| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| [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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| monoclonal antibodies specific for escherichia coli j5 lipopolysaccharide: cross-reaction with other gram-negative bacterial species. | four monoclonal antibodies against escherichia coli j5 were studied. each of these monoclonal antibodies reacted with purified lipopolysaccharides from e. coli j5, the deep rough mutant salmonella minnesota re595, agrobacterium tumefaciens, and pseudomonas aeruginosa pao1 as well as with the purified lipid a of p. aeruginosa. enzyme-linked immunosorbent assays using the outer membranes from a variety of gram-negative bacteria demonstrated that these lipid a-specific monoclonal antibodies interac ... | 1984 | 6381310 |
| [degradation and utilization of 2,4-dioxohexahydro-1,3,5-triazine (dht) by soil microorganisms]. | the biodegradation and utilization of the antiphytoviral substance 2,4-dioxohexahydro-1,3,5-triazine (dht) by soil microorganisms was investigated. mixed cultures of microorganisms deriving from different soils diminish in nutrient broth the content of dht with increasing duration of culture. microorganisms from an egyptian garden soil fully degrade 10(-3) mol/1 dht in a culture without additional aeration within 28 days. also in deficient media the mixed microorganisms reduce the amount of dht, ... | 1984 | 6388190 |
| comparative study of the dna-binding hu-type proteins from slow growing and fast growing strains of rhizobiaceae. | the dna-binding hu-type proteins have been isolated from two very different strains of rhizobiaceae : agrobacterium tumefaciens and rhizobium japonicum. these proteins have been called hat and hrj respectively. their electrophoretic mobility on polyacrylamide gel, amino acid composition and crossed immunoreactivity have been compared to that of the homologous protein isolated from rhizobium meliloti: the protein hrm . the proteins hat and hrm show close similarities whereas the protein hrj diffe ... | 1984 | 6428409 |
| nature and location of amide-bound (r)-3-acyloxyacyl groups in lipid a of lipopolysaccharides from various gram-negative bacteria. | it has previously been demonstrated [eur. j. biochem. 124, 191-198 (1982) and 137, 15-22 (1983)] that the lipid a component of salmonella and proteus lipopolysaccharides contains amide-linked (r)-3-acyloxyacyl residues. in the present study lipid a of other gram-negative bacteria was analysed for the presence of amide-bound 3-acyloxyacyl residues. it was found that such residues are constituents of all lipid a tested (agrobacterium tumefaciens, chromobacterium violaceum, pseudomonas aeruginosa, ... | 1984 | 6437812 |
| relationship of siderophore-mediated iron assimilation to virulence in crown gall disease. | three classes of mutants defective in the biosynthesis of the siderophore agrobactin were isolated from agrobacterium tumefaciens a217 after n-methyl-n'-nitro-n-nitrosoguanidine mutagenesis. class i mutants produced uniquely the catechol 2,3-dihydroxybenzoic acid, whereas classes ii and iii produced no detectable catechol. class ii differed from class iii mutants in that exogenous 2,3-dihydroxybenzoic acid was utilized only by the former to synthesize agrobactin. growth of strains b6 and a217, u ... | 1981 | 6455414 |
| structure and synthesis of histopine, a histidine derivative produced by crown gall tumors. | histopine, an unusual amino acid derivative of histidine isolated from crown gall tumors of sunflowers (helianthus annus) inoculated with agrobacterium tumefaciens strain b6, was previously assigned the gross structure n-(1-carboxyethyl) histidine (2). a diastereomeric mixture containing histopine (2a and 2b) was readily prepared by reductive alkylation of (s)-histidine (1) with pyruvic acid and sodium cyanoborohydride. the individual diastereomers were prepared by reaction of (s)-histidine with ... | 1984 | 6466642 |
| mapping of promoter-proximal regions by in vitro transcription of two agrobacterium tumefaciens ti-plasmids. | transcription initiation sites were mapped on both the octopine pti ach5 and the nopaline pti c58 plasmids of agrobacterium tumefaciens. transcription ternary complexes were subjected to electrophoresis on agarose gels, prior and/or subsequent to restriction endonuclease digestion of the dna template, evidenced by autoradiography and located on the restriction maps of the two tumor-inducing plasmids. a. tumefaciens rna polymerase promptly recognizes and starts transcription on a few sequences wh ... | 1984 | 6472259 |
