Artículos de revistas: "F plasmid"

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Lin, Mei-Hui, and Shih-Tung Liu. "Stabilization of pSW100 from Pantoea stewartii by the F Conjugation System." Journal of Bacteriology 190, no. 10 (2008): 3681–89. http://dx.doi.org/10.1128/jb.00846-07.

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ABSTRACT Plasmid pSW100 is 1 of the 13 plasmids from Pantoea stewartii subsp. stewartii SW2 which has a replicon that resembles that of ColE1. This work uses a pSW100 derivative, pSW140K, to study how the pSW100 replicon is stably maintained in its hosts. Our results indicate that although pSW140K is stable in Escherichia coli HB101, the plasmid is rapidly lost in another E. coli strain, DH5α, indicating that the genetic background of an E. coli strain affects the stability of pSW140K. Mutagenesis of E. coli HB101 with EZ::TN <DHFR-1> revealed that mutations in traC, traF, traG, traN, and traV, which encode the components of the sex pilus assembly, reduce plasmid stability. Furthermore, this work identified that a 38-bp region located immediately upstream of the RNAII promoter is critical to the maintenance of plasmid stability in E. coli HB101. TraC binds to the region, and in addition, deleting the region destabilizes the plasmid. Furthermore, inserting this 38-bp fragment into a plasmid that contains the minimal replicon from pSW200 stabilizes the plasmid in E. coli HB101. Fluorescence in situ hybridization and immunofluorescence staining also revealed that derivatives of pSW100, pSW128A, and TraC are colocalized in cells, suggesting that pSW100 may use the sex pilus assembly as a partition apparatus to ensure the even distribution of the plasmid during cell division, which may thus maintain the plasmid's stability.

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Matlock, William, Kevin K. Chau, Manal AbuOun, et al. "Genomic network analysis of environmental and livestock F-type plasmid populations." ISME Journal 15, no. 8 (2021): 2322–35. http://dx.doi.org/10.1038/s41396-021-00926-w.

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AbstractF-type plasmids are diverse and of great clinical significance, often carrying genes conferring antimicrobial resistance (AMR) such as extended-spectrum β-lactamases, particularly in Enterobacterales. Organising this plasmid diversity is challenging, and current knowledge is largely based on plasmids from clinical settings. Here, we present a network community analysis of a large survey of F-type plasmids from environmental (influent, effluent and upstream/downstream waterways surrounding wastewater treatment works) and livestock settings. We use a tractable and scalable methodology to examine the relationship between plasmid metadata and network communities. This reveals how niche (sampling compartment and host genera) partition and shape plasmid diversity. We also perform pangenome-style analyses on network communities. We show that such communities define unique combinations of core genes, with limited overlap. Building plasmid phylogenies based on alignments of these core genes, we demonstrate that plasmid accessory function is closely linked to core gene content. Taken together, our results suggest that stable F-type plasmid backbone structures can persist in environmental settings while allowing dramatic variation in accessory gene content that may be linked to niche adaptation. The association of F-type plasmids with AMR may reflect their suitability for rapid niche adaptation.

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Boyd, E. Fidelma, Charles W. Hill, Stephen M. Rich, and Daniel L. Hartl. "Mosaic Structure of Plasmids From Natural Populations of Escherichia coli." Genetics 143, no. 3 (1996): 1091–100. http://dx.doi.org/10.1093/genetics/143.3.1091.

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Abstract The distribution of plasmids related to the fertility factor F was examined in the ECOR reference collection of Escherichia coli. Probes specific for four F-related genes were isolated and used to survey the collection by DNA hybridization. To estimate the genetic diversity of genes in F-like plasmids, DNA sequences were obtained for four plasmid genes. The phylogenetic relationships among the plasmids in the ECOR strains is very different from that of the strains themselves. This finding supports the view that plasmid transfer has been frequent within and between the major groups of ECOR. Furthermore, the sequences indicate that recombination between genes in plasmids takes place at a considerably higher frequency than that observed for chromosomal genes. The plasmid genes, and by inference the plasmids themselves, are mosaic in structure with different regions acquired from different sources. Comparison of gene sequences from a variety of naturally occurring plasmids suggested a plausible donor of some of the recombinant regions as well as implicating a chi site in the mechanism of genetic exchange. The relatively high rate of recombination in F-plasmid genes suggests that conjugational gene transfer may play a greater role in bacterial population structure than previously appreciated.

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Haake, Susan Kinder, Sean C. Yoder, Gwynne Attarian, and Kara Podkaminer. "Native Plasmids of Fusobacterium nucleatum: Characterization and Use in Development of Genetic Systems." Journal of Bacteriology 182, no. 4 (2000): 1176–80. http://dx.doi.org/10.1128/jb.182.4.1176-1180.2000.

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ABSTRACT Three native plasmids of Fusobacterium nucleatum were characterized, including DNA sequence analysis of one plasmid, pFN1. A shuttle plasmid, pHS17, capable of transforming Escherichia coli and F. nucleatum ATCC 10953 was constructed with pFN1. pHS17 was stably maintained in the F. nucleatum transformants, and differences in the transformation efficiencies suggested the presence of a restriction-modification system in F. nucleatum.

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May, Thithiwat, and Satoshi Okabe. "Escherichia coli Harboring a Natural IncF Conjugative F Plasmid Develops Complex Mature Biofilms by Stimulating Synthesis of Colanic Acid and Curli." Journal of Bacteriology 190, no. 22 (2008): 7479–90. http://dx.doi.org/10.1128/jb.00823-08.

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ABSTRACT It has been shown that Escherichia coli harboring the derepressed IncFI and IncFII conjugative F plasmids form complex mature biofilms by using their F-pilus connections, whereas a plasmid-free strain forms only patchy biofilms. Therefore, in this study we investigated the contribution of a natural IncF conjugative F plasmid to the formation of E. coli biofilms. Unlike the presence of a derepressed F plasmid, the presence of a natural IncF F plasmid promoted biofilm formation by generating the cell-to-cell mating F pili between pairs of F+ cells (approximately two to four pili per cell) and by stimulating the formation of colanic acid and curli meshwork. Formation of colanic acid and curli was required after the initial deposition of F-pilus connections to generate a three-dimensional mushroom-type biofilm. In addition, we demonstrated that the conjugative factor of F plasmid, rather than a pilus synthesis function, was involved in curli production during biofilm formation, which promoted cell-surface interactions. Curli played an important role in the maturation process. Microarray experiments were performed to identify the genes involved in curli biosynthesis and regulation. The results suggested that a natural F plasmid was more likely an external activator that indirectly promoted curli production via bacterial regulatory systems (the EnvZ/OmpR two-component regulators and the RpoS and HN-S global regulators). These data provided new insights into the role of a natural F plasmid during the development of E. coli biofilms.

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Haryanto, Aris, Hevi Wihadmadyatami, and Nastiti Wijayanti. "In vitro expression of the recombinant fusion protein of Newcastle disease virus from local Indonesian isolates by using a cell-free protein expression system." Indonesian Journal of Biotechnology 25, no. 2 (2020): 69. http://dx.doi.org/10.22146/ijbiotech.54703.

