Methods for detection of conjugative plasmid transfer in aquatic environments.
Donor and recipient counter selection was evaluated by selecting bacteria that received plasmid RP4 by conjugation on filters and in lake water microcosms. Three counter selection systems were compared; (i) Use of antibiotic-resistant recipients, (ii) use of an auxotrophic donor, and (iii) use of a donor with chromosomal suicide genes. Transfer efficiencies of transconjugants per recipient obtained with the three different counter selection systems in filter-matings were not significantly different. Some nalidixic acid-resistant recipients became partly sensitive to nalidixic acid after receiving the plasmid. Use of an auxotrophic donor was a feasible and easy way to recover indigenous transconjugants. A strain with two copies of the suicide gene gef was successfully eliminated in filter-matings, but elimination of the donor in microcosms by induction of the suicide genes did not succeed. Thus, this counter selection system was not usable in microcosm experiments.
Sengeløv
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Department of General Microbiology, Institute of Molecular Biology, University of Copenhagen, Solvgade 83H, DK-1307 Copenhagen K, Denmark.
Sørensen
S J
SJ
D001419:Bacteria / Q000235:genetics*; D001426:Bacterial Proteins / Q000235:genetics; D001427:Bacterial Toxins; D003227:Conjugation, Genetic; D004352:Drug Resistance, Microbial / Q000235:genetics; D004926:Escherichia coli / Q000235:genetics; D029968:Escherichia coli Proteins; D005798:Genes, Bacterial; D005821:Genetic Techniques; D008565:Membrane Proteins; D010957:Plasmids / Q000235:genetics*; D011551:Pseudomonas fluorescens / Q000235:genetics; D016958:Pseudomonas putida / Q000235:genetics; D014871:Water Microbiology
D001426:Bacterial Proteins; D001427:Bacterial Toxins; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; C071524:HokC protein, E coli