| enhanced 3-methoxytyramine levels in crown gall tumours and other undifferentiated plant tissues. | an amine, after dansylation, has been isolated from nicotiana tabacum crown gall tumours for the first time and characterized as 4-hydroxy-3-methoxy-beta-phenylethylamine (3-methoxytyramine). the compound cannot be detected in differentiated n. tabacum tissues but appears in the corresponding callus controls. its concentration is further increased 5-42-fold when n. tabacum is transformed with all strains of agrobacterium tumefaciens so far tested. | 1984 | 6477503 |
| crown gall transformation of tobacco callus cells by cocultivation with agrobacterium tumefaciens. | incubation of cells from squashed tobacco callus tissue with virulent agrobacterium tumefaciens leads to the production of cells displaying a crown gall phenotype. | 1984 | 6487297 |
| phosphorylation of chromosomal proteins during the transition of a normal plant cell to a crown gall tumor cell. | the transition of a wounded plant cell to a crown gall tumor cell, which is induced by infection with virulent agrobacterium tumefaciens cells, is accompanied by enhancement of chromatin-bound protein phosphokinase activity. various protein kinases with different substrate specificity (viz. histone, phosvitin, casein phosphokinases) are distinctly more active in tumor cells. the phosphate is introduced into seryl and threonyl residues of proteins and is stable under standard assay conditions, th ... | 1984 | 6489456 |
| adsorption of tumorigenic agrobacterium tumefaciens cells to susceptible potato tuber tissues. | cells of tumorigenic agrobacterium tumefaciens strain b6 were labeled with [35s]methionine and used to estimate bacterial adsorption to potato tuber discs. after 10 min at ph 7.2, about 5 x 10(5) bacteria adsorb to each 9.0-mm disc. lengthening the incubation period to 90 min increases adsorption to about 11 x 10(5) bacteria per disc. bacterial adsorption is reduced under both alkaline and acid ph conditions and increases 2.3-fold if the number of bacterial cells in the inoculum is doubled. adso ... | 1984 | 6498639 |
| plant-inducible virulence promoter of the agrobacterium tumefaciens ti plasmid. | agrobacterium tumefaciens is the causative agent of crown gall, a plant tumour that can arise on most species of dicotyledonous plants. the tumour-inducing capacity of the bacterium requires the presence of a large plasmid, designated the ti plasmid, which itself contains two regions essential for tumour formation-the t(umour)-region and the vir(ulence)-region. the t-region is transferred to plant cells by an unknown mechanism, and becomes stably integrated into the plant genome. the vir-region ... | 1984 | 6504164 |
| detection of tumor-inducing plasmid dna sequence in agrobacterium tumefaciens by dna-dna hybridization. | absence of plasmid dna sequences in non-tumorigenic (crown gall tumor) strains of agrobacterium tumefaciens was confirmed by dna-dna hybridization between purified tumor-inducing (ti) plasmid dnas isolated from the progenitor tumorigenic strains and 3h-labeled whole cell dnas from tumorigenic strains and their non-tumorigenic derivatives. the genes controlling tumorigenicity in plant and utilizability of nopaline as their sole nitrogen source were confirmed to locate on ti-plasmids. | 1984 | 6505307 |
| antioxidant defence system of erythrocytes in relation to agrobacterium tumefaciens lipopolysaccharide administration in mice. | | 1984 | 6519684 |
| a functional map of the nopaline catabolism genes on the ti plasmid of agrobacterium tumefaciens c58. | the nopaline catabolism (noc) genes are located in a 14.4 kb region on the ptic58 plasmid of a. tumefaciens c58. these genes permit the bacterium to grow on nopaline n2-(1,3-dicarboxylpropyl) arginine, a substrate produced in plant tumors initiated by strain c58. the functions of the noc genes include the use of nopaline and l-ornithine as sole carbon and nitrogen sources. using tn5 insertional mutants, we have identified and mapped the positions of the genes that are responsible for nopaline ca ... | 1983 | 6577260 |
| a general method for the transfer of cloned genes to plant cells. | this paper describes a method for the transfer to plant cells of any cloned gene, regardless of its termini or internal restriction enzyme cleavage sites. a broad host-range intermediate vector, pgv1117, was constructed containing hindiii-23, a right-end t-region fragment of the nopaline plasmid ptic58. using in vivo protection by ecori methylase and ecori linker ligation, a fragment of rabbit chromosomal dna, carrying the beta-globin gene, was inserted into plasmid pgv1117. following transmissi ... | 1983 | 6628995 |