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The aim of this work was the in vitro expression of the recombinant fusion (F) protein of Newcastle disease virus (NDV). The pBT7-N-His-Fusion-NDV expression plasmid which carries the recombinant F protein encoding gene from local Indonesian isolates, was prepared and transformed into E. coli BL21 (DE3). To detect bacterial colonies carrying the recombinant plasmid, a restriction endonuclease analysis was performed using the EcoRI restriction endonuclease. These results showed that the pBT-N-His-Fusion-NDV plasmid was successfully isolated with a size of 4.601 bp, and three recombinant plasmids carrying the gene coding for the recombinant F protein of NDV were obtained. Selected recombinant plasmids were then in vitro by using a cell-free protein expression system followed by visualization of the recombinant F protein on a 12% SDS-PAGE gel both by Coomassie Brilliant Blue staining and Western blotting. Recombinant F protein was successfully in vitro expressed by using a cell-free protein expression system as indicated by a specific single protein band with a molecular mass of 25.6 kDa.

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Boyd, E. Fidelma, and Daniel L. Hartl. "Salmonella Virulence Plasmid: Modular Acquisition of the spv Virulence Region by an F-Plasmid in Salmonella enterica Subspecies I and Insertion Into the Chromosome of Subspecies II, IIIa, IV and VII Isolates." Genetics 149, no. 3 (1998): 1183–90. http://dx.doi.org/10.1093/genetics/149.3.1183.

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Abstract The spv operon is common to all Salmonella virulence plasmids. DNA hybridization analysis indicates that the spv region is limited in distribution to serovars of Salmonella enterica subspecies I, II, IIIa, IV, and VII and is absent from Salmonella bongori isolates. Among strains of subspecies II, IIIa, and VII, all isolates examined contained sequences that hybridized with the spv region. However, among isolates of subspecies I, DNA sequences capable of hybridizing with the spv region were found in some isolates of certain serovars. Furthermore, in isolates of subspecies I, the virulence plasmid was found in the same set of isolates as an F-related plasmid, as determined by the presence of the spv region of the virulence plasmid and the finO, traD, and repA sequences of the F-plasmid. The concordance of the virulence plasmid and all three F-plasmid sequences in subspecies I serovar Choleraesuis, Paratyphi, and Typhimurium is most easily explained if the spv region is carried in an F-related plasmid in these isolates. In contrast, among S. enterica subspecies II, IIIa, IV, and VII, the isolates that contain spv sequences did not hybridize with an F-related plasmid or any other identifiable plasmid. With the use of pulse-field gel electrophoresis, the spv region in subspecies II, IIIa, and VII was found to be encoded on the chromosome. Analysis of the phylogenetic distribution of spv among Salmonella isolates and comparative nucleotide sequence analysis of spvA and spvC suggests that the spv region was acquired very recently, after speciation of the salmonellae.

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Dostál, Lubomír, Sichen Shao, and Joel F. Schildbach. "Tracking F plasmid TraI relaxase processing reactions provides insight into F plasmid transfer." Nucleic Acids Research 39, no. 7 (2010): 2658–70. http://dx.doi.org/10.1093/nar/gkq1137.

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9

Hammerl, Jens A., Iris Klein, Erich Lanka, Bernd Appel, and Stefan Hertwig. "Genetic and Functional Properties of the Self-Transmissible Yersinia enterocolitica Plasmid pYE854, Which Mobilizes the Virulence Plasmid pYV." Journal of Bacteriology 190, no. 3 (2007): 991–1010. http://dx.doi.org/10.1128/jb.01467-07.

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ABSTRACT Yersinia strains frequently harbor plasmids, of which the virulence plasmid pYV, indigenous in pathogenic strains, has been thoroughly characterized during the last decades. Yet, it has been unknown whether the nonconjugative pYV can be transferred by helper plasmids naturally occurring in this genus. We have isolated the conjugative plasmids pYE854 (95.5 kb) and pYE966 (70 kb) from a nonpathogenic and a pathogenic Yersinia enterocolitica strain, respectively, and demonstrate that both plasmids are able to mobilize pYV. The complete sequence of pYE854 has been determined. The transfer proteins and oriT of the plasmid reveal similarities to the F factor. However, the pYE854 replicon does not belong to the IncF group and is more closely related to a plasmid of gram-positive bacteria. Plasmid pYE966 is very similar to pYE854 but lacks two DNA regions of the larger plasmid that are dispensable for conjugation.

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Dionisio, Francisco, Ivan Matic, Miroslav Radman, Olivia R. Rodrigues, and François Taddei. "Plasmids Spread Very Fast in Heterogeneous Bacterial Communities." Genetics 162, no. 4 (2002): 1525–32. http://dx.doi.org/10.1093/genetics/162.4.1525.

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Abstract Conjugative plasmids can mediate gene transfer between bacterial taxa in diverse environments. The ability to donate the F-type conjugative plasmid R1 greatly varies among enteric bacteria due to the interaction of the system that represses sex-pili formations (products of finOP) of plasmids already harbored by a bacterial strain with those of the R1 plasmid. The presence of efficient donors in heterogeneous bacterial populations can accelerate plasmid transfer and can spread by several orders of magnitude. Such donors allow millions of other bacteria to acquire the plasmid in a matter of days whereas, in the absence of such strains, plasmid dissemination would take years. This “amplification effect” could have an impact on the evolution of bacterial pathogens that exist in heterogeneous bacterial communities because conjugative plasmids can carry virulence or antibiotic-resistance genes.

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11

Kline, Bruce C. "Aspects of plasmid F maintenance in Escherichia coli." Canadian Journal of Microbiology 34, no. 4 (1988): 526–35. http://dx.doi.org/10.1139/m88-090.

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A major class of replicons in procaryotes is typified by low copy number, nonrandom intracellular distribution, and stable inheritance. Included in this class are chromosomes of gram-positive and gram-negative bacteria as well as a number of plasmids from these organisms. Replicons in this major class have remarkable structural and functional similarities in the genes that effect and control replication. In the present work a review of plasmid F is presented as a paradigm for many aspects of this group's maintenance features.

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12

Matson, Steven W., Juliana K. Sampson, and Devon R. N. Byrd. "F Plasmid Conjugative DNA Transfer." Journal of Biological Chemistry 276, no. 4 (2000): 2372–79. http://dx.doi.org/10.1074/jbc.m008728200.

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13

van Zyl, Leonard J., Shelly M. Deane, Lilly-Ann Louw, and Douglas E. Rawlings. "Presence of a Family of Plasmids (29 to 65 Kilobases) with a 26-Kilobase Common Region in Different Strains of the Sulfur-Oxidizing Bacterium Acidithiobacillus caldus." Applied and Environmental Microbiology 74, no. 14 (2008): 4300–4308. http://dx.doi.org/10.1128/aem.00864-08.

