Read by QxMD icon Read


Marc J A Stevens, Adriano Venturini, Christophe Lacroix, Leo Meile
Bifidobacterium thermophilum is encountered in the GI-tract of pigs and infants. Here we provide a transformation protocol for B. thermophilum and a novel expression vector for this species. The protocol resulted in transformation rates of 1×10(3) transformed cells per μg DNA. Transformation was shown to be dependent on the presence of fructo-oligosaccharides during growth, polyethylene glycol in the electroporation buffer, and on methylation of the vector. The Escherichia coli - B. thermophilum shuttle vector pLFB1012 for heterologous gene expression was constructed harbouring the glyceraldehyde 3-phosphate dehydrogenase promoter from Bifidobacterium longum (Pgap)...
July 13, 2017: Plasmid
Yan-Xian Yang, Yong-Qiang Yang, Chang-Wei Lei, Bi-Hui Liu, Wei Jiang, Hong-Ning Wang, Maria Consuelo Gazitúa, An-Yun Zhang
Recently, a novel variant of the CTX-M enzyme, CTX-M-98, was detected in Escherichia coli isolates from food animals. However, few plasmids carrying blaCTX-M-98 have been fully characterized. In this study, we sequenced the complete pHeBE7 plasmid, an 86,015-bp plasmid that contains the blaCTX-M-98b, blaTEM-1, rmtB, and traT genes, using whole-genome sequencing. The backbone of pHeBE7 shows a high similarity (>99%) to pMC-NDM, which carries the blaNDM-1 gene, however its mosaic regions remain relatively unique among sequenced plasmids...
July 6, 2017: Plasmid
Timothy L Haskett, Joshua P Ramsay, Amanuel A Bekuma, John T Sullivan, Graham W O'Hara, Jason J Terpolilli
Integrative and conjugative elements (ICEs) are generally regarded as regions of contiguous DNA integrated within a bacterial genome that are capable of excision and horizontal transfer via conjugation. We recently characterized a unique group of ICEs present in Mesorhizobium spp., which exist as three entirely separate but inextricably linked chromosomal regions termed α, β and γ. These regions occupy three different recombinase attachment (att) sites; however, they do not excise independently. Rather, they recombine the host chromosome to form a single contiguous region prior to excision and conjugative transfer...
June 29, 2017: Plasmid
Christopher J Harmer, Mohammad Hamidian, Ruth M Hall
The 167.5kb sequence of the conjugative IncC plasmid pIP40a, isolated from a Pseudomonas aeruginosa in 1969, was analysed. pIP40a confers resistance to kanamycin, neomycin, ampicillin, sulphonamides and mercuric ions, and several insertions in a type 1 IncC backbone were found, including copies of IS3, Tn1000 and a novel mercury resistance transposon, Tn6182. The antibiotic resistance genes were in two locations. Tn6023, containing the aphA1 kanamycin and neomycin resistance gene, is in a partial copy of Tn1/Tn2/Tn3 (blaTEM, ampicillin resistance) in the kfrA gene, and the sul2 sulphonamide resistance gene is in the integrative element GIsul2 in the position of ARI-B islands...
May 31, 2017: Plasmid
Karen E Preston, John A Tine
Within the IncM plasmid family there is a lineage that has a transposon Tn1721-based multiple-resistance island inserted in the backbone gene mucB. So far, this group includes R1215, p202c, pIGT15, pARM26, and pACM1, from Europe and the USA. A new member of this group, pACM130, was isolated at the same American hospital as pACM1 and has a similar resistance island, but also carries a copy of Tn1331 that interrupts the traY gene in the conjugation operon. The conjugative phenotype of this plasmid has been abolished, though pACM130 could be mobilized by an intact traY cloned into a laboratory vector and transformed into the same donor bacterium...
May 30, 2017: Plasmid
Longhua Hu, Anthony G Vecchiarelli, Kiyoshi Mizuuchi, Keir C Neuman, Jian Liu
No abstract text is available yet for this article.
