| [expression of pseudomonas aeruginosa phage transposons in pseudomonas putida ppg1 cells. ii. zygotic induction--a necessary condition for the formation of defective lysogens]. | the transfer of hybrid plasmid rp4::pt (where pt is the genome of a transposable phage specific for pseudomonas aeruginosa) into recipient cells of p. putida strain ppg1 occurs with the same frequency as into p. aeruginosa, the homologous host for pt. approximately 1/3 of all ppg1 exconjugants carrying rp4 markers lost the capability to produce viable pt phage. in contrast, in a cross with homologous recipient p. aeruginosa all exconjugant clones contained nondefective prophages in the hybrid pl ... | 1985 | 3002910 |
| bacteriophage mu-mediated gene transposition and in vitro cloning of the enterochelin gene cluster of escherichia coli. | transposition of chromosomal genes using bacteriophage mu has been used to obtain a partial order of the nine closely linked genes of the enterochelin-dependent iron transport system of escherichia coli k-12. fragments of the ent gene cluster were transposed into the conjugative plasmid rp4 and were characterized by genetic complementation. the partial gene order (entd, fes), entf, fep, entc, ent(abeg)...lip was derived using six plasmids which carried overlapping parts of the cluster, and the f ... | 1980 | 6260579 |
| [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 |
| [hybrid plasmid pbs251 containing genes for n-alkane degradation]. | the strain of pseudomonas aeruginosa bs316 utilizing h-alkanes of the c6-c12 series (alk+) harbours the 96 md plasmid pbs250. the use of plasmid rp4 to mobilize alk+ markers in conjugal transfer to pseudomonas aeruginosa and pseudomonas putida has resulted in isolation of transconjugants resistant to antibiotics (due to genes coded by plasmid rp4) and capable of growth on h-alkanes. a transconjugant from this series harbours plasmid pbs251, a derivative of plasmid rp4 containing the genes for oc ... | 1985 | 3025683 |
| [plasmid recombination stimulated by restriction endonuclease ecori in vivo: formation of recombinant plasmids in reca+-cells of e. coli]. | the possible participation of restriction endonuclease ecori in recombination of compatible nonhomologous plasmids in e. coli cells has been studied. to study the process, plasmids rp4 and r245 have been transferred by conjugation into the recipient cells of e. coli harbouring one of isogenic plasmids, psa14 and psa25, different for the genes coding restriction endonuclease ecori. the genetic analysis of transconjugant phenotypes, coded by the plasmids, has permitted to register the recombinant ... | 1985 | 3025697 |
| isr1: an insertion element isolated from the soil bacterium rhizobium lupini. | the insertion element isr1 was isolated from the soil bacterium r. lupini. in this strain, isr1 shows a very strong affinity to plasmid rp4. it causes rp4 mutations at the strikingly high frequency of 10(-2) to 10(-1), either by the integration itself or by generating deletions. in e. coli, isr1 seems to be inactive. no evidence could be obtained for a promoter site on isr1 or for an isr1-encoded protein. our results indicate, however, an isr1-specific termination signal for either transcription ... | 1981 | 6271495 |
| [characteristics of reca-independent recombination of plasmids in e. coli cells producing restriction endonuclease ecori]. | the restriction endonuclease ecori dependent recombination of compatible plasmids has been studied in reca cells of escherichia coli. plasmid rp4 and the isogenic cole1 type plasmids psa14 or psa25, differing in restriction-modification rm ecori genes, have been used to study this type of recombination. ecori dependent recombination of plasmids is demonstrated in reca cells and, thus, is independent of general system of homologous recombination. the classes of recombinant plasmids isolated from ... | 1985 | 3025706 |
| [characteristics of derivatives of the plasmid rp4 in a broad range of hosts with altered properties of maintenance and inheritance]. | hydroxylamine-induced mutants of the plasmid ppd6 (8.4 kb) were isolated which are resistant to high doses of tetracycline. one of the plasmids studied--ppd21 is a multicopy mutant, another one, ppd12 is a dimeric form of the ppd6 plasmid. the ppd12 plasmid is very unstable, its derivative, ppd13 spontaneous mutant acquiring stability but not the ability to resolve dna multimeric forms into monomeric forms. multicopy bireplicon ppd619 plasmid was constructed by joining in vitro ppd6 and puc19 pl ... | 1986 | 3026896 |
| [structural-functional organization of r-plasmid pbs222 with a broad range of bacterial hosts]. | the broad host-range plasmid pbs222 is compatible with broad host-range plasmids of all known incompatibility groups and codes for tetracycline resistance. pbs222 is efficiently mobilized by inc p-1 plasmid rp4 and is also capable of conjugal transfer with low efficiency to different gramnegative microorganisms. the size of the plasmid (17.2 kb) has been determined and its physical map has been constructed. the plasmid harbours the unique sites for restriction endonucleases bglii, hindiii, hpai, ... | 1986 | 3027554 |
