• Genetic and molecular events in transformation ofHaemophilus influenzae with plasmid RSF 0885 carrying cloned segments of chromosomal DNA

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    • Keywords


      Haemophilus influenzae ; Plasmid transformation; recombinant DNA; uptake sequences; rec gene requirement

    • Abstract


      InHaemophilus influenzae genetic transformation for a plasmid marker is significantly increased when recombinant plasmid RSF 0885 DNA carrying chromosomal DNA segments is used instead of the plasmid DNA alone. Chromosomal DNA by itself, added even a few minutes after the addition of plasmid DNA to competent cells, stopped further uptake of the plasmid DNA. These observations are consistent with the idea that plasmid RSF 0885 contains a ‘degenerate’ version of the required eleven base-pair ‘uptake sequence’ inHaemophilus. The transformation activity of the recombinant plasmid DNA is recoverable after its entry into cells, although the specific biological activity of the re-isolated plasmid DNA is less than that of the parental recombinant plasmid DNA. Therec 1 gene function of the host is necessary for obtaining higher transformation frequencies with recombinant DNA from five different clones. The reduced transformation frequencies seen inrec 1- strain is not all due to a permanent damage to the donor DNA since the recovered recombinant plasmid DNA from such cells can increase the transformation efficiency onrec 1+ strain.

    • Author Affiliations


      N K Notani1

      1. Biology and Agriculture Division, Bhabha Atomic Research Centre, Bombay - 400 085
    • Dates

  • Journal of Biosciences | News

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      Posted on July 25, 2019

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