| tn402: a new transposable element determining trimethoprim resistance that inserts in bacteriophage lambda. | we have found that the trimethoprim resistance determinant of the incp plasmid r751 (jacob et al., 1977; jobanputra and datta, 1974) transposes to bacteriophage lambda. we call this transposable element tn402. | 1977 | 321437 |
| transposition of tn4351 in porphyromonas gingivalis. | genetic analysis of porphyromonas gingivalis, an obligately anaerobic gram-negative bacterium, has been hindered by the apparent lack of naturally occurring bacteriophages, transposable elements, and plasmids. plasmid r751::*omega 4 has previously been used as a suicide vector to demonstrate transposition of tn4351 in b. uniformis. the erythromycin resistance gene on tn4351 functions in bacteroides and porphyromonas. erythromycin-resistant transconjugants were obtained at a mean frequency of 1.6 ... | 1992 | 1325062 |
| conjugal transfer of antibiotic resistance factors in bacteroides fragilis: the btga and btgb genes of plasmid pbftm10 are required for its transfer from bacteroides fragilis and for its mobilization by incp beta plasmid r751 in escherichia coli. | transferable plasmids play an important role in the dissemination of clindamycin-erythromycin resistance in bacteroides fragilis. we previously described the isolation and properties of pbftm10, a 14.9-kb clnr transfer factor from b. fragilis tmp10. we also reported the isolation of a transfer-deficient deletion derivative of pbftm10 contained in the b. fragilis-escherichia coli shuttle vector pgat400. in the present study we used pgat400 and a similar shuttle vector, pgat550, to characterize an ... | 1991 | 1657890 |
| 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 |
| plasmids of pseudomonas cepacia strains of diverse origins. | thirty-seven strains of pseudomonas cepacia from clinical, pharmaceutical-industrial, and environmental origins were analyzed for the presence of plasmid dna by a modification of the rapid alkaline extraction method of birnboim (h. c. birnboim, methods enzymol. 100:243-255, 1983). plasmids were present in 31 strains (84%) from all sources, with no one source showing less than 75% plasmid carriage among its strains. the plasmid profiles indicated that the presence of large plasmids (146 to 222 kb ... | 1991 | 1722661 |
| conjugal transfer of a shuttle vector from the human colonic anaerobe bacteroides uniformis to the ruminal anaerobe prevotella (bacteroides) ruminicola b(1)4. | prevotella ruminicola (formerly bacteroides ruminicola) is an anaerobic, gram-negative, polysaccharide-degrading bacterium which is found in the rumina of cattle. since p. ruminicola is thought to make an important contribution to digestion of plant material in rumina, the ability to alter this strain genetically might help improve the efficiency of rumen fermentation. however, previously there has been no way to introduce foreign dna into p. ruminicola strains. in this study we transferred a sh ... | 1991 | 1768083 |
| gene organization and nucleotide sequence of the primase region of incp plasmids rp4 and r751. | the primase genes of rp4 are part of the primase operon located within the tra1 region of this conjugative plasmid. the operon contains a total of seven transfer genes four of which (traa, b, c, d) are described here. determination of the nucleotide sequence of the primase region confirmed the existence of an overlapping gene arrangement at the dna primase locus (trac) with in-phase translational initiation signals. the trac gene encodes two acidic and hydrophilic polypeptide chains of 1061 (tra ... | 1991 | 1818755 |
| sequence identity in the nick regions of incp plasmid transfer origins and t-dna borders of agrobacterium ti plasmids. | the incp antibiotic-resistance plasmids transfer to a broad range of bacterial species. the rk2 origin of dna transfer (orit) consists of a 250-base-pair segment including the single-stranded cleavage site (nic) needed to generate the dna strand believed to be transferred. deletion derivatives and a bank of hydroxylamine-generated orit mutants were screened for loss of transferability. dna regions flanking both sides of nic are required for optimal transfer of the orit clone. of the chemically i ... | 1991 | 1996345 |
| 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 |
| mutagenesis of the tra1 core region of rk2 by using tn5: identification of plasmid-specific transfer genes. | the conjugation system of the incp alpha plasmid rk2/rp4 is encoded by transfer regions designated tra1, tra2, and tra3. the tra1 core region, cloned on plasmid pdg4 delta 22, consists of the origin of transfer (orit) and 2.6 kilobases of flanking dna providing incp alpha plasmid-specific functions that allow pdg4 delta 22 to be mobilized by the heterologous incp beta plasmid r751. tn5 insertions in pdg4 delta 22 define a minimal 2.2-kilobase region required for plasmid-specific transfer of orit ... | 1989 | 2544570 |