| 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 |
| 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 |
| 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 |
| [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 |
| [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 |
| the association behaviour of beta-lactamases. sedimentation equilibrium studies in ammonium sulphate solutions. | the beta-lactamases (ec 3.5.2.6) from tem plasmid rp4, bacillus licheniformis 749/c and enterobacter cloacae p99 were studied in solution over a wide concentration range by equilibrium sedimentation. though crystal symmetries indicate that all three enzymes are potentially dimeric in their crystal forms, in 50 mm-sodium cacodylate at ph 6.5 the enzymes show only a small tendency to associate, indicated by a weight-average mr (mw) at 3% (w/v) concentration about 9% greater than that of the monome ... | 1986 | 3492196 |
| high frequency mobilization of gram-negative bacterial replicons by the in vitro constructed tn5-mob transposon. | a dna fragment of the broad host range plasmid rp4 carrying the cis-acting dna recognition site for conjugative dna transfer between bacterial cells (mobsite) was cloned into the kanamycin-neomycin resistance transposon tn5. using conventional transposon mutagenesis techniques the new transposon, called tn5-mob, can easily be inserted into the host dna of gram-negative bacteria. a host replicon carrying tn5-mob is then mobilizable into any other gram-negative species if the transfer functions of ... | 1984 | 6094969 |
| [transposition of the phage d3112 genome in escherichia coli cells]. | it has been demonstrated that the genome of phage d3112 of preudomonas aeruginosa can be transposed into escherichia coli chromosome as a component of the hybrid plasmid rp4 tcrkms::d3112. also, transposition of d3112 from e. coli (d3112) chromosome into rp4 plasmid occurs. the phage stimulates the chromosome mobilizing activity of rp4 plasmid, similar to other transposons. e. coli (rp4::d3112) cells were previously shown to form no colonies at 30 degrees c. auxotrophic mutants and mutants incap ... | 1983 | 6317518 |
| molecular cloning and mapping of sphi restriction fragments of plasmid rp4. | a combined physical and functional map of plasmid rp4 is presented including the sites for 18 restriction endonucleases. several cleavage sites of sphi, bali, and apai are suitable for the dissection of the transfer gene regions. recombinant plasmids containing rp4 sphi fragments were constructed to assist in localizing sites relative to each other and to assign functions conferred by rp4 to the host. | 1983 | 6318250 |
| proteus mirabilis chromosome mobilization by plasmid d: a physical characterization. | plasmid d, a hybrid of plasmids p-lac and r1 drd19, mediates polarized chromosome mobilization from one origin in proteus mirabilis strain pm5006, while the parental plasmids neither individually nor combined mobilize this chromosome. to elucidate its acquired mobilizing ability plasmid d was characterized physically in relation to p-lac and r1 drd19. restriction patterns of these plasmids were compared and it was shown that d consists of p-lac and only the r-determinant (r-det) of r1 drd19. a m ... | 1984 | 6327883 |
| involvement of kil and kor genes in the phenotype of a host-range mutant of rp4. | plasmid prp761 is a derivative of the promiscuous plasmid rp4, which has a tn76 insert 1.8 kb from its ecori site within the trfb region (barth 1979). this mutation was pleiotropic, having three effects: the plasmid is unstably maintained in e. coli, it reduces the growth rate of its host and it has suffered a reduction in host-range. we show that prp761 has reduced expression from both its kora and korb genes and that tn76 has inserted between them. fragment exchange experiments showed that thi ... | 1984 | 6097793 |
| autoregulation of the tyrr gene. | strains of escherichia coli k-12 in which the transcription of lacz is initiated from the tyrr promoter have been constructed by use of the mu d (apr lac) phage of casadaban and cohen (proc. natl. acad. sci. u.s.a. 76:4530-4533, 1979). these strains have been used to examine the regulation of expression from the tyrr promoter, with the synthesis of beta-galactosidase used as an index of expression. the specific activity of beta-galactosidase fell to 51% upon introduction of lambda (tn10) tyrr+; ... | 1982 | 6120934 |
