title: Methods for detection of conjugative plasmid transfer in aquatic environments.
abstract: 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.
authors.affiliation: Department of General Microbiology, Institute of Molecular Biology, University of Copenhagen, Solvgade 83H, DK-1307 Copenhagen K, Denmark.
authors.forename: G
authors.initials: G
authors.lastname: Sengeløv
authors.forename: S J
authors.initials: SJ
authors.lastname: Sørensen
mesh_terms: 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
chemical_list: D001426:Bacterial Proteins; D001427:Bacterial Toxins; D029968:Escherichia coli Proteins; D008565:Membrane Proteins; C071524:HokC protein, E coli