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ABSTRACT Three large cryptic plasmids from different isolates of Acidithiobacillus caldus were rescued by using an in vitro transposition system that delivers a kanamycin-selectable marker and an Escherichia coli plasmid origin of replication. The largest of the plasmids, the 65-kb plasmid pTcM1, was isolated from a South African A. caldus strain, MNG. This plasmid was sequenced and compared to that of pTcF1 (39 kb, from strain “f,” South Africa) and pC-SH12 (29 kb, from strain C-SH12, Australia). With the exception of a 2.7-kb insertion sequence, pC-SH12 appears to represent the DNA common to all three plasmids and includes a number of accessory genes plus the plasmid “backbone” containing the replication region. The two larger plasmids carry, in addition, a number of insertion sequences of the ISL3 family and a composite transposon related to the Tn21 subfamily containing a highly mosaic region within the borders of the inverted repeats. Genes coding for arsenic resistance, plasmid mobilization, plasmid stability, and a putative restriction-modification system occur within these mosaic regions.

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Chu, Chishih, Cheng-Hsun Chiu, Chi-Hong Chu, and Jonathan T. Ou. "Nucleotide and Amino Acid Sequences of oriT-traM-traJ-traY-traA-traL Regions and Mobilization of Virulence Plasmids of Salmonella enterica Serovars Enteritidis, Gallinarum-Pullorum, and Typhimurium." Journal of Bacteriology 184, no. 11 (2002): 2857–62. http://dx.doi.org/10.1128/jb.184.11.2857-2862.2002.

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ABSTRACT The virulence plasmid of Salmonella enterica serovar Gallinarum-Pullorum (pSPV) but not those of Salmonella enterica serovars Enteritidis (pSEV) and Typhimurium (pSTV) can be readily mobilized by an F or F-like conjugative plasmid. To investigate the reason for the difference, the oriT-traM-traJ-traY-traA-traL regions of the three salmonella virulence plasmids (pSVs) were cloned and their nucleotide and deduced amino acid sequences were examined. The cloned fragments were generally mobilized more readily than the corresponding full-length pSVs, but the recombinant plasmid containing the oriT of pSPV was, as expected, more readily mobilized, with up to 100-fold higher frequency than the recombinant plasmids containing the oriT of the other two pSVs. The nucleotide sequences of the oriT-traM-traJ-traY-traA-traL region of pSEV and pSTV were almost identical (only 4 bp differences), but differed from that of pSPV. Major nucleotide sequence variations were found in traJ, traY, and the Tra protein binding sites sby and sbm. sby of pSPV showed higher similarity than that of pSEV or pSTV to that of the F plasmid. The reverse was true for sbm: similarity was higher with pSEV and pSTV than with pSPV. In the deduced amino acid sequences of the five Tra proteins, major differences were found in TraY: pSEV's TraY was 75 amino acids, pSTV's was 106 amino acids, and pSPV's was 133 amino acids; and there were duplicate consensus βαα fragments in the TraY of pSPV and F plasmid, whereas there was only a single βαα fragment in that of pSEV and pSTV.

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Paula, Marcia O., Elerson GaettiI-Jardim Jr., and Mario J. Avilla-Campos. "Plasmid profile in oral Fusobacterium nucleatum from humans and Cebus apella monkeys." Revista do Instituto de Medicina Tropical de São Paulo 45, no. 1 (2003): 05–09. http://dx.doi.org/10.1590/s0036-46652003000100002.

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Fusobacterium nucleatum is a strict anaerobe and is indigenous of the human oral cavity. This organism is commonly recovered from different monomicrobial and mixed infections in humans and animals. In this study, the plasmid profile, the plasmid stability and the penicillin-resistance association in oral F. nucleatum isolated from periodontal patients, healthy subjects and Cebus apella monkeys were evaluated. Forty-five F. nucleatum strains from patients, 38 from healthy subjects and seven from C. apella were identified and analyzed. Plasmid extraction was performed in all the isolated strains. These elements were found in 26.7% strains from patients and one strain from C. apella. Strains from healthy subjects did not show any plasmid. Most of strains showed two plasmid bands ranging from 4 to 16 Kb, but digestions with endonucleases showed that they belonged to a single plasmid. The plasmid profile was similar and stable in human and monkey strains. Also, plasmids were classified into three groups according to size. Two strains were positive to beta-lactamase production and no plasmid DNA-hybridization with a beta-lactamase gene probe was observed, suggesting a chromosomal resistance.

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Gardner, Murray N., Shelly M. Deane, and Douglas E. Rawlings. "Isolation of a New Broad-Host-Range IncQ-Like Plasmid, pTC-F14, from the Acidophilic Bacterium Acidithiobacillus caldus and Analysis of the Plasmid Replicon." Journal of Bacteriology 183, no. 11 (2001): 3303–9. http://dx.doi.org/10.1128/jb.183.11.3303-3309.2001.

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ABSTRACT A moderately thermophilic (45 to 50°C), highly acidophilic (pH 1.5 to 2.5), chemolithotrophic Acidithiobacillus caldusstrain, f, was isolated from a biooxidation process used to treat nickel ore. Trans-alternating field electrophoresis analysis of total DNA from the A. caldus cells revealed two plasmids of approximately 14 and 45 kb. The 14-kb plasmid, designated pTC-F14, was cloned and shown by replacement of the cloning vector with a kanamycin resistance gene to be capable of autonomous replication inEscherichia coli. Autonomous replication was also demonstrated in Pseudomonas putida andAgrobacterium tumefaciens LBA 4404, which suggested that pTC-F14 is a broad-host-range plasmid. Sequence analysis of the pTC-F14 replicon region revealed five open reading frames and a replicon organization like that of the broad-host-range IncQ plasmids. Three of the open reading frames encoded replication proteins which were most closely related to those of IncQ-like plasmid pTF-FC2 (amino acid sequence identities: RepA, 81%; RepB, 78%; RepC, 74%). However, the two plasmids were fully compatible and pTC-F14 represents a new IncQ-like plasmid replicon. Surprisingly, asymmetrical incompatibility was found with the less closely related IncQ plasmid R300B derivative pKE462 and the IncQ-like plasmid derivative pIE1108. Analysis of the pTC-F14 oriV region revealed five direct repeats consisting of three perfectly conserved 22-bp iterons flanked by iterons of 23 and 21 bp. Plasmid pTC-F14 had a copy number of 12 to 16 copies per chromosome in both E. coli, and A. caldus. The rep gene products of pTC-F14 and pTF-FC2 were unable to functionally complement each other'soriV regions, but replication occurred when the genes for each plasmid's own RepA, RepB, and RepC proteins were provided intrans. Two smaller open reading frames were found between the repB and repA genes of pTC-F14, which encode proteins with high amino acid sequence identity (PasA, 81%; PasB, 72%) to the plasmid addiction system of pTF-FC2. This is the second time a plasmid stability system of this type has been found on an IncQ-like plasmid.

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Fekete, Richard A., and Laura S. Frost. "Mobilization of Chimeric oriT Plasmids by F and R100-1: Role of Relaxosome Formation in Defining Plasmid Specificity." Journal of Bacteriology 182, no. 14 (2000): 4022–27. http://dx.doi.org/10.1128/jb.182.14.4022-4027.2000.

