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Uptake of plasmid deoxyribonucleic acid by Haemophilus
Abstract:
The uptake of circular and linear plasmid RSF0885 deoxyribonucleic acids, (DNAs) obtained from Haemophilus parainfluenzae 14, in both homologous and heterologous recipients was studied and compared with that of chromosomal DNA. High concentrations of divalent cations stimulated the uptake of either circular or linear plasmid DNA in H. parainfluenzae 14 competent cells but did not affect the uptake of chromosomal DNA. The biological activity of linear plasmid DNA was similar to that of circular DNA, and the transforming efficiencies for ampicillin resistance of both molecular forms were stimulated by divalent ions. Plasmid DNA was taken up efficiently either with or without the addition of divalent ions but was not biologically active in the heterologous Haemophilus influenzae Rd recipient. Our results suggest that in H. parainfluenzae 14 some of the steps for chromosomal and plasmid DNA uptake are different.
Insights
This study shows that divalent cations enhance plasmid deoxyribonucleic acid (DNA) uptake in Haemophilus parainfluenzae 14. However, chromosomal DNA uptake was unaffected, suggesting distinct uptake mechanisms for plasmid and chromosomal DNA.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Plasmid deoxyribonucleic acids (DNAs) are crucial for bacterial adaptation and evolution.
- Understanding DNA uptake mechanisms is vital for genetic manipulation and understanding bacterial interactions.
Purpose of the Study:
- To investigate and compare the uptake of circular and linear plasmid RSF0885 DNA with chromosomal DNA in Haemophilus parainfluenzae 14.
- To determine the effect of divalent cations on DNA uptake in homologous and heterologous recipients.
Main Methods:
- Studied the uptake of circular and linear plasmid RSF0885 DNA and chromosomal DNA in Haemophilus parainfluenzae 14.
- Compared DNA uptake in homologous (H. parainfluenzae 14) and heterologous (Haemophilus influenzae Rd) recipients.
- Assessed the impact of high concentrations of divalent cations on DNA uptake and biological activity.
Main Results:
- High concentrations of divalent cations significantly stimulated the uptake of both circular and linear plasmid DNA in H. parainfluenzae 14 competent cells.
- Divalent cations did not affect the uptake of chromosomal DNA.
- Linear plasmid DNA exhibited similar biological activity to circular DNA, with both forms showing stimulated transforming efficiencies for ampicillin resistance by divalent ions.
- Plasmid DNA uptake was efficient with or without divalent ions but lacked biological activity in the heterologous H. influenzae Rd recipient.
Conclusions:
- The findings suggest that distinct mechanisms govern the uptake of chromosomal and plasmid DNA in H. parainfluenzae 14.
- Divalent cations play a role in facilitating plasmid DNA uptake, but not chromosomal DNA uptake, in this species.