| replication defective rp4 plasmids recovered after chromosomal integration. | phh6000 is a composite replicon made by the in vitro ligation of the incp plasmid rp4 to a fragment of bacteriophage lambda capable of autonomous replication. derivatives were selected in which it had integrated into the escherichia coli chromosome by homologous recombination with the resident lambda prophage, and plasmids were subsequently regenerated from the integrated molecules. although of the same molecular size as phh6000, all had altered properties: those recovered from the chromosome of ... | 1984 | 6231650 |
| isolation of transposon tna from plasmid rp4 carrying two copies of this element. | employing heteroduplex and restriction analyses, two inverted copies of a 3.2.10(6) dalton transposable sequence, tna, were found in rp4::tna, a spontaneously arisen derivative of the plasmid rp4. integration of the second copy of tna causes loss of the conjugative properties of rp4. both tna sequences in rp4::tna were localized and found to have opposite orientations. the dna fragment corresponding to the individual transposon tna was isolated after the endonuclease s1 digestion of rp4::tna mol ... | 1980 | 6244209 |
| [effective method of transduction with virulent phage pf16 using specific mutants of pseudomonas putida ppg1]. | a procedure of simple selection of pseudomonas putida ppg1 mutants is described. the mutants can be used for transduction with virulent pf16 phage, giving reliable results. the frequency of transduction of chromosomal markers ilv and trp was 10(-6). also, transduction of plasmid rp4 with phage pf16 was shown with the frequency of 10(-7). | 1985 | 3926609 |
| [introduction of the hybrid plasmid rp4::d3112 into pseudomonas putida cells requires the presence of specific mutation in the phage genome]. | the wild type of d3112, a transposable phage of pseudomonas aeruginosa can not be introduced as a portion of the hybrid plasmid rp4::d3112 into pseudomonas putida cells. it is only possible when phage d3112 carries mutations designated lpc (lethal for p. putida and escherichia coli). analysis of heteroduplex molecules between dnas of phages d3112w+ and d3112lpc demonstrated the absence of nonhomology regions, which suggests that lpc is a point mutation. the lpc2 mutation was located within the i ... | 1984 | 6086454 |
| adenine + thymine content of different genes located on the broad host range plasmid rp4. | the genetic map of plasmid rp4 was correlated with its adenine+thymine (at) map. for this purpose, rp4 dna was digested with one or both of the restriction enzymes ecori and hindiii and the resulting linear rp4 molecules and fragments were partially denatured, examined in the electron microscope and their at maps were determined using a computer program. from these at maps the ecori and hindiii restriction sites were located on the at map of rp4. since the positions of these restriction sites on ... | 1980 | 6248619 |
| [properties of potential vectors--derivatives of the broad-host--range plasmid rp4]. | nonconjugative deletion and recombinant derivatives of the rp4 plasmid are constructed. the plasmids can be used as vectors because they have relatively small molecular weights, unique cleavage sites for enzymes ecori, xhoi, bamhi, psti, kpni, bglii, salgi and hindiii (the plasmids prp401 and prp417 having six of these sites), and easily tested phenotypes (tcr, apr and gal+). in addition, all of them retain the broad host range property. also, the plasmid prp420 is a multicopy derivative capable ... | 1984 | 6094306 |
| high frequency mobilization of the chromosome of escherichia coli by a mutant of plasmid rp4 temperature-sensitive for maintenance. | two mutants of plasmid rp4 temperature-sensitive for maintenance were isolated and one of them (pth 10) was extensively studied. cells carrying pth10 showed temperature-sensitive drug resistance from which we isolated a number of temperature-independent derivatives. almost all of them were hfrs donating chromosomal genes to recipient bidirectionally from different points of origin. the hfrs may be formed in two steps: (1) the transposon (tn 1) carried by pth 10 translocates into the host chromos ... | 1980 | 6255296 |
| 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 |
| transposition of tn 1 to the rhizobium meliloti genome. | a derivative of the incp1 plasmid rp4, carrying the thermoinducible prophage mucts62, was obtained in escherichia coli k12 j53 (rp4). it was impossible to maintain the hybrid plasmid rp4::mucts62 in rhizobium meliloti gr4. thus, it was used as a vehicle for introducing the ampicillin-resistant transposon tn1 into the r. meliloti genome. transposition of tn1 did not generate auxotrophic strains, suggesting that the insertion of tn1 into the r. meliloti genome was relatively specific. two chromoso ... | 1980 | 6258027 |
