title: Genetic recombination by spheroplast fusion in Escherichia coli K12.
abstract: Genetic transfer mediated by spheroplast formation and fusion in Escherichia coli was studied. Recombination did not occur from spheroplasts prepared by the combined glycine and lysozyme-EDTA treatment described by Coetzee et al. (1979). In contrast, when bacteria were exposed to a sub-inhibitory concentration of polymyxin B (0.5 microgram/ml) during the spheroplast generation phase, recombinants arose at frequencies of 1 x 10(-8) to 2.6 x 10(-8). The incidence of genetic transfer was further increased by adding 0.01 M CaCl2 to the polyethylene glycol fusion mixture (from 9 x 10(-7) to 9 x 10(-8). Finally, when the effects of both polymyxin B and calcium chloride were combined recombinants arose at frequencies of 3.4 x 10(-6) to 7.3 x 10(-7). These findings suggest that the detergent-like action of polymyxin B in removing a large part of the outer membrane enhances plasma membrane availability where fusion can take place.
authors.affiliation: Institute of Microbiology, University of Genoa, Italy.
authors.forename: S
authors.initials: S
authors.lastname: Reina
authors.forename: E A
authors.initials: EA
authors.lastname: Debbia
authors.forename: G C
authors.initials: GC
authors.lastname: Schito
mesh_terms: D002122:Calcium Chloride / Q000494:pharmacology; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics*; D017353:Gene Deletion; D018014:Gene Transfer Techniques; D008561:Membrane Fusion; D011112:Polymyxin B / Q000494:pharmacology; D011995:Recombination, Genetic / Q000502:physiology*; D013104:Spheroplasts / Q000187:drug effects / Q000378:metabolism*
chemical_list: D011112:Polymyxin B; D002122:Calcium Chloride