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Functional analysis of pVT745, a plasmid from Actinobacillus actinomycetemcomitans
K F Novak1, L N Lee, D J LeBlanc
1Division of Oral Biology, University of Pittsburgh, Pennsylvania 15261, USA.
Oral Microbiology and Immunology
|May 9, 1998
Summary
Plasmid pVT745 from Actinobacillus actinomycetemcomitans shows stable genetic elements. Further research is needed to understand its role and potential for antibiotic resistance gene transfer.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Plasmid pVT745, a 25.1-kb replicon from Actinobacillus actinomycetemcomitans strain VT745, exhibits homology with chromosomal DNA in other strains.
- This homology suggests the presence of mobile genetic elements like insertion sequences or transposons, potentially conferring antibiotic resistance.
Purpose of the Study:
- To investigate the nature and mobility of plasmid pVT745 and its homologous DNA sequences within Actinobacillus actinomycetemcomitans.
- To determine if pVT745 represents a lysogenic bacteriophage or contains mobile elements responsible for antibiotic resistance.
Main Methods:
- Southern hybridization was used to analyze the chromosomal DNA of A. actinomycetemcomitans strains after cell passaging experiments.
- Phage induction experiments were performed to test for lysogenic bacteriophage activity.
- Attempts were made to cure strain VT745 of the plasmid pVT745.
Main Results:
- The homologous DNA sequences of pVT745 appeared stable within the chromosome and on the plasmid, showing no evidence of transposition.
- Phage induction experiments failed to release any phage from strain VT745.
- Successful curing of strain VT745 from pVT745 was not achieved.
Conclusions:
- Plasmid pVT745 and its homologous DNA elements exhibit genetic stability within Actinobacillus actinomycetemcomitans.
- The results do not support the hypothesis that pVT745 contains mobile genetic elements responsible for widespread antibiotic resistance or that it is a lysogenic bacteriophage.