Publications
| Title | Abstract | Year(sorted ascending) Filter | PMID Filter |
|---|
| role and specificity of plasmid rp4-encoded dna primase in bacterial conjugation. | the role of the dna primase of incp plasmids was examined with a derivative of rp4 containing tn7 in the primase gene (pri). the mutant was defective in mediating bacterial conjugation, with the deficiency varying according to the bacterial strains used as donors and recipients. complementation tests involving recombinant plasmids carrying cloned fragments of rp4 indicated that the primase acts to promote some event in the recipient cell after dna transfer and that this requirement can be satisf ... | 1986 | 3522540 |
| lincomycin stimulates synthesis of tem-2 beta-lactamase by escherichia coli. | lincomycin increased the tem-2 beta-lactamase activity of escherichia coli k-12 cells carrying plasmid rp4 at a concentration which slightly inhibited cell growth. in a control culture beta-lactamase activity reached its maximal level in late log phase, whereas when lincomycin was present beta-lactamase activity continued to increase into the stationary phase. lincomycin (100 micrograms/ml) inhibited both cell growth and protein synthesis by about 35% but stimulated beta-lactamase activity 2.5-f ... | 1986 | 3530127 |
| [molecular cloning and functional analysis of dna regions of plasmid rp4 determining the incompatibility properties]. | sau3a-generated dna fragments determining incompatibility functions of the plasmid rp4 were cloned on the vectors ptk16 and pbr322. inc+ recombinant plasmids were divided into two types: 1) expressing incompatibility only towards the homologous rp4 replicon, 2) expressing incompatibility - both towards the homologous rp4 replicon and towards the heterologous replicons of plasmids r906 and r751. for one member of the first type plasmids it was shown that the cloned inc+-specific insertion derived ... | 1986 | 3021575 |
| [effective, plasmid rp4-dependent replication-transposition of dna of the transposable phage d3112 of pseudomonas aeruginosa in a heterologous escherichia coli system]. | the processes of replication and transposition of pseudomonas aeruginosa transposable phage d3112 in cells of escherichia coli (d3112) and e. coli (rp4::d3112) were studied. d3112 genome is a "silent cassette" ("conex-phage"--conditionally expressible) in e. coli cells incubated at 42 degrees c. two compulsory conditions for d3112 genome expression are incubation at 30 degrees c and the presence in cells of rp4 plasmid. processes of replication and transposition in e. coli are coupled. rp4 plasm ... | 1986 | 3021578 |
| cloning of the cyo locus encoding the cytochrome o terminal oxidase complex of escherichia coli. | the structural genes encoding the cytochrome o terminal oxidase complex (cyo) of escherichia coli have been subcloned into the multicopy plasmid pbr322 after the mu-mediated transposition of the gene locus from the bacterial chromosome onto the conjugative r plasmid rp4. introduction of cyo plasmids into strains (cyo cyd) lacking both terminal oxidases restored the ability of the strains to grow aerobically on nonfermentable substrates. strains carrying the cyo plasmids produced 5 to 10 times mo ... | 1987 | 3036778 |
| [genetic determination of the vibriocinogenicity trait in vibrio cholerae of the el tor biotype]. | in two different strains of cholera vibrios two reca-dependent plasmids, pvib i (1.9-2.2 md) and pvib ii (5.2-5.8 md), have been detected. these plasmids determine the synthesis of vibriocin, coagulase and fibrinolysin, which has been established by the cotransformation of the dna of plasmids pvib i and pbr322 and by the transfer mobilization with the use of plasmid rp4. | 1987 | 3303760 |
| nucleotide sequence of the kanamycin resistance determinant of plasmid rp4: homology to other aminoglycoside 3'-phosphotransferases. | the kanamycin resistance determinant of the broad-host-range plasmid rp4 encodes an aminoglycoside 3'-phosphotransferase of type i. the nucleotide sequence of the kanamycin resistance gene (kmr) and the right end of the insertion element is8 of plasmid rp4 has been determined. the gene (816 bp) is located between is8 and the region (tra 1) encoding plasmid factors mediating bacterial conjugation. kmr and tra 1 are transcribed toward each other. the nucleotide sequence has been compared to five r ... | 1987 | 2832861 |
| mode of insertion of the broad-host-range plasmid rp4 and its derivatives into the chromosome of myxococcus xanthus. | the mode of insertion of the broad-host-range plasmid rp4 into the chromosome of myxococcus xanthus strain dz1 has been analyzed. the plasmid integrated in numerous sites of the chromosome and generated insertional mutations. there is a hot spot of integration located between 31.5 and 34.5 kb clockwise from the ecori site of the plasmid. in the absence of this segment the insertion can, however, take place, but much less efficiently. the presence of transposable elements on the plasmid decreases ... | 1987 | 2829249 |
| expression of degradative genes of pseudomonas putida in caulobacter crescentus. | the recombinant plasmid rp4-tol was transferred into caulobacter crescentus at a high frequency, and the plasmid was maintained for at least 50 generations. c. crescentus cells which contained rp4-tol grew on all the aromatic compounds that the plasmid normally allowed pseudomonas putida to grow on. reciprocal transfers from c. crescentus donor to p. putida or escherichia coli recipients were less efficient and occurred at frequencies of approximately 10(-3). some representative tol-specified en ... | 1987 | 3597317 |
| [isolation of the r'his plasmids of vibrio cholerae]. | v. cholerae strain vt5104 capable of donor activity in conjugation has been constructed by the genetic technique based on plasmid rp4::mucts62 integration into v. cholerae chromosome due to plasmid homology with mucts62 inserted into the chromosome. the gene for histidine synthesis has been mobilized and transferred into the recipient cells from vt5104 donor. the conjugants obtained are able to efficiently transfer his+ gene included into the plasmid structure in conjugation with eltor recipient ... | 1987 | 3474038 |
| [localization of structural genes of vibrio cholerae cholerae toxin using the recombinant plasmid rp4omega elt]. | the recombinant plasmid rp4 omega elt carrying escherichia coli heat-labile enterotoxin elt genes with 70-80% homology with genes vct of vibrio cholerae has been constructed. we used this plasmid to determine localization of the cholerae toxin genes vct on the map of vibrio cholerae cholerae. two types of the donors were revealed in matings of 10 strains of v. cholerae cholerae 569b/rp4 omega elt with the polyauxotrophic recipients rv31 and rv175: some strains had enhanced frequency of mobilizat ... | 1987 | 3319775 |
| mini-mu transposition of bacterial genes on the transmissible plasmid. | using the prm30 plasmid, an aps deletion derivative of broad host range plasmid rp4 with integrated new minimu 5 (11 kb), we followed the transfer of escherichia coli chromosomal genes to the recipient strain. the minimu 5-mediated transposition of chromosomal genes occurs onto the plasmid with integrated minimu 5 rather than onto the "recipient" plasmid pnh602. the plasmid dna in recipient cells was detected by electrophoresis. one of the acquired hybrid plasmids ptb2 was analyzed genetically a ... | 1987 | 2826318 |
| [sos-induction of the rp4 plasmid tet-determinant]. | induction of the tetracycline-resistance genes function by the inducer of the dna-repair and mutability sos-system, uv-light, has been tested. activity of the tet-genes residing on the plasmid rp4 in escherichia coli cells has been shown to be inducible by the low doses of tetracycline as well as by the mutagenic doses of uv-light. the induction was quantitatively registered by measuring the activity of beta-galactosidase of bacteriophage mud1 (ap, lac) inserted into the tet-genes of the plasmid ... | 1988 | 2848194 |