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ABSTRACT Cleavage at the F plasmid nic site within the origin of transfer (oriT) requires the F-encoded proteins TraY and TraI and the host-encoded protein integration host factor in vitro. We confirm that F TraY, but not F TraM, is required for cleavage atnic in vivo. Chimeric plasmids were constructed which contained either the entire F or R100-1 oriT regions or various combinations of nic, TraY, and TraM binding sites, in addition to the traM gene. The efficiency of cleavage atnic and the frequency of mobilization were assayed in the presence of F or R100-1 plasmids. The ability of these chimeric plasmids to complement an F traM mutant or affect F transfer via negative dominance was also measured using transfer efficiency assays. In cases where cleavage at nic was detected, R100-1 TraI was not sensitive to the two-base difference in sequence immediately downstream of nic, while F TraI was specific for the F sequence. Plasmid transfer was detected only when TraM was able to bind to its cognate sites within oriT. High-affinity binding of TraY in cis to oriTallowed detection of cleavage at nic but was not required for efficient mobilization. Taken together, our results suggest that stable relaxosomes, consisting of TraI, -M, and -Y bound to oriT are preferentially targeted to the transfer apparatus (transferosome).

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Ravin, N., and D. Lane. "Partition of the Linear Plasmid N15: Interactions of N15 Partition Functions with the sop Locus of the F Plasmid." Journal of Bacteriology 181, no. 22 (1999): 6898–906. http://dx.doi.org/10.1128/jb.181.22.6898-6906.1999.

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ABSTRACT A locus close to one end of the linear N15 prophage closely resembles the sop operon which governs partition of the F plasmid; the promoter region contains similar operator sites, and the two putative gene products have extensive amino acid identity with the SopA and -B proteins of F. Our aim was to ascertain whether the N15sop homologue functions in partition, to identify the centromere site, and to examine possible interchangeability of function with the F Sop system. When expressed at a moderate level, N15 SopA and -B proteins partly stabilize mini-F which lacks its own sopoperon but retains the sopC centromere. The stabilization does not depend on increased copy number. Likewise, an N15 mutant with most of its sop operon deleted is partly stabilized by F Sop proteins and fully stabilized by its own. Four inverted repeat sequences similar to those of sopC were located in N15. They are distant from the sop operon and from each other. Two of these were shown to stabilize a mini-F sop deletion mutant when N15 Sop proteins were provided. Provision of the SopA homologue to plasmids with a sopA deletion resulted in further destabilization of the plasmid. The N15 Sop proteins exert effective, but incomplete, repression at the F soppromoter. We conclude that the N15 sop locus determines stable inheritance of the prophage by using dispersed centromere sites. The SopB-centromere and SopA-operator interactions show partial functional overlap between N15 and F. SopA of each plasmid appears to interact with SopB of the other, but in a way that is detrimental to plasmid maintenance.

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Hu, Bo, Pratick Khara, and Peter J. Christie. "Structural bases for F plasmid conjugation and F pilus biogenesis inEscherichia coli." Proceedings of the National Academy of Sciences 116, no. 28 (2019): 14222–27. http://dx.doi.org/10.1073/pnas.1904428116.

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Bacterial conjugation systems are members of the large type IV secretion system (T4SS) superfamily. Conjugative transfer of F plasmids residing in theEnterobacteriaceaewas first reported in the 1940s, yet the architecture of F plasmid-encoded transfer channel and its physical relationship with the F pilus remain unknown. We visualized F-encoded structures in the native bacterial cell envelope by in situ cryoelectron tomography (CryoET). Remarkably, F plasmids encode four distinct structures, not just the translocation channel or channel-pilus complex predicted by prevailing models. The F1 structure is composed of distinct outer and inner membrane complexes and a connecting cylinder that together house the envelope-spanning translocation channel. The F2 structure is essentially the F1 complex with the F pilus attached at the outer membrane (OM). Remarkably, the F3 structure consists of the F pilus attached to a thin, cell envelope-spanning stalk, whereas the F4 structure consists of the pilus docked to the OM without an associated periplasmic density. The traffic ATPase TraC is configured as a hexamer of dimers at the cytoplasmic faces of the F1 and F2 structures, where it respectively regulates substrate transfer and F pilus biogenesis. Together, our findings present architectural renderings of the DNA conjugation or “mating” channel, the channel–pilus connection, and unprecedented pilus basal structures. These structural snapshots support a model for biogenesis of the F transfer system and allow for detailed comparisons with other structurally characterized T4SSs.

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García-Quintanilla, Meritxell, Ana I. Prieto, Laurent Barnes, Francisco Ramos-Morales, and Josep Casadesús. "Bile-Induced Curing of the Virulence Plasmid in Salmonella enterica Serovar Typhimurium." Journal of Bacteriology 188, no. 22 (2006): 7963–65. http://dx.doi.org/10.1128/jb.00995-06.

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ABSTRACT Exposure to bile induces curing of the virulence plasmid in Salmonella enterica serovar Typhimurium (pSLT). Disruption of the ccdB gene increases pSLT curing, both spontaneous and induced by bile, suggesting that the pSLT ccdAB genes may encode a homolog of the CcdAB addiction module previously described in the F sex factor. Unlike the F sex factor, synthesis of pSLT-encoded pili does not confer bile sensitivity. These observations may provide insights into the evolution of virulence plasmids in Salmonella subspecies I, as well as the causes of virulence plasmid loss in other Salmonella subspecies.

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Roig, Francisco J., and Carmen Amaro. "Plasmid diversity in Vibrio vulnificus biotypes." Microbiology 155, no. 2 (2009): 489–97. http://dx.doi.org/10.1099/mic.0.023424-0.

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Vibrio vulnificus is a heterogeneous bacterial species that can be virulent for humans and fish. Virulence in fish seems to rely on a recently described plasmid that can be transmitted between strains, aided by a conjugative plasmid. The main objective of this work was to analyse the plasmid content of a wide collection of strains from the three biotypes of the species, as well as to identify putative conjugative and virulence plasmids by means of Southern hybridization with specific probes and sequence analysis of selected gene markers. We found 28 different plasmid profiles in a total of 112 strains, which were relatively biotype- or serovar-specific. Biotype 1 lacked high-molecular-mass plasmids, with the exception of a putative conjugative plasmid of 48 kb that was present in 42.8 % of clinical and environmental strains isolated worldwide. All biotype 2 strains possessed the virulence plasmid, whose molecular mass ranged between 68 and 70 kb, and 89.65 % of these strains also had a putative conjugative plasmid with a molecular size of 52–56 kb. Finally, a 48 kb putative conjugative plasmid was present in all biotype 3 strains. Data from partial sequencing of traD, traI and the whole vep07 (a recently described plasmid-borne virulence gene) from a selection of strains suggest that the plasmids of 48–56 kb probably belong to the same family of F-plasmids as pYJ016 and that the gene vep07 is absolutely essential for fish virulence. Additional cryptic plasmids of low molecular mass were present in the three biotypes. In conclusion, plasmids are widespread among V. vulnificus species and could contribute substantially to genetic plasticity of the species.

