Plasmid (Plasmid)

Publisher: Elsevier

Journal description

Plasmid, A Journal of Molecular Genetics with Emphasis on Plasmid Biology, is a premier journal in the field of molecular microbiology and biotechnology. The journal focuses on the biology of extrachromosomal genetic elements in both prokaryotic and eukaryotic systems, including their biological behavior, molecular structure, genetic function, gene products, and use as genetic tools. The journal features original research reports on movable genetic elements in prokaryotes and in eukaryotes, and publishes minireviews on various aspects of extrachromosomal gene systems and molecular microbiology.

Current impact factor: 1.58

Impact Factor Rankings

2015 Impact Factor Available summer 2016
2014 Impact Factor 1.578
2013 Impact Factor 1.76
2012 Impact Factor 1.276
2011 Impact Factor 1.516
2010 Impact Factor 1.798
2009 Impact Factor 1.816
2008 Impact Factor 1.255
2007 Impact Factor 2.041
2006 Impact Factor 1.956
2005 Impact Factor 1.446
2004 Impact Factor 1.542
2003 Impact Factor 1.406
2002 Impact Factor 1.495
2001 Impact Factor 1.573
2000 Impact Factor 1.302
1999 Impact Factor 1.463
1998 Impact Factor 1.319
1997 Impact Factor 1.38
1996 Impact Factor 1.611
1995 Impact Factor 1.421
1994 Impact Factor 1.744
1993 Impact Factor 1.657
1992 Impact Factor 1.423

Impact factor over time

Impact factor

Additional details

5-year impact 1.61
Cited half-life >10.0
Immediacy index 0.31
Eigenfactor 0.00
Article influence 0.54
Website Plasmid website
Other titles Plasmid (Online), Plasmid
ISSN 1095-9890
OCLC 36951394
Material type Document, Periodical, Internet resource
Document type Internet Resource, Computer File, Journal / Magazine / Newspaper

Publisher details


  • Pre-print
    • Author can archive a pre-print version
  • Post-print
    • Author can archive a post-print version
  • Conditions
    • Authors pre-print on any website, including arXiv and RePEC
    • Author's post-print on author's personal website immediately
    • Author's post-print on open access repository after an embargo period of between 12 months and 48 months
    • Permitted deposit due to Funding Body, Institutional and Governmental policy or mandate, may be required to comply with embargo periods of 12 months to 48 months
    • Author's post-print may be used to update arXiv and RepEC
    • Publisher's version/PDF cannot be used
    • Must link to publisher version with DOI
    • Author's post-print must be released with a Creative Commons Attribution Non-Commercial No Derivatives License
    • Publisher last reviewed on 03/06/2015
  • Classification
    ​ green

