Plasmids: Current Research and Future Trends

"The editor presents eight reviews dealing with major areas in the research of plasmids. Each chapter ends with comprehensive references. Specialists as well as students receive an overview of the state of the art in plasmid research and receive ideas for progressing in their own research and education. ... All in all, this book written by leading practitioners in their specialty areas, is a core reference for students and research scientists in molecular biology and microbiology."

from Barbel Kiesel (Leipzig) in Eng. Life Sci. 2008, 8(4): 448

Further reading: Plasmids: Current Research and Future Trends

Labels: book review, plasmids

Plasmid DNA is becoming increasingly attractive for the delivery of therapeutic genes into human cells. The success of gene therapy depends on the efficient insertion of therapeutic genes at the appropriate chromosomal target sites within the human genome, without causing cell injury, oncogenic mutations or an immune response. The construction of plasmid vectors for this purpose is simple and straightforward. Custom-designed zinc finger nucleases that combine the non-specific cleavage domain of FokI endonuclease with zinc finger proteins offer a general way to deliver a site-specific double strand break to the genome, and stimulate local homologous recombination by several orders of magnitude. This makes targeted gene correction or genome editing a viable option in human cells. These plasmids can be used to transiently express zinc finger nucleases to target a double strand break to a specific gene locus in human cells; they offer an excellent way for targeted delivery of the therapeutic genes to a pre-selected chromosomal site. The plasmid-based approach has the potential to circumvent all the problems associated with the viral delivery of therapeutic genes.

from Kandavelou and Chandrasegaran in Plasmids: Current Research and Future Trends

Labels: plasmids, therapy

Writing in the journal Microbiology Today (Society for General Microbiology, UK), Andrew Spiers of the University of Abertay, UK, reviews a new book on Plasmids published by Caister Academic Press. His comments include:

"the very useful guide to bioinformatics (J.E. Grant & P. Stothard), an in-depth description of the molecular machinery of DNA translocation (S. Russi et al.) and a thoroughly excellent discussion of HGT (M. Sota & E.M. Top)"
For full details please visit Plasmids: Current Research and Future Trends

Labels: book review, plasmids

from George W. Sundin and Jesús Murillo in Plant Pathogenic Bacteria
The concept of bacterial plasmids as gene traders is illustrative of the role of plasmids in horizontal gene transfer and specifically in the acquisition and distribution of sequences that enable rapid evolution. Plasmids are components of the horizontal gene pool and, as such, their genetic content is potentially accessible by a wide range of organisms. Most plasmids appear to ameliorate any potential negative effect on host fitness by encoding determinants of virulence and ecological fitness that can enhance adaptation to a specific niche or can influence niche expansion. The availability of multiple complete genome sequences of bacterial phytopathogens has shown the importance of horizontally-acquired gene sequences in pathogen evolution. We suspect that plasmids have played a significant role in this gene mobility and also in the delivery of acquired genes to bacterial chromosomes through plasmid integration events. The versatility of plasmids plays a critical role in the evolutionary arms race of bacterial pathogens and plants.

Further reading:

Chapter 14 in Plant Pathogenic Bacteria: Genomics and Molecular Biology

Plasmids: Current Research and Future Trends

Labels: bacteriology, bacterium, plasmids

Whatever the route used, horizontal transfer of DNA requires elaborated multi-protein machinery to enable the long and charged nucleic acid polymer to cross the cell envelope barriers. The best-studied system for cell-to-cell DNA translocation is bacterial conjugation. This system can be divided in two discrete specialized modules: the relaxosome, which triggers and takes part in plasmid DNA processing and replication, and a type IV secretion system (T4SS), which impels protein and single-stranded DNA through the membranes. In addition, a coupling protein (CP), linking both modules, and a number of ancillary proteins are needed. Over the last decades research efforts in the field have resulted in the clarification of many aspects of this system and its machinery assembly. In particular, structural biology has provided details of the molecular architecture of several of the pieces involved in this intricate scenario.

Further reading: Plasmids: Current Research and Future Trends

Labels: conjugation, DNA, plasmids