| naturally occurring plasmids exhibiting incompatibility with members of incompatibility groups i and p. | from a group of naturally occurring antibiotic resistance plasmids, a number of plasmids were identified which were incompatible with members of incompatibility group p and also incompatibility group i alpha or i gamma. these plasmids also exhibited strong entry exclusion with members of group p only and showed a host range which resembled that of plasmids of group i rather than those of group p. segregants of a number of these plasmids appeared to have lost some of the incompatability and/or su ... | 1980 | 6776095 |
| expression of e. coli genes carried by hybrids of plasmid rp4. | hybrids of the rp4 plasmid, containing bacteriophage mu and chromosomal genes of escherichia coli, were transferred into salmonella typhimurium, pseudomonas putida, pseudomonas aeruginosa and proteus mirabilis. the individual genes of the arginine, histidine, leucine and threonine operons were expressed in these microorganisms. | 1980 | 6777258 |
| [induction of transposon tn1 translocation in uv-irradiated escherichia coli cells]. | ampicillin transposon tn1 translocates from plasmid rp4 into e. coli chromosome with a frequency of about 3.10(-4) per cell. irradiation of bacteria with uv-light increases the frequency of translocation essentially. mutation in lexa gene controlling the expression of cell uv-inducible functions blocks the induction of transposon translocation. protein synthesis inhibitor--chloramphenicol and transcription inhibitor--rifampicin decrease the effect of uv-light on transposition process. a possible ... | 1981 | 6265313 |
| analysis of chromosome mobilization using hybrids between plasmid rp4 and a fragment of bacteriophage lambda carrying is1. | | 1981 | 6267631 |
| transposition of a dna fragment flanked by two inverted tn1 sequences. | the 32 md fragment (derived from plasmid rp4::tn1) carrying the kmr gene and flanked by two inverted tn1 elements is capable of reca-independent translocation to other plasmids. we designated this new transposon tn1755. in various crosses, frequencies of tn1755 transposition to plasmids co1b-r3, r15 and f'co1vbtrp varied from 2.5 to 90% of the frequencies of tn1 transposition. tn1755 can integrate into various sites of the recipient plasmids. we failed to observe transposition of another rp4::tn ... | 1981 | 6269963 |
| restriction mediated by pav2 affects the transfer of plasmids in acinetobacter calcoaceticus. | the naturally occurring plasmid pav2 restricts the entry of the p class plasmid rp4 and the w class plasmids r388 and s-a into acinetobacter calcoaceticus strain ebf65/65 from escherichia coli. the w class plasmids only transfer from e. coli into pav2-strains. plasmid rp4 is modified in the presence of pav2 such that it is no longer restricted on entry into pav2 recipients of strain ebf65/65. | 1980 | 7021765 |
| mutagenesis by insertion of drug resistance transposon tn7 into a vibrio species. | a halotolerant, collagenolytic strain of vibrio sp. was conjugated with an escherichia coli strain carrying plasmid rp4. the plasmid was transferred to and maintained in the vibrio and could be subsequently transferred in matings to suitably marked stains of the same species. after conjugation with an e. coli carrying the cointegrate plasmid rp4::mu cts61::tn7, vibrio transconjugants were selected that carried tn7 inserted into the bacterial chromosome. a large proportion of these transconjugant ... | 1981 | 6270064 |
| plasmid rp4 specifies a deoxyribonucleic acid primase involved in its conjugal transfer and maintenance. | we surveyed plasmids representative of most incompatibility groups for their conferred deoxyribonucleic acid (dna) primase activity. rp4 (incp) was one of the few with such activity although, unlike the derepressed incialpha plasmids (which also specify a primase), it did not suppress the dnag mutation. using deletion and tn7 derivatives of rp4, we located the presumed primase structural gene (pri) in the 37- to 42-kilobase region. tn7 insertions in the adjacent tra1 region also reduced or cause ... | 1981 | 6273381 |
| [migration of the ampicillin transposon in enteropathogenic escherichia]. | migration of tn 1 from plasmid rp4 into the chromosome of enteropathogenic escherichia (epe) of serogroups o124 and o111 was studied. e. coli k 12 lc 411 (rp4) was used as the donor. it was shown that the transposition rate markedly differed depending on the period of ;the cell isolation from tn 1 in the chromosome, i. e. during conjugation or after several subcultures of the transconjugants from the autonomic plasmid onto the selective media. during the conjugation process the migration rate of ... | 1981 | 6275775 |
| rna polymerase binding sites on the broad host range plasmid rp4. | binding sites of escherichia coli rna polymerase on rp4 plasmid dna were determined electron microscopically. comparison of the rna polymerase binding map and the genetic map of rp4 revealed several strong binding sites outside the well-known rp4 genes. rna polymerase binding sites for the three antibiotic resistance genes were also detected. two binding sites were observed for the tra-1 region, whereas the tra-2 and tra-3 regions showed no prominent affinity for rna polymerase. the genomic regi ... | 1981 | 6278054 |
