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Chromate resistance plasmid in Pseudomonas fluorescens
Journal of Bacteriology
|September 1, 1983
Summary
Chromate resistance in Pseudomonas fluorescens LB300 is determined by a specific plasmid (pLHB1). This plasmid, when transferred to other bacteria like Escherichia coli, also confers resistance to chromate, highlighting its role in heavy metal tolerance.
Area of Science:
- Environmental Microbiology
- Bacterial Genetics
- Bioremediation
Background:
- Pseudomonas fluorescens LB300 was isolated from chromium-contaminated sediment.
- Chromate contamination poses environmental and health risks.
- Understanding microbial resistance mechanisms is crucial for bioremediation strategies.
Purpose of the Study:
- To investigate the genetic basis of chromate resistance in Pseudomonas fluorescens LB300.
- To determine if the resistance phenotype is transferable via plasmids.
Main Methods:
- Isolation of Pseudomonas fluorescens LB300 from contaminated environmental samples.
- Plasmid curing using mitomycin C and spontaneous segregation to eliminate pLHB1.
- Transformation experiments using purified pLHB1 plasmid DNA.
- Conjugation experiments to transfer pLHB1 to Escherichia coli.
Main Results:
- Loss of the plasmid pLHB1 resulted in a simultaneous loss of chromate resistance.
- Re-introduction of pLHB1 restored the chromate resistance phenotype.
- Transfer of pLHB1 to Escherichia coli conferred chromate resistance in the recipient strain.
Conclusions:
- Chromate resistance in Pseudomonas fluorescens LB300 is plasmid-specified by pLHB1.
- The pLHB1 plasmid carries the genetic determinants for chromate resistance.
- This plasmid-mediated resistance can be transferred between bacterial species, with implications for heavy metal adaptation in microbial communities.