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A transferable plasmid associated with AS-48 production in Enterococcus faecalis
M Martínez-Bueno1, A Gálvez, E Valdivia
1Departamento de Microbiología, Facultad de Ciencias, Universidad de Granada, Spain.
Abstract:
Enterococcus faecalis S-48 produces a peptide antibiotic, AS-48, and a bacteriocin, Bc-48. We have isolated mutants that lack these inhibitory characteristics. Further analysis of the mutants indicates that a plasmid of 56 kilobases (pMB2) may harbor the genes for AS-48. In conjugation experiments, pMB2 has been transferred into a plasmid-free OG1X strain of E. faecalis. The OG1X(pMB2) transconjugant produces the antibiotic AS-48 in solid medium, and the MIC of AS-48 for this strain is the same as that of the donor strain.
Insights
Enterococcus faecalis S-48 produces the antibiotic AS-48. A 56-kilobase plasmid (pMB2) was identified as potentially carrying the AS-48 genes, confirmed by successful transfer and production in a new strain.
Area of Science:
- Microbiology
- Bacteriology
- Molecular Biology
Background:
- Enterococcus faecalis S-48 is known to produce the peptide antibiotic AS-48 and a bacteriocin, Bc-48.
- Investigating the genetic basis of AS-48 production is crucial for understanding its biosynthesis and potential applications.
Purpose of the Study:
- To identify the genetic elements responsible for AS-48 production in Enterococcus faecalis S-48.
- To confirm the role of a specific plasmid in AS-48 biosynthesis and activity.
Main Methods:
- Isolation and characterization of Enterococcus faecalis S-48 mutants lacking inhibitory properties.
- Plasmid DNA analysis to identify potential gene-carrying plasmids.
- Conjugation experiments to transfer plasmids between E. faecalis strains.
- Determination of Minimum Inhibitory Concentration (MIC) of AS-48.
Main Results:
- Mutants lacking AS-48 and Bc-48 production were successfully isolated.
- A 56-kilobase plasmid, designated pMB2, was identified as potentially harboring the AS-48 genes.
- Transfer of pMB2 into a plasmid-free E. faecalis strain (OG1X) resulted in AS-48 production.
- The transconjugant strain OG1X(pMB2) exhibited AS-48 production with an MIC comparable to the donor strain.
Conclusions:
- The 56-kilobase plasmid pMB2 contains the genetic determinants for AS-48 production in Enterococcus faecalis S-48.
- Successful transfer of pMB2 confers AS-48 antibiotic activity to a recipient strain, validating its role in biosynthesis.