes confer on the pathogen the ability to catabolize the same pattern of opines synthesized. one group of a. tumefaciens strains, at181, eu6, and t10/73, contains closely related tumor-inducing (ti) plasmids that encode the ability to degrade the opine nopa ... | 1984 | 6319354 |
| conservation of dna regions adjacent to nifkdh homologous sequences in diverse slow-growing rhizobium strains. | restriction endonuclease-digested deoxyribonucleic acid (dna) from 17 slow-growing rhizobium strains was hybridized with 32p-labeled dna of the klebsiella pneumoniae nitrogenase structural gene (nifkdh) region. sixteen of these strains contained two or more fragments that were homologous to k. pneumoniae nifkdh after cleavage with ecori or hindiii. hybridization with nifkdh subclones revealed that most of the rhizobium fragments were homologous to the hindiii-ecori portion of nifkdh (correspondi ... | 1983 | 6319524 |
| [cloning and the expression of the r. meliloti nitrogenase gene (nif d) in e. coli]. | | 1983 | 6321122 |
| [cloning of the ti-plasmid dna fragments of agrobacterium tumefaciens in escherichia coli and the identification of the site of origin of ti-plasmid replication]. | | 1983 | 6321123 |
| characterization of the replication and stability regions of agrobacterium tumefaciens plasmid ptar. | a 5.4-kilobase region containing the origin of replication and stability maintenance of the 44-kilobase agrobacterium tumefaciens plasmid ptar has been mapped and characterized. within this region is a 1.3-kilobase segment that is capable of directing autonomous replication. the remaining segment contains the stability locus for maintenance of ptar during nonselective growth. approximately 35% of ptar shares sequence homology with pag119, a 44-kilobase cryptic plasmid in grapevine strain 1d1119. ... | 1984 | 6321432 |
| generation of a tn5 promoter probe and its use in the study of gene expression in caulobacter crescentus. | a promoter probe, tn5-vb32, was constructed and placed in a p group r plasmid containing bacteriophage mu sequences, allowing transfer of the transposon to bacteria such as caulobacter, rhizobium, and agrobacterium without retention of the plasmid. the probe carries an altered tn5 transposon that allows detection of chromosomal promoter regions by virtue of acquired kanamycin resistance. a fragment of dna containing the neomycin phosphotransferase ii (npt ii) gene from tn5, lacking its promoter ... | 1984 | 6322183 |
| studies on tn951 (lac+) expression in agrobacterium. | none of the agrobacterium tumefaciens and a. rubi strains tested produces detectable amounts of beta-galactosidase although they are capable of utilizing lactose as sole source of carbon. this opportunity was taken to investigate the expression of lac transposon tn951 (cornelis et al. 1978) in agrobacterium with the ultimate goal of using this system to investigate alien gene expression. when the transposon was introduced with the help of a broad-host range plasmid, rp1, the transconjugants prod ... | 1984 | 6323925 |
| dna sequence analysis of crown gall tumor t-dna encoding the 0.7 kb transcript. | crown gall tumor formation involves integration into the plant genome of dna sequences (the t-region) of tumor-inducing (ti) plasmids present in agrobacterium tumefaciens. the t-dna of the tumor expresses several gene products. little is known about the function or regulation of expression of the 0.7kb transcript, which represents a relatively abundant t-dna transcript in octopine-type tumors. in this report, a detailed structural analysis of the gene encoding the 0.7 kb transcript has been obta ... | 1984 | 6324113 |
| physical map of the agrobacterium rhizogenes strain 8196 virulence plasmid. | virulence of agrobacterium rhizogenes, agent of hairy root disease, is conferred by large plasmids called ri (root-inducing) plasmids. we have determined the bamhi fragment map of pri8196, mw 143 mda, principally by analysis of recombinant plasmids containing overlapping bamhi partial-digest fragments. clones containing solitary bamhi inserts of remaining unmapped fragments were used to probe a series of southern-blotted, pri8196-derived ecori, psti, hindiii, sali, or smai digests. continguous h ... | 1984 | 6324259 |
| [genetic manipulation of plant cells]. | | 1983 | 6324283 |