| presence of a new cytochrome b - like pigment with a peak at 567 nm in various aerobic bacteria. | several physiological groups of bacteria were examined for the presence of a cytochrome b - like pigment which is demonstrable in dithionite-reduced minus substrate-reduced difference spectra. this pigment is characterized by an unusually high alpha band at 567 nm, a low concentration relative to conventional cytochromes, and an inability to be fully reduced by endogenous substrates or nadh. previous studies with one denitrifying and nondenitrifying species of the genus pseudomonas, in paracoccu ... | 1983 | 6652580 |
| relationship between adenylate cytokinin production and ti plasmid of agrobacterium tumefaciens. | to know whether the tumor-inducing plasmid of agrobacterium tumefaciens carries genetic information of the biosynthesis of cytokinins, the levels of 6-(3-methyl-2-butenyl-amino)purine (ipade) and its 4-hydroxy derivative trans-zeatin (trans-z) and its p-beta-d-ribofuranoside (trans-zr) produced in media by wild-type virulent strain, plasmid-cured avirulent strain and the deletion mutant were compared. the highest levels of ipade and trans-z were found in the culture filtrate of late-log phase gr ... | 1983 | 6664842 |
| physical & chemical studies on lipopolysaccharide of agrobacterium tumefaciens. | | 1983 | 6671675 |
| transfer of rhizobium meliloti psym genes into agrobacterium tumefaciens: host-specific nodulation by atypical infection. | the psym megaplasmid of rhizobium meliloti 2011 mobilized by plasmid rp4, or plasmid pgmi42, an rp4-prime derivative which carries a 290-kilobase psym fragment including nitrogenase and nod genes, was introduced into agrobacterium tumefaciens. the resulting transconjugants induced root deformations specifically on the homologous hosts medicago sativa and melilotus alba and not on the heterologous hosts trifolium pratense and trifolium repens. the root deformations were shown to be genuine nodule ... | 1984 | 6690420 |
| hairy-root-inducing plasmid: physical map and homology to tumor-inducing plasmids. | a physical map was constructed for the 250-kilobase plasmid pria4b, which confers the virulence properties of a strain of agrobacterium rhizogenes for hairy root disease in plants. the complete hindiii and kpni restriction map was determined from a collection of overlapping hindiii partial digest clones. homologous regions with two well-characterized plasmids that confer virulence for crown gall disease, plasmids ptia6 and ptit37, were mapped on pria4b. as much as 160 kilobases of pria4b had det ... | 1984 | 6690423 |
| d-glucosaminate dehydratase: spectrometric properties of the enzyme-bound pyridoxal 5'-phosphate. | the holoenzyme of d-glucosaminate dehydratase [ec 4.2.1.26] from agrobacterium radiobacter showed absorption peaks at 280 and 415 nm with a shoulder in the region of 320 to 330 nm. the treatment of the enzyme with hydroxylamine followed by dialysis led to disappearance of both the absorption peak at 415 nm and the shoulder, giving the apoenzyme. the fluorescence excitation maximum of the holoenzyme was at 320 nm with a shoulder at 420 nm (emission at 510 nm), and the emission maxima were at 420 ... | 1984 | 6706902 |
| flagella-specific bacteriophages of agrobacterium tumefaciens: demonstration of virulence of nonmotile mutants. | bacteriophages gs2 and gs6 for agrobacterium tumefaciens were shown by electron microscopy to adsorb to flagella. this specificity was confirmed by the finding that phage-resistant mutants were nonmotile. such mutants retained tumor-inducing virulence and ability to attach to plant cells, indicating that motility was not required for these properties. both phages had contractile tails and appeared similar in the electron microscope. | 1984 | 6744126 |
| transcription of a zein gene introduced into sunflower using a ti plasmid vector. | a maize genomic clone containing a zein gene (z4) was inserted into the t-region of the t37 ti plasmid. agrobacterium tumefaciens cells carrying this modified ti plasmid were used to inoculate sunflower stemlets. callus tissue active in nopaline synthesis was grown from a single transformed cell. dna analysis of this tissue showed that the zein gene plus t-dna was present in approximately 12 copies per diploid sunflower genome. a 1000 +/- 100 base rna homologous to a zein probe could be isolated ... | 1984 | 6745240 |
| expression of ti-plasmid dna in e. coli: comparison of homologous fragments cloned from ti plasmids of agrobacterium strains c58 and ach5. | fragments of two ti plasmids from agrobacterium tumefaciens were cloned and studied for cross-hybridization. homologous fragments were further investigated for areas of strong homology and mapped with various restriction enzymes. the fragments were inserted in two directions and the recombinant plasmid was brought into e. coli strains producing minicells. about five proteins were found to be coded by those fragments of the ti plasmids. | 1980 | 6765583 |
