Pathway of plasmid transformation in Pneumococcus: open circular and linear molecules are active

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Genomic Transformation of the Picoeukaryote Ostreococcus tauri
10:45

Genomic Transformation of the Picoeukaryote Ostreococcus tauri

Published on: July 13, 2012

C W Saunders, W R Guild

    Journal of Bacteriology
    |May 1, 1981
    PubMed

    Insights

    Different forms of plasmid pMV158, including open circular and linear, can transform Streptococcus pneumoniae, though less efficiently than closed circular forms. This suggests a novel mechanism of plasmid assembly within recipient cells.

    Area of Science:

    • Molecular Biology
    • Microbiology
    • Genetics

    Background:

    • Plasmid transformation is crucial for genetic exchange in bacteria.
    • Streptococcus pneumoniae is a key model organism for studying bacterial genetics.
    • The role of different plasmid forms in transformation efficiency requires further elucidation.

    Purpose of the Study:

    • To investigate the transformation activity of various forms of plasmid pMV158 in Streptococcus pneumoniae.
    • To compare the transformation efficiencies of open circular and linear plasmid forms with closed circular forms.
    • To understand the mechanism underlying plasmid transformation in this bacterium.

    Main Methods:

    • Analysis of S1 nuclease-digested plasmid deoxyribonucleic acid (DNA).
    • Utilized dye-buoyancy, gel electrophoresis, and sedimentation velocity methods.
    • Studied transformation kinetics using monomeric and dimeric plasmid forms.

    Main Results:

    • Monomeric and dimeric open circular and linear forms of pMV158 demonstrated transformation activity.
    • These forms were at least 35-fold less efficient than closed circular forms.
    • Transformation efficiencies were low even for closed circular donors.
    • Results support a model of replicon assembly via single-strand fragment pairing.

    Conclusions:

    • Various plasmid forms contribute to transformation in Streptococcus pneumoniae.
    • Transformation efficiency is significantly influenced by plasmid topology.
    • A novel mechanism involving single-strand fragment recombination may underlie plasmid transformation.

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