| tn1 insertion mutagenesis in escherichia coli k-12 using a temperature-sensitive mutant of plasmid rp4. | a method for tn1 insertion mutagenesis in escherichia coli has been developed using pth10, a mutant plasmid of rp4 temperature-sensitive for maintenance. the mutagenesis involves three steps. firstly, from strains carrying pth10 showing resistance to the antibiotics kanamycin, tetracycline, and ampicillin at 30 degrees c but not at 42 degrees c, clones are isolated resistant to kanamycin at 42 degrees c. such temperature-independent, drug resistant clones probably carry pth10 integrated into the ... | 1981 | 6278248 |
| occurrence of transposable trimethoprim resistance in clinical isolates of escherichia coli devoid of self-transmissible resistance plasmids. | fifty trimethoprim-resistant clinical isolates of escherichia coli, devoid of self transmissible trimethoprim resistance plasmids, were examined for the presence of trimethoprim resistance transposons. trimethoprim resistance was mobilized from 12 strains by transposition onto plasmid rp4. the trimethoprim resistance transposons isolated comprised two groups: those with and without linked streptomycin resistance. | 1982 | 6280601 |
| tn292l, a transposon encoding fosfomycin resistance. | the determinant of resistance to fosfomycin of the serratia marcescens plasmid pou900 was transposed into the plasmid cole1 and into the plasmid rp4 in the absence of the reca function of the host. in each case, the acquisition of fosfomycin resistance was correlated with the presence of a discrete piece of dna, uniform in size and in restriction pattern, this new, 7.5-megadalton transposable element encoding resistance to fosfomycin has been called tn2921. a preliminary map of the transposon is ... | 1982 | 6282810 |
| symbiotic nitrogen fixation: molecular cloning of rhizobium genes involved in exopolysaccharide synthesis and effective nodulation. | a transposon (tn5)-induced mutant (strain anu437) of rhizobium trifolii was isolated in which no water-soluble exopolysaccharide (eps) could be detected. this mutant was also incapable of forming nitrogen-fixing root nodules on clover plants. molecular cloning has demonstrated that the tn5 transposon was responsible for both of these mutant phenotypes and that there is a direct correlation between eps synthesis in this bacterial strain and its ability to carry out symbiotic nitrogen fixation. in ... | 1982 | 6296257 |
| 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 |
| 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 |
| [range of the transmissivity of the genetic transfer factors pap38, pap39, pap41 and pap42]. | a study was made of the transmissivity range of the genetic transfer factors pap38, pap39, pap41 and pap42 identified in e. coli. it was demonstrated that these factors are not capable of transfer to the cells of p. putida, p. fluorescens, r. leguminosarum, a. lipoferum, a. tumefaciens. factor pap42 is mobilized to transfer to p. putida and r. leguminosarum with the aid of plasmid rp4. it is assumed that in the course of mobilization, the cointegrative structures are formed between plasmids pap4 ... | 1983 | 6299434 |
| [transfer of plasmid rp4 into some phytopathogenic bacteria and its relation to their virulence]. | plasmid rp4 were transferred from escherichia coli into pseudomonas solanacerum, xanthomonas campestris pv. oryzae, x. campestris pv. campestris, and x. campestris pv. citri at the frequencies of 1.8 x 10(-6), 2.8 x 10(-6), 1.4 x 10(-2) and 2.0 x 10(-3), respectively. the frequencies of transfer depended on bacterial species and conjugation conditions. treatment of bromide at the concentration of 2 micrograms/ml and acridine orange at 100 micrograms/ml for 32 hrs the plasmid rp4 could be cured f ... | 1983 | 6342991 |
| 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 |
| plasmid rp4 encodes two forms of a dna primase. | the pri gene locus of the conjugative broad host range plasmid rp4 maps between coordinates 40.3 and 43.5 and encodes two antigenically related forms of a dna primase with a molecular mass of 118 and 80 kda (kilodalton). genesis of these two products has been examined using pri+-recombinant plasmids. as shown by deletion analysis, the primase polypeptides are tow separate translation products which arise from an in-phase overlapping gene arrangement. it is suggested that transcription of a set o ... | 1984 | 6374382 |
| 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 |
| [selection, analysis and mapping of mutations in the gene for resistance to kanamycin in plasmid rp4]. | we have tested possibilities of escherichia coli strains dependent on drugs streptomycin and paromomycin for selection of spontaneous mutations in the rp4 kan gene specifying resistance to aminoglycosids--kanamycin, neomycin and paromycin. a set of kan gene mutations were obtained, classified ad mapped. | 1984 | 6389260 |
