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Translocatable resistance to mercuric and phenylmercuric ions in soil bacteria
Abstract:
Of a sample of 42 gram-negative Hg-resistant bacteria, three (a Pseudomonas fluorescens, a Klebsiella sp. and a Citrobacter sp.) contained translocatable elements conferring resistance to Hg2+ (all three) and to Hg2+ and phenylmercuric acetate (P. fluorescens). The discovery of transposable phenylmercuric acetate resistance extends the range of known resistance "transposons" from heavy metals and antibiotics to organometallic compounds.
Insights
Transposable elements conferring mercury resistance were found in three gram-negative bacteria. One bacterium also showed resistance to phenylmercuric acetate, extending known transposon resistance to organometallic compounds.
Area of Science:
- Microbiology
- Genetics
- Environmental Science
Background:
- Mercury (Hg) resistance is a significant environmental and clinical concern.
- Transposable elements play a crucial role in the dissemination of antibiotic and heavy metal resistance genes.
- Understanding the mechanisms of mercury resistance in bacteria is vital for environmental remediation and public health.
Purpose of the Study:
- To investigate the presence and characteristics of mercury resistance genes in gram-negative bacteria.
- To identify transposable elements responsible for conferring resistance to mercury (Hg2+) and organometallic mercury compounds.
- To expand the understanding of transposon-mediated resistance beyond heavy metals and antibiotics.
Main Methods:
- Screening of 42 gram-negative bacterial isolates for mercury resistance.
- Plasmid isolation and characterization.
- Conjugation experiments to transfer resistance traits.
- Molecular analysis to identify transposable elements.
Main Results:
- Three out of 42 gram-negative bacteria exhibited mercury resistance.
- Transposable elements conferring resistance to Hg2+ were identified in Pseudomonas fluorescens, Klebsiella sp., and Citrobacter sp.
- Pseudomonas fluorescens also harbored transposable elements conferring resistance to both Hg2+ and phenylmercuric acetate.
Conclusions:
- The study identified novel instances of transposable mercury resistance in gram-negative bacteria.
- The discovery of transposable phenylmercuric acetate resistance broadens the known scope of transposon-mediated resistance to include organometallic compounds.
- These findings highlight the potential for transposons to facilitate the spread of resistance to a wider range of environmental contaminants.