| rhizobium phaseoli symbiotic mutants with transposon tn5 insertions. | rhizobium phaseoli cfn42 dna was mutated by random insertion of tn5 from suicide plasmid pjb4ji to obtain independently arising strains that were defective in symbiosis with phaseolus vulgaris but grew normally outside the plant. when these mutants were incubated with the plant, one did not initiate visible nodule tissue (nod-), seven led to slow nodule development (ndv), and two led to superficially normal early nodule development but lacked symbiotic nitrogenase activity (sna-). the nod- mutan ... | 1984 | 6325385 |
| the complete nucleotide sequence of the tl-dna of the agrobacterium tumefaciens plasmid ptiach5. | we have determined the complete primary structure (13 637 bp) of the tl-region of agrobacterium tumefaciens octopine plasmid ptiach5 . this sequence comprises two small direct repeats which flank the tl-region at each extremity and are involved in the transfer and/or integration of this dna segment in plants. tl-dna specifies eight open-reading frames corresponding to experimentally identified transcripts in crown gall tumor tissue. the eight coding regions are not interrupted by intervening seq ... | 1984 | 6327292 |
| transposon tn5 specifies streptomycin resistance in rhizobium spp. | transposon tn5 conferred streptomycin resistance on different strains of rhizobium meliloti, rhizobium leguminosarum, and rhizobium trifolii but not on escherichia coli. a gene (str) specifying this phenotype has been identified and localized on the physical and genetic map of tn5. it is transcribed from the promoter of neo, the gene that encodes neomycin phosphotransferase. the str gene is downstream from neo in a single transcriptional unit, as revealed by molecular cloning of different segmen ... | 1984 | 6327612 |
| identification of a rhizosphere protein encoded by the symbiotic plasmid of rhizobium leguminosarum. | a protein was identified which was made by wild-type strains of rhizobium leguminosarum but not by nodulation-deficient derivatives which had deletions of their symbiotic plasmids. the protein, which had a subunit molecular weight of ca. 24,000 ( 24k ), was found to be present in large amounts within bacteria that had been reisolated from the surface of inoculated pea roots but was not detected in bacteroids isolated from nodules. the protein could also be induced during growth of r. leguminosar ... | 1984 | 6327615 |
| rhizobium japonicum nitrogenase fe protein gene (nifh). | a 12.1-kilobase psti fragment from rhizobium japonicum, which contains homology to both the klebsiella pneumoniae and the rhizobium meliloti nifh genes, was cloned into vector phe3 . the nifh -homologous region was localized on the restriction enzyme cleavage map by southern blot hybridization experiments. dna fragments overlapping the r. japonicum nifh gene were subcloned into plasmid vectors to allow the expression of this region in escherichia coli minicells. the nifh gene product (the polype ... | 1984 | 6327620 |
| gene fusion vehicles for the analysis of gene expression in rhizobium meliloti. | a set of plasmid cloning vehicles was developed to facilitate the construction of gene or operon fusions in rhizobium meliloti. the vehicles also contain a broad-host-range replicon and could be introduced into bacteria either by transformation or by transduction, using bacteriophage p2. insertion of foreign dna into a unique restriction endonuclease cleavage site promotes the synthesis of either the escherichia coli lactose operon or the kanamycin phosphotransferase gene from transposon tn5. ex ... | 1984 | 6327625 |
| rhizobium meliloti nodulation genes allow agrobacterium tumefaciens and escherichia coli to form pseudonodules on alfalfa. | regions of the rhizobium meliloti symbiotic plasmid (20 to 40 kilobase pairs long) containing nodulation (nod) genes were transferred to agrobacterium tumefaciens or escherichia coli by conjugation. the a. tumefaciens and e. coli transconjugants elicited root hair curling and the formation of ineffective pseudonodules on inoculated alfalfa plants. a tumefaciens elicited pseudonodules formed at a variable frequency, ranging from 15 to 45%, irrespective of the presence of the ti plasmid. these pse ... | 1984 | 6327629 |
| isolation and expression of rhizobium japonicum cloned dna encoding an early soybean nodulation function. | a first visible step in the nodulation of legumes by rhizobium spp. is the deformation and curling of root hairs. we have identified and cloned dna sequences encoding this function from two strains of rhizobium japonicum (usda 122 and usda 110) with a weakly homologous probe from rhizobium meliloti. root hair curling encoded by the cloned dna fragments was examined on soybeans (glycine soja ) after conjugative transfer of these sequences in broad-host-range vectors to various bacterial genera. p ... | 1984 | 6327649 |