May 18, 2017: Plasmid
Mostafa Aboulela, Yuji Tanaka, Kohji Nishimura, Shoji Mano, Tetsuya Kimura, Tsuyoshi Nakagawa
Analyses of the subcellular localization of proteins and protein-protein interaction networks are essential to uncover the molecular basis of diverse biological processes in plants. To this end, we have created a Gateway cloning-compatible vector system, named dual-site (DS) Gateway cloning system to allow simple cloning of two expression cassettes in a binary vector and to express them simultaneously in plant cells. In the DS Gateway cloning system, (i) a moderate constitutive nopaline synthase promoter (Pnos), which is much suitable for localization analysis, is used to guide each expression cassette, (ii) four series of vectors with different plant resistance markers are established, (iii) N-terminal fusion with 6 fluorescent proteins and 7 epitope tags is available, (iv) both N- and C-terminal fusions with split enhanced yellow fluorescent protein (EYFP) are possible for efficient detection of protein-protein interactions using a bimolecular fluorescence complementation (BiFC) assay...
May 9, 2017: Plasmid
Martin Werisch, Uta Berger, Thomas U Berendonk
Some plasmids can be transferred by conjugation to other bacterial hosts. But almost half of the plasmids are non-transmissible. These plasmid types can only be transmitted to the daughter cells of their host after bacterial fission. Previous studies suggest that non-transmissible plasmids become extinct in the absence of selection of their encoded traits, as plasmid-free bacteria are more competitive. Here, we aim to identify mechanisms that enable non-transmissible plasmids to persist, even if they are not beneficial...
April 28, 2017: Plasmid
James P J Hall, Michael A Brockhurst, Calvin Dytham, Ellie Harrison
Conjugative plasmids are widespread and play an important role in bacterial evolution by accelerating adaptation through horizontal gene transfer. However, explaining the long-term stability of plasmids remains challenging because segregational loss and the costs of plasmid carriage should drive the loss of plasmids though purifying selection. Theoretical and experimental studies suggest two key evolutionary routes to plasmid stability: First, the evolution of high conjugation rates would allow plasmids to survive through horizontal transmission as infectious agents, and second, compensatory evolution to ameliorate the cost of plasmid carriage can weaken purifying selection against plasmids...
April 28, 2017: Plasmid
Alex Orlek, Hang Phan, Anna E Sheppard, Michel Doumith, Matthew Ellington, Tim Peto, Derrick Crook, A Sarah Walker, Neil Woodford, Muna F Anjum, Nicole Stoesser
Plasmid typing can provide insights into the epidemiology and transmission of plasmid-mediated antibiotic resistance. The principal plasmid typing schemes are replicon typing and MOB typing, which utilize variation in replication loci and relaxase proteins respectively. Previous studies investigating the proportion of plasmids assigned a type by these schemes ('typeability') have yielded conflicting results; moreover, thousands of plasmid sequences have been added to NCBI in recent years, without consistent annotation to indicate which sequences represent complete plasmids...
May 2017: Plasmid
Luis Alfredo Bañuelos-Vazquez, Gonzalo Torres Tejerizo, Susana Brom
Horizontal gene transfer has been recognized as one of the principal contributors to bacterial evolution and diversification. One of the mechanisms involved in this process is conjugative transfer of plasmids and Integrative Conjugative Elements (ICEs). Plasmids and ICEs often encode traits beneficial for bacterial survival in specific environments, or for the establishment of symbiosis or pathogenesis, in addition to genes allowing conjugative transfer. In this review, we analyze the mechanisms that regulate the expression of conjugative transfer genes...
April 22, 2017: Plasmid
Lionel Makart, Florian Commans, Annika Gillis, Jacques Mahillon
pXO16, a large plasmid originating from Bacillus thuringiensis serovar israelensis, displays unique conjugation capacities: besides efficient self-transfer, it is able to mobilize and retro-mobilize non-conjugative plasmids, including those missing an oriT and/or a mob gene, also known as "non-mobilizable" plasmids. In this paper, another peculiar transfer property of pXO16 is described. This element is indeed able to transfer chromosomal loci at frequencies of ca. 10(-5)-10(-6) transconjugants/donor cell. Whereas most other chromosomal transfer systems occur via the integration of the conjugative elements into the chromosome prior to its transfer, pXO16 appears to transfer the chromosomal markers in the absence of physical integration, but rather through a "donation-type" mobilization...