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Lane, David, René Rothenbuehler, Anne-Marie Merrillat, and Carolyn Aiken. "Analysis of the F plasmid centromere." Molecular and General Genetics MGG 207, no. 2-3 (1987): 406–12. http://dx.doi.org/10.1007/bf00331608.

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Maier, Tamara M., Andrea Havig, Monika Casey, Francis E. Nano, Dara W. Frank, and Thomas C. Zahrt. "Construction and Characterization of a Highly Efficient Francisella Shuttle Plasmid." Applied and Environmental Microbiology 70, no. 12 (2004): 7511–19. http://dx.doi.org/10.1128/aem.70.12.7511-7519.2004.

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ABSTRACT Francisella tularensis is a facultative intracellular pathogen that infects a wide variety of mammals and causes tularemia in humans. It is recognized as a potential agent of bioterrorism due to its low infectious dose and multiple routes of transmission. To date, genetic manipulation in Francisella spp. has been limited due to the inefficiency of DNA transformation, the relative lack of useful selective markers, and the lack of stably replicating plasmids. Therefore, the goal of this study was to develop an enhanced shuttle plasmid that could be utilized for a variety of genetic procedures in both Francisella and Escherichia coli. A hybrid plasmid, pFNLTP1, was isolated that was transformed by electroporation at frequencies of >1 × 107 CFU μg of DNA−1 in F. tularensis LVS, Francisella novicida U112, and E. coli DH5α. Furthermore, this plasmid was stably maintained in F. tularensis LVS after passage in the absence of antibiotic selection in vitro and after 3 days of growth in J774A.1 macrophages. Importantly, F. tularensis LVS derivatives carrying pFNLTP1 were unaltered in their growth characteristics in laboratory medium and macrophages compared to wild-type LVS. We also constructed derivatives of pFNLTP1 containing expanded multiple cloning sites or temperature-sensitive mutations that failed to allow plasmid replication in F. tularensis LVS at the nonpermissive temperature. In addition, the utility of pFNLTP1 as a vehicle for gene expression, as well as complementation, was demonstrated. In summary, we describe construction of a Francisella shuttle plasmid that is transformed at high efficiency, is stably maintained, and does not alter the growth of Francisella in macrophages. This new tool should significantly enhance genetic manipulation and characterization of F. tularensis and other Francisella biotypes.

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Golubov, Andrey, Heinrich Neubauer, Christina Nölting, Jürgen Heesemann, and Alexander Rakin. "Structural Organization of the pFra Virulence-Associated Plasmid of Rhamnose-Positive Yersinia pestis." Infection and Immunity 72, no. 10 (2004): 5613–21. http://dx.doi.org/10.1128/iai.72.10.5613-5621.2004.

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ABSTRACT The 137,036-bp plasmid pG8786 from rhamnose-positive Yersinia pestis G8786 isolated from the high mountainous Caucasian plague focus in Georgia is an enlarged form of the pFra virulence-associated plasmid containing genes for synthesis of the antigen fraction 1 and phospholipase D. In addition to the completely conserved genes of the pFra backbone, pG8786 contains two large regions consisting of 4,642 and 32,617 bp, designated regions 1 and 2, respectively. Region 1 retains a larger part of Salmonella enterica serovar Typhi plasmid pHCM2 resembling the backbone of pFra replicons, while region 2 contains 25 open reading frames with high levels of similarity to the transfer genes of the F-like plasmids. Surprisingly, region 1 is also present in the pFra plasmid of avirulent Y. pestis strain 91001 isolated in Inner Mongolia, People's Republic of China. Despite the fact that some genes typically involved in conjugative transfer of the F-like replicons are missing in pG8786, we cannot exclude the possibility that pG8786 might be transmissive under certain conditions. pG8786 seems to be an ancient form of the pFra group of plasmids that were conserved due to the strict geographical isolation of rhamnose-positive Y. pestis strains in the high mountainous Caucasian plague locus.

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25

Lorenz, Sandra C., Steven R. Monday, Maria Hoffmann, Markus Fischer, and Julie A. Kase. "Plasmids from Shiga Toxin-Producing Escherichia coli Strains with Rare Enterohemolysin Gene (ehxA) Subtypes Reveal Pathogenicity Potential and Display a Novel Evolutionary Path." Applied and Environmental Microbiology 82, no. 21 (2016): 6367–77. http://dx.doi.org/10.1128/aem.01839-16.

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ABSTRACTMost Shiga toxin-producingEscherichia coli(STEC) strains associated with severe disease, such as hemolytic-uremic syndrome (HUS), carry large enterohemolysin-encoding (ehxA) plasmids, e.g., pO157 and pO103, that contribute to STEC clinical manifestations. SixehxAsubtypes (A through F) exist that phylogenetically cluster intoeae-positive (B, C, F), a mix ofeae-positive (E) andeae-negative (A), and a third, more distantly related, cluster ofeae-negative (D) STEC strains. While subtype B, C, and F plasmids share a number of virulence traits that are distinct from those of subtype A, sequence data have not been available for subtype D and E plasmids. Here, we determined and compared the genetic composition of four subtype D and two subtype E plasmids to establish their evolutionary relatedness amongehxAsubtypes and define their potential role in pathogenicity. We found that subtype D strains carry one exceptionally large plasmid (>200 kbp) that carries a variety of virulence genes that are associated with enterotoxigenic and enterohemorrhagicE. coli, which, quite possibly, enables these strains to cause disease despite being food isolates. Our data offer further support for the hypothesis that this subtype D plasmid represents a novel virulence plasmid, sharing very few genetic features with other plasmids; we conclude that these plasmids have evolved from a different evolutionary lineage than the plasmids carrying the otherehxAsubtypes. In contrast, the 50-kbp plasmids of subtype E (pO145), although isolated from HUS outbreak strains, carried only few virulence-associated determinants, suggesting that the clinical presentation of subtype E strains is largely a result of chromosomally encoded virulence factors.IMPORTANCEBacterial plasmids are known to be key agents of change in microbial populations, promoting the dissemination of various traits, such as drug resistance and virulence. This study determined the genetic makeup of virulence plasmids from rare enterohemolysin subtype D and E Shiga toxin-producingE. colistrains. We demonstrated thatehxAsubtype D plasmids represent a novelE. colivirulence plasmid, and although subtype D plasmids were derived from nonclinical isolates, they encoded a variety of virulence determinants that are associated with pathogenicE. coli. In contrast, subtype E plasmids, isolated from strains recovered from severely ill patients, carry only a few virulence determinants. The results of this study reemphasize the plasticity and vast diversity amongE. coliplasmids. This work demonstrates that, althoughE. colistrains of certain serogroups may not be frequently associated with disease, they should not be underestimated in protecting human health and food safety.

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Haft, Rembrandt J. F., Gilberto Palacios, Tran Nguyen, et al. "General Mutagenesis of F Plasmid TraI Reveals Its Role in Conjugative Regulation." Journal of Bacteriology 188, no. 17 (2006): 6346–53. http://dx.doi.org/10.1128/jb.00462-06.

