title: Transduction of R factors by a Proteus mirabilis bacteriophage.
abstract: A transducing phage, designated phim, was isolated from a lysogenic strain of Proteus mirabilis and was characterized with respect to its physical and genetic properties. The phage contains double-stranded deoxyribonucleic acid (DNA) with an S(20,w) degrees of 29 which corresponds to a molecular weight of 24 x 10(6) daltons. The base composition of phim DNA was estimated to be 40% guanine plus cytosine on the basis of the buoyant density of the DNA. phim carries out generalized transduction of chromosomal genes in P. mirabilis at a frequency of 5 x 10(-8) to 2 x 10(-6) per adsorbed phage. To obtain R-factor transduction, it was necessary to have a resident R factor in the recipient cells. In these experiments, different combinations of genetically distinguishable R factors were used in the donor and recipient cells. The frequencies of R-factor transduction were 10(-9) to 2 x 10(-8). The transduction of R factors using an R(-) recipient could not be detected. Transductant R factors were usually recombinant between donor and resident R factors. All of the transduced R factors were transferable by conjugation. A plausible explanation for the requirement for a resident R factor in the recipient cells is that phim transduces only a portion of the R-factor genome and therefore requires a resident R factor for genetic recombination. The reason for the low frequencies of R-factor transduction is not known, but some possible interpretations have been discussed.
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001435:Bacteriophages / Q000032:analysis / Q000302:isolation & purification; D002499:Centrifugation, Density Gradient; D002586:Cesium; D002712:Chlorides; D002725:Chloroform; D002876:Chromosomes, Bacterial; D003227:Conjugation, Genetic; D003596:Cytosine / Q000032:analysis; D004279:DNA, Viral / Q000032:analysis / Q000302:isolation & purification; D004352:Drug Resistance, Microbial; D004926:Escherichia coli / Q000187:drug effects; D005374:Filtration; D005827:Genetics, Microbial; D006147:Guanine / Q000032:analysis; D008242:Lysogeny; D008854:Microscopy, Electron; D008970:Molecular Weight; D010636:Phenols; D010772:Phosphotungstic Acid; D011511:Proteus / Q000187:drug effects*; D011995:Recombination, Genetic; D013053:Spectrophotometry; D013194:Staining and Labeling; D013449:Sulfonamides / Q000494:pharmacology; D014161:Transduction, Genetic; D014461:Ultracentrifugation
chemical_list: D000900:Anti-Bacterial Agents; D002712:Chlorides; D004279:DNA, Viral; D010636:Phenols; D013449:Sulfonamides; D010772:Phosphotungstic Acid; D002586:Cesium; D006147:Guanine; D002725:Chloroform; D003596:Cytosine