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Transformation reactions between Pneumococcus and three strains of Streptococci

R M BRACCO, M R KRAUSS, A S ROE

    The Journal of Experimental Medicine
    |August 1, 1957
    PubMed

    Insights

    Bacterial transformation allows streptomycin resistance transfer between distantly related streptococci. Transformation efficiency does not necessarily reflect bacterial relatedness, challenging traditional classification.

    Area of Science:

    • Microbiology
    • Genetics
    • Molecular Biology

    Background:

    • Bacterial transformation is a key mechanism for genetic exchange.
    • Streptococci exhibit diverse relationships and genetic capabilities.
    • Streptomycin resistance and optochin resistance are important bacterial traits.

    Purpose of the Study:

    • To investigate reciprocal transformation reactions between pneumococcus and viridans streptococci.
    • To determine the role of desoxyribonucleic acid (DNA) in mediating these transformations.
    • To assess the relationship between transformation efficiency and bacterial relatedness.

    Main Methods:

    • Extraction of desoxyribonucleic acid (DNA) from streptomycin-resistant Streptococcus salivarius.
    • Transformation assays using DNA extracts on pneumococcus and viridans streptococci strains.
    • Evaluation of reciprocal transformation efficiencies.
    • Testing the transferability of optochin resistance.

    Main Results:

    • Reciprocal transformation to streptomycin resistance occurred between pneumococcus and two viridans streptococci strains.
    • DNA extracts from resistant Streptococcus salivarius transformed other strains, but not itself.
    • Viridans streptococci strains were more efficient receptors than pneumococcus.
    • Transforming principle efficiency increased in pneumococcus after reduplication, while streptococcal transformation efficiency decreased.
    • Optochin resistance was transferable to pneumococcus.

    Conclusions:

    • Bacterial relatedness does not solely determine transformation efficiency.
    • Transformation can occur between distantly related bacterial species.
    • Genetic exchange mechanisms like transformation challenge traditional bacteriological classification.
    • Transformation provides a pathway for acquiring antibiotic resistance traits.
    Keywords:
    DESOXYRIBONUCLEIC ACID/effectsDIPLOCOCCUS PNEUMONIAESTREPTOCOCCUS

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