Natural transformation in Campylobacter species

Area of Science:

• Microbiology
• Molecular Biology
• Bacterial Genetics

Background:

• Campylobacter species are significant human pathogens.
• Efficient genetic manipulation tools are crucial for studying Campylobacter pathogenesis and developing interventions.
• Natural transformation, a mechanism for genetic exchange, has not been extensively characterized in Campylobacter.

Purpose of the Study:

• To investigate the feasibility of natural transformation in Campylobacter coli and Campylobacter jejuni using naked DNA.
• To characterize the efficiency and specificity of DNA uptake in these bacteria.
• To demonstrate the introduction of a novel antibiotic resistance gene into Campylobacter.

Main Methods:

• Culturing of Campylobacter coli and C. jejuni.
• Exposure of bacterial cells to homologous and heterologous chromosomal DNA and plasmid DNA.
• Construction and transformation with novel Campylobacter-E. coli shuttle plasmids.
• Introduction of the tetM determinant via natural transformation.

Main Results:

• Campylobacter cells exhibited natural transformation with naked DNA without special treatment.
• Transformation frequencies for homologous chromosomal DNA were approximately 10(-3) in C. coli and 10(-4) in C. jejuni.
• Campylobacters showed preferential uptake of homologous DNA over E. coli DNA.
• Plasmid DNA transformation was less efficient, especially into plasmid-free cells, but successful with homologous plasmid recipients.
• The tetM determinant was successfully introduced into C. coli, conferring tetracycline resistance.

Conclusions:

• Natural transformation is a viable mechanism for genetic modification in Campylobacter coli and C. jejuni.
• The study establishes conditions for efficient homologous DNA uptake and demonstrates the utility of shuttle plasmids.
• Successful introduction of the tetM determinant expands the genetic toolbox for Campylobacter research.