| site-specific recombination at orit of plasmid r1162 in the absence of conjugative transfer. | r1162 is efficiently comobilized during conjugative transfer of the self-transmissible plasmid r751. bacteriophage m13 derivatives that contain two directly repeated copies of orit, the site on r1162 dna required in cis for mobilization, were constructed. phage dna molecules underwent recombination during infection of escherichia coli, with the product retaining a single functional copy of orit. recombination was strand specific and depended on r1162 gene products involved in mobilization, but d ... | 1989 | 2644236 |
| in vivo formation of gene fusions in pseudomonas putida and construction of versatile broad-host-range vectors for direct subcloning of mu d1 and mu d2 fusions. | the mu d1 and mu d2 prophages were integrated into the conjugative broad-host-range plasmid r751. the two plasmids were then transferred into pseudomonas putida, and derivatives carrying intact mu prophages were recovered. after induction of mu at 42 degrees c, both operon and gene fusions were observed on 5-bromo-4-chloro-3-indolyl-beta-d-galactopyranoside (x-gal) plates. broad-host-range vectors were constructed which allow direct cloning of both operon or gene fusions and their analysis in es ... | 1987 | 2821901 |
| transposon insertion mutagenesis of pseudomonas aeruginosa with a tn5 derivative: application to physical mapping of the arc gene cluster. | for insertional mutagenesis of pseudomonas aeruginosa, a derivative of the kanamycin-resistance (kmr) transposon tn5 was constructed (tn5-751) that carried the trimethoprim-resistance (tpr) determinant from plasmid r751 as an additional marker. double selection for kmr and tpr avoided the isolation of spontaneous aminoglycoside-resistant mutants which occur at high frequencies in p. aeruginosa. as a delivery system for the recombinant transposon, plasmid pme305, a derivative of the broad-host-ra ... | 1985 | 2989092 |
| tn4351 transposes in bacteroides spp. and mediates the integration of plasmid r751 into the bacteroides chromosome. | the gene for resistance to erythromycin and clindamycin, which is carried on the conjugative bacteroides plasmid, pbf4, has been shown previously to be part of an element (tn4351) that transposes in escherichia coli. we have now introduced tn4351 into bacteroides uniformis 0061 on the following two suicide vectors: (i) the broad-host-range incp plasmid r751 (r751::tn4351) and (ii) pss-2, a chimeric plasmid which contains 33 kilobases of pbf4 (including tn4351) cloned into the incq plasmid rsf101 ... | 1986 | 3005243 |
| use of targeted insertional mutagenesis to determine whether chondroitin lyase ii is essential for chondroitin sulfate utilization by bacteroides thetaiotaomicron. | bacteroides thetaiotaomicron produces two inducible chondroitin lyases (i and ii) when it is grown on chondroitin sulfate. both enzymes have very similar biochemical properties. to determine whether both enzymes are required for growth on chondroitin sulfate, we constructed a bacteroides suicide vector, pe3-1, and used it to create an insertional mutation that interrupts the chondroitin lyase ii gene of bacteroides thetaiotaomicron. pe3-1 contains a 4.4-kilobase cryptic b. eggerthii plasmid (pb8 ... | 1986 | 3011755 |
| mode of replicon fusion mediated by the duplicated insertion sequence is21 in escherichia coli. | the insertion sequence is21 (2.1 kb) originating from the broad-host-range incp plasmid r68 transposes infrequently; by contrast, the is21 tandem repeat found on the derivative r68.45 is highly active in transpositional mobilization of other replicons in a variety of gram-negative bacteria. the mobilized plasmids are joined to r68.45 by single is21 copies in direct orientation. the formation of is21 tandem duplications was observed in cointegrates between r68.45 and pbr325::is21 and also in an r ... | 1987 | 3034717 |
| facilitated transfer of incp beta r751 derivatives from the chromosome of bacteroides uniformis to escherichia coli recipients by a conjugative bacteroides tetracycline resistance element. | the broad-host-range incp beta plasmid r751 can mobilize itself from escherichia coli to bacteroides spp, but it is not maintained in bacteroides spp. if r751 carries the bacteroides transposon tn4351, it can be integrated into the bacteroides chromosome. previously we showed that r751, integrated in the chromosome of bacteroides uniformis, cannot mobilize itself out of b. uniformis into e. coli or isogenic b. uniformis strains. in this report, we showed that if the bacteroides conjugative tetra ... | 1987 | 3036772 |