| transfer of incp plasmids into stigmatella aurantiaca leading to insertional mutants affected in spore development. | derivatives of the broad-host-range plasmid rp4, containing the wild-type or modified transposon tn5 were transferred by conjugation to various stigmatella aurantiaca isolates. the transposons and in some cases fragments of the plasmid as well were integrated into the chromosome. thus, insertional mutants have been obtained affected in spore formation in liquid culture. | 1988 | 2853291 |
| transfer of the ti plasmid from agrobacterium tumefaciens into escherichia coli cells. | we have screened strains of agrobacterium tumefaciens for spontaneous mutants showing constitutive transfer of the nopaline ti plasmid ptic58 during conjugation. the ti plasmid derivatives obtained could be transferred not only to a. tumefaciens but also to e. coli cells. the ti plasmid cannot survive as a freely replicating plasmid in e. coli, but it can occasionally integrate into the e. coli chromosome. however, insertion in tandem of plasmids carrying fd replication origins (pfd plasmids) in ... | 1988 | 3049936 |
| effects of lincomycin on synthesis of tem beta-lactamase by escherichia coli. | sub-inhibitory concentrations of lincomycin slightly inhibit growth of escherichia coli carrying plasmid rp4 and cause a 2-fold increase in tem-2 beta-lactamase. to analyze this effect, cultures were pulse-labeled with [3h]leucine, chased with non-radioactive leucine and immunoprecipitated with anti-beta-lactamase antiserum. the synthesis rate of beta-lactamase was two times higher in inhibited cultures than in control cultures. no significant decrease of labeled enzyme occurred during the 30 mi ... | 1988 | 3290174 |
| [compatibility of transposable phages of escherichia coli and pseudomonas aeruginosa. i. co-development of phages mu and d3112 and integration of phage d3112 into rp4::mu plasmid in pseudomonas aeruginosa cells]. | the possibility of using a model system (which included rp4::mu plasmid and d3112 phage in pseudomonas aeruginosa cells) for analysis of compatibility of transposable escherichia coli phage mu and p. aeruginosa phage d3112, as phages and transposons, was studied. no interaction was observed during the vegetative growth of phages. the majority of the hybrid rp4::mu plasmids lost the mu dna after insertion of d3112 into rp4::mu. the phenomenon was not a result of transposition immunity. we conside ... | 1988 | 2840341 |
| construction of transposons carrying the transfer functions of rp4. | the transfer genes and origin of transfer of the wide host range plasmid rp4 have been cloned into the transposons tn1 and tn5. the newly constructed transposons can be used to mutagenize bacterial plasmids or the chromosome in species such as escherichia coli or rhizobium. it is then possible to mobilize the plasmid or chromosome using the transfer functions provided in cis by the transposon. these constructs may aid chromosome mapping in many gram-negative species by allowing the wider use of ... | 1988 | 2854282 |
| physical and functional mapping of two cointegrate plasmids derived from rp4 and tol plasmid pdk1. | cointegrate plasmids were formed in vivo between the broad-host-range r-plasmid rp4 and two catabolic plasmids derived from pseudomonas putida hs1. one of these was the wild-type plasmid pdk1 encoding the complete inducible toluene/xylene (tol) catabolic pathway and one was pdkt1, a deletion derivative of pdk1 selected after growth of hs1 on benzoate and supporting growth on only toluene. the two plasmids formed, pdk2 and pdkt2 respectively, each consisted of a complete rp4 replicon in which was ... | 1988 | 3076182 |
| mini-mulac transposons with broad-host-range origins of conjugal transfer and replication designed for gene regulation studies in rhizobiaceae. | novel mini-mu derivatives were constructed, carrying a truncated laczya operon fused to the terminal 117 bp of the mu s-end, for the isolation of translational lac fusions by mini-mu-mediated insertion mutagenesis. different selectable markers (chloramphenicol resistance; gentamycin resistance) were introduced to allow selection for mini-mu insertions in different replicons and bacterial strains. a mini-mulac derivative carrying the site for conjugal transfer of plasmid rp4 (orit) and the origin ... | 1988 | 2838383 |
| two mechanisms necessary for the stable inheritance of plasmid rp4. | plasmid rp4 is stably maintained in strains of escherichia coli and other gram-negative bacteria. inactivation of the plasmid primase gene (pri) or removal of the pstic fragment gave rp4 derivatives that are slightly unstably maintained in e. coli. removal of the tn 1 multimer resolution system (res and tnpr) did not lead to any detectable plasmid loss. removal of all three of these regions, however, gave rise to pnj5000 which is lost at high frequency. we have dissected the mechanisms causing t ... | 1989 | 2699039 |
| anaerobic growth of escherichia coli on glycerol by importing genes of the dha regulon from klebsiella pneumoniae. | the dha regulon of klebsiella pneumoniae specifying fermentative dissimilation of glycerol was mobilized by the broad-host-range plasmid rp4:mini mu and introduced conjugatively into escherichia coli. the recipient e. coli was enabled to grow anaerobically on glycerol without added hydrogen acceptors, although its cell yield was less than that of k. pneumoniae. the reduced cell yield was probably due to the lack of the coenzyme-b12-dependent glycerol dehydratase of the dha system. this enzyme in ... | 1989 | 2559947 |
| lack of expression of rp4-specified beta-lactamase in azospirillum brasilense. | plasmid rp4, which normally confers resistance to ampicillin (apr), tetracycline (tcr), and kanamycin (kmr) to its hosts, failed to express enhanced apr when transferred from escherichia coli to azospirillum brasilense which has its own intrinsic beta-lactamase. even in a beta-lactamase-deficient mutant, a. brasilense rg-d16, no increase in beta-lactamase or significant apr appeared following transfer of rp4. however, a. brasilense rg (rp4) and a. brasilense rg-d16 (rp4) did exhibit tcr kmr. whe ... | 1989 | 2699042 |
| traj protein of plasmid rp4 binds to a 19-base pair invert sequence repetition within the transfer origin. | transfer of plasmid rp4 during bacterial conjugation requires the plasmid-encoded traj protein, which binds to the transfer origin (fürste, j. p., pansegrau, w., ziegelin, g., kröger, m., and lanka, e. (1989) proc. natl. acad. sci. u.s.a. 86, 1771-1775). as indicated by traj mutants, the traj protein is a constituent of the relaxosome, the initiation complex of transfer dna replication. the traj gene maps adjacent to the transfer origin (orit). the structural gene consists of a 372-base pair seq ... | 1989 | 2663846 |
| transfer and properties of some natural and suicide replicons in pasteurella multocida. | we tested the transfer of several plasmids and transposons from escherichia coli to pasteurella multocida by filter mating. two plasmids, prktv5 (prk2013::tn7) and puw964 (prktv5::tn5), were derived from prk2013--a narrow-host-range plasmid with the broad-host-range incp conjugation genes. most p. multocida transconjugants obtained with prktv5 had tn7 insertions in the chromosome but some had insertions of the whole plasmid. by contrast, all the transconjugants obtained with puw964 had insertion ... | 1989 | 2561489 |