| genetic manipulation of the restricted facultative methylotroph hyphomicrobium x by the r-plasmid-mediated introduction of the escherichia coli pdh genes. | the inability of hyphomicrobium x to grow on compounds such as pyruvate and succinate is most likely due to the absence of a functional pyruvate dehydrogenase (pdh) complex. further support for this was sought by studying the effect of the introduction of the escherichia coli pdh genes in hyphomicrobium x on the pattern of substrate utilization by the latter organism. these genes were cloned by in vivo techniques using the broad-host range conjugative plasmid rp4::mucts. plasmid rp4 derivatives ... | 1984 | 6393893 |
| [changes in the nature of the cell growth of pseudomonas aeruginosa pao from the conjugative introduction of plasmid rp4]. | conjugative transfer of rp4 plasmid into pseudomonas aeruginosa pao at 30 degrees c results in inhibition of growth of plasmid-containing cells. no inhibition of growth of exconjugants takes place under special conditions (usage of minimal m9 medium or incubation at 42 degrees c) and when cells have specific mutations. these mutations were designated as rpm (rp4 maintenance). some of them render cells resistance to temperate phages of p. aeruginosa. the frequency of transfer of rp4 into pao1rpm, ... | 1983 | 6414887 |
| 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 |
| 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 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 |
| [use of deletion mutants of plasmid rp4::d3112 for the genetic analysis of pseudomonas aeruginosa bacteriophage d3112]. | the hybrid plasmid rp4::d3112 becomes unstable in escherichia coli k-12 cells under certain growth conditions. the deletion mutants of this plasmid are formed at a high frequency. all the deletions selected have a specific feature: they start in the left end, at the point of joining of plasmid and phage dna, and remove different portions of the phage genome. the deletion mutants have been used for genetic mapping of d3112. we have localized the repressor gene ci (0-1.3 kb), 3 early genes (1.3-14 ... | 1983 | 6418616 |
| [expression of the resistance genes of plasmid rp4 in escherichia coli cells grown by continuous cultivation]. | the resistance to tetracycline decreased in escherichia coli c600 cells containing plasmid rp4 and grown under the conditions of continuous cultivation. the population of cells containing plasmid rp4 is heterogeneous in the trait of tetracycline resistance, and most cells cannot grow in a selective medium with tetracycline at a concentration of 20 micrograms/ml. the decreased resistance to tetracycline was most pronounced for a glucose-limited chemostat culture and also in the presence of two pl ... | 1984 | 6429491 |
| complementation analysis of the aliphatic amidase genes of pseudomonas aeruginosa. | a plasmid, pcl34, capable of autonomous replication in escherichia coli and pseudomonas aeruginosa has been constructed which carries the promoter and structural gene (amie) for p. aeruginosa amidase, but not the regulator gene (amir). plasmid pcl34 has been mobilized from e. coli to p. aeruginosa using the broad host range plasmid rp4. complementation studies were performed in p. aeruginosa strains carrying various amidase mutations. measurements of amidase activity in the recipients under indu ... | 1984 | 6440948 |
| [effectiveness of plasmid rp4 mobilization of the bacterial chromosome in escherichia coli strains lysogenic for phages mu and lambda]. | the effect of phage lambda on mobilization of escherichia coli chromosome mediated by the mu phage and rp4 plasmid has been studied. the efficiency of bacterial chromosome mobilization is an order of magnitude lower than that in the control strain, monolysogenic for phage mu provided a termoinducible prophage lambda is located separately from mu. this efficiency is an order of magnitude higher in comparison with the control strain in case prophage is incorporated in the mu-lambda-mu structure an ... | 1981 | 6459264 |
| [features of incompatibility expressed by 1- and 2-replicon deletion derivatives of plasmid rp4]. | | 1982 | 6754529 |
| [integration of the genome of the mu-like pseudomonas aeruginosa bacteriophage d3112 into plasmid rp4 and its hybrid plasmid transfer into pseudomonas putida and escherichia coli c600 bacteria]. | the genome of a mu-like bacteriophage d3112 specific for pseudomonas aeruginosa was integrated in vivo into the rp4 plasmid. the fact of integration has been proved by two experiments: 1. the loss of rp4 plasmid is accompanied by loss of d3112 prophage; 2. transfer of the plasmid by conjugation from pseudomonas aeruginosa into bacteria of other species - p. putida pgg1 or escherichia coli c600 leads to the occurrence of clones of these species which liberate phage capable of growing on the lawn ... | 1982 | 6799358 |