Publications in this journal

  • [Show abstract] [Hide abstract]
    ABSTRACT: The Bacillus pumilus 15.1 strain, a recently described entomopathogenic strain active against Ceratitis capitata, contains at least two extrachromosomal elements, pBp15.1S and pBp15.1B. Given that B. pumilus is not a typical entomopathogenic bacterium, the acquisition of this extrachromosomal DNA may explain why B. pumilus 15.1 is toxic to an insect. One of the plasmids present in the strain, the pBp15.1S plasmid, was sub-cloned, sequenced and analyzed using bioinformatics to identify any potential virulence factor. The pBp15.1S plasmid was found to be 7785bp in size with a GC content of 35.7% and 11 putative ORFs. A replication module typical of small rolling circle plasmid and a sensing and regulatory system specific for plasmids was found in pBp15.1S. Additionally, we demonstrated the existence of ssDNA in plasmid preparations suggesting that pBp15.1S replicates by the small rolling circle mechanism. A gene cluster present in plasmid pPZZ84 from a distantly isolated B. pumilus strain was also present in pBp15.1S. The plasmid copy number of pBp15.1S in exponentially growing B. pumilus cells was determined to be 33 copies per chromosome. After an extensive plasmid characterization, no known virulence factor was found so a search in the other extrachromosomal elements of the bacteria is needed.
    Plasmid 09/2015; DOI:10.1016/j.plasmid.2015.09.001
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    ABSTRACT: Serine/arginine-rich splicing factor-3 (SRSF3), alternatively known as SRp20, is a member of the highly-conserved SR protein family of mRNA splicing factors. SRSF3 generally functions as an enhancer of mRNA splicing by binding to transcripts in a sequence-specific manner to both recruit and stabilize the binding of spliceosomal components to the mRNA. In liver, expression of SRSF3 is relatively low and its activity is increased in response to insulin and feeding a high carbohydrate diet. We sought to over-express SRSF3 in primary rat hepatocytes to identify regulatory targets. A standard adenoviral shuttle vector system containing an epitope-tagged SRSF3 under the transcriptional control of the CMV promoter could not be used to produce infectious adenoviral particles. SRSF3 over-expression in the packaging cell line prevented the production of infectious adenovirus particles by interfering with the viral splicing program. To circumvent this issue, SRSF3 expression from the shuttle vector was blocked by placing its expression under the control of the liver-specific albumin promoter. In this system, the FLAG-SRSF3 transgene is only expressed in the target cells (hepatocytes) but not in the packaging cell line. An additional benefit of the albumin promoter is that expression of the transgene does not require the addition of hormones or antibiotics to drive SRSF3 expression in the hepatocytes. Robust expression of FLAG-SRSF3 protein is detected in both HepG2 cells and primary rat hepatocytes infected with adenovirus prepared from this new shuttle vector. Furthermore, abundances of several known and suspected mRNA targets of SRSF3 action are increased in response to over-expression using this virus. This report details the construction of the albumin promoter-driven adenoviral shuttle vector, termed pmAlbAd5-FLAG.SRSF3, that can be used to generate functional adenovirus to express FLAG-SRSF3 specifically in liver. This vector would be suitable for over-expression of other splicing factors that could inhibit virus production. In addition, this vector would allow only liver-specific expression of other cargo genes when used in a whole-animal paradigm. Copyright © 2015. Published by Elsevier Inc.
    Plasmid 08/2015; 82. DOI:10.1016/j.plasmid.2015.07.004
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    ABSTRACT: CTnDOT is a 65kbp integrative and conjugative element (ICE) that carries genes encoding both tetracycline and erythromycin resistances. The Excision operon of this element encodes Xis2c, Xis2d, and Exc proteins involved in the excision of CTnDOT from host chromosomes. These proteins are also required in the complex transcriptional regulation of the divergently transcribed transfer (tra) and mobilization (mob) operons of CTnDOT. Transcription of the tra operon is positively regulated by Xis2c and Xis2d, whereas, transcription of the mob operon is positively regulated by Xis2d and Exc. Xis2d is the only protein that is involved in the excision reaction, as well as the transcriptional regulation of both the mob and tra operons. This paper helps establish how Xis2d binds the DNA in the mob and tra region. Unlike other excisionase proteins, Xis2d binds a region of dyad symmetry. The binding site is located in the intergenic region between the mob and tra promoters, and once bound Xis2d induces a bend in the DNA. Xis2d binding to this region could be the preliminary step for the activation of both operons. Then the other proteins, like Exc, can interact with Xis2d and form higher order complexes. Copyright © 2015. Published by Elsevier Inc.
    Plasmid 07/2015; 81. DOI:10.1016/j.plasmid.2015.07.002
