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Influence of transformability on the formation of superinfection double lysogens in Haemophilus influenzae
Abstract:
Superinfection of growing (nontransformable) cells of defectively lysogenic strains of Haemophilus influenzae with wild-type or with mutant phage HP1 resulted in a number of double lysogens and a small number of monolysogens with altered prophage. The double lysogens were identified by analysis of their monolysogenic segregants and by examining their deoxyribonucleic acid in certain test crosses. The results indicate that the majority had been formed by insertion of the infecting phage genome within the resident prophage. Superinfection of transformable bacteria gave rise to cells with altered prophages (presumably transformants) and to double lysogens which had gained or lost wild-type prophage loci.
Insights
Superinfection of Haemophilus influenzae with phage HP1 created double lysogens by inserting new phage DNA into existing prophage. This process altered bacterial prophages and affected genetic loci in transformable strains.
Area of Science:
- Microbiology
- Molecular Biology
- Bacteriology
Background:
- Lysogenic bacteria harbor prophage DNA integrated into their genome.
- Superinfection involves introducing a new phage to a lysogenic host.
- Haemophilus influenzae is a significant human pathogen.
Purpose of the Study:
- To investigate the mechanisms of prophage integration during superinfection in Haemophilus influenzae.
- To characterize the genetic alterations in prophages and hosts following superinfection with phage HP1.
Main Methods:
- Superinfection of growing nontransformable and transformable Haemophilus influenzae strains with wild-type and mutant phage HP1.
- Identification of double lysogens through analysis of monolysogenic segregants.
- Deoxyribonucleic acid analysis and test crosses to examine prophage integration and alterations.
Main Results:
- Superinfection predominantly resulted in the insertion of the infecting phage genome within the resident prophage, forming double lysogens.
- A small number of monolysogens with altered prophages were observed.
- In transformable bacteria, superinfection led to altered prophages and double lysogens with gained or lost wild-type prophage loci.
Conclusions:
- The primary outcome of phage HP1 superinfection in Haemophilus influenzae is the integration of the new phage genome into the existing prophage.
- Superinfection can lead to significant genetic modifications of both the prophage and the bacterial host, impacting genetic loci.