| [nature of the genetic control of antibiotic resistance in a pseudomonas aeruginosa bs205 strain]. | the clinical strain bs205 of p. aeruginosa is characterized by a high level of resistance to streptomycin, kanamycin, chloramphenicol, sulfanilamide and mercuric chloride. these markers can be transferred to p. aeruginosa pao by means of transduction with phage f116l or mobilization with plasmid rp4. in the same way as in the initial strain of p. aeruginosa bs205 no plasmid dna is detected in transducers or transconjugants. after transference to the strains of the transducers or transconjugants ... | 1982 | 6816141 |
| integrative compatibility: stable coexistence of chromosomally integrated and autonomous derivatives of plasmid rp4. | p group plasmid rp4 lambda att has a novel feature. its incompatibility function is phenotypically switched off when it integrates into the bacterial chromosome. | 1980 | 6991474 |
| [mobilization of vibrio cholerae chromosomal genes by plasmid rp4::mu cts62]. | the rp4::mu cts62 plasmid was constructed in escherichia coli cells and subsequently transferred by conjugation into the cells of vibrio cholerae. this plasmid had been shown to mobilize chromosomal genes of v. cholerae during intrageneric matings. the frequency of mobilization is higher in matings at 37 degrees c, the temperature which is semipermissive for temperature sensitive mu cts62 phage. this is only true for strains harbouring rp4::mu cts62, but not for strains containing the rp4 plasmi ... | 1982 | 7037543 |
| 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 |
| the orientation of transfer of the plasmid rp4. | | 1982 | 7040167 |
| comparison of kinetics of active tetracycline uptake and active tetracycline efflux in sensitive and plasmid rp4-containing pseudomonas putida. | membrane vesicles prepared from tetracycline-sensitive cells of pseudomonas putida took up tetracycline by an active transport system with an apparent km of 2.5 mm and a vmax of 50 nmol min-1 mg protein-1. in contrast, resistance determinant rp4-containing p. putida had an active high-affinity efflux system for tetracycline with a km of 2.0 to 3.54 microm and a vmax of 0.15 nmol min-1 mg protein-1. thus, the efflux system of tetracycline-resistant p. putida(rp4) had an average of 1,000-fold grea ... | 1982 | 7118827 |
| new mini-tn5 derivatives for insertion mutagenesis and genetic engineering in gram-negative bacteria. | five mini-tn5 derivatives encoding resistance to km, cm, gm, tc, and sm, coupled with the polylinker of the pbluescriptii plasmid, were constructed. these derivatives are carried by an ampicillin-resistant plasmid that has a conditional origin of replication from plasmid r6k and origin of conjugal transfer from the broad host range plasmid rp4. the new vectors are smaller than those previously described and possess numerous unique restriction sites inside the minitransposons for gene cloning in ... | 1995 | 7497352 |
| the use of two-dimensional gradient plates to investigate the range of conditions under which conjugal plasmid transfer occurs. | gel-stabilized two-dimensional gradient plates were used to study the effects of ph, salt concentration and temperature on the conjugal transfer of plasmid rp4 between strains of escherichia coli and pseudomonas putida. the combinations of ph and salt concentration that permitted conjugation were mapped as a two-dimensional growth area occupied by transconjugants following conjugation. this conjugation domain was less extensive than the areas that supported growth of the parental strains, and sh ... | 1995 | 7582032 |
| positive r plasmid mutator effect on chromosomal mutation to nalidixic acid resistance in nalidixic acid-exposed cultures of escherichia coli. | mutation frequencies to nalidixic acid resistance (15 mg/l in nutrient agar) were determined for derivatives of escherichia coli ab1157 carrying the mutator plasmids r46, r391 or pyd1, or the non-mutator plasmid rp4. frequencies of mutation remained constant in cultures of ab1157(r46) growing exponentially in drug-free broth, at a level about 12-fold higher than in the strain without plasmid. mutation frequencies in cultures of strains ab1157(r391) and ab1157(pyd1) were about three times greater ... | 1995 | 7592173 |
| 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 |
| transposition of dna fragments flanked by two inverted tn1 sequences: translocation of the plasmid rp4::tn1 region harboring the tcr marker. | we have demonstrated the possibility of transposition of the plasmid rp4::tn1 fragment (21.2 kb) carrying the tetracycline resistance (tcr) gene and flanked by two tn1 copies. the new transposon, designated tn1756, bears lethal genes that kill host cells. therefore, its transposition can only be revealed in the presence of lethality-compensating helper regions of the plasmid rp4. thus, rp4::tn1 consists of two transposons, tn1755 (tn1-kmr-tn1) and tn1756 (tn1-tcr-tn1), sharing the tn1 sequences. ... | 1983 | 6307824 |