| survival of and plasmid stability in pseudomonas and klebsiella spp. introduced into agricultural drainage water. | cell survival and plasmid stability in pseudomonas fluorescens r2f and pseudomonas putida cym 318 containing respectively, plasmid rp4 and prk2501, and klebsiella aerogenes nctc 418 harboring plasmid pbr322 were studied in sterile and nonsterile agricultural drainage water under both aerobic and anaerobic conditions and in the absence and presence of added nutrients. both pseudomonas strains survived well in sterile drainage water incubated aerobically, with or without added nutrients. however, ... | 1989 | 2590305 |
| direct selection for curing and deletion of rhizobium plasmids using transposons carrying the bacillus subtilis sacb gene. | we have constructed derivatives of the transposon tn5 carrying the mob site (orit) of plasmid rp4, and an npti-sacb-sacr cassette [ried and collmer, gene 57 (1987) 239-246]. the mob site, in conjunction with the antibiotic-resistance markers carried on the transposons, allows identification of transposon inserts in cryptic plasmids by mobilisation to other strains. the sacb-sacr genes allow direct selection for the loss or curing of plasmids, because only strains which no longer contain an activ ... | 1989 | 2548927 |
| isr1, a transposable dna sequence resident in rhizobium class iv strains, shows structural characteristics of classical insertion elements. | isr1 is a small transposable element, identified in rhizobium class iv strains by its high frequent mutagenic insertion into plasmid rp4. hybridization studies showed that isr1 is present in, multiple copies in rhizobium class iv strains. nucleotide sequence analysis revealed that isr1 has a length of 1260 bp and is characterized by perfect inverted repeats of 13 nucleotides followed by a stretch of 28/29 nucleotides with imperfect homology. the insertion under study generated a target site dupl ... | 1989 | 2544911 |
| conjugative transfer of promiscuous incp plasmids: interaction of plasmid-encoded products with the transfer origin. | to characterize protein-dna interactions involved in the initiation of conjugative transfer replication, we isolated and sequenced the transfer origins (orit) of the promiscuous incp plasmids rp4 and r751. the central initiating event at the transfer origin of a conjugative plasmid is the cleavage at a unique site (nic) of the strand to be transferred to a recipient cell. this process can be triggered after the assembly of "relaxosomes" (plasmid dna-protein relaxation complexes), requiring plasm ... | 1989 | 2538813 |
| establishment of gene transfer systems for and construction of the genetic map of a marine vibrio strain. | two gene transfer systems were established for a marine bacterium, vibrio sp. strain 60. one was generalized transduction with a newly isolated bacteriophage, as3, and the other was conjugal gene transfer by the use of newly constructed transposon-facilitated recombination (tfr) donors. as3 transduced various chromosomal markers at frequencies of 10(-4) to 10(-6). tfr donors, which were constructed by introducing transposon tn10 into both plasmid rp4 and the chromosome, mediated the polarized tr ... | 1989 | 2539353 |
| [change in the ultrastructure of the cell wall of bacillus cereus, determined by rp4 mucts62 plasmid]. | the influence of plasmid rp4 mucts62, heterologous for b. cereus, on the growth rate of b. cereus strains ga 682 and 319 obtained in our earlier experiments and on changes in the ultrastructure of their cell walls in comparison with b. cereus initial strains gp 7 and dsm 318 has been studied. plasmid rp4 mucts62 with a wide spectrum of action has been found not only to determine the functional signs of resistance to antibiotics and thermal sensitivity in the heterologous host, but also to take p ... | 1989 | 2499144 |
| partitioning of broad-host-range plasmid rp4 is a complex system involving site-specific recombination. | the broad-host-range plasmid rp4 encodes a highly efficient partitioning system (par) that was previously mapped within the 6.2-kb psti c fragment. the essential functions were assigned to a region of 2.2 kb between fiwa and is21 (is8). on the basis of the nucleotide sequence data of the entire par locus and of in vitro and in vivo expression studies, three distinct loci encoding polypeptides of 9, 18, and 24 kda were identified. evidence for the expression of another polypeptide was found. a pu ... | 1990 | 2172207 |
| plasmid rp4 host-lethal function kila and its repressor kora sequences are part of the cryptic tellurite resistance transposon tn521. | the normally silent 4.5 kb tellurite resistance transposon tn521 of rp4 has been shown to carry sequences from both the flanking kila and kora loci of this broad host range plasmid. the major portion of both of these sequences were used as probes to examine dna homology in southern transfer hybridization experiments with plasmid recipients of tn521 chosen from varying incompatibility groups. in the case of every recipients molecule analyzed using either probe, dna homology was observed. | 1990 | 2165965 |
| cloning and analysis of rfb gene synthesizing the mannan 0 side chain of escherichia coli 09 lipopolysaccharide. | the rfb gene encoding the proteins responsible for the synthesis of the repeating units (o side-chain) of escherichia coli 09 lipopolysaccharide was cloned into a conjugative plasmid rp4::minimu and was expressed in e. coli k-12. | 1990 | 2183549 |
| [the multiple effect of plasmid rp4::mu cts 62 in transcipient bacilli]. | transfer of conjugative hybrid plasmid rp4::mu cts 62 from escherichia coli into bac. cereus, bac. thuringiensis, bac. mesentericus and bac. polymyxa cells led to the multiple effects on the structure and physiology of bacillus cells. it has resulted in a decrease of the bacillus vitality, in the accelerated autolytic decay of cells, in the delay of cell growth and reproduction rate in liquid and solid media, in the disruption of ultrastructure of the cell membrane and its surface layer. | 1990 | 2273994 |
| influence of glycine betaine on the transfer of plasmid rp4 between escherichia coli strains in marine sediments. | the conjugative transfer of plasmid rp4 between two strains of escherichia coli in a sterile marine sediment was enhanced by the presence of glycine betaine (frequency increased 20 to 40 times). the conjugation was also facilitated by the osmoprotection of donor cells. glycine betaine is a universal osmolyte and has been found in marine sediments at high concentrations. so this phenomenon could have epidemiological and sanitary importance by increasing the possibility of dissemination of some pl ... | 1990 | 1366575 |
| in vitro assembly of relaxosomes at the transfer origin of plasmid rp4. | during initiation of conjugative transfer of dna containing the transfer origin (orit) of the promiscuous plasmid rp4, the proteins trai, traj, and trah interact and assemble a specialized nucleoprotein complex (the relaxosome) at orit. the structure can be visualized on electron micrographs. site- and strand-specific nicking at the transfer origin in vitro is dependent on the proteins trai and traj and on mg2+ ions. substrate specificity is directed exclusively towards the cognate transfer orig ... | 1990 | 2168553 |
| [the genetic transfer, heredity and phenotypic expression of plasmid rp4::mu cts genes in bacillus cereus]. | the transcipients were obtained in intrageneric matings of e.coli donor harbouring the plasmid pr4::mu cts 62 with bac. cereus gp7 recipient cells with the frequency 10(-9). the transcipient clone bac. cereus 682 was selected having stably inherited and expressed the hybrid plasmid pr4::mu cts 62 genes for antibiotic resistance and temperature sensitivity. production of the bacteriophage mu cts 62 particles was not registered in the bacillary transcipient cells. the plasmid rp4::mu cts 62 genes ... | 1990 | 2114185 |