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ABSTRACT Bacteria commonly exchange genetic information by the horizontal transfer of conjugative plasmids. In gram-negative conjugation, a relaxase enzyme is absolutely required to prepare plasmid DNA for transit into the recipient via a type IV secretion system. Here we report a mutagenesis of the F plasmid relaxase gene traI using in-frame, 31-codon insertions. Phenotypic analysis of our mutant library revealed that several mutant proteins are functional in conjugation, highlighting regions of TraI that can tolerate insertions of a moderate size. We also demonstrate that wild-type TraI, when overexpressed, plays a dominant-negative regulatory role in conjugation, repressing plasmid transfer frequencies ∼100-fold. Mutant TraI proteins with insertions in a region of approximately 400 residues between the consensus relaxase and helicase sequences did not cause conjugative repression. These unrestrictive TraI variants have normal relaxase activity in vivo, and several have wild-type conjugative functions when expressed at normal levels. We postulate that TraI negatively regulates conjugation by interacting with and sequestering some component of the conjugative apparatus. Our data indicate that the domain responsible for conjugative repression resides in the central region of TraI between the protein's catalytic domains.

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Johnson, Timothy J., Kylie E. Siek, Sara J. Johnson, and Lisa K. Nolan. "DNA Sequence and Comparative Genomics of pAPEC-O2-R, an Avian Pathogenic Escherichia coli Transmissible R Plasmid." Antimicrobial Agents and Chemotherapy 49, no. 11 (2005): 4681–88. http://dx.doi.org/10.1128/aac.49.11.4681-4688.2005.

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ABSTRACT In this study, a 101-kb IncF plasmid from an avian pathogenic Escherichia coli (APEC) strain (APEC O2) was sequenced and analyzed, providing the first completed APEC plasmid sequence. This plasmid, pAPEC-O2-R, has functional transfer and antimicrobial resistance-encoding regions. The resistance-encoding region encodes resistance to eight groups of antimicrobial agents, including silver and other heavy metals, quaternary ammonium compounds, tetracycline, sulfonamides, aminoglycosides, trimethoprim, and beta-lactam antimicrobial agents. This region of the plasmid is unique among previously described IncF plasmids in that it possesses a class 1 integron that harbors three gene cassettes and a heavy metal resistance operon. This region spans 33 kb and is flanked by the RepFII plasmid replicon and an assortment of plasmid maintenance genes. pAPEC-O2-R also contains a 32-kb transfer region that is nearly identical to that found in the E. coli F plasmid, rendering it transferable by conjugation to plasmid-less strains of bacteria, including an APEC strain, a fecal E. coli strain from an apparently healthy bird, a Salmonella enterica serovar Typhimurium strain, and a uropathogenic E. coli strain from humans. Differences in the G+C contents of individual open reading frames suggest that various regions of pAPEC-O2-R had dissimilar origins. The presence of pAPEC-O2-R-like plasmids that encode resistance to multiple antimicrobial agents and that are readily transmissible from APEC to other bacteria suggests the possibility that such plasmids may serve as a reservoir of resistance genes for other bacteria of animal and human health significance.

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Bachrach, Gilad, Susan Kinder Haake, Alon Glick, et al. "Characterization of the Novel Fusobacterium nucleatum Plasmid pKH9 and Evidence of an Addiction System." Applied and Environmental Microbiology 70, no. 12 (2004): 6957–62. http://dx.doi.org/10.1128/aem.70.12.6957-6962.2004.

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ABSTRACT Fusobacterium nucleatum is an important oral anaerobic pathogen involved in periodontal and systemic infections. Studies of the molecular mechanisms involved in fusobacterial virulence and adhesion have been limited by lack of systems for efficient genetic manipulation. Plasmids were isolated from eight strains of F. nucleatum. The smallest plasmid, pKH9 (4,975 bp), was characterized and used to create new vectors for fusobacterial genetic manipulation. DNA sequence analysis of pKH9 revealed an open reading frame (ORF) encoding a putative autonomous rolling circle replication protein (Rep), an ORF predicted to encode a protein homologous to members of the FtsK/SpoIIIE cell division-DNA segregation protein family, and an operon encoding a putative toxin-antitoxin plasmid addiction system (txf-axf). Deletion analysis localized the pKH9 replication region in a 0.96-kbp fragment. The pKH9 rep gene is not present in this fragment, suggesting that pKH9 can replicate in fusobacteria independently of the Rep protein. A pKH9-based, compact Escherichia coli-F. nucleatum shuttle plasmid was constructed and found to be compatible with a previously described pFN1-based fusobacterial shuttle plasmid. Deletion of the pKH9 putative addiction system (txf-axf) reduced plasmid stability in fusobacteria, indicating its addiction properties and suggesting it to be the first plasmid addiction system described for fusobacteria. pKH9, its genetic elements, and its shuttle plasmid derivatives can serve as useful tools for investigating fusobacterial properties important in biofilm ecology and pathogenesis.

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29

Onogi, Toshinari, Takeyoshi Miki, and Sota Hiraga. "Behavior of Sister Copies of Mini-F Plasmid after Synchronized Plasmid Replication in Escherichia coli Cells." Journal of Bacteriology 184, no. 11 (2002): 3142–45. http://dx.doi.org/10.1128/jb.184.11.3142-3145.2002.

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ABSTRACT To clarify whether sister copies of mini-F plasmid are immediately separated from each other after replication, we analyzed the behavior of sister mini-F copies after synchronized replication of mini-F. Sister copies of mini-F were separated immediately or shortly after replication, in contrast to sister oriC copies of the Escherichia coli chromosome.

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30

Kato, Jun-ichi, and Hideo Ikeda. "Construction of mini-F plasmid vectors for plasmid shuffling in Escherichia coli." Gene 170, no. 1 (1996): 141–42. http://dx.doi.org/10.1016/0378-1119(95)00865-9.

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31

Sastre, J. Ignacio, Elena Cabezón, and Fernando de la Cruz. "The Carboxyl Terminus of Protein TraD Adds Specificity and Efficiency to F-Plasmid Conjugative Transfer." Journal of Bacteriology 180, no. 22 (1998): 6039–42. http://dx.doi.org/10.1128/jb.180.22.6039-6042.1998.

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ABSTRACT We isolated and characterized traD mutants with an altered specificity of interaction with relaxosomes of various conjugative (F and R388) and mobilizable (RSF1010 and ColE1) plasmids. The change in specificity was due to a loss of some amino acids in the carboxyl terminus of TraD that resulted in a broadening of the range of mobilizable relaxosomes at the expense of a decrease in the efficiency of F-plasmid transfer.

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32

WADA, Chieko. "Control of initiation of F plasmid replication." Seibutsu Butsuri 28, no. 5 (1988): 250–54. http://dx.doi.org/10.2142/biophys.28.250.

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33

Hiraga, S., A. Jaffé, T. Ogura, H. Mori, and H. Takahashi. "F plasmid ccd mechanism in Escherichia coli." Journal of Bacteriology 166, no. 1 (1986): 100–104. http://dx.doi.org/10.1128/jb.166.1.100-104.1986.