| absence of cis-acting transposition immunity with tn7. | it is possible in two steps to insert into the plasmid rp4 two copies of the transposon tn7. this was demonstrated using a wild-type tn7 in the first step, and a tn7 derivative (carrying an additional marker), in the second step. the two successive transpositions occurred with the same polarity and frequency. the genetic structures of the resulting plasmids, predicted from the phenotypes of the bacterial host, were confirmed by direct analysis of the plasmid dnas. thus, the phenomenon of cis-act ... | 1983 | 6312476 |
| 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 |
| 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 |
| 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 |
| rp4::mu3a-mediated in vivo cloning and transfer of a chlorobiphenyl catabolic pathway. | chromosomal dna fragments encoding the ability to utilize biphenyl as sole carbon source (bph+) were mobilized by means of plasmid rp4::mu3a from strain jb1 (tentatively identified as burkholderia sp.) to alcaligenes eutrophus ch34 at a frequency of 10(-3) per transferred plasmid. the mobilized dna integrated into the recipient chromosome or was recovered as catabolic prime plasmids. three bph+ prime plasmids were transferred from a. eutrophus to escherichia coli and back to a. eutrophus without ... | 1996 | 8969525 |
| 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 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 |
| biological activity of new aza analogues of quinolones. | a series of novel derivatives of 4h-pyrido[1,2-]pyrimidine, 1,4-dihydro-4-oxo-1,5-naphthyridine and 1,4-dihydro-4-oxo-1,6-naphthyridine were prepared and their biological activity was compared with that of nalidixic acid. the in vitro antibacterial activity of the tested compounds was lower than that of nalidixic acid except for two agents, 1b and 2c, with a higher activity against enterococcus faecalis. the compounds were tested for their ability to cure four plasmids from two species of entero ... | 1997 | 9246761 |
| 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 |
| 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 |
| 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 |
| 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 |
| [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 |
| 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 |
| ptn5cat: a tn5-derived genetic element to facilitate insertion mutagenesis, promoter probing, physical mapping, cloning, and marker exchange in phytopathogenic and other gram-negative bacteria. | a tn5-derived mobile element has been constructed to identify genes and promoters related to pathogenesis and virulence in pseudomonas syringae pv. phaseolicola. to enhance the rate of mutation this tn5 derivative was constructed carrying a mutant transposase which was placed in cis to the transposable element, but just outside the inverted repeats, therefore eliminating secondary transposition and increasing the stability of the insertion. the new element also contains a promoterless cat (chlor ... | 1998 | 9571137 |
| [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 |
| 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 |
| distribution of restriction enzyme recognition sequences on broad host range plasmid rp4: molecular and evolutionary implications. | incp alpha plasmids, exemplified by rp4, are remarkable for their broad host range. they contain strikingly few cleavage sites for many commonly used type ii restriction enzymes but an overabundance of sites for certain enzymes that target g + c-rich sequences. to identify factors responsible for these distributions, the recently compiled nucleotide sequence of rp4 was analysed to determine the frequency of tetra- and hexanucleotide motifs in the 49 kb plasmid backbone. this is defined as the se ... | 1996 | 8642602 |
| bacterial conjugation mediated by plasmid rp4: rsf1010 mobilization, donor-specific phage propagation, and pilus production require the same tra2 core components of a proposed dna transport complex. | dna transfer by bacterial conjugation requires a mating pair formation (mpf) system that specifies functions for establishing the physical contact between the donor and the recipient cell and for dna transport across membranes. plasmid rp4 (incp alpha) contains two transfer regions designated tra1 and tra2, both of which contribute to mpf. twelve components are essential for mpf, traf of tra1 and 11 tra2 proteins, trbb, -c, -d, -e, -f, -g, -h, -i, -j, -k, and -l. the phenotype of defined mutants ... | 1995 | 7642506 |
| 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 |