| [the infection of bacilli by mu cts phage integrated into the plasmid]. | the infection of bacillus thuringiensis, b. cereus, b. mesentericus and b. polymyxa strains with temperate e. coli bacteriophage mu cts62 integrated into plasmid rp4 under conditions of conjugative transfer is shown possible. the investigated strains of bacilli are not able to produce intact phage particles but they acquire the thermosensitive property determined by the phage genome. gel electrophoresis and blot hybridization of dna have confirmed the transfer of mu cts62 genome or a part of it ... | 1990 | 2145498 |
| [isolation of transmissible cointegrates of yersinia pestis plasmids pyv and pyt with the plasmid rp4::mu cts 62, incp1]. | the transmissible cointegrates of the yersinia pestis plasmids pyv and pyt with the broad host range plasmid rp4::mu cts62 of the incompatibility group incp have been constructed by the in vivo recombination. the cointegrative plasmid pkr14 (pyv76 omega rp4::mu cts62) conferred on the transconjugants the properties of ca2(+)-dependence at 37 degrees c, v-antigen synthesis, rp4 plasmid markers (apr, kmr, tcr), immunity to the lysis by the bacteriophage mu cts62 and incompatibility with the homolo ... | 1990 | 2233780 |
| mobilization of escherichia coli r1 silver-resistance plasmid pjt1 by tn5-mob into escherichia coli c600. | escherichia coli r1 is an ag(+)-resistant strain that, as we have shown recently, harbours at least two large plasmids, pjt1 (83 kb) and pjt2 (77 kb). tn5-mob was introduced into the e. coli r1 host replicon via conjugation on membrane filters. the transfer functions of plasmid rp4-4 were provided in this process and tn5-mob clones mated with e. coli c600 yielded ag(+)-resistant transconjugants. this mobilization procedure allowed transfer and expression of pjt1 ag+ resistance in e. coli c600. p ... | 1990 | 2169281 |
| mechanism of integration of the broad-host-range plasmid rp4 into the chromosome of myxococcus xanthus. | the site-specific recombination mechanism through which the plasmid rp4 has been previously shown to integrate into the chromosome of myxococcus xanthus has been investigated further. once integrated in one of the numerous chromosomal sites from two different strains, through a precise site on the plasmid, the latter can be excised either precisely or after a definite 14.5-kb deletion. in some cases, the integration is followed by different dna rearrangements that yield a higher rate of excision ... | 1990 | 2120716 |
| silver accumulation and resistance in escherichia coli r1. | e. coli r1 contains at least 2 large plasmids (83 and 77 kb) while e. coli s1 was previously cured of the 83 kb plasmid. transformation using artificial competence, high-voltage electroporation, and plasmid mobilization experiments with the mobilizing plasmid rp4, failed to ascertain the 83 kb plasmid was responsible for ag(+)-resistance. silver accumulation by an ag(+)-sensitive e. coli s1 strain was 5-fold higher than an ag(+)-resistant e. coli r1 strain. the ag(+)-resistant e. coli r1 strain ... | 1990 | 2202786 |
| covalent association of the trai gene product of plasmid rp4 with the 5'-terminal nucleotide at the relaxation nick site. | formation of relaxosomes is the first step in the initiation of transfer dna replication during bacterial conjugation. this nucleoprotein complex contains all components capable of introducing a site- and strand-specific nick at a cognate transfer origin (orit) on supercoiled plasmid dna, thus providing the substrate for generation of the strand to be transferred. characterization of the terminal nucleotides at the orit nick site revealed that relaxation occurs by hydrolysis of a single phosphod ... | 1990 | 2191955 |
| [erwinia carotovora as a recipient system for the natural hybrid plasmid rp4::mu cts62]. | the plasmid rp4::mu cts62 is transferred from escherichia coli cells into a recipient strain erwinia carotovora 268 by conjugation with the frequency 1.5-5 x 10(-7) per donor cell. the maximal frequencies of transfer are obtained by cultivation of donor and recipient cells for 3-5 h on the filters. structural and functional validity of the plasmid in transconjugants is expressed in preservation of all antibiotic-resistant markers of rp4, thermosensitivity to growth at 42 degrees c as well as spo ... | 1990 | 2175013 |
| conjugal transfer of megaplasmid 2 between rhizobium meliloti strains in alfalfa nodules. | a dna fragment containing the rp4 mob function, as well as the gentamicin and spectinomycin resistance genes, was inserted by gene replacement onto the megaplasmid 2 (pm2) of rhizobium meliloti 0540 (inf eps), resulting in pg101 (inf eps). the self-transfer of pm2 and the mobilization of pm2 by plasmid rp4-4 were investigated during conjugation between pg101 and r. meliloti 2526 (nod). in filter conjugations, pm2 was readily mobilized by rp4-4. in addition to this, the self-transfer of one megap ... | 1990 | 16348248 |
| detection of plasmid transfer from pseudomonas fluorescens to indigenous bacteria in soil by using bacteriophage phir2f for donor counterselection. | the transfer of a genetically marked derivative of plasmid rp4, rp4p, from pseudomonas fluorescens to members of the indigenous microflora of the wheat rhizosphere was studied by using a bacteriophage that specifically lyses the donor strain and a specific eukaryotic marker on the plasmid. transfer of rp4p to the wheat rhizosphere microflora was observed, and the number of transconjugants detected was approximately 10 transconjugants per g of soil when 10 donor cells per g of soil were added; tr ... | 1991 | 16348599 |
| characterization and classification of actinobacillus (haemophilus) pleuropneumoniae plasmids. | actinobacillus (haemophilus) pleuropneumoniae plasmids were characterized and classified. they were isolated from a pleuropneumoniae strains different in serotype, year isolated, or location from which isolated. six of 8 plasmids encoded streptomycin (sm) and sulfonamide (su) resistance (smsu). one of the other plasmids, pvm105, encoded ampicillin (ap) resistance and another, phm0, encoded no drug resistance. all smsu plasmids were transferred to escherichia coli strains by transformation. among ... | 1991 | 1785724 |
| electroporation and conjugal plasmid transfer to members of the genus aquaspirillum. | electroporation methods and conjugal matings were used to transfer several plasmid vectors to aquaspirillum dispar and aquaspirillum itersonii. the incompatibility p class plasmid rp4 was conjugally transferred from escherichia coli hb101 to these spirilla, and the transconjugants subsequently donated the molecule to plasmid-free e. coli and a. dispar strains via conjugal matings. high-voltage electrotransformation was used to transfer plasmids pucd2, psa151 and rp4 to a. dispar and a. itersonii ... | 1991 | 1907445 |
| competition between strains of escherichia coli with and without plasmid rp4 during chemostat growth. | escherichia coli strains j53(nal) and j53(rp4) were grown together in glucose-limited continuous cultures. based on the measured growth kinetic constants of the two strains, take-over of the cultures by j53(rp4) was predicted. however, in practice, an initial period of predominance by j53(rp4) was always followed by a prolonged period in which relative numerical proportions of the two strains oscillated widely. this period of oscillation was removed or greatly reduced when the difference between ... | 1991 | 1913355 |
| a thiostrepton-inducible expression vector for use in streptomyces spp. | a shuttle expression vector containing the thiostrepton-inducible streptomyces lividans promoter, ptipa, and the origin of transfer from plasmid rp4 was constructed. cassettes containing a promoterless xyle gene upstream from a hyg gene were used to demonstrate thiostrepton-inducible expression from ptipa in both s. lividans and streptomyces ambofaciens, ptipa was estimated to be induced 60-fold or more in streptomyces ambofaciens. | 1991 | 1879704 |