| t-dna fragments of hairy root plasmid pri8196 are distantly related to octopine and nopaline ti plasmid t-dna. | agrobacterium ti (tumor-inducing) and ri (root-inducing) plasmids transform dicot plant cells by insertion of a specific plasmid sector called t-dna (transferred dna) into host plant nuclear dna. the mannopine -type ri plasmid pri8196 contains four bamhi fragments that encompass core t-dna. we report southern hybridization studies that show that these four fragments have no strong homology to octopine-, nopaline-, or agropine -type ti plasmids. we detected and mapped very weak homology regions, ... | 1984 | 6328555 |
| a simple method to transfer, integrate and study expression of foreign genes, such as chicken ovalbumin and alpha-actin in plant tumors. | a simple method for inserting foreign genes into the t-region of agrobacterium ti-plasmids is described. a modified cosmid (phc 79) was introduced into a predetermined site of the t-region of pti c58. an agrobacterium strain harboring this modified ti-plasmid was used as an acceptor strain into which genes, cloned in pbr322, can be introduced by mobilization from escherichia coli. pbr322-derived plasmids cannot replicate in agrobacterium, but can be maintained by integration into the t-region of ... | 1984 | 6329731 |
| characterization of transposon tn5-facilitated donor strains and development of a chromosomal linkage map for agrobacterium tumefaciens. | we have further characterized the transposon tn5-facilitated chromosomal gene transfer system developed for agrobacterium tumefaciens 15955. using a strain whose chromosome contained tn5, we compared the chromosome-mobilizing ability of plasmid pdp37 (containing tn5) with that of its parent plasmid r68.45. for r68.45, we observed nonpolar transmission from multiple origins. for pdp37 we found polarized transmission from a single origin near ilv. when we examined the transmission gradients of a n ... | 1984 | 6330023 |
| general transduction in rhizobium meliloti. | general transduction by phage phi m12 in rhizobium meliloti su47 and its derivatives is described. cotransduction and selection for tn5 insertions which are closely linked to specific loci were demonstrated. a derivative of su47 carrying the reca::tn5 allele of r. meliloti 102f34 could be transduced for plasmid r68.45 but not for chromosomally located alleles. phage phi m12 is morphologically similar to escherichia coli phage t4, and restriction endonuclease analysis indicated that the phage dna ... | 1984 | 6330024 |
| generalized transduction in rhizobium meliloti. | generalized transduction of rhizobium meliloti 1021 was carried out by bacteriophage n3. genetic markers on the chromosome and the psym megaplasmid were transduced, along with markers on several incp plasmids. cotransduction between transposon tn5 insertions and integrated recombinant plasmid markers permitted correlation of cotransductional frequencies and known physical distances. bacteriophage n3 was capable of infecting several commonly used strains of r. meliloti. | 1984 | 6330025 |
| transposon tn5-induced mutagenesis of rhizobium japonicum yielding a wide variety of mutants. | when the "suicide" vector psup1011, which carries transposon tn5 (kmr), was introduced into rhizobium japonicum usda 110, kanamycin-resistant (kmr) colonies were detected at a frequency (4.2 x 10-6) ca. 30 times greater than the spontaneous kanamycin resistance frequency (1.4 x 10-7). ten thousand kmr mutants were isolated and tested for nutritional auxotrophy. auxotrophs were detected at a frequency of 0.5%. the following classes of auxotrophs were identified: adenine- (three), histidine- (thre ... | 1984 | 6330038 |
| transposon tn5 encodes streptomycin resistance in nonenteric bacteria. | strains of caulobacter crescentus, pseudomonas putida, acinetobacter calcoaceticus, rhizobium meliloti, and rhodopseudomonas sphaeroides carrying the kanamycin resistance-encoding transposon tn5 were 15 to 500 times more resistant to streptomycin than transposon-free strains. the streptomycin resistance determinant, which is separable from the kanamycin resistance determinant of tn5, was not expressed in escherichia coli or klebsiella aerogenes. | 1984 | 6330041 |