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    ABSTRACT: Presence of natural plasmids has been reported for many Shewanella isolates. However, knowledge about plasmid replication origin and segregation mechanisms is not extensive for this genus. Shewanella baltica is an important species in the marine environment due to its denitrification ability in oxygen-deficient zones and the potential role in bioremediation processes. However, no information about possible use of plasmid vectors in this species has been reported to date. Here we report that plasmids with ColE1-type and plasmid P1 origin can transform S. baltica and replicate in this bacterium. Without the antibiotic selection pressure plasmid maintenance is less efficient than in Escherichia coli. Nevertheless, cultivation of S. baltica in the presence of appropriate antibiotics caused relatively stable maintenance of ColE1-like and P1-derived plasmids. This indicates that plasmid-based genetic manipulations and gene transfer in S. baltica is possible. Copyright © 2015. Published by Elsevier Inc.
    Plasmid 07/2015; 81. DOI:10.1016/j.plasmid.2015.07.001
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    ABSTRACT: Although several plasmids have been used in Listeria monocytogenes for generating mutants by allelic exchange, construction of L. monocytogenes mutants has been inefficient due to lack of effective selection markers for first and second recombination events. To address this problem, we have developed a new suicide plasmid, pHoss1, by using the pMAD plasmid backbone and anhydrotetracycline selection marker (secY antisense RNA) driven by an inducible Pxyl/tetO promoter. Expression of the secY antisense RNA eliminates merodiploids and selects for the loss of plasmid via a second allelic exchange, which enriches the number of mutants with deleted genes. To assess the effectiveness of pHoss1 for the generation of stable in-frame deletion mutations, the ispG and ispH genes of L. monocytogenes serotype 4b strain F2365 were deleted. Results showed that identification of the second allelic exchange mutants was very efficient with 80-100% of the colonies yielding desired deletion mutants. L. monocytogenes' intestinal cell attachment was not altered when ispG and ispH genes were deleted. We expect that this new plasmid will be very useful for construction of marker-free deletion mutants in L. monocytogenes, and in other Gram-positive bacteria, including Staphylococcus aureus and Bacillus cereus. Copyright © 2015. Published by Elsevier Inc.
    Plasmid 05/2015; 81. DOI:10.1016/j.plasmid.2015.05.003
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    ABSTRACT: Plasmids belonging to incompatibility groups A and C (now A/C) were among the earliest to be associated with antibiotic resistance in Gram-negative bacteria. A/C plasmids are large, conjugative plasmids with a broad host range. The prevalence of A/C plasmids in collections of clinical isolates has revealed their importance in the dissemination of extended-spectrum β-lactamases and carbapenemases. They also mobilize SGI1-type resistance islands. Revived interest in the family has yielded many complete A/C plasmid sequences, revealing that RA1, designated A/C1, is different from the remainder, designated A/C2. There are two distinct A/C2 lineages. Backbones of 128-130 kb include over 120 genes or ORFs encoding proteins of at least 100 amino acids, but very few have been characterized. Genes potentially required for replication, stability and transfer have been identified, but only the replication system of RA1 and the regulation of transfer have been studied. There is enormous variety in the antibiotic resistance genes carried by A/C2 plasmids but they are usually clustered in larger regions at various locations in the backbone. The ARI-A and ARI-B resistance islands are always at a specific location but have variable content. ARI-A is only found in type 1 A/C2 plasmids, which disseminate blaCMY-2 and blaNDM-1 genes, whereas ARI-B, carrying the sul2 gene, is found in both type 1 and type 2. This review summarizes current knowledge of A/C plasmids, and highlights areas of research to be considered in the future. Copyright © 2015. Published by Elsevier Inc.
    Plasmid 04/2015; 80. DOI:10.1016/j.plasmid.2015.04.003
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    ABSTRACT: We studied the detailed structure of the cryptic plasmid pIGWZ12, which was isolated from an Escherichia coli strain. pIGWZ12 is composed of two structural modules of distinct evolutionary origin. The REP module, which contains all the features necessary for replication and stable maintenance in the bacterial cell, was assigned by genotyping to the IncF family. The MOB module, which is responsible for plasmid mobilization, shows significant homology to MOBQ modules from broad-host-range plasmids belonging to the RSF1010/R1162 family. We showed that iterons located in the origin of replication are the target for specific binding by the replication initiator protein RepApIGWZ12. Furthermore, we proved that the promoter for the repA gene overlaps with the iterons, and that the latter are the sole determinant of incompatibility. We performed a mutagenesis analysis of the MOBpIGWZ12 module and characterized the roles played by all identified genes (mobA and mobC), as well as the role played by oriT in mobilization. Finally, we showed that it was possible to remove the MOB module from pIGWZ12 without any loss in plasmid replication and stability. Furthermore, the MOBpIGWZ12 module was fully functional after subcloning into another plasmid. Therefore, pIGWZ12 is yet another example of modular structure in small cryptic plasmids. Copyright © 2015. Published by Elsevier Inc.
