Factors affecting transfer frequency of pAM beta 1 from Streptococcus faecalis to Lactobacillus plantarum

Area of Science:

• Microbiology
• Molecular Biology
• Bacteriology

Background:

• Conjugal plasmid transfer is a key mechanism for bacterial genetic exchange.
• Streptococcal plasmids, like pAM beta 1, are important in microbial genetics and biotechnology.
• Lactobacillus plantarum is a significant probiotic and industrial microorganism.

Purpose of the Study:

• To investigate the optimal conditions for the filter mating method of conjugal plasmid transfer.
• To determine the influence of membrane filter characteristics on the transfer frequency of plasmid pAM beta 1.
• To evaluate the effect of post-trapping sterile water passage on conjugation efficiency.

Main Methods:

• Filter mating technique was employed to transfer streptococcal plasmid pAM beta 1.
• Donor (Streptococcus) and recipient (Lactobacillus plantarum) cells were co-cultured on membrane filters.
• Various membrane filter types, pore sizes, and orientations were tested.
• The effect of passing sterilized water through the filter post-incubation was assessed.

Main Results:

• Plasmid transfer frequency was highly sensitive to membrane filter type, pore size, and filter side.
• Sterilized water passage through the membrane after cell trapping increased transfer frequency approximately 10-fold.
• Specific filter parameters significantly influenced the efficiency of intergeneric plasmid transfer.

Conclusions:

• The filter mating method can be optimized for efficient conjugal transfer of pAM beta 1 to Lactobacillus plantarum.
• Membrane filter selection and a sterile water washing step are critical for maximizing transfer efficiency.
• This optimized method facilitates genetic manipulation of Lactobacillus plantarum using streptococcal plasmids.