| [preparation and properties of new catabolic substrates for two types of oncogenic plasmids of agrobacterium tumefaciens]. | reduction of the schiff bases formed between glucose, mannose or galactose with glutamic acid yields products related both structurally and biologically to agropine and to a derivative of agropine present in crown gall tumours. the catabolism of these compounds is coded for by octopine and agropine ti-plasmids of agrobacterium tumefaciens. | 1980 | 6772324 |
| occurrence of l-lysine epsilon-dehydrogenase in agrobacterium tumefaciens. | a novel amino acid dehydrogenase catalyzing the oxidative deamination of the epsilon-amino group of l-lysine was found in the crude extract of agrobacterium tumefaciens icr 1660. the enzyme required nad(+) and was specific for l-lysine. the enzyme was optimally active at about ph 9.7. | 1982 | 6801024 |
| biosynthesis of monobactam compounds: origin of the carbon atoms in the beta-lactam ring. | the biosynthesis of monobactams by strains of chromobacterium violaceum, acetobacter sp., and agrobacterium radiobacter was studied. monobactams were produced during logarithmic growth by c. violaceum and acetobacter sp. and during late log growth on glycerol and in stationary phase by a. radiobacter. the addition of various amino acids failed to significantly stimulate monobactam production in any of the producing organisms. several 14c-amino acids and pyruvate were incorporated in vivo into mo ... | 1982 | 6805424 |
| r68.45 mediated chromosomal gene transfer in agrobacterium tumefaciens. | a large plasmid enables its host agrobacterium tumefaciens to cause tumorous condition in a wide variety of dicotyledonous plants[see ooms et al. gene 14:33--50 (1981) )). the location and role of chromosomal genes in this phenomenon are not known. as the first stage in studying this aspect, a project was initiated to investigate the chromosomal genetics of the bacterium. r68.45, a p group plasmid, was chosen as a transmission agent. after a preliminary assessment it was decided to use c58 as a ... | 1982 | 6808964 |
| lytic effects of edta & lysozyme on virulent & avirulent strains of agrobacterium tumefaciens. | | 1982 | 6809600 |
| fate in model ecosystems of microbial species of potential use in genetic engineering. | the changes in populations of staphylococcus aureus, bacillus subtilis, salmonella typhimurium, klebsiella pneumoniae, agrobacterium tumefaciens, rhizobium meliloti, and saccharomyces cerevisiae were measured after their introduction into samples of sewage, lake water, and soil. enumeration of small populations was possible because the strains used were resistant to antibiotics in concentrations and combinations such that few species native to these ecosystems were able to grow on agar containin ... | 1982 | 6814361 |
| genetic analysis of t-dna transcripts in nopaline crown galls. | plant crown gall tumor cells result from the insertion and expression of a defined dna sequence, called t-dna, which is derived from the ti plasmid, harbored by agrobacterium tumefaciens strains. to study the function of the genes of the t-dna of the nopaline ti plasmid, ptic58, a collection of mutants was isolated so that t-dna genes are inactivated either separately or in various combinations. it was found that no single t-dna gene or t-region border is absolutely essential for stable tumor fo ... | 1983 | 6839358 |
| sulfur metabolism in the biosynthesis of monobactams. | we studied the biosynthesis of monobactams with respect to sulfur metabolism in chromobacterium violaceum, acetobacter sp., and agrobacterium radiobacter. all three organisms used inorganic sulfur for monobactam production. when sulfur-containing amino acids were assayed as a source of sulfur for monobactam production, c. violaceum used cystine but not cysteine or methionine, acetobacter sp. used all three compounds, and a. radiobacter used none. 35s from cysteine, methionine, and sodium sulfate ... | 1983 | 6859838 |
| morphology of root nodules and nodule-like structures formed by rhizobium and agrobacterium strains containing a rhizobium meliloti megaplasmid. | we examined expression of the megaplasmid prme41b of rhizobium meliloti in two different rhizobium sp. strains and in agrobacterium tumefaciens. transfer of prme41b into these bacteria was facilitated by insertion of a recombinant plasmid coding for mobilization functions of rp4 into the nif region (kondorosi, a., e. kondorosi, c.e. pankhurst, w. j. broughton, and z. banfalvi, 1982, mol. gen. genet., 188:433-439). in all cases, transconjugants formed nodule-like structures on the roots of medica ... | 1983 | 6885919 |