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34

Womble, David D., and Robert H. Rownd. "Regulation of mini-F plasmid DNA replication." Journal of Molecular Biology 195, no. 1 (1987): 99–113. http://dx.doi.org/10.1016/0022-2836(87)90330-5.

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35

Kline, Bruce C. "A review of mini-F plasmid maintenance." Plasmid 14, no. 1 (1985): 1–16. http://dx.doi.org/10.1016/0147-619x(85)90027-7.

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36

Sengupta, Manjistha, Henrik Jorck Nielsen, Brenda Youngren, and Stuart Austin. "P1 Plasmid Segregation: Accurate Redistribution by Dynamic Plasmid Pairing and Separation." Journal of Bacteriology 192, no. 5 (2009): 1175–83. http://dx.doi.org/10.1128/jb.01245-09.

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ABSTRACT Low-copy-number plasmids, such as P1 and F, encode a type Ia partition system (P1par or Fsop) for active segregation of copies to daughter cells. Typical descriptions show a single central plasmid focus dividing and the products moving to the cell quarter regions, ensuring segregation. However, using improved optical and analytical tools and large cell populations, we show that P1 plasmid foci are very broadly distributed. Moreover, under most growth conditions, more than two foci are frequently present. Each focus contains either one or two plasmid copies. Replication and focus splitting occur at almost any position in the cell. The products then move rapidly apart for approximately 40% of the cell length. They then tend to maintain their relative positions. The segregating foci often pass close to or come to rest close to other foci in the cell. Foci frequently appear to fuse during these encounters. Such events occur several times in each cell and cell generation on average. We argue that foci pair with their neighbors and then actively separate again. The net result is an approximately even distribution of foci along the long cell axis on average. We show mathematically that trans-pairing and active separation could greatly increase the accuracy of segregation and would produce the distributions of foci that we observe. Plasmid pairing and separation may constitute a novel fine-tuning mechanism that takes the basic pattern created when plasmids separate after replication and converts it to a roughly even pattern that greatly improves the fidelity of plasmid segregation.

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37

Bates, Steven, Annette M. Cashmore, and Brian M. Wilkins. "IncP Plasmids Are Unusually Effective in Mediating Conjugation of Escherichia coli and Saccharomyces cerevisiae: Involvement of the Tra2 Mating System." Journal of Bacteriology 180, no. 24 (1998): 6538–43. http://dx.doi.org/10.1128/jb.180.24.6538-6543.1998.

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ABSTRACT Mobilizable shuttle plasmids containing the origin-of-transfer (oriT) region of plasmids F (IncFI), ColIb-P9 (IncI1), and RP4/RP1 (IncPα) were constructed to test the ability of the cognate conjugation system to mediate gene transfer from Escherichia coli to Saccharomyces cerevisiae. Only the Pα system caused detectable mobilization to yeast, giving peak values of 5 × 10−5 transconjugants per recipient cell in 30 min. Transfer of the shuttle plasmid required carriage oforiT in cis and the provision intrans of the Pα Tra1 core and Tra2 core regions. Genes outside the Tra1 core did not increase the mobilization efficiency. All 10 Tra2 core genes (trbB, -C, -D, -E, -F, -G, -H, -I, -J, and -L) required for plasmid transfer to E. coli K-12 were needed for transfer to yeast. To assess whether the mating-pair formation (Mpf) system or DNA-processing apparatus of the Pα conjugation system is critical in transkingdom transfer, an assay using an IncQ-based shuttle plasmid specifying its own DNA-processing system was devised. RP1 but not ColIb mobilized the construct to yeast, indicating that the Mpf complex determined by the Tra2 core genes plus traF is primarily responsible for the remarkable fertility of the Pα system in mediating gene transfer from bacteria to eukaryotes.

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38

Harris, Robin L., K. April Sholl, Michael N. Conrad, Michael E. Dresser, and Philip M. Silverman. "Interaction between the F plasmid TraA (F-pilin) and TraQ proteins." Molecular Microbiology 34, no. 4 (1999): 780–91. http://dx.doi.org/10.1046/j.1365-2958.1999.01640.x.

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39

Venderbure, Claude, Arnaud Chastanet, François Boudsocq, Suzanne Sommer, and Adriana Bailone. "Inhibition of Homologous Recombination by the Plasmid MucA′B Complex." Journal of Bacteriology 181, no. 4 (1999): 1249–55. http://dx.doi.org/10.1128/jb.181.4.1249-1255.1999.

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ABSTRACT By its functional interaction with a RecA polymer, the mutagenic UmuD′C complex possesses an antirecombination activity. We show here that MucA′B, a functional homolog of the UmuD′C complex, inhibits homologous recombination as well. In F− recipients expressing MucA′B from a P tac promoter, Hfr × F−recombination decreased with increasing MucA′B concentrations down to 50-fold. In damage-induced pKM101-containing cells expressing MucA′B from the native promoter, recombination between a UV-damaged F lac plasmid and homologous chromosomal DNA decreased 10-fold. Overexpression of MucA′B together with UmuD′C resulted in a synergistic inhibition of recombination. RecA[UmuR] proteins, which are resistant to UmuD′C inhibition of recombination, are inhibited by MucA′B while promoting MucA′B-promoted mutagenesis efficiently. The data suggest that MucA′B and UmuD′C contact a RecA polymer at distinct sites. The MucA′B complex was more active than UmuD′C in promoting UV mutagenesis, yet it did not inhibit recombination more than UmuD′C does. The enhanced mutagenic potential of MucA′B may result from its inherent superior capacity to assist DNA polymerase intrans-lesion synthesis. In the course of this work, we found that the natural plasmid pKM101 expresses around 45,000 MucA and 13,000 MucB molecules per lexA(Def) cell devoid of LexA. These molecular Muc concentrations are far above those of the chromosomally encoded Umu counterparts. Plasmid pKM101 belongs to a family of broad-host-range conjugative plasmids. The elevated levels of the Muc proteins might be required for successful installation of pKM101-like plasmids into a variety of host cells.

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40

Slavcev, Roderick A., and Barbara E. Funnell. "Identification and Characterization of a Novel Allele of Escherichia coli dnaB Helicase That Compromises the Stability of Plasmid P1." Journal of Bacteriology 187, no. 4 (2005): 1227–37. http://dx.doi.org/10.1128/jb.187.4.1227-1237.2005.

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ABSTRACT Bacteriophage P1 lysogenizes Escherichia coli cells as a plasmid with approximately the same copy number as the copy number of the host chromosome. Faithful inheritance of the plasmids relies upon proper DNA replication, as well as a partition system that actively segregates plasmids to new daughter cells. We genetically screened for E. coli chromosomal mutations that influenced P1 stability and identified a novel temperature-sensitive allele of the dnaB helicase gene (dnaB277) that replaces serine 277 with a leucine residue (DnaB S277L). This allele conferred a severe temperature-sensitive phenotype to the host; dnaB277 cells were not viable at temperatures above 34°C. Shifting dnaB277 cells to 42°C resulted in an immediate reduction in the rate of DNA synthesis and extensive cell filamentation. The dnaB277 allele destabilized P1 plasmids but had no significant influence on the stability of the F low-copy-number plasmid. This observation suggests that there is a specific requirement for DnaB in P1 plasmid maintenance in addition to the general requirement for DnaB as the replicative helicase during elongation.