| nucleotide sequence and organization of genes flanking the transfer origin of promiscuous plasmid rp4. | the nucleotide sequence of the relaxase operon and the leader operon which are part of the tra1 region of the promiscuous plasmid rp4 was determined. these two polycistronic operons are transcribed divergently from an intergenic region of about 360 bp containing the transfer origin and six close-packed genes. a seventh gene completely overlaps another one in a different reading frame. conjugative dna transfer proceeds unidirectionally from orit with the leader operon heading the dna to be transf ... | 1991 | 1665997 |
| construction of a mobilizable cloning vector for site-directed mutagenesis of gram-negative bacteria: application to rhizobium leguminosarum. | a mobilizable cloning vector was constructed from defined fragments to serve as a suicide plasmid for site-directed mutagenesis. the new vector, pkok4, closely resembles plasmid pbr325. however, the inverted duplication existing in the latter was not introduced. the useful cloning sites of pbr325 (ecori, hindiii, ecorv, bamhi, sali, psti and pvui) were retained and are located in one of the three resistance markers, apr, cmr or tcr, respectively. also, in pkok4 the cmr gene retains its own promo ... | 1991 | 2013412 |
| dissection of incp conjugative plasmid transfer: definition of the transfer region tra2 by mobilization of the tra1 region in trans. | we constructed a transfer system consisting of two compatible multicopy plasmids carrying the transfer regions tra1 and tra2 of the broad-host-range incp plasmid rp4. in this system, the plasmid containing the tra1 region with the origin of transfer (orit) was transferred, whereas additional functions essential for the conjugative process were provided from the tra2 plasmid in trans. the tra2 region, as determined for matings between escherichia coli cells, maps between coordinates 18.03 and 29. ... | 1992 | 1556069 |
| sequence similarities between the rp4 tra2 and the ti virb region strongly support the conjugation model for t-dna transfer. | transfer genes of the incp plasmid rp4 are grouped in two separate regions, designated tra1 and tra2. tra2 gene products are proposed to be mainly responsible for the formation of mating pairs in conjugating cells. to provide information relevant to understanding the function of tra2 gene products, the nucleotide sequence of the entire rp4 tra2 region is presented here. twelve open reading frames were identified in the tra2 core region, being essential for intraspecific escherichia coli matings. ... | 1992 | 1400366 |
| korb protein of promiscuous plasmid rp4 recognizes inverted sequence repetitions in regions essential for conjugative plasmid transfer. | we have constructed a rp4 korb overproducing strain and purified the protein to near homogeneity. korb is a dna binding protein recognizing defined palindromic 13-bp sequences (tttagcsgctaaa). inverted sequence repetitions of this type, designated ob, are present on rp4 12 times. ob-sequences are localized in replication and maintenance regions as well as in the regions tra1 and tra2 essential for conjugative transfer. all sites found in tra regions by computer search act as targets for specific ... | 1992 | 1579485 |
| a directional, high-frequency chromosomal mobilization system for genetic mapping of rhizobium meliloti. | a system for mapping of the rhizobium meliloti chromosome that utilizes transposon tn5-mob, which carries the mobilization site of incp plasmid rp4 (r. simon, mol. gen. genet. 196:413-420, 1984), was developed. insertions of tn5-mob that were located at particular sites on the r. meliloti chromosome were isolated and served as origins of high-frequency chromosomal transfer when incp tra functions were provided in trans. this approach is, in principle, applicable to any gram-negative bacterium in ... | 1992 | 1309521 |
| sequence analysis and characterization of the mobilization region of a broad-host-range plasmid, ptf-fc2, isolated from thiobacillus ferrooxidans. | the nucleotide sequence of a 5,317-bp fragment which includes the region required for mobilization of broad-host-range plasmid ptf-fc2 was determined. a region of approximately 3.5 kb was required for plasmid mobilization, and orit was localized on a 138-bp fragment. polypeptides which corresponded in size and location to several of the open reading frames were detected in an in vitro transcription-translation system. three open reading frames essential for plasmid mobilization and two which aff ... | 1992 | 1400173 |
| trak protein of conjugative plasmid rp4 forms a specialized nucleoprotein complex with the transfer origin. | conjugative transfer of the self-transmissible incp plasmid rp4 requires the product of the rp4 trak gene. by using the phage t7 expression system, the trak gene product was efficiently overproduced and purified to near homogeneity. trak encodes a basic protein (pi = 10.7) of 14.6 kda that, as shown by dna fragment retention assay, interacts exclusively with its cognate transfer origin. the apparent equilibrium constant k(app) for the complex of trak and orit-dna was estimated to be 4 nm. footpr ... | 1992 | 1324929 |
| a natural mutant of plasmid rp4 that confers phage resistance and reduced conjugative transfer. | a natural isolate of rp4 (prc#116) acquired from the stanford university plasmid reference center differed from the wild-type incompatibility group p plasmid in several respects. cells of escherichia coli harboring prc#116 were resistant to the incp pili-specific bacteriophage prd1 and gu5, and transferred this plasmid at a lower efficiency than the wild-type rp4. phage sensitivity was restored, and transfer considerably improved in prc#116+ bacteria transformed with plasmid constructs containin ... | 1992 | 1587464 |
| [mu-induced deletions and mutations of erwinia carotovora chromosomes, including resident prophages e105 and 59]. | the plasmid rp4::mu cts62 in stably inherited by erwinia carotovora 268 strain. under the conditions of thermoinduction bacteriophage mu is segregated and completely eliminated more intensively than in escherichia coli cells. at thermoinduction the transposition of bacteriophage mu cts62 into different chromosomal sites takes place, causing the induction of chlorate resistant and auxotrophic mutants with the frequency of 10(-4). two clones deficient in production of 2 of the 4 resident prophages ... | 1992 | 1406759 |
| [conjugative transfer of plasmid dna between bacteria in soil]. | conjugative transfer of plasmid rp4 between populations of azospirilla and between escherichia coli and azospirillum brasilense in nonsterile soil has been investigated. the process of genetic exchange was realized at the early stages of interpopulational interactions, further on the process intensity was obviously rather low. population dynamics of azospirilla transconjugates in soil depends on the presence or the absence of additional food substrate. | 1992 | 1474945 |
| virulence plasmid pjm1 prevents the conjugal entry of plasmid dna into the marine fish pathogen vibrio anguillarum 775. | studies involving the introduction of cloned homologous genes into vibrio anguillarum revealed that several plasmids could not be conjugally introduced into v. anguillarum 775(pjm1), but were transmissible to the pjm1-cured derivative h775-3. recombinant pbr322 plasmids containing v. anguillarum genomic dna inserts were mobilized from escherichia coli donors, using prk2013, into v. anguillarum h775-3 recipients at frequencies of 10(-6) to 10(-5) per recipient. when identical matings were perform ... | 1992 | 1336793 |