| plasmid dna of agrobacterium tumefaciens detected in a presumed habituated tobacco cell line. | 'tabac anergié' tissue has been used by many investigators as a habituated tobacco cell line. in this study, we have found sequences which are homologous to approximately 9 megadaltons of an agrobacterium octopine-type plasmid in dna isolated from 'tabac anergié' tissue. these t-dna sequences were shown to be the same 'core dna' sequences found to be present in several other unorganized tumor lines which have been studied in our laboratory. the t-dna was also shown to be integrated into plant dn ... | 1980 | 6935494 |
| mendelian transmission of genes introduced into plants by the ti plasmids of agrobacterium tumefaciens. | insertion of the bacterial transposon tn7 was used to obtain mutants of an octopine ti plasmid. crown gall tumours induced on tobacco by an agrobacterium tumefaciens strain carrying a particular mutant ti plasmid (pgv2100) were found to give rise to shoots. these shoots were grown in vitro and one of them (rgv-1) was found to contain the t-dna specific enzyme lysopine dehydrogenase (lpdh) and to form roots. after transfer to soil, rgv-1 developed into a morphologically and functionally normal to ... | 1981 | 6948997 |
| site-specific insertion of genes into t-dna of the agrobacterium tumor-inducing plasmid: an approach to genetic engineering of higher plant cells. | this paper presents a method for insertion of genetic material into a specific site in t-dna, the portion of agrobacterium tumor-inducing (ti) plasmid that becomes incorporated into the nuclear dna of transformed plant cells when crown gall tumors are incited by this plant pathogen. the three stages of our procedure are as follows: 1. a t-dna subfragment cloned in pbr322 is cleaved by a restriction endonuclease at a unique central site and target dna (a kanamycin resistance marker) is ligated in ... | 1981 | 6955419 |
| indoleacetic acid complementation and its relation to host range specifying genes on the ti plasmid of agrobacterium tumefaciens. | host range variations were noted when 23 wild-type strains of agrobacterium tumefaciens were tested on 27 different plant species. because we have shown previously that host range specificity is conferred by the pti plasmid, these variations in host specificity implicated genetic differences among pti plasmids within the a. tumefaciens population that was tested. host specificity was independent of the type of opine utilized and biotype of the strain used. these data suggested that separate gene ... | 1982 | 6962315 |
| em5400, a family of monobactam antibiotics produced by agrobacterium radiobacter. i. taxonomy, fermentation and biological properties. | | 1982 | 6978878 |
| antimicrobial, insect sterilizing and ovicidal activity of some oxo-vanadium(iv) and oxo-vanadium(v) complexes. | twenty-three newly synthesized mixed-ligand complexes of oxo-vanadium(iv) and oxo-vanadium(v) were studied for antimicrobial activity. eight of these complexes were found to have microbicidal properties. the complexes [nh4][vo(gl)2]h2o (gl-h2 = glycolic acid) and [vo(acoap)(acac-h)]h20 (acoap-h2=schiff base of acetylacetone and orthoaminophenol, acac-h=acetyl-acetone) show broad bactericidal spectra, while the complexes [vo(acsam)2]oh (acsam-h = schiff base of acetylacetone and sulphanilamide) ... | 1982 | 6983826 |
| evolutionary relationship between halobacterium cutirubrum and eukaryotes determined by use of aminoacyl-trna synthetases as phylogenetic probes. | the cross-species reactivities between trnas and aminoacyl-trna synthetases have been employed as a basis to estimate the relatedness of various prokaryotes to the eukaryotes. the trna of halobacterium cutirubrum, unlike that of other prokaryotes tested, including agrobacterium tumefaciens, arthrobacter luteus, bacillus subtilis, bacillus stearothermophilus, escherichia coli, micrococcus luteus, myxococcus xanthus, rhodopseudomonas spheroides, and thermus aquaticus, was found to share with yeast ... | 1980 | 6989454 |
| a coupled transcription-translation system from agrobacterium tumefaciens and its application to study ti plasmid expression in vitro. | a coupled transcription-translation system was isolated from a. tumefaciens. expression of plasmids pbr322 and pkt212 from e.coli, cloned fragments of ti plasmid (plasmids pss155 and pss156) and ti plasmid derivatives pal2802, pal2811, pal2821 and pal2832 was analysed in an a. tumefaciens cell-free system and compared with their expression in an e.coli cell-free system. new proteins of 41k and 44k appeared in a tumefaciens extracts, as the result of ti plasmid expression. these proteins were not ... | 1981 | 7038628 |
| ferrisiderophore reductase activity in agrobacterium tumefaciens. | reduction of the iron in ferriagrobactin by the cytoplasmic fraction of agrobacterium tumefaciens strictly required nadh as the reductant. addition of flavin mononucleotide and anaerobic conditions were necessary for the reaction; when added with flavin mononucleotide, magnesium was stimulatory. this ferrisiderophore reductase activity may be a part of the iron assimilation process in a. tumefaciens. | 1982 | 7056702 |