    Plasmid 04/2015; 79. DOI:10.1016/j.plasmid.2015.04.001
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    ABSTRACT: A cryptic plasmid, pJY33, from Weissella cibaria 33 was characterized. pJY33 was 2,365 bp in size with a GC content of 41.27% and contained two putative open reading frames (ORFs). orf1 encoded a putative hypothetical protein of 134 amino acids. orf2 was 849 bp in size, and its putative translation product exhibited 87% identity with a replication initiation factor from a plasmid from W. cibaria KLC140. A Weissella-Escherichia coli shuttle vector, pJY33E (6.5 kb, Em(r)), was constructed by ligation of pJY33 with pBluescript II SK(-) and an erythromycin resistance gene (Em(r)). pJY33E replicated in Lactococcus lactis, Leuconostoc citreum, Lactobacillus brevis, Lactobacillus plantarum, and Weissella confusa. A single-stranded DNA intermediate was detected from Lb. brevis 2.14 harbouring pJY33E, providing evidence for rolling-circle replication of pJY33. Most Lb. brevis 2.14 cells (85.9%) retained pJY33E after one week of daily culturing in MRS broth without Em. An aga gene encoding α-galactosidase (α-Gal) from Leuconostoc mesenteroides was successfully expressed in Lb. brevis 2.14 using pJY33E, and the highest level of α-Gal activity (36.13 U/mg protein) was observed when cells were grown on melibiose. Copyright © 2015. Published by Elsevier Inc.
    Plasmid 04/2015; 79. DOI:10.1016/j.plasmid.2015.03.008
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    ABSTRACT: A collection of 111 commensal Escherichia coli isolated from 84 faecal samples from healthy Australian adults were screened using PCR-based replicon typing. Each isolate represented a distinct strain found in a particular faecal sample. 51 isolates were resistant to one or more of 12 antibiotics tested. FII and FIB replicons were most common and usually found together. The FII replicon was detected in 63 isolates (35 susceptible, 28 resistant), the FIB replicon was present in 65 (32 susceptible, 33 resistant) and 54 (30 susceptible, 24 resistant) included both. Other replicon types were found infrequently (A/C, I1, K, L/M, P, R, Y, FIA and FIC) or not at all (HI1, HI2, N, T, U, W, X). Only the B/O amplicon, found in 21 resistant but only 4 susceptible isolates, was associated with antibiotic resistance. Detailed analysis of this group revealed that the B/O PCR also detected Z plasmids of several distinguishable types. PCR assays were developed to detect the two repA genes (repABKI and repAZ) found in members of the I-complex (I, B/O, K and Z plasmids). These assays distinguished the B/O and Z plasmids detected by the original "B/O" PCR. One isolate carried repABKI and the remainder carried repAZ. These genes were also detected in further isolates in the collection. Conjugative transfer of resistance genes was detected for the B/O plasmid and two Z groups. Evidence for transfer of repAZ plasmids in the human colon in the absence of antibiotic selection was also obtained. Copyright © 2015. Published by Elsevier Inc.
    Plasmid 03/2015; 80. DOI:10.1016/j.plasmid.2015.03.005
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    ABSTRACT: We sequenced the complete 7118 bp circular plasmid pColE3-CA38 (pColE3) from Escherichia coli, located the previously identified colicin components together with two new ORFs that have homology to mobilization and transfer proteins, and found that pColE3 is highly similar to a plasmid present in enterohemorrhagic E. coli O111. We also found that unusual aspects of the plasmid include the inability to be completely digested with restriction endonucleases and asymmetric Phred DNA sequencing quality scores, with significantly lower scores in the forward direction relative to the colicin and immunity proteins consistent with plus (+) strand DNA. Comparing the A260 with picogreen double-stranded DNA (dsDNA) fluorescence and oligreen single-stranded DNA (ssDNA) fluorescence as well as metachromatic staining by acridine orange, we found that the undigested pColE3 DNA stains preferentially as ssDNA and that it coexists with dsDNA. We also identified ssDNA in pColE5 and pColE9 but not in pColE1. Colicin plasmids producing ssDNA may represent a new subclass of rolling-circle replication plasmids and add to the known similarities between colicins and filamentous phage.
    Plasmid 11/2014; 77. DOI:10.1016/j.plasmid.2014.11.001
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    ABSTRACT: The 89,977 bp nucleotide sequence of pACM1, isolated from a 1993 outbreak strain of cephalosporin-resistant Klebsiella oxytoca, has been completed and assigned GenBank accession number KJ541681. The plasmid has a single 31,842 bp mosaic multi-drug resistance-encoding (MDR) region comprising the mer resistance module of Tn1696, 2 integrons with a total of 7 cassettes, one complete copy each of IS1R and IS26, and the bla(SHV-5)-carrying Tn2003 (with defective IS26 termini), all within a Tn1721-like element inserted into the mucB gene of the IncL/M plasmid backbone. The Tn1721-Tn1696 combination resembles sequence found in the chromosomal MDR islands of some Acinetobacter baumannii isolates. Among the completely sequenced IncL/M resistance plasmids, the Tn1721-based MDR region is unique, but data from older studies suggest that this type of plasmid was widespread in the 1990s. Since resistance gene dosage is affected by plasmid copy number (PCN), we used a relatively simple new "efficiency-corrected" qPCR assay to measure the PCN of pACM1. There are approximately 3 copies per chromosome in an E. coli DH5α host, and 2 in the original K. oxytoca isolate. We could not find similar PCN data for other medically important plasmids for comparison. The study of this plasmid property and its effect on resistance levels should be facilitated in the future by the availability of qPCR instruments and complete genome sequences.
