A new simple method of curing plasmids in lactic streptococci (Streptococcus cremoris; Streptococcus lactis,...

Area of Science:

• Microbiology
• Molecular Biology
• Genetics

Background:

• Plasmid DNA is crucial for genetic traits in many bacteria, including lactic streptococci.
• Efficient plasmid removal is essential for genetic manipulation and studying bacterial functions.
• Existing plasmid curing methods often involve harsh chemicals, posing safety and environmental concerns.

Purpose of the Study:

• To develop a simple, non-chemical method for plasmid DNA curing in lactic streptococci.
• To evaluate the efficacy of extended incubation in an unbuffered medium for plasmid loss.

Main Methods:

• Lactic streptococci strains were cultured overnight in unbuffered M17- medium at 32°C.
• Cultures were then incubated at 32°C for an extended period (96 hours).
• Plasmid DNA loss was assessed using gel electrophoresis after one or two cycles of this process.

Main Results:

• Extended incubation in M17- medium at 32°C induced the loss of plasmid DNA of various sizes.
• Repeating the growth and extended incubation process resulted in the loss of most plasmids.
• The method proved effective without the use of mutagenic chemicals.

Conclusions:

• A straightforward and efficient method for curing plasmid DNA from lactic streptococci has been established.
• This technique utilizes controlled environmental conditions (temperature and pH) to induce plasmid loss.
• The developed method offers a safe and effective alternative to chemical-based plasmid curing strategies.