| relationship between nif plasmids of fast-growing rhizobium species and ti plasmids of agrobacterium tumefaciens. | by use of the southern blot hybridization technique the extent of dna homology was determined between the nif plasmid of a number of fast-growing rhizobium species and ti plasmids of the octopine (ptiach5) and nopaline (ptic58) type. dna sequences common to these plasmids were located on functional maps of the ti plasmids. no homology between nif plasmids and the t region of ti plasmids was detected. | 1982 | 7061382 |
| complementation analysis of agrobacterium tumefaciens ti plasmid mutations affecting oncogenicity. | a wide host range cosmid vector has been constructed by insertion of the lambda cos site into the plasmid prk2501. this cosmid, which is maintained in agrobacterium tumefaciens and is compatible with the ti plasmid, has been used to make a clone bank of the a. tumefaciens ptia6 plasmid. several ptia6 cosmids have been used to complement tn5-induced ti plasmid mutations. five avirulent mutations which map outside of the region of the plasmid maintained in plant tumours (t-dna) could be complement ... | 1982 | 7061395 |
| d-glucosaminate dehydratase from agrobacterium radiobacter. physicochemical and enzymological properties. | the bacterial distribution of d-glucosaminate dehydratase [ec 4.2.1.26] was investigated and agrobacterium radiobacter (iam 1526) was found to have the highest enzyme activity. the enzyme was formed inducibly in a glycerol-urea medium by d-glucosamine, d-galactosamine, and d-glucosamine, but not by d-mannosamine. the enzyme purified from the cells grown in the glucosamine-glycerol-urea medium was shown to be homogeneous by ultracentrifugation. the molecular weight was determined to be about 66,0 ... | 1982 | 7068563 |
| [physiological and biochemical characteristics of the cells of a carrot gall tumor developing in weightlessness]. | the paper presents the results of experiments with the carrot tissues infected with agrobacterium tumefaciens flown onboard the biosatellite cosmos-1129 in cooperation with the us scientists. postflight, the respiratory activity of tumour cells was determined and k+ and na+ permeability of cell membranes was measured. the resulting data give evidence that in weightlessness the development of the carrot gall tumour is accompanied by changes in the above physiological and biochemical parameters. t ... | 1982 | 7070038 |
| secretion of trans-zeatin by agrobacterium tumefaciens: a function determined by the nopaline ti plasmid. | | 1982 | 7073755 |
| em5400, a family of monobactam antibiotics produced by agrobacterium radiobacter. ii. isolation and structure determination. | | 1982 | 7076578 |
| characteristics of ti plasmids from broad-host-range and ecologically specific biotype 2 and 3 strains of agrobacterium tumefaciens. | agrobacterium tumefaciens strains isolated from crown gall tumors on grapevines in california were consistently of the biotype 3 group. all 11 of these strains were limited in their host range and harbored ti plasmids with molecular masses between 119 and 142 megadaltons (mdal) as well as a larger cryptic plasmid of greater than 200 mdal; occasionally a smaller cryptic plasmid of 65 mdal was also present. ti plasmids o these strains have dna sequences in common with ti plasmids of octopine and n ... | 1982 | 7085561 |
| regions of homology between tumorigenic plasmids from agrobacterium rhizogenes and agrobacterium tumefaciens. | | 1982 | 7089090 |
| tumor induction by agrobacterium tumefaciens: analysis of the boundaries of t-dna. | molecular cloning has been used to isolate the ends of that portion of the tumor-inducing (ti) plasmid of agrobacterium tumefaciens which has been designated t-dna and which has been transferred to the genome of tobacco crown gall tumor cells. analysis of the dna sequences of the plant border clones compared with the corresponding sequences of the ti plasmid suggests that the mechanism of transferred dna integration and subsequent stabilization is precise at the right border and imprecise on the ... | 1982 | 7108407 |
| passage of bacterial dna into host cells during in vitro transformation of nicotiana tabacum by agrobacterium tumefaciens. | tumorigenic and non-tumorigenic strains of agrobacterium tumefaciens were labelled with tritiated thymidine and added separately to suspension cultures of x-d line habituated tobacco cells. the subsequent association of bacteria with plant host cells and the passage of bacteria and bacterial dna into these cells was examined by conventional light and electron microscopy and light microscope autoradiography. the results suggest that both strains of bacterium enter damaged host cells (via wall les ... | 1982 | 7144594 |