April 20, 2017: Plasmid
Thomas D Watts, Priscilla A Johanesen, Dena Lyras, Julian I Rood, Vicki Adams
Clostridium perfringens produces an extensive repertoire of toxins and extracellular enzymes, many of which are intimately involved in the progression of disease and are encoded by genes on conjugative plasmids. In addition, many C. perfringens strains can carry up to five of these conjugative toxin or antimicrobial resistance plasmids, each of which has a similar 35kb backbone. This conserved backbone includes the tcp conjugation locus and the central control region (CCR), which encodes genes involved in plasmid regulation, replication and partitioning, including a parMRC partitioning locus...
April 6, 2017: Plasmid
Christopher M Thomas, Nicholas R Thomson, Ana M Cerdeño-Tárraga, Celeste J Brown, Eva M Top, Laura S Frost
Good annotation of plasmid genomes is essential to maximise the value of the rapidly increasing volume of plasmid sequences. This short review highlights some of the current issues and suggests some ways forward. Where a well-studied related plasmid system exists we recommend that new annotation adheres to the convention already established for that system, so long as it is based on sound principles and solid experimental evidence, even if some of the new genes are more similar to homologues in different systems...
March 30, 2017: Plasmid
Katherine E L Cox, Joel F Schildbach
The R1 antibiotic resistance plasmid, originally discovered in a clinical Salmonella isolate in London, 1963, has served for decades as a key model for understanding conjugative plasmids. Despite its scientific importance, a complete sequence of this plasmid has never been reported. We present the complete genome sequence of R1 along with a brief review of the current knowledge concerning its various genetic systems and a comparison to the F and R100 plasmids. R1 is 97,566 nucleotides long and contains 120 genes...
March 28, 2017: Plasmid
Adam C Brooks, Ling Chin Hwang
Bacterial plasmid and chromosome segregation systems ensure that genetic material is efficiently transmitted to progeny cells. Cell-based studies have shed light on the dynamic nature and the molecular basis of plasmid partition systems. In vitro reconstitutions, on the other hand, have proved to be an invaluable tool for studying the minimal components required to elucidate the mechanism of DNA segregation. This allows us to gain insight into the biological and biophysical processes that enable bacterial cells to move and position DNA...
March 18, 2017: Plasmid
Jessica A Wisniewski, Julian I Rood
The Gram-positive pathogen Clostridium perfringens possesses a family of large conjugative plasmids that is typified by the tetracycline resistance plasmid pCW3. Since these plasmids may carry antibiotic resistance genes or genes encoding extracellular or sporulation-associated toxins, the conjugative transfer of these plasmids appears to be important for the epidemiology of C. perfringens-mediated diseases. Sequence analysis of members of this plasmid family identified a highly conserved 35kb region that encodes proteins with various functions, including plasmid replication and partitioning...
March 7, 2017: Plasmid
Paula Bustamante, Jonathan R Iredell
The stable maintenance of certain plasmids in bacterial populations has contributed significantly to the current worldwide antibiotic resistance (AbR) emergency. IncX plasmids, long underestimated in this regard, have achieved recent notoriety for their roles in transmission of resistance to carbapenem and colistin, the last-line antibiotics for Gram-negative infections. Toxin-antitoxin (TA) systems contribute to stable maintenance of many AbR plasmids, and a few TA systems have been previously described in the IncX plasmids...
March 3, 2017: Plasmid
Yong Wang
Plasmids play essential roles in bacterial metabolism, evolution, and pathogenesis. The maintenance of plasmids is of great importance both scientifically and practically. In this mini-review, I look at the problem from a slightly different point of view and focus on the spatial distribution of high copy number plasmids, for which no active segregation mechanism has been identified. I review several distribution models and summarize the direct and indirect evidence in the literature, including the most recent progress on measuring the spatial distribution of high copy number plasmids using emerging super-resolution fluorescence microscopy...
March 2, 2017: Plasmid
Lilian A Lacerda, Lucia B Cavalca, Paula M M Martins, José S Govone, Maurício Bacci, Henrique Ferreira
Xanthomonas citri subsp. citri (X. citri) is a plant pathogen and the etiological agent of citrus canker, a severe disease that affects all the commercially important citrus varieties, and has worldwide distribution. Citrus canker cannot be healed, and the best method known to control the spread of X. citri in the orchards is the eradication of symptomatic and asymptomatic plants in the field. However, in the state of São Paulo, Brazil, the main orange producing area in the world, control is evolving to an integrated management system (IMS) in which growers have to use less susceptible plants, windshields to prevent bacterial spread out and sprays of cupric bactericidal formulations...
March 2017: Plasmid
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"