| a gene near the plasmid psa origin of replication encodes a nuclease. | we have cloned and sequenced a gene (nuc) from the incw plasmid psa which shows amino acid sequence similarity to staphylococcal nuclease (ec 3.1.4.7) and to the parb locus of plasmid rp4. the 525 bp open reading frame encodes a 174-amino-acid potential polypeptide of 19.7 kda. expression of the gene was confirmed using an in vitro transcription-translation assay which produced a protein of identical size. nuclease activity was demonstrated using dna as the substrate in toluidine blue-dna agar p ... | 1992 | 1560781 |
| the divergent promoters mediating transcription of the par locus of plasmid rp4 are subject to autoregulation. | the partitioning region of broad-host-range plasmid rp4 contains four genes (para, parb, parc, and pard) that encode products essential for partition activity. two divergently arranged promoters located in the intercistronic region between parc and pard mediate transcription of these genes. the transcriptional initiation sites for both promoters were determined by primer extension. transcriptional fusions were used to show that para, parb, and parc are combined in an operon, while pard constitut ... | 1992 | 1508044 |
| acquisition of a sucrose utilization system in escherichia coli k-12 derivatives and its application to industry. | an escherichia coli strain, b-62, that was isolated from a clinical source and was epidemiologically unrelated to e. coli k-12 was the source of chromosomal dna for a sucrose utilization system (scr+) in the construction of a plasmid, pst621. the cloned insert of a gene encoding scr+ in pst621 conferred a sucrose-positive phenotype onto transformed cells of e. coli k-12 derivatives. sucrase activity of the transformants was as high as that which would correspond to a "gene dosage effect" of a ve ... | 1992 | 1622287 |
| the dehalogenase gene dehi from pseudomonas putida pp3 is carried on an unusual mobile genetic element designated deh. | as a result of the production of two dehalogenases (dehi and dehii), pseudomonas putida pp3 utilized halogenated alkanoic acids, such as 2-monochloropropionic acid (2mcpa), as sole sources of carbon and energy. the dehi gene (dehi) was carried on a mobile genetic element (deh) located on the chromosome of strain pp3. deh recombined with target plasmid dnas at high frequencies (e.g. 3.8 x 10(-4) per rp4.5 plasmid transferred). the regulated expression of dehi was detected in p. putida, pseudomona ... | 1992 | 1312533 |
| transfer of incp plasmids to extremely acidophilic thiobacillus thiooxidans. | the broad-host-range incp plasmids rp4, r68.45, rp1::tn501, and and pub307 were transferred directly to extremely acidophilic thiobacillus thiooxidans from escherichia coli by conjugation at frequencies of 10 to 10 per recipient. the ability of t. thiooxidans to receive and express the antibiotic resistance markers was examined. the plasmid rp4 was transferred back to e. coli from t. thiooxidans at a frequency of 1.0 x 10 per recipient. | 1992 | 16348639 |
| stability of r-microbes: stabilization of plasmid vectors by the partitioning function of broad-host-range plasmid rp4. | the genes for biosynthesis of the biodegradable polymer poly-beta-hydroxybutyric acid (phb) cloned from alcaligenes eutrophus h16 were used for synthesis of phb with recombinant escherichia coli strains. it was recognized that the phb-biosynthesis genes cause segregational instability to the plasmids used as vectors. recombinant phb-plasmids are rapidly lost from host cells and plasmid-free cells occur at high rates, even under conditions of selection for the plasmids. cloning the partitioning r ... | 1993 | 7763562 |
| transfer of plasmid rp4 from escherichia coli k-12 to indigenous bacteria of seawater. | transfer of plasmid rp4 from escherichia coli k-12 donor strain to bacteria isolated from seawater was shown to occur on filters and in sterile seawater incubated at 24 degrees c. ten of 12 seawater isolates tested were recipient active for rp4 when the plasmid transfers were assessed by filter matings. when matings were performed in sterile seawater, seven of the 12 isolates received rp4. in sterile seawater, the transfer of rp4 from e. coli to pseudomonads was more efficient than transfer betw ... | 1993 | 8111533 |
| relaxase (trai) of incp alpha plasmid rp4 catalyzes a site-specific cleaving-joining reaction of single-stranded dna. | conjugative dna transfer of the self-transmissible broad-host-range plasmid rp4 is initiated by strand- and site-specific cleavage at the nick site (nic) of the transfer origin (orit). cleavage results in covalent attachment of the plasmid-encoded relaxase (trai) to the 5'-terminal 2'-deoxycytidine residue at nic. we demonstrate that tyr22 is the center of the catalytic site of trai, mediating cleavage via formation of a phosphodiester between the dna 5' phosphoryl and the aromatic hydroxyl grou ... | 1993 | 8385350 |
| characterization of newly isolated plasmids from actinobacillus pleuropneumoniae. | the genetic basis of drug-resistant strains of actinobacillus pleuropneumoniae in japan was studied. the a pleuropneumoniae strains av277 and av281 that belong to serotype 2 were resistant to streptomycin (sm) and sulfonamide (sa). both strains had an 8.1-kilobase (kb) sm-sa plasmid that was previously classified in the h1 group. the av177 (serotype 1) strain was resistant to sm, sa, ampicillin, and kanamycin (km), but did not have any plasmids. the av319 and av324 (serotype 1) strains were resi ... | 1993 | 8317761 |
| tn5-mob transposon mediated transfer of salt tolerance and symbiotic characteristics between rhizobia genera. | rhizobium meliloti 042b is a fast-growing, salt-tolerant and high efficiency nitrogen-fixing symbiont with alfalfa. bradyrhizobium japonicum usda110 grows slowly, and cannot grow in yma medium containing 0.1m nacl, but nodulates and fixed nitrogen efficiently with soybean. eighty-six transconjugants, called sr, were obtained by inserting tn5-mob randomly into genomes of 042b using psup5011 and helper plasmid rp4. selecting 4 sr strains randomly and introducing dna fragment of sr into usda110 wit ... | 1993 | 8049344 |
| versatile suicide vectors which allow direct selection for gene replacement in gram-negative bacteria. | a set of vector plasmids which greatly facilitate gene replacement and reverse genetics in many gram-negative bacteria was constructed. these vectors are based on the p15a origin of replication (ori) and incorporate sacb from bacillus subtilis, which is inducible by sucrose and is lethal when expressed in gram-negative bacteria. the vectors also have a convenient antibiotic-resistance marker (gentamicin resistance) and the lacz alpha system which allows blue/white selection of cloned fragments. ... | 1993 | 8486283 |
| site-directed mutations in the relaxase operon of rp4. | mutations were constructed by site-directed mutagenesis in the relaxase operon of the broad-host-range plasmid rp4. the mutations were constructed in smaller plasmids, recombined into the 60-kb rp4 plasmid, and tested for their ability to transfer. the relaxase operon contains the transfer genes traj, trah, and trai, which are involved in nicking at the transfer origin to generate the single strand destined to be transferred to the recipient cell. in the first mutant, the c terminus of trai was ... | 1993 | 8335645 |
| changes in cultivar-specificity toward pea can result from transfer of plasmid rp4 and other incompatibility group p1 replicons to pseudomonas syringae pv. pisi. | transfer of rp4 and related replicons belonging to the escherichia coli incompatibility group p (pseudomonas aeruginosa incp1) to races 2 and 6 of p. syringae pv. pisi was associated with the creation of two types of transconjugant, one resembling the parental race and the other showing an altered cultivar-specificity towards pea. the latter, irrespective of the parental race, exhibited a novel pattern of interaction with pea that corresponded to race 4; consequently such transconjugants were te ... | 1993 | 8126435 |