| identification of the sym plasmid of rhizobium leguminosarum strain 1001 and its transfer to and expression in other rhizobia and agrobacterium tumefaciens. | | 1982 | 7146147 |
| dna from the a6s/2 crown gall tumor contains scrambled ti-plasmid sequences near its junctions with plant dna. | the a6s/2 tumor incited on tobacco by agrobacterium tumefaciens harboring the octopine-type a6 ti plasmid contains one insert of ti-plasmid sequences (the t dna). this 13 kb insert is derived from a colinear sequence in the ti plasmid (the t region) and becomes attached to plant dna in the nucleus of the host cell. we have determined the dna sequence encompassing the left end of the t region of the a6 ti plasmid and the corresponding portion of the a6s/2 t dna. the two sequences are identical fo ... | 1982 | 7151163 |
| nucleotide sequence and transcript map of the agrobacterium tumefaciens ti plasmid-encoded octopine synthase gene. | we have determined the complete nucleotide sequence of the gene for the crown gall enzyme, octopine synthase. the sequence was derived from cloned fragments of the agrobacterium tumefaciens ti plasmid ach5. it displayed a continuous open reading frame encoding a polypeptide chain of 358 amino acids. the nucleotide positions corresponding to the 5' end and poly(a) addition site of the mature octopine synthase mrna from a tobacco tumor cell line were determined by s1 nuclease mapping. two sequence ... | 1982 | 7153687 |
| nopaline synthase: transcript mapping and dna sequence. | the dna sequence of the nopaline synthase gene (nos) from agrobacterium tumefaciens ti plasmid ptit37 and adjacent regions up to the right border of the t-dna was determined. the 5' and 3' termini of the polyadenylated nos mrna, isolated from a t37 tobacco teratoma tumor line, were localized by s1 mapping. the final mrna is unspliced, encoded by a region of about 1450 bp, and specifies an open reading frame of 413 amino acids. potential transcriptional signals in the 5' flanking dna, such as cat ... | 1982 | 7153689 |
| modification and evaluation of the potato disc assay and antitumor screening of euphorbiaceae seeds. | galsky et al. (10, 11) have reported that the inhibition and growth of crown gall tumors, initiated on potato discs by agrobacterium tumefaciens, apparently has good agreement with 3ps in vivo antileukemic activity in mice. we have now modified and evaluated this assay for its potential use as a prescreen and fractionation monitor of plant extracts for 3ps activity. the modified assay was performed on a series of natural compounds and plant extracts (known to have 3ps activity) and on extracts o ... | 1982 | 7161602 |
| retention of tumor markers in f1 progeny plants from in vitro induced octopine and nopaline tumor tissues. | tumorous tobacco shoots have been derived from callus tissues produced by agrobacterium tumefaciens--induced transformation of tobacco protoplasts and by fusion of normal protoplasts with those from crown gall tumors. the continued presence of t-dna sequences in shoots is directly demonstrated by southern blotting and is also revealed by the presence of the tumor markers octopine and nopaline. when grafted onto normal tobacco plants, both octopine- and nopaline-type shoots (including those from ... | 1981 | 7249079 |
| [biological properties of agrobacterium tumefaciens rna-polymerase. i. isolation of rna-polymerase from agrobacterium tumefaciens 8628]. | rna-polymerase is isolated from agrobacterium tumefaciens 8628. when fractioning the protein extract by deae-cellulose, rna-polymerase is separated into three fractions eluated with 0.15, 0.165, and 0.185 m kci. their electrophoresis in polyacrylamide gel shows that the composition of subunits in the second and third fractions is, in principle, similar to that of escherichia coli rna-polymerase, but the first fraction protein distribution pattern differs from he mentioned fractions. the data obt ... | 1980 | 7256932 |
| cell surface carbohydrates of agrobacterium tumefaciens involved in adherence during crown gall tumor initiation. | | 1981 | 7271806 |
| genetic transformation of rhizobium meliloti by plasmid dna. | a procedure for the genetic transformation of rhizobium meliloti by plasmid dna is described. it is an adaptation of a procedure used originally for escherichia coli and later for agrobacterium tumefaciens. depending on the r. meliloti isolate used as the recipient, the efficiency of transformation was in the range of 7 x 10(1) to 3.7 x 10(3) per microgram of plasmid prk248 dna and 10(-6) to 10(-9) per viable cell. a number of different naturally occurring strains could be transformed. plasmids ... | 1981 | 7297855 |