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41

Taylor, Diane E., and Elisa C. Brose. "Characterization of incompatibility group HI1 plasmids from Salmonella typhi by restriction endonuclease digestion and hybridization of DNA probes for Tn3, Tn9, and Tn10." Canadian Journal of Microbiology 31, no. 8 (1985): 721–29. http://dx.doi.org/10.1139/m85-136.

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Chloramphenicol resistance in Salmonella typhi is mediated by plasmids of the incompatibility group H, subgroup 1 (IncHI1). Eight IncHI1 plasmids from S. typhi strains originating in Mexico, Vietnam, Thailand, and India were examined by restriction enzyme digestion. The restriction enzymes, ApaI, XbaI, and PstI were found to be most useful for comparison of plasmid DNAs. Four plasmids from S. typhi isolated in Mexico, Vietnam, and Thailand between 1972 and 1974 had identical restriction patterns with all three enzymes. The other IncHI1 plasmids showed only minor differences. However, some significant differences were noted between these IncHI1 plasmids and the prototype IncHI1 plasmid R27, which was isolated from S. typhimurium in 1961 and for which a restriction map has been constructed. Southern transfer hybridization with a nick-translated HI1 plasmid as a probe confirmed that there is a great deal of sequence homology among the IncHI1 plasmids. DNA probes were used to locate DNA sequences for ampicillin resistance (Tn3), chloramphenicol resistance (Tn9), tetracycline resistance (Tn10), and the one-way incompatibility between IncHI1 plasmids and the F factor, a characteristic property of IncHI1 plasmids. The results demonstrate that IncHI1 plasmids isolated from S. typhi from widely different geographic sources are very similar. Comparisons between the S. typhi plasmids and R27 indicated that conserved regions of DNA were those involved in conjugative transfer.

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42

Sharma, Suveena, Bangalore K. Sathyanarayana, Jeremy G. Bird, Joel R. Hoskins, Byungkook Lee, and Sue Wickner. "Plasmid P1 RepA Is Homologous to the F Plasmid RepE Class of Initiators." Journal of Biological Chemistry 279, no. 7 (2003): 6027–34. http://dx.doi.org/10.1074/jbc.m310917200.

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43

Yoshioka, Y., H. Ohtsubo, and E. Ohtsubo. "Repressor gene finO in plasmids R100 and F: constitutive transfer of plasmid F is caused by insertion of IS3 into F finO." Journal of Bacteriology 169, no. 2 (1987): 619–23. http://dx.doi.org/10.1128/jb.169.2.619-623.1987.

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44

Takai, Shinji, Masato Shoda, Yukako Sasaki, et al. "Restriction Fragment Length Polymorphisms of Virulence Plasmids in Rhodococcus equi." Journal of Clinical Microbiology 37, no. 10 (1999): 3417–20. http://dx.doi.org/10.1128/jcm.37.10.3417-3420.1999.

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Virulent Rhodococcus equi, which is a well-known cause of pyogranulomatous pneumonia in foals, possesses a large plasmid encoding virulence-associated 15- to 17-kDa antigens. Foal and soil isolates from five countries—Argentina, Australia, Canada, France, and Japan—were investigated for the presence of 15- to 17-kDa antigens by colony blotting, using the monoclonal antibody 10G5, and the gene coding for 15- to 17-kDa antigens by PCR. Plasmid DNAs extracted from positive isolates were digested with restriction endonucleasesBamHI, EcoRI, EcoT22I, andHindIII, and the digestion patterns that resulted divided the plasmids of virulent isolates into five closely related types. Three of the five types had already been reported in Canadian and Japanese isolates, and the two new types had been found in French and Japanese isolates. Therefore, we tentatively designated these five types 85-kb type I (pREAT701), 85-kb type II (a new type), 87-kb type I (EcoRI and BamHI type 2 [V. M. Nicholson and J. F. Prescott, J. Clin. Microbiol. 35:738–740, 1997]), 87-kb type II (a new type), and 90-kb (pREL1) plasmids. The 85-kb type I plasmid was found in isolates from Argentina, Australia, Canada, and France. Plasmid 87-kb type I was isolated in specimens from Argentina, Canada, and France. The 85-kb type II plasmid appeared in isolates from France. On the other hand, plasmids 87-kb type II and 90-kb were found only in isolates from Japan. These results revealed geographic differences in the distribution of the virulence plasmids found in the five countries and suggested that the restriction fragment length polymorphism of virulence plasmids might be useful to elucidate the molecular epidemiology of virulent R. equi in the world.

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45

Fu, Y. H., M. M. Tsai, Y. N. Luo, and R. C. Deonier. "Deletion analysis of the F plasmid oriT locus." Journal of Bacteriology 173, no. 3 (1991): 1012–20. http://dx.doi.org/10.1128/jb.173.3.1012-1020.1991.

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46

Tam, J. E., and B. C. Kline. "Control of the ccd operon in plasmid F." Journal of Bacteriology 171, no. 5 (1989): 2353–60. http://dx.doi.org/10.1128/jb.171.5.2353-2360.1989.

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47

Manwaring, Neil P., Ronald A. Skurray, and Neville Firth. "Nucleotide Sequence of the F Plasmid Leading Region." Plasmid 41, no. 3 (1999): 219–25. http://dx.doi.org/10.1006/plas.1999.1390.

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48

Fowler, Tim, and Russell Thompson. "Shadow promoters in the F plasmid transfer operon." Molecular and General Genetics MGG 202, no. 3 (1986): 509–11. http://dx.doi.org/10.1007/bf00333285.

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49

Arutyunov, Denis, Barbara Arenson, Jan Manchak, and Laura S. Frost. "F Plasmid TraF and TraH Are Components of an Outer Membrane Complex Involved in Conjugation." Journal of Bacteriology 192, no. 6 (2010): 1730–34. http://dx.doi.org/10.1128/jb.00726-09.

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ABSTRACT F plasmid TraF and TraH are required for F pilus assembly and F plasmid transfer. Using flotation sucrose density gradients, we found that TraF and TraH (as well as TraU and TraW) localized to the outer membrane in the presence of the complete F transfer region, especially TraV, the putative anchor. Mutational analysis of TraH revealed two domains that are important for its function and possible interaction with TrbI, which in turn has a role in stabilizing TraH.

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50

Peng, Yun, Jun Lu, Joyce J. W. Wong, Ross A. Edwards, Laura S. Frost, and J. N. Mark Glover. "Mechanistic Basis of Plasmid-Specific DNA Binding of the F Plasmid Regulatory Protein, TraM." Journal of Molecular Biology 426, no. 22 (2014): 3783–95. http://dx.doi.org/10.1016/j.jmb.2014.09.018.

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