| [use of the plasmid r89s replicon for constructing integration vectors]. | it has been shown that the plasmid r89s derivatives can be used as integrative vectors for bacteria in which the plasmid is unable to replicate autonomously. the chromosomal and plasmid fragments of phototrophic bacterium rhodobacter sphaeroides have been cloned in plasmid pvz365, a smrkmr-derivative of r89s. the obtained recombinant plasmids were mobilized into r. sphaeroides cells by the i pcp-group conjugative plasmid r751. the frequencies of the smr-transconjugants formation are 3.7.10(-5) t ... | 1987 | 3499569 |
| regions in bacteroides plasmids pbftm10 and pb8-51 that allow escherichia coli-bacteroides shuttle vectors to be mobilized by incp plasmids and by a conjugative bacteroides tetracycline resistance element. | bacteroides-escherichia coli shuttle vectors containing a nonmobilizable pbr322 derivative and either pbftm10 (pdp1, pcg30) or pb8-51 (peg920) were mobilized by incp plasmid r751 or prk231 (an ampicillin-sensitive derivative of rk2) between e. coli strains and from e. coli to bacteroides recipients. inci alpha r64 drd-ll transferred these vectors 1,000 times less efficiently than did the incp plasmids. pdp1, pcg30, and peg920 could be mobilized from b. uniformis donors to both e. coli and bacter ... | 1986 | 3519587 |
| nucleotide sequence analysis of the trimethoprim resistant dihydrofolate reductase encoded by r plasmid r751. | | 1986 | 3526286 |
| comparison of the nucleotide sequences of the vegetative replication origins of broad host range incp plasmids r751 and rk2 reveals conserved features of probable functional importance. | an 864 bp ecori fragment carrying orivr751, the vegetative replication origin of broad host range incp plasmid r751, was cloned and sequenced. only the trfa gene of the incp plasmid rk2 was required in trans for the function of orivr751. the sequence of orivr751 showed 65% overall homology to that of orivrk2 determined previously. highly conserved regions of probable functional importance were apparent, including two sets of direct repeats postulated to be interaction sites for the trfa protein( ... | 1985 | 4000925 |
| genetic organization of the broad-host-range incp-1 plasmid r751. | we have identified regions encoding conjugal transfer, plasmid maintenance, and trimethoprim resistance on the incp-1 plasmid r751 by complementation tests with cloned deoxyribonucleic acid fragments and self-replicating derivatives constructed in vitro. the genes for replication and transfer show a scattered organization similar to that previously determined for rk2, another incp-1 plasmid. derivatives of rk2 are able to complement r751 derivatives defective in these functions. restriction enzy ... | 1980 | 6251029 |
| properties of r1162, a broad-host-range, high-copy-number plasmid. | regions of plasmid dna encoding characteristic properties of the incq (p-4) group plasmid r1162 were identified by mutagenesis and in vitro cloning. coding sequences sufficient for expression of incompatibility and efficient conjugal mobilization by plasmid r751 were found to be linked to the origin of dna replication. in contrast, there was a region remote from the origin, and active in trans, that was required for plasmid maintenance. a derivative that was temperature sensitive for stability w ... | 1982 | 6279561 |
| plasmid rearrangements in the photosynthetic bacterium rhodopseudomonas sphaeroides. | mu d1(ap lac) was introduced into the photosynthetic bacterium rhodopseudomonas sphaeroides 2.4.1. via the r-plasmid r751 in an attempt to isolate fusion derivatives involving photosynthetic operons. the selection system is potentially very powerful since r. sphaeroides is normally lac negative. among the exconjugants, photosynthesis-deficient mutants were recovered, some of which had elevated beta-galactosidase levels. among the mutants examined, beta-galactosidase expression was linked exclusi ... | 1984 | 6327628 |
| evolution of the kora-oriv segment of promiscuous incp plasmids. | plasmids belonging to escherichia coli incompatibility group p are of particular interest because they can transfer between, and be stably maintained in, almost all gram-negative bacterial species. the segment of the incp alpha plasmid genome between the key regulatory gene kora and the vegetative replication origin, oriv, encodes a series of operons co-regulated with replication and transfer functions by the kora protein. to determine which of these genes are likely to have an important role in ... | 1995 | 7773415 |
| retrotransfer of incp plasmid r751 from escherichia coli maxicells: evidence for the genetic sufficiency of self-transferable plasmids for bacterial conjugation. | gene transfer between organisms is a prime contributor to evolution. bacterial conjugation is probably the most important mechanism by which genes are spread among prokaryotes and perhaps also contributes to eukaryotic evolution. conjugation is mediated by plasmids. the mechanism of conjugation remains ill-understood despite progress in the identification, mapping and sequencing of genes required for plasmid transmission. all conjugation-specific genes (those required only for dna transfer and e ... | 1993 | 7968518 |