| distribution of cytokinin-active nucleosides in isoaccepting transfer ribonucleic acids from agrobacterium tumefaciens. | the cytokinin-active isoprenoid nucleosides of agrobacterium tumefaciens transfer ribonucleic acid were identified by high-pressure liquid chromatography, permethylation, and mass spectroscopy. besides the expected 6-[(3-methylbut-2-enyl)amino]-9-(beta-d-ribofuranosyl)purine (i6a) and its 2-methylthio derivative (ms2i6a), substantial amounts of cis- and trans-ribosylzeatin (io6a) and cis-2-(methylthio)ribosylzeatin (c-ms2io6a) were present. these hydroxylated side chain derivatives are normally ... | 1981 | 7306490 |
| agrobacterium tumefaciens rna polymerase: a new purification procedure and a study of the stable binding sites on homologous deoxyribonucleic acid. | rna polymerase (rna nucleotidyltransferase, ec 2.7.7.6) of agrobacterium tumefaciens has been purified according to a fast and efficient procedure. the method involves only two chromatographic steps and yields a highly active enzyme. the rna polymerase was studied with respect to the ability to bind its homologous genome. a. tumefaciens deoxyribonucleic acid (dna) binds the enzyme even when fragmented at undergenic size (300 base pairs). the general binding is unspecific and very labile at low c ... | 1981 | 7306497 |
| transposition of tn904 encoding streptomycin resistance into the octopine ti plasmid of agrobacterium tumefaciens. | a transfer-deficient derivative of plasmid rp1-pmg1 was isolated after insertion of mu cts62. the tra- r plasmid was used to donate tn904, encoding streptomycin resistance, to ti plasmid pal102 harbored by agrobacterium tumefaciens ach5. under conditions promoting high ti transfer frequencies, 155 strains were isolated in which the streptomycin marker coupled with ti plasmid in further transfer experiments. these isolates represent stable insertions of tn904 into the ti plasmid. in addition, 19 ... | 1980 | 7353997 |
| occurrence and levels of cis-and trans-zeatin ribosides in the culture medium of a virulent strain of agrobacterium tumefaciens. | | 1980 | 7358157 |
| diversity among b6 strains of agrobacterium tumefaciens. | a total of 20 laboratory substrains of agrobacterium tumefaciens strain b6 were compared with respect to six characteristics, including 3-ketolactose production, lysogeny, octopine catabolism, tumorigenic host range, and plasmid content. within this group of strains diversity was found for all characteristics except 3-ketolactose production. six substrains were lysogenized with an omega-type phage, whereas one substrain appeared neither sensitive to nor lysogenized with this bacteriophage. all b ... | 1980 | 7364725 |
| interactions between octopine and nopaline plasmids in agrobacterium tumefaciens. | transfer of octopine ti plasmids to strains already carrying an octopine ti plasmid was found to occur at the same (high) frequency as transfer to ti plasmid lacking recipients, showing that resident ti plasmids do not exhibit entry exclusion towards incoming ti plasmids. the resident octopine ti plasmid was lost by the recipient after the entrance of the incoming ti plasmid, which is indicative of the incompatibility between the ti plasmids. octopine ti plasmids were found to become established ... | 1980 | 7410319 |
| [ti plasmids of agrobacterium tumefaciens and their role in the formation of plant tumors]. | | 1980 | 7421799 |
| agrobacterium radiobacter prosthetic valve endocarditis. | | 1980 | 7447191 |
| elaboration of cellulose fibrils by agrobacterium tumefaciens during attachment to carrot cells. | the attachment of virulent strains of agrobacterium tumefaciens to plant cells is the first step in the bacterial induction of tumors. binding of a. tumefaciens to carrot tissue culture cells occurred as a two-step process. the initial step was the attachment of the bacteria to the plant cell wall. living plant cells were not required. bacterial attachment to heat-killed or glutaraldehyde-fixed carrot cells proceeded with only slightly altered kinetics and unaltered bacterial strain specificity. ... | 1981 | 7462151 |
| high angle and ligand-induced low angle dna bends incited by occr lie in the same plane with occr bound to the interior angle. | the occr protein of agrobacterium tumefaciens activates transcription of the occq operon in response to octopine. octopine shortens the dnase i footprint of occr and relaxes an occr-incited dna bend. in this study, we used hydroxyl radical footprinting to show that occr contacts only one face of the operator. this contact spans 50 nucleotide pairs in the absence of octopine, and 39 nucleotide pairs in the presence of octopine. octopine enhanced protection of the central region of the footprint. ... | 1995 | 7473714 |