Purification of sex pheromones specific for pMB1 and pMB2 plasmids of Enterococcus faecalis S-48

Area of Science:

• Microbiology
• Bacterial genetics
• Plasmid biology

Background:

• Enterococcus faecalis S-48 possesses two large conjugative plasmids, pMB1 and pMB2.
• These plasmids encode for antagonistic substances, suggesting a role in bacterial interactions.
• Understanding plasmid behavior and regulation is crucial in microbial ecology.

Purpose of the Study:

• To characterize the pheromone response of the conjugative plasmids pMB1 and pMB2 in Enterococcus faecalis S-48.
• To identify the specific sex pheromones that induce the response in each plasmid.
• To investigate the coexistence and stability of these pheromone-responding plasmids within the host strain.

Main Methods:

• Purification of sex pheromones using conventional reversed-phase chromatography.
• Determination of pheromone sequences responsible for plasmid induction.
• Coexistence studies of plasmids within the wild-type E. faecalis S-48 strain.

Main Results:

• Plasmid pMB1 was found to respond to pheromone cCF10.
• Plasmid pMB2 responds to a pheromone with the amino acid sequence Phe-Leu-Val-Met-Phe-Leu-Ser-Gly, identical to cPD1.
• Both pheromone-responsive plasmids were observed to coexist stably in the E. faecalis S-48 strain.

Conclusions:

• The study successfully identified the specific pheromones recognized by plasmids pMB1 and pMB2.
• The findings demonstrate a stable coexistence mechanism for these two distinct pheromone-responsive plasmids in E. faecalis.
• This research contributes to the understanding of plasmid conjugation and stability in Enterococcus species.