| host-dependent transposon tn5-mediated streptomycin resistance. | transposon tn5 encodes streptomycin resistance in addition to kanamycin-neomycin resistance. this resistance was not detectable in escherichia coli but was efficiently expressed in rhizobium meliloti and certain other strains. by analysis of cloned tn5 restriction endonuclease fragments, the streptomycin resistance (str) gene was located in the right-hand side of the central region as the transposon is conventionally drawn. transcription of str appeared to originate at pl, the promoter for the n ... | 1984 | 6330042 |
| nucleotide sequence and transcript mapping of the tmr gene of the ptia6nc octopine ti-plasmid: a bacterial gene involved in plant tumorigenesis. | the nucleotide sequence of a tumor morphology gene, tmr, from the agrobacterium tumefaciens ti-plasmid, ptia6nc, and its flanking 5' region was determined by m13 "dideoxy" procedures. the dna sequence reveals an open reading frame capable of encoding a 240 amino acid protein. we have identified the polyadenylated transcript initiation and termination sits by s1 nuclease mapping. the extent of the sequence required for transcription 5' to the start of transcription has been delimited by two trans ... | 1984 | 6330262 |
| molecular cloning and functional characterization of rhizobium leguminosarum structural nif-genes by site-directed transposon mutagenesis and expression in escherichia coli minicells. | in order to study the structural organization and regulation of the expression of the nitrogenase gene cluster in rhizobium leguminosarum pre we selected relevant subfragments of the sym-plasmid from clone banks by homology with r. meliloti nif-genes. site-directed tn5 mutagenesis was applied to a nif dh-specific clone and subsequently the transposon insertions were transferred back into the wild-type rhizobial genome by homologous recombination. phenotypic effects of tn5 mutations in the region ... | 1984 | 6330264 |
| light-inducible and chloroplast-associated expression of a chimaeric gene introduced into nicotiana tabacum using a ti plasmid vector. | a chimaeric gene, consisting of the 5'-flanking region of a member of the pisum sativum gene family encoding ribulose 1,5-bisphosphate carboxylase linked to the coding region of a bacterial chloramphenicol acetyltransferase gene, has been introduced into the genome of the plant nicotiana tabacum using a ti plasmid of agrobacterium tumefaciens. the expression of the chimaeric gene is light-inducible in chloroplast-containing transformed tissue. | 1984 | 6330570 |
| nucleotide sequence of the tmr locus of agrobacterium tumefaciens pti t37 t-dna. | the nucleotide sequence of the tmr locus from the nopaline-type pti t37 plasmid of agrobacterium tumefaciens was determined. examination of this sequence allowed us to identify an open reading frame of 720 nucleotides capable of encoding a protein with a derived molecular weight of 27025 d. comparison of the pti t37 tmr sequence with the published sequence of the pti ach5 tmr locus shows over 88% homology in the 240 bases 5' to the translational initiation codon and over 91% homology in the codi ... | 1984 | 6330678 |
| nucleotide sequence of rhizobium meliloti nodulation genes. | a rhizobium meliloti dna region, determining nodulation functions common in different rhizobium species, has been delimited by directed tn5 mutagenesis and its nucleotide sequence has been determined. the sequence data indicates three large open reading frames with the same polarity coding for three proteins of 196, 217 and 402 (or 426) amino acid residues, respectively. we suggest the existence of three nod genes on this region, which were designated as noda, b and c, respectively. comparison o ... | 1984 | 6336331 |
| klebsiella pneumoniae nifa product activates the rhizobium meliloti nitrogenase promoter. | bacteria in the genus rhizobium normally fix nitrogen only when they interact with leguminous plants to produce on the roots a highly differentiated structure, the nodule, within which the bacteria differentiate into nitrogen-fixing bacteroids. by contrast, the enteric bacterium klebsiella pneumoniae reduces nitrogen in a free-living state in conditions of low oxygen tension and deficiency of fixed nitrogen. in k. pneumoniae, the overall circuitry by which nitrogen-fixation (nif) genes are regul ... | 1983 | 6338395 |
| rhizobium infection and nodulation: a beneficial plant disease? | | 1983 | 6357057 |
| detoxification of pesticides by microbial enzymes. | | 1983 | 6357841 |
