Resistance plasmids in Pseudomonas cepacia 4G9.

Area of Science:

• Microbiology
• Molecular Biology
• Genetics

Background:

• Pseudomonas cepacia 4G9 exhibits 2-tridecanone utilization and antibiotic resistance.
• The genetic basis for these traits, specifically plasmid mediation, was investigated.

Purpose of the Study:

• To determine if 2-tridecanone utilization and antibiotic resistance in Pseudomonas cepacia 4G9 are plasmid-mediated.
• To characterize the plasmids involved in conferring these traits.

Main Methods:

• Transformation of Escherichia coli HB101 with plasmid DNA from Pseudomonas cepacia 4G9.
• Selection for transformants exhibiting antibiotic resistance.
• Plasmid DNA isolation and molecular weight determination via electron microscopy.

Main Results:

• No transformants utilizing 2-tridecanone were obtained.
• Tetracycline and ampicillin resistance were transferred at low frequencies.
• Plasmids pJW2 (2.9 x 10^6 Da) and pJW3 (5.4 x 10^6 Da) conferred tetracycline and ampicillin resistance, respectively.
• Pseudomonas cepacia 4G9 contains plasmid pJW1 (1.78 x 10^6 Da).
• Tetracycline resistance was inducible, while ampicillin resistance was constitutive in P. cepacia 4G9.

Conclusions:

• Antibiotic resistance, but not 2-tridecanone utilization, in Pseudomonas cepacia 4G9 is plasmid-mediated.
• Distinct plasmids confer tetracycline and ampicillin resistance.
• Differences in resistance expression were observed between the native host and transformants.