Similarities between plasmids of the P-incompatibility group derived from different bacterial genera

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High-Resolution Comparison of Bacterial Conjugation Frequencies
05:18

High-Resolution Comparison of Bacterial Conjugation Frequencies

Published on: January 10, 2019

V A Stanisich, J M Ortiz

    Journal of General Microbiology
    |June 1, 1976
    PubMed

    Insights

    This study compared P-group plasmids, finding that most genes controlling plasmid characteristics are linked to the transfer factor, except for aeruginocin-insensitivity. This suggests a common ancestor for these plasmids, with variations arising from recombination events.

    Area of Science:

    • Microbiology
    • Molecular Biology
    • Genetics

    Background:

    • P-group plasmids are a significant class of bacterial genetic elements.
    • Understanding plasmid properties is crucial for tracking antibiotic resistance and bacterial evolution.
    • Comparative analysis of related plasmids reveals insights into their genetic structure and evolutionary history.

    Purpose of the Study:

    • To compare the properties of four P-group plasmids (R26, R527, R751, R906) with the prototype RPI.
    • To investigate the genetic basis for differences in resistance phenotypes and other characteristics among these plasmids.
    • To determine the evolutionary relationships and potential common ancestry of these P-group plasmids.

    Main Methods:

    • Comparative analysis of plasmid properties including incompatibility, response to specific phages (aeruginocin, male, female sex-specific), interaction with prophage B3, and fertility inhibition by plasmid R38.
    • Characterization of new plasmid isolates (R26, R527) based on incompatibility with known P-group plasmids.
    • Transduction experiments to assess the 'rescue' of plasmid determinants by other P-group plasmids.

    Main Results:

    • Four P-group plasmids (R26, R527, R751, R906) showed similar behavior across most tested properties, except for aeruginocin response.
    • The locus for aeruginocin-insensitivity was identified as an R-determinant, while other genes were closely linked to the transfer factor.
    • Transduction experiments demonstrated that plasmid determinants could be rescued by the P-group plasmid R18 in a functional host recombination system.

    Conclusions:

    • The observed similarities suggest a common ancestor for these P-group plasmids.
    • Differences in resistance phenotypes likely result from subsequent recombination events.
    • The findings support a model where core plasmid functions are conserved, with accessory genes undergoing variation.

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