| the vird4 gene is required for virulence while vird3 and orf5 are not required for virulence of agrobacterium tumefaciens. | the vird operon of the resident ti plasmid of agrobacterium tumefaciens contains loci involved in t-dna processing and undefined virulence functions. nucleotide sequence of the entire vird operon of ptic58 revealed similarities to the vird operon of the root-inducing plasmid pria4b and to that of the octopine-type plasmid ptia6nc. however, comparative sequence data show that vird of ptic58 is more akin to that of the pria4b than to that of the ptia6nc. t7f10::vird gene fusions were used to gener ... | 1993 | 8231811 |
| site-specific cleavage and joining of single-stranded dna by vird2 protein of agrobacterium tumefaciens ti plasmids: analogy to bacterial conjugation. | as an early stage of plant transformation by agrobacterium tumefaciens, the ti plasmid is nicked at the border sequences that delimit the t-dna. cleavage results in covalent attachment of vird2 to the 5' terminal of the nicked strand by a process resembling initiation of dna transfer that occurs in the donor cell during bacterial conjugation. we demonstrate that this cleavage can be reproduced in vitro: vird2 protein, the border-cleaving enzyme, was overproduced and purified. cleavage assays wer ... | 1993 | 8265585 |
| resistance to cefoperazone-sulbactam in klebsiella pneumoniae: evidence for enhanced resistance resulting from the coexistence of two different resistance mechanisms. | we investigated the in vitro activity and the in vivo efficacy of the beta-lactam-beta-lactamase inhibitor combination cefoperazone-sulbactam against an isogenic series of klebsiella pneumoniae strains. both cefoperazone and cefoperazone-sulbactam were active in vitro against a susceptible clinical strain, and the combination was highly effective in the treatment of rat intra-abdominal abscesses. loss of expression of a 39-kda outer membrane protein resulted in at least a fourfold increase in th ... | 1993 | 8390809 |
| [some developmental features of escherichia coli mu phage in pseudomonas aeruginosa cells]. | in order to determine the replication-transposition (rt) efficiency of escherichia coli phage mu in pseudomonas aeruginosa cells, the change of mu dna copy number after transfer of p. aeruginosa (rp4::mu) from 42 (the condition of rp4::mu plasmid stability and low phage production level in p. aeruginosa) to 30 degrees c (the condition of rp4::mu plasmid instability and higher phage production level in p. aeruginosa) was analysed. it was shown that the temperature shift causes no increase in mu d ... | 1993 | 8370507 |
| [the effect of certain escherichia coli genes on the appearance of the tcs phenotype, conferred by plasmid rp4 with an integrated genome of the d3112 pseudomonas aeruginosa phage]. | the possibility of the sos system activation caused by introduction of a hybrid plasmid rp4::d3112 (where d3112 is a genome of the transposable phage of pseudomonas aeruginosa) into escherichia coli was examined. it has been shown previously that the presence of this plasmid confers to e. coli a so called tcs phenotype: e. coli (rp4::d3112) forms normal colonies and grows at 42 degrees c but does not divide and becomes filamentous at 30 degrees c, probably because of e. coli dna damages generate ... | 1993 | 8405972 |
| the mating pair formation system of plasmid rp4 defined by rsf1010 mobilization and donor-specific phage propagation. | transfer functions of the conjugative plasmid rp4 (incp alpha) are distributed among distinct regions of the genome, designated tra1 and tra2. by deletion analyses, we determined the limits of the tra1 region, essential for intraspecific escherichia coli matings. the tra1 core region encompasses approximately 5.8 kb, including the genes traf, -g, -h, -i, -j, and -k as well as the origin of transfer. the tram gene product, however, is not absolutely required for conjugation but significantly incr ... | 1993 | 8407818 |
| structure, function, and regulation of the kilb locus of promiscuous plasmid rk2. | the kil-kor regulon of the self-transmissible, broad-host-range plasmid rk2 is a unique network with eight coregulated operons. among the genes encoded by the kil-kor regulon are trfa, which encodes the replication initiator, and several kil loci (kila, kilb, kilc, and kile), each of which is lethal to the host cell in the absence of appropriate negative regulatory elements encoded by the kora, korb, korc, and kore determinants. we have proposed that the functions of the kil loci are related to ... | 1993 | 8468300 |
| trai, a luxi homologue, is responsible for production of conjugation factor, the ti plasmid n-acylhomoserine lactone autoinducer. | conjugal transfer of the nopaline-type agrobacterium ti plasmid ptic58 is regulated by a transcriptional activator, trar, and a diffusible signal molecule, conjugation factor (cf). cf is a member of a family of substituted homoserine lactones (hsls) that act as coinducers for regulating gene expression in diverse gram-negative bacteria by a mechanism called autoinduction. in vibrio fischeri hsl production is conferred by the luxi gene. homologues of this gene are responsible for hsl production b ... | 1994 | 8197112 |
| [the phenotype of rpi mutant of pseudomonas aeruginosa phage-transposon d3112 expressed in a heterologous escherichia coli host]. | a clone of escherichia coli ii-16 with unique properties was isolated upon incorporation of hybrid plasmid rp4::d3112 with an integrated genome of phage-transposon d3112 pseudomonas aeruginosa into e. coli c600 cells. the cells of this clone produce viable phage and are not sensitive to growth under low temperatures, which is characteristic of the majority of e. coli (rp4::d3112) clones with the genome of wild type phage. the clone e. coli ii-16 contains phage genome both in an integrated state ... | 1994 | 8188046 |
| plasmid and transposon transfer to thiobacillus ferrooxidans. | the broad-host-range incp plasmids rp4, r68.45, rp1::tn501, and pub307 were transferred to acidophilic, obligately chemolithotrophic thiobacillus ferrooxidans from escherichia coli by conjugation. a genetic marker of kanamycin resistance was expressed in t. ferrooxidans. plasmid rp4 was transferred back to e. coli from t. ferrooxidans. the broad-host-range incq vector pjrd215 was mobilized to t. ferrooxidans with the aid of plasmid rp4 integrated in the chromosome of e. coli sm10. pjrd215 was st ... | 1994 | 8188590 |
| escherichia coli f plasmid transfers to and replicates within legionella pneumophila: an alternative to using an rp4-based system for gene delivery. | derivatives of the self-transmissible f plasmid of escherichia coli can be introduced into legionella pneumophila by conjugation and maintained within only upon selection. in l. pneumophila. f-based replicons seem to exist as extrachromosomal elements since they were readily lost when f-containing l. pneumophila was grown on nonselective medium. the f-based plasmids were not self-transmissible in l. pneumophila. the mating defect may be due to an inability to form the f pilus since f-containing ... | 1994 | 7899513 |
| metabolic deprivation: a lead to containment in bacterial releases. | experiments were carried out in non-sterile soil, with or without several substrates (sucrose, citrate, lactose) as energy source, and with or without bacterial inoculates able or unable to utilize these substrates. the bacteria were enterobacter agglomerans, escherichia coli, pseudomonas aeruginosa or pseudomonas aureofaciens; they either did or did not contain plasmid rp4. it was found that sucrose is degraded by the indigenous microflora and/or free soil enzymes to give extracellular glucose ... | 1994 | 7921354 |