| complete nucleotide sequence of birmingham incp alpha plasmids. compilation and comparative analysis. | the incp alpha promiscuous plasmid (r18, r68, rk2, rp1 and rp4) comprises 60,099 bp of nucleotide sequence, encoding at least 74 genes. about 40 kb of the genome, designated the incp core and including all essential replication and transfer functions, can be aligned with equivalent sequences in the incp beta plasmid r751. the compiled incp alpha sequence revealed several previously unidentified reading frames that are potential genes. incp alpha plasmids carry genetic information very efficientl ... | 1994 | 8014987 |
| transposon tn5090 of plasmid r751, which carries an integron, is related to tn7, mu, and the retroelements. | integrons confer on bacterial plasmids a capability of taking up antibiotic resistance genes by integrase-mediated recombination. we show here that integrons are situated on genetic elements flanked by 25-bp inverted repeats. the element carrying the integron of r751 has three segments conserved with similar elements in tn21 and tn5086. several characteristics suggest that this element is a transposon, which we call tn5090. tn5090 was shown to contain an operon with three open reading frames, of ... | 1994 | 8195081 |
| conjugative transfer and in vitro/in vivo stability of the broad-host-range incp r751 plasmid in brucella spp. | escherichia coli strain k12 bm14, carrying plasmid r751 (51.4 kb; tpr, tra+, incp), was used as donor in matings with reference strains of the six brucella nomenspecies, not known so far to harbor naturally occurring plasmids. r751 was easily transferred to and between brucella spp., at frequencies ranging between 10(-1) and 10(-4). all brucella transconjugants stably maintained plasmid r751 both in vitro and in vivo in our experimental conditions. no genetic modification of the plasmid during a ... | 1993 | 8469720 |
| the 3' conserved segment of integrons contains a gene associated with multidrug resistance to antiseptics and disinfectants. | nucleotide sequence analysis of orf1 from the integron on the broad-host-range plasmid r751 revealed that the first 94 of 110 codons of orf1 from r751 are identical to orf4, an open reading frame from the 3' conserved segment of other integrons found in gram-negative bacteria, after which point they diverged completely. the predicted products of both orf1 and orf4 share homology with the multidrug exporter qacc. phenotypic analysis revealed that orf1 specifies a resistance profile to antiseptics ... | 1993 | 8494372 |
| characterization of transposon tn5469 from the cyanobacterium fremyella diplosiphon. | a transposon, designated tn5469, was isolated from mutant strain fdr1 of the filamentous cyanobacterium fremyella diplosiphon following its insertion into the rcac gene. tn5469 is a 4,904-bp noncomposite transposon with 25-bp near-perfect terminal inverted repeats and has three tandemly arranged, slightly overlapping potential open reading frames (orfs) encoding proteins of 104.6 kda (909 residues), 42.5 kda (375 residues), and 31.9 kda (272 residues). insertion of tn5469 into the rcac gene in s ... | 1995 | 8522506 |
| development of techniques for the genetic manipulation of the gliding bacterium cytophaga johnsonae. | cytophaga johnsonae displays many features that make it an excellent model of bacterial gliding motility. unfortunately, genetic analyses of c. johnsonae, or any related gliding bacteria, were not possible because of a complete lack of selectable markers, cloning vectors, transposons, and convenient methods of gene transfer. as a first step toward a molecular analysis of gliding motility of c. johnsonae, we developed these genetic techniques and tools. common broad-host-range plasmids and transp ... | 1996 | 8550486 |
| localized denaturation of orit dna within relaxosomes of the broad-host-range plasmid r1162. | the broad-host-range, multicopy plasmid r1162 is efficiently mobilized during conjugation by the self-transmissible plasmid r751. the relaxosome, a complex of plasmid dna and r1162-encoded proteins, forms at the origin of transfer (orit) and is required for mobilization. transfer is initiated by strand- and site-specific nicking of the dna within this structure. we show by probing with potassium permanganate that orit dna is locally melted within the relaxosome, in the region from the inverted r ... | 1995 | 8801426 |