    Plasmid 10/2014; 76. DOI:10.1016/j.plasmid.2014.08.005
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    ABSTRACT: A mammary gland-specific expression vector p205C3 was constructed with the 5'- and 3'-flanking regions of β-lactoglobulin gene and the first intron of β-casein gene of Chinese dairy goat as regulatory sequences. Human lysozyme (hLYZ) cDNA from mammary gland was cloned into p205C3 and the recombinant vector was used to generate transgenic mice by microinjection. Based on the lysoplate assay, four female offspring of one male founder were detected expressing recombinant hLYZ in their milk at the levels of 5-200 mg/L, and the expressed protein had the same molecular weight as that of normal hLYZ. Besides mammary glands, ectopic expressions were also found in the spleens and the small intestines of the transgenic mice. Among the offspring, the female transgenic mice maintained and expressed the transgene stably with a highest expression level of 750 mg/L. Therefore, p205C3 could be used to develop animal mammary gland bioreactors expressing hLYZ.
    Plasmid 09/2014; 76. DOI:10.1016/j.plasmid.2014.09.004
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    ABSTRACT: In the last decade regulatory RNAs have emerged as powerful tools to regulate the expression of genes both in prokaryotes and in eukaryotes. RNases, by degrading these RNA molecules, control the right amount of the regulatory RNAs, which is fundamental for an accurate regulation of gene expression in the cell. Remarkably the first antisense RNAs identified were plasmid-encoded and their detailed study was crucial for the understanding of prokaryotic antisense RNAs. In this review we highlight the role of RNases in the precise modulation of antisense RNAs that control plasmid replication, maintenance and transfer.
    Plasmid 09/2014; 78. DOI:10.1016/j.plasmid.2014.09.003
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    ABSTRACT: This article describes a rapid, highly efficient and versatile method for seamlessly assembling multiple DNA fragments into a vector at any desired position. The inserted fragments and vector backbone were amplified by high-fidelity PCR containing 20 bp to 50 bp overlapping regions at 3' and/or 5' termini. These linearised fragments were equimolarly mixed, and then cyclised in a prolonged overlap extension PCR without adding primers. The resulting PCR products were DNA multimers that could be directly transformed into host strains, yielding the desired chimeric plasmid. The proposed method was illustrated by constructing an Escherichia coli co-expression vector. The feasibility of the method in Lactobacillus was further validated by assembling an E. coli-Lactobacillus shuttle vector. Results showed that three to four fragments could be simultaneously and precisely inserted in a vector in only two to three days using the proposed method. The acceptable transformation efficiency was determined through the tested host strains; more than 95% of the colonies were positive transformants. Therefore, the proposed method is sufficiently competent for high-efficiency insertion of multiple DNA fragments into a plasmid and has theoretically good application potential for gene cloning and protein expression because it is simple, easy to implement, flexible and yields highly positive clones.
    Plasmid 09/2014; 76. DOI:10.1016/j.plasmid.2014.09.002
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    ABSTRACT: Horizontal gene transfer plays an important role in the evolution of bacterial species, conferring new genetic traits on the recipient bacterium that extend its range of phenotypes and plasmids make important contributions to this process. However, the inappropriate expression of newly acquired genes may lead to a loss of competitive fitness, resulting in the elimination of the new gene-bacterium combination. It is thought that transcriptional silencing of horizontally acquired genes offers a route out of this dilemma and that nucleoid-associated proteins, especially those related to the H-NS protein, play a particularly important role in the silencing process. The discovery that many plasmids express orthologues of nucleoid-associated proteins adds an interesting dimension to current models of regulatory integration following lateral transfer of DNA. Other horizontally acquired genetic elements, such as genomic islands, also express nucleoid-associated proteins of their own. Here the interactions of H-NS-like nucleoid-associated proteins encoded by the core genome, genomic islands and plasmids are described.
    Plasmid 09/2014; 75. DOI:10.1016/j.plasmid.2014.06.004