| essential motifs of relaxase (trai) and trag proteins involved in conjugative transfer of plasmid rp4. | two essential transfer genes of the conjugative plasmid rp4 were altered by site-directed mutagenesis: trag of the primase operon and trai of the relaxase operon. to evaluate effects on the transfer phenotype of the point mutations, we have reconstituted the rp4 transfer system by fusion of the transfer regions tra1 and tra2 to the small multicopy replicon cold. deletions in trag or trai served to determine the tra phenotype of mutant plasmids by trans complementation. two motifs of trag which a ... | 1994 | 8021214 |
| requirements for mobilization of plasmids rsf1010 and cole1 by the incw plasmid r388: trwb and rp4 trag are interchangeable. | mobilization of plasmid rsf1010 by the incw plasmid r388 requires the genes involved in w pilus synthesis plus trwb. trag of the incp plasmid rp4 can substitute for trwb in rsf1010 mobilization by r388 but not in self-transfer of r388. this result suggests a dual specificity of trwb-like proteins in conjugation. the same genetic requirements were found for r388 to mobilize the unrelated plasmid cole1. | 1994 | 8021231 |
| small mobilizable multi-purpose cloning vectors derived from the escherichia coli plasmids pk18 and pk19: selection of defined deletions in the chromosome of corynebacterium glutamicum. | here we describe small mobilizable vectors based on the escherichia coli plasmids pk18 and pk19. we combined the useful properties of the pk plasmids (e.g., multiple cloning site, lacz alpha fragment, sequencing with m13 primers) with the broad-host-range transfer machinery of plasmid rp4 and a modified sacb gene from bacillus subtilis. the new pk derivatives can be transferred by rp4-mediated conjugation into a wide range of gram- and gram+ bacteria, and should facilitate gene disruption and al ... | 1994 | 8045426 |
| analysis of the multimer resolution system encoded by the parcba operon of broad-host-range plasmid rp4. | the broad-host-range plasmid rp4 encodes a highly efficient partitioning function, termed par, that is capable of stabilizing plasmids in a variety of gram-negative bacteria independently of the nature of the replicon. the mechanism responsible for plasmid stabilization by this locus appears to be a complex system which includes a site-specific recombination system mediating resolution of plasmid multimers. in this report we present a detailed study on this multimer resolution system (mrs). the ... | 1994 | 8057833 |
| conjugal transfer of cosmid dna from escherichia coli to saccharopolyspora spinosa: effects of chromosomal insertions on macrolide a83543 production. | cosmid poj436, containing large inserts of saccharopolyspora spinosa (ss) dna, was transferred by conjugation from escherichia coli to ss an integrated into the chromosome, apparently by homologous recombination, at high frequencies (10(-5) to 10(-4) per recipient). transfer was mediated by the plasmid rp4 (rk2) transfer functions in e. coli, and the rk2 orit function located on poj436 [bierman et al., gene 116 (1992) 43-49]. poj436 lacking ss dna, or containing a small insert (approx. 2 kb) of ... | 1994 | 8063103 |
| concerted action of three distinct domains in the dna cleaving-joining reaction catalyzed by relaxase (trai) of conjugative plasmid rp4. | the trai protein of plasmid rp4 (incp alpha) catalyzes a site- and strand-specific cleaving-joining reaction on form i or single-stranded dna. thus, trai is one of the key components involved in the initiation and termination of horizontal dna transfer by bacterial conjugation. amino acid sequence comparison revealed three motifs in the trai sequence conserved in relaxases from different origins. site-directed mutagenesis of the trai structural gene and application of purified mutant trai protei ... | 1994 | 8300611 |
| promiscuous dna transfer system of agrobacterium tumefaciens: role of the virb operon in sex pilus assembly and synthesis. | conjugative transfer of dna that occurs between bacteria also operates between bacteria and higher organisms. the transfer of dna between gram-negative bacteria requires initial contact by a sex pilus followed by dna traversing four membranes (donor plus recipient) using a transmembrane pore. accumulating evidence suggests that transfer of the t-dna from agrobacterium tumefaciens to plants may also occur via a conjugative mechanism. the virb operon of the ti plasmid exhibits close homologies to ... | 1994 | 7914664 |
| the sequence of the mer operon of pmer327/419 and transposon ends of pmer327/419, 330 and 05. | three different, independently isolated mercury-resistance-conferring plasmids, pmer327/419, pmer330 and pmer05, from cultures originating from the river mersey (uk), contain identical regulatory merr genes and transposon ends. the mer determinant from pmer327/419 contains an additional potential orf (orf f) located between merp and mera when compared with the archetypal tn501. although these plasmids confer narrow-spectrum resistance (resistance to hg2+, but not organomercurials) their merr gen ... | 1994 | 8063107 |
| recombination of the bph (biphenyl) catabolic genes from plasmid pww100 and their deletion during growth on benzoate. | pseudomonas sp. strain cb406 was isolated from polychlorinated biphenyl-contaminated soil and harbors a nontransmissible plasmid, pww100, of approximately 200 kb which carries the genes required for biphenyl and 4-chlorobiphenyl catabolism. the catabolic phenotype was mobilized following the construction in vivo of a cointegrate plasmid containing functional upper and lower biphenyl operons inserted into the broad-host-range r plasmid rp4. the bph phenotype carried by pww100 was stable in nonsel ... | 1994 | 16349195 |
| exogenous isolation of mobilizing plasmids from polluted soils and sludges. | exogenous plasmid isolation was used to assess the presence of mobilizing plasmids in several soils and activated sludges. triparental matings were performed with escherichia coli (a member of the gamma subgroup of the proteobacteria) as the donor of an incq plasmid (pmol155, containing the heavy metal resistance genes czc: co, zn, and cd), alcaligenes eutrophus (a member of the beta subgroup of the proteobacteria) as the recipient, and indigenous microorganisms from soil and sludge samples as h ... | 1994 | 16349216 |
| site-specific mutations in the trai relaxase and upstream region of plasmid rp4. | the relaxase of rp4 nicks the double-stranded plasmid at the orit site and binds covalently to dna at the 5' end of the nick. the 80-kda relaxase (trai) is encoded on an operon with several overlapping open reading frames (orfs). the importance in conjugation of a short orf (trax) with a start site overlapping the 5' terminus of trai was investigated, as well as the effects of specific mutations in the relaxase. elimination of trax reduced the transfer efficiency by approximately 50% in several ... | 1995 | 8825378 |
| site-specific deletions of chromosomally located dna segments with the multimer resolution system of broad-host-range plasmid rp4. | the multimer resolution system (mrs) of the broad-host-range plasmid rp4 has been exploited to develop a general method that permits the precise excision of chromosomal segments in a variety of gram-negative bacteria. the procedure is based on the site-specific recombination between two directly repeated 140-bp resolution (res) sequences of rp4 effected by the plasmid-borne resolvase encoded by the para gene. the efficiency and accuracy of the mrs system to delete portions of chromosomal dna fla ... | 1995 | 7798149 |