| conservation of the genetic switch between replication and transfer genes of incp plasmids but divergence of the replication functions which are major host-range determinants. | the trfa operon of broad-host-range incp plasmids is essential to activate the origin of vegetative replication in diverse species. the trb operon encodes most of the apparatus for mating pair formation, the first step in conjugative transfer. comparison of the nucleotide sequence of the incp beta plasmid r751 presented here with the equivalent incp alpha sequence identifies conserved features of the organization and regulation of the trfa operon and the region controlling expression of the trb ... | 1996 | 8954881 |
| the primase of broad-host-range plasmid r1162 is active in conjugal transfer. | the broad-host-range plasmid r1162 is conjugally mobilized at high frequency by the incp-1 plasmid r751 but is poorly mobilized by pox38, a derivative of the f factor. in both cases, the origin of transfer (orit) and the mob proteins of r1162 are required, indicating that these plasmids are mobilized by similar mechanisms. r1162 encodes a primase, essential for vegetative replication of the plasmid, that is made both as a separate protein and as the carboxy-terminal domain of moba, one of the r1 ... | 1996 | 8955311 |
| the kile locus of promiscuous incp alpha plasmid rk2 is required for stable maintenance in pseudomonas aeruginosa. | eight coordinately regulated operons constitute the kor regulon of the incp alpha plasmid rk2. three operons specify functions required for replication initiation, conjugative transfer, and control of gene expression. the functions of the other operons, including those of the four coregulated operons that compose the kila, kilc, and kile loci, have not been determined. here, we present the first evidence that a kil determinant is involved in incp plasmid maintenance. elevation of korc levels spe ... | 1997 | 9079921 |
| divergence and conservation of the partitioning and global regulation functions in the central control region of the incp plasmids rk2 and r751. | the central control region (ctl) of incp plasmids is associated with two phenotypes: the coordinate expression of replication and transfer genes; and the ability to increase the segregational stability of a low-copy number test plasmid. this region of the incp beta plasmid r751 shows significant sequence divergence from the incp alpha plasmid rk2 sequence, and two genes, korf and korg, present in the incp alpha region are missing in the incp beta ctl. in other respects the organization of the ct ... | 1997 | 9245806 |
| complete sequence of the incpbeta plasmid r751: implications for evolution and organisation of the incp backbone. | the broad host range incp plasmids are of particular interest because of their ability to promote gene spread between diverse bacterial species. to facilitate study of these plasmids we have compiled the complete sequence of the incpbeta plasmid r751. comparison with the sequence of the incpalpha plasmids confirms the conservation of the incp backbone of replication, conjugative transfer and stable inheritance functions between the two branches of this family. as in the incpalpha genome the dna ... | 1998 | 9753548 |
| the potential of integrons and connected programmed rearrangements for mediating horizontal gene transfer. | site-specific recombination of integrons, mediates transfer of single genes in small genomes and plasmids. recent data suggest that new genes are recruited to the cassettes--the units moved by integrons. integrons are resident in a class of transposons with pronounced target selectivity for resolution loci in broad host range plasmids. a resulting network of programmed transfer routes, with potential offshoots reaching into eukaryotic cells, may channel genes to unexpectedly remote organisms. it ... | 1998 | 9850680 |
| map of the incp1beta plasmid ptsa encoding the widespread genes (tsa) for p-toluenesulfonate degradation in comamonas testosteroni t-2. | the catabolic incp1beta plasmid ptsa from comamonas testosteroni t-2 was mapped by subtractive analysis of restriction digests, by sequencing outwards from the tsa operon (toluenesulfonate degradation), and by generating overlapping, long-distance-pcr amplification products. the plasmid was estimated to comprise 72 +/- 4 kb. the tsa region was found to be a composite transposon flanked by two is1071 elements. a cryptic tsa operon was also present in the tsa transposon. those backbone genes and r ... | 2001 | 11282598 |
| isolation and characterization of clv25, a bacteroides fragilis chromosomal transfer factor resembling multiple bacteroides sp. mobilizable transposons. | horizontal dna transfer contributes significantly to the dissemination of antibiotic resistance genes in bacteroides fragilis. to further our understanding of dna transfer in b. fragilis, we isolated and characterized a new transfer factor, clv25. clv25 was isolated from b. fragilis lv25 by its capture on the nonmobilizable escherichia coli-bacteroides shuttle vector pgat400deltabglii. similar to other bacteroides sp. transfer factors, clv25 was mobilized in e. coli by the conjugative plasmid r7 ... | 2002 | 11889096 |
