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Detection and quantitation of Staphylococcus aureus penicillinase plasmid deoxyribonucleic acid by reassociation
Abstract:
The quantity of penicillinase plasmid deoxyribonucleic acid (DNA) in various strains of Staphylococcus aureus has been determined by DNA-DNA reassociation kinetics. Specifically, 32P- or 125I-labeled denatured probes of purified plasmid DNA were reassociated in the presence of denatured DNAs isolated from the bacterial strains in question. The number of plasmid copies per cell was calculated from the effect of the latter nucleic acid samples on the reassociation rate of the radiolabeled probe. Among the S. aureus strains examined were monoplasmid, diplasmid and replication-defective representatives, and the effect of temperature on wild-type plasmid content was also investigated.
Insights
Researchers quantified penicillinase plasmid deoxyribonucleic acid (DNA) in Staphylococcus aureus strains using DNA-DNA reassociation kinetics. This method determined plasmid copy numbers per cell across various strains and conditions.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- Penicillinase plasmids are crucial genetic elements in Staphylococcus aureus.
- Understanding plasmid quantity is essential for studying bacterial genetics and antibiotic resistance.
Purpose of the Study:
- To quantify penicillinase plasmid deoxyribonucleic acid (DNA) in diverse Staphylococcus aureus strains.
- To investigate the impact of different plasmid configurations and temperature on plasmid copy number.
Main Methods:
- Utilized DNA-DNA reassociation kinetics for precise plasmid quantification.
- Employed radiolabeled plasmid DNA probes (32P or 125I) for reassociation assays.
- Calculated plasmid copy number per cell based on reassociation rate changes.
Main Results:
- Successfully quantified plasmid DNA in monoplasmid, diplasmid, and replication-defective S. aureus strains.
- Determined the effect of temperature variations on wild-type plasmid content.
- Established a reliable method for assessing plasmid copy numbers in bacterial populations.
Conclusions:
- DNA-DNA reassociation kinetics provides an accurate method for determining plasmid DNA quantity in S. aureus.
- Plasmid copy number varies among different S. aureus strains and is influenced by environmental factors like temperature.