| induced plasmid-genome rearrangements in rhizobium japonicum. | the p group resistance plasmids rp1 and rp4 were introduced into rhizobium japonicum by polyethylene-glycol-induced transformation of spheroplasts. after cell wall regeneration, transformants were recovered by selecting for plasmid determinants. plant nodulation, nitrogen fixation, serological, and bacterial genetics studies revealed that the transformants were derived from the parental strains and possessed the introduced plasmid genetic markers. agarose gel electrophoresis, restriction enzyme ... | 1984 | 6360996 |
| physical and genetic characterization of rhizobium meliloti symbiotic mutants. | a set of 19 symbiotic mutants of rhizobium meliloti obtained by a tn5 "suicide plasmid" mutagenesis procedure was characterized genetically and physically. as part of this characterization, we showed that r. meliloti strain 1021, like other r. meliloti strains, contains a very large indigenous plasmid (greater than 300 md) that carries the structural genes for nitrogenase (nifhdk genes). among the 19 symbiotic mutations studied, at least six were shown to reside on the megaplasmid. by a "walking ... | 1983 | 6363587 |
| the t-region of ti plasmids codes for an enzyme synthesizing indole-3-acetic acid. | gene 2 from the t region of ti plasmids appears to be expressed both in eucaryotic and in procaryotic systems. in transformed plant cells it participates in auxin-controlled growth and differentiation, and in bacteria it is expressed into a defined protein of mr 49000. we investigated the possibility that it codes for an enzyme involved in auxin biosynthesis. only extracts from escherichia coli cells expressing gene 2 hydrolyzed indole-3-acetamide into a substance which was unambiguously identif ... | 1984 | 6365544 |
| the sequence of the tms transcript 2 locus of the a. tumefaciens plasmid ptia6 and characterization of the mutation in ptia66 that is responsible for auxin attenuation. | the incorporation of ti plasmid sequences, the t-dna, into the genomes of dicotyledenous plants causes the formation of tumors. here we report the nucleotide sequence of one of the t-dna "oncogenes", the transcript 2 gene of ptia6 and we further characterize the 2.7 kb element that has spontaneously inserted into this gene in plasmid ptia66. the results indicate that the transcript 2 portion of the t-dna has an open reading frame that could encode a polypeptide of 49.8 kd. the open reading frame ... | 1984 | 6366736 |
| parasitic origins of nitrogen-mixing rhizobium-legume symbioses. a review of the evidence. | this paper is divided into two sections. the first part (i) reviews the literature on the legume-rhizobium association with emphasis on the processes leading to the establishment of the association. in the second part (ii) it is proposed that the legume-rhizobium association was originally necrotrophic , beginning when the free-living, nitrogen-fixing, saprotrophic rhizobium developed the ability to infect the plant. the pre-infection events, infection processes and nodulation in the colonizatio ... | 1983 | 6370330 |
| regulation of nitrogen fixation genes. | | 1984 | 6373013 |
| trans-acting virulence functions of the octopine ti plasmid from agrobacterium tumefaciens. | all ti plasmid-encoded virulence functions that were studied act in trans. an octopine ti plasmid-specific vir operon, called vir-o, located on an ecori restriction fragment has been characterized. sequences with promoter activity in escherichia coli were identified for a second vir operon, called vir-c, which was located close to the position of vir-o. | 1984 | 6373732 |
| thioredoxin system of the photosynthetic anaerobe chromatium vinosum. | chromatium vinosum, an anaerobic photosynthetic purple sulfur bacterium, resembles aerobic bacterial cells in that it has an nadp-thioredoxin system composed of a single thioredoxin which is reduced by nadph via nadp-thioredoxin reductase. both protein components were purified to homogeneity, and some of their properties were determined. chromatium vinosum thioredoxin was slightly larger than other bacterial thioredoxins (13 versus 12 kilodaltons) but was similar in its specificity (ability to a ... | 1984 | 6373736 |
| changes in properties of phytopathogenic bacteria effected by plasmid prd1. | transfer of plasmid prd1 from escherichia coli k 12j62 -1 to phytopathogenic bacteria, agrobacterium tumefaciens, xanthomonas beticola and erwinia carotovora subsp. carotovora caused changes in conjugant properties not determined by the plasmid and the emergence of the properties not present in the parent strains. clones have been obtained with intermediate properties between donor and recipient, including those with altered or lost virulence. in transconjugants of a. tumefaciens virulence incre ... | 1984 | 6375619 |