| bacterial conjugative transfer: visualization of successful mating pairs and plasmid establishment in live escherichia coli. | we used the laco/gfp-laci system to label and visualize the incp beta plasmid r751 fluorescently during conjugative transfer between live donor and recipient bacteria. comparisons of r751 in conjugative and non-conjugative conditions have allowed us to identify key localizations and movements associated with the initiation of conjugative transfer in the donor and the establishment of r751 in the recipient. a survey of successful mating pairs demonstrates that close physical contact between donor ... | 2002 | 12010490 |
| structure of haloacetate-catabolic incp-1beta plasmid puo1 and genetic mobility of its residing haloacetate-catabolic transposon. | the self-transmissible plasmid puo1 from delftia acidovorans strain b carries two haloacetate-catabolic transposons, tnhad1 and tnhad2, and the mer genes for resistance to mercury. the complete 67,066-bp sequence of puo1 revealed that the mer genes were also carried by two tn402/tn5053-like transposons, tn4671 and tn4672, and that the puo1 backbone regions shared 99% identity to those of the archetype incp-1beta plasmid r751. comparison of puo1 with three other incp-1beta plasmids illustrated th ... | 2003 | 14594853 |
| the 64 508 bp incp-1beta antibiotic multiresistance plasmid pb10 isolated from a waste-water treatment plant provides evidence for recombination between members of different branches of the incp-1beta group. | the complete 64508 bp nucleotide sequence of the incp-1beta antibiotic-resistance plasmid pb10, which was isolated from a waste-water treatment plant in germany and mediates resistance against the antimicrobial agents amoxicillin, streptomycin, sulfonamides and tetracycline and against mercury ions, was determined and analysed. a typical class 1 integron with completely conserved 5' and 3' segments is inserted between the tra and trb regions. the two mobile gene cassettes of this integron encode ... | 2003 | 14600226 |
| mechanisms of strand replacement synthesis for plasmid dna transferred by conjugation. | a single strand of plasmid dna is transferred during conjugation. we examined the mechanism of complementary strand synthesis in recipient cells following conjugative mobilization of derivatives of the incq plasmid r1162. a system for electroporation of donor cells, followed by immediate mating, was used to eliminate plasmid-specific replicative functions. under these conditions, escherichia coli recipients provided a robust mechanism for initiation of complementary strand synthesis on transferr ... | 2005 | 15866925 |
| plasmid pb8 is closely related to the prototype incp-1beta plasmid r751 but transfers poorly to escherichia coli and carries a new transposon encoding a small multidrug resistance efflux protein. | the incp-1beta plasmid pb8, which confers resistance to amoxicillin, spectinomycin, streptomycin, and sulfonamides, was previously isolated from a sewage treatment plant. it was found to possess abnormal conjugative transfer properties, i.e., transfer to escherichia coli by conjugation or electroporation could not be detected. we showed in this study that plasmid pb8 is transferable to e. coli by conjugation, but only at low frequencies and under specific experimental conditions, a phenomenon th ... | 2005 | 16122561 |
| the kfra gene is the first in a tricistronic operon required for survival of incp-1 plasmid r751. | the kfra gene of the incp-1 broad-host-range plasmids is the best-studied member of a growing gene family that shows strong linkage to the minimal replicon of many low-copy-number plasmids. kfra is a dna binding protein with a long, alpha-helical, coiled-coil tail. studying incp-1beta plasmid r751, evidence is presented that kfra and its downstream genes upf54.8 and upf54.4 were organized in a tricistronic operon (renamed here kfra kfrb kfrc), expressed from autoregulated kfrap, that was also re ... | 2006 | 16735726 |
| the multiple antibiotic resistance incp-1 plasmid pkjk5 isolated from a soil environment is phylogenetically divergent from members of the previously established alpha, beta and delta sub-groups. | the 54,383bp plasmid pkjk5 was recovered from a soil environment by exogenous plasmid isolation and conveys resistance towards tetracycline and trimethoprim. sequencing and annotation revealed a high level of structural similarity of the backbone genes to other incp-1 plasmids containing a tra1 and tra2 region, a central control module and a replication initiation module. a considerable degree of divergence was associated with the backbone genes of pkjk5 as compared to homologous genes in the al ... | 2007 | 17306874 |