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Properties of IncP-2 plasmids of Pseudomonas spp
Abstract:
Thirty IncP-2 R plasmids from isolates of Pseudomonas spp. of diverse geographical origins were examined for the production of resistance properties. All the plasmids determined resistance to tellurite and all inhibited the propagation of certain DNA phages, although several patterns of phage inhibition were detected. Of the 30 plasmids, 29 determined resistance to streptomycin, 28 determined resistance to mercuric ion, and 24 determined resistance to sulfonamide. Resistance to other antibiotics, to compounds of arsenic, boron, or chromium, and to UV irradiation was less common. The degradative plasmid CAM also belonged to this group. When CAM was introduced into recipients carrying an IncP-2 R plasmid, recombinant plasmids were often formed in which antibiotic resistance and the ability to grow on camphor were transferred together to further recipients or were lost together in a strain in which IncP-2 plasmids were unstable. Such hybrid plasmid formation was rec dependent. CAM and other IncP-2 plasmids that determine UV light resistance demonstrated UV-enhanced, nonpolarized transfer of the Pseudomonas aeruginosa chromosome. By agarose gel electrophoresis, all IncP-2 R plasmids and CAM were ca. 300 X 10(6) in molecular weight.
Insights
IncP-2 R plasmids from Pseudomonas bacteria confer resistance to tellurite and streptomycin. These plasmids also inhibit DNA phages and can form hybrid plasmids with other genetic elements.
Area of Science:
- Microbiology
- Molecular Biology
- Genetics
Background:
- IncP-2 R plasmids are found in Pseudomonas species and carry various resistance genes.
- Understanding plasmid-mediated resistance is crucial for combating bacterial infections.
Purpose of the Study:
- To characterize the resistance properties of IncP-2 R plasmids from diverse geographical origins.
- To investigate the interactions between IncP-2 plasmids and other genetic elements, such as the CAM plasmid.
Main Methods:
- Plasmid DNA isolation and characterization using agarose gel electrophoresis.
- Testing of resistance properties including antibiotic resistance, heavy metal resistance, and phage inhibition.
- Introduction of plasmids into recipient strains to study hybrid plasmid formation and gene transfer.
Main Results:
- All 30 IncP-2 R plasmids conferred resistance to tellurite and inhibited DNA phage propagation.
- High prevalence of resistance to streptomycin (29/30), mercuric ion (28/30), and sulfonamide (24/30).
- The degradative plasmid CAM formed rec-dependent recombinant plasmids with IncP-2 R plasmids, co-transferring camphor degradation and antibiotic resistance.
Conclusions:
- IncP-2 R plasmids are significant reservoirs of multiple resistance traits in Pseudomonas.
- Plasmid interactions, like those observed with CAM, can lead to the dissemination of combined resistance genes.
- UV-enhanced chromosomal transfer mediated by certain IncP-2 plasmids highlights potential mechanisms for bacterial adaptation and evolution.