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Transformation and expression of a staphylococcal plasmid in Escherichia coli
1Department of Physiology, University College of Science and Technology, Calcutta, India.
Abstract:
A multiple antibiotic-resistant Staphylococcus aureus, was found to possess three plasmid bands in agarose gel electrophoresis. A plasmid of approximately 4.3 kb (pMC790/2) was found to code for ampicillin and tetracycline resistance and to have one EcoRI site when transformed into S. aureus RN 4220. pMC790/2 in unmodified form was transformed into a recA- E. coli at a frequency of 1.2 x 10(4) transformants/micrograms of plasmid DNA. Plasmid (pMC790/2) replicated, maintained itself stably and expressed far better in the E. coli host than in S. aureus.
Insights
A novel plasmid, pMC790/2, from antibiotic-resistant Staphylococcus aureus confers ampicillin and tetracycline resistance. This plasmid functions more effectively in Escherichia coli than in its native S. aureus host.
Area of Science:
- Molecular Biology
- Microbiology
- Genetics
Background:
- Multiple antibiotic-resistant Staphylococcus aureus poses a significant public health threat.
- Understanding the genetic elements, such as plasmids, responsible for antibiotic resistance is crucial for developing effective treatments.
Purpose of the Study:
- To characterize a specific plasmid (pMC790/2) identified in a multi-drug resistant Staphylococcus aureus strain.
- To investigate the functional expression and stability of this plasmid in different bacterial hosts.
Main Methods:
- Agarose gel electrophoresis was used to identify plasmid bands.
- Transformation experiments were conducted to introduce the plasmid into Staphylococcus aureus RN 4220 and a recA- Escherichia coli strain.
- Antibiotic resistance gene expression and plasmid stability were assessed in both hosts.
Main Results:
- A 4.3 kb plasmid, designated pMC790/2, was isolated and found to confer resistance to ampicillin and tetracycline.
- The plasmid exhibited a single EcoRI restriction site.
- pMC790/2 demonstrated significantly enhanced replication, stable maintenance, and gene expression in the Escherichia coli host compared to Staphylococcus aureus.
Conclusions:
- The pMC790/2 plasmid carries genes conferring resistance to ampicillin and tetracycline.
- Escherichia coli serves as a more efficient host for the stable maintenance and functional